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>

1 files changed, 15 insertions, 7 deletions

diff --git a/drivers/mtd/nand/tango_nand.c b/drivers/mtd/nand/tango_nand.c
index 82fea9b4c358..49b286c6c10f 100644
--- 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);