[PATCH 3/5] mtd: nand: gpmi: correct bitflip for erased NAND page

Han Xu
2016-02-23T23:21:11Z

i.MX6QP and i.MX7D BCH module integrated a new feature to detect the
bitflip number for erased NAND page. So for these two platform, set the
erase threshold to ecc_strength and if bitflip detected, GPMI driver will
correct the data to all 0xFF.

Signed-off-by: Han Xu <han.xu@nxp.com>
---
drivers/mtd/nand/gpmi-nand/bch-regs.h | 10 ++++++++++
drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 5 +++++
drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 24 +++++++++++++++++++++++-
drivers/mtd/nand/gpmi-nand/gpmi-nand.h | 5 ++++-
4 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/gpmi-nand/bch-regs.h b/drivers/mtd/nand/gpmi-nand/bch-regs.h
index 53e58bc..a84d72b 100644
--- a/drivers/mtd/nand/gpmi-nand/bch-regs.h
+++ b/drivers/mtd/nand/gpmi-nand/bch-regs.h
@@ -30,7 +30,13 @@
#define BM_BCH_CTRL_COMPLETE_IRQ (1 << 0)

#define HW_BCH_STATUS0 0x00000010
+
#define HW_BCH_MODE 0x00000020
+#define BP_BCH_MODE_ERASE_THRESHOLD 0
+#define BM_BCH_MODE_ERASE_THRESHOLD (0xff << BP_BCH_MODE_ERASE_THRESHOLD)
+#define BF_BCH_MODE_ERASE_THRESHOLD(v) \
+ (((v) << BP_BCH_MODE_ERASE_THRESHOLD) & BM_BCH_MODE_ERASE_THRESHOLD)
+
#define HW_BCH_ENCODEPTR 0x00000030
#define HW_BCH_DATAPTR 0x00000040
#define HW_BCH_METAPTR 0x00000050
@@ -125,4 +131,8 @@
)

#define HW_BCH_VERSION 0x00000160
+#define HW_BCH_DEBUG1 0x00000170
+#define BP_BCH_DEBUG1_ERASED_ZERO_COUNT 0
+#define BM_BCH_DEBUG1_ERASED_ZERO_COUNT \
+ (0x1ff << BP_BCH_DEBUG1_ERASED_ZERO_COUNT)
#endif
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index 8acbe04..2c43213 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -298,6 +298,11 @@ int bch_set_geometry(struct gpmi_nand_data *this)
| BF_BCH_FLASH0LAYOUT1_DATAN_SIZE(block_size, this),
r->bch_regs + HW_BCH_FLASH0LAYOUT1);

+ /* Set erase threshold to ecc_strength for mx6qp and mx7 */
+ if (GPMI_IS_MX6QP(this) || GPMI_IS_MX7(this))
+ writel(BF_BCH_MODE_ERASE_THRESHOLD(ecc_strength),
+ r->bch_regs + HW_BCH_MODE);
+
/* Set *all* chip selects to use layout 0. */
writel(0, r->bch_regs + HW_BCH_LAYOUTSELECT);

diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
index 1aba6e6..6b3ca3b 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
@@ -71,6 +71,12 @@ static const struct gpmi_devdata gpmi_devdata_imx6q = {
.max_chain_delay = 12,
};

+static const struct gpmi_devdata gpmi_devdata_imx6qp = {
+ .type = IS_MX6QP,
+ .bch_max_ecc_strength = 40,
+ .max_chain_delay = 12,
+};
+
static const struct gpmi_devdata gpmi_devdata_imx6sx = {
.type = IS_MX6SX,
.bch_max_ecc_strength = 62,
@@ -1010,6 +1016,7 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
{
struct gpmi_nand_data *this = nand_get_controller_data(chip);
struct bch_geometry *nfc_geo = &this->bch_geometry;
+ void __iomem *bch_regs = this->resources.bch_regs;
void *payload_virt;
dma_addr_t payload_phys;
void *auxiliary_virt;
@@ -1018,6 +1025,7 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
unsigned char *status;
unsigned int max_bitflips = 0;
int ret;
+ int flag = 0;

dev_dbg(this->dev, "page number is : %d\n", page);
ret = read_page_prepare(this, buf, nfc_geo->payload_size,
@@ -1050,9 +1058,16 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
status = auxiliary_virt + nfc_geo->auxiliary_status_offset;

for (i = 0; i < nfc_geo->ecc_chunk_count; i++, status++) {
- if ((*status == STATUS_GOOD) || (*status == STATUS_ERASED))
+ if (*status == STATUS_GOOD)
continue;

+ if (*status == STATUS_ERASED) {
+ if (GPMI_IS_MX6QP(this) || GPMI_IS_MX7(this))
+ if (readl(bch_regs + HW_BCH_DEBUG1))
+ flag = 1;
+ continue;
+ }
+
if (*status == STATUS_UNCORRECTABLE) {
mtd->ecc_stats.failed++;
continue;
@@ -1081,6 +1096,10 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
nfc_geo->payload_size,
payload_virt, payload_phys);

+ /* if bitflip occurred in erased page, change data to all 0xff */
+ if (flag)
+ memset(buf, 0xff, nfc_geo->payload_size);
+
return max_bitflips;
}

@@ -1988,6 +2007,9 @@ static const struct of_device_id gpmi_nand_id_table[] = {
.compatible = "fsl,imx6q-gpmi-nand",
.data = &gpmi_devdata_imx6q,
}, {
+ .compatible = "fsl,imx6qp-gpmi-nand",
+ .data = (void *)&gpmi_devdata_imx6qp,
+ }, {
.compatible = "fsl,imx6sx-gpmi-nand",
.data = &gpmi_devdata_imx6sx,
}, {
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
index a82555f..605d96e 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
@@ -123,6 +123,7 @@ enum gpmi_type {
IS_MX23,
IS_MX28,
IS_MX6Q,
+ IS_MX6QP,
IS_MX6SX,
IS_MX7D,
};
@@ -305,9 +306,11 @@ void gpmi_copy_bits(u8 *dst, size_t dst_bit_off,
#define GPMI_IS_MX23(x) ((x)->devdata->type == IS_MX23)
#define GPMI_IS_MX28(x) ((x)->devdata->type == IS_MX28)
#define GPMI_IS_MX6Q(x) ((x)->devdata->type == IS_MX6Q)
+#define GPMI_IS_MX6QP(x) ((x)->devdata->type == IS_MX6QP)
#define GPMI_IS_MX6SX(x) ((x)->devdata->type == IS_MX6SX)
#define GPMI_IS_MX7D(x) ((x)->devdata->type == IS_MX7D)

-#define GPMI_IS_MX6(x) (GPMI_IS_MX6Q(x) || GPMI_IS_MX6SX(x))
+#define GPMI_IS_MX6(x) (GPMI_IS_MX6Q(x) || GPMI_IS_MX6QP(x)\
+ || GPMI_IS_MX6SX(x))
#define GPMI_IS_MX7(x) (GPMI_IS_MX7D(x))
#endif
--
1.9.1