From: "Gupta, Pekon" <pekon@xxxxxx>
This patch adds following two flavours of BCH4 ECC scheme in omap2-nand driver
- OMAP_ECC_BCH4_CODE_HW_DETECTION_SW
- uses GPMC H/W engine for calculating ECC.
- uses software library (lib/bch.h & nand_bch.h) for error correction.
- OMAP_ECC_BCH4_CODE_HW
- uses GPMC H/W engine for calculating ECC.
- uses ELM H/W engine for error correction.
With this patch omap2-nand driver supports following ECC schemes:
+---------------------------------------+---------------+---------------+
| ECC scheme |ECC calculation|Error detection|
+---------------------------------------+---------------+---------------+
|OMAP_ECC_HAMMING_CODE_DEFAULT |S/W |S/W |
|OMAP_ECC_HAMMING_CODE_HW |H/W (GPMC) |S/W |
|OMAP_ECC_HAMMING_CODE_HW_ROMCODE |H/W (GPMC) |S/W |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH4_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.h)|
|OMAP_ECC_BCH4_CODE_HW |H/W (GPMC) |H/W (ELM) |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.h)|
|OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) |
+---------------------------------------+---------------+---------------+
Important:
- Selection of OMAP_ECC_BCHx_CODE_HW_DETECTION_SW requires,
Kconfig: CONFIG_MTD_NAND_ECC_BCH: enables S/W based BCH ECC algorithm.
- Selection of OMAP_ECC_BCHx_CODE_HW requires,
Kconfig: CONFIG_MTD_NAND_OMAP_BCH: enables ELM H/W module.
Signed-off-by: Gupta, Pekon <pekon@xxxxxx>
---
drivers/mtd/nand/Kconfig | 1 -
drivers/mtd/nand/omap2.c | 159 +++++++++++----------------
include/linux/platform_data/mtd-nand-omap2.h | 10 +-
3 files changed, 70 insertions(+), 100 deletions(-)
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 81bf5e5..b8196a1 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -112,7 +112,6 @@ config MTD_NAND_OMAP_BCH
bool "Enable support for hardware BCH error correction"
default n
select BCH
- select BCH_CONST_PARAMS
help
Support for hardware BCH error correction.
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 167f8d4..43e4dd4 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -27,6 +27,7 @@
#ifdef CONFIG_MTD_NAND_ECC_BCH
#include <linux/bch.h>
+#include <linux/mtd/nand_bch.h>
#endif
#ifdef CONFIG_MTD_NAND_OMAP_BCH
#include <linux/platform_data/elm.h>
@@ -185,10 +186,9 @@ struct omap_nand_info {
OMAP_NAND_IO_WRITE, /* write */
} iomode;
u_char *buf;
- int buf_len;
+ int buf_len;
struct gpmc_nand_regs reg;
/* fields specific for BCHx_HW ECC scheme */
- struct bch_control *bch;
bool is_elm_used;
struct device *elm_dev;
struct device_node *of_node;
@@ -1227,58 +1227,6 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
return 0;
}
-/**
- * omap3_correct_data_bch - Decode received data and correct errors
- * @mtd: MTD device structure
- * @data: page data
- * @read_ecc: ecc read from nand flash
- * @calc_ecc: ecc read from HW ECC registers
- */
-static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data,
- u_char *read_ecc, u_char *calc_ecc)
-{
- int i, count;
- /* cannot correct more than 8 errors */
- unsigned int errloc[8];
- struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
- mtd);
-
- count = decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL,
- errloc);
- if (count > 0) {
- /* correct errors */
- for (i = 0; i < count; i++) {
- /* correct data only, not ecc bytes */
- if (errloc[i] < 8*512)
- data[errloc[i]/8] ^= 1 << (errloc[i] & 7);
- pr_debug("corrected bitflip %u\n", errloc[i]);
- }
- } else if (count < 0) {
- pr_err("ecc unrecoverable error\n");
- }
- return count;
-}
-
-/**
- * omap3_free_bch - Release BCH ecc resources
- * @mtd: MTD device structure
- */
-static void omap3_free_bch(struct mtd_info *mtd)
-{
- struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
- mtd);
- if (info->bch) {
- free_bch(info->bch);
- info->bch = NULL;
- }
-}
-
-#else
-
-static void omap3_free_bch(struct mtd_info *mtd)
-{
-}
-
#endif /* CONFIG_MTD_NAND_ECC_BCH */
@@ -1735,6 +1683,7 @@ static int omap_nand_probe(struct platform_device *pdev)
#ifdef CONFIG_MTD_NAND_OMAP_BCH
info->of_node = pdata->of_node;
#endif
+ info->nand.ecc.priv = NULL;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
@@ -1882,27 +1831,36 @@ static int omap_nand_probe(struct platform_device *pdev)
info->nand.ecc.hwctl = omap_enable_hwecc;
info->nand.ecc.correct = omap_correct_data;
info->nand.ecc.mode = NAND_ECC_HW;
- info->bch = NULL;
break;
-
+#ifdef CONFIG_MTD_NAND_ECC_BCH
+ case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+ info->nand.ecc.mode = NAND_ECC_HW;
+ info->nand.ecc.size = 512;
+ info->nand.ecc.bytes = 7;
+ info->nand.ecc.strength = 4;
+ info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
+ info->nand.ecc.correct = nand_bch_correct_data;
+ info->nand.ecc.calculate = omap3_calculate_ecc_bch4;
+ break;
+#endif
#ifdef CONFIG_MTD_NAND_OMAP_BCH
- case OMAP_ECC_BCH8_CODE_HW:
+ case OMAP_ECC_BCH4_CODE_HW:
/* check if ELM module is present on SoC */
- if (is_elm_present(info, ECC_TYPE_BCH8) < 0) {
+ if (is_elm_present(info, ECC_TYPE_BCH4) < 0) {
pr_err("ELM module not detected, required for ECC\n");
err = -EINVAL;
goto out_release_mem_region;
}
info->nand.ecc.mode = NAND_ECC_HW;
info->nand.ecc.size = 512;
- info->nand.ecc.bytes = 14;
- info->nand.ecc.strength = 8;
+ /* 8th bit is kept reserved for ROM-code compatibility */
+ info->nand.ecc.bytes = 7 + 1;
+ info->nand.ecc.strength = 4;
info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
info->nand.ecc.correct = omap_elm_correct_data;
info->nand.ecc.calculate = omap3_calculate_ecc_bch;
info->nand.ecc.read_page = omap_read_page_bch;
info->nand.ecc.write_page = omap_write_page_bch;
- info->bch = NULL;
break;
#endif
#ifdef CONFIG_MTD_NAND_ECC_BCH
@@ -1912,36 +1870,28 @@ static int omap_nand_probe(struct platform_device *pdev)
info->nand.ecc.bytes = 13;
info->nand.ecc.strength = 8;
info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
- info->nand.ecc.correct = omap3_correct_data_bch;
+ info->nand.ecc.correct = nand_bch_correct_data;
info->nand.ecc.calculate = omap3_calculate_ecc_bch8;
- /* software bch library is used for locating errors */
- info->bch = init_bch(info->nand.ecc.bytes,
- info->nand.ecc.strength,
- OMAP_ECC_BCH8_POLYNOMIAL);
- if (!info->bch) {
- pr_err("unable initialize S/W BCH logic\n");
+ break;
+#endif
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
+ case OMAP_ECC_BCH8_CODE_HW:
+ /* check if ELM module is present on SoC */
+ if (is_elm_present(info, ECC_TYPE_BCH8) < 0) {
+ pr_err("ELM module not detected, required for ECC\n");
err = -EINVAL;
goto out_release_mem_region;
}
- break;
-
- case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
info->nand.ecc.mode = NAND_ECC_HW;
info->nand.ecc.size = 512;
- info->nand.ecc.bytes = 7;
- info->nand.ecc.strength = 4;
+ /* 14th bit is kept reserved for ROM-code compatibility */
+ info->nand.ecc.bytes = 13 + 1;
+ info->nand.ecc.strength = 8;
info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
- info->nand.ecc.correct = omap3_correct_data_bch;
- info->nand.ecc.calculate = omap3_calculate_ecc_bch4;
- /* software bch library is used for locating errors */
- info->bch = init_bch(info->nand.ecc.bytes,
- info->nand.ecc.strength,
- OMAP_ECC_BCH8_POLYNOMIAL);
- if (!info->bch) {
- pr_err("unable initialize S/W BCH logic\n");
- err = -EINVAL;
- goto out_release_mem_region;
- }
+ info->nand.ecc.correct = omap_elm_correct_data;
+ info->nand.ecc.calculate = omap3_calculate_ecc_bch;
+ info->nand.ecc.read_page = omap_read_page_bch;
+ info->nand.ecc.write_page = omap_write_page_bch;
break;
#endif
default:
@@ -1964,7 +1914,6 @@ static int omap_nand_probe(struct platform_device *pdev)
/* check if NAND OOBSIZE meets ECC scheme requirement */
omap_oobinfo.eccbytes = eccsteps * info->nand.ecc.bytes;
-
if (info->mtd.oobsize < (omap_oobinfo.eccbytes +
BADBLOCK_MARKER_LENGTH)) {
pr_err("not enough OOB bytes required = %d, available=%d",
@@ -1983,6 +1932,7 @@ static int omap_nand_probe(struct platform_device *pdev)
omap_oobinfo.oobfree->offset = offset + omap_oobinfo.eccbytes;
break;
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
case OMAP_ECC_BCH4_CODE_HW:
case OMAP_ECC_BCH8_CODE_HW:
/* check for small page devices */
@@ -1996,7 +1946,8 @@ static int omap_nand_probe(struct platform_device *pdev)
omap_oobinfo.oobfree->offset = BADBLOCK_MARKER_LENGTH +
omap_oobinfo.eccbytes;
break;
-
+#endif
+#ifdef CONFIG_MTD_NAND_ECC_BCH
case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
/* check for small page devices */
@@ -2005,16 +1956,26 @@ static int omap_nand_probe(struct platform_device *pdev)
err = -EINVAL;
goto out_release_mem_region;
}
- offset = info->mtd.oobsize - omap_oobinfo.eccbytes;
- omap_oobinfo.oobfree->offset = BADBLOCK_MARKER_LENGTH;
+ /* software bch library is used for locating errors */
+ info->nand.ecc.priv = nand_bch_init(&info->mtd,
+ info->nand.ecc.size,
+ info->nand.ecc.bytes,
+ &info->nand.ecc.layout);
+ if (!info->nand.ecc.priv) {
+ pr_err("unable initialize S/W BCH logic\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+ }
+ pr_info("using default ecc layout in nand_bch_init");
+ goto scan_tail;
break;
-
+#endif
default:
- pr_info("using default ecc layout for NAND device");
+ pr_info("using default ecc layout in generic driver");
goto scan_tail;
}
- /* populate other ecc_layout information based on ECC scheme */
+ /* populate other information for custom ecc layout */
if (!(info->nand.options & NAND_BUSWIDTH_16))
info->nand.badblock_pattern = &bb_descrip_flashbased;
@@ -2049,8 +2010,14 @@ out_release_mem_region:
if (info->gpmc_irq_fifo > 0)
free_irq(info->gpmc_irq_fifo, info);
release_mem_region(info->phys_base, info->mem_size);
+
out_free_info:
- omap3_free_bch(&info->mtd);
+#ifdef CONFIG_MTD_NAND_ECC_BCH
+ if (info->nand.ecc.priv) {
+ nand_bch_free(info->nand.ecc.priv);
+ info->nand.ecc.priv = NULL;
+ }
+#endif
kfree(info);
return err;
@@ -2062,8 +2029,12 @@ static int omap_nand_remove(struct platform_device *pdev)
struct mtd_info *mtd = platform_get_drvdata(pdev);
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
- omap3_free_bch(&info->mtd);
-
+#ifdef CONFIG_MTD_NAND_ECC_BCH
+ if (info->nand.ecc.priv) {
+ nand_bch_free(info->nand.ecc.priv);
+ info->nand.ecc.priv = NULL;
+ }
+#endif
platform_set_drvdata(pdev, NULL);
if (info->dma)
dma_release_channel(info->dma);
diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
index ce74576..9fcee61 100644
--- a/include/linux/platform_data/mtd-nand-omap2.h
+++ b/include/linux/platform_data/mtd-nand-omap2.h
@@ -30,14 +30,14 @@ enum omap_ecc {
/* 1-bit ECC calculation by GPMC, Error detection by Software */
/* ECC layout compatible to legacy ROMCODE. */
OMAP_ECC_HAMMING_CODE_HW_ROMCODE,
- /* 4-bit ECC calculation by GPMC, Error detection by ELM */
- OMAP_ECC_BCH4_CODE_HW,
/* 4-bit ECC calculation by GPMC, Error detection by Software */
OMAP_ECC_BCH4_CODE_HW_DETECTION_SW,
- /* 8-bit ECC calculation by GPMC, Error detection by ELM */
- OMAP_ECC_BCH8_CODE_HW,
+ /* 4-bit ECC calculation by GPMC, Error detection by ELM */
+ OMAP_ECC_BCH4_CODE_HW,
/* 8-bit ECC calculation by GPMC, Error detection by Software */
- OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
+ OMAP_ECC_BCH8_CODE_HW_DETECTION_SW,
+ /* 8-bit ECC calculation by GPMC, Error detection by ELM */
+ OMAP_ECC_BCH8_CODE_HW
};
struct gpmc_nand_regs {
--
1.8.1
--
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