[RESEND PATCH v3 2/5] mtd: nand: return consistent error codes in ecc.correct() implementations
Brian Norris
computersforpeace at gmail.com
Mon Sep 21 16:10:29 PDT 2015
+ a few others for review/test, since this touches several drivers
On Thu, Sep 03, 2015 at 06:03:39PM +0200, Boris Brezillon wrote:
> The error code returned by the ecc.correct() are not consistent over the
> all implementations.
>
> Document the expected behavior in include/linux/mtd/nand.h and fix
> offending implementations.
>
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
The patch all looks good to me. A note below:
> ---
> drivers/mtd/nand/atmel_nand.c | 2 +-
> drivers/mtd/nand/bf5xx_nand.c | 20 ++++++++++++++------
> drivers/mtd/nand/davinci_nand.c | 6 +++---
> drivers/mtd/nand/jz4740_nand.c | 4 ++--
> drivers/mtd/nand/mxc_nand.c | 4 ++--
> drivers/mtd/nand/nand_bch.c | 2 +-
> drivers/mtd/nand/nand_ecc.c | 2 +-
> drivers/mtd/nand/omap2.c | 6 +++---
> drivers/mtd/nand/r852.c | 4 ++--
> include/linux/mtd/nand.h | 8 +++++++-
> include/linux/mtd/nand_bch.h | 2 +-
> 11 files changed, 37 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index 46010bd..dc7b399 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -1443,7 +1443,7 @@ static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
> * We can't correct so many errors */
> dev_dbg(host->dev, "atmel_nand : multiple errors detected."
> " Unable to correct.\n");
> - return -EIO;
> + return -EBADMSG;
> }
>
> /* if there's a single bit error : we can correct it */
> diff --git a/drivers/mtd/nand/bf5xx_nand.c b/drivers/mtd/nand/bf5xx_nand.c
> index 4d8d4ba..9c39056 100644
> --- a/drivers/mtd/nand/bf5xx_nand.c
> +++ b/drivers/mtd/nand/bf5xx_nand.c
> @@ -252,7 +252,7 @@ static int bf5xx_nand_correct_data_256(struct mtd_info *mtd, u_char *dat,
> */
> if (hweight32(syndrome[0]) == 1) {
> dev_err(info->device, "ECC data was incorrect!\n");
> - return 1;
> + return -EBADMSG;
> }
>
> syndrome[1] = (calced & 0x7FF) ^ (stored & 0x7FF);
> @@ -285,7 +285,7 @@ static int bf5xx_nand_correct_data_256(struct mtd_info *mtd, u_char *dat,
> data = data ^ (0x1 << failing_bit);
> *(dat + failing_byte) = data;
>
> - return 0;
> + return 1;
> }
>
> /*
> @@ -298,26 +298,34 @@ static int bf5xx_nand_correct_data_256(struct mtd_info *mtd, u_char *dat,
> dev_err(info->device,
> "Please discard data, mark bad block\n");
>
> - return 1;
> + return -EBADMSG;
> }
The above changes to bf5xx_nand all look correct, but they are actually
semantic changes that could be considered a bugfix (correctable errors
were going unreported, and uncorrectable errors were being reported as
correctable). I'm not sure this really deserves special treatment (e.g.,
-stable) since apparently no one cared. Perhaps this platform is dead?
Anyway, I'll probably add a comment to the commit description if I take
this patch.
No other comment, but context left intact below.
Brian
>
> static int bf5xx_nand_correct_data(struct mtd_info *mtd, u_char *dat,
> u_char *read_ecc, u_char *calc_ecc)
> {
> struct nand_chip *chip = mtd->priv;
> - int ret;
> + int ret, bitflips = 0;
>
> ret = bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc);
> + if (ret < 0)
> + return ret;
> +
> + bitflips = ret;
>
> /* If ecc size is 512, correct second 256 bytes */
> if (chip->ecc.size == 512) {
> dat += 256;
> read_ecc += 3;
> calc_ecc += 3;
> - ret |= bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc);
> + ret = bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc);
> + if (ret < 0)
> + return ret;
> +
> + bitflips += ret;
> }
>
> - return ret;
> + return bitflips;
> }
>
> static void bf5xx_nand_enable_hwecc(struct mtd_info *mtd, int mode)
> diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
> index b9080130..816ef53 100644
> --- a/drivers/mtd/nand/davinci_nand.c
> +++ b/drivers/mtd/nand/davinci_nand.c
> @@ -206,7 +206,7 @@ static int nand_davinci_correct_1bit(struct mtd_info *mtd, u_char *dat,
> dat[diff >> (12 + 3)] ^= BIT((diff >> 12) & 7);
> return 1;
> } else {
> - return -1;
> + return -EBADMSG;
> }
> } else if (!(diff & (diff - 1))) {
> /* Single bit ECC error in the ECC itself,
> @@ -214,7 +214,7 @@ static int nand_davinci_correct_1bit(struct mtd_info *mtd, u_char *dat,
> return 1;
> } else {
> /* Uncorrectable error */
> - return -1;
> + return -EBADMSG;
> }
>
> }
> @@ -390,7 +390,7 @@ compare:
> return 0;
> case 1: /* five or more errors detected */
> davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
> - return -EIO;
> + return -EBADMSG;
> case 2: /* error addresses computed */
> case 3:
> num_errors = 1 + ((fsr >> 16) & 0x03);
> diff --git a/drivers/mtd/nand/jz4740_nand.c b/drivers/mtd/nand/jz4740_nand.c
> index ebf2cce..ba44af3 100644
> --- a/drivers/mtd/nand/jz4740_nand.c
> +++ b/drivers/mtd/nand/jz4740_nand.c
> @@ -254,7 +254,7 @@ static int jz_nand_correct_ecc_rs(struct mtd_info *mtd, uint8_t *dat,
> } while (!(status & JZ_NAND_STATUS_DEC_FINISH) && --timeout);
>
> if (timeout == 0)
> - return -1;
> + return -ETIMEDOUT;
>
> reg = readl(nand->base + JZ_REG_NAND_ECC_CTRL);
> reg &= ~JZ_NAND_ECC_CTRL_ENABLE;
> @@ -262,7 +262,7 @@ static int jz_nand_correct_ecc_rs(struct mtd_info *mtd, uint8_t *dat,
>
> if (status & JZ_NAND_STATUS_ERROR) {
> if (status & JZ_NAND_STATUS_UNCOR_ERROR)
> - return -1;
> + return -EBADMSG;
>
> error_count = (status & JZ_NAND_STATUS_ERR_COUNT) >> 29;
>
> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> index 2426db8..7710fff 100644
> --- a/drivers/mtd/nand/mxc_nand.c
> +++ b/drivers/mtd/nand/mxc_nand.c
> @@ -675,7 +675,7 @@ static int mxc_nand_correct_data_v1(struct mtd_info *mtd, u_char *dat,
>
> if (((ecc_status & 0x3) == 2) || ((ecc_status >> 2) == 2)) {
> pr_debug("MXC_NAND: HWECC uncorrectable 2-bit ECC error\n");
> - return -1;
> + return -EBADMSG;
> }
>
> return 0;
> @@ -702,7 +702,7 @@ static int mxc_nand_correct_data_v2_v3(struct mtd_info *mtd, u_char *dat,
> err = ecc_stat & ecc_bit_mask;
> if (err > err_limit) {
> printk(KERN_WARNING "UnCorrectable RS-ECC Error\n");
> - return -1;
> + return -EBADMSG;
> } else {
> ret += err;
> }
> diff --git a/drivers/mtd/nand/nand_bch.c b/drivers/mtd/nand/nand_bch.c
> index 3803e0b..6cbf305 100644
> --- a/drivers/mtd/nand/nand_bch.c
> +++ b/drivers/mtd/nand/nand_bch.c
> @@ -98,7 +98,7 @@ int nand_bch_correct_data(struct mtd_info *mtd, unsigned char *buf,
> }
> } else if (count < 0) {
> printk(KERN_ERR "ecc unrecoverable error\n");
> - count = -1;
> + count = -EBADMSG;
> }
> return count;
> }
> diff --git a/drivers/mtd/nand/nand_ecc.c b/drivers/mtd/nand/nand_ecc.c
> index 97c4c02..244a634 100644
> --- a/drivers/mtd/nand/nand_ecc.c
> +++ b/drivers/mtd/nand/nand_ecc.c
> @@ -507,7 +507,7 @@ int __nand_correct_data(unsigned char *buf,
> return 1; /* error in ECC data; no action needed */
>
> pr_err("%s: uncorrectable ECC error\n", __func__);
> - return -1;
> + return -EBADMSG;
> }
> EXPORT_SYMBOL(__nand_correct_data);
>
> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
> index 60fa899..03e2faa 100644
> --- a/drivers/mtd/nand/omap2.c
> +++ b/drivers/mtd/nand/omap2.c
> @@ -830,12 +830,12 @@ static int omap_compare_ecc(u8 *ecc_data1, /* read from NAND memory */
> case 1:
> /* Uncorrectable error */
> pr_debug("ECC UNCORRECTED_ERROR 1\n");
> - return -1;
> + return -EBADMSG;
>
> case 11:
> /* UN-Correctable error */
> pr_debug("ECC UNCORRECTED_ERROR B\n");
> - return -1;
> + return -EBADMSG;
>
> case 12:
> /* Correctable error */
> @@ -865,7 +865,7 @@ static int omap_compare_ecc(u8 *ecc_data1, /* read from NAND memory */
> return 0;
> }
> pr_debug("UNCORRECTED_ERROR default\n");
> - return -1;
> + return -EBADMSG;
> }
> }
>
> diff --git a/drivers/mtd/nand/r852.c b/drivers/mtd/nand/r852.c
> index cc6bac5..c9ad7a0 100644
> --- a/drivers/mtd/nand/r852.c
> +++ b/drivers/mtd/nand/r852.c
> @@ -477,7 +477,7 @@ static int r852_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
>
> if (dev->dma_error) {
> dev->dma_error = 0;
> - return -1;
> + return -EIO;
> }
>
> r852_write_reg(dev, R852_CTL, dev->ctlreg | R852_CTL_ECC_ACCESS);
> @@ -491,7 +491,7 @@ static int r852_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
> /* ecc uncorrectable error */
> if (ecc_status & R852_ECC_FAIL) {
> dbg("ecc: unrecoverable error, in half %d", i);
> - error = -1;
> + error = -EBADMSG;
> goto exit;
> }
>
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 77affe9..19d43b1 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -456,7 +456,13 @@ struct nand_hw_control {
> * @hwctl: function to control hardware ECC generator. Must only
> * be provided if an hardware ECC is available
> * @calculate: function for ECC calculation or readback from ECC hardware
> - * @correct: function for ECC correction, matching to ECC generator (sw/hw)
> + * @correct: function for ECC correction, matching to ECC generator (sw/hw).
> + * Should return a positive number representing the number of
> + * corrected bitflips, -EBADMSG if the number of bitflips exceed
> + * ECC strength, or any other error code if the error is not
> + * directly related to correction.
> + * If -EBADMSG is returned the input buffers should be left
> + * untouched.
> * @read_page_raw: function to read a raw page without ECC. This function
> * should hide the specific layout used by the ECC
> * controller and always return contiguous in-band and
> diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h
> index 74acf53..fb0bc34 100644
> --- a/include/linux/mtd/nand_bch.h
> +++ b/include/linux/mtd/nand_bch.h
> @@ -55,7 +55,7 @@ static inline int
> nand_bch_correct_data(struct mtd_info *mtd, unsigned char *buf,
> unsigned char *read_ecc, unsigned char *calc_ecc)
> {
> - return -1;
> + return -ENOTSUPP;
> }
>
> static inline struct nand_bch_control *
> --
> 1.9.1
>
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