mtd: nand: mxc: Fix failed/corrected values for v2/v3 controllers

Currently nand_read_page_hwecc() from nand_base calls
mxc_nand_correct_data_v2_v3() for each subpage, but in this function we
return the corrected/failed results for the whole page instead
of a single subpage. On a 2k page size Nand this leads to results which
are 4 times too high.
The whole ecc.calculate/ecc.correct mechanism used by
nand_read_page_hwecc() is not suitable for devices which correct the
data in hardware, so fix this by using a driver specific read_page
function which does the right thing. Also add read_page_raw and read_oob
For proper raw and oob read support.

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 ab9cd45..4880432 100644 (file)
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -140,6 +140,8 @@ struct mxc_nand_host;
 
 struct mxc_nand_devtype_data {
        void (*preset)(struct mtd_info *);
+       int (*read_page)(struct nand_chip *chip, void *buf, void *oob, bool ecc,
+                        int page);
        void (*send_cmd)(struct mxc_nand_host *, uint16_t, int);
        void (*send_addr)(struct mxc_nand_host *, uint16_t, int);
        void (*send_page)(struct mtd_info *, unsigned int);
@@ -757,13 +759,35 @@ static int mxc_nand_correct_data_v1(struct mtd_info *mtd, u_char *dat,
 static int mxc_nand_correct_data_v2_v3(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;
+}
+
+static int mxc_nand_read_page_v2_v3(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 max_bitflips = 0;
        u32 ecc_stat, err;
-       int no_subpages = 1;
-       int ret = 0;
+       int no_subpages;
        u8 ecc_bit_mask, err_limit;
 
+       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);
+
+       host->devtype_data->send_page(mtd, NFC_OUTPUT);
+
+       if (buf)
+               memcpy32_fromio(buf, host->main_area0, mtd->writesize);
+       if (oob)
+               copy_spare(mtd, true, oob);
+
        ecc_bit_mask = (host->eccsize == 4) ? 0x7 : 0xf;
        err_limit = (host->eccsize == 4) ? 0x4 : 0x8;
 
@@ -774,17 +798,53 @@ static int mxc_nand_correct_data_v2_v3(struct mtd_info *mtd, u_char *dat,
        do {
                err = ecc_stat & ecc_bit_mask;
                if (err > err_limit) {
-                       dev_dbg(host->dev, "UnCorrectable RS-ECC Error\n");
-                       return -EBADMSG;
+                       mtd->ecc_stats.failed++;
                } else {
-                       ret += err;
+                       mtd->ecc_stats.corrected += err;
+                       max_bitflips = max_t(unsigned int, max_bitflips, err);
                }
+
                ecc_stat >>= 4;
        } while (--no_subpages);
 
-       dev_dbg(host->dev, "%d Symbol Correctable RS-ECC Error\n", ret);
+       return max_bitflips;
+}
 
-       return ret;
+static int mxc_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
+                             uint8_t *buf, int oob_required, int page)
+{
+       struct mxc_nand_host *host = nand_get_controller_data(chip);
+       void *oob_buf;
+
+       if (oob_required)
+               oob_buf = chip->oob_poi;
+       else
+               oob_buf = NULL;
+
+       return host->devtype_data->read_page(chip, buf, oob_buf, 1, page);
+}
+
+static int mxc_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
+                                 uint8_t *buf, int oob_required, int page)
+{
+       struct mxc_nand_host *host = nand_get_controller_data(chip);
+       void *oob_buf;
+
+       if (oob_required)
+               oob_buf = chip->oob_poi;
+       else
+               oob_buf = NULL;
+
+       return host->devtype_data->read_page(chip, buf, oob_buf, 0, page);
+}
+
+static int mxc_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+                            int page)
+{
+       struct mxc_nand_host *host = nand_get_controller_data(chip);
+
+       return host->devtype_data->read_page(chip, NULL, chip->oob_poi, 0,
+                                            page);
 }
 
 static int mxc_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
@@ -1483,6 +1543,7 @@ static const struct mxc_nand_devtype_data imx27_nand_devtype_data = {
 /* v21: i.MX25, i.MX35 */
 static const struct mxc_nand_devtype_data imx25_nand_devtype_data = {
        .preset = preset_v2,
+       .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v2,
@@ -1509,6 +1570,7 @@ static const struct mxc_nand_devtype_data imx25_nand_devtype_data = {
 /* v3.2a: i.MX51 */
 static const struct mxc_nand_devtype_data imx51_nand_devtype_data = {
        .preset = preset_v3,
+       .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v3,
        .send_addr = send_addr_v3,
        .send_page = send_page_v3,
@@ -1535,6 +1597,7 @@ static const struct mxc_nand_devtype_data imx51_nand_devtype_data = {
 /* v3.2b: i.MX53 */
 static const struct mxc_nand_devtype_data imx53_nand_devtype_data = {
        .preset = preset_v3,
+       .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v3,
        .send_addr = send_addr_v3,
        .send_page = send_page_v3,
@@ -1793,6 +1856,11 @@ 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.calculate = mxc_nand_calculate_ecc;
                this->ecc.hwctl = mxc_nand_enable_hwecc;
                this->ecc.correct = host->devtype_data->correct_data;