mtd: nand: Do not expose the NAND manufacturer table directly

There is no reason to expose the NAND manufacturer table. Provide an
helper function to find manufacturers by their id.

We also turn the nand_manufacturers table into a const array, since its
members are not modified after the initial assignment.

Finally, we remove the sentinel manufacturer entry from the manufacturers
table (we already have the array size information given by ARRAY_SIZE()),
and add the nand_manufacturer_name() helper to handle the "Unknown" case
properly.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/nand_base.c

@@ -4052,9 +4052,10 @@ static bool find_full_id_nand(struct nand_chip *chip,
  */
 static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
 {
+	const struct nand_manufacturer *manufacturer;
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	int busw;
-	int i, maf_idx;
+	int i;
 	u8 *id_data = chip->id.data;
 	u8 maf_id, dev_id;
 
@@ -4159,10 +4160,7 @@ static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
 ident_done:
 
 	/* Try to identify manufacturer */
-	for (maf_idx = 0; nand_manuf_ids[maf_idx].id != 0x0; maf_idx++) {
-		if (nand_manuf_ids[maf_idx].id == maf_id)
-			break;
-	}
+	manufacturer = nand_get_manufacturer(maf_id);
 
 	if (chip->options & NAND_BUSWIDTH_AUTO) {
 		WARN_ON(busw & NAND_BUSWIDTH_16);
@@ -4174,7 +4172,8 @@ static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
 		 */
 		pr_info("device found, Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
 			maf_id, dev_id);
-		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name, mtd->name);
+		pr_info("%s %s\n", nand_manufacturer_name(manufacturer),
+			mtd->name);
 		pr_warn("bus width %d instead of %d bits\n", busw ? 16 : 8,
 			(chip->options & NAND_BUSWIDTH_16) ? 16 : 8);
 		return -EINVAL;
@@ -4207,14 +4206,14 @@ static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
 		maf_id, dev_id);
 
 	if (chip->onfi_version)
-		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
-				chip->onfi_params.model);
+		pr_info("%s %s\n", nand_manufacturer_name(manufacturer),
+			chip->onfi_params.model);
 	else if (chip->jedec_version)
-		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
-				chip->jedec_params.model);
+		pr_info("%s %s\n", nand_manufacturer_name(manufacturer),
+			chip->jedec_params.model);
 	else
-		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
-				type->name);
+		pr_info("%s %s\n", nand_manufacturer_name(manufacturer),
+			type->name);
 
 	pr_info("%d MiB, %s, erase size: %d KiB, page size: %d, OOB size: %d\n",
 		(int)(chip->chipsize >> 20), nand_is_slc(chip) ? "SLC" : "MLC",

drivers/mtd/nand/nand_ids.c

@@ -169,7 +169,7 @@ struct nand_flash_dev nand_flash_ids[] = {
 };
 
 /* Manufacturer IDs */
-struct nand_manufacturer nand_manuf_ids[] = {
+static const struct nand_manufacturer nand_manufacturers[] = {
 	{NAND_MFR_TOSHIBA, "Toshiba"},
 	{NAND_MFR_ESMT, "ESMT"},
 	{NAND_MFR_SAMSUNG, "Samsung"},
@@ -186,5 +186,23 @@ struct nand_manufacturer nand_manuf_ids[] = {
 	{NAND_MFR_INTEL, "Intel"},
 	{NAND_MFR_ATO, "ATO"},
 	{NAND_MFR_WINBOND, "Winbond"},
-	{0x0, "Unknown"}
 };
+
+/**
+ * nand_get_manufacturer - Get manufacturer information from the manufacturer
+ *			   ID
+ * @id: manufacturer ID
+ *
+ * Returns a pointer a nand_manufacturer object if the manufacturer is defined
+ * in the NAND manufacturers database, NULL otherwise.
+ */
+const struct nand_manufacturer *nand_get_manufacturer(u8 id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(nand_manufacturers); i++)
+		if (nand_manufacturers[i].id == id)
+			return &nand_manufacturers[i];
+
+	return NULL;
+}

include/linux/mtd/nand.h

@@ -1071,8 +1071,15 @@ struct nand_manufacturer {
 	char *name;
 };
 
+const struct nand_manufacturer *nand_get_manufacturer(u8 id);
+
+static inline const char *
+nand_manufacturer_name(const struct nand_manufacturer *manufacturer)
+{
+	return manufacturer ? manufacturer->name : "Unknown";
+}
+
 extern struct nand_flash_dev nand_flash_ids[];
-extern struct nand_manufacturer nand_manuf_ids[];
 
 int nand_default_bbt(struct mtd_info *mtd);
 int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs);