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20d48595f8
linux/drivers/mtd/nand
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Masahiro Yamada 20d48595f8 mtd: nand: denali: fix bitflips calculation in handle_ecc() 
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: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
2017-04-25 14:18:33 +02:00
..
atmel mtd: nand: Cleanup/rework the atmel_nand driver 2017-04-25 14:18:29 +02:00
bcm47xxnflash mtd: nand: make use of nand_set/get_controller_data() helpers 2016-01-07 10:23:41 -08:00
brcmnand mtd: nand: brcmnand: return error code of nand_scan_ident/tail() on error 2016-11-07 14:48:47 +01:00
gpmi-nand sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
ams-delta.c mtd: nand: ams-delta: return error code of nand_scan() on error 2016-11-07 14:48:41 +01:00
au1550nd.c mtd: nand: au1550nd: set ECC algorithm explicitly 2016-05-05 23:51:53 +02:00
bf5xx_nand.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
cafe_nand.c mtd: nand: cafe: return error code of nand_scan_ident() on error 2016-11-07 14:48:51 +01:00
cmx270_nand.c mtd: nand: cmx270: return error code of nand_scan() on error 2016-11-07 14:48:41 +01:00
cs553x_nand.c mtd: nand: cs553x: return error code of nand_scan() on error 2016-11-07 14:48:42 +01:00
davinci_nand.c mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl 2016-09-09 19:39:33 -07:00
denali_dt.c mtd: nand: denali: introduce capability flag 2017-03-24 09:51:38 +01:00
denali_pci.c mtd: nand: denali: remove unneeded <linux/slab.h> includes 2016-11-19 09:30:55 +01:00
denali.c mtd: nand: denali: fix bitflips calculation in handle_ecc() 2017-04-25 14:18:33 +02:00
denali.h mtd: nand: denali: remove unnecessary writes to ECC_CORRECTION 2017-03-28 14:24:46 +02:00
diskonchip.c mtd: nand: diskonchip: switch to mtd_ooblayout_ops 2016-05-05 23:51:40 +02:00
docg4.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
fsl_elbc_nand.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
fsl_ifc_nand.c mtd: nand: ifc: Fix location of eccstat registers for IFC V1.0 2017-02-06 08:54:01 +01:00
fsl_upm.c mtd: nand: fsl_upm: set ECC algorithm explicitly 2016-05-05 23:51:54 +02:00
fsmc_nand.c mtd: nand: fsmc: remove CONFIG_OF conditional 2017-03-23 11:11:44 +01:00
gpio.c mtd: nand: gpio: make nCE GPIO optional 2017-03-16 10:34:27 +01:00
hisi504_nand.c mtd: nand: hisi504: return error code of nand_scan_ident() on error 2016-11-07 14:48:51 +01:00
jz4740_nand.c mtd: nand: jz4740: Remove unused local variable 2016-05-05 23:51:56 +02:00
jz4780_bch.c mtd: nand: jz4780: Update MODULE_AUTHOR email address 2016-07-11 08:40:19 +02:00
jz4780_bch.h mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs 2016-01-07 09:35:11 -08:00
jz4780_nand.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
Kconfig mtd: nand: Cleanup/rework the atmel_nand driver 2017-04-25 14:18:29 +02:00
lpc32xx_mlc.c mtd: nand: lpc32xx: fix invalid error handling of a requested irq 2017-01-04 20:50:18 +01:00
lpc32xx_slc.c mtd: nand: lpc32xx_slc: Remove unneeded NULL check on 'rc' 2017-01-30 11:50:30 +01:00
Makefile mtd: nand: Cleanup/rework the atmel_nand driver 2017-04-25 14:18:29 +02:00
mpc5121_nfc.c mtd: nand: mpc5121: return error code of nand_scan() on error 2016-11-07 14:48:43 +01:00
mtk_ecc.c mtd: mtk: avoid warning in mtk_ecc_encode 2016-10-28 10:21:23 +02:00
mtk_ecc.h mtd: mediatek: driver for MTK Smart Device 2016-07-11 08:39:54 +02:00
mtk_nand.c mtd: nand: mediatek: remove redundant dev_err call in mtk_nfc_probe() 2017-01-30 11:54:22 +01:00
mxc_nand.c mtd: nand: mxc: return error code of nand_scan_ident/tail() on error 2016-11-07 14:48:49 +01:00
nand_amd.c mtd: nand: Move AMD/Spansion specific init/detection logic in nand_amd.c 2017-03-08 23:21:22 +01:00
nand_base.c mtd: nand: relax ecc.read_page() return value for uncorrectable ECC 2017-04-25 14:18:31 +02:00
nand_bbt.c mtd: nand_bbt: scan for next free bbt block if writing bbt fails 2016-09-23 09:35:16 +02:00
nand_bch.c mtd: nand_bch: fix spelling of "probably" 2016-05-06 09:45:45 -07:00
nand_ecc.c mtd: nand: return consistent error codes in ecc.correct() implementations 2016-01-06 18:45:46 -08:00
nand_hynix.c mtd: nand: hynix: Fix an error code in init 2017-03-23 10:44:02 +01:00
nand_ids.c mtd: nand: Move Macronix specific initialization in nand_macronix.c 2017-03-08 23:21:23 +01:00
nand_macronix.c mtd: nand: Move Macronix specific initialization in nand_macronix.c 2017-03-08 23:21:23 +01:00
nand_micron.c mtd: nand: Move Micron specific init logic in nand_micron.c 2017-03-08 23:21:21 +01:00
nand_samsung.c mtd: nand: samsung: Retrieve ECC requirements from extended ID 2017-03-08 23:21:23 +01:00
nand_timings.c mtd: nand: Add a few more timings to nand_sdr_timings 2016-11-07 14:48:37 +01:00
nand_toshiba.c mtd: nand: Move Toshiba specific init/detection logic in nand_toshiba.c 2017-03-08 23:21:21 +01:00
nandsim.c mtd: nand: nandsim: fix spelling mistake: "weakpagess" -> "weakpages" 2017-03-16 10:23:38 +01:00
ndfc.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
nuc900_nand.c mtd: nand: nuc900: set ECC algorithm explicitly 2016-04-19 22:05:32 +02:00
omap2.c mtd: nand: omap2: return error code of nand_scan_ident/tail() on error 2016-11-07 14:48:50 +01:00
omap_elm.c mtd: omap_elm: print interrupt resource using %pr 2015-12-18 10:16:17 -08:00
orion_nand.c mtd: nand: orion: improve handling of optional clock 2017-03-29 17:05:37 +02:00
oxnas_nand.c mtd: nand: Add OX820 NAND Support 2016-10-22 14:24:21 +02:00
pasemi_nand.c mtd: nand: pasemi: return error code of nand_scan() on error 2016-11-07 14:48:45 +01:00
plat_nand.c mtd: nand: plat_nand: return error code of nand_scan() on error 2016-11-07 14:48:45 +01:00
pxa3xx_nand.c mtd: nand: pxa3xx: return error code of nand_scan_ident() on error 2016-11-07 14:48:52 +01:00
qcom_nandc.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
r852.c mtd: nand: make use of nand_set/get_controller_data() helpers 2016-01-07 10:23:41 -08:00
r852.h mtd: nand: r852: use the mtd instance embedded in struct nand_chip 2015-12-18 10:54:41 -08:00
s3c2410.c mtd: s3c2410: parse the device configuration from OF node 2016-11-07 14:48:36 +01:00
sh_flctl.c mtd: nand: sh_flctl: handle dma_submit() errors 2016-09-23 09:35:16 +02:00
sharpsl.c mtd: nand: sharpsl: switch to mtd_ooblayout_ops 2016-05-05 23:51:36 +02:00
sm_common.c mtd: nand: sm_common: switch to mtd_ooblayout_ops 2016-05-05 23:51:48 +02:00
sm_common.h mtd: use __packed shorthand 2014-08-19 11:53:08 -07:00
socrates_nand.c mtd: nand: socrates: use nand_scan() for nand_scan_ident/tail() combo 2016-11-07 14:48:53 +01:00
sunxi_nand.c mtd: nand: sunxi: simplify optional reset handling 2017-03-16 09:53:59 +01:00
tango_nand.c mtd: nand: tango: Enforce DMA direction type 2017-03-16 10:26:23 +01:00
tmio_nand.c mtd: nand: tmio: return error code of nand_scan() on error 2016-11-07 14:48:44 +01:00
txx9ndfmc.c mtd: nand: import nand_hw_control_init() 2016-09-23 09:35:16 +02:00
vf610_nfc.c mtd: nand: vf610: return error code of nand_scan_ident/tail() on error 2016-11-07 14:48:50 +01:00
xway_nand.c mtd: update my email address 2017-02-08 12:49:27 -08:00