This function is wrong in multiple ways:

[1] Counting corrected bytes instead of corrected bits.

The following code is counting the number of corrected _bytes_.

    /* correct the ECC error */
    buf[offset] ^= err_cor_value;
    mtd->ecc_stats.corrected++;
    bitflips++;

What the core framework expects is the number of corrected _bits_.
They can be different if multiple bitflips occur within one byte.

[2] total number of errors instead of max of per-sector errors

The core framework expects that corrected errors are counted per
sector, then the max value should be taken.  The current code simply
iterates over the whole page, i.e. counts the total number of
correction in the page.  This means "too many bitflips" is triggered
earlier than it should be, i.e. the NAND device is worn out sooner.

Besides those bugs, this function is unreadable due to the deep
nesting.  Notice the whole code in this function is wrapped in
if (irq_status & INTR__ECC_ERR), so this conditional can be moved
out of the function.  Also, use shorter names for local variables.

Re-work the function to fix all the issues.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The pipeline read-ahead function of the Denali IP enables continuous
reading from the device; while data is being read out by a CPU, the
controller maintains additional commands for streaming data from the
device.  This will reduce the latency of the second page or later.

This feature is obviously no help for per-page accessors of Linux
NAND driver interface.

In the current implementation, the pipeline command is issued to
load a single page, then data are read out immediately.  The use of
the pipeline operation is not adding any advantage, but just adding
complexity to the code.  Remove.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Commit 28309572 ("mtd: name the mtd device with an optional
label property") allow us to identify a chip in a user-friendly way.

If nand_set_flash_node() picks up the "label" from DT, let's respect
it.  Otherwise, let it fallback to the current name "denali-nand".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Because SUPPORT_15BITECC is defined, the following is dead code:

  #elif SUPPORT_8BITECC
          iowrite32(8, denali->flash_reg + ECC_CORRECTION);
  #endif

Such ifdefs are useless and unacceptable coding style.

These writes are not needed in the first place since ECC_CORRECTION
is set up by the nand_init() function.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The write accesses to LOGICAL_PAGE_{DATA,SPARE}_SIZE have no effect
because the Denali User's Guide says these registers are read-only.

The hardware automatically multiplies the main/spare size by the
number of devices and update LOGICAL_PAGE_{DATA,SPARE}_SIZE.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Currently, the driver expects DEVICE_CONNECTED is automatically set
by the hardware, but this feature is disabled in some cases.
In such cases, it is the software's responsibility to set up the
DEVICES_CONNECTED register.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The available configuration of the IP bus width is x8 or x16, so the
possible value for denali->devnum is 1 or 2.

If the value is 1, there is nothing to do.  Fixup parameters only
when denali->devnum is 2.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Collect multi NAND fixups into a helper function instead of
scattering them in denali_init().

I am rewording the comment block to clearly explain what is called
"multi device".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

This will allow nand_dt_init() to parse DT properties in the NAND
controller device node.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The denali_init() needs to setup a bunch of parameters of nand_chip.
Replace denali->nand.(member) with chip->(member) for shorter code.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The interrupts are enabled by INTR_EN register, then asserted
interrupts can be observed via INTR_STATUS register.

The bit fields are identical between INTR_EN and INTR_STATUS, so we
can merge the bit field macros.  Likewise for DATA_INTR.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

This macro is defined twice in denali.c (around line 98 and
line 651), so remove the second one.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

All of these macros are not used at all.
CONFIG_MTD_NAND_DENALI_SCRATCH_REG_ADDR is not used for anything but
defining SCRATCH_REG_ADDR.  The config option should go away as well.

I am removing some register macros.  They are not used, and do not
exist in recent IP versions.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Such debug lines might be useful when debugging the driver first,
but should be deleted from the upstream code.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Remove parentheses surrounding the whole right side of an assignment.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The nand_scan_ident/tail() returns an appropriate error value when
it fails.  Use it instead of the fixed -ENXIO.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The devm_request_irq() returns an appropriate error value when it
fails.  Use it instead of the fixed -ENODEV.

While we are here, reword the comment to make it fit in a single
line, fixing the misspelling of "initialization".
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Use the managed variant instead of request_irq() and free_irq().
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The denali->blksperchip is set, but not referenced any more.  The
denali->totalblks is used only for calculating denali->blksperchip.
Both of them are unneeded.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

As far as I understood from the Kconfig menu deleted by commit
be7f39c5 ("Staging: delete spectra driver"), the "Spectra" is
specific to Intel Moorestown Platform.

The Denali NAND controller IP is used for various SoCs such as
Altera SOCFPGA, Socionext UniPhier, etc.  The platform specific
strings are not preferred in this driver.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The denali->fwblks is set by detect_partition_feature(), but it is
not referenced from anywhere.  That means the struct member fwblks
and the whole of detect_partition_feature() are unneeded.

The comment block implies this function is only for Intel platforms.
I found drivers/staging/spectra used to exist, but it was deleted by
commit be7f39c5 ("Staging: delete spectra driver") 5 years ago.

So, I guess nobody would need this function any more.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The interrupt handler is setup in denali_init(), not in
denali_drv_init().  This comment is false.

Such a comment adds no value, so just delete it instead of move.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The struct member "idx" was used as an index for debug_array long
ago, but the DEBUG_DENALI feature was removed by commit 7cfffac0
("nand/denali: use dev_xx debug function to replace nand_dbg_print
and some printk").  Since then, this has been only initialized, but
never referenced.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The driver calls devm_kzalloc()/devm_kfree() to allocate/free memory.
They are declared in <linux/device.h>, not in <linux/slab.h>.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMarek Vasut <marek.vasut@gmail.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

Implementing the mtd_ooblayout_ops interface is the new way of exposing
ECC/OOB layout to MTD users.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

mtd_to_nand() now uses the container_of() approach to transform an
mtd_info pointer into a nand_chip one. Drop useless mtd->priv
assignments from NAND controller drivers.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

struct nand_chip now embeds an mtd device. Make use of this mtd instance.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

Unregister the NAND device from the NAND subsystem when removing a denali
NAND controller, otherwise the MTD attached to the NAND device is still
exposed by the MTD layer, and accesses to this device will likely crash
the system.

Fixes: 2a0a288e ("mtd: denali: split the generic driver and PCI layer")
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: NDinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The ->read_xxx() methods are all passed the page number the NAND controller
is supposed to read, but ->write_xxx() do not have such a parameter.

This is a problem if we want to properly implement data
scrambling/randomization in order to mitigate MLC sensibility to repeated
pattern: to prevent bitflips in adjacent pages in the same block we need
to avoid repeating the same pattern at the same offset in those pages,
hence the randomizer/scrambler engine need to be passed the page value
in order to adapt its seed accordingly.

Moreover, adding the page parameter to the ->write_xxx() methods add some
consistency to the current API.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
CC: Josh Wu <josh.wu@atmel.com>
CC: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
CC: Maxime Ripard <maxime.ripard@free-electrons.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Huang Shijie <shijie.huang@arm.com>
CC: Stefan Agner <stefan@agner.ch>
CC: devel@driverdev.osuosl.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

Owner is automatically set by mtdcore. Make use of that.
Signed-off-by: NFrans Klaver <fransklaver@gmail.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

Read Denali hardware revision number and use it to
calculate max_banks,  The encoding of max_banks changed
in Denali revision 5.1.
Signed-off-by: NGraham Moore <grmoore@opensource.altera.com>
[Brian: parentheses around macro arg]
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

A read id operation followed by 0x00 reads the device ID while
a read id operation followed by 0x20 reads the possible ONFI identifier.

As the READID function did not propagate the second id parameter but had
a hard-coded call for 0x90 0x00, reading the ONFI identifier was not
possible and thus chips werde not detected (tested with
MT29F8G08ABABAWP)
Signed-off-by: NEnrico Jorns <ejo@pengutronix.de>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The Denali Controller IP does not support sub-page writes.
Signed-off-by: NGraham Moore <grmoore@opensource.altera.com>
Signed-off-by: NDinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

TclsRising is always 1.

Caught by Coverity.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>

This driver uses NAND_ECC_HW_SYNDROME mode.  The nand_scan_tail()
function would not complain about missing ecc->calculate,
ecc->correct, ecc->hwctl handlers.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

commit 3157d1ed ("mtd: denali: remove unnecessary casts") introduced
an error by using a wrong bitmask.

A uint16_t cast was replaced with & 0xff, should be & 0xffff.
Signed-off-by: NGraham Moore <grmoore@opensource.altera.com>
Signed-off-by: NDinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

- Fix indents
- Do not break a line unless it is longer than 80 columns
- Do not insert a whitespace before ';'
- Use whitespaces around operators
- Use braces for a "else" block where the "if" block uses ones.

Besides, eliminate all the warnings reported by checkpatch.pl:
- WARNING: quoted string split across lines
- WARNING: else is not generally useful after a break or return
- WARNING: Missing a blank line after declarations
- WARNING: Avoid line continuations in quoted strings
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

We should use parentheses only when they are necessary
or they really improve the readability.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The variable "irq_status" in denali_read_page_raw() is set, but not used.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The variable "retry" in wait_for_irq() is set, but not used.
Signed-off-by: NMasahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>