nand_do_write_ops() determines if it is writing a partial page with the
formula:
part_pagewr = (column || writelen < (mtd->writesize - 1))
When 'writelen' is exactly 1 byte less than the NAND page size the formula
equates to zero, so the code doesn't process it as a partial write,
although it should.
As a consequence the function remains in the while(1) loop with 'writelen'
becoming 0xffffffff and iterating endlessly.
The bug may not be easy to reproduce in Linux since user space tools
usually force the padding or round-up the write size to a page-size
multiple.
This was discovered in U-Boot where the issue can be reproduced by
writing any size that is 1 byte less than a page-size multiple.
For example, on a NAND with 2K page (0x800):
=> nand erase.part <partition>
=> nand write $loadaddr <partition> 7ff
[Editor's note: the bug was added in commit 29072b9607, but moved
around in commit 66507c7bc8 ("mtd: nand: Add support to use nand_base
poi databuf as bounce buffer")]
Fixes: 29072b9607 ("[MTD] NAND: add subpage write support")
Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
* introduction of the ECC algo concept to extend the ECC mode one
* replacement of the nand_ecclayout infrastructure by something more
future-proof.
* addition of an mtd-activity led trigger to replace the nand-activity
one
And a bunch of specific NAND driver improvements/fixes. Here are the
changes that are worth mentioning:
* rework of the OMAP GPMC and NAND drivers
* prepare the sunxi NAND driver to receive DMA support
* handle bitflips in erased pages on GPMI revisions that do not support
this in hardware.
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Merge tag 'nand/for-4.7' of github.com:linux-nand/linux
Updates from Boris Brezillon:
This pull request contains the following infrastructure changes:
* introduction of the ECC algo concept to extend the ECC mode one
* replacement of the nand_ecclayout infrastructure by something more
future-proof.
* addition of an mtd-activity led trigger to replace the nand-activity
one
And a bunch of specific NAND driver improvements/fixes. Here are the
changes that are worth mentioning:
* rework of the OMAP GPMC and NAND drivers
* prepare the sunxi NAND driver to receive DMA support
* handle bitflips in erased pages on GPMI revisions that do not support
this in hardware.
* tag 'nand/for-4.7' of github.com:linux-nand/linux: (152 commits)
mtd: brcmnand: respect ECC algorithm set by NAND subsystem
gpmi-nand: Handle ECC Errors in erased pages
Documentation: devicetree: deprecate "soft_bch" nand-ecc-mode value
mtd: nand: add support for "nand-ecc-algo" DT property
mtd: mtd: drop NAND_ECC_SOFT_BCH enum value
mtd: drop support for NAND_ECC_SOFT_BCH as "soft_bch" mapping
mtd: nand: read ECC algorithm from the new field
mtd: nand: fsmc: validate ECC setup by checking algorithm directly
mtd: nand: set ECC algorithm to Hamming on fallback
staging: mt29f_spinand: set ECC algorithm explicitly
CRIS v32: nand: set ECC algorithm explicitly
mtd: nand: atmel: set ECC algorithm explicitly
mtd: nand: davinci: set ECC algorithm explicitly
mtd: nand: bf5xx: set ECC algorithm explicitly
mtd: nand: omap2: Fix high memory dma prefetch transfer
mtd: nand: omap2: Start dma request before enabling prefetch
mtd: nandsim: add __init attribute
mtd: nand: move of_get_nand_xxx() helpers into nand_base.c
mtd: nand: sh_flctl: rely on generic DT parsing done in nand_scan_ident()
mtd: nand: mxc: rely on generic DT parsing done in nand_scan_ident()
...
So far it was only possible to specify ECC algorithm using "soft" and
"soft_bch" values of nand-ecc-mode prop. There wasn't a way to specify
it for a hardware ECC mode.
Now that we have independent field in NAND subsystem for storing info
about ECC algorithm we may also add support for this new DT property.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This value should not be part of nand_ecc_modes_t as it specifies
algorithm not a mode. We successfully managed to introduce new "algo"
field which is respected now.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
There isn't any difference between handling NAND_ECC_SOFT and
NAND_ECC_SOFT_BCH now. What matters is the new field called "algo".
Please note we're keeping backward DT compatibility. We are still
treating "soft_bch" value as the one setting Hamming algorithm, it's
just handled in of_get_nand_ecc_algo now.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Now we have all drivers properly setting this new field we can start
using it. For a very short period of time we should support both values:
NAND_ECC_SOFT and NAND_ECC_SOFT_BCH treating them the same. It's because
of_get_nand_ecc_mode may still be setting NAND_ECC_SOFT_BCH.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This is part of process deprecating NAND_ECC_SOFT_BCH (and switching to
enum nand_ecc_algo).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Now that all drivers go through nand_set_flash_node() to parse the generic
NAND properties, we can move all of_get_nand_xxx() helpers in to
nand_base.c, make them static and remove of_mtd.c and of_mtd.h.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Now that all NAND drivers have switched to mtd_ooblayout_ops, we can kill
the ecc->layout field.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Replace the nand_ecclayout definition by the equivalent mtd_ooblayout_ops
definition.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Replace the default nand_ecclayout definitions for large and small page
devices with the equivalent mtd_ooblayout_ops.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Use the mtd_set_ecclayout() helper instead of directly assigning the
mtd->ecclayout field.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
The mtd_ooblayout_xxx() helper functions have been added to avoid direct
accesses to the ecclayout field, and thus ease for future reworks.
Use these helpers in all places where the oobfree[] and eccpos[] arrays
where directly accessed.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Export the default read/write oob functions (for the standard and syndrome
scheme), so that drivers can use them for their raw implementation and
implement their own functions for the normal oob operation.
This is required if your ECC engine is capable of fixing some of the OOB
data. In this case you have to overload the ->read_oob() and ->write_oob(),
but if you don't specify the ->read/write_oob_raw() functions they are
assigned to the ->read/write_oob() implementation, which is not what you
want.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
There's no reason to BUG() when parameters are being
validated. Drivers can get things wrong, and it's much nicer
to just throw a noisy warn and fail gracefully, than calling
BUG() and throwing the whole system down the drain.
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Use recently added of_get_nand_ecc_algo for that.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit removes the "nand-disk" LED trigger from the
NAND code.
A trigger with the same name is already available selecting
LEDS_TRIGGER_MTD. Note that "nand-disk" trigger is being
deprecated in favor of the "mtd" trigger.
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Since commit 807f16d4db ("mtd: core: set some defaults
when dev.parent is set"), it's now legal for drivers
to call nand_scan and nand_scan_ident without setting
mtd.owner.
Drop the check and while at it remove the BUG() abuse.
Fixes: 807f16d4db ("mtd: core: set some defaults when dev.parent is set")
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[Brian: editorial note - while commit 807f16d4db wasn't explicitly
broken, some follow-up commits in the v4.4 release broke a few
drivers, since they would hit this BUG() if they used nand_scan()
and were built as modules]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
The 'getchip' parameter is gone as of commit 9f3e04297b ("mtd: nand:
don't select chip in nand_chip's block_bad op"), so kill the doc with
it.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
One of the arguments passed to struct nand_chip's block_bad op is
'getchip', which, if true, is supposed to get and select the nand device,
and later unselect and release the device.
This op is intended to be replaceable by drivers. The drivers shouldn't
be responsible for selecting/unselecting chip. Like other ops, the chip
should already be selected before the block_bad op is called.
Remove the getchip argument from the block_bad op and
nand_block_checkbad. Move the chip selection to nand_block_isbad, since it
is the only caller to nand_block_checkbad which requires chip selection.
Modify nand_block_bad (the default function for the op) such that it
doesn't select the chip.
Remove the getchip argument from the bad_block funcs in cafe_nand,
diskonchip and docg4 drivers.
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
nand_bch_init() requires several arguments which could directly be deduced
from the mtd device. Get rid of those useless parameters.
nand_bch_init() is also requiring the caller to provide a proper eccbytes
value, while this value could be deduced from the ecc.size and
ecc.strength value. Fallback to eccbytes calculation when it is set to 0.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Currently, all MTD drivers/sublayers exposing an OOB area are
doing the same kind of test to extract the available OOB size
based on the mtd_info and mtd_oob_ops structures.
Move this common logic into an inline function and make use of it.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Suggested-by: Priit Laes <plaes@plaes.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
ecclayout->oobavail is just redundant with the mtd->oobavail field.
Moreover, it prevents static const definition of ecc layouts since the
NAND framework is calculating this value based on the ecclayout->oobfree
field.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
In commit b70af9bef4 ("mtd: nand: increase ready wait timeout and
report timeouts"), we increased the likelihood of scheduling during
nand_wait(). This makes us more likely to hit the time_before(...)
condition, since a lot of time may pass before we get scheduled again.
Now, the loop was already buggy, since we don't check if the NAND is
ready after exiting the loop; we simply print out a timeout warning. Fix
this by doing a final status check before printing a timeout message.
This isn't actually a critical bug, since the only effect is a false
warning print. But too many prints never hurt anyone, did they? :)
Side note: perhaps I'm not smart enough, but I'm not sure what the best
policy is for this kind of loop; do we busy loop (i.e., no
cond_resched()) to keep the lowest I/O latency (it's not great if the
resched is delaying Richard's system ~400ms)? Or do we allow
rescheduling, to play nice with the rest of the system (since some
operations can take quite a while)?
Reported-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Harvey Hunt <harvey.hunt@imgtec.com>
The default NAND read functions are relying on the underlying controller
driver to correct bitflips, but some of those controllers cannot properly
fix bitflips in erased pages.
Check for bitflips in erased pages in default core functions if the driver
delegated the this check by setting the NAND_ECC_GENERIC_ERASED_CHECK flag.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Franklin S Cooper Jr. <fcooper@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Commits such as commit 853f1c58c4 ("mtd: nand: omap2: show parent
device structure in sysfs") attempt to rely on the core MTD code to set
the MTD name based on the parent device. However, nand_base tries to set
a different default name according to the flash name (e.g., extracted
from the ONFI parameter page), which means NAND drivers will never make
use of the MTD defaults. This is not the intention of commit
853f1c58c4.
This results in problems when trying to use the cmdline partition
parser, since the MTD name is different than expected. Let's fix this by
providing a default NAND name, where possible.
Note that this is not really a great default name in the long run, since
this means that if there are multiple MTDs attached to the same
controller device, they will have the same name. But that is an existing
issue and requires future work on a better controller vs. flash chip
abstraction to fix properly.
Fixes: 853f1c58c4 ("mtd: nand: omap2: show parent device structure in sysfs")
Reported-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Heiko Schocher <hs@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Frans Klaver <fransklaver@gmail.com>
Cc: <stable@vger.kernel.org>
Now that the nand_chip struct directly embeds an mtd_info struct we can
get rid of the ->flash_node field and forward set/get_flash_node requests
to the MTD layer.
As a side effect, we no longer need the mtd_set_of_node() call done in
nand_dt_init().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
nand_dt_init() function requires 3 arguments where it actually needs one
(dn and mtd can both be retrieved from chip). Drop these parameters.
Testing for dn != NULL inside nand_dt_init() also helps simplifying the
caller code.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
mtd_to_nand() was recently introduced to avoid direct access to the
mtd->priv field. Update core code to use mtd_to_nand().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
If multiple NAND chips are registered to the same controller, then when
rebooting the system, the first one will grab the controller lock, while
the second will wait forever for the first one to release it. i.e., a
classic deadlock.
This problem was solved for a similar case (suspend/resume) back in
commit 6b0d9a8412 ("mtd: nand: fix multi-chip suspend problem"), and
the shutdown state really isn't much different for us, so rather than
adding a new special case to nand_get_device(), we can just overload the
FL_PM_SUSPENDED state.
Now, multiple chips can "get" the same controller lock (preventing
further I/O), while we still allow other chips to pass through
nand_shutdown().
Original report:
http://thread.gmane.org/gmane.linux.drivers.mtd/59726http://lists.infradead.org/pipermail/linux-mtd/2015-July/059992.html
Fixes: 72ea403669 ("mtd: nand: added nand_shutdown")
Reported-by: Andrew E. Mileski <andrewm@isoar.ca>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Andrew E. Mileski <andrewm@isoar.ca>
Acked-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
We should pass along our flash DT node to the MTD layer, so it can set
up ofpart for us.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
If nand_wait_ready() times out, this is silently ignored, and its
caller will then proceed to read from/write to the chip before it is
ready. This can potentially result in corruption with no indication as
to why.
While a 20ms timeout seems like it should be plenty enough, certain
behaviour can cause it to timeout much earlier than expected. The
situation which prompted this change was that CPU 0, which is
responsible for updating jiffies, was holding interrupts disabled
for a fairly long time while writing to the console during a printk,
causing several jiffies updates to be delayed. If CPU 1 happens to
enter the timeout loop in nand_wait_ready() just before CPU 0 re-
enables interrupts and updates jiffies, CPU 1 will immediately time
out when the delayed jiffies updates are made. The result of this is
that nand_wait_ready() actually waits less time than the NAND chip
would normally take to be ready, and then read_page() proceeds to
read out bad data from the chip.
The situation described above may seem unlikely, but in fact it can be
reproduced almost every boot on the MIPS Creator Ci20.
Therefore, this patch increases the timeout to 400ms. This should be
enough to cover cases where jiffies updates get delayed. In nand_wait()
the timeout was previously chosen based on whether erasing or
programming. This is changed to be 400ms unconditionally as well to
avoid similar problems there. nand_wait() is also slightly refactored
to be consistent with nand_wait{,_status}_ready(). These changes should
have no effect during normal operation.
Debugging this was made more difficult by the misleading comment above
nand_wait_ready() stating "The timeout is caught later" - no timeout was
ever reported, leading me away from the real source of the problem.
Therefore, a pr_warn() is added when a timeout does occur so that it is
easier to pinpoint similar problems in future.
Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Reviewed-by: Niklas Cassel <niklas.cassel@axis.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Brian 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: Boris 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: Brian Norris <computersforpeace@gmail.com>
The ->init_size() hook was introduced to let NAND controller drivers
support NAND devices that could not be described in the nand_ids table.
Since then, the core has added support for extended-id parsing and
full-id description, thus allowing to describe pretty much all existing
NANDs.
Moreover, this hook is not used by any mainline driver, and should not be
used by new drivers, because detecting the NAND chip is not something
controller specific.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Add two helper functions to help NAND controller drivers test whether a
specific NAND region is erased or not.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Use a more descriptive name for the device_node element in struct nand_chip .
This name matches the element name used for device_node property of a flash
in the spi-nor framework.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This is an example of why it doesn't make much sense to put this
information here in the first place. I don't really know what purpose it
serves.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
These are already-documented common bindings for NAND chips. Let's
handle them in nand_base.
If NAND controller drivers need to act on this data before bringing up
the NAND chip (e.g., fill out ECC callback functions, change HW modes,
etc.), then they can do so between calling nand_scan_ident() and
nand_scan_tail().
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
As all four bytes are written in any case the memset() is in vain.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
If a NAND device is not really present or pin muxes are not correctly
configured we can lock up the kernel waiting infinitely for NAND_STATUS
to be ready.
This can be easily reproduced on TI's DRA7-evm board by booting it
without NAND support in u-boot and disabling NAND pin muxes in the kernel.
Add timeout when waiting for NAND_CMD_RESET completion. As per ONFi v4.0
tRST can be upto 250ms for EZ-NAND and 5ms for raw NAND.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
We're not initializing the ooblen field. Our users don't care, since
they check that oobbuf == NULL first, but it's good practice to zero
unused fields out.
We can drop the NULL initializations since we're memset()ing the whole
thing.
Noticed by Coverity, CID #200821, #200822
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Coverity noticed that these 'ret' assignments weren't being used. Let's
use them.
Note that nand_lock() and nand_unlock() are still not officially used by
any drivers.
Coverity CIDs #1227054 and #1227037
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Previously, we requested that drivers pass ecc.size and ecc.bytes when
using NAND_ECC_SOFT_BCH. However, a driver is likely to only know the ECC
strength required for its NAND, so each driver would need to perform a
strength-to-bytes calculation.
Avoid duplicating this calculation in each driver by asking drivers to
pass ecc.size and ecc.strength so that the strength-to-bytes calculation
need only be implemented once.
This reverts/generalizes this commit:
mtd: nand: Base BCH ECC bytes on required strength
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
The MTD API reports -EUCLEAN only if the maximum number of bitflips
found in any ECC block exceeds a certain threshold. This is done to
avoid excessive -EUCLEAN reports to MTD users, which may induce
additional scrubbing of data, even when the ECC algorithm in use is
perfectly capable of handling the bitflips.
This threshold can be controlled by user-space (via sysfs), to allow
users to determine what they are willing to tolerate in their
application. But it still helps to have sane defaults.
In recent discussion [1], it was pointed out that our default threshold
is equal to the correction strength. That means that we won't actually
report any -EUCLEAN (i.e., "bitflips were corrected") errors until there
are almost too many to handle. It was determined that 3/4 of the
correction strength is probably a better default.
[1] http://lists.infradead.org/pipermail/linux-mtd/2015-January/057259.html
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Huang Shijie <shijie.huang@intel.com>
