mtd: spi-nor: Rework the SPI NOR lock/unlock logic

Add the SNOR_F_HAS_LOCK flag and set it when SPI_NOR_HAS_LOCK is set
in the flash_info entry or when it's a Micron or ST flash.

Move the locking hooks in a separate struct so that we have just
one field to update when we change the locking implementation.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
[tudor.ambarus@microchip.com: use ->default_init() hook, introduce
spi_nor_late_init_params(), set ops in nor->params]
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>

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

@@ -1598,6 +1598,12 @@ static int stm_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
 	return stm_is_locked_sr(nor, ofs, len, status);
 }
 
+static const struct spi_nor_locking_ops stm_locking_ops = {
+	.lock = stm_lock,
+	.unlock = stm_unlock,
+	.is_locked = stm_is_locked,
+};
+
 static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 {
 	struct spi_nor *nor = mtd_to_spi_nor(mtd);
@@ -1607,7 +1613,7 @@ static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	if (ret)
 		return ret;
 
-	ret = nor->flash_lock(nor, ofs, len);
+	ret = nor->params.locking_ops->lock(nor, ofs, len);
 
 	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
 	return ret;
@@ -1622,7 +1628,7 @@ static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	if (ret)
 		return ret;
 
-	ret = nor->flash_unlock(nor, ofs, len);
+	ret = nor->params.locking_ops->unlock(nor, ofs, len);
 
 	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
 	return ret;
@@ -1637,7 +1643,7 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	if (ret)
 		return ret;
 
-	ret = nor->flash_is_locked(nor, ofs, len);
+	ret = nor->params.locking_ops->is_locked(nor, ofs, len);
 
 	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
 	return ret;
@@ -4148,6 +4154,7 @@ static void macronix_set_default_init(struct spi_nor *nor)
 
 static void st_micron_set_default_init(struct spi_nor *nor)
 {
+	nor->flags |= SNOR_F_HAS_LOCK;
 	nor->params.quad_enable = NULL;
 	nor->params.set_4byte = st_micron_set_4byte;
 }
@@ -4291,6 +4298,23 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
 	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
 }
 
+/**
+ * spi_nor_late_init_params() - Late initialization of default flash parameters.
+ * @nor:	pointer to a 'struct spi_nor'
+ *
+ * Used to set default flash parameters and settings when the ->default_init()
+ * hook or the SFDP parser let voids.
+ */
+static void spi_nor_late_init_params(struct spi_nor *nor)
+{
+	/*
+	 * NOR protection support. When locking_ops are not provided, we pick
+	 * the default ones.
+	 */
+	if (nor->flags & SNOR_F_HAS_LOCK && !nor->params.locking_ops)
+		nor->params.locking_ops = &stm_locking_ops;
+}
+
 /**
  * spi_nor_init_params() - Initialize the flash's parameters and settings.
  * @nor:	pointer to a 'struct spi-nor'.
@@ -4316,6 +4340,10 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
  *    Please note that there is a ->post_bfpt() fixup hook that can overwrite
  *    the flash parameters and settings immediately after parsing the Basic
  *    Flash Parameter Table.
+ *
+ * 4/ Late default flash parameters initialization, used when the
+ * ->default_init() hook or the SFDP parser do not set specific params.
+ *		spi_nor_late_init_params()
  */
 static void spi_nor_init_params(struct spi_nor *nor)
 {
@@ -4326,6 +4354,8 @@ static void spi_nor_init_params(struct spi_nor *nor)
 	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
 	    !(nor->info->flags & SPI_NOR_SKIP_SFDP))
 		spi_nor_sfdp_init_params(nor);
+
+	spi_nor_late_init_params(nor);
 }
 
 static int spi_nor_select_read(struct spi_nor *nor,
@@ -4707,6 +4737,9 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	if (info->flags & SPI_S3AN)
 		nor->flags |=  SNOR_F_READY_XSR_RDY;
 
+	if (info->flags & SPI_NOR_HAS_LOCK)
+		nor->flags |= SNOR_F_HAS_LOCK;
+
 	/*
 	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
 	 * with the software protection bits set.
@@ -4731,16 +4764,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	mtd->_read = spi_nor_read;
 	mtd->_resume = spi_nor_resume;
 
-	/* NOR protection support for STmicro/Micron chips and similar */
-	if (JEDEC_MFR(info) == SNOR_MFR_ST ||
-	    JEDEC_MFR(info) == SNOR_MFR_MICRON ||
-	    info->flags & SPI_NOR_HAS_LOCK) {
-		nor->flash_lock = stm_lock;
-		nor->flash_unlock = stm_unlock;
-		nor->flash_is_locked = stm_is_locked;
-	}
-
-	if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) {
+	if (nor->params.locking_ops) {
 		mtd->_lock = spi_nor_lock;
 		mtd->_unlock = spi_nor_unlock;
 		mtd->_is_locked = spi_nor_is_locked;

include/linux/mtd/spi-nor.h

@@ -243,6 +243,7 @@ enum spi_nor_option_flags {
 	SNOR_F_BROKEN_RESET	= BIT(6),
 	SNOR_F_4B_OPCODES	= BIT(7),
 	SNOR_F_HAS_4BAIT	= BIT(8),
+	SNOR_F_HAS_LOCK		= BIT(9),
 };
 
 /**
@@ -465,6 +466,18 @@ enum spi_nor_pp_command_index {
 /* Forward declaration that will be used in 'struct spi_nor_flash_parameter' */
 struct spi_nor;
 
+/**
+ * struct spi_nor_locking_ops - SPI NOR locking methods
+ * @lock:	lock a region of the SPI NOR.
+ * @unlock:	unlock a region of the SPI NOR.
+ * @is_locked:	check if a region of the SPI NOR is completely locked
+ */
+struct spi_nor_locking_ops {
+	int (*lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+	int (*unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+	int (*is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+};
+
 /**
  * struct spi_nor_flash_parameter - SPI NOR flash parameters and settings.
  * Includes legacy flash parameters and settings that can be overwritten
@@ -483,6 +496,7 @@ struct spi_nor;
  *                      Table.
  * @quad_enable:	enables SPI NOR quad mode.
  * @set_4byte:		puts the SPI NOR in 4 byte addressing mode.
+ * @locking_ops:	SPI NOR locking methods.
  */
 struct spi_nor_flash_parameter {
 	u64				size;
@@ -496,6 +510,8 @@ struct spi_nor_flash_parameter {
 
 	int (*quad_enable)(struct spi_nor *nor);
 	int (*set_4byte)(struct spi_nor *nor, bool enable);
+
+	const struct spi_nor_locking_ops *locking_ops;
 };
 
 /**
@@ -536,10 +552,6 @@ struct flash_info;
  * @erase:		[DRIVER-SPECIFIC] erase a sector of the SPI NOR
  *			at the offset @offs; if not provided by the driver,
  *			spi-nor will send the erase opcode via write_reg()
- * @flash_lock:		[FLASH-SPECIFIC] lock a region of the SPI NOR
- * @flash_unlock:	[FLASH-SPECIFIC] unlock a region of the SPI NOR
- * @flash_is_locked:	[FLASH-SPECIFIC] check if a region of the SPI NOR is
- *			completely locked
  * @clear_sr_bp:	[FLASH-SPECIFIC] clears the Block Protection Bits from
  *			the SPI NOR Status Register.
  * @params:		[FLASH-SPECIFIC] SPI-NOR flash parameters and settings.
@@ -579,9 +591,6 @@ struct spi_nor {
 			size_t len, 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);
-	int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
 	int (*clear_sr_bp)(struct spi_nor *nor);
 	struct spi_nor_flash_parameter params;