linux/drivers
Masahiro Yamada 57a4d8b5f6 mtd: nand: denali: support hardware-assisted erased page detection
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>
2017-06-20 09:14:48 +02:00
..
accessibility
acpi More ACPI updates for v4.12-rc1 2017-05-10 09:35:42 -07:00
amba
android
ata ARM: SoC driver updates 2017-05-09 10:01:15 -07:00
atm
auxdisplay
base More power management updates for v4.12-rc1 2017-05-10 09:12:30 -07:00
bcma
block virtio: fixes, cleanups, performance 2017-05-10 11:33:08 -07:00
bluetooth Bluetooth: hci_ldisc: Add protocol check to hci_uart_tx_wakeup() 2017-04-30 12:22:14 +02:00
bus
cdrom
char Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
clk Sort of on the quieter side this time, which is probably due more 2017-05-10 13:38:18 -07:00
clocksource Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-12 10:43:25 -07:00
connector
cpufreq Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-05-12 09:56:30 -07:00
cpuidle Merge branches 'pm-domains', 'pm-cpuidle', 'pm-sleep' and 'powercap' 2017-05-09 23:21:46 +02:00
crypto virtio: fixes, cleanups, performance 2017-05-10 11:33:08 -07:00
dax Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-05-12 15:43:10 -07:00
dca
devfreq
dio
dma dmaengine updates for 4.12-rc1 2017-05-09 15:40:28 -07:00
dma-buf
edac
eisa
extcon
firewire
firmware ARM: SoC driver updates 2017-05-09 10:01:15 -07:00
fmc
fpga
fsi
gpio Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
gpu drm/i915: Make vblank evade warnings optional 2017-05-12 14:28:02 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
hsi
hv char/misc patches for 4.12-rc1 2017-05-04 19:15:35 -07:00
hwmon hwmon: (twl4030-madc) drop driver 2017-04-30 11:45:31 -07:00
hwspinlock
hwtracing drivers/hwtracing/intel_th/msu.c: use set_memory.h header 2017-05-08 17:15:14 -07:00
i2c Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
ide ide: don't call memcpy with the same source and destination 2017-05-08 17:36:39 -04:00
idle x86/intel_idle: add Gemini Lake support 2017-05-01 23:17:37 +02:00
iio Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
infiniband Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-05-12 11:44:13 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2017-05-13 10:25:05 -07:00
iommu IOMMU Updates for Linux v4.12 2017-05-09 15:15:47 -07:00
ipack
irqchip Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-05-12 09:56:30 -07:00
isdn Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
leds scripts/spelling.txt: add "memory" pattern and fix typos 2017-05-08 17:15:13 -07:00
lguest
lightnvm lightnvm: fix bad back free on error path 2017-05-04 07:53:04 -06:00
macintosh DeviceTree for 4.12: 2017-05-05 19:33:07 -07:00
mailbox
mcb
md mm, vmalloc: use __GFP_HIGHMEM implicitly 2017-05-08 17:15:13 -07:00
media Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
memory MTD updates for 4.12-rc1: 2017-05-11 10:44:22 -07:00
memstick
message
mfd
misc Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
mmc Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
mtd mtd: nand: denali: support hardware-assisted erased page detection 2017-06-20 09:14:48 +02:00
net powerpc updates for 4.12 part 2 2017-05-12 10:04:09 -07:00
nfc
ntb
nubus
nvdimm Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-05-12 15:43:10 -07:00
nvme Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-05-11 11:01:56 -07:00
nvmem ARM: SoC driver updates 2017-05-09 10:01:15 -07:00
of powerpc updates for 4.12 part 2 2017-05-12 10:04:09 -07:00
oprofile
parisc
parport
pci Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
pcmcia Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
perf
phy
pinctrl Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
platform char/misc patches for 4.12-rc1 2017-05-04 19:15:35 -07:00
pnp
power power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
powercap powercap: intel_rapl: Add support for Gemini Lake 2017-04-28 23:56:16 +02:00
pps
ps3
ptp Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-01 16:15:18 -07:00
pwm Merge branch 'for-4.12/drivers' into for-next 2017-04-13 17:41:50 +02:00
rapidio char/misc patches for 4.12-rc1 2017-05-04 19:15:35 -07:00
ras
regulator Merge remote-tracking branch 'regulator/topic/vctrl' into regulator-next 2017-04-30 22:17:44 +09:00
remoteproc virtio: fixes, cleanups, performance 2017-05-10 11:33:08 -07:00
reset ARM: SoC driver updates 2017-05-09 10:01:15 -07:00
rpmsg virtio: fixes, cleanups, performance 2017-05-10 11:33:08 -07:00
rtc RTC for 4.12 2017-05-10 19:37:14 -07:00
s390 virtio: fixes, cleanups, performance 2017-05-10 11:33:08 -07:00
sbus
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-05-12 11:44:13 -07:00
sfi
sh
sn
soc powerpc updates for 4.12 part 2 2017-05-12 10:04:09 -07:00
spi
spmi
ssb
staging mtd: nand: Make sure drivers not supporting SET/GET_FEATURES return -ENOTSUPP 2017-05-30 08:59:26 +02:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-05-12 11:44:13 -07:00
tc
tee TEE driver infrastructure and OP-TEE drivers 2017-05-10 11:20:09 -07:00
thermal Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2017-05-12 11:58:45 -07:00
thunderbolt
tty Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
uio
usb DeviceTree for 4.12: 2017-05-05 19:33:07 -07:00
uwb
vfio powerpc updates for 4.12 part 1. 2017-05-05 11:36:44 -07:00
vhost mm: support __GFP_REPEAT in kvmalloc_node for >32kB 2017-05-08 17:15:12 -07:00
video fbdev changes for v4.12: 2017-05-11 11:12:26 -07:00
virt drivers/virt/fsl_hypervisor.c: use get_user_pages_unlocked() 2017-05-08 17:15:10 -07:00
virtio virtio: allow extra context per descriptor 2017-05-02 23:41:43 +03:00
vlynq
vme
w1
watchdog Annotation of module parameters that specify device settings 2017-05-10 19:13:03 -07:00
xen Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
zorro
Kconfig
Makefile TEE driver infrastructure and OP-TEE drivers 2017-05-10 11:20:09 -07:00