[PATCH v2 12/14] mtd: nand: omap: handle gpmc bch[48]

Afzal Mohammed
2012-10-08T05:37:58Z

gpmc-nand bch registers are now available in driver,
make use of it to handle bch[48] instead of relying
on gpmc exported functions.

And so nand driver no longer needs gpmc header, remove it.

Signed-off-by: Afzal Mohammed <afzal@ti.com>
---
drivers/mtd/nand/omap2.c | 100 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 89 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index f0a1b1d..3282b15 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -28,7 +28,6 @@
#endif

#include <plat/dma.h>
-#include <plat/gpmc.h>
#include <linux/platform_data/mtd-nand-omap2.h>

#define DRIVER_NAME "omap2-nand"
@@ -106,6 +105,7 @@
#define CS_MASK 0x7
#define ENABLE_PREFETCH (0x1 << 7)
#define DMA_MPU_MODE_SHIFT 2
+#define ECCSIZE0_SHIFT 12
#define ECCSIZE1_SHIFT 22
#define ECC1RESULTSIZE 0x1
#define ECCCLEAR 0x100
@@ -1034,19 +1034,45 @@ static int omap_dev_ready(struct mtd_info *mtd)
static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode)
{
int nerrors;
- unsigned int dev_width;
+ unsigned int dev_width, nsectors;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
struct nand_chip *chip = mtd->priv;
+ u32 val;

nerrors = (info->nand.ecc.bytes == 13) ? 8 : 4;
dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
+ nsectors = 1;
/*
* Program GPMC to perform correction on one 512-byte sector at a time.
* Using 4 sectors at a time (i.e. ecc.size = 2048) is also possible and
* gives a slight (5%) performance gain (but requires additional code).
*/
- (void)gpmc_enable_hwecc_bch(info->gpmc_cs, mode, dev_width, 1, nerrors);
+
+ writel(ECC1, info->reg.gpmc_ecc_control);
+
+ /*
+ * When using BCH, sector size is hardcoded to 512 bytes.
+ * Here we are using wrapping mode 6 both for reading and writing, with:
+ * size0 = 0 (no additional protected byte in spare area)
+ * size1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
+ */
+ val = (32 << ECCSIZE1_SHIFT) | (0 << ECCSIZE0_SHIFT);
+ writel(val, info->reg.gpmc_ecc_size_config);
+
+ /* BCH configuration */
+ val = ((1 << 16) | /* enable BCH */
+ (((nerrors == 8) ? 1 : 0) << 12) | /* 8 or 4 bits */
+ (0x06 << 8) | /* wrap mode = 6 */
+ (dev_width << 7) | /* bus width */
+ (((nsectors-1) & 0x7) << 4) | /* number of sectors */
+ (info->gpmc_cs << 1) | /* ECC CS */
+ (0x1)); /* enable ECC */
+
+ writel(val, info->reg.gpmc_ecc_config);
+
+ /* clear ecc and enable bits */
+ writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
}

/**
@@ -1060,7 +1086,32 @@ static int omap3_calculate_ecc_bch4(struct mtd_info *mtd, const u_char *dat,
{
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
- return gpmc_calculate_ecc_bch4(info->gpmc_cs, dat, ecc_code);
+ unsigned long nsectors, val1, val2;
+ int i;
+
+ nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
+
+ for (i = 0; i < nsectors; i++) {
+
+ /* Read hw-computed remainder */
+ val1 = readl(info->reg.gpmc_bch_result0[i]);
+ val2 = readl(info->reg.gpmc_bch_result1[i]);
+
+ /*
+ * Add constant polynomial to remainder, in order to get an ecc
+ * sequence of 0xFFs for a buffer filled with 0xFFs; and
+ * left-justify the resulting polynomial.
+ */
+ *ecc_code++ = 0x28 ^ ((val2 >> 12) & 0xFF);
+ *ecc_code++ = 0x13 ^ ((val2 >> 4) & 0xFF);
+ *ecc_code++ = 0xcc ^ (((val2 & 0xF) << 4)|((val1 >> 28) & 0xF));
+ *ecc_code++ = 0x39 ^ ((val1 >> 20) & 0xFF);
+ *ecc_code++ = 0x96 ^ ((val1 >> 12) & 0xFF);
+ *ecc_code++ = 0xac ^ ((val1 >> 4) & 0xFF);
+ *ecc_code++ = 0x7f ^ ((val1 & 0xF) << 4);
+ }
+
+ return 0;
}

/**
@@ -1074,7 +1125,39 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
{
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
- return gpmc_calculate_ecc_bch8(info->gpmc_cs, dat, ecc_code);
+ unsigned long nsectors, val1, val2, val3, val4;
+ int i;
+
+ nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
+
+ for (i = 0; i < nsectors; i++) {
+
+ /* Read hw-computed remainder */
+ val1 = readl(info->reg.gpmc_bch_result0[i]);
+ val2 = readl(info->reg.gpmc_bch_result1[i]);
+ val3 = readl(info->reg.gpmc_bch_result2[i]);
+ val4 = readl(info->reg.gpmc_bch_result3[i]);
+
+ /*
+ * Add constant polynomial to remainder, in order to get an ecc
+ * sequence of 0xFFs for a buffer filled with 0xFFs.
+ */
+ *ecc_code++ = 0xef ^ (val4 & 0xFF);
+ *ecc_code++ = 0x51 ^ ((val3 >> 24) & 0xFF);
+ *ecc_code++ = 0x2e ^ ((val3 >> 16) & 0xFF);
+ *ecc_code++ = 0x09 ^ ((val3 >> 8) & 0xFF);
+ *ecc_code++ = 0xed ^ (val3 & 0xFF);
+ *ecc_code++ = 0x93 ^ ((val2 >> 24) & 0xFF);
+ *ecc_code++ = 0x9a ^ ((val2 >> 16) & 0xFF);
+ *ecc_code++ = 0xc2 ^ ((val2 >> 8) & 0xFF);
+ *ecc_code++ = 0x97 ^ (val2 & 0xFF);
+ *ecc_code++ = 0x79 ^ ((val1 >> 24) & 0xFF);
+ *ecc_code++ = 0xe5 ^ ((val1 >> 16) & 0xFF);
+ *ecc_code++ = 0x24 ^ ((val1 >> 8) & 0xFF);
+ *ecc_code++ = 0xb5 ^ (val1 & 0xFF);
+ }
+
+ return 0;
}

/**
@@ -1130,7 +1213,7 @@ static void omap3_free_bch(struct mtd_info *mtd)
*/
static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
{
- int ret, max_errors;
+ int max_errors;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
#ifdef CONFIG_MTD_NAND_OMAP_BCH8
@@ -1147,11 +1230,6 @@ static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
goto fail;
}

- /* initialize GPMC BCH engine */
- ret = gpmc_init_hwecc_bch(info->gpmc_cs, 1, max_errors);
- if (ret)
- goto fail;
-
/* software bch library is only used to detect and locate errors */
info->bch = init_bch(13, max_errors, 0x201b /* hw polynomial */);
if (!info->bch)
--
1.7.12