mtd: nand: mxc: Fix failed/corrected values for v1 controllers

The v1 controller code has several flaws:
- We do not forward the number of corrected bitflips to the upper layers
- For 2k page NAND chips only the status results from the fourth subpage
  read are evaluated, so ECC failures in the other subpages remain
  uncovered
- When there are uncorrectable errors we have to increase the statistics
  counter, but still have to return successfully. Currently we return
  an error

This patch fixes this by introducing a v1 specific read_page function.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 4880432..49885af 100644 (file)
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -738,22 +738,65 @@ static void mxc_nand_enable_hwecc(struct mtd_info *mtd, int mode)
 static int mxc_nand_correct_data_v1(struct mtd_info *mtd, u_char *dat,
                                 u_char *read_ecc, u_char *calc_ecc)
 {
-       struct nand_chip *nand_chip = mtd_to_nand(mtd);
-       struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
+       return 0;
+}
 
-       /*
-        * 1-Bit errors are automatically corrected in HW.  No need for
-        * additional correction.  2-Bit errors cannot be corrected by
-        * HW ECC, so we need to return failure
-        */
-       uint16_t ecc_status = get_ecc_status_v1(host);
+static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
+                                bool ecc, int page)
+{
+       struct mtd_info *mtd = nand_to_mtd(chip);
+       struct mxc_nand_host *host = nand_get_controller_data(chip);
+       unsigned int bitflips_corrected = 0;
+       int no_subpages;
+       int i;
+
+       host->devtype_data->enable_hwecc(chip, ecc);
+
+       host->devtype_data->send_cmd(host, NAND_CMD_READ0, false);
+       mxc_do_addr_cycle(mtd, 0, page);
+
+       if (mtd->writesize > 512)
+               host->devtype_data->send_cmd(host, NAND_CMD_READSTART, true);
+
+       no_subpages = mtd->writesize >> 9;
+
+       for (i = 0; i < no_subpages; i++) {
+               uint16_t ecc_stats;
 
-       if (((ecc_status & 0x3) == 2) || ((ecc_status >> 2) == 2)) {
-               dev_dbg(host->dev, "HWECC uncorrectable 2-bit ECC error\n");
-               return -EBADMSG;
+               /* NANDFC buffer 0 is used for page read/write */
+               writew((host->active_cs << 4) | i, NFC_V1_V2_BUF_ADDR);
+
+               writew(NFC_OUTPUT, NFC_V1_V2_CONFIG2);
+
+               /* Wait for operation to complete */
+               wait_op_done(host, true);
+
+               ecc_stats = get_ecc_status_v1(host);
+
+               ecc_stats >>= 2;
+
+               if (buf && ecc) {
+                       switch (ecc_stats & 0x3) {
+                       case 0:
+                       default:
+                               break;
+                       case 1:
+                               mtd->ecc_stats.corrected++;
+                               bitflips_corrected = 1;
+                               break;
+                       case 2:
+                               mtd->ecc_stats.failed++;
+                               break;
+                       }
+               }
        }
 
-       return 0;
+       if (buf)
+               memcpy32_fromio(buf, host->main_area0, mtd->writesize);
+       if (oob)
+               copy_spare(mtd, true, oob);
+
+       return bitflips_corrected;
 }
 
 static int mxc_nand_correct_data_v2_v3(struct mtd_info *mtd, u_char *dat,
@@ -1494,6 +1537,7 @@ static struct nand_bbt_descr bbt_mirror_descr = {
 /* v1 + irqpending_quirk: i.MX21 */
 static const struct mxc_nand_devtype_data imx21_nand_devtype_data = {
        .preset = preset_v1,
+       .read_page = mxc_nand_read_page_v1,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v1,
@@ -1518,6 +1562,7 @@ static const struct mxc_nand_devtype_data imx21_nand_devtype_data = {
 /* v1 + !irqpending_quirk: i.MX27, i.MX31 */
 static const struct mxc_nand_devtype_data imx27_nand_devtype_data = {
        .preset = preset_v1,
+       .read_page = mxc_nand_read_page_v1,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v1,
@@ -1856,11 +1901,9 @@ static int mxcnd_probe(struct platform_device *pdev)
 
        switch (this->ecc.mode) {
        case NAND_ECC_HW:
-               if (host->devtype_data->read_page) {
-                       this->ecc.read_page = mxc_nand_read_page;
-                       this->ecc.read_page_raw = mxc_nand_read_page_raw;
-                       this->ecc.read_oob = mxc_nand_read_oob;
-               }
+               this->ecc.read_page = mxc_nand_read_page;
+               this->ecc.read_page_raw = mxc_nand_read_page_raw;
+               this->ecc.read_oob = mxc_nand_read_oob;
                this->ecc.calculate = mxc_nand_calculate_ecc;
                this->ecc.hwctl = mxc_nand_enable_hwecc;
                this->ecc.correct = host->devtype_data->correct_data;