dmaengine: at_xdmac: 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 ignored (apart
from emitting a warning) 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. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

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/20230919133207.1400430-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: fix potential Oops in at_xdmac_prep_interleaved()

There are two place if the at_xdmac_interleaved_queue_desc() fails which
could lead to a NULL dereference where "first" is NULL and we call
list_add_tail(&first->desc_node, ...). In the first caller, the return
is not checked so add a check for that. In the next caller, the return
is checked but if it fails on the first iteration through the loop then
it will lead to a NULL pointer dereference.

Fixes: 4e5385784e69 ("dmaengine: at_xdmac: handle numf > 1")
Fixes: 62b5cb757f1d ("dmaengine: at_xdmac: fix memory leak in interleaved mode")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/21282b66-9860-410a-83df-39c17fcf2f1b@kili.mountain
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: align declaration of ret with the rest of variables

Align the declaration of ret in atmel_xdmac_resume() with the rest of
variables. Do this by adding ret to the line with declaration for i
variable.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-8-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: add a warning message regarding for unpaused channels

Add a warning message on suspend to let the user that there are channels
not paused by their consumers.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-7-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: do not enable all cyclic channels

Do not global enable all the cyclic channels in at_xdmac_resume(). Instead
save the global status in at_xdmac_suspend() and re-enable the cyclic
channel only if it was active before suspend.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-6-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: restore the content of grws register

In case the system suspends to a deep sleep state where power to DMA
controller is cut-off we need to restore the content of GRWS register.
This is a write only register and writing bit X tells the controller
to suspend read and write requests for channel X. Thus set GRWS before
restoring the content of GE (Global Enable) regiter.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-5-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: do not resume channels paused by consumers

In case there are DMA channels not paused by consumers in suspend
process (valid on AT91 SoCs for serial driver when no_console_suspend) the
driver pauses them (using at_xdmac_device_pause() which is also the same
function called by dmaengine_pause()) and then in the resume process the
driver resumes them calling at_xdmac_device_resume() which is the same
function called by dmaengine_resume()). This is good for DMA channels
not paused by consumers but for drivers that calls
dmaengine_pause()/dmaegine_resume() on suspend/resume path this may lead to
DMA channel being enabled before the IP is enabled. For IPs that needs
strict ordering with regards to DMA channel enablement this will lead to
wrong behavior. To fix this add a new set of functions
at_xdmac_device_pause_internal()/at_xdmac_device_resume_internal() to be
called only on suspend/resume.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-4-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: fix imbalanced runtime PM reference counter

In case there are channels not paused during suspend (which on AT91 case
is valid for serial driver when no_console_suspend boot argument is used)
the at_xdmac_runtime_suspend_descriptors() was called more than
one time due to at_xdmac_off(). To fix this add a new argument to
at_xdmac_off() to specify if runtime PM reference counter needs to be
decremented for queued active descriptors. Along with it moved the
at_xdmac_runtime_suspend_descriptors() call under at_xdmac_chan_is_paused()
check on suspend path as for the rest of channels the suspend is delayed
by atmel_xdmac_prepare() in case channel is enabled. Same approach has
been applied on resume path.

Fixes: 650b0e990cbd ("dmaengine: at_xdmac: add runtime pm support")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-3-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: disable/enable clock directly on suspend/resume

Runtime PM APIs for at_xdmac just plays with clk_enable()/clk_disable()
letting aside the clk_prepare()/clk_unprepare() that needs to be
executed as the clock is also prepared on probe. Thus instead of using
runtime PM force suspend/resume APIs use
clk_disable_unprepare() + pm_runtime_put_noidle() on suspend and
clk_prepare_enable() + pm_runtime_get_noresume() on resume. This
approach as been chosen instead of using runtime PM force suspend/resume
with clk_unprepare()/clk_prepare() as it looks simpler and the final
code is better.

While at it added the missing pm_runtime_mark_last_busy() on suspend before
decrementing the reference counter.

Fixes: 650b0e990cbd ("dmaengine: at_xdmac: add runtime pm support")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-2-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: remove empty line

Remove empty line.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221117131547.293044-4-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: add runtime pm support

Add runtime PM support which involves disabling/enabling controller's
clocks on runtime PM suspend/resume ops. The runtime suspend/resume is
done based on the work submitted to the controller: runtime resume is
happening on at_xdmac_start_xfer() and runtime suspend on
at_xdmac_tasklet().

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221117131547.293044-2-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: align properly function members

Align properly function members.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221117131547.293044-3-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Replace two if statements with only one with two conditions

Add a cosmetic change and replace two if statements with a single if
statement with two conditions. In case the optional txstate parameter is
NULL, we return the dma_cookie_status, which is fine, no functional change
required.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20220802140630.243550-1-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix typo in comment

Delete the redundant word 'the'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220618130349.11507-1-wangxiang@cdjrlc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdma: handle errors of at_xdmac_alloc_desc() correctly

It seems that it is valid to have less than the requested number of
descriptors. But what is not valid and leads to subsequent errors is to
have zero descriptors. In that case, abort the probing.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220526135111.1470926-1-michael@walle.cc
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: In at_xdmac_prep_dma_memset, treat value as a single byte

The value passed in to .prep_dma_memset is to be treated as a single
byte repeating pattern.

Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20220301182551.883474-4-benjamin.walker@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dma: at_xdmac: fix a missing check on list iterator

The bug is here:
__func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue);

The list iterator 'desc' will point to a bogus position containing
HEAD if the list is empty or no element is found. To avoid dev_dbg()
prints a invalid address, use a new variable 'iter' as the list
iterator, while use the origin variable 'desc' as a dedicated
pointer to point to the found element.

Cc: stable@vger.kernel.org
Fixes: 82e2424635f4c ("dmaengine: xdmac: fix print warning on dma_addr_t variable")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220327061154.4867-1-xiam0nd.tong@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix missing unlock in at_xdmac_tasklet()

Add the missing unlock before return from at_xdmac_tasklet().

Fixes: e77e561925df ("dmaengine: at_xdmac: Fix race over irq_status")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20220107024047.1051915-1-yangyingliang@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix race over irq_status

Tasklets run with interrupts enabled, so we need to protect
atchan->irq_status with spin_lock_irq() otherwise the tasklet can be
interrupted by the IRQ that modifies irq_status. Move the dev_dbg that
prints the irq_status in at_xdmac_handle_cyclic() and lower in
at_xdmac_tasklet() where the IRQ is disabled.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-13-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_tasklet()

Apart of making the code easier to read, this patch is a prerequisite for
a functional change: tasklets run with interrupts enabled, so we need to
protect atchan->irq_status with spin_lock_irq() otherwise the tasklet can
be interrupted by the IRQ that modifies irq_status. atchan->irq_status
will be protected in a further patch.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-12-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix at_xdmac_lld struct definition

The hardware channel next descriptor view structure contains just
fields of 32 bits, while dma_addr_t can be of type u64 or u32
depending on CONFIG_ARCH_DMA_ADDR_T_64BIT. Force u32 to comply with
what the hardware expects.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-11-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix lld view setting

AT_XDMAC_CNDC_NDVIEW_NDV3 was set even for AT_XDMAC_MBR_UBC_NDV2,
because of the wrong bit handling. Fix it.

Fixes: ee0fe35c8dcd ("dmaengine: xdmac: Handle descriptor's view 3 registers")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-10-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_advance_work()

It's easier to read code with fewer levels of indentation, remove a level
of indentation in at_xdmac_advance_work()

if (!foo() & !bar()) {
}

was replaced by:

if (foo() || bar())
return;

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-9-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix concurrency over xfers_list

Since tx_submit can be called from a hard IRQ, xfers_list must be
protected with a lock to avoid concurency on the list's elements.
Since at_xdmac_handle_cyclic() is called from a tasklet, spin_lock_irq
is enough to protect from a hard IRQ.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-8-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Move the free desc to the tail of the desc list

Move the free desc to the tail of the list, so that the sequence of
descriptors is more track-able in case of debug. One would know which
descriptor should come next and could easier catch concurrency over
descriptors for example. virt-dma uses list_splice_tail_init() as well,
follow the core driver.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-7-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix race for the tx desc callback

The transfer descriptors were wrongly moved to the free descriptors list
before calling the tx desc callback. As the DMA engine drivers drop any
locks before calling the callback function, txd could be taken again,
resulting in its callback called prematurely. Fix the race for the tx desc
callback by moving the xfer desc into the free desc list after the
callback is invoked.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-6-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix concurrency over chan's completed_cookie

Caller of dma_cookie_complete is expected to hold a lock to prevent
concurrency over the channel's completed cookie marker. Call
dma_cookie_complete() with the lock held.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-5-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Print debug message after realeasing the lock

It is desirable to do the prints without the lock held if possible, so
move the print after the lock is released.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-4-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Start transfer for cyclic channels in issue_pending

Cyclic channels must too call issue_pending in order to start a transfer.
Start the transfer in issue_pending regardless of the type of channel.
This wrongly worked before, because in the past the transfer was started
at tx_submit level when only a desc in the transfer list.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-3-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Don't start transactions at tx_submit level

tx_submit is supposed to push the current transaction descriptor to a
pending queue, waiting for issue_pending() to be called. issue_pending()
must start the transfer, not tx_submit(), thus remove
at_xdmac_start_xfer() from at_xdmac_tx_submit(). Clients of at_xdmac that
assume that tx_submit() starts the transfer must be updated and call
dma_async_issue_pending() if they miss to call it (one example is
atmel_serial).

As the at_xdmac_start_xfer() is now called only from
at_xdmac_advance_work() when !at_xdmac_chan_is_enabled(), the
at_xdmac_chan_is_enabled() check is no longer needed in
at_xdmac_start_xfer(), thus remove it.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211215110115.191749-2-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Use struct_size() in devm_kzalloc()

Make use of the struct_size() helper instead of an open-coded version, in
order to avoid any potential type mistakes or integer overflows that, in
the worst scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211208001013.GA62330@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: fix compilation warning

Fixed "unused variable 'atmel_xdmac_dev_pm_ops'" compilation warning
when CONFIG_PM is not defined.

Fixes: 8e0c7e486014 ("dmaengine: at_xdmac: use pm_ptr()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211025074002.722504-1-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: use pm_ptr()

Use pm_ptr() macro to fill at_xdmac_driver.driver.pm.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211007111230.2331837-5-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: use __maybe_unused for pm functions

Use __maybe_unused for pm functions.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211007111230.2331837-4-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: fix AT_XDMAC_CC_PERID() macro

AT_XDMAC_CC_PERID() should be used to setup bits 24..30 of XDMAC_CC
register. Using it without parenthesis around 0x7f & (i) will lead to
setting all the time zero for bits 24..30 of XDMAC_CC as the << operator
has higher precedence over bitwise &. Thus, add paranthesis around
0x7f & (i).

Fixes: 15a03850ab8f ("dmaengine: at_xdmac: fix macro typo")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211007111230.2331837-3-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: call at_xdmac_axi_config() on resume path

at_xdmac could be used on SoCs which supports backup mode (where most
of the SoC power, including power to DMA controller, is closed at suspend
time). Thus, on resume, the settings which were previously done need to be
restored. Do the same for axi configuration.

Fixes: f40566f220a1 ("dmaengine: at_xdmac: add AXI priority support and recommended settings")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211007111230.2331837-2-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: use platform_driver_register

When using SCMI clocks, the clocks are probed later than subsys initcall
level. This driver uses platform_driver_probe which is not compatible with
deferred probing and won't be probed again later if probe function fails
due to clocks not being available at that time.

This patch replaces the use of platform_driver_probe with
platform_driver_register which will allow probing the driver later again
when clocks will be available.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20210728094607.50589-1-clement.leger@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Remove unused inline function at_xdmac_csize()

commit 765c37d87669 ("dmaengine: at_xdmac: rework slave configuration part")
left behind this, so can remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20210407132543.23652-1-yuehaibing@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: add AXI priority support and recommended settings

The sama7g5 version of the XDMAC supports priority configuration and
outstanding capabilities.
Add defines for the specific registers for this configuration, together
with recommended settings.
However the settings are very different if the XDMAC is a mem2mem or a
per2mem controller.
Thus, we need to differentiate according to device tree property.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20201016093918.290137-1-eugen.hristev@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: add support for sama7g5 based at_xdmac

SAMA7G5 SoC uses a slightly different variant of the AT_XDMAC.
Added support by a new compatible and a layout struct that copes
to the specific version considering the compatible string.
Only the differences in register map are present in the layout struct.
I reworked the register access for this part that has the differences.
Also the Source/Destination Interface bits are no longer valid for this
variant of the XDMAC. Thus, the layout also has a bool for specifying
whether these bits are required or not.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/20201016093850.290053-1-eugen.hristev@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: adapt perid for mem2mem operations

The PERID in the CC register for mem2mem operations must match an unused
PERID.
The PERID field is 7 bits, but the selected value is 0x3f.
On later products we can have more reserved PERIDs for actual peripherals,
thus this needs to be increased to maximum size.
Changing the value to 0x7f, which is the maximum for 7 bits field.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201016093725.289880-1-eugen.hristev@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: convert tasklets to use new tasklet_setup() API

In preparation for unconditionally passing the
struct tasklet_struct pointer to all tasklet
callbacks, switch to using the new tasklet_setup()
and from_tasklet() to pass the tasklet pointer explicitly.

Signed-off-by: Romain Perier <romain.perier@gmail.com>
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Link: https://lore.kernel.org/r/20200831103542.305571-4-allen.lkml@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Replace zero-length array with flexible-array

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Ludovic Desroches<ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200507190046.GA15298@embeddedor
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix locking in tasklet

Tasklets run with all the interrupts enabled. This means that we should
replace all the (already present) spin_lock_irqsave() uses in the tasklet
with spin_lock_irq() to protect being interrupted by a IRQ which tries
to get the same lock (via calls to device_prep_dma_* for example).

spin_lock and spin_lock_bh in tasklets are not enough to protect from IRQs,
update these to spin_lock_irq().

at_xdmac_advance_work() can be called with all the interrupts enabled (when
called from tasklet), or with interrupts disabled (when called from
at_xdmac_issue_pending). Move the locking in the callers to be able to use
spin_lock_irq() and spin_lock_irqsave() for these cases.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-10-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: GFP_KERNEL for user that can sleep

device_alloc_chan_resources can sleep, use GFP_KERNEL flag.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-9-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Drop locking in at_xdmac_alloc_chan_resources()

There is no need for locking in device_alloc_chan_resources(),
the DMA core takes care of it by using a dma_list_mutex around
the DMA devices.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-8-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Drop always true check

The code in cause is already in the else case of
'if (at_xdmac_chan_is_cyclic(atchan))', drop the redundant check.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-7-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Use devm_platform_ioremap_resource() in at_xdmac_probe()

Simplify this function implementation by using a known wrapper function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/377247f3-b53a-a9d9-66c7-4b8515de3809@web.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: check for non-empty xfers_list before invoking callback

tx descriptor retrieved from an empty xfers_list may not have valid
pointers to the callback functions.
Avoid calling dmaengine_desc_get_callback_invoke if xfers_list is empty.

Signed-off-by: Raag Jadav <raagjadav@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

dmaengine: at_xdmac: remove a stray bottom half unlock

We switched this code from spin_lock_bh() to vanilla spin_lock() but
there was one stray spin_unlock_bh() that was overlooked. This
patch converts it to spin_unlock() as well.

Fixes: d8570d018f69 ("dmaengine: at_xdmac: move spin_lock_bh to spin_lock in tasklet")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: only monitor overflow errors for peripheral xfer

The overflow error flag (ROI: Request Overflow Error) is only relevant
for the case when the channel handles a peripheral synchronized transfer.
Not in the case of memory to memory transfer where there is no hardware
request signal.

Remove the use of this interrupt source in such a case. It's based on
the first descriptor which holds the configuration for the whole
linked list transfer.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: enhance channel errors handling in tasklet

Complement the identification of errors with stopping the channel and
dumping the descriptor that led to the error case.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: remove BUG_ON macro in tasklet

Even if this case shouldn't happen when controller is properly programmed,
it's still better to avoid dumping a kernel Oops for this.
As the sequence may happen only for debugging purposes, log the error and
just finish the tasklet call.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: Fix wrongfull report of a channel as in use

atchan->status variable is used to store two different information:
- pass channel interrupts status from interrupt handler to tasklet;
- channel information like whether it is cyclic or paused;

This causes a bug when device_terminate_all() is called,
(AT_XDMAC_CHAN_IS_CYCLIC cleared on atchan->status) and then a late End
of Block interrupt arrives (AT_XDMAC_CIS_BIS), which sets bit 0 of
atchan->status. Bit 0 is also used for AT_XDMAC_CHAN_IS_CYCLIC, so when
a new descriptor for a cyclic transfer is created, the driver reports
the channel as in use:

if (test_and_set_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status)) {
dev_err(chan2dev(chan), "channel currently used\n");
return NULL;
}

This patch fixes the bug by adding a different struct member to keep
the interrupts status separated from the channel status bits.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: move spin_lock_bh to spin_lock in tasklet

as you are already in a tasklet, it is unnecessary to call spin_lock_bh.

Signed-off-by: Barry Song <21cnbao@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: simplify getting .drvdata

We should get drvdata from struct device directly. Going via
platform_device is an unneeded step back and forth.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: at_xdmac: fix rare residue corruption

Despite the efforts made to correctly read the NDA and CUBC registers,
the order in which the registers are read could sometimes lead to an
inconsistent state.

Re-using the timeline from the comments, this following timing of
registers reads could lead to reading NDA with value "@desc2" and
CUBC with value "MAX desc1":

INITD -------- ------------
|____________________|
_______________________ _______________
NDA @desc2 \/ @desc3
_______________________/\_______________
__________ ___________ _______________
CUBC 0 \/ MAX desc1 \/ MAX desc2
__________/\___________/\_______________
| | | |
Events:(1)(2) (3)(4)

(1) check_nda = @desc2
(2) initd = 1
(3) cur_ubc = MAX desc1
(4) cur_nda = @desc2

This is allowed by the condition ((check_nda == cur_nda) && initd),
despite cur_ubc and cur_nda being in the precise state we don't want.

This error leads to incorrect residue computation.

Fix it by inversing the order in which CUBC and INITD are read. This
makes sure that NDA and CUBC are always read together either _before_
INITD goes to 0 or _after_ it is back at 1.
The case where NDA is read before INITD is at 0 and CUBC is read after
INITD is back at 1 will be rejected by check_nda and cur_nda being
different.

Fixes: 53398f488821 ("dmaengine: at_xdmac: fix residue corruption")
Cc: stable@vger.kernel.org
Signed-off-by: Maxime Jayat <maxime.jayat@mobile-devices.fr>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Handle return value of clk_prepare_enable.

clk_prepare_enable() can fail here and we must check its return value.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Fix compilation warning.

Replace '%d' by '%zu' to fix the compilation warning:-
"format ‘%d’ expects argument of type ‘int’,but argument has type ‘size_t’ [-Wformat=]"

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: don't restore unsaved status

save_gs is supposed to save the channel status in order to be restored at
resume time but it is never updated and is always 0. Anyway, the channel
status is updated in the per channel loop later in the resume function.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Use dma_pool_zalloc

We should use dma_pool_zalloc instead of dma_pool_alloc/memset.

Signed-off-by: Souptick joarder <jrdr.linux@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix to pass correct device identity to free_irq()

free_irq() expects the same device identity that was passed to
corresponding request_irq(), otherwise the IRQ is not freed.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: convert callback to helper function

This is in preperation of moving to a callback that provides results to the
callback for the transaction. The conversion will maintain current behavior
and the driver must convert to new callback mechanism at a later time in
order to receive results.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix debug string

mbr_ds is an integer, don't use %pad to print it.

Fixes: commit 268914f4e7a0 ("dmaengine: at_xdmac: use %pad format string for dma_addr_t")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix un-exported functions

The at_xdmac_init_used_desc() and at_xdmac_prep_dma_memset()
functions are not exported outside the driver, so make them
static to avoid the following warnings:

drivers/dma/at_xdmac.c:459:6: warning: symbol 'at_xdmac_init_used_desc' was not declared. Should it be static?
drivers/dma/at_xdmac.c:1205:32: warning: symbol 'at_xdmac_prep_dma_memset' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: double FIFO flush needed to compute residue

Due to the way CUBC register is updated, a double flush is needed to
compute an accurate residue. First flush aim is to get data from the DMA
FIFO and second one ensures that we won't report data which are not in
memory.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #v4.1 and later
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix residue corruption

An unexpected value of CUBC can lead to a corrupted residue. A more
complex sequence is needed to detect an inaccurate value for NCA or CUBC.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #v4.1 and later
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: align descriptors on 64 bits

Having descriptors aligned on 64 bits allows update CNDA and CUBC in an
atomic way.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #v4.1 and later
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix residue computation

When computing the residue we need two pieces of information: the current
descriptor and the remaining data of the current descriptor. To get
that information, we need to read consecutively two registers but we
can't do it in an atomic way. For that reason, we have to check manually
that current descriptor has not changed.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Suggested-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reported-by: David Engraf <david.engraf@sysgo.com>
Tested-by: David Engraf <david.engraf@sysgo.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #4.1 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix resume for cyclic transfers

When having cyclic transfers, the channel was paused when performing
suspend but was not correctly resumed.

Signed-off-by: Songjun Wu <songjun.wu@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Cc: <stable@vger.kernel.org> # 4.1 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix at_xdmac_prep_dma_memcpy()

This patch fixes at_xdmac_prep_dma_memcpy(). Indeed the data width field
of the Channel Configuration register was not updated properly in the
loop: the bits of the dwidth field were not cleared before adding their
new value.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee70 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Cc: stable@vger.kernel.org #4.1 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Remove unnecessary synchronize_irq() before free_irq()

Calling synchronize_irq() right before free_irq() is quite useless. On one
hand the IRQ can easily fire again before free_irq() is entered, on the
other hand free_irq() itself calls synchronize_irq() internally (in a race
condition free way), before any state associated with the IRQ is freed.

Patch was generated using the following semantic patch:
// <smpl>
@@
expression irq;
@@
-synchronize_irq(irq);
free_irq(irq, ...);
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix bad behavior in interleaved mode

When performing interleaved transfers with numf > 1, an extra line is
copied. The mbr.bc field is incremented once too often. The length of
the block is (BLEN+1) microblocks.

Signed-off-by: Sylvain ETIENNE <Sylvain.ETIENNE@ingenico.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: 4e5385784e69 ("dmaengine: at_xdmac: handle numf > 1")
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix false condition for memset_sg transfers

The code was not in agreement with the comments.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org # 4.3 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix macro typo

Fix typo in a macro which was not used until now. It explains why there
is no error at compilation time.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: e1f7c9eee707 "dmaengine: at_xdmac: creation of the atmel eXtended
DMA Controller driver"
Cc: stable@vger.kernel.org # 3.19 and later
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers

When setting the channel configuration register, the perid field is not
set to 0 since it is useless for mem2mem transfers. Unfortunately, a
device has 0 as perid. It could cause spurious flags status because
the controller could mix some events from the two channels.
For that reason, use the highest perid value for mem2mem transfers since it
doesn't match the perid of other devices.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: use %pad format string for dma_addr_t

dma_addr_t may be defined as 32 or 64 bit depending on configuration,
so it cannot be printed using the normal format strings, as
gcc correctly warns:

drivers/dma/at_xdmac.c: In function 'at_xdmac_interleaved_queue_desc':
drivers/dma/at_xdmac.c:922:51: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t {aka long long unsigned int}' [-Wformat=]

This changes the format strings to use the special "%pad" format
string that prints a dma_addr_t, and changes the arguments so we
pass the address by reference as required.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix memory leak in interleaved mode

In interleaved mode, when numf > 1, we have only one descriptor for the
transfer but this descriptor has to be added to the descs_list. If not,
when doing remove_xfer, the descriptor won't be put back in the
free_descs_list.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: handle numf > 1

Handle 'numf > 1' case for interleaved mode.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: clean used descriptor

When putting back a descriptor to the free descs list, some fields are
not set to 0, it can cause bugs if someone uses it without having this
in mind.
Descriptor are not put back one by one so it is easier to clean
descriptors when we request them.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org #4.2
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: change block increment addressing mode

The addressing mode we were using was not only incrementing the address at
each microblock, but also at each data boundary, which was severely slowing
the transfer, without any benefit since we were not using the data stride.

Switch to the micro block increment only in order to get back to an
acceptable performance level.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: 6007ccb57744 ("dmaengine: xdmac: Add interleaved transfer support")
Cc: stable@vger.kernel.org #4.2
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix bug in prep_dma_cyclic

In cyclic mode, the round chaining has been broken by the introduction
of at_xdmac_queue_desc(): AT_XDMAC_MBR_UBC_NDE is set for all descriptors
excepted for the last one. at_xdmac_queue_desc() has to be called one
more time to chain the last and the first descriptors.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: 0d0ee751f7f7 ("dmaengine: xdmac: Rework the chaining logic")
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Add scatter gathered memset support

The XDMAC also supports memset operations over discontiguous areas. Add the
necessary logic to support this.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix transfer data width in at_xdmac_prep_slave_sg()

This patch adds the missing update of the transfer data width in
at_xdmac_prep_slave_sg().

Indeed, for each item in the scatter-gather list, we check whether the
transfer length is aligned with the data width provided by
dmaengine_slave_config(). If so, we directly use this data width for the
current part of the transfer we are preparing. Otherwise, the data width
is reduced to 8 bits (1 byte). Of course, the actual number of register
accesses must also be updated to match the new data width.

So one chunk was missing in the original patch (see Fixes tag below): the
number of register accesses was correctly set to (len >> fixed_dwidth) in
mbr_ubc but the real data width was not updated in mbr_cfg. Since mbr_cfg
may change for each part of the scatter-gather transfer this also explains
why the original patch used the Descriptor View 2 instead of the
Descriptor View 1.

Let's take the example of a DMA transfer to write 8bit data into an Atmel
USART with FIFOs. When FIFOs are enabled in the USART, its Transmit
Holding Register (THR) works in multidata mode, that is to say that up to
4 8bit data can be written into the THR in a single 32bit access and it is
still possible to write only one data with a 8bit access. To take
advantage of this new feature, the DMA driver was modified to allow
multiple dwidths when doing slave transfers.
For instance, when the total length is 22 bytes, the USART driver splits
the transfer into 2 parts:

First part: 20 bytes transferred through 5 32bit writes into THR
Second part: 2 bytes transferred though 2 8bit writes into THR

For the second part, the data width was first set to 4_BYTES by the USART
driver thanks to dmaengine_slave_config() then at_xdmac_prep_slave_sg()
reduces this data width to 1_BYTE because the 2 byte length is not aligned
with the original 4_BYTES data width. Since the data width is modified,
the actual number of writes into THR must be set accordingly.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Fixes: 6d3a7d9e3ada ("dmaengine: at_xdmac: allow muliple dwidths when doing slave transfers")
Cc: stable@vger.kernel.org #4.0 and later
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix bug about channel configuration

When using descriptor view 2 or higher, we don't write the configuration
into AT_XDMAC_CC register because this configuration will be fetch from
the descriptor. Unfortunately, the PROT bit is not updated with this
method, we have to do it manually before enabling the channel.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix indentation

Fix indentation.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Add memset support

The XDMAC supports memset transfers, both over contiguous areas, and over
discontiguous areas through a LLI.

The current memset operation only supports contiguous memset for now, add some
support for it. Scatter-gathered memset will come eventually.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: Move icg helpers to global header

Now that we can have ICGs set for both the source and destination (using
the icg field of struct data_chunk) or for only the source or the
destination (using the dst_icg or src_icg respectively), and that these
fields can be ignored depending on other parameters (src_inc, src_sgl,
etc.), the logic to get the actual ICG value can be quite tricky.

The XDMAC driver was already implementing it, but since we will need it in
other drivers, we can move it to the main header file.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: rework slave configuration part

Rework slave configuration part in order to more report wrong errors
about the configuration.
Only maxburst and addr width values are checked when doing the slave
configuration. The validity of the channel configuration is done at
prepare time.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org # 4.0 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: lock fixes

Using _bh variant for spin locks causes this kind of warning:
Starting logging: ------------[ cut here ]------------
WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151
__local_bh_enable_ip+0xe8/0xf4()
Modules linked in:
CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94
Hardware name: Atmel SAMA5
[<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14)
[<c00118a4>] (show_stack) from [<c001bbcc>]
(warn_slowpath_common+0x80/0xac)
[<c001bbcc>] (warn_slowpath_common) from [<c001bc14>]
(warn_slowpath_null+0x1c/0x24)
[<c001bc14>] (warn_slowpath_null) from [<c001e28c>]
(__local_bh_enable_ip+0xe8/0xf4)
[<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>]
(at_xdmac_device_terminate_all+0xf4/0x100)
[<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>]
(atmel_complete_tx_dma+0x34/0xf4)
[<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>]
(at_xdmac_tasklet+0x14c/0x1ac)
[<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>]
(tasklet_action+0x68/0xb4)
[<c001de58>] (tasklet_action) from [<c001dfdc>]
(__do_softirq+0xfc/0x238)
[<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34)
[<c001e140>] (run_ksoftirqd) from [<c0033a3c>]
(smpboot_thread_fn+0x138/0x18c)
[<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0)
[<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34)
---[ end trace b57b14a99c1d8812 ]---

It comes from the fact that devices can called some code from the DMA
controller with irq disabled. _bh variant is not intended to be used in
this case since it can enable irqs. Switch to irqsave/irqrestore variant to
avoid this situation.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org # 4.0 and later
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Add interleaved transfer support

The XDMAC supports interleaved tranfers through its flexible descriptor
configuration.

Add support for that kind of transfers to the dmaengine driver.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Rework the chaining logic

So far, we were setting the NDE bit in our descriptors through some logic to
try to see if we were the last descriptor in the chain.

However, that was turning out to be rather complex to get right, while this
information is also available when we actually chain a new descriptor after an
already existing one.

Simplify this by never setting NDE unless when we actually chain a descriptor.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Add function to align width

The code has some logic to compute the burst width according to the alignment
of the address we're using.

Move that in a function of its own to reduce code duplication.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: Handle descriptor's view 3 registers

The XDMAC DMA controller uses a concept of views to be able to handle
descriptors of different sizes.

So far, only the views 1 and 2 were handled by the driver. Unfortunately, we
need some of the configuration fields found in the view 3 in order to support
memset and interleaved transfers.

Add the definition for the view 3 registers, and the needed code to handle view
3 descriptors.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: unlock spin lock before return

Signed-off-by: Niklas Cassel <niklass@axis.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix for chan conf simplification

When simplificating the channel configuration, the cyclic case has been
forgotten. It leads to use bad configuration causing many bugs.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: allow muliple dwidths when doing slave transfers

When using FIFO, we need to support differents data width in a single
transfer. For example, serial device which usually uses 1-byte data
width will use 4-bytes data width when using the FIFO. If the transfer
size is not aligned on 4-bytes then the end of the transfer will be
performed with 1-byte data-width. For that reason,
at_xdmac_prep_slave_sg() now builds linked list descriptors using view 2
instead of view 1 so each of them can update the DWIDTH field into the
Channel Configuration Register.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: simplify channel configuration stuff

This patch simplifies the channel configuration register management.
Relying on a "software snapshot" of the configuration is not safe and
too complex.

Multiple dwidths will be introduced for slave transfers. In this case,
it becomes quite difficult to have an accurate snapshot of the channel
configuration register in the way it is done. Using the channel
configuration available in the lli descriptor simplifies this stuff.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: introduce save_cc field

When suspending the device, read the channel configuration directly from
the register instead of relying on a software snapshot, it will be
safer.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: wait for in-progress transaction to complete after pausing a channel

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: drop owner assignment from platform_drivers

This platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Declare slave capabilities for the generic code

Now that the generic slave caps code can make use of the device assigned
capabilities, instead of relying on a callback to be implemented.

Make use of this code.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: split device_control

Use newly introduced callbacks.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: Make the destination abbreviation coherent

The dmaengine header abbreviates destination as at least two different strings.
Make a coherent use of a single one.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: Add DMA_PRIVATE

same issue as commit 7f5ae3553685:
"Without DMA_PRIVATE the driver is not able to allocate more than one channel.
Since it uses dma_get_any_slave_channel that calls private_candidate, the
second allocation fails at
/* some channels are already publicly allocated */
"

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix missing spin_unlock

Lock taken when entering the function but unlock missing before it
returns.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix a bug in transfer residue computation

The total size of the transfer was wrong in at_xdmac_prep_slave_sg()
resulting in bad computation of the transfer residue by
at_xdmac_tx_status().

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix software lockup at_xdmac_tx_status()

According to the Atmel eXtended DMA controller datasheet, requesting a
DMA transfer flush for a channel is only revelant when this transfer is
source peripheral synchronized.

So we have to check this condition before requesting a channel flush by
writing the channel bit into the Global channel SoftWare Flush (GSWF)
register then waiting for flush to complete by monitoring the end of
Flush Interrupt Status (FIS) bit in the Channel Interrupt Status (CIS)
register.

Indeed, for non source peripheral synchronized transfer, writing the
channel bit into the GSWF register does nothing. Especially, the FIS bit
is never set into the CIS register. The former code looped forever
waiting for this bit to be set.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: remove chancnt affectation

Remove chancnt affectation since it is done in dma_async_device_regiser.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: prefer usage of readl/writel_relaxed

_relaxed version of readl and writel are not implemented on all
architecture so COMPILE_TEST has to be removed in order to not cause
some build failures.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: fix print warning on dma_addr_t variable

As documented in printk-formats.txt the dma_addr_t should be printed with
%pad specfiers. This way it works on all archs.

make.cross ARCH=s390

All warnings:

drivers/dma/at_xdmac.c: In function 'at_xdmac_prep_slave_sg':
>> drivers/dma/at_xdmac.c:621:3: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
>> drivers/dma/at_xdmac.c:621:3: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
>> drivers/dma/at_xdmac.c:628:4: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
drivers/dma/at_xdmac.c: In function 'at_xdmac_prep_dma_cyclic':
>> drivers/dma/at_xdmac.c:663:2: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan), "%s: buf_addr=0x%08x, buf_len=%d, period_len=%d, dir=%s, flags=0x%lx\n",
^
>> drivers/dma/at_xdmac.c:690:3: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
>> drivers/dma/at_xdmac.c:709:3: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
>> drivers/dma/at_xdmac.c:709:3: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
>> drivers/dma/at_xdmac.c:716:4: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),

>> drivers/dma/at_xdmac.c:731:2: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
drivers/dma/at_xdmac.c: In function 'at_xdmac_prep_dma_memcpy':
>> drivers/dma/at_xdmac.c:765:2: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan), "%s: src=0x%08x, dest=0x%08x, len=%d, flags=0x%lx\n",
^
>> drivers/dma/at_xdmac.c:765:2: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan), "%s: remaining_size=%u\n", __func__, remaining_size);
^
>> drivers/dma/at_xdmac.c:845:3: warning: format '%x' expects argument of type 'unsigned int', but argument 5 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
>> drivers/dma/at_xdmac.c:845:3: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
>> drivers/dma/at_xdmac.c:852:4: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),
^
drivers/dma/at_xdmac.c: In function 'at_xdmac_tx_status':
>> drivers/dma/at_xdmac.c:929:2: warning: format '%x' expects argument of type 'unsigned int', but argument 6 has type 'dma_addr_t' [-Wformat=]
dev_dbg(chan2dev(chan),

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: xdmac: fix print warning on size_t variable

As documented in printk-formats.txt the size_t should be printed with
%zu/%zd specfiers. This way it works on all archs.

make.cross ARCH=avr32

All warnings:

drivers/dma/at_xdmac.c: In function 'at_xdmac_prep_dma_cyclic':
>> drivers/dma/at_xdmac.c:663: warning: format '%d' expects type 'int', but argument 6 has type 'size_t'
>> drivers/dma/at_xdmac.c:663: warning: format '%d' expects type 'int', but argument 7 has type 'size_t'
drivers/dma/at_xdmac.c: In function 'at_xdmac_prep_dma_memcpy':
>> drivers/dma/at_xdmac.c:765: warning: format '%d' expects type 'int', but argument 7 has type 'size_t'
>> drivers/dma/at_xdmac.c:794: warning: format '%u' expects type 'unsigned int', but argument 5 has type 'size_t'
>> drivers/dma/at_xdmac.c:815: warning: format '%u' expects type 'unsigned int', but argument 5 has type 'size_t'

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix usage of read, write wrappers

This driver uses read_relaxed and writel_relaxed to read, write to IO
memory. the config defines COMPILE_TEST so gets compiled on different archs.
This causes issue as few archs like x86 etc don't define it.
So use readl/writel which is defined in all archs

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: fix semicolon.cocci warnings

drivers/dma/at_xdmac.c:702:3-4: Unneeded semicolon

Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver

New atmel DMA controller known as XDMAC, introduced with SAMA5D4
devices.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>