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mtd: nand: omap: ecc.calculate: refactor omap_calculate_ecc_bch for BCHx_HW ecc-scheme

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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)      |
+------+------------------------------------+---------------+---------------+

This patch refactors omap_calculate_ecc_bch() so that
 - separate out ecc-scheme specific code so that common-code can be reused
   between different implementations of same ECC algorithm.
 - new ecc-schemes can be added with ease in future.

Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Pekon Gupta 2014-02-26 15:53:12 +05:30 committed by Brian Norris
parent a4c7ca004d
commit f5dc06fb71
1 changed files with 35 additions and 33 deletions
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68
drivers/mtd/nand/omap2.c
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@ -1219,33 +1219,25 @@ 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;
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 (info->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 +1251,10 @@ 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 +1263,26 @@ 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 (info->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;