mtd: nand: omap: ecc.calculate: merge omap3_calculate_ecc_bch4 in omap_calculate_ecc_bch

merges omap3_calculate_ecc_bch4() into omap_calculate_ecc_bch() so that
common callback can be used for both OMAP_ECC_BCH4_CODE_HW and
OMAP_ECC_BCH4_CODE_HW_DETECTION_SW ecc-schemes

+---------------------+-------------------------------------------------------+
|ecc-scheme           | nand_chip->calculate() after this patch               |
+---------------------+-------------------------------------------------------+
|HAM1_ECC             | omap_calculate_ecc()                                  |
+---------------------+-------------------------------------------------------+
|BCH4_HW_DETECTION_SW | omap3_calculate_ecc_bch4() -> omap_calculate_ecc_bch()|
|BCH4_HW              | omap_calculate_ecc_bch()                              |
|BCH8_HW_DETECTION_SW | omap3_calculate_ecc_bch8()                            |
|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, 41 deletions

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 2ccd557bf77d..e536267231e2 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1121,48 +1121,10 @@ static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode)
         writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
 }
 #endif
+static u8  bch4_polynomial[] = {0x28, 0x13, 0xcc, 0x39, 0x96, 0xac, 0x7f};
 
 #ifdef CONFIG_MTD_NAND_ECC_BCH
 /**
- * omap3_calculate_ecc_bch4 - Generate 7 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_bch4(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;
-        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]);
-
-                /*
-                 * Add constant polynomial to remainder, in order to get an ecc
-                 * sequence of 0xFFs for a buffer filled with 0xFFs; and
-                 * left-justify the resulting polynomial.
-                 */
-                *ecc_code++ = 0x28 ^ ((val2 >> 12) & 0xFF);
-                *ecc_code++ = 0x13 ^ ((val2 >>  4) & 0xFF);
-                *ecc_code++ = 0xcc ^ (((val2 & 0xF) << 4)|((val1 >> 28) & 0xF));
-                *ecc_code++ = 0x39 ^ ((val1 >> 20) & 0xFF);
-                *ecc_code++ = 0x96 ^ ((val1 >> 12) & 0xFF);
-                *ecc_code++ = 0xac ^ ((val1 >> 4) & 0xFF);
-                *ecc_code++ = 0x7f ^ ((val1 & 0xF) << 4);
-        }
-
-        return 0;
-}
-
-/**
  * omap3_calculate_ecc_bch8 - Generate 13 bytes of ECC bytes
  * @mtd: MTD device structure
  * @dat: The pointer to data on which ecc is computed
@@ -1209,7 +1171,6 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
 }
 #endif /* CONFIG_MTD_NAND_ECC_BCH */
 
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
 /**
  * omap_calculate_ecc_bch - Generate bytes of ECC bytes
  * @mtd:        MTD device structure
@@ -1252,6 +1213,7 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
                         *ecc_code++ = ((bch_val1 >> 8) & 0xFF);
                         *ecc_code++ = (bch_val1 & 0xFF);
                         break;
+                case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
                 case OMAP_ECC_BCH4_CODE_HW:
                         bch_val1 = readl(gpmc_regs->gpmc_bch_result0[i]);
                         bch_val2 = readl(gpmc_regs->gpmc_bch_result1[i]);
@@ -1270,6 +1232,12 @@ static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
 
                 /* ECC scheme specific syndrome customizations */
                 switch (info->ecc_opt) {
+                case OMAP_ECC_BCH4_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] ^= bch4_polynomial[i];
+                        break;
                 case OMAP_ECC_BCH4_CODE_HW:
                         /* Set  8th ECC byte as 0x0 for ROM compatibility */
                         ecc_calc[eccbytes - 1] = 0x0;
@@ -1327,6 +1295,7 @@ static int erased_sector_bitflips(u_char *data, u_char *oob,
         return flip_bits;
 }
 
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
 /**
  * omap_elm_correct_data - corrects page data area in case error reported
  * @mtd:        MTD device structure
@@ -1835,7 +1804,7 @@ static int omap_nand_probe(struct platform_device *pdev)
                 nand_chip->ecc.strength         = 4;
                 nand_chip->ecc.hwctl            = omap3_enable_hwecc_bch;
                 nand_chip->ecc.correct          = nand_bch_correct_data;
-                nand_chip->ecc.calculate        = omap3_calculate_ecc_bch4;
+                nand_chip->ecc.calculate        = omap_calculate_ecc_bch;
                 /* define ECC layout */
                 ecclayout->eccbytes             = nand_chip->ecc.bytes *
                                                         (mtd->writesize /