From: Bastian Hecht Date: Mon, 14 May 2012 12:14:46 +0000 (+0200) Subject: mtd: sh_flctl: Restructure the hardware ECC handling X-Git-Tag: upstream/snapshot3+hdmi~6490^2~159 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6667a6d58e25d351d8fce7a628a8c9c139a8bdc9;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git mtd: sh_flctl: Restructure the hardware ECC handling There are multiple reasons for a rewrite: - a race exists: when _4ECCEND is set, _4ECCFA may become true too meanwhile, which is lost and a non-correctable error is treated as correctable. - the ECC statistics don't get properly propagated to the base code. - empty pages would get marked as corrupted The rewrite resolves the issues and I hope it gives a more explicit code flow structure. Signed-off-by: Bastian Hecht Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c index 96e242ad..bc50e83 100644 --- a/drivers/mtd/nand/sh_flctl.c +++ b/drivers/mtd/nand/sh_flctl.c @@ -165,27 +165,56 @@ static void wait_wfifo_ready(struct sh_flctl *flctl) timeout_error(flctl, __func__); } -static int wait_recfifo_ready(struct sh_flctl *flctl, int sector_number) +static enum flctl_ecc_res_t wait_recfifo_ready + (struct sh_flctl *flctl, int sector_number) { uint32_t timeout = LOOP_TIMEOUT_MAX; - int checked[4]; void __iomem *ecc_reg[4]; int i; + int state = FL_SUCCESS; uint32_t data, size; - memset(checked, 0, sizeof(checked)); - + /* + * First this loops checks in FLDTCNTR if we are ready to read out the + * oob data. This is the case if either all went fine without errors or + * if the bottom part of the loop corrected the errors or marked them as + * uncorrectable and the controller is given time to push the data into + * the FIFO. + */ while (timeout--) { + /* check if all is ok and we can read out the OOB */ size = readl(FLDTCNTR(flctl)) >> 24; - if (size & 0xFF) - return 0; /* success */ + if ((size & 0xFF) == 4) + return state; + + /* check if a correction code has been calculated */ + if (!(readl(FL4ECCCR(flctl)) & _4ECCEND)) { + /* + * either we wait for the fifo to be filled or a + * correction pattern is being generated + */ + udelay(1); + continue; + } - if (readl(FL4ECCCR(flctl)) & _4ECCFA) - return 1; /* can't correct */ + /* check for an uncorrectable error */ + if (readl(FL4ECCCR(flctl)) & _4ECCFA) { + /* check if we face a non-empty page */ + for (i = 0; i < 512; i++) { + if (flctl->done_buff[i] != 0xff) { + state = FL_ERROR; /* can't correct */ + break; + } + } - udelay(1); - if (!(readl(FL4ECCCR(flctl)) & _4ECCEND)) + if (state == FL_SUCCESS) + dev_dbg(&flctl->pdev->dev, + "reading empty sector %d, ecc error ignored\n", + sector_number); + + writel(0, FL4ECCCR(flctl)); continue; + } /* start error correction */ ecc_reg[0] = FL4ECCRESULT0(flctl); @@ -194,28 +223,26 @@ static int wait_recfifo_ready(struct sh_flctl *flctl, int sector_number) ecc_reg[3] = FL4ECCRESULT3(flctl); for (i = 0; i < 3; i++) { + uint8_t org; + int index; + data = readl(ecc_reg[i]); - if (data != INIT_FL4ECCRESULT_VAL && !checked[i]) { - uint8_t org; - int index; - - if (flctl->page_size) - index = (512 * sector_number) + - (data >> 16); - else - index = data >> 16; - - org = flctl->done_buff[index]; - flctl->done_buff[index] = org ^ (data & 0xFF); - checked[i] = 1; - } - } + if (flctl->page_size) + index = (512 * sector_number) + + (data >> 16); + else + index = data >> 16; + + org = flctl->done_buff[index]; + flctl->done_buff[index] = org ^ (data & 0xFF); + } + state = FL_REPAIRABLE; writel(0, FL4ECCCR(flctl)); } timeout_error(flctl, __func__); - return 1; /* timeout */ + return FL_TIMEOUT; /* timeout */ } static void wait_wecfifo_ready(struct sh_flctl *flctl) @@ -259,20 +286,23 @@ static void read_fiforeg(struct sh_flctl *flctl, int rlen, int offset) } } -static int read_ecfiforeg(struct sh_flctl *flctl, uint8_t *buff, int sector) +static enum flctl_ecc_res_t read_ecfiforeg + (struct sh_flctl *flctl, uint8_t *buff, int sector) { int i; + enum flctl_ecc_res_t res; unsigned long *ecc_buf = (unsigned long *)buff; - void *fifo_addr = (void *)FLECFIFO(flctl); - for (i = 0; i < 4; i++) { - if (wait_recfifo_ready(flctl , sector)) - return 1; - ecc_buf[i] = readl(fifo_addr); - ecc_buf[i] = be32_to_cpu(ecc_buf[i]); + res = wait_recfifo_ready(flctl , sector); + + if (res != FL_ERROR) { + for (i = 0; i < 4; i++) { + ecc_buf[i] = readl(FLECFIFO(flctl)); + ecc_buf[i] = be32_to_cpu(ecc_buf[i]); + } } - return 0; + return res; } static void write_fiforeg(struct sh_flctl *flctl, int rlen, int offset) @@ -367,6 +397,7 @@ static void execmd_read_page_sector(struct mtd_info *mtd, int page_addr) { struct sh_flctl *flctl = mtd_to_flctl(mtd); int sector, page_sectors; + enum flctl_ecc_res_t ecc_result; page_sectors = flctl->page_size ? 4 : 1; @@ -382,17 +413,27 @@ static void execmd_read_page_sector(struct mtd_info *mtd, int page_addr) start_translation(flctl); for (sector = 0; sector < page_sectors; sector++) { - int ret; read_fiforeg(flctl, 512, 512 * sector); - ret = read_ecfiforeg(flctl, + ecc_result = read_ecfiforeg(flctl, &flctl->done_buff[mtd->writesize + 16 * sector], sector); - if (ret) - flctl->hwecc_cant_correct[sector] = 1; - - writel(0x0, FL4ECCCR(flctl)); + switch (ecc_result) { + case FL_REPAIRABLE: + dev_info(&flctl->pdev->dev, + "applied ecc on page 0x%x", page_addr); + flctl->mtd.ecc_stats.corrected++; + break; + case FL_ERROR: + dev_warn(&flctl->pdev->dev, + "page 0x%x contains corrupted data\n", + page_addr); + flctl->mtd.ecc_stats.failed++; + break; + default: + ; + } } wait_completion(flctl); diff --git a/include/linux/mtd/sh_flctl.h b/include/linux/mtd/sh_flctl.h index 3feaae0..01e4b15 100644 --- a/include/linux/mtd/sh_flctl.h +++ b/include/linux/mtd/sh_flctl.h @@ -129,9 +129,15 @@ #define _4ECCEND (0x1 << 1) /* 4 symbols end */ #define _4ECCEXST (0x1 << 0) /* 4 symbols exist */ -#define INIT_FL4ECCRESULT_VAL 0x03FF03FF #define LOOP_TIMEOUT_MAX 0x00010000 +enum flctl_ecc_res_t { + FL_SUCCESS, + FL_REPAIRABLE, + FL_ERROR, + FL_TIMEOUT +}; + struct sh_flctl { struct mtd_info mtd; struct nand_chip chip; @@ -151,8 +157,6 @@ struct sh_flctl { uint32_t flcmncr_base; /* base value of FLCMNCR */ uint32_t flintdmacr_base; /* irq enable bits */ - int hwecc_cant_correct[4]; - unsigned page_size:1; /* NAND page size (0 = 512, 1 = 2048) */ unsigned hwecc:1; /* Hardware ECC (0 = disabled, 1 = enabled) */ unsigned holden:1; /* Hardware has FLHOLDCR and HOLDEN is set */