[PATCH v5 2/4] mtd: nand: omap: ecc.calculate: refactor omap_calculate_ecc_bch for BCHx_HW ecc-scheme
Pekon Gupta
pekon at ti.com
Tue Jan 7 08:45:44 EST 2014
OMAP NAND driver supports multiple flavours of BCH4 and BCH8 ECC algorithms.
+------+------------------------------------+---------------+---------------+
| Algo | ECC scheme |ECC calculation|Error detection|
+------+------------------------------------+---------------+---------------+
| |OMAP_ECC_BCH4_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W |
| BCH4 |OMAP_ECC_BCH4_CODE_HW |H/W (GPMC) |H/W (ELM) |
+------+------------------------------------+---------------+---------------+
| |OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W |
| BCH8 |OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) |
+------+------------------------------------+---------------+---------------+
As all implementations of H/W ecc-scheme use GPMC engine for ECC calculation,
Thus this patch:
(1) Replaces if..then..else with switch..case statements, so that code is
scalable for adding new ecc-schemes in future.
(2) Separates out ecc-scheme specific customizations into separate switch..case,
so that common code can be re-used between different flavours of ecc-scheme.
Signed-off-by: Pekon Gupta <pekon at ti.com>
---
drivers/mtd/nand/omap2.c | 69 +++++++++++++++++++++++++-----------------------
1 file changed, 36 insertions(+), 33 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index bf9bf7e..dabea92 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1219,33 +1219,26 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
* Support calculating of BCH4/8 ecc vectors for the page
*/
static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
- const u_char *dat, u_char *ecc_code)
+ const u_char *dat, u_char *ecc_calc)
{
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
+ int eccbytes = info->nand.ecc.bytes;
+ enum omap_ecc ecc_opt = info->ecc_opt;
+ struct gpmc_nand_regs *gpmc_regs = &info->reg;
+ u8 *ecc_code;
unsigned long nsectors, bch_val1, bch_val2, bch_val3, bch_val4;
- int i, eccbchtsel;
+ int i;
nsectors = ((readl(info->reg.gpmc_ecc_config) >> 4) & 0x7) + 1;
- /*
- * find BCH scheme used
- * 0 -> BCH4
- * 1 -> BCH8
- */
- eccbchtsel = ((readl(info->reg.gpmc_ecc_config) >> 12) & 0x3);
-
for (i = 0; i < nsectors; i++) {
-
- /* Read hw-computed remainder */
- bch_val1 = readl(info->reg.gpmc_bch_result0[i]);
- bch_val2 = readl(info->reg.gpmc_bch_result1[i]);
- if (eccbchtsel) {
- bch_val3 = readl(info->reg.gpmc_bch_result2[i]);
- bch_val4 = readl(info->reg.gpmc_bch_result3[i]);
- }
-
- if (eccbchtsel) {
- /* BCH8 ecc scheme */
+ ecc_code = ecc_calc;
+ switch (ecc_opt) {
+ case OMAP_ECC_BCH8_CODE_HW:
+ bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
+ bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
+ bch_val3 = readl(gpmc_regs->gpmc_bch_result2[i]);
+ bch_val4 = readl(gpmc_regs->gpmc_bch_result3[i]);
*ecc_code++ = (bch_val4 & 0xFF);
*ecc_code++ = ((bch_val3 >> 24) & 0xFF);
*ecc_code++ = ((bch_val3 >> 16) & 0xFF);
@@ -1259,14 +1252,10 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
*ecc_code++ = ((bch_val1 >> 16) & 0xFF);
*ecc_code++ = ((bch_val1 >> 8) & 0xFF);
*ecc_code++ = (bch_val1 & 0xFF);
- /*
- * Setting 14th byte to zero to handle
- * erased page & maintain compatibility
- * with RBL
- */
- *ecc_code++ = 0x0;
- } else {
- /* BCH4 ecc scheme */
+ break;
+ case OMAP_ECC_BCH4_CODE_HW:
+ bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
+ bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
*ecc_code++ = ((bch_val2 >> 12) & 0xFF);
*ecc_code++ = ((bch_val2 >> 4) & 0xFF);
*ecc_code++ = ((bch_val2 & 0xF) << 4) |
@@ -1275,12 +1264,26 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
*ecc_code++ = ((bch_val1 >> 12) & 0xFF);
*ecc_code++ = ((bch_val1 >> 4) & 0xFF);
*ecc_code++ = ((bch_val1 & 0xF) << 4);
- /*
- * Setting 8th byte to zero to handle
- * erased page
- */
- *ecc_code++ = 0x0;
+ break;
+ default:
+ return -EINVAL;
}
+
+ /* ECC scheme specific syndrome customizations */
+ switch (ecc_opt) {
+ case OMAP_ECC_BCH4_CODE_HW:
+ /* Set 8th ECC byte as 0x0 for ROM compatibility */
+ ecc_calc[eccbytes - 1] = 0x0;
+ break;
+ case OMAP_ECC_BCH8_CODE_HW:
+ /* Set 14th ECC byte as 0x0 for ROM compatibility */
+ ecc_calc[eccbytes - 1] = 0x0;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ecc_calc += eccbytes;
}
return 0;
--
1.8.1
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