With increase in NAND flash densities occurence of bit-flips has increased.
Thus stronger ECC schemes are required for detecting and correcting multiple
simultaneous bit-flips in same NAND page. But stronger ECC schemes have large
ECC syndrome which require more space in OOB/Spare.
This patch add support for BCH16_ECC:
(a) BCH16_ECC can correct 16 bit-flips per 512Bytes of data.
(b) BCH16_ECC generates 26-bytes of ECC syndrome / 512B.
Due to (b) this scheme can only be used with NAND devices which have enough
OOB to satisfy following equation:
OOBsize per page >= 26 * (page-size / 512)
Signed-off-by: Pekon Gupta <pekon@xxxxxx>
---
arch/arm/mach-omap2/gpmc.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index e19de21..0d5639e 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -68,6 +68,9 @@
#define GPMC_ECC_BCH_RESULT_1 0x244 /* not available on OMAP2 */
#define GPMC_ECC_BCH_RESULT_2 0x248 /* not available on OMAP2 */
#define GPMC_ECC_BCH_RESULT_3 0x24c /* not available on OMAP2 */
+#define GPMC_ECC_BCH_RESULT_4 0x300 /* not available on OMAP2 */
+#define GPMC_ECC_BCH_RESULT_5 0x304 /* not available on OMAP2 */
+#define GPMC_ECC_BCH_RESULT_6 0x308 /* not available on OMAP2 */
/* GPMC ECC control settings */
#define GPMC_ECC_CTRL_ECCCLEAR 0x100
@@ -659,13 +662,19 @@ void gpmc_update_nand_reg(struct gpmc_nand_regs *reg, int cs)
for (i = 0; i < GPMC_BCH_NUM_REMAINDER; i++) {
reg->gpmc_bch_result0[i] = gpmc_base + GPMC_ECC_BCH_RESULT_0 +
- GPMC_BCH_SIZE * i;
+ (GPMC_BCH_SIZE * i);
reg->gpmc_bch_result1[i] = gpmc_base + GPMC_ECC_BCH_RESULT_1 +
- GPMC_BCH_SIZE * i;
+ (GPMC_BCH_SIZE * i);
reg->gpmc_bch_result2[i] = gpmc_base + GPMC_ECC_BCH_RESULT_2 +
- GPMC_BCH_SIZE * i;
+ (GPMC_BCH_SIZE * i);
reg->gpmc_bch_result3[i] = gpmc_base + GPMC_ECC_BCH_RESULT_3 +
- GPMC_BCH_SIZE * i;
+ (GPMC_BCH_SIZE * i);
+ reg->gpmc_bch_result4[i] = gpmc_base + GPMC_ECC_BCH_RESULT_4 +
+ (GPMC_BCH_SIZE * i);
+ reg->gpmc_bch_result5[i] = gpmc_base + GPMC_ECC_BCH_RESULT_5 +
+ (GPMC_BCH_SIZE * i);
+ reg->gpmc_bch_result6[i] = gpmc_base + GPMC_ECC_BCH_RESULT_6 +
+ (GPMC_BCH_SIZE * i);
}
}
@@ -1348,7 +1357,8 @@ static const char * const nand_ecc_opts[] = {
[OMAP_ECC_BCH4_CODE_HW] = "bch4_code_hw",
[OMAP_ECC_BCH4_CODE_HW_DETECTION_SW] = "bch4_code_hw_detection_sw",
[OMAP_ECC_BCH8_CODE_HW] = "bch8_code_hw",
- [OMAP_ECC_BCH8_CODE_HW_DETECTION_SW] = "bch8_code_hw_detection_sw"
+ [OMAP_ECC_BCH8_CODE_HW_DETECTION_SW] = "bch8_code_hw_detection_sw",
+ [OMAP_ECC_BCH16_CODE_HW] = "bch16_code_hw"
};
static const char * const nand_xfer_types[] = {
@@ -1389,7 +1399,7 @@ static int gpmc_probe_nand_child(struct platform_device *pdev,
if (!of_property_read_string(child, "ti,nand-xfer-type", &s))
for (val = 0; val < ARRAY_SIZE(nand_xfer_types); val++)
- if (!strcasecmp(s, nand_xfer_types[val])) {
+ if (!strcmp(s, nand_xfer_types[val])) {
gpmc_nand_data->xfer_type = val;
break;
}
--
1.8.1
--
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