[PATCH 1/2] mtd: spi-nor: Introduce erase_proto

[Alexander A Sverdlin <alexander.sverdlin@nokia.com>]

From: Alexander Sverdlin <alexander.sverdlin@nokia.com>

I've been looking into non-working erase on mt25qu256a and pinpointed it to
be write_proto 1-4-4 selected from SFDP while the chip only supports 1-1-0
erase.

For now just introduce the separate protocol without functional change and
leave the real fix for the following patch.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
---
 drivers/mtd/spi-nor/core.c  | 9 ++++++---
 include/linux/mtd/spi-nor.h | 4 +++-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 2e21d5a..dcd02ea 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -177,7 +177,7 @@ static int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
 
 static int spi_nor_controller_ops_erase(struct spi_nor *nor, loff_t offs)
 {
-	if (spi_nor_protocol_is_dtr(nor->write_proto))
+	if (spi_nor_protocol_is_dtr(nor->erase_proto))
 		return -EOPNOTSUPP;
 
 	return nor->controller_ops->erase(nor, offs);
@@ -1186,7 +1186,7 @@ static int spi_nor_erase_chip(struct spi_nor *nor)
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
-		spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
+		spi_nor_spimem_setup_op(nor, &op, nor->erase_proto);
 
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
@@ -1331,7 +1331,7 @@ int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_NO_DATA);
 
-		spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
+		spi_nor_spimem_setup_op(nor, &op, nor->erase_proto);
 
 		return spi_mem_exec_op(nor->spimem, &op);
 	} else if (nor->controller_ops->erase) {
@@ -2727,6 +2727,9 @@ static void spi_nor_late_init_params(struct spi_nor *nor)
 	 */
 	if (nor->flags & SNOR_F_HAS_LOCK && !nor->params->locking_ops)
 		spi_nor_init_default_locking_ops(nor);
+
+	if (!nor->erase_proto)
+		nor->erase_proto = nor->write_proto;
 }
 
 /**
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index fc90fce..23a901b 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -381,7 +381,8 @@ struct spi_nor_flash_parameter;
  * @cmd_ext_type:	the command opcode extension type for DTR mode.
  * @read_proto:		the SPI protocol for read operations
  * @write_proto:	the SPI protocol for write operations
- * @reg_proto:		the SPI protocol for read_reg/write_reg/erase operations
+ * @reg_proto:		the SPI protocol for read_reg/write_reg operations
+ * @erase_proto:	the SPI protocol for erase operations
  * @sfdp:		the SFDP data of the flash
  * @controller_ops:	SPI NOR controller driver specific operations.
  * @params:		[FLASH-SPECIFIC] SPI NOR flash parameters and settings.
@@ -408,6 +409,7 @@ struct spi_nor {
 	enum spi_nor_protocol	read_proto;
 	enum spi_nor_protocol	write_proto;
 	enum spi_nor_protocol	reg_proto;
+	enum spi_nor_protocol	erase_proto;
 	bool			sst_write_second;
 	u32			flags;
 	enum spi_nor_cmd_ext	cmd_ext_type;
-- 
2.10.2