Currently, we trigger ECC HW before setting ecc irq. It is incorrect.
Because ECC starts working once the register ECC_CTL_REG is set as
ECC_OP_ENABLE. And this may lead an abnormal behavior of ecc irq.
So, should enable ecc irq at first, then trigger ECC.

Fixes: 1d6b1e46 ("mtd: mediatek: driver for MTK Smart Device")
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The Denali NAND controller driver (drivers/mtd/nand/denali*) has been
largely reworked by me.  Add myself as its maintainer now.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The binding bus/ti-gpmc.txt has been moved to
memory-controllers/omap-gpmc.txt.  Update all references to this in
order to make reading and understanding a given binding easier.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc:Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The binding says that the compatible string must be "ti,am33xx-elm"
but the code checks only for, and all functioning users set, this as
"ti,am3352-elm" so correct the binding.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

All IFC version >= 1.0 use 28nm technology for SRAM. Here SRAM has
a requirement to initialize before any read operation performed for
avoiding ECC Error.

So update condition check to initialize SRAM for all IFC version >= 1.0.0
Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Introduce some macros and helpers to avoid magic numbers and
rename macros/functions for clarification.

- We see '| 2' in several places.  This means Data Cycle in MAP11 mode.
  The Denali User's Guide says bit[1:0] of MAP11 is like follows:

  b'00 = Command Cycle
  b'01 = Address Cycle
  b'10 = Data Cycle

  So, this commit added DENALI_MAP11_{CMD,ADDR,DATA} macros.

- We see 'denali->flash_mem + 0x10' in several places, but 0x10 is a
  magic number.  Actually, this accesses the data port of the Host
  Data/Command Interface.  So, this commit added DENALI_HOST_DATA.
  On the other hand, 'denali->flash_mem' gets access to the address
  port, so DENALI_HOST_ADDR was also added.

- We see 'index_addr(denali, cmd, 0x1)' in denali_erase(), but 0x1
  is a magic number.  0x1 means the erase operation.  Replace 0x1
  with DENALI_ERASE.

- Rename index_addr() to denali_host_write() for clarification

- Denali User's Guide says MAP{00,01,10,11} for access mode.  Match
  the macros with terminology in the IP document.

- Rename struct members as follows:
  flash_bank   -> active_bank    (currently selected bank)
  flash_reg    -> reg            (base address of registers)
  flash_mem    -> host           (base address of host interface)
  devnum       -> devs_per_cs    (devices connected in parallel)
  bbtskipbytes -> oob_skip_bytes (number of bytes to skip in OOB)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Now this driver is ready to remove NAND_SKIP_BBTSCAN.

The BBT descriptors in denali.c are equivalent to the ones in
nand_bbt.c.  There is no need to duplicate the equivalent structures.
The with-oob decriptors do not work for this driver anyway.

The bbt_pattern (offs = 8) and the version (veroffs = 12) area
overlaps the ECC area.  Set NAND_BBT_NO_OOB flag to use the no_oob
variant of the BBT descriptors.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

As Russell and Lars stated in the discussion [1], using
devm_k*alloc() with DMA is not a good idea.

Let's use kmalloc (not kzalloc because no need for zero-out).
Also, allocate the buffer as late as possible because it must be
freed for any error that follows.

[1] https://lkml.org/lkml/2017/3/8/693Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

For ecc->read_page() and ecc->write_page(), it is possible to call
dma_map_single() against the given buffer.  This bypasses the driver
internal bounce buffer and save the memcpy().
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Recent versions of this IP support automatic erased page detection.
If an erased page is detected on reads, the controller does not set
INTR__ECC_UNCOR_ERR, but INTR__ERASED_PAGE.

The detection of erased pages is based on the number of zeros in a
page; if the number of zeros is less than the value in the field
ERASED_THRESHOLD, the page is assumed as erased.

Please note ERASED_THRESHOLD specifies the number of zeros in a _page_
instead of an ECC chunk.  Moreover, the controller does not provide a
way to know the actual number of bitflips.

Actually, an erased page (all 0xff) is not an ECC correctable pattern
on the Denali ECC engine.  In other words, there may be overlap between
the following two:

[1] a bit pattern reachable from a valid payload + ECC pattern within
    ecc.strength bitflips
[2] a bit pattern reachable from an erased state (all 0xff) within
    ecc.strength bitflips

So, this feature may intercept ECC correctable patterns, then replace
[1] with [2].

After all, this feature can work safely only when ECC_THRESHOLD == 1,
i.e. detect erased pages without any bitflips.  This should be the
case most of the time.  If there is a bitflip or more, the driver will
fallback to the software method by using nand_check_erased_ecc_chunk().

Strangely enough, the driver still has to fill the buffer with 0xff
in case of INTR__ERASED_PAGE because the ECC correction engine has
already manipulated the data in the buffer before it judges erased
pages.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The Denali IP adopts the syndrome page layout; payload and ECC are
interleaved, with BBM area always placed at the beginning of OOB.

The figure below shows the page organization for ecc->steps == 2:

  |----------------|    |-----------|
  |                |    |           |
  |                |    |           |
  |    Payload0    |    |           |
  |                |    |           |
  |                |    |           |
  |                |    |           |
  |----------------|    |  in-band  |
  |      ECC0      |    |   area    |
  |----------------|    |           |
  |                |    |           |
  |                |    |           |
  |    Payload1    |    |           |
  |                |    |           |
  |                |    |           |
  |----------------|    |-----------|
  |      BBM       |    |           |
  |----------------|    |           |
  |Payload1 (cont.)|    |           |
  |----------------|    |out-of-band|
  |      ECC1      |    |    area   |
  |----------------|    |           |
  |    OOB free    |    |           |
  |----------------|    |-----------|

The current raw / oob accessors do not take that into consideration,
so in-band and out-of-band data are transferred as stored in the
device.  In the case above,

  in-band:      Payload0 + ECC0 + Payload1(partial)
  out-of-band:  BBM + Payload1(cont.) + ECC1 + OOB-free

This is wrong.  As the comment block of struct nand_ecc_ctrl says,
driver callbacks must hide the specific layout used by the hardware
and always return contiguous in-band and out-of-band data.

The current implementation is completely screwed-up, so read/write
callbacks must be re-worked.

Also, it is reasonable to support PIO transfer in case DMA may not
work for some reasons.  Actually, the Data DMA may not be equipped
depending on the configuration of the RTL.  This can be checked by
reading the bit 4 of the FEATURES register.  Even if the controller
has the DMA support, dma_set_mask() and dma_map_single() could fail.
In either case, the driver can fall back to the PIO transfer.  Slower
access would be better than giving up.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

It is not a good idea to re-use macros that represent a specific
register bit field for the transfer direction.

It is true that bit 8 indicates the direction for the MAP10 pipeline
operation and the data DMA operation, but this is not valid across
the IP.

Use a simple flag (write: 1, read: 0) for the direction.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Now struct nand_buf has only two members, so I see no reason for the
separation.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

This driver stores the currently addressed page into denali->page,
which is later read out by helper functions.  While I am tackling on
this driver, I often missed to insert "denali->page = page;" where
needed.  This makes page_read/write callbacks to get access to a
wrong page, which is a bug hard to figure out.

Instead, I'd rather pass the page via function argument because the
compiler's prototype checks will help to detect bugs.

For the same reason, propagate dma_addr to the DMA helpers instead
of denali->buf.dma_buf .
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The current bank reset implementation polls the INTR_STATUS register
until interested bits are set.  This is not good because:

- polling simply wastes time-slice of the thread

- The while() loop may continue eternally if no bit is set, for
  example, due to the controller problem.  The denali_wait_for_irq()
  uses wait_for_completion_timeout(), which is safer.

We can use interrupt by moving the denali_reset_bank() call below
the interrupt setup.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The nand_scan_ident() iterates over maxchips, and calls nand_reset()
for each.  This driver currently passes the maximum number of banks
(=chip selects) supported by the controller as maxchips.  So, maxchips
is typically 4 or 8.  Usually, less number of NAND chips are connected
to the controller.

This can be a problem for ONFi devices.  Now, this driver implements
->setup_data_interface() hook, so nand_setup_data_interface() issues
Set Features (0xEF) command, which waits until the chip returns R/B#
response.  If no chip there, we know it never happens, but the driver
still ends up with waiting for a long time.  It will finally bail-out
with timeout error and the driver will work with existing chips, but
unnecessary wait will give a bad user experience.

The denali_nand_reset() polls the INTR__RST_COMP and INTR__TIME_OUT
bits, but they are always set even if not NAND chip is connected to
that bank.  To know the chip existence, INTR__INT_ACT bit must be
checked; this flag is set only when R/B# is toggled.  Since the Reset
(0xFF) command toggles the R/B# pin, this can be used to know the
actual number of chips, and update denali->max_banks.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The NAND_CMD_SET_FEATURES support is missing from denali_cmdfunc().
We also see /* TODO: Read OOB data */ comment.

It would be possible to add more commands along with the current
implementation, but having ->cmd_ctrl() seems a better approach from
the discussion with Boris [1].

Rely on the default ->cmdfunc() from the framework and implement the
driver's own ->cmd_ctrl().

This transition also fixes NAND_CMD_STATUS and NAND_CMD_PARAM handling.
NAND_CMD_STATUS was just faked by the register read, so the only valid
bit was the WP bit.  NAND_CMD_PARAM was completely broken; not only the
command sent on the bus was NAND_CMD_STATUS instead of NAND_CMD_PARAM,
but also the driver was only reading 8 bytes, while the parameter page
contains several hundreds of bytes.

Also add ->write_byte(), which is needed for write direction commands,
->read/write_buf(16), which will be used some commits later.
->read_word() is not used for now, but the core may call it in the
future.

Now, this driver can drop nand_onfi_get_set_features_notsupp().

[1] https://lkml.org/lkml/2017/3/15/97Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Simplify the interrupt handling and fix issues:

- The register field view of INTR_EN / INTR_STATUS is different
  among IP versions.  The global macro DENALI_IRQ_ALL is hard-coded
  for Intel platforms.  The interrupt mask should be determined at
  run-time depending on the running platform.

- wait_for_irq() loops do {} while() until interested flags are
  asserted.  The logic can be simplified.

- The spin_lock() guard seems too complex (and suspicious in a race
  condition if wait_for_completion_timeout() bails out by timeout).

- denali->complete is reused again and again, but reinit_completion()
  is missing.  Add it.

Re-work the code to make it more robust and easier to handle.

While we are here, also rename the jump label "failed_req_irq" to
more appropriate "disable_irq".
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Handling timing parameters in a driver's own way should be avoided
because it duplicates efforts of drivers/mtd/nand/nand_timings.c
Besides, this driver hard-codes Intel specific parameters such as
CLK_X=5, CLK_MULTI=4.  Taking a certain device (Samsung K9WAG08U1A)
into account by get_samsung_nand_para() is weird as well.

Now, the core framework provides .setup_data_interface() hook, which
handles timing parameters in a generic manner.

While I am working on this, I found even more issues in the current
code, so fixed the following as well:

- In recent IP versions, WE_2_RE and TWHR2 share the same register.
  Likewise for ADDR_2_DATA and TCWAW, CS_SETUP_CNT and TWB.  When
  updating one, the other must be masked.  Otherwise, the other will
  be set to 0, then timing settings will be broken.

- The recent IP release expanded the ADDR_2_DATA to 7-bit wide.
  This register is related to tADL.  As commit 74a332e7 ("mtd:
  nand: timings: Fix tADL_min for ONFI 4.0 chips") addressed, the
  ONFi 4.0 increased the minimum of tADL to 400 nsec.  This may not
  fit in the 6-bit ADDR_2_DATA in older versions.  Check the IP
  revision and handle this correctly, otherwise the register value
  would wrap around.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The function find_valid_banks() issues the Read ID (0x90) command,
then compares the first byte (Manufacturer ID) of each bank with
the one of bank0.

This is equivalent to what nand_scan_ident() does.  The number of
chips is detected there, so this is unneeded.

What is worse for find_valid_banks() is that, if multiple chips are
connected to INTEL_CE4100 platform, it crashes the kernel by BUG().
This is what we should avoid.  This function is just harmful and
unneeded.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The denali_cmdfunc() actually does nothing valuable for
NAND_CMD_{PAGEPROG,READ0,SEQIN}.

For NAND_CMD_{READ0,SEQIN}, it copies "page" to "denali->page", then
denali_read_page(_raw) compares them just for the sanity check.
(Inconsistently, this check is missing from denali_write_page(_raw).)

The Denali controller is equipped with high level read/write interface,
so let's skip unneeded call of cmdfunc().

If NAND_ECC_CUSTOM_PAGE_ACCESS is set, nand_write_page() will not
call ->waitfunc hook.  So, ->write_page(_raw) hooks should directly
return -EIO on failure.  The error handling of page writes will be
much simpler.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The Atmel NAND driver doesn't used anything from
linux/platform_data/atmel.h, stop including it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Add two compatible strings for UniPhier SoC family.

"socionext,uniphier-denali-nand-v5a" is used on UniPhier sLD3, LD4,
Pro4, sLD8.

"socionext,uniphier-denali-nand-v5b" is used on UniPhier Pro5, PXs2,
LD6b, LD11, LD20.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The Denali IP can automatically detect device parameters such as
page size, oob size, device width, etc. and this driver currently
relies on it.  However, this hardware function is known to be
problematic.

[1] Due to a hardware bug, various misdetected cases were reported.
    That is why get_toshiba_nand_para() and get_hynix_nand_para()
    exist to fix-up the misdetected parameters.  It is not realistic
    to add a new NAND device to the *black list* every time we are
    hit by a misdetected case.  We would never be able to guarantee
    that all cases are covered.

[2] Because this feature is unreliable, it is disabled on some
    platforms.

The nand_scan_ident() detects device parameters in a more tested
way.  The hardware should not set the device parameter registers in
a different, unreliable way.  Instead, set the parameters from the
nand_scan_ident() back to the registers.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

This driver was originally written for the Intel MRST platform with
several platform-specific parameters hard-coded.

Currently, the ECC settings are hard-coded as follows:

  #define ECC_SECTOR_SIZE 512
  #define ECC_8BITS       14
  #define ECC_15BITS      26

Therefore, the driver can only support two cases.
 - ecc.size = 512, ecc.strength = 8    --> ecc.bytes = 14
 - ecc.size = 512, ecc.strength = 15   --> ecc.bytes = 26

However, these are actually customizable parameters, for example,
UniPhier platform supports the following:

 - ecc.size = 1024, ecc.strength = 8   --> ecc.bytes = 14
 - ecc.size = 1024, ecc.strength = 16  --> ecc.bytes = 28
 - ecc.size = 1024, ecc.strength = 24  --> ecc.bytes = 42

So, we need to handle the ECC parameters in a more generic manner.
Fortunately, the Denali User's Guide explains how to calculate the
ecc.bytes.  The formula is:

  ecc.bytes = 2 * CEIL(13 * ecc.strength / 16)  (for ecc.size = 512)
  ecc.bytes = 2 * CEIL(14 * ecc.strength / 16)  (for ecc.size = 1024)

For DT platforms, it would be reasonable to allow DT to specify ECC
strength by either "nand-ecc-strength" or "nand-ecc-maximize".  If
none of them is specified, the driver will try to meet the chip's ECC
requirement.

For PCI platforms, the max ECC strength is used to keep the original
behavior.

Newer versions of this IP need ecc.size and ecc.steps explicitly
set up via the following registers:
  CFG_DATA_BLOCK_SIZE       (0x6b0)
  CFG_LAST_DATA_BLOCK_SIZE  (0x6c0)
  CFG_NUM_DATA_BLOCKS       (0x6d0)

For older IP versions, write accesses to these registers are just
ignored.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

struct nand_ecc_caps was designed as flexible as possible to support
multiple stepsizes (like sunxi_nand.c).

So, we need to write multiple arrays even for the simplest case.
I guess many controllers support a single stepsize, so here is a
shorthand macro for the case.

It allows to describe like ...

NAND_ECC_CAPS_SINGLE(denali_pci_ecc_caps, denali_calc_ecc_bytes, 512, 8, 15);

... instead of

static const int denali_pci_ecc_strengths[] = {8, 15};
static const struct nand_ecc_step_info denali_pci_ecc_stepinfo = {
        .stepsize = 512,
        .strengths = denali_pci_ecc_strengths,
        .nstrengths = ARRAY_SIZE(denali_pci_ecc_strengths),
};
static const struct nand_ecc_caps denali_pci_ecc_caps = {
        .stepinfos = &denali_pci_ecc_stepinfo,
        .nstepinfos = 1,
        .calc_ecc_bytes = denali_calc_ecc_bytes,
};
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Driver are responsible for setting up ECC parameters correctly.
Those include:
  - Check if ECC parameters specified (usually by DT) are valid
  - Meet the chip's ECC requirement
  - Maximize ECC strength if NAND_ECC_MAXIMIZE flag is set

The logic can be generalized by factoring out common code.

This commit adds 3 helpers to the NAND framework:
nand_check_ecc_caps - Check if preset step_size and strength are valid
nand_match_ecc_req - Match the chip's requirement
nand_maximize_ecc - Maximize the ECC strength

To use the helpers above, a driver needs to provide:
  - Data array of supported ECC step size and strength
  - A hook that calculates ECC bytes from the combination of
    step_size and strength.

By using those helpers, code duplication among drivers will be
reduced.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Use BIT() and GENMASK() for register field macros.  This will make
it easier to compare the macros with the register description in the
Denali User's Guide.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

No need to use two struct resource pointers.  Just reuse one.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Signed-off-by: Matthias Lange <matthias.lange@kernkonzept.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

This makes it easier to grep.
Signed-off-by: Matthias Lange <matthias.lange@kernkonzept.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

clk_prepare_enable() can fail here and we must check its return value.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

If we see unrecoverable ECC error, we need to count number of bitflips
from all-ones and report correctable/uncorrectable according to
that. Otherwise we report ECC failed on erased flash with single bit error.
Signed-off-by: Pavel Machek <pavel@denx.de>
Reported-by: Darwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Acked-by: Darwin Dingel <Darwin.Dingel@alliedtelesis.co.nz>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

MT2712 NAND FLASH Controller is similar to MT2701 except those following:
(1) MT2712 supports up to 148B spare size per 1KB size sector (the same
    with 74B spare size per 512B size sector). There are three new spare
    format: 61, 67, 74.
(2) MT2712 supports up to 80 bit ecc strength. There are three new ecc
    strength level: 68, 72, 80.
(3) MT2712 ECC encode parity data register's start offset is 0x300, and
    different with 0x10 of MT2701.
(4) MT2712 improves ecc irq function. When ECC works in ECC_NFI_MODE,
    MT2701 will generate ecc irq number the same with ecc steps during
    page read. However, MT2712 can only generate one ecc irq.

Changes of this patch are:
(1) add two new variables named pg_irq_sel, encode_parity_reg0 in struct
    mtk_ecc_caps.
(2) add new bitfield ECC_PG_IRQ_SEL for register ECC_IRQ_REG.
(3) add ecc strength array of mt2712.
(4) add spare size array of mt2712.
(5) add mt2712 nfc and ecc device compatiable and data.
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

ECC strength and spare size supported may be different among MTK NAND
FLASH Controller IPs.

This patch contains changes as following:
(1) add new struct mtk_nfc_caps to support different spare size.
(2) add new struct mtk_ecc_caps to support different ecc strength.
(3) remove ECC_CNFG_xBIT define, use a for loop to do ecc strength config.
(4) remove PAGEFMT_SPARE_ define, use a for loop to do spare format config.
(5) malloc ecc->eccdata buffer according to max ecc strength of this IP.
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The register NFI_PAGEFMT is always 32 bits length, so it is better to
do register program using writel() compare with writew().
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Add MT2712 NAND Flash Controller dt bindings documentation.
Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The newly added suspend/resume support causes a harmless warning:

drivers/mtd/nand/atmel/nand-controller.c:2513:12: error: 'atmel_nand_controller_resume' defined but not used [-Werror=unused-function]

This shuts up the warning with a __maybe_unused annotation.

Fixes: b107007a7114 ("mtd: nand: atmel: Add PM ops")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Drivers are supposed to set correct ecc->{size,strength,bytes} before
calling nand_scan_tail(), but it does not complain about ecc->total
bigger than oobsize.

In this case, chip->scan_bbt() crashes due to memory corruption, but
it is hard to debug.  It would be kind to fail it earlier with a clear
message.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

READ0 is sometimes used to exit GET STATUS mode. When this is the case
no address cycles are requested, and we can use this information to
detect that READSTART should not be issued after READ0 or that we
shouldn't wait for the chip to be ready.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>