mtd: spi-nor: factor out replace-able flash_{lock,unlock}

Flash lock/unlock is a flash-specific operations. Factor out a callback
for it to more readily support other vendors.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Tested-by: NVIET NGA DAO <vndao@altera.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -369,17 +369,13 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 	return ret;
 }
 
-static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
-	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	struct mtd_info *mtd = nor->mtd;
 	uint32_t offset = ofs;
 	uint8_t status_old, status_new;
 	int ret = 0;
 
-	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
-	if (ret)
-		return ret;
-
 	status_old = read_sr(nor);
 
 	if (offset < mtd->size - (mtd->size / 2))
@@ -402,26 +398,18 @@ static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 				(status_old & (SR_BP2 | SR_BP1 | SR_BP0))) {
 		write_enable(nor);
 		ret = write_sr(nor, status_new);
-		if (ret)
-			goto err;
 	}
 
-err:
-	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
 	return ret;
 }
 
-static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
-	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	struct mtd_info *mtd = nor->mtd;
 	uint32_t offset = ofs;
 	uint8_t status_old, status_new;
 	int ret = 0;
 
-	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
-	if (ret)
-		return ret;
-
 	status_old = read_sr(nor);
 
 	if (offset+len > mtd->size - (mtd->size / 64))
@@ -444,15 +432,41 @@ static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 				(status_old & (SR_BP2 | SR_BP1 | SR_BP0))) {
 		write_enable(nor);
 		ret = write_sr(nor, status_new);
-		if (ret)
-			goto err;
 	}
 
-err:
+	return ret;
+}
+
+static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	int ret;
+
+	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
+	if (ret)
+		return ret;
+
+	ret = nor->flash_lock(nor, ofs, len);
+
 	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
 	return ret;
 }
 
+static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+	struct spi_nor *nor = mtd_to_spi_nor(mtd);
+	int ret;
+
+	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
+	if (ret)
+		return ret;
+
+	ret = nor->flash_unlock(nor, ofs, len);
+
+	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
+	return ret;
+}
+
 /* Used when the "_ext_id" is two bytes at most */
 #define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
 	((kernel_ulong_t)&(struct flash_info) {				\
@@ -1045,6 +1059,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 
 	/* nor protection support for STmicro chips */
 	if (JEDEC_MFR(info) == CFI_MFR_ST) {
+		nor->flash_lock = stm_lock;
+		nor->flash_unlock = stm_unlock;
+	}
+
+	if (nor->flash_lock && nor->flash_unlock) {
 		mtd->_lock = spi_nor_lock;
 		mtd->_unlock = spi_nor_unlock;
 	}

include/linux/mtd/spi-nor.h

@@ -155,6 +155,8 @@ enum spi_nor_option_flags {
  * @write:		[DRIVER-SPECIFIC] write data to the SPI NOR
  * @erase:		[DRIVER-SPECIFIC] erase a sector of the SPI NOR
  *			at the offset @offs
+ * @lock:		[FLASH-SPECIFIC] lock a region of the SPI NOR
+ * @unlock:		[FLASH-SPECIFIC] unlock a region of the SPI NOR
  * @priv:		the private data
  */
 struct spi_nor {
@@ -189,6 +191,9 @@ struct spi_nor {
 			size_t len, size_t *retlen, const u_char *write_buf);
 	int (*erase)(struct spi_nor *nor, loff_t offs);
 
+	int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+	int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+
 	void *priv;
 };