mtd: nand: omap: ecc.calculate: merge omap3_calculate_ecc_bch8 in omap_calculate_ecc_bch

merge omap3_calculate_ecc_bch8() into omap_calculate_ecc_bch() so that
common callback can be used for both OMAP_ECC_BCH8_CODE_HW and
OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
+---------------------+-------------------------------------------------------+
|ecc-scheme           | nand_chip->calculate() after this patch               |
+---------------------+-------------------------------------------------------+
|HAM1_ECC             | omap_calculate_ecc()                                  |
+---------------------+-------------------------------------------------------+
|BCH4_HW_DETECTION_SW | omap_calculate_ecc_bch()                              |
|BCH4_HW              | omap_calculate_ecc_bch()                              |
|BCH8_HW_DETECTION_SW | omap3_calculate_ecc_bch8() -> omap_calculate_ecc_bch()|
|BCH8_HW              | omap_calculate_ecc_bch()                              |
+---------------------+-------------------------------------------------------+

Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 10 insertions, 49 deletions

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index e536267231e2..fa8143624384 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1122,54 +1122,8 @@ static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode)
 }
 #endif
 static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
-
-#ifdef CONFIG_MTD_NAND_ECC_BCH
-/**
- * omap3_calculate_ecc_bch8 - Generate 13 bytes of ECC bytes
- * @mtd: MTD device structure
- * @dat: The pointer to data on which ecc is computed
- * @ecc_code: The ecc_code buffer
- */
-static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
-                                    u_char *ecc_code)
-{
-        struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
-                                                   mtd);
-        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;
-}
-#endif /* CONFIG_MTD_NAND_ECC_BCH */
+static u8  bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
+                                0x97, 0x79, 0xe5, 0x24, 0xb5};
 
 /**
  * omap_calculate_ecc_bch - Generate bytes of ECC bytes
@@ -1194,6 +1148,7 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
         for (i = 0; i < nsectors; i++) {
                 ecc_code = ecc_calc;
                 switch (info->ecc_opt) {
+                case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
                 case OMAP_ECC_BCH8_CODE_HW:
                         bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
                         bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
@@ -1242,6 +1197,12 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
                         /* Set  8th ECC byte as 0x0 for ROM compatibility */
                         ecc_calc[eccbytes - 1] = 0x0;
                         break;
+                case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+                        /* Add constant polynomial to remainder, so that
+                         * ECC of blank pages results in 0x0 on reading back */
+                        for (i = 0; i < eccbytes; i++)
+                                ecc_calc[i] ^= bch8_polynomial[i];
+                        break;
                 case OMAP_ECC_BCH8_CODE_HW:
                         /* Set 14th ECC byte as 0x0 for ROM compatibility */
                         ecc_calc[eccbytes - 1] = 0x0;
@@ -1879,7 +1840,7 @@ static int omap_nand_probe(struct platform_device *pdev)
                 nand_chip->ecc.strength         = 8;
                 nand_chip->ecc.hwctl            = omap3_enable_hwecc_bch;
                 nand_chip->ecc.correct          = nand_bch_correct_data;
-                nand_chip->ecc.calculate        = omap3_calculate_ecc_bch8;
+                nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
                 /* define ECC layout */
                 ecclayout->eccbytes             = nand_chip->ecc.bytes *
                                                         (mtd->writesize /