Implant a missing ECC correction implementation and select_chip
implementation from Linux.

Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Kyungmin Park <kyungmin.p...@samsung.com>
Cc: Lukasz Majewski <l.majew...@samsung.com>
Cc: Minkyu Kang <mk7.k...@samsung.com>
Cc: Scott Wood <scottw...@freescale.com>
Cc: Vladimir Zapolskiy <v...@mleia.com>
---
 drivers/mtd/nand/s3c2410_nand.c | 89 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 84 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/s3c2410_nand.c b/drivers/mtd/nand/s3c2410_nand.c
index 91db6ca..f23a1c8 100644
--- a/drivers/mtd/nand/s3c2410_nand.c
+++ b/drivers/mtd/nand/s3c2410_nand.c
@@ -157,16 +157,93 @@ static int s3c24x0_nand_calculate_ecc(struct mtd_info 
*mtd, const u_char *dat,
 static int s3c24x0_nand_correct_data(struct mtd_info *mtd, u_char *dat,
                                     u_char *read_ecc, u_char *calc_ecc)
 {
-       if (read_ecc[0] == calc_ecc[0] &&
-           read_ecc[1] == calc_ecc[1] &&
-           read_ecc[2] == calc_ecc[2])
+       unsigned int diff0, diff1, diff2;
+       unsigned int bit, byte;
+
+       debug("%s(%p,%p,%p,%p)\n", __func__, mtd, dat, read_ecc, calc_ecc);
+
+       diff0 = read_ecc[0] ^ calc_ecc[0];
+       diff1 = read_ecc[1] ^ calc_ecc[1];
+       diff2 = read_ecc[2] ^ calc_ecc[2];
+
+       debug("%s: rd %*phN calc %*phN diff %02x%02x%02x\n",
+             __func__, 3, read_ecc, 3, calc_ecc,
+             diff0, diff1, diff2);
+
+       if (diff0 == 0 && diff1 == 0 && diff2 == 0)
+               return 0;               /* ECC is ok */
+
+       /* sometimes people do not think about using the ECC, so check
+        * to see if we have an 0xff,0xff,0xff read ECC and then ignore
+        * the error, on the assumption that this is an un-eccd page.
+        */
+       if (read_ecc[0] == 0xff && read_ecc[1] == 0xff && read_ecc[2] == 0xff
+           /*&& info->platform->ignore_unset_ecc*/)
                return 0;
 
-       printf("s3c24x0_nand_correct_data: not implemented\n");
+       /* Can we correct this ECC (ie, one row and column change).
+        * Note, this is similar to the 256 error code on smartmedia */
+
+       if (((diff0 ^ (diff0 >> 1)) & 0x55) == 0x55 &&
+           ((diff1 ^ (diff1 >> 1)) & 0x55) == 0x55 &&
+           ((diff2 ^ (diff2 >> 1)) & 0x55) == 0x55) {
+               /* calculate the bit position of the error */
+
+               bit  = ((diff2 >> 3) & 1) |
+                      ((diff2 >> 4) & 2) |
+                      ((diff2 >> 5) & 4);
+
+               /* calculate the byte position of the error */
+
+               byte = ((diff2 << 7) & 0x100) |
+                      ((diff1 << 0) & 0x80)  |
+                      ((diff1 << 1) & 0x40)  |
+                      ((diff1 << 2) & 0x20)  |
+                      ((diff1 << 3) & 0x10)  |
+                      ((diff0 >> 4) & 0x08)  |
+                      ((diff0 >> 3) & 0x04)  |
+                      ((diff0 >> 2) & 0x02)  |
+                      ((diff0 >> 1) & 0x01);
+
+               debug("correcting error bit %d, byte %d\n", bit, byte);
+
+               dat[byte] ^= (1 << bit);
+               return 1;
+       }
+
+       /* if there is only one bit difference in the ECC, then
+        * one of only a row or column parity has changed, which
+        * means the error is most probably in the ECC itself */
+
+       diff0 |= (diff1 << 8);
+       diff0 |= (diff2 << 16);
+
+       if ((diff0 & ~(1<<fls(diff0))) == 0)
+               return 1;
+
        return -1;
 }
 #endif
 
+static void s3c24x0_nand_select_chip(struct mtd_info *mtd, int chip)
+{
+       struct s3c24x0_nand *nand = s3c24x0_get_base_nand();
+       uint32_t sel_reg, sel_bit;
+
+#ifdef CONFIG_S3C2410
+       sel_reg = (uint32_t)&nand->nfconf;
+       sel_bit = S3C2410_NFCONF_nFCE;
+#else
+       sel_reg = (uint32_t)&nand->nfcont;
+       sel_bit = S3C2440_NFCONT_nFCE;
+#endif
+
+       if (chip == -1)
+               setbits_le32(sel_reg, sel_bit);
+       else
+               clrbits_le32(sel_reg, sel_bit);
+}
+
 int board_nand_init(struct nand_chip *nand)
 {
        uint32_t cfg = 0;
@@ -205,7 +282,7 @@ int board_nand_init(struct nand_chip *nand)
        nand->IO_ADDR_R = (void *)&nand_reg->nfdata;
        nand->IO_ADDR_W = (void *)&nand_reg->nfdata;
 
-       nand->select_chip = NULL;
+       nand->select_chip = s3c24x0_nand_select_chip;
 
        /* read_buf and write_buf are default */
        /* read_byte and write_byte are default */
@@ -221,6 +298,8 @@ int board_nand_init(struct nand_chip *nand)
 
        nand->dev_ready = s3c24x0_dev_ready;
 
+       nand->chip_delay = 50;
+
 #ifdef CONFIG_S3C2410_NAND_HWECC
        nand->ecc.hwctl = s3c24x0_nand_enable_hwecc;
        nand->ecc.calculate = s3c24x0_nand_calculate_ecc;
-- 
2.1.1

_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot

Reply via email to