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>

Drivers setting NAND_ECC_CUSTOM_PAGE_ACCESS are supposed to handle the
full read/write page sequence, and waiting for a page to actually be
programmed is part of this write-page sequence.
This is also what is done in ->write_oob_xxx() hooks, so let's do that in
->write_page_xxx() as well to make it consistent.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

SEQIN is supposed to be used when one wants to start programming a page.
What we want here is just to change the column within the page, which is
done with the RNDIN command.

Fixes: 6956e238 ("mtd: nand: add tango NAND flash controller support")
Cc: stable@vger.kernel.org
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>

The core already sends the NAND_CMD_READ0 for us. Duplicating this call
in the driver is useless and introduces a perf penalty.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

ecc->read_subpage is set to sunxi_nfc_hw_ecc_read_subpage_dma when
->dmac != NULL, but is then unconditionally overwritten in the common
init path.

Remove this extra assignment to allow usage of the DMA operation when
possible.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The ->errstat() hook is no longer implemented NAND controller drivers.
Get rid of it before someone starts abusing it.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Cached programming is always skipped, so drop the associated code until
we decide to really support it.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Provide a ->resume() hook to make sure the NAND timings are correctly
restored by resetting all chips connected to the controller.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The NAND controller IP can adapt the NAND controller timings dynamically.
Implement the ->setup_data_interface() hook to support this feature.

Note that it's not supported on at91rm9200 because this SoC has a
completely different SMC block, which is not supported yet.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Some NAND controllers can assign different NAND timings to different
CS lines. Pass the CS line information to ->setup_data_interface() so
that the NAND controller driver knows which CS line is concerned by
the setup_data_interface() request.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The only user of gpmi_nand_exit() is gpmi_nand_remove(). Move its content
to the caller.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Han Xu <han.xu@nxp.com>

The GPMI driver is wrongly assuming that nand_release() can safely be
called on an uninitialized/unregistered NAND device.

Add a new err_nand_cleanup label in the error path and only execute if
nand_scan_tail() succeeded.

Note that we now call nand_cleanup() instead of nand_release()
(nand_release() is actually grouping the mtd_device_unregister() and
nand_cleanup() in one call) because there's no point in trying to
unregister a device that has never been registered.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Han Xu <han.xu@nxp.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

The clock requirements are completely missing, add the clocks
currently required by the driver.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Add support for i.MX 7 SoC. The i.MX 7 has a slightly different
clock architecture requiring only two clocks to be referenced.
The IP is slightly different compared to i.MX 6, but currently none
of this differences are in use, therefore reuse GPMI_IS_MX6.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Add device specific list of clocks required, and handle all clocks
in a single for loop. This avoids further code duplication when
adding i.MX 7 support.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

If we see ~0UL in flash, there's no need for hweight, and no need to
check number of bitflips. So this should be net win.
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

This commit adjusts the fsmc_nand driver so that it accepts the
NAND_ECC_ON_DIE case. It simply does nothing in this case, since both
the ECC operations and OOB layout will be defined by the NAND chip code
rather than by the NAND controller code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Now that the core NAND subsystem has support for on-die ECC, this commit
brings the necessary code to support on-die ECC on Micron NANDs.

In micron_nand_init(), we detect if the Micron NAND chip supports on-die
ECC mode, by checking a number of conditions:

 - It must be an ONFI NAND
 - It must be a SLC NAND

 - Enabling *and* disabling on-die ECC must work

 - The on-die ECC must be correcting 4 bits per 512 bytes of data. Some
   Micron NAND chips have an on-die ECC able to correct 8 bits per 512
   bytes of data, but they work slightly differently and therefore we
   don't support them in this patch.

Then, if the on-die ECC cannot be disabled (some Micron NAND have on-die
ECC forcefully enabled), we bail out, as we don't support such
NANDs. Indeed, the implementation of raw_read()/raw_write() make the
assumption that on-die ECC can be disabled. Support for Micron NANDs
with on-die ECC forcefully enabled can easily be added, but in the
absence of such HW for testing, we preferred to simply bail out.

If the on-die ECC is supported, and requested in the Device Tree, then
it is indeed enabled, by using custom implementations of the
->read_page(), ->read_page_raw(), ->write_page() and ->write_page_raw()
operation to properly handle the on-die ECC.

In the non-raw functions, we need to enable the internal ECC engine
before issuing the NAND_CMD_READ0 or NAND_CMD_SEQIN commands, which is
why we set the NAND_ECC_CUSTOM_PAGE_ACCESS option at initialization
time (it asks the NAND core to let the NAND driver issue those
commands).
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

A lot of drivers are providing their own ->cmdfunc(), and most of the
time this implementation does not support all possible NAND operations.
But since ->cmdfunc() cannot return an error code, the core has no way
to know that the operation it requested is not supported.

This is a problem we cannot address for all kind of operations with the
current design, but we can prevent these silent failures for the
GET/SET FEATURES operation by overloading the default
->onfi_{set,get}_features() methods with one returning -ENOTSUPP.
Reported-by: Chris Packham <Chris.Packham@alliedtelesis.co.nz>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Chris Packham <Chris.Packham@alliedtelesis.co.nz>

The nand_read_page_raw() and nand_write_page_raw() functions might be
re-used by vendor-specific implementations of the read_page/write_page
functions. Instead of having vendor-specific code duplicate this code,
it is much better to export those functions and allow them to be
re-used.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

A number of NAND flashes have a capability called "on-die ECC" where the
NAND chip itself is capable of detecting and correcting errors.

Linux already has support for using the ECC implementation of the NAND
controller, or a software based ECC implementation, but not for using
the ECC implementation of the NAND controller. However, such an
implementation is sometimes useful in situations where the NAND
controller provides ECC algorithms that are not strong enough for the
NAND chip used on the system. A typical case is a NAND chip that
requires a 4-bit ECC, while the NAND controller only provides a 1-bit
ECC algorithm.

This commit introduces the support for the NAND_ECC_ON_DIE ECC mode:

 - Parsing of the "on-die" value for the "nand-ecc-mode" Device Tree
   property

 - Handling NAND_ECC_ON_DIE case in nand_scan_tail(). The idea is that
   the vendor specific code for the NAND chip must implement
   ->read_page() and ->write_page(). It may optionally provide its own
   ->read_page_raw() and ->write_page_raw() as well. For OOB operation,
   we assume the standard operations are good enough, but they can be
   overridden by the vendor specific code if needed.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

A number of NAND chips support a feature called on-die ECC, where the
NAND chip itself is capable of doing error detection and correction. The
new "on-die" value for nand-ecc-mode indicates that we want this
functionality to be used.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

When timings are no longer provided by the Device Tree, we now use the
SDR timings specified by the NAND flash, and such SDR timings are always
provided. Therefore, it is no longer necessary to keep "default" timings
in the fmsc driver.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Until now, the fsmc_nand driver was either using controller timings
specified in the Device Tree (through FSMC specific DT properties) or
alternatively default/fallback timings.

This commit implements support to use the timings advertised by the NAND
chip itself, by implementing the ->setup_data_interface() hook. To
preserve backward compatibility, if timings are specified in the Device
Tree, we use the timings from the Device Tree (and don't implement
->setup_data_interface).

Many thanks to Boris Brezillon for coming up with the logic to convert
the NAND chip timings into the timings expected by the FSMC controller.

Also, since the timings are now not only coming from the DT, the message
warning that default timings will be used is removed.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

In preparation for the introduction of support for using SDR timings
exposed by the NAND flash instead of hard-coded timings, this commit
reworks the fsmc_nand_setup() function to take a "struct fsmc_nand_data"
as argument, which already contains the I/O registers base address, bank
and bus width information.

The timings is also currently contained in the "struct fsmc_nand_data",
but we still pass it as a separate argument because the support for
using SDR timings will pass a different value.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

If ECC strength is 4bits/512bytes the algorithm of the ECC engine is
BCH, otherwise (1bit/512bytes) Hamming is used.
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

The mtd_set_ooblayout() accesor has been added to hide internals of
mtd_info and ease future refactoring. Call mtd_set_ooblayout() instead of
directly accessing mtd->ooblayout.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Harvey Hunt <harveyhuntnexus@gmail.com>