mtd: nand: tango: Update ecc_stats.corrected

According to Boris, some user-space tools expect MTD drivers to
update ecc_stats.corrected, and it's better to provide a lower
bound than to provide no information at all.

Fixes: 6956e2385a16 ("mtd: nand: add tango NAND flash controller support")
Cc: stable@vger.kernel.org
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/tango_nand.c b/drivers/mtd/nand/tango_nand.c
index 82fea9b..49b286c 100644 (file)
--- a/drivers/mtd/nand/tango_nand.c
+++ b/drivers/mtd/nand/tango_nand.c
@@ -55,10 +55,10 @@
  * byte 1 for other packets in the page (PKT_N, for N > 0)
  * ERR_COUNT_PKT_N is the max error count over all but the first packet.
  */
-#define DECODE_OK_PKT_0(v)     ((v) & BIT(7))
-#define DECODE_OK_PKT_N(v)     ((v) & BIT(15))
 #define ERR_COUNT_PKT_0(v)     (((v) >> 0) & 0x3f)
 #define ERR_COUNT_PKT_N(v)     (((v) >> 8) & 0x3f)
+#define DECODE_FAIL_PKT_0(v)   (((v) & BIT(7)) == 0)
+#define DECODE_FAIL_PKT_N(v)   (((v) & BIT(15)) == 0)
 
 /* Offsets relative to pbus_base */
 #define PBUS_CS_CTRL   0x83c
@@ -193,6 +193,8 @@ static int check_erased_page(struct nand_chip *chip, u8 *buf)
                                                  chip->ecc.strength);
                if (res < 0)
                        mtd->ecc_stats.failed++;
+               else
+                       mtd->ecc_stats.corrected += res;
 
                bitflips = max(res, bitflips);
                buf += pkt_size;
@@ -202,9 +204,11 @@ static int check_erased_page(struct nand_chip *chip, u8 *buf)
        return bitflips;
 }
 
-static int decode_error_report(struct tango_nfc *nfc)
+static int decode_error_report(struct nand_chip *chip)
 {
        u32 status, res;
+       struct mtd_info *mtd = nand_to_mtd(chip);
+       struct tango_nfc *nfc = to_tango_nfc(chip->controller);
 
        status = readl_relaxed(nfc->reg_base + NFC_XFER_STATUS);
        if (status & PAGE_IS_EMPTY)
@@ -212,10 +216,14 @@ static int decode_error_report(struct tango_nfc *nfc)
 
        res = readl_relaxed(nfc->mem_base + ERROR_REPORT);
 
-       if (DECODE_OK_PKT_0(res) && DECODE_OK_PKT_N(res))
-               return max(ERR_COUNT_PKT_0(res), ERR_COUNT_PKT_N(res));
+       if (DECODE_FAIL_PKT_0(res) || DECODE_FAIL_PKT_N(res))
+               return -EBADMSG;
+
+       /* ERR_COUNT_PKT_N is max, not sum, but that's all we have */
+       mtd->ecc_stats.corrected +=
+               ERR_COUNT_PKT_0(res) + ERR_COUNT_PKT_N(res);
 
-       return -EBADMSG;
+       return max(ERR_COUNT_PKT_0(res), ERR_COUNT_PKT_N(res));
 }
 
 static void tango_dma_callback(void *arg)
@@ -282,7 +290,7 @@ static int tango_read_page(struct mtd_info *mtd, struct nand_chip *chip,
        if (err)
                return err;
 
-       res = decode_error_report(nfc);
+       res = decode_error_report(chip);
        if (res < 0) {
                chip->ecc.read_oob_raw(mtd, chip, page);
                res = check_erased_page(chip, buf);