ramips: correct page read return value of the mt7621 nand driver

read_page() need to return maximum number of bitflips instead of the
accumulated number. Change takes from upstream mt7621 u-boot [1].

 * @read_page:  function to read a page according to the ECC generator
 *              requirements; returns maximum number of bitflips
 *              corrected in any single ECC step, -EIO hw error

[1] https://lore.kernel.org/all/cover.1653015383.git.weijie.gao@mediatek.com/

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
(cherry picked from commit 2fbb91d73ffecc7d033e5bb0b550d664ef9e0f91)

diff --git a/target/linux/ramips/files/drivers/mtd/nand/raw/mt7621_nand.c b/target/linux/ramips/files/drivers/mtd/nand/raw/mt7621_nand.c
index f3a81ee4e24101f1b9769fee3ab22336b6e236cb..89cc7e2624af089bc76aad99bf2120377f1ff94e 100644 (file)
--- a/target/linux/ramips/files/drivers/mtd/nand/raw/mt7621_nand.c
+++ b/target/linux/ramips/files/drivers/mtd/nand/raw/mt7621_nand.c
@@ -1006,7 +1006,7 @@ static int mt7621_nfc_read_page_hwecc(struct nand_chip *nand, uint8_t *buf,
 {
        struct mt7621_nfc *nfc = nand_get_controller_data(nand);
        struct mtd_info *mtd = nand_to_mtd(nand);
-       int bitflips = 0;
+       int bitflips = 0, ret = 0;
        int rc, i;
 
        nand_read_page_op(nand, page, 0, NULL, 0);
@@ -1031,7 +1031,7 @@ static int mt7621_nfc_read_page_hwecc(struct nand_chip *nand, uint8_t *buf,
                mt7621_nfc_read_sector_fdm(nfc, i);
 
                if (rc < 0) {
-                       bitflips = -EIO;
+                       ret = -EIO;
                        continue;
                }
 
@@ -1043,10 +1043,11 @@ static int mt7621_nfc_read_page_hwecc(struct nand_chip *nand, uint8_t *buf,
                        dev_dbg(nfc->dev,
                                 "Uncorrectable ECC error at page %d.%d\n",
                                 page, i);
-                       bitflips = -EBADMSG;
+                       bitflips = nand->ecc.strength + 1;
                        mtd->ecc_stats.failed++;
-               } else if (bitflips >= 0) {
-                       bitflips += rc;
+               } else {
+                       if (rc > bitflips)
+                               bitflips = rc;
                        mtd->ecc_stats.corrected += rc;
                }
        }
@@ -1055,6 +1056,9 @@ static int mt7621_nfc_read_page_hwecc(struct nand_chip *nand, uint8_t *buf,
 
        nfi_write16(nfc, NFI_CON, 0);
 
+       if (ret < 0)
+               return ret;
+
        return bitflips;
 }