[PATCH 6/7] mtd/spinand: add Winbond W25N02KV flash support, fix Winbond flashes identifications

[mikhail.kshevetskiy at iopsys.eu]

From: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>

Winbond uses 3 bytes to identify flash: vendor_id, dev_id_0, dev_id_1,
but current driver uses only first 2 bytes of it for devices
idenfification. As result Winbond W25N02KV flash (id_bytes: EF, AA, 22)
is identified as W25N01GV (id_bytes: EF, AA, 21).

Fix this and add W25N02KV flash support.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
---
 drivers/mtd/nand/spi/winbond.c | 80 +++++++++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/spi/winbond.c b/drivers/mtd/nand/spi/winbond.c
index 7f991ed75e..19e5c863e8 100644
--- a/drivers/mtd/nand/spi/winbond.c
+++ b/drivers/mtd/nand/spi/winbond.c
@@ -11,6 +11,7 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #endif
+#include <linux/bug.h>
 #include <linux/mtd/spinand.h>
 
 #define SPINAND_MFR_WINBOND		0xEF
@@ -76,9 +77,75 @@ static int w25m02gv_select_target(struct spinand_device *spinand,
 	return spi_mem_exec_op(spinand->slave, &op);
 }
 
+static int w25n02kv_ooblayout_ecc(struct mtd_info *mtd, int section,
+				  struct mtd_oob_region *region)
+{
+	if (section > 3)
+		return -ERANGE;
+
+	region->offset = 64 + (16 * section);
+	region->length = 13;
+
+	return 0;
+}
+
+static int w25n02kv_ooblayout_free(struct mtd_info *mtd, int section,
+				   struct mtd_oob_region *region)
+{
+	if (section > 3)
+		return -ERANGE;
+
+	region->offset = (16 * section) + 2;
+	region->length = 14;
+
+	return 0;
+}
+
+static const struct mtd_ooblayout_ops w25n02kv_ooblayout = {
+	.ecc = w25n02kv_ooblayout_ecc,
+	.free = w25n02kv_ooblayout_free,
+};
+
+static int w25n02kv_ecc_get_status(struct spinand_device *spinand,
+				   u8 status)
+{
+	struct nand_device *nand = spinand_to_nand(spinand);
+	u8 mbf = 0;
+	struct spi_mem_op op = SPINAND_GET_FEATURE_OP(0x30, &mbf);
+
+	switch (status & STATUS_ECC_MASK) {
+	case STATUS_ECC_NO_BITFLIPS:
+		return 0;
+
+	case STATUS_ECC_UNCOR_ERROR:
+		return -EBADMSG;
+
+	case STATUS_ECC_HAS_BITFLIPS:
+		/*
+		 * Let's try to retrieve the real maximum number of bitflips
+		 * in order to avoid forcing the wear-leveling layer to move
+		 * data around if it's not necessary.
+		 */
+		if (spi_mem_exec_op(spinand->slave, &op))
+			return nand->eccreq.strength;
+
+		mbf >>= 4;
+
+		if (WARN_ON(mbf > nand->eccreq.strength || !mbf))
+			return nand->eccreq.strength;
+
+		return mbf;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
 static const struct spinand_info winbond_spinand_table[] = {
 	SPINAND_INFO("W25M02GV",
-		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xab),
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xab, 0x21),
 		     NAND_MEMORG(1, 2048, 64, 64, 1024, 20, 1, 1, 2),
 		     NAND_ECCREQ(1, 512),
 		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
@@ -88,7 +155,7 @@ static const struct spinand_info winbond_spinand_table[] = {
 		     SPINAND_ECCINFO(&w25m02gv_ooblayout, NULL),
 		     SPINAND_SELECT_TARGET(w25m02gv_select_target)),
 	SPINAND_INFO("W25N01GV",
-		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xaa),
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xaa, 0x21),
 		     NAND_MEMORG(1, 2048, 64, 64, 1024, 20, 1, 1, 1),
 		     NAND_ECCREQ(1, 512),
 		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
@@ -96,6 +163,15 @@ static const struct spinand_info winbond_spinand_table[] = {
 					      &update_cache_variants),
 		     0,
 		     SPINAND_ECCINFO(&w25m02gv_ooblayout, NULL)),
+	SPINAND_INFO("W25N02KV",
+		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_DUMMY, 0xaa, 0x22),
+		     NAND_MEMORG(1, 2048, 128, 64, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     0,
+		     SPINAND_ECCINFO(&w25n02kv_ooblayout, w25n02kv_ecc_get_status)),
 };
 
 static int winbond_spinand_init(struct spinand_device *spinand)
-- 
2.35.1