mtd: st_spi_fsm: 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() will be 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>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/linux-mtd/20231008200143.196369-9-u.kleine-koenig@pengutronix.de

mtd: st_spi_fsm: Convert to devm_platform_ioremap_resource()

Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230707040622.78174-16-frank.li@vivo.com

mtd: st_spi_fsm: Use the devm_clk_get_enabled() helper function

Use the devm_clk_get_enabled() helper function instead of hand-writing it.
It saves some line of codes.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/4025ec3980a956b0e776024e88ec960afc457501.1681636580.git.christophe.jaillet@wanadoo.fr

mtd: st_spi_fsm: Simplify error checking in .probe() a bit

Instead of ending each if branch with the same check, do it once
unconditionally after the if block.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220607152458.232847-5-u.kleine-koenig@pengutronix.de

mtd: st_spi_fsm: Disable clock only after device was unregistered

Until mtd_device_unregister() returns the device is expected to be
operational. So only disable the clock after the mtd is unregistered.

Fixes: 1fefc8ecb834 ("mtd: st_spi_fsm: add missing clk_disable_unprepare() in stfsm_remove()")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220607152458.232847-4-u.kleine-koenig@pengutronix.de

mtd: st_spi_fsm: Warn about failure to unregister mtd device

mtd_device_unregister() shouldn't fail. Wail loudly if it does anyhow.

This matches how other drivers (e.g. nand/raw/nandsim.c) use
mtd_device_unregister().

By returning 0 in the platform remove callback a generic error message
by the device core is suppressed, nothing else changes.

This is a preparation for making platform remove callbacks return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220607152458.232847-3-u.kleine-koenig@pengutronix.de

mtd: st_spi_fsm: Add a clk_disable_unprepare() in .probe()'s error path

For all but one error path clk_disable_unprepare() is already there. Add
it to the one location where it's missing.

Fixes: 481815a6193b ("mtd: st_spi_fsm: Handle clk_prepare_enable/clk_disable_unprepare.")
Fixes: 69d5af8d016c ("mtd: st_spi_fsm: Obtain and use EMI clock")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220607152458.232847-2-u.kleine-koenig@pengutronix.de

mtd: st_spi_fsm: add missing clk_disable_unprepare() in stfsm_remove()

Clock source is prepared and enabled by clk_prepare_enable()
in probe function, but not disabled or unprepared in remove
function.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220516092911.953066-1-yangyingliang@huawei.com

mtd: st_spi_fsm: convert comma to semicolon

Replace a comma between expression statements by a semicolon.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210108092325.19037-1-zhengyongjun3@huawei.com

mtd: st_spi_fsm: remove unused field from struct stfsm

The 'region' field in struct stfsm is unused and can be removed.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 420

Based on 1 normalized pattern(s):

this code 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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 6 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190113.627158185@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mtd: Stop updating erase_info->state and calling mtd_erase_callback()

MTD users are no longer checking erase_info->state to determine if the
erase operation failed or succeeded. Moreover, mtd_erase_callback() is
now a NOP.

We can safely get rid of all mtd_erase_callback() calls and all
erase_info->state assignments. While at it, get rid of the
erase_info->state field, all MTD_ERASE_XXX definitions and the
mtd_erase_callback() function.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Bert Kenward <bkenward@solarflare.com>
---
Changes in v2:
- Address a few coding style issues (reported by Miquel)
- Remove comments that are no longer valid (reported by Miquel)

mtd: st_spi_fsm: use %*ph to print small buffer

Use %*ph format to print small buffer as hex string.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Antonio Cardace <anto.cardace@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

mtd: st_spi_fsm: Handle clk_prepare_enable/clk_disable_unprepare.

- clk_prepare_enable() can fail here and we must check its return value.
- stfsm_probe() can fail here and we must disable clock.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

mtd: st_spi_fsm: remove SPINOR_OP_RDSR2 and use SPINOR_OP_RDCR instead

The 35h instruction op code has two aliases/macro definitions:
- SPINOR_OP_RDCR from include/linux/mtd/spi-nor.h
- SPINOR_OP_RDSR2 from drivers/mtd/devices/serial_flash_cmds.h

Actually, some manufacturers name the associated internal register Status
Register 2 whereas other manufacturers name it Configuration Register
hence the two different macros for the very same instruction op code.

Since the spi-nor.h file is the reference file for all SPI NOR instruction
op codes, this patch removes the definition of the SPINOR_OP_RDSR2 macro.

Also the SPINOR_OP_RDSR2 macro will be associated to another instruction
op code in a further patch so we need to avoid a conflict defining this
macro twice. Indeed the JESD216 rev B specification, defining the SFDP
tables, also refers to the 3Eh and 3Fh instruction op codes to write/read
the Status Register 2 on some SPI NOR flash memories, the 35h op code
still being used to read the Configuration Register/Status Register 2 on
other memories.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@microchip.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>

mtd: spi-nor: rename SPINOR_OP_* macros of the 4-byte address op codes

This patch renames the SPINOR_OP_* macros of the 4-byte address
instruction set so the new names all share a common pattern: the 4-byte
address name is built from the 3-byte address name appending the "_4B"
suffix.

The patch also introduces new op codes to support other SPI protocols such
as SPI 1-4-4 and SPI 1-2-2.

This is a transitional patch and will help a later patch of spi-nor.c
to automate the translation from the 3-byte address op codes into their
4-byte address version.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Marek Vasut <marek.vasut@gmail.com>

mtd: drop unnecessary partition parser data

We should assign the MTD dev.of_node instead of the parser data field.
This gets us the equivalent partition parser behavior with fewer special
fields and parameter passing.

Also convert several of these to mtd_device_register(), since we don't
need the 2nd and 3rd parameters anymore.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

mtd: st_spi_fsm: Fix [-Wsign-compare] build warning

drivers/mtd/devices/st_spi_fsm.c:1647:17:
warning: comparison between signed and unsigned integer expressions

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Obtain and use EMI clock

ST's Common Clk Framework is now available. This patch ensures the FSM
makes use of it by obtaining and enabling the EMI clock. If system fails
to provide the EMI clock, we bomb out.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Extend fsm_clear_fifo to handle unwanted bytes

Under certain conditions, the SPI-FSM Controller can be left in a state where
the data FIFO is not entirely empty. This can lead to problems where subsequent
data transfers appear to have been shifted by a number of unidentified bytes.

One simple example would be an errant FSM sequence which loaded more data to the
FIFO than was read by the host. Another more interesting case results from an
obscure artefact in the FSM Controller. When switching from data transfers in
x4 or x2 mode to data transfers in x1 mode, extraneous bytes will appear in the
FIFO, unless the previous data transfer was a multiple of 32 cycles (i.e. 8
bytes for x2, and 16 bytes for x4). This applies equally whether FSM is being
operated directly by a S/W driver, or by the SPI boot-controller in FSM-Boot
mode. Furthermore, data in the FIFO not only survive a transition between
FSM-Boot and FSM, but also a S/W reset of IP block [1].

By taking certain precautions, it is possible to prevent the driver from causing
this type of problem (e.g. ensuring that the host and programmed sequence
agree on the transfer size, and restricting transfer sizes to multiples of
32-cycles [2]). However, at the point the driver is loaded, no assumptions can be
made regarding the state of the FIFO. Even if previous S/W drivers have behaved
correctly, it is impossible to control the number of transactions serviced by
the controller operating in FSM-Boot.

To address this problem, we ensure the FIFO is cleared during initialisation,
before performing any FSM operations. Previously, the fsm_clear_fifo() code was
capable of detecting and clearing any unwanted 32-bit words from the FIFO. This
patch extends the capability to handle an arbitrary number of bytes present in
the FIFO [3]. Now that the issue is better understood, we also remove the calls
to fsm_clear_fifo() following the fsm_read() and fsm_write() operations.

The process of actually clearing the FIFO deserves a mention. While the FIFO
may contain any number of bytes, the SPI_FAST_SEQ_STA register only reports the
number of complete 32-bit words present. Furthermore, data can only be drained
from the FIFO by reading complete 32-bit words. With this in mind, a two stage
process is used to the clear the FIFO:

1. Read any complete 32-bit words from the FIFO, as reported by the
SPI_FAST_SEQ_STA register.

2. Mop up any remaining bytes. At this point, it is not known if there
are 0, 1, 2, or 3 bytes in the FIFO. To handle all cases, a dummy
FSM sequence is used to load one byte at a time, until a complete
32-bit word is formed; at most, 4 bytes will need to be loaded.

[1] Although this issue has existed since early versions of the SPI-FSM
controller, its full extent only emerged recently as a consequence of the
targetpacks starting to use FSM-Boot(x4) as the default configuration.

[2] The requirement to restrict transfers to multiples of 32 cycles was found
empirically back when DUAL and QUAD mode support was added. The current
analysis now gives a satisfactory explanation for this requirement.

[3] Theoretically, it is possible for the FIFO to contain an arbitrary number of
bits. However, since there are no known use-cases that leave incomplete
bytes in the FIFO, only words and bytes are considered here.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: devices: drop owner assignment from platform_drivers

A 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>

mtd: st_spi_fsm: 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: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: correct type issues

Compile-testing for a 64-bit arch uncovers several bad casts:

In file included from include/linux/linkage.h:4:0,
from include/linux/kernel.h:6,
from drivers/mtd/devices/st_spi_fsm.c:15:
drivers/mtd/devices/st_spi_fsm.c: In function ‘stfsm_read_fifo’:
drivers/mtd/devices/st_spi_fsm.c:758:11: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
BUG_ON((((uint32_t)buf) & 0x3) || (size & 0x3));
...

Use uintptr_t instead of uint32_t, since it's guaranteed to be
pointer-sized.

We also see this warning, if size_t is not 32 bits wide:

In file included from drivers/mtd/devices/st_spi_fsm.c:15:0:
drivers/mtd/devices/st_spi_fsm.c: In function ‘stfsm_mtd_write’:
include/linux/kernel.h:712:17: warning: comparison of distinct pointer types lacks a cast [enabled by default]
(void) (&_min1 == &_min2); \
^
drivers/mtd/devices/st_spi_fsm.c:1704:11: note: in expansion of macro ‘min’
bytes = min(FLASH_PAGESIZE - page_offs, len);
^

Just use min_t() to force the type conversion, since we don't really
want to upgrade 'page_offs' and 'bytes' to size_t; they only should be
handling <= 256 byte offsets.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>

mtd: st_spi_fsm: begin using spi-nor.h opcodes

Many of the serial_flash_cmds.h opcodes are duplicated with spi-nor.h.
Let's begin to unify them.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>

mtd: st_spi_fsm: replace FLACH_CMD_* with SPINOR_OP_*

Begin to unify the differences between serial_flash_cmds.h and
spi-nor.h.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>

mtd: st_spi_fsm: kill duplicate CMD definitions

These are also in serial_flash_cmds.h. (FWIW, I didn't know the C
preprocessor allowed redefinitions without warning like this.)

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>

mtd: st_spi_fsm: Add support for Macronix MX25L3255E

This patch adds support for the Macronix MX25L3255E device. Unlike the other
Macronix devices we have seen, this device supports WRITE_1_4_4 at reasonable
frequencies. Rather than masking out WRITE_1_4_4 support altogether, we now
rely on the table parameters to indicate whether or not WRITE_1_4_4 should be
used.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add Spansion S25FL032P to device table

Add Spansion S25FL032P to the list of known devices.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Refactor status register operations

This patch refactors the fsm_read_status() and fsm_write_status() code to
support 1 or 2 byte operations, with a specified command. This allows us to
remove device/register specific code, such as the N25Q fsm_wrvcr() function.

The 'QE' configuration code is updated accordingly, with minor tweaks to ensure
the register values are only written if actually required. One notable change
in this area is that the 'W25Q_STATUS_QE' bit-field is now defined with respect
to the 'SR2' register, rather than the combined 'SR1+SR2' register which is only
used for write operations.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Update Macronix 'QE' configuration

Update the configuration of the Macronix 'QE' bit, such that
we only set or clear the bit if required.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Update Macronix 32-bit addressing support

Support for the Macronix 32-bit addressing scheme was originally developed using
the MX25L25635E device. As is often the case, it was found that the presence of
a "WAIT" instruction was required for the "EN4B/EX4B" FSM Sequence to complete.
(It is known that the SPI FSM Controller makes certain undocumented assumptions
regarding what constitutes a valid sequence.) However, further testing
suggested that a small delay was required after issuing the "EX4B" command;
without this delay, data corruptions were observed, consistent with the device
not being ready to retrieve data. Although the issue was not fully understood,
the workaround of adding a small delay was implemented, while awaiting
clarification from Macronix.

The same behaviour has now been found with a second Macronix device, the
MX25L25655E. However, with this device, it seems that the delay is also
required after the 'EN4B' commands. This discovery has prompted us to revisit
the issue.

Although still not conclusive, further tests have suggested that the issue is
down to the SPI FSM Controller, rather than the Macronix devices. Furthermore,
an alternative workaround has emerged which is to set the WAIT time to
0x00000001, rather then 0x00000000. (Note, the WAIT instruction is used purely
for the purpose of achieving "sequence validity", rather than actually
implementing a delay!)

The issue is now being investigated by the Design and Validation teams. In the
meantime, we implement the alternative workaround, which reduces the effective
delay from 1us to 1ns.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add Macronix MX25L25655E device

Add Macronix MX25L25655E to the list of known devices.

Signed-off-by: Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Succinctly reorganise .remove()

Reported-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Allow loop to run at least once before giving up CPU

Reported-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Correct vendor name spelling issue - missing "M"

Reported-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Avoid duplicating MTD core code

Reported-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Remove useless consts from function arguments

Reported-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[Brian: tweaked a bit]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Convert ST SPI FSM (NOR) Flash driver to new DT partitions

The old API expected a "partitions" property provided a phandle to a
separate partitions node, which itself contained yet more nodes each
representing one partition. The new API rids the requirement for the
superfluous intermediary partitions node. This patch provides the
added information required for automatic parsing by the core.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Move runtime configurable msg sequences into device's struct

Until now the dynamically configurable message sequences for read, write
and enable 32bit addressing have been global. Brian makes a good point
why this should not be the case. If there are ever two FSM's located on
the same platform, we could be potentially introducing a race condition
on "needlessly shared data".

Suggested-by: Brian Norris <computersforpeace@gmail.com>
Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply the W25Qxxx chip specific configuration call-back

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply the S25FLxxx chip specific configuration call-back

This patch allows us to prepare some of the message sequences which will
be required to talk to the S25FLxxx family of Serial Flash devices. It
also allows us to do some required extra operations after any busy wait
failures.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply the MX25xxx chip specific configuration call-back

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add the ability to write to FSM's status register

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add the ability to read the FSM's status

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Erase partly or as a whole a Serial Flash device

When an erase is requested by userspace the MTD framework calls back
into the driver to conduct the actual command issue. Here we provide the
routines which do exactly that. We can choose to either do an entire chip
erase or by sector.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply a busy wait for post-write status

When we write data to the Serial Flash chip we'll wait a predetermined
period of time before giving up. During that period of time we poll the
status register until completion.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Write to Flash via the FSM FIFO

When we write data to the FIFO the FSM Controller subsequently writes
that data out to the Serial Flash chip.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add the ability to read from a Serial Flash device

When a read is issued by userspace the MTD framework calls back into
the driver to conduct the actual command issue and data extraction.
Here we provide the routines which do exactly that.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Prepare default sequences for read/write/erase

Most chips require a predefined set of FSM message sequences for read,
write and erase operations. This patch provides a way to set them up,
which it will do so if a chip specific initialisation routine isn't
been provided.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply the N25Qxxx chip specific configuration call-back

In the FSM driver we handle chip differences by providing the possibility
of calling back into a chip specific initialisation routine. In this patch
we provide one for the N25Qxxx series, which endeavours to setup things
like the read, write and erase sequences, as they differ from the
default. We also configure 32bit support and the amount of dummy cycles to
use.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply the N25Qxxx specific read configurations

The N25Qxxx Serial Flash devices required different sequence
configurations depending on whether they're running in 24bit (3Byte)
or 32bit (4Byte) mode. We provide those here.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Provide the default read/write configurations

Message sequences can vary depending on how many pads (lines) are
required to address the chip (mode & dummy), how many data pads (lines)
are required to write out to the chip which will determine speed
amongst other things which are detailed by the SFDP specification. We
are able to use multiple configurations for each chip, but they need
to me matched to a device's capabilities. These configurations are
listed in preference order - most preferred first.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Update the flash Volatile Configuration Register

The FSM Serial Flash Controller is driven by issuing a standard set of
register writes we call a message sequence. This patch supplies a method
to prepare the message sequence responsible for updating a chip's VCR.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Provide a method to put the chip into 32bit addressing mode

Most Serial Flash chips support 24bit addressing as a default but more
recent incarnations can support 32bit. Based on information provided
though platform specific data and capabilities we can determine whether
or not our current chip can. This patch provides a means to setup the
FSM message sequence to put the chip into 32bit mode.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add a check to if the chip can handle an SoC reset

Based on information we can obtain though platform specific data and/or
chip capabilities we are able to determine whether or not we can handle
a SoC reset or not. To find out why this is important please read the
comment provided in the patch.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Prepare read/write sequences according to configuration

Firstly we search for our preference read/write configuration based on a
given chip's capabilities. Then we actually set up the message sequence
accordingly.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Provide the sequence for enabling 32bit addressing mode

The FSM Serial Flash Controller is driven by issuing a standard set of
register writes we call a message sequence. This patch supplies a method
to prepare the message sequence responsible for setting 32bit addressing
mode on the Flash chip.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Provide the erase one sector sequence

The FSM Serial Flash Controller is driven by issuing a standard set of
register writes we call a message sequence. This patch supplies a method
to prepare the message sequence responsible for erasing a single sector.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Fetch boot-device from mode pins

It's important for us to determine which device was used to boot from in
order to make some correct decisions surrounding Power Management. On
each of the platforms which support the FSM this is communicated via
a set of mode pins held in the system configuration area. This patch
determine the boot device and stores the result.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Prepare the read/write FSM message sequence(s)

The FSM Serial Flash Controller is driven by issuing a standard set of
register writes we call a message sequence. This patch supplies a method
to prepare read/write FSM message sequence(s) based on chip capability
and configuration.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Use device size to determine address width

Take some known parameters, namely size and number of sectors and use
them to determine weather a device can support 32bit addressing or not.
If it can, set the associated flash capability flag for latter use.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Search for preferred FSM message sequence configurations

Here we provide a means to traverse though all supplied FSM message
sequence configurations and pick one based on our chip's capabilities.
The first one we match will be the preferred one, as they are
presented in order of preference.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Dynamically setup flash device based on JEDEC ID

Using previously added infrastructure we can now extract a device's JEDEC
ID, compare it to a list of known and supported devices and make assumptions
based on known characteristics of a given chip.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Provide device look-up table

Supply a lookup table of all the devices we intend to support. This table
is used to store device information such as; a human readable device name,
their JEDEC ID (plus the extended version), sector size and amount, a bit
store of a device's capabilities, its maximum running frequency and
possible use of a per-device configuration call-back.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: devices: Provide header for shared OPCODEs and SFDP commands

JEDEC have helped to standardise a great deal of the commands which
can be issued to a Serial Flash devices. Many of the Serial Flash
Discoverable Parameters (SFDP) commands are generic across devices.
This patch provides a shared point where these commands can be
defined.

Suggested-by: Mark Brown <broonie@kernel.org>
Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Add support for JEDEC ID extraction

Once we start supporting devices it will be handy go detect them
dynamically. This will be done using the chip's unique JEDEC ID. This
patch allows us to extract a device's JEDEC ID using the a predefined
FSM register write sequence.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply a method to read from the FSM's FIFO

When invoked the driver will attempt to read any available data from
the FSM's data register. Any data collected from this FIFO would have
originated from the flash chip.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply framework for device requests

The FSM hardware works by setting a predetermined sequence of register
writes. Rather than open coding them inside each functional block we're
going to define them in a series of formatted 'sequence structures'.
This patch provides the framework which shall be used for every action.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Initialise and configure the FSM for normal working conditions

This patch uses default values to initialise a connected flash chip. This
includes; a device soft reset, setting of a safe working frequency, a
switch into Fast Sequencing Mode, configuring of timing data and a purge
of the FIFO.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Supply all register address and bit logic defines

Here we provide the FSM's register addresses, register bit names/offsets
and some commands which will prove useful as we start bulk the FMS's
driver out with functionality.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

mtd: st_spi_fsm: Allocate resources and register with MTD framework

This is a new driver. It's used to communicate with a special type of
optimised Serial Flash Controller called the FSM. The FSM uses a subset
of the SPI protocol to communicate with supported NOR-Flash devices.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>