mtd/spinand: rework detect procedure for different READ_ID operation

Currently there are 3 different variants of read_id implementation:
1. opcode only. Found in GD5FxGQ4xF.
2. opcode + 1 addr byte. Found in GD5GxGQ4xA/E
3. opcode + 1 dummy byte. Found in other currently supported chips.

Original implementation was for variant 1 and let detect function
of chips with variant 2 and 3 to ignore the first byte. This isn't
robust:

1. For chips of variant 2, if SPI master doesn't keep MOSI low
during read, chip will get a random id offset, and the entire id
buffer will shift by that offset, causing detect failure.

2. For chips of variant 1, if it happens to get a devid that equals
to manufacture id of variant 2 or 3 chips, it'll get incorrectly
detected.

This patch reworks detect procedure to address problems above. New
logic do detection for all variants separatedly, in 1-2-3 order.
Since all current detect methods do exactly the same id matching
procedure, unify them into core.c and remove detect method from
manufacture_ops.

This is a rework of Chuanhong Guo <gch981213@gmail.com> patch
submitted to linux kernel

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/all/20230110115843.391630-1-frieder@fris.de
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

1 files changed, 65 insertions, 39 deletions

diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index 4ee11e812d8..597125c6a3e 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -17,6 +17,7 @@
 #include <linux/mtd/spinand.h>
 #include <linux/of.h>
 #include <linux/slab.h>
+#include <linux/string.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/spi-mem.h>
 #else
@@ -452,9 +453,11 @@ out:
 	return status & STATUS_BUSY ? -ETIMEDOUT : 0;
 }
 
-static int spinand_read_id_op(struct spinand_device *spinand, u8 *buf)
+static int spinand_read_id_op(struct spinand_device *spinand, u8 naddr,
+			      u8 ndummy, u8 *buf)
 {
-	struct spi_mem_op op = SPINAND_READID_OP(0, spinand->scratchbuf,
+	struct spi_mem_op op = SPINAND_READID_OP(naddr, ndummy,
+						 spinand->scratchbuf,
 						 SPINAND_MAX_ID_LEN);
 	int ret;
 
@@ -808,21 +811,6 @@ static int spinand_mtd_block_isreserved(struct mtd_info *mtd, loff_t offs)
 	return ret;
 }
 
-const struct spi_mem_op *
-spinand_find_supported_op(struct spinand_device *spinand,
-			  const struct spi_mem_op *ops,
-			  unsigned int nops)
-{
-	unsigned int i;
-
-	for (i = 0; i < nops; i++) {
-		if (spi_mem_supports_op(spinand->slave, &ops[i]))
-			return &ops[i];
-	}
-
-	return NULL;
-}
-
 static const struct nand_ops spinand_ops = {
 	.erase = spinand_erase,
 	.markbad = spinand_markbad,
@@ -837,24 +825,62 @@ static const struct spinand_manufacturer *spinand_manufacturers[] = {
 	&winbond_spinand_manufacturer,
 };
 
-static int spinand_manufacturer_detect(struct spinand_device *spinand)
+static int spinand_manufacturer_match(struct spinand_device *spinand,
+				      enum spinand_readid_method rdid_method)
 {
+	u8 *id = spinand->id.data;
 	unsigned int i;
 	int ret;
 
 	for (i = 0; i < ARRAY_SIZE(spinand_manufacturers); i++) {
-		ret = spinand_manufacturers[i]->ops->detect(spinand);
-		if (ret > 0) {
-			spinand->manufacturer = spinand_manufacturers[i];
-			return 0;
-		} else if (ret < 0) {
-			return ret;
-		}
-	}
+		const struct spinand_manufacturer *manufacturer =
+			spinand_manufacturers[i];
 
+		if (id[0] != manufacturer->id)
+			continue;
+
+		ret = spinand_match_and_init(spinand,
+					     manufacturer->chips,
+					     manufacturer->nchips,
+					     rdid_method);
+		if (ret < 0)
+			continue;
+
+		spinand->manufacturer = manufacturer;
+		return 0;
+	}
 	return -ENOTSUPP;
 }
 
+static int spinand_id_detect(struct spinand_device *spinand)
+{
+	u8 *id = spinand->id.data;
+	int ret;
+
+	ret = spinand_read_id_op(spinand, 0, 0, id);
+	if (ret)
+		return ret;
+	ret = spinand_manufacturer_match(spinand, SPINAND_READID_METHOD_OPCODE);
+	if (!ret)
+		return 0;
+
+	ret = spinand_read_id_op(spinand, 1, 0, id);
+	if (ret)
+		return ret;
+	ret = spinand_manufacturer_match(spinand,
+					 SPINAND_READID_METHOD_OPCODE_ADDR);
+	if (!ret)
+		return 0;
+
+	ret = spinand_read_id_op(spinand, 0, 1, id);
+	if (ret)
+		return ret;
+	ret = spinand_manufacturer_match(spinand,
+					 SPINAND_READID_METHOD_OPCODE_DUMMY);
+
+	return ret;
+}
+
 static int spinand_manufacturer_init(struct spinand_device *spinand)
 {
 	if (spinand->manufacturer->ops->init)
@@ -910,9 +936,9 @@ spinand_select_op_variant(struct spinand_device *spinand,
  * @spinand: SPI NAND object
  * @table: SPI NAND device description table
  * @table_size: size of the device description table
+ * @rdid_method: read id method to match
  *
- * Should be used by SPI NAND manufacturer drivers when they want to find a
- * match between a device ID retrieved through the READ_ID command and an
+ * Match between a device ID retrieved through the READ_ID command and an
  * entry in the SPI NAND description table. If a match is found, the spinand
  * object will be initialized with information provided by the matching
  * spinand_info entry.
@@ -921,8 +947,10 @@ spinand_select_op_variant(struct spinand_device *spinand,
  */
 int spinand_match_and_init(struct spinand_device *spinand,
 			   const struct spinand_info *table,
-			   unsigned int table_size, u8 devid)
+			   unsigned int table_size,
+			   enum spinand_readid_method rdid_method)
 {
+	u8 *id = spinand->id.data;
 	struct nand_device *nand = spinand_to_nand(spinand);
 	unsigned int i;
 
@@ -930,13 +958,17 @@ int spinand_match_and_init(struct spinand_device *spinand,
 		const struct spinand_info *info = &table[i];
 		const struct spi_mem_op *op;
 
-		if (devid != info->devid)
+		if (rdid_method != info->devid.method)
+			continue;
+
+		if (memcmp(id + 1, info->devid.id, info->devid.len))
 			continue;
 
 		nand->memorg = table[i].memorg;
 		nand->eccreq = table[i].eccreq;
 		spinand->eccinfo = table[i].eccinfo;
 		spinand->flags = table[i].flags;
+		spinand->id.len = 1 + table[i].devid.len;
 		spinand->select_target = table[i].select_target;
 
 		op = spinand_select_op_variant(spinand,
@@ -972,13 +1004,7 @@ static int spinand_detect(struct spinand_device *spinand)
 	if (ret)
 		return ret;
 
-	ret = spinand_read_id_op(spinand, spinand->id.data);
-	if (ret)
-		return ret;
-
-	spinand->id.len = SPINAND_MAX_ID_LEN;
-
-	ret = spinand_manufacturer_detect(spinand);
+	ret = spinand_id_detect(spinand);
 	if (ret) {
 		dev_err(spinand->slave->dev, "unknown raw ID %02x %02x %02x %02x\n",
 			spinand->id.data[0], spinand->id.data[1],
@@ -1083,11 +1109,11 @@ static int spinand_init(struct spinand_device *spinand)
 	for (i = 0; i < nand->memorg.ntargets; i++) {
 		ret = spinand_select_target(spinand, i);
 		if (ret)
-			goto err_free_bufs;
+			goto err_manuf_cleanup;
 
 		ret = spinand_lock_block(spinand, BL_ALL_UNLOCKED);
 		if (ret)
-			goto err_free_bufs;
+			goto err_manuf_cleanup;
 	}
 
 	ret = nanddev_init(nand, &spinand_ops, THIS_MODULE);