spi: fsl-dspi: Unify error messaging in dspi_request_dma()

Use dev_err_probe() for all messages in dspi_request_dma() for the sake of
making them uniform. While at it, fix indentation issue reported by Vladimir
Oltean.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20240204203127.1186621-3-andy.shevchenko@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Preserve error code returned by dmaengine_slave_config()

dmaengine_slave_config() may return different error codes based on
the circumstances. Preserve it instead of shadowing to -EINVAL.

Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20240204203127.1186621-2-andy.shevchenko@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use helper function devm_clk_get_enabled()

Since commit 7ef9651e9792 ("clk: Provide new devm_clk helpers for prepared
and enabled clocks"), devm_clk_get() and clk_prepare_enable() can now be
replaced by devm_clk_get_enabled() when driver enables (and possibly
prepares) the clocks for the whole lifetime of the device. Moreover, it is
no longer necessary to unprepare and disable the clocks explicitly.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Link: https://lore.kernel.org/r/20230823133938.1359106-14-lizetao1@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: switch to use modern name

Change legacy name master/target to modern name host/target or controller.

No functional changed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230807124105.3429709-7-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Use dev_err_probe() in dspi_request_dma()

It is possible for dma_request_chan() to return EPROBE_DEFER, which means
dev is not ready yet.
At this point dev_err() will have no output.

Signed-off-by: Minjie Du <duminjie@vivo.com>
Link: https://lore.kernel.org/r/20230725035038.1702-1-duminjie@vivo.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230714174955.4064174-1-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: avoid SCK glitches with continuous transfers

The DSPI controller has configurable timing for

(a) tCSC: the interval between the assertion of the chip select and the
first clock edge

(b) tASC: the interval between the last clock edge and the deassertion
of the chip select

What is a bit surprising, but is documented in the figure "Example of
continuous transfer (CPHA=1, CONT=1)" in the datasheet, is that when the
chip select stays asserted between multiple TX FIFO writes, the tCSC and
tASC times still apply. With CONT=1, chip select remains asserted, but
SCK takes a break and goes to the idle state for tASC + tCSC ns.

In other words, the default values (of 0 and 0 ns) result in SCK
glitches where the SCK transition to the idle state, as well as the SCK
transition from the idle state, will have no delay in between, and it
may appear that a SCK cycle has simply gone missing. The resulting
timing violation might cause data corruption in many peripherals, as
their chip select is asserted.

The driver has device tree bindings for tCSC ("fsl,spi-cs-sck-delay")
and tASC ("fsl,spi-sck-cs-delay"), but these are only specified to apply
when the chip select toggles in the first place, and this timing
characteristic depends on each peripheral. Many peripherals do not have
explicit timing requirements, so many device trees do not have these
properties present at all.

Nonetheless, the lack of SCK glitches is a common sense requirement, and
since the SCK stays in the idle state during transfers for tCSC+tASC ns,
and that in itself should look like half a cycle, then let's ensure that
tCSC and tASC are at least a quarter of a SCK period, such that their
sum is at least half of one.

Fixes: 95bf15f38641 ("spi: fsl-dspi: Add ~50ns delay between cs and sck")
Reported-by: Lisa Chen (陈敏捷) <minjie.chen@geekplus.com>
Debugged-by: Lisa Chen (陈敏捷) <minjie.chen@geekplus.com>
Tested-by: Lisa Chen (陈敏捷) <minjie.chen@geekplus.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20230529223402.1199503-1-vladimir.oltean@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Remove unneeded cast to same type

There is never a need to cast a pointer to the same pointer type.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/a417735ca3ff629ee897327b163b23414673f0a3.1678704562.git.geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Replace all spi->chip_select and spi->cs_gpiod references with function call

Supporting multi-cs in spi drivers would require the chip_select & cs_gpiod
members of struct spi_device to be an array. But changing the type of these
members to array would break the spi driver functionality. To make the
transition smoother introduced four new APIs to get/set the
spi->chip_select & spi->cs_gpiod and replaced all spi->chip_select and
spi->cs_gpiod references with get or set API calls.
While adding multi-cs support in further patches the chip_select & cs_gpiod
members of the spi_device structure would be converted to arrays & the
"idx" parameter of the APIs would be used as array index i.e.,
spi->chip_select[idx] & spi->cs_gpiod[idx] respectively.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de> # Rockchip drivers
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> # Aspeed driver
Reviewed-by: Dhruva Gole <d-gole@ti.com> # SPI Cadence QSPI
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> # spi-stm32-qspi
Acked-by: William Zhang <william.zhang@broadcom.com> # bcm63xx-hsspi driver
Reviewed-by: Serge Semin <fancer.lancer@gmail.com> # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230303172041.2103336-25-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: add cs-gpios support

Make the driver be able to bit-bang a GPIO for the Chip Select pin of
select peripherals.

The GPIO value is driven by the driver in that case, and none of the
hardware Chip Select bits will be populated in the PUSHR register for
the TX commands constructed for this peripheral.

Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20221111211356.545026-1-vladimir.oltean@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use devm_platform_get_and_ioremap_resource()

Use the devm_platform_get_and_ioremap_resource() helper instead of calling
platform_get_resource() and devm_ioremap_resource() separately.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220924131854.964923-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix issue with uninitialized dma_slave_config

Depending on the DMA driver being used, the struct dma_slave_config may
need to be initialized to zero for the unused data.

For example, we have three DMA drivers using src_port_window_size and
dst_port_window_size. If these are left uninitialized, it can cause DMA
failures.

For spi-fsl-dspi, this is probably not currently an issue but is still
good to fix though.

Fixes: 90ba37033cb9 ("spi: spi-fsl-dspi: Add DMA support for Vybrid")
Cc: Sanchayan Maity <maitysanchayan@gmail.com>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Cc: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20210810081727.19491-1-tony@atomide.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix a resource leak in an error handling path

'dspi_request_dma()' should be undone by a 'dspi_release_dma()' call in the
error handling path of the probe function, as already done in the remove
function

Fixes: 90ba37033cb9 ("spi: spi-fsl-dspi: Add DMA support for Vybrid")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/d51caaac747277a1099ba8dea07acd85435b857e.1620587472.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use max_native_cs instead of num_chipselect to set SPI_MCR

If cs-gpios property is used in devicetree then ctlr->num_chipselect value
may be changed by spi_get_gpio_descs().
So use ctlr->max_native_cs instead of ctlr->num_chipselect to set SPI_MCR

Fixes: 4fcc7c2292de (spi: spi-fsl-dspi: Don't access reserved fields in SPI_MCR)
Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>
Link: https://lore.kernel.org/r/20201201085916.63543-1-fido_max@inbox.ru
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: fix wrong pointer in suspend/resume

Since commit 530b5affc675 ("spi: fsl-dspi: fix use-after-free in
remove path"), this driver causes a "NULL pointer dereference"
in dspi_suspend/resume.
This is because since this commit, the drivers private data point to
"dspi" instead of "ctlr", the codes in suspend and resume func were
not modified correspondly.

Fixes: 530b5affc675 ("spi: fsl-dspi: fix use-after-free in remove path")
Signed-off-by: Zhao Qiang <qiang.zhao@nxp.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20201103020546.1822-1-qiang.zhao@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: fix NULL pointer dereference

Since commit 530b5affc675 ("spi: fsl-dspi: fix use-after-free in remove
path") this driver causes a kernel oops:

[ 1.891065] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000080
[..]
[ 2.056973] Call trace:
[ 2.059425] dspi_setup+0xc8/0x2e0
[ 2.062837] spi_setup+0xcc/0x248
[ 2.066160] spi_add_device+0xb4/0x198
[ 2.069918] of_register_spi_device+0x250/0x370
[ 2.074462] spi_register_controller+0x4f4/0x770
[ 2.079094] dspi_probe+0x5bc/0x7b0
[ 2.082594] platform_drv_probe+0x5c/0xb0
[ 2.086615] really_probe+0xec/0x3c0
[ 2.090200] driver_probe_device+0x60/0xc0
[ 2.094308] device_driver_attach+0x7c/0x88
[ 2.098503] __driver_attach+0x60/0xe8
[ 2.102263] bus_for_each_dev+0x7c/0xd0
[ 2.106109] driver_attach+0x2c/0x38
[ 2.109692] bus_add_driver+0x194/0x1f8
[ 2.113538] driver_register+0x6c/0x128
[ 2.117385] __platform_driver_register+0x50/0x60
[ 2.122105] fsl_dspi_driver_init+0x24/0x30
[ 2.126302] do_one_initcall+0x54/0x2d0
[ 2.130149] kernel_init_freeable+0x1ec/0x258
[ 2.134520] kernel_init+0x1c/0x120
[ 2.138018] ret_from_fork+0x10/0x34
[ 2.141606] Code: 97e0b11d aa0003f3 b4000680 f94006e0 (f9404000)
[ 2.147723] ---[ end trace 26cf63e6cbba33a8 ]---

This is because since this commit, the allocation of the drivers private
data is done explicitly and in this case spi_alloc_master() won't set the
correct pointer.

Also move the platform_set_drvdata() to have both next to each other.

Fixes: 530b5affc675 ("spi: fsl-dspi: fix use-after-free in remove path")
Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200928085500.28254-1-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: fix use-after-free in remove path

spi_unregister_controller() not only unregisters the controller, but
also frees the controller. This will free the driver data with it, so
we must not access it later dspi_remove().

Solve this by allocating the driver data separately from the SPI
controller.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20200923131026.20707-1-s.hauer@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: use XSPI mode instead of DMA for DPAA2 SoCs

The arch/arm64/boot/dts/freescale/fsl-ls208xa.dtsi device tree lacks DMA
channels for DSPI, so naturally, the driver fails to probe:

[ 2.945302] fsl-dspi 2100000.spi: rx dma channel not available
[ 2.951134] fsl-dspi 2100000.spi: can't get dma channels

In retrospect, this should have been obvious, because LS2080A, LS2085A
LS2088A and LX2160A don't appear to have an eDMA module at all. Looking
again at their datasheets, the CTARE register (which is specific to XSPI
functionality) seems to be documented, so switch them to XSPI mode
instead.

Fixes: 0feaf8f5afe0 ("spi: spi-fsl-dspi: Convert the instantiations that support it to DMA")
Reported-by: Qiang Zhao <qiang.zhao@nxp.com>
Tested-by: Qiang Zhao <qiang.zhao@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200910121532.1138596-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: use XSPI mode instead of DMA for DPAA2 SoCs

The arch/arm64/boot/dts/freescale/fsl-ls208xa.dtsi device tree lacks DMA
channels for DSPI, so naturally, the driver fails to probe:

[ 2.945302] fsl-dspi 2100000.spi: rx dma channel not available
[ 2.951134] fsl-dspi 2100000.spi: can't get dma channels

In retrospect, this should have been obvious, because LS2080A, LS2085A
LS2088A and LX2160A don't appear to have an eDMA module at all. Looking
again at their datasheets, the CTARE register (which is specific to XSPI
functionality) seems to be documented, so switch them to XSPI mode
instead.

Fixes: 0feaf8f5afe0 ("spi: spi-fsl-dspi: Convert the instantiations that support it to DMA")
Reported-by: Qiang Zhao <qiang.zhao@nxp.com>
Tested-by: Qiang Zhao <qiang.zhao@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200910121532.1138596-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: delete EOQ transfer mode

After the only user of the limited EOQ mode has now been converted to
DMA as of commit b09058bbf5f0 ("spi: spi-fsl-dspi: set ColdFire to DMA
mode"), we can finally delete this code.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20200823212657.2400075-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: set ColdFire to DMA mode

Set DMA transfer mode for ColdFire.

After recent fixes to fsl edma engine, this mode can be used
also for ColdFire, and from some raw mtd r/w tests it definitely
improves the transfer rate, so keeping it selected.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Link: https://lore.kernel.org/r/20200816094635.1830006-1-angelo.dureghello@timesys.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Initialize completion before possible interrupt

The interrupt handler calls completion and is IRQ requested before the
completion is initialized. Logically it should be the other way.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200622110543.5035-4-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix external abort on interrupt in resume or exit paths

If shared interrupt comes late, during probe error path or device remove
(could be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler
dspi_interrupt() will access registers with the clock being disabled.
This leads to external abort on non-linefetch on Toradex Colibri VF50
module (with Vybrid VF5xx):

$ echo 4002d000.spi > /sys/devices/platform/soc/40000000.bus/4002d000.spi/driver/unbind

Unhandled fault: external abort on non-linefetch (0x1008) at 0x8887f02c
Internal error: : 1008 [#1] ARM
Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
Backtrace:
(regmap_mmio_read32le)
(regmap_mmio_read)
(_regmap_bus_reg_read)
(_regmap_read)
(regmap_read)
(dspi_interrupt)
(free_irq)
(devm_irq_release)
(release_nodes)
(devres_release_all)
(device_release_driver_internal)

The resource-managed framework should not be used for shared interrupt
handling, because the interrupt handler might be called after releasing
other resources and disabling clocks.

Similar bug could happen during suspend - the shared interrupt handler
could be invoked after suspending the device. Each device sharing this
interrupt line should disable the IRQ during suspend so handler will be
invoked only in following cases:
1. None suspended,
2. All devices resumed.

Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200622110543.5035-3-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix lockup if device is shutdown during SPI transfer

During shutdown, the driver should unregister the SPI controller
and stop the hardware. Otherwise the dspi_transfer_one_message() could
wait on completion infinitely.

Additionally, calling spi_unregister_controller() first in device
shutdown reverse-matches the probe function, where SPI controller is
registered at the end.

Fixes: dc234825997e ("spi: spi-fsl-dspi: Adding shutdown hook")
Reported-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200622110543.5035-2-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix lockup if device is removed during SPI transfer

During device removal, the driver should unregister the SPI controller
and stop the hardware. Otherwise the dspi_transfer_one_message() could
wait on completion infinitely.

Additionally, calling spi_unregister_controller() first in device
removal reverse-matches the probe function, where SPI controller is
registered at the end.

Fixes: 05209f457069 ("spi: fsl-dspi: add missing clk_disable_unprepare() in dspi_remove()")
Reported-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200622110543.5035-1-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Free DMA memory with matching function

Driver allocates DMA memory with dma_alloc_coherent() but frees it with
dma_unmap_single().

This causes DMA warning during system shutdown (with DMA debugging) on
Toradex Colibri VF50 module:

WARNING: CPU: 0 PID: 1 at ../kernel/dma/debug.c:1036 check_unmap+0x3fc/0xb04
DMA-API: fsl-edma 40098000.dma-controller: device driver frees DMA memory with wrong function
[device address=0x0000000087040000] [size=8 bytes] [mapped as coherent] [unmapped as single]
Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
(unwind_backtrace) from [<8010bb34>] (show_stack+0x10/0x14)
(show_stack) from [<8011ced8>] (__warn+0xf0/0x108)
(__warn) from [<8011cf64>] (warn_slowpath_fmt+0x74/0xb8)
(warn_slowpath_fmt) from [<8017d170>] (check_unmap+0x3fc/0xb04)
(check_unmap) from [<8017d900>] (debug_dma_unmap_page+0x88/0x90)
(debug_dma_unmap_page) from [<80601d68>] (dspi_release_dma+0x88/0x110)
(dspi_release_dma) from [<80601e4c>] (dspi_shutdown+0x5c/0x80)
(dspi_shutdown) from [<805845f8>] (device_shutdown+0x17c/0x220)
(device_shutdown) from [<80143ef8>] (kernel_restart+0xc/0x50)
(kernel_restart) from [<801441cc>] (__do_sys_reboot+0x18c/0x210)
(__do_sys_reboot) from [<80100060>] (ret_fast_syscall+0x0/0x28)
DMA-API: Mapped at:
dma_alloc_attrs+0xa4/0x130
dspi_probe+0x568/0x7b4
platform_drv_probe+0x6c/0xa4
really_probe+0x208/0x348
driver_probe_device+0x5c/0xb4

Fixes: 90ba37033cb9 ("spi: spi-fsl-dspi: Add DMA support for Vybrid")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1591803717-11218-1-git-send-email-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: fix native data copy

ColdFire is a big-endian cpu with a big-endian dspi hw module,
so, it uses native access, but memcpy breaks the endianness.

So, if i understand properly, by native copy we would mean
be(cpu)->be(dspi) or le(cpu)->le(dspi) accesses, so my fix
shouldn't break anything, but i couldn't test it on LS family,
so every test is really appreciated.

Fixes: 53fadb4d90c7 ("spi: spi-fsl-dspi: Simplify bytes_per_word gymnastics")
Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200529195756.184677-1-angelo.dureghello@timesys.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Adding shutdown hook

We need to ensure dspi controller could be stopped in order for kexec
to start the next kernel.
So add the shutdown operation support.

Signed-off-by: Peng Ma <peng.ma@nxp.com>
Link: https://lore.kernel.org/r/20200424061216.27445-1-peng.ma@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Add support for LS1028A

This is similar to the DSPI instantiation on LS1028A, except that:
- The A-011218 erratum has been fixed, so DMA works
- The endianness is different, which has implications on XSPI mode

Some benchmarking with the following command:

spidev_test --device /dev/spidev2.0 --bpw 8 --size 256 --cpha --iter 10000000 --speed 20000000

shows that in DMA mode, it can achieve around 2400 kbps, and in XSPI
mode, the same command goes up to 4700 kbps. This is somewhat to be
expected, since the DMA buffer size is extremely small at 8 bytes, the
winner becomes whomever can prepare the buffers for transmission
quicker, and DMA mode has higher overhead there. So XSPI FIFO mode has
been chosen as the operating mode for this chip.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Move invariant configs out of dspi_transfer_one_message

The operating mode (DMA, XSPI, EOQ) is not going to change across the
lifetime of the device. So it makes no sense to keep writing to SPI_RSER
on each message. Move this configuration to dspi_init instead.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix interrupt-less DMA mode taking an XSPI code path

Interrupts are not necessary for DMA functionality, since the completion
event is provided by the DMA driver.

But if the driver fails to request the IRQ defined in the device tree,
it will call dspi_poll which would make the driver hang waiting for data
to become available in the RX FIFO.

Fixes: c55be3059159 ("spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Avoid NULL pointer in dspi_slave_abort for non-DMA mode

The driver does not create the dspi->dma structure unless operating in
DSPI_DMA_MODE, so it makes sense to check for that.

Fixes: f4b323905d8b ("spi: Introduce dspi_slave_abort() function for NXP's dspi SPI driver")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-8-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion

Currently the driver puts the process in interruptible sleep waiting for
the interrupt train to finish transfer to/from the tx_buf and rx_buf.

But exiting the process with ctrl-c may make the kernel panic: the
wait_event_interruptible call will return -ERESTARTSYS, which a proper
driver implementation is perhaps supposed to handle, but nonetheless
this one doesn't, and aborts the transfer altogether.

Actually when the task is interrupted, there is still a high chance that
the dspi_interrupt is still triggering. And if dspi_transfer_one_message
returns execution all the way to the spi_device driver, that can free
the spi_message and spi_transfer structures, leaving the interrupts to
access a freed tx_buf and rx_buf.

hexdump -C /dev/mtd0
00000000 00 75 68 75 0a ff ff ff ff ff ff ff ff ff ff ff
|.uhu............|
00000010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
|................|
*
^C[ 38.495955] fsl-dspi 2120000.spi: Waiting for transfer to complete failed!
[ 38.503097] spi_master spi2: failed to transfer one message from queue
[ 38.509729] Unable to handle kernel paging request at virtual address ffff800095ab3377
[ 38.517676] Mem abort info:
[ 38.520474] ESR = 0x96000045
[ 38.523533] EC = 0x25: DABT (current EL), IL = 32 bits
[ 38.528861] SET = 0, FnV = 0
[ 38.531921] EA = 0, S1PTW = 0
[ 38.535067] Data abort info:
[ 38.537952] ISV = 0, ISS = 0x00000045
[ 38.541797] CM = 0, WnR = 1
[ 38.544771] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000082621000
[ 38.551494] [ffff800095ab3377] pgd=00000020fffff003, p4d=00000020fffff003, pud=0000000000000000
[ 38.560229] Internal error: Oops: 96000045 [#1] PREEMPT SMP
[ 38.565819] Modules linked in:
[ 38.568882] CPU: 0 PID: 2729 Comm: hexdump Not tainted 5.6.0-rc4-next-20200306-00052-gd8730cdc8a0b-dirty #193
[ 38.578834] Hardware name: Kontron SMARC-sAL28 (Single PHY) on SMARC Eval 2.0 carrier (DT)
[ 38.587129] pstate: 20000085 (nzCv daIf -PAN -UAO)
[ 38.591941] pc : ktime_get_real_ts64+0x3c/0x110
[ 38.596487] lr : spi_take_timestamp_pre+0x40/0x90
[ 38.601203] sp : ffff800010003d90
[ 38.604525] x29: ffff800010003d90 x28: ffff80001200e000
[ 38.609854] x27: ffff800011da9000 x26: ffff002079c40400
[ 38.615184] x25: ffff8000117fe018 x24: ffff800011daa1a0
[ 38.620513] x23: ffff800015ab3860 x22: ffff800095ab3377
[ 38.625841] x21: 000000000000146e x20: ffff8000120c3000
[ 38.631170] x19: ffff0020795f6e80 x18: ffff800011da9948
[ 38.636498] x17: 0000000000000000 x16: 0000000000000000
[ 38.641826] x15: ffff800095ab3377 x14: 0720072007200720
[ 38.647155] x13: 0720072007200765 x12: 0775076507750771
[ 38.652483] x11: 0720076d076f0772 x10: 0000000000000040
[ 38.657812] x9 : ffff8000108e2100 x8 : ffff800011dcabe8
[ 38.663139] x7 : 0000000000000000 x6 : ffff800015ab3a60
[ 38.668468] x5 : 0000000007200720 x4 : ffff800095ab3377
[ 38.673796] x3 : 0000000000000000 x2 : 0000000000000ab0
[ 38.679125] x1 : ffff800011daa000 x0 : 0000000000000026
[ 38.684454] Call trace:
[ 38.686905] ktime_get_real_ts64+0x3c/0x110
[ 38.691100] spi_take_timestamp_pre+0x40/0x90
[ 38.695470] dspi_fifo_write+0x58/0x2c0
[ 38.699315] dspi_interrupt+0xbc/0xd0
[ 38.702987] __handle_irq_event_percpu+0x78/0x2c0
[ 38.707706] handle_irq_event_percpu+0x3c/0x90
[ 38.712161] handle_irq_event+0x4c/0xd0
[ 38.716008] handle_fasteoi_irq+0xbc/0x170
[ 38.720115] generic_handle_irq+0x2c/0x40
[ 38.724135] __handle_domain_irq+0x68/0xc0
[ 38.728243] gic_handle_irq+0xc8/0x160
[ 38.732000] el1_irq+0xb8/0x180
[ 38.735149] spi_nor_spimem_read_data+0xe0/0x140
[ 38.739779] spi_nor_read+0xc4/0x120
[ 38.743364] mtd_read_oob+0xa8/0xc0
[ 38.746860] mtd_read+0x4c/0x80
[ 38.750007] mtdchar_read+0x108/0x2a0
[ 38.753679] __vfs_read+0x20/0x50
[ 38.757002] vfs_read+0xa4/0x190
[ 38.760237] ksys_read+0x6c/0xf0
[ 38.763471] __arm64_sys_read+0x20/0x30
[ 38.767319] el0_svc_common.constprop.3+0x90/0x160
[ 38.772125] do_el0_svc+0x28/0x90
[ 38.775449] el0_sync_handler+0x118/0x190
[ 38.779468] el0_sync+0x140/0x180
[ 38.782793] Code: 91000294 1400000f d50339bf f9405e80 (f90002c0)
[ 38.788910] ---[ end trace 55da560db4d6bef7 ]---
[ 38.793540] Kernel panic - not syncing: Fatal exception in interrupt
[ 38.799914] SMP: stopping secondary CPUs
[ 38.803849] Kernel Offset: disabled
[ 38.807344] CPU features: 0x10002,20006008
[ 38.811451] Memory Limit: none
[ 38.814513] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

So it is clear that the "interruptible" part isn't handled correctly.
When the process receives a signal, one could either attempt a clean
abort (which appears to be difficult with this hardware) or just keep
restarting the sleep until the wait queue really completes. But checking
in a loop for -ERESTARTSYS is a bit too complicated for this driver, so
just make the sleep uninterruptible, to avoid all that nonsense.

The wait queue was actually restructured as a completion, after polling
other drivers for the most "popular" approach.

Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform")
Reported-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Protect against races on dspi->words_in_flight

dspi->words_in_flight is a variable populated in the *_write functions
and used in the dspi_fifo_read function. It is also used in
dspi_fifo_write, immediately after transmission, to update the
message->actual_length variable used by higher layers such as spi-mem
for integrity checking.

But it may happen that the IRQ which calls dspi_fifo_read to be
triggered before the updating of message->actual_length takes place. In
that case, dspi_fifo_read will decrement dspi->words_in_flight to -1,
and that will cause an invalid modification of message->actual_length.

For that, we make the simplest fix possible: to not decrement the actual
shared variable in dspi->words_in_flight from dspi_fifo_read, but
actually a copy of it which is on stack.

But even if dspi_fifo_read from the next IRQ does not interfere with the
dspi_fifo_write of the current chunk, the *next* dspi_fifo_write still
can. So we must assume that everything after the last write to the TX
FIFO can be preempted by the "TX complete" IRQ, and the dspi_fifo_write
function must be safe against that. This means refactoring the 2
flavours of FIFO writes (for EOQ and XSPI) such that the calculation of
the number of words to be written is common and happens a priori. This
way, the code for updating the message->actual_length variable works
with a copy and not with the volatile dspi->words_in_flight.

After some interior debate, the dspi->progress variable used for
software timestamping was *not* backed up against preemption in a copy
on stack. Because if preemption does occur between
spi_take_timestamp_pre and spi_take_timestamp_post, there's really no
point in trying to save anything. The first-in-time
spi_take_timestamp_post call with a dspi->progress higher than the
requested xfer->ptp_sts_word_post will trigger xfer->timestamped = true
anyway and will close the deal.

To understand the above a bit better, consider a transfer with
xfer->ptp_sts_word_pre = xfer->ptp_sts_word_post = 3, and
xfer->bits_per_words = 8 (so byte 3 needs to be timestamped). The DSPI
controller timestamps in chunks of 4 bytes at a time, and preemption
occurs in the middle of timestamping the first chunk:

spi_take_timestamp_pre(0)
.
. (preemption)
.
. spi_take_timestamp_pre(4)
.
. spi_take_timestamp_post(7)
.
spi_take_timestamp_post(3)

So the reason I'm not bothering to back up dspi->progress for that
spi_take_timestamp_post(3) is that spi_take_timestamp_post(7) is going
to (a) be more honest, (b) provide better accuracy and (c) already
render the spi_take_timestamp_post(3) into a noop by setting
xfer->timestamped = true anyway.

Fixes: d59c90a2400f ("spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode")
Reported-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Avoid reading more data than written in EOQ mode

If dspi->words_in_flight is populated with the hardware FIFO size,
then in dspi_fifo_read it will attempt to read more data at the end of a
buffer that is not a multiple of 16 bytes in length. It will probably
time out attempting to do so.

So limit the num_fifo_entries variable to the actual number of FIFO
entries that is going to be used.

Fixes: d59c90a2400f ("spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix bits-per-word acceleration in DMA mode

In DMA mode, dspi_setup_accel does not get called, which results in the
dspi->oper_word_size variable (which is used by dspi_dma_xfer) to not be
initialized properly.

Because oper_word_size is zero, a few calculations end up being
incorrect, and the DMA transfer eventually times out instead of sending
anything on the wire.

Set up native transfers (or 8-on-16 acceleration) using dspi_setup_accel
for DMA mode too.

Also take the opportunity and simplify the DMA buffer handling a little
bit.

Fixes: 6c1c26ecd9a3 ("spi: spi-fsl-dspi: Accelerate transfers using larger word size if possible")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix little endian access to PUSHR CMD and TXDATA

In XSPI mode, the 32-bit PUSHR register can be written to separately:
the higher 16 bits are for commands and the lower 16 bits are for data.

This has nicely been hacked around, by defining a second regmap with a
width of 16 bits, and effectively splitting a 32-bit register into 2
16-bit ones, from the perspective of this regmap_pushr.

The problem is the assumption about the controller's endianness. If the
controller is little endian (such as anything post-LS1046A), then the
first 2 bytes, in the order imposed by memory layout, will actually hold
the TXDATA, and the last 2 bytes will hold the CMD.

So take the controller's endianness into account when performing split
writes to PUSHR. The obvious and simple solution would have been to call
regmap_get_val_endian(), but that is an internal regmap function and we
don't want to change regmap just for this. Therefore, we just re-read
the "big-endian" device tree property.

Fixes: 58ba07ec79e6 ("spi: spi-fsl-dspi: Add support for XSPI mode registers")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Don't access reserved fields in SPI_MCR

The SPI_MCR_PCSIS macro assumes that the controller has a number of chip
select signals equal to 6. That is not always the case, but actually is
described through the driver-specific "spi-num-chipselects" device tree
binding. LS1028A for example only has 4 chip selects.

Don't write to the upper bits of the PCSIS field, which are reserved in
the reference manual.

Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200318001603.9650-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: fix DMA mapping

Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.

The error messages look like:
[ 3.008452] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8
[ 3.020123] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8

This was tested on a custom board with a LS1028A SoC.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200310073313.21277-1-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Make bus-num property optional

The SPI bus number is completely optional to Linux, so make the
corresponding device tree property optional as well.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20200305115546.31814-1-s.hauer@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Take software timestamp in dspi_fifo_write

Although the SPI system timestamps are supposed to reflect the moment
that the peripheral has received a word rather than the moment when the
CPU has enqueued that word to the FIFO, in practice it is easier to just
record the latter time than the former (with a smaller error).

With the recent migration of TCFQ users from poll back to interrupt mode
(this time for XSPI FIFO), it's wiser to keep the interrupt latency
outside of the measurement of the PTP system timestamp itself. If there
proves to be any constant offset that requires static compensation, that
can always be added later. So far that does not appear to be the case at
least on the LS1021A-TSN board, where testing shows that the phc2sys
offset is able to remain within +/- 200 ns even after 68 hours of
testing.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-13-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use EOQ for last word in buffer even for XSPI mode

The EOQ mode has a hardware limitation in that it stops the transmission
(including the deassertion of the chip select signal) once the host CPU
requests end-of-queue for a particular word in the TX FIFO.

And XSPI mode has a limitation in that we need a separate CMD FIFO entry
for the last byte in the buffer, where the chip select signal needs to
be deasserted. It's not a functional limitation, but it's rather clunky
and the fact that we need to halt the pipeline and write a single entry
to the TX FIFO whenever a buffer ends brings the throughput down when
transmitting small buffers.

So the idea here is to use EOQ's limitation in our favor when using XSPI
mode. Stop special-casing that final word in the buffer, and just kill
the chip select signal by issuing an EOQ for that last word. Now it can
be mixed in with all the other words in the current TX FIFO train.

A small trick here is that we still keep using the XSPI-specific
signaling via the CMDTCFQ interrupt in RSER, and not enabling the EOQ
interrupt, in order to avoid hardware weirdness (potential races with
separate interrupts being raised for CMDTCFQ and EOQ for what is in fact
the end of the same transmission). That is just theoretical, but it's
good to be cautious, and the EOQ interrupt isn't needed.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-12-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Optimize dspi_setup_accel for lowest interrupt count

Currently, a SPI transfer that is not multiple of the highest supported
word width (e.g. 4 bytes) will be transmitted as follows (assume a
30-byte buffer transmitted through a 32-bit wide FIFO that is 32 bytes
deep):

- First 28 bytes are sent as 7 words of 32 bits each
- Last 2 bytes are sent as 1 word of 16 bits size

But if the dspi_setup_accel function had decided to use a lower
oper_bits_per_word value (16 instead of 32), there would have been
enough space in the TX FIFO to fit the entire buffer in one go (15 words
of 16 bits each).

What we're actually trying to avoid is mixing word sizes within the same
run with the TX FIFO, since there is an erratum surrounding this, and
invalid data might get transmitted.

So this patch adds special cases for when the remaining length of the
buffer can be sent in one go as 8-bit or 16-bit words, otherwise it
falls back to the standard logic of sending as many bytes as possible at
the highest oper_bits_per_word value possible.

The benefit is that there will be one less CMDFQ/EOQ interrupt to
service when the entire buffer is transmitted during a single go, and
that will improve the overall latency of the transfer.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Accelerate transfers using larger word size if possible

This patch adds logic in the driver to transmit SPI buffers that use
bits_per_word=8 with a higher bits_per_word count (multiple of 8).

Currently the following (most common) modes are implemented:
- 8 bits_per_word on 32-bit capable controllers
- 8 bits_per_word on 16-bit capable controllers
- 16 bits_per_word on 32-bit capable controllers

Transfers which are not accelerated are transferred with a hardware
bits_per_word value equal to the one of the SPI transfer.

The difference from just extending bits_per_word=32 at the spi_device
driver level is that endianness is different - the SPI core wants to
treat bits_per_word=32 buffers as arrays of u32 (i.e. words in host CPU
endianness). So to preserve endianness when clumping 8x4 bits into
32-bit words, one must perform conversion between CPU and standard (big)
endianness.

All appearances (both on the wire as well as in the buffers presented to
the peripheral driver) are preserved, just that accesses to the PUSHR
and POPR registers are now more efficient, since the same number of
reads/writes can now carry more data (2x more data on TX, 4x more data
on RX).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode

The Transfer Complete Flag (TCF) interrupt gets raised after each write
to the TX FIFO (PUSHR) which means that it is not possible to devise a
transfer procedure that makes full utilization of the FIFO depth (4
entries on most controllers, 16 entries on some).

On the other hand, XSPI mode has a feature called "command cycling",
which allows a single TX command to be run for a pre-specified number of
TX words. When the command cycle ends, the Command Transfer Complete
Flag bit asserts and raises an interrupt. The advantage in this mode is
that the TX FIFO can be better utilized (more words can be batched at
once).

Other changes brought by this patch:
- The dspi->rx_end variable has been removed, since now the
dspi_fifo_write function sets up dspi->words_in_flight, so
dspi_fifo_read knows how much to read without overrunning the RX
buffer.
- Stop using poll mode unconditionally for TCFQ mode, since XSPI mode
is a little less efficient than that, and so, poll mode doesn't bring
as many improvements for XSPI.
- Stop relying on the hardware transfer counter (SPI_TCR_GET_TCNT) and
instead increment the message->actual_length based on the newly
introduced dspi->words_in_flight variable.
- The CTARE register is now written in the hotpath instead of just at
transfer init time, since it contains the DTCP field (transfer
preload - the counter indicating how many txdata words will follow),
which is a dynamic value.

Due to the fact that the Chip Select toggling setting is part of the
command written to the TX FIFO, the ending word of each buffer needs to
be sent via its own TX command, so that we have a chance to emit a
1-word command with deasserted PCS.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Implement .max_message_size method for EOQ mode

When it gets set, End Of Queue Flag halts the DSPI controller and forces
the chip select signal to deassert.

This operating mode is not ideal, but it is used for the DSPI
instantiations where there is no other notification from the controller
that the data in the FIFO has finished transmission. So in practice, it
means that transmitting buffers larger than the FIFO size will yield
unpredictable results.

The only controller that operates in EOQ mode is MCF5441X (Coldfire). I
would say that the way EOQ is used (and documented in the reference
manual, too) on this chip is incorrect, and I would personally migrate
it to TCFQ, but that's notably worse in terms of performance (it can
only use 1 entry of the 16-deep FIFO) and if this limitation didn't
bother any Coldfire DSPI user so far, it's likely that we just need to
throw an error for larger buffers to make sure that callers are aware
their transfers are getting truncated/split.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Rename fifo_{read,write} and {tx,cmd}_fifo_write

These function names are very generic and it is easy to get confused.
Rename them after the hardware register that they are accessing.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Add comments around dspi_pop_tx and dspi_push_rx functions

Their names are confusing, since dspi_pop_tx prepares a word to be
written to the PUSHR register, and dspi_push_rx gets a word from the
POPR register.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Don't mask off undefined bits

This is a useless operation, and if the driver needs to do that, there's
something deeply wrong going on.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove unused chip->void_write_data

This variable has been present since the initial submission of the
driver, and held, for some reason, the value of zero, to be sent on the
wire in the case there wasn't any TX buffer for the current transfer.

Since quite a while now, however, it isn't doing anything at all.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Simplify bytes_per_word gymnastics

Reduce the if-then-else-if-then-else sequence to:
- a simple division in the case of bytes_per_word calculation
- a memcpy command with a variable size. The semantics of larger-than-8
xfer->bits_per_word is that those words are to be interpreted and
transmitted in CPU native endianness.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Convert the instantiations that support it to DMA

The A-011218 eDMA/DSPI erratum affects most of the older Layerscape SoCs
with DSPI, and its workaround is a bit intrusive.

After this patch, there are no users of TCFQ mode that don't also
support XSPI (previously there was LS2085A).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-7-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Support SPI software timestamping in all non-DMA modes

There's no reason to keep this .ptp_sts_supported property explicitly in
devtype_data, since it can be deduced from the operating mode alone.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-6-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: LS2080A and LX2160A support XSPI mode

XSPI allows for 2 extra features:
- Command cycling (use a single TX command with more than 1 word in the
TX FIFO).
- Increased word size (from 16 bits to 32 bits)

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-5-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Parameterize the FIFO size and DMA buffer size

Get rid of the ifdef for Coldfire and make these hardware
characteristics part of dspi->devtype_data.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-4-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use specific compatible strings for all SoC instantiations

Currently, the device tree bindings submitted in mainline for Layerscape
SoCs look like this:

LS1021A:
compatible = "fsl,ls1021a-v1.0-dspi";

LS1012A:
compatible = "fsl,ls1012a-dspi", "fsl,ls1021a-v1.0-dspi";

LS2085A:
compatible = "fsl,ls2085a-dspi";

LS2088A:
compatible = "fsl,ls2080a-dspi", "fsl,ls2085a-dspi";

LX2160A:
compatible = "fsl,lx2160a-dspi", "fsl,ls2085a-dspi";

LS1043A:
compatible = "fsl,ls1043a-dspi", "fsl,ls1021a-v1.0-dspi";

LS1046A:
compatible = "fsl,ls1021a-v1.0-dspi";

Due to a lack of a more specific compatible string, LS1012A, LS1043A and
LS1046A will fall under the LS1021A umbrella, and LS2088A and LX2160A
under the LS2085A umbrella.

They do work in those modes, but there are slight differences in the
hardware instantiations, mostly related to FIFO sizes (with the more
specific compatible strings, the FIFO size can be increased properly).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-3-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix 16-bit word order in 32-bit XSPI mode

When used in Extended SPI mode on LS1021A, the DSPI controller wants to
have the least significant 16-bit word written first to the TX FIFO.

In fact, the LS1021A reference manual says:

33.5.2.4.2 Draining the TX FIFO

When Extended SPI Mode (DSPIx_MCR[XSPI]) is enabled, if the frame size
of SPI Data to be transmitted is more than 16 bits, then it causes two
Data entries to be popped from TX FIFO simultaneously which are
transferred to the shift register. The first of the two popped entries
forms the 16 least significant bits of the SPI frame to be transmitted.

So given the following TX buffer:

+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 0x0 | 0x1 | 0x2 | 0x3 | 0x4 | 0x5 | 0x6 | 0x7 | 0x8 | 0x9 | 0xa | 0xb |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 32-bit word 1 | 32-bit word 2 | 32-bit word 3 |
+-----------------------+-----------------------+-----------------------+

The correct way that a little-endian system should transmit it on the
wire when bits_per_word is 32 is:

0x03020100
0x07060504
0x0b0a0908

But it is actually transmitted as following, as seen with a scope:

0x01000302
0x05040706
0x09080b0a

It appears that this patch has been submitted at least once before:
https://lkml.org/lkml/2018/9/21/286
but in that case Chuanhua Han did not manage to explain the problem
clearly enough and the patch did not get merged, leaving XSPI mode
broken.

Fixes: 8fcd151d2619 ("spi: spi-fsl-dspi: XSPI FIFO handling (in TCFQ mode)")
Cc: Esben Haabendal <eha@deif.com>
Cc: Chuanhua Han <chuanhua.han@nxp.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191228135536.14284-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: Don't look at TX buffer for PTP system timestamping

The API for PTP system timestamping (associating a SPI transaction with
the system time at which it was transferred) is flawed: it assumes that
the xfer->tx_buf pointer will always be present.

This is, of course, not always the case.

So introduce a "progress" variable that denotes how many word have been
transferred.

Fix the Freescale DSPI driver, the only user of the API so far, in the
same patch.

Fixes: b42faeee718c ("spi: Add a PTP system timestamp to the transfer structure")
Fixes: d6b71dfaeeba ("spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191227012417.1057-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20191212135550.4634-8-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: use new `spi_transfer_delay_exec` helper where straightforward

For many places in the spi drivers, using the new `spi_transfer_delay`
helper is straightforward.
It's just replacing:
```
if (t->delay_usecs)
udelay(t->delay_usecs);
```
with `spi_transfer_delay(t)` which handles both `delay_usecs` and the new
`delay` field.

This change replaces in all places (in the spi drivers) where this change
is simple.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-10-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Always use the TCFQ devices in poll mode

With this patch, the "interrupts" property from the device tree bindings
is ignored, even if present, if the driver runs in TCFQ mode.

Switching to using the DSPI in poll mode has several distinct
benefits:

- With interrupts, the DSPI driver in TCFQ mode raises an IRQ after each
transmitted word. There is more time wasted for the "waitq" event than
for actual I/O. And the DSPI IRQ count can easily get the largest in
/proc/interrupts on Freescale boards with attached SPI devices.

- The SPI I/O time is both lower, and more consistently so. Attached to
some Freescale devices are either PTP switches, or SPI RTCs. For
reading time off of a SPI slave device, it is important that all SPI
transfers take a deterministic time to complete.

- In poll mode there is much less time spent by the CPU in hardirq
context, which helps with the response latency of the system, and at
the same time there is more control over when interrupts must be
disabled (to get a precise timestamp measurement): win-win.

On the LS1021A-TSN board, where the SPI device is a SJA1105 PTP switch
(with a bits_per_word=8 driver), I created a "benchmark" where I read
its PTP time once per second, for 120 seconds. Each "read PTP time" is a
12-byte SPI transfer. I then recorded the time before putting the first
byte in the TX FIFO, and the time after reading the last byte from the
RX FIFO. That is the transfer delay in nanoseconds.

Interrupt mode:

delay: min 125120 max 168320 mean 150286 std dev 17675.3

Poll mode:

delay: min 69440 max 119040 mean 70312.9 std dev 8065.34

Both the mean latency and the standard deviation are more than 50% lower
in poll mode than in interrupt mode. This is with an 'ondemand' governor
on an otherwise idle system - therefore running mostly at 600 MHz out of
a max of 1200 MHz.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode

In this mode, the DSPI controller uses PIO to transfer word by word. In
comparison, in EOQ mode the 4-word deep FIFO is being used, hence the
current logic will need some adaptation for which I do not have the
hardware (Coldfire) to test. It is not clear what is the timing of DMA
transfers and whether timestamping in the driver brings any overall
performance increase compared to regular timestamping done in the core.

Short phc2sys summary after 58 minutes of running on LS1021A-TSN with
interrupts disabled during the critical section:

offset: min -26251 max 16416 mean -21.8672 std dev 863.416
delay: min 4720 max 57280 mean 5182.49 std dev 1607.19
lost servo lock 3 times

Summary of the same phc2sys service running for 120 minutes with
interrupts disabled:

offset: min -378 max 381 mean -0.0083089 std dev 101.495
delay: min 4720 max 5920 mean 5129.38 std dev 154.899
lost servo lock 0 times

The minimum delay (pre to post time) in nanoseconds is the same, but the
maximum delay is quite a bit higher, due to interrupts getting sometimes
executed and interfering with the measurement. Hence set disable_irqs
whenever possible (aka when the driver runs in poll mode - otherwise it
would be a contradiction in terms).

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Always use the TCFQ devices in poll mode

With this patch, the "interrupts" property from the device tree bindings
is ignored, even if present, if the driver runs in TCFQ mode.

Switching to using the DSPI in poll mode has several distinct
benefits:

- With interrupts, the DSPI driver in TCFQ mode raises an IRQ after each
transmitted word. There is more time wasted for the "waitq" event than
for actual I/O. And the DSPI IRQ count can easily get the largest in
/proc/interrupts on Freescale boards with attached SPI devices.

- The SPI I/O time is both lower, and more consistently so. Attached to
some Freescale devices are either PTP switches, or SPI RTCs. For
reading time off of a SPI slave device, it is important that all SPI
transfers take a deterministic time to complete.

- In poll mode there is much less time spent by the CPU in hardirq
context, which helps with the response latency of the system, and at
the same time there is more control over when interrupts must be
disabled (to get a precise timestamp measurement, which will come in a
future patch): win-win.

On the LS1021A-TSN board, where the SPI device is a SJA1105 PTP switch
(with a bits_per_word=8 driver), I created a "benchmark" where I
periodically transferred a 12-byte message once per second, for 120
seconds. I then recorded the time before putting the first byte in the
TX FIFO, and the time after reading the last byte from the RX FIFO. That
is the transfer delay in nanoseconds.

Interrupt mode:

delay: min 125120 max 168320 mean 150286 std dev 17675.3

Poll mode:

delay: min 69440 max 119040 mean 70312.9 std dev 8065.34

Both the mean latency and the standard deviation are more than 50% lower
in poll mode than in interrupt mode, and the 'max' in poll mode is lower
than the 'min' in interrupt mode. This is with an 'ondemand' governor on
an otherwise idle system - therefore running mostly at 600 MHz out of a
max of 1200 MHz.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191001205216.32115-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Introduce dspi_slave_abort() function for NXP's dspi SPI driver

This change provides the dspi_slave_abort() function, which is a callback
for slave_abort() method of SPI controller generic driver.

As in the SPI slave mode the transmission is driven by master, any
distortion may cause the slave to enter undefined internal state.
To avoid this problem the dspi_slave_abort() terminates all pending and
ongoing DMA transactions (with sync) and clears internal FIFOs.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Link: https://lore.kernel.org/r/20190924110547.14770-3-lukma@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix race condition in TCFQ/EOQ interrupt

When the driver is working in TCFQ/EOQ mode (i.e. interacts with the SPI
controller's FIFOs directly) the following sequence of operations
happens:

- The first byte of the tx buffer gets pushed to the TX FIFO (dspi->len
gets decremented). This triggers the train of interrupts that handle
the rest of the bytes.

- The dspi_interrupt handles a TX confirmation event. It reads the newly
available byte from the RX FIFO, checks the dspi->len exit condition,
and if there's more to be done, it kicks off the next interrupt in the
train by writing the next byte to the TX FIFO.

Now the problem is that the wait queue is woken up one byte too early,
because dspi->len becomes 0 as soon as the byte has been pushed into the
TX FIFO. Its interrupt has not yet been processed and the RX byte has
not been put from the FIFO into the buffer.

Depending on the timing of the wait queue wakeup vs the handling of the
last dspi_interrupt, it can happen that the main SPI message pump thread
has already returned back into the spi_device driver. When the rx buffer
is on stack (which it can be, because in this mode, the DSPI doesn't do
DMA), the last interrupt will perform a memory write into an rx buffer
that has been freed. This manifests as stack corruption.

The solution is to only wake up the wait queue when dspi_rxtx says so,
i.e. after it has processed the last TX confirmation interrupt and
collected the last RX byte.

Fixes: c55be3059159 ("spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190903105708.32273-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing

On platforms like LS1021A which use TCFQ mode, an interrupt needs to be
processed after each byte is TXed/RXed. I tried to make the DSPI
implementation on this SoC operate in other, more efficient modes (EOQ,
DMA) but it looks like it simply isn't possible.

Therefore allow the driver to operate in poll mode, to ease a bit of
this absurd amount of IRQ load generated in TCFQ mode. Doing so reduces
both the net time it takes to transmit a SPI message, as well as the
inter-frame jitter that occurs while doing so.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove impossible to reach error check

dspi->devtype_data is under the total control of the driver. Therefore,
a bad value is a driver bug and checking it at runtime (and during an
ISR, at that!) is pointless.

The second "else if" check is only for clarity (instead of a broader
"else") in case other transfer modes are added in the future. But the
printing is dead code and can be removed.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Exit the ISR with IRQ_NONE when it's not ours

The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.

Fixes: 13aed2392741 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Reduce indentation level in dspi_interrupt

If the entire function depends on the SPI status register having the
interrupt bits asserted, then just check it and exit early if those bits
aren't set (such as in the case of the shared IRQ being triggered for
the other peripheral). Cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Exit the ISR with IRQ_NONE when it's not ours

The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.

Fixes: 13aed2392741 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822212450.21420-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: spi-fsl-dspi: Move dspi_interrupt above dspi_transfer_one_message

The two functions are loosely coupled through dspi->waitq, but
logically, dspi_transfer_one_message depends on dspi_interrupt in order
to complete. Move its definition above it so the I/O functions are
grouped closer together.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-13-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix typos

mask of -> mask off
at and -> and

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-12-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use reverse Christmas tree declaration order

This patch puts variable declaration in the reverse order of their
length for cosmetic purposes.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Replace legacy spi_master names with spi_controller

This adapts the spi-fsl-dspi driver to the API changes introduced in
commit 8caab75fd2c2 ("spi: Generalize SPI "master" to "controller"").

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove pointless assignment of master->transfer to NULL

Introduced in commit 9298bc727385 ("spi: spi-fsl-dspi: Remove
spi-bitbang") for less than obvious reasons, this assignment is
confusing and serves no purpose.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove unused initialization of 'ret' in dspi_probe

There is no code path for reaching 'return ret;' without it first being
assigned to an error code. Therefore the initialization with 0 is
pointless.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-8-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Reduce indentation in dspi_release_dma()

There is no point in surrounding an entire function block in an if
condition. Rather, exit early if the condition is false.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Change usage pattern of SPI_MCR_* and SPI_CTAR_* macros

These are macros that accept 0 or 1 as argument (a boolean value). Their
use encourages the abuse of complex ternary operations inside their
argument list, which detracts from the code readability. Replace these
with simple if-else statements.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Demistify magic value in SPI_SR_CLEAR

This patch adds the field definitions for the SPI_SR register. The SPI
status register is write-1-to-clear and this value is written at init
time.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use BIT() and GENMASK() macros

Switch to using more idiomatic register field definitions, which makes
it easier to look them up in the datasheet. Cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove unused defines and includes

This is a cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix code alignment

This is a cosmetic patch that changes nothing except makes sure the code
is aligned to the same column, which makes it easier to the eye.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-42-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Provide support for DSPI slave mode operation (Vybryd vf610)

The NXP's Vybryd vf610 can work as a SPI slave device (the CS and clock
signals are provided by master).

It is possible to specify a single device to work in that mode. As we do
use DMA for transferring data, the RX channel must be prepared for
incoming data.
Moreover, in slave mode we just set a subset of control fields in
configuration registers (CTAR0, PUSHR).

For testing the spidev_test program has been used.
Test script for this patch can be found here:
https://github.com/lmajewski/tests-spi/blob/master/tests/spi/spi_tests.sh

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix initial SPI_SR value in spi-fsl-dspi

On ColdFire mcf54418, using DSPI_DMA_MODE mode, spi transfers
at first boot stage are not succeding:

m25p80 spi0.1: unrecognized JEDEC id bytes: 00, 00, 00

The reason is the SPI_SR initial value set by the driver, that
is not clearing (not setting to 1) the RF_DF flag. After a tour
on the dspi hw modules that use this driver(Vybrid, ColdFire and
ls1021a) a better init value for SR register has been set.

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ

Some SoC share one irq number between DSPI controllers.
For example, on the LX2160 board, DSPI0 and DSPI1 share one irq number.
In this case, only one DSPI controller can register successfully,
and others will fail.

Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: fix broken DSPI_EOQ_MODE

This patch fixes the dspi_eoq_write function used by the
ColdFire mcf5441x family. The 16 bit cmd part must be re-set at
each data transfer.

Also, now that fifo_size variables are used for eoq_read/write,
a proper fifo size must be set (16 slots for the ColdFire dspi
module version).

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Acked-by: Esben Haabendal <esben@haabendal.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: spi-fsl-dspi: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fill actual_length when doing DMA transfer

Upper layer users of SPI device drivers may rely on 'actual_length',
so it is important that information is correctly reported. One such
example is spi_mem_exec_op() function that will fail if
'actual_length' of the data transferred is not what was requested. Add
necessary code to populate 'actual_length.

Cc: Mark Brown <broonie@kernel.org>
Cc: Sanchayan Maity <maitysanchayan@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: cphealy@gmail.com
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix imprecise abort on VF500 during probe

Registers of DSPI should not be accessed before enabling its clock. On
Toradex Colibri VF50 on Iris carrier board this could be seen during
bootup as imprecise abort:

Unhandled fault: imprecise external abort (0x1c06) at 0x00000000
Internal error: : 1c06 [#1] ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.14.39-dirty #97
Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
Backtrace:
[<804166a8>] (regmap_write) from [<80466b5c>] (dspi_probe+0x1f0/0x8dc)
[<8046696c>] (dspi_probe) from [<8040107c>] (platform_drv_probe+0x54/0xb8)
[<80401028>] (platform_drv_probe) from [<803ff53c>] (driver_probe_device+0x280/0x2f8)
[<803ff2bc>] (driver_probe_device) from [<803ff674>] (__driver_attach+0xc0/0xc4)
[<803ff5b4>] (__driver_attach) from [<803fd818>] (bus_for_each_dev+0x70/0xa4)
[<803fd7a8>] (bus_for_each_dev) from [<803fee74>] (driver_attach+0x24/0x28)
[<803fee50>] (driver_attach) from [<803fe980>] (bus_add_driver+0x1a0/0x218)
[<803fe7e0>] (bus_add_driver) from [<803fffe8>] (driver_register+0x80/0x100)
[<803fff68>] (driver_register) from [<80400fdc>] (__platform_driver_register+0x48/0x50)
[<80400f94>] (__platform_driver_register) from [<8091cf7c>] (fsl_dspi_driver_init+0x1c/0x20)
[<8091cf60>] (fsl_dspi_driver_init) from [<8010195c>] (do_one_initcall+0x4c/0x174)
[<80101910>] (do_one_initcall) from [<80900e8c>] (kernel_init_freeable+0x144/0x1d8)
[<80900d48>] (kernel_init_freeable) from [<805ff6a8>] (kernel_init+0x10/0x114)
[<805ff698>] (kernel_init) from [<80107be8>] (ret_from_fork+0x14/0x2c)

Cc: <stable@vger.kernel.org>
Fixes: 5ee67b587a2b ("spi: dspi: clear SPI_SR before enable interrupt")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix copy-paste error in dspi_probe

It seems that the proper structure field to use in this particular
case is *regmap_pushr* instead of regmap.

Addresses-Coverity-ID: 1470126 ("Copy-paste error")
Fixes: 58ba07ec79e6 ("spi: spi-fsl-dspi: Add support for XSPI mode registers")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Esben Haabendal <eha@deif.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Enable extended SPI mode

Set the XSPI bit for devices configured for XSPI mode (currently LS1021A),
and thereby switch to extended SPI mode, allowing for SPI transfers using
from 4 to 32 bits per word instead of 4 to 16 bits per word.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Advertise 32 bit for XSPI mode

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: XSPI FIFO handling (in TCFQ mode)

This implements handling of split CMD and TX FIFO queues for XSPI when
running in TCFQ mode.

It should be simple to add it to EOQ mode also. Currently, EOQ mode is
only used with coldfire. So if coldfire DSPI supports XSPI, XSPI FIFO
handling should be added to EOQ mode also.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Framesize control for XSPI mode

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Add support for XSPI mode registers

This prepares for adding support for extended SPI mode (XSPI), by extending
the regmap with the extra SREX and CTAREx registers.

An additional register map is made for allowing 16 bit access to CMD and TX
FIFO of the PUSHR register separately, which is also needed for XSPI mode
support.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fixup regmap configuration

Mark volatile registers to avoid caching bugs.

Note: SPI_MCR is marked volatile because of CLR_TXF and CLR_RXF bits.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix MCR register handling

The MCR register is not changed, so initialize it in dspi_init().

The exception is the CLR_TXF and CLR_RXF bits, which should be written to
before each transfer to make sure we start with empty FIFOs. With MCR
register now configured as volatile, the regmap_update_bits will do a real
read-modify-write cycle.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Support 4 to 16 bits per word transfers

This extends the driver with support for all SPI framesizes from 4 to 16
bits, and adds support for per transfer specific bits_per_word, while at
the same time reducing code size and complexity.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Simplify transfer counter handling

Simplify driver by avoiding counter wrapping by clearing transfer counter
on first SPI transfer per interrupt instead of tracking what it was before.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix per transfer cs_change handling

As of 92dc20d83adec565378254c0630e839ff5674e14, transfer->cs_change has
been supported for non-last transfers, but not for last transfer.

This change brings handling of cs_change in line with the specification in
spi.h, implementing handling of transfer->cs_change for all transfers.

The value for CMD FIFO is precalculated with transfer->cs_change field
taken into account, allowing for CS de-activate between transfers and
keeping CS activated after last transfer.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Drop unneeded use of dataflags bits

Checking directly against pointer value should be at least as fast as doing
bitmasking and compare, so let's keep it simple.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Drop unreachable else if statement

The if statement just above this if/else statement triggers on the same
condition, and then invalidates it.

Signed-off-by: Esben Haabendal <eha@deif.com>
Acked-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: account for const type of of_device_id.data

This driver creates a number of const structures that it stores in the
data field of an of_device_id array.

The data field of an of_device_id structure has type const void *, so
there is no need for a const-discarding cast when putting const values
into such a structure.

Done using Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: add SPI_LSB_FIRST to driver capabilities

The driver as well as the controller support the SPI lsb first
mode. However, it's not possible to configure it e.g. when using
spidev. Adding this flag to mode_bits resolves the issue and lsb first
mode can be used.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: enabling Coldfire mcf5441x dspi

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: ensure non-zero return on error path

Propagate error return from dspi_request_dma() into probe routine's
return.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix error handling

According to error handling in this function, it is likely that going to
'out_master_put' was expected here.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix continuous selection format

Current DMA implementation was not handling the continuous selection
format viz. SPI chip select would be deasserted even between sequential
serial transfers.

Use existing dspi_data_to_pushr function to restructure the transmit
code path and set or reset the CONT bit on same lines as code path
in EOQ mode does. This correctly implements continuous selection format
while also correcting and cleaning up the transmit code path.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix incorrect DMA setup

Currently dmaengine_prep_slave_single was being called with length
set to the complete DMA buffer size. This resulted in unwanted bytes
being transferred to the SPI register leading to clock and MOSI lines
having unwanted data even after chip select got deasserted and the
required bytes having been transferred.

While at it also clean up the use of curr_xfer_len which is central
to the DMA setup, from bytes to DMA transfers for every use.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix incorrect freeing of DMA allocated buffers

Buffers allocated with a call to dma_alloc_coherent should be
freed with dma_free_coherent instead of the currently used
devm_kfree.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix SPI transfer issue when using multiple SPI_IOC_MESSAGE

Current DMA implementation had a bug where the DMA transfer would
exit the loop in dspi_transfer_one_message after the completion of
a single transfer. This results in a multi message transfer submitted
with SPI_IOC_MESSAGE to terminate incorrectly without an error.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Add DMA support for Vybrid

Add DMA support for Vybrid.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: dspi: clear SPI_SR before enable interrupt

Once dspi is used in uboot, the SPI_SR have been set by some value.
At this time, if kernel enable the interrupt before clear the
status flag, that will trigger the wrong interrupt.

Signed-off-by: Yuan Yao <yao.yuan@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Drop extra spi_master_put in device remove function

The call sequence spi_alloc_master/spi_register_master/spi_unregister_master
is complete; it reduces the device reference count to zero, which and results
in device memory being freed. The subsequent call to spi_master_put is
unnecessary and results in an access to free memory. Drop it.

Fixes: 9298bc727385 ("spi: spi-fsl-dspi: Remove spi-bitbang")
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Check clk_prepare_enable() error

clk_prepare_enable() may fail, so we should better check its
return value and propagate it in the case of failure.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: fix a possible NULL dereference

of_match_device could return NULL, and so cause a NULL pointer
dereference later.

For fixing this problem, we use of_device_get_match_data(), this will
simplify the code a little by using a standard function for
getting the match data.

Reported-by: coverity (CID 1324129)
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: constify devtype_data

of_id->data is const, so instead of casting the pointer to drop its
const status, this patch constify the devtype_data pointer.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix cs_change handling in message transfer

There are use cases when chip select should be triggered between transfers
in single SPI message. Current implementation does this only on last
transfer in message ignoring cs_change value provided in current transfer.

Signed-off-by: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Set max_speed_hz for master

Calculate and update max speed from bus clock for SoCs
using DSPI IP.

The bus clock factor's are taken from the data sheets
of respective SoCs.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi-fsl-dspi: Fix CTAR Register access

DSPI instances in Vybrid have a different amount of chip selects
and CTARs (Clock and transfer Attributes Register). In case of
DSPI1 we only have 2 CTAR registers and 4 CS. In present driver
implementation CTAR offset is derived from CS instance which will
lead to out of bound access if chip select instance is greater than
CTAR register instance, hence use single CTAR0 register for all CS
instances. Since we write the CTAR register anyway before each access,
there is no value in using the additional CTAR registers. Also one
should not program a value in CTAS for a CTAR register that is not
present, hence configure CTAS to use CTAR0.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove duplicated register write

SPI core makes sure that transfer speed is always set so code here writes
the same register with the same value twice. Code has been doing this from
the beginning.

This looks to me some sort of copy paste error so I'm removing the second
write. If this is not the case we can bring it back with a comment.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Use pinctrl PM helpers

Add support for "sleep" state of pinctrl.

Signed-off-by: Mirza Krak <mirza.krak@hostmobility.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Change the way of increasing spi_message->actual_length

In current driver, we increase actual_length in the following way:
message->actual_length += dspi_xxx_transfer()
It has two defects.
First, transmitting maybe in process when the function call finished and
we don't know the transmitting result in this moment.
Secondly, the last sentence in function before returning is accessing the
SPI register and trigger the data transmitting. If we enable interrupt,
interrupt may be generated before function return and we also have the same
sentence "message->actual_length += dspi_xxx_transfer()"
in the IRQ handler.
And usually dspi_xxx_transfer will trigger a new IRQ.
The original dspi_xxx_transfer call may return when no new IRQ generate.
This may mess the variable spi_message->actual_length.
Now we increase the variable in the IRQ handler and only when we get the
TCF or EOQ interrupt
And we get the transmitted data length from the SPI transfer counter
instead of the function return value.

Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Enable TCF interrupt mode support

DSPI module has two optional interrupts when complete data transfer.
One is EOQ interrupt, the other one is TCF interrupt.
EOQ indicates a queue of data frame has been transmitted.
TCF indicates a frame has been transmitted.
This patch enable support TCF mode.
Driver binds a correct interrupt mode to every compatible string.
User should use the correct compatible string in the dts node.

Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Bug fix incorrect CS de-assert

SPI chip select signal need to keep asserted between several
spi_transfer in the same spi_message usually.
But the driver will de-assert CS signal and the assert it between
serval spi_transfer in the same spi_message under some condiations.
This patch fix the bug.

Here is an example:
Assume you have two variables like the following,
struct spi_transfer a;
struct spi_transfer b;
if you send a spi_message only includes 'a' first,
and then you send a spi_message includes 'a' and 'b'
but without resetting 'a'.
Driver will de-assert CS and then assert CS between 'a' and 'b'.

Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: remove clk reference when regmap_mmio initialize

It is unnecessary for DSPI to enable/disable clk when access DSPI register.
And it will reduce efficiency.

Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Add ~50ns delay between cs and sck

Add delay between chip select and clock signals, before clock starts and
after clock stops.

Signed-off-by: Aaron Brice <aaron.brice@datasoft.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Fix clock rate scale values

Previous algorithm had an outer loop with the values {2,3,5,7} and an
inner loop with {2,4,6,8,16,32,...,32768}, and would pick the first
value over the required scaling value (where the total scale was the two
numbers multiplied).

Since the inner loop went up to 32768 it would always pick a value of 2
for PBR and a much higher than necessary value for BR. The desired
scale factor was being divided by two I believe to compensate for the
much higher scale factors (the divide by two not specified in the
reference manual).

Updated to check all values and find the smallest scale factor possible
without going over the desired clock rate.

Signed-off-by: Aaron Brice <aaron.brice@datasoft.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Fix clock rate scale values

Previous algorithm had an outer loop with the values {2,3,5,7} and an
inner loop with {2,4,6,8,16,32,...,32768}, and would pick the first
value over the required scaling value (where the total scale was the two
numbers multiplied).

Since the inner loop went up to 32768 it would always pick a value of 2
for PBR and a much higher than necessary value for BR. The desired
scale factor was being divided by two I believe to compensate for the
much higher scale factors (the divide by two not specified in the
reference manual).

Updated to check all values and find the smallest scale factor possible
without going over the desired clock rate.

Signed-off-by: Aaron Brice <aaron.brice@datasoft.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Remove possible memory leak of 'chip'

Move the check for spi->bits_per_word
before allocation, to avoid memory leak.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove spi-bitbang

DSPI module need cs change information in
a spi transfer. According to cs change, DSPI
will give last data the right flag. Bitbang
provide cs change behind the last data in
a transfer. So DSPI can not deal the last
data in every transfer properly, so remove
the bitbang in the driver.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove usage of devm_kzalloc

devm_* API was supposed to be used only in probe function call.
Memory is allocated at 'probe' and free automatically at 'remove'.
Usage of devm_* functions outside probe sometimes leads to memory leak.
Avoid using devm_kzalloc in dspi_setup_transfer and use kzalloc instead.
Also add the dspi_cleanup function to free the controller data upon
cleanup.

Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: fsl-dspi: Fix CTAR selection

There are only 4 CTAR registers (CTAR0 - CTAR3) so we can only use the
lower 2 bits of the chip select to select a CTAR register.
SPI_PUSHR_CTAS used the lower 3 bits which would result in wrong bit values
if the chip selects 4/5 are used. For those chip selects SPI_CTAR even
calculated offsets of non-existing registers.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: fsl-dspi: remove useless code for dspi driver.

Since we are using regmap framework's internal locks, so the
lock_arg for dspi_regmap_config is redundant here.

This patch just remove it, and then the dspi_regmap_config could
be const type.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl: Sort include headers alphabetically

Sort all the include headers alphabetically for the freescale
spi drivers. If the inlcude headers sorted out of order, maybe
the best logical choice is to append new ones after the exist
ones, while this may create a lot of potential for duplicates
and conflicts for each diffenent changes will add new headers
in the same location.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Remove probe info message

Remove the probe info message which also has wrong output. No need to add
KERN_INFO to pr_info. Output was:
6Freescale DSPI master initialized

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-dspi: Convert to use regmap framework's endianness method.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Acked-by: Chao Fu <b44548@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: Make of_device_id array const

Make of_device_id array const, because all OF functions
handle it as const.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: Fix memory leak

The memory allocated for chip is not freed anywhere.
Convert to use devm_kzalloc to fix the memory leak.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: Use SIMPLE_DEV_PM_OPS macro

Use SIMPLE_DEV_PM_OPS macro in order to make the code simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: Fix getting correct address for master

Current code set platform drvdata to dspi. However, the code in dspi_suspend()
and dspi_resume() assumes the drvdata is the address of master.
Fix it by setting platform drvdata to master.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

spi/fsl-dspi: Remove some coding sytle not in standard

Remove some coding sytle not in standard in former code.

Signed-off-by: Chao Fu <b44548@freescale.com>
Reviewed-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi/fsl-dspi: Convert to use regmap and add big-endian support

Freescale DSPI module will have two endianess in different platform,
but ARM is little endian. So when DSPI in big endian, core in little endian,
readl and writel can not adjust R/W register in this condition.
This patch will remove general readl/writel, and import regmap mechanism.
Data endian will be transfered in regmap APIs.

Documents: dspi add bool "big-endian" in dts node if DSPI module
work in big endian.

Signed-off-by: Chao Fu <b44548@freescale.com>
Reviewed-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: Remove duplicate code to set default bits_per_word setting

The implementation in spi_setup() already set spi->bits_per_word = 8 when
spi->bits_per_word is 0 before calling spi->master->setup.
So we don't need to do it again in setup() callback.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: Add missing breaks for switch cases

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: add missing clk_disable_unprepare() in dspi_remove()

clock source is prepared and enabled by clk_prepare_enable()
in probe function, but no disable or unprepare in remove.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: bitbang: Let spi_bitbang_start() take a reference to master

Many drivers that use bitbang library have a leak on probe error paths.
This is because once a spi_master_get() call succeeds, we need an additional
spi_master_put() call to free the memory.

Fix this issue by moving the code taking a reference to master to
spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on
success. With this change, the caller is responsible for calling
spi_bitbang_stop() to decrement the reference and spi_master_put() as
counterpart of spi_alloc_master() to prevent a memory leak.

So now we have below patten for drivers using bitbang library:

probe:
spi_alloc_master -> Init reference count to 1
spi_bitbang_start -> Increment reference count
remove:
spi_bitbang_stop -> Decrement reference count
spi_master_put -> Decrement reference count (reference count reaches 0)

Fixup all users accordingly.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: bitbang: Let spi_bitbang_start() take a reference to master

Many drivers that use bitbang library have a leak on probe error paths.
This is because once a spi_master_get() call succeeds, we need an additional
spi_master_put() call to free the memory.

Fix this issue by moving the code taking a reference to master to
spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on
success. With this change, the caller is responsible for calling
spi_bitbang_stop() to decrement the reference and spi_master_put() as
counterpart of spi_alloc_master() to prevent a memory leak.

So now we have below patten for drivers using bitbang library:

probe:
spi_alloc_master -> Init reference count to 1
spi_bitbang_start -> Increment reference count
remove:
spi_bitbang_stop -> Decrement reference count
spi_master_put -> Decrement reference count (reference count reaches 0)

Fixup all users accordingly.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: several minor improvements and fixes

- improve dependencies using COMPILE_TEST
- fix a typo
- drop platform_set_drvdata(pdev, NULL) in error path of probe
- make MODULE_LICENSE match the header

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fsl-dspi: add missing __iomem annotation

Added missing __iomem annotation in order to fix the following
sparse warnings:

drivers/spi/spi-fsl-dspi.c:140:16: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:140:16: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:140:16: got void *
drivers/spi/spi-fsl-dspi.c:143:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:143:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:143:9: got void *
drivers/spi/spi-fsl-dspi.c:132:18: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:132:18: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:132:18: got void *
drivers/spi/spi-fsl-dspi.c:241:17: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:241:17: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:241:17: got void *
drivers/spi/spi-fsl-dspi.c:132:18: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:132:18: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:132:18: got void *
drivers/spi/spi-fsl-dspi.c:259:29: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:259:29: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:259:29: got void *
drivers/spi/spi-fsl-dspi.c:266:29: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:266:29: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:266:29: got void *
drivers/spi/spi-fsl-dspi.c:298:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:298:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:298:9: got void *
drivers/spi/spi-fsl-dspi.c:299:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:299:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:299:9: got void *
drivers/spi/spi-fsl-dspi.c:300:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:300:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:300:9: got void *
drivers/spi/spi-fsl-dspi.c:303:17: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:303:17: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:303:17: got void *
drivers/spi/spi-fsl-dspi.c:318:21: warning: incorrect type in argument 1 (different address spaces)
drivers/spi/spi-fsl-dspi.c:318:21: expected void const volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:318:21: got void *
drivers/spi/spi-fsl-dspi.c:327:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:327:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:327:9: got void *
drivers/spi/spi-fsl-dspi.c:386:9: warning: incorrect type in argument 2 (different address spaces)
drivers/spi/spi-fsl-dspi.c:386:9: expected void volatile [noderef] <asn:2>*addr
drivers/spi/spi-fsl-dspi.c:386:9: got void *
drivers/spi/spi-fsl-dspi.c:485:20: warning: incorrect type in assignment (different address spaces)
drivers/spi/spi-fsl-dspi.c:485:20: expected void *base
drivers/spi/spi-fsl-dspi.c:485:20: got void [noderef] <asn:2>*

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi: fix return value check in dspi_probe()

In case of error, the function devm_ioremap_resource() returns
ERR_PTR() and never returns NULL. The NULL test in the return
value check should be replaced with IS_ERR().

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>

spi:Add Freescale DSPI driver for Vybrid VF610 platform

The serial peripheral interface (SPI) module implemented on Freescale Vybrid
platform provides a synchronous serial bus for communication between Vybrid
and the external peripheral device.
The SPI supports full-duplex, three-wire synchronous transfer, has TX/RX FIFO
with depth of four entries.

This driver is the SPI master mode driver and has been tested on Vybrid
VF610TWR board.

Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Chao Fu <b44548@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>