The OMAP4 romcode expects some unusual ecc layout which we could
write but not read. This patch adds a function which uses the
manual mode to read a page written with this ecc layout.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/mtd/nand/nand_omap_gpmc.c | 99 ++++++++++++++++++++++++++++++++++---
1 files changed, 91 insertions(+), 8 deletions(-)
diff --git a/drivers/mtd/nand/nand_omap_gpmc.c b/drivers/mtd/nand/nand_omap_gpmc.c
index e6555bb..765a0d6 100644
--- a/drivers/mtd/nand/nand_omap_gpmc.c
+++ b/drivers/mtd/nand/nand_omap_gpmc.c
@@ -582,6 +582,96 @@ static void omap_enable_hwecc(struct mtd_info *mtd, int mode)
oinfo->gpmc_base + GPMC_ECC_CONTROL);
}
+static int omap_gpmc_read_buf_manual(struct mtd_info *mtd, struct nand_chip *chip,
+ void *buf, int bytes, int result_reg)
+{
+ struct gpmc_nand_info *oinfo = chip->priv;
+
+ writel(GPMC_ECC_SIZE_CONFIG_ECCSIZE1(0) |
+ GPMC_ECC_SIZE_CONFIG_ECCSIZE0(bytes * 2),
+ oinfo->gpmc_base + GPMC_ECC_SIZE_CONFIG);
+
+ writel(GPMC_ECC_CONTROL_ECCPOINTER(result_reg),
+ oinfo->gpmc_base + GPMC_ECC_CONTROL);
+
+ chip->read_buf(mtd, buf, bytes);
+
+ return bytes;
+}
+
+/*
+ * read a page with the ecc layout used by the OMAP4 romcode. The
+ * romcode expects an unusual ecc layout (f = free, e = ecc):
+ *
+ * 2f, 13e, 1f, 13e, 1f, 13e, 1f, 13e, 7f
+ *
+ * This can't be accomplished with the predefined ecc modes, so
+ * we have to use the manual mode here.
+ *
+ * For the manual mode we can't use the ECC_RESULTx_0 register set
+ * because it would disable ecc generation completeley. Also, the
+ * hardware seems to ignore eccsize1 (which should bypass ecc
+ * generation), so we use the otherwise unused ECC_RESULTx_5 to
+ * generate dummy eccs for the unprotected oob area.
+ */
+static int omap_gpmc_read_page_bch_rom_mode(struct mtd_info *mtd,
+ struct nand_chip *chip, uint8_t *buf)
+{
+ struct gpmc_nand_info *oinfo = chip->priv;
+ int dev_width = chip->options & NAND_BUSWIDTH_16 ? GPMC_ECC_CONFIG_ECC16B : 0;
+ uint8_t *p = buf;
+ uint8_t *ecc_calc = chip->buffers->ecccalc;
+ uint8_t *ecc_code = chip->buffers->ecccode;
+ uint32_t *eccpos = chip->ecc.layout->eccpos;
+ int stat, i;
+
+ writel(GPMC_ECC_SIZE_CONFIG_ECCSIZE1(0) |
+ GPMC_ECC_SIZE_CONFIG_ECCSIZE0(64),
+ oinfo->gpmc_base + GPMC_ECC_SIZE_CONFIG);
+
+ writel(GPMC_ECC_CONTROL_ECCPOINTER(1),
+ oinfo->gpmc_base + GPMC_ECC_CONTROL);
+
+ writel(GPMC_ECC_CONFIG_ECCALGORITHM |
+ GPMC_ECC_CONFIG_ECCBCHTSEL(1) |
+ GPMC_ECC_CONFIG_ECCWRAPMODE(0) |
+ dev_width | GPMC_ECC_CONFIG_ECCTOPSECTOR(3) |
+ GPMC_ECC_CONFIG_ECCCS(0) |
+ GPMC_ECC_CONFIG_ECCENABLE,
+ oinfo->gpmc_base + GPMC_ECC_CONFIG);
+
+ writel(GPMC_ECC_CONTROL_ECCCLEAR |
+ GPMC_ECC_CONTROL_ECCPOINTER(1),
+ oinfo->gpmc_base + GPMC_ECC_CONTROL);
+
+ for (i = 0; i < 32; i++)
+ p += omap_gpmc_read_buf_manual(mtd, chip, p, 64, (i >> 3) + 1);
+
+ p = chip->oob_poi;
+
+ p += omap_gpmc_read_buf_manual(mtd, chip, p, 2, 5);
+
+ for (i = 0; i < 4; i++) {
+ p += omap_gpmc_read_buf_manual(mtd, chip, p, 13, i + 1);
+ p += omap_gpmc_read_buf_manual(mtd, chip, p, 1, 5);
+ }
+
+ p += omap_gpmc_read_buf_manual(mtd, chip, p, 6, 5);
+
+ for (i = 0; i < chip->ecc.total; i++)
+ ecc_code[i] = chip->oob_poi[eccpos[i]];
+
+ __omap_calculate_ecc(mtd, buf, ecc_calc, 1);
+
+ stat = omap_correct_bch(mtd, buf, ecc_code, ecc_calc);
+ if (stat < 0)
+ mtd->ecc_stats.failed++;
+ else
+ mtd->ecc_stats.corrected += stat;
+
+ return 0;
+}
+
static int omap_gpmc_eccmode(struct gpmc_nand_info *oinfo,
enum gpmc_ecc_mode mode)
{
@@ -651,16 +741,9 @@ static int omap_gpmc_eccmode(struct gpmc_nand_info *oinfo,
omap_oobinfo.eccpos[i] = i + offset;
break;
case OMAP_ECC_BCH8_CODE_HW_ROMCODE:
- /*
- * Contradicting the datasheet the ecc checksum has to start
- * at byte 2 in oob. I have no idea how the rom code can
- * read this but it does.
- */
- dev_warn(oinfo->pdev, "using rom loader ecc mode. "
- "You can write properly but not read it back\n");
-
oinfo->nand.ecc.bytes = 4 * 13;
oinfo->nand.ecc.size = 4 * 512;
+ nand->ecc.read_page = omap_gpmc_read_page_bch_rom_mode;
omap_oobinfo.oobfree->length = 0;
j = 0;
for (i = 2; i < 15; i++)
--
1.7.7
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