mtd: spinand: Introduce a way to avoid raw access

SkyHigh spinand device has ECC enable bit in configuration register but
it must be always enabled. If ECC is disabled, read and write ops
results in undetermined state. For such devices, a way to avoid raw
access is needed.

Introduce SPINAND_NO_RAW_ACCESS flag to advertise the device does not
support raw access. In such devices, the on-die ECC engine ops returns
error to I/O request in raw mode.

Checking and marking BBM need to be cared as special case, by adding
fallback mechanism that tries read/write OOB with ECC enabled.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 00e1bfa416ceb46ca792377d93920e905c22939c..f46769eda388ec30839ef86cf0eb5097cf030cde 100644 (file)
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -294,6 +294,9 @@ static int spinand_ondie_ecc_prepare_io_req(struct nand_device *nand,
        struct spinand_device *spinand = nand_to_spinand(nand);
        bool enable = (req->mode != MTD_OPS_RAW);
 
+       if (!enable && spinand->flags & SPINAND_NO_RAW_ACCESS)
+               return -EOPNOTSUPP;
+
        memset(spinand->oobbuf, 0xff, nanddev_per_page_oobsize(nand));
 
        /* Only enable or disable the engine */
@@ -901,9 +904,17 @@ static bool spinand_isbad(struct nand_device *nand, const struct nand_pos *pos)
                .oobbuf.in = marker,
                .mode = MTD_OPS_RAW,
        };
+       int ret;
 
        spinand_select_target(spinand, pos->target);
-       spinand_read_page(spinand, &req);
+
+       ret = spinand_read_page(spinand, &req);
+       if (ret == -EOPNOTSUPP) {
+               /* Retry with ECC in case raw access is not supported */
+               req.mode = MTD_OPS_PLACE_OOB;
+               spinand_read_page(spinand, &req);
+       }
+
        if (marker[0] != 0xff || marker[1] != 0xff)
                return true;
 
@@ -942,7 +953,14 @@ static int spinand_markbad(struct nand_device *nand, const struct nand_pos *pos)
        if (ret)
                return ret;
 
-       return spinand_write_page(spinand, &req);
+       ret = spinand_write_page(spinand, &req);
+       if (ret == -EOPNOTSUPP) {
+               /* Retry with ECC in case raw access is not supported */
+               req.mode = MTD_OPS_PLACE_OOB;
+               ret = spinand_write_page(spinand, &req);
+       }
+
+       return ret;
 }
 
 static int spinand_mtd_block_markbad(struct mtd_info *mtd, loff_t offs)

diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index 702e5fb13dae73de5e77ddc71964dd46ff756253..5cf11005b41ae2ca78eccb35ddf81a21823953ba 100644 (file)
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -314,6 +314,7 @@ struct spinand_ecc_info {
 #define SPINAND_HAS_CR_FEAT_BIT                BIT(1)
 #define SPINAND_HAS_PROG_PLANE_SELECT_BIT              BIT(2)
 #define SPINAND_HAS_READ_PLANE_SELECT_BIT              BIT(3)
+#define SPINAND_NO_RAW_ACCESS                          BIT(4)
 
 /**
  * struct spinand_ondie_ecc_conf - private SPI-NAND on-die ECC engine structure