[PATCH] mtd: spi-nor: Add possibility to disable chip erase

[marcin.krzeminski at nokia.com]

From: Marcin Krzeminski <marcin.krzeminski at nokia.com>

n25q00 does not support chip erase command (0xC7),
but spi-nor framework still send if if user want to erase
whole flash. This patch adds option to disable chip erase
command and enable in on n25q00.

Signed-off-by: Marcin Krzeminski <marcin.krzeminski at nokia.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 9 ++++++---
 include/linux/mtd/spi-nor.h   | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d0fc165..8338be1 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -75,6 +75,7 @@ struct flash_info {
 					 * bit. Must be used with
 					 * SPI_NOR_HAS_LOCK.
 					 */
+#define DISABLE_CE			BIT(10)	/*Some multi-die flash does not support CE */
 };
 
 #define JEDEC_MFR(info)	((info)->id[0])
@@ -368,7 +369,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 		return ret;
 
 	/* whole-chip erase? */
-	if (len == mtd->size) {
+	if (len == mtd->size && !(nor->flags & SNOR_F_DISABLE_CE)) {
 		unsigned long timeout;
 
 		write_enable(nor);
@@ -886,8 +887,8 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "n25q256a",    INFO(0x20ba19, 0, 64 * 1024,  512, SECT_4K | SPI_NOR_QUAD_READ) },
 	{ "n25q512a",    INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
 	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
-	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
-	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
+	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | DISABLE_CE) },
+	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | DISABLE_CE) },
 
 	/* PMC */
 	{ "pm25lv512",   INFO(0,        0, 32 * 1024,    2, SECT_4K_PMC) },
@@ -1395,6 +1396,8 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 		nor->flags |= SNOR_F_USE_FSR;
 	if (info->flags & SPI_NOR_HAS_TB)
 		nor->flags |= SNOR_F_HAS_SR_TB;
+	if (info->flags & DISABLE_CE)
+		nor->flags |= SNOR_F_DISABLE_CE;
 
 #ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
 	/* prefer "small sector" erase if possible */
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index c425c7b..2d0b967 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -119,6 +119,7 @@ enum spi_nor_ops {
 enum spi_nor_option_flags {
 	SNOR_F_USE_FSR		= BIT(0),
 	SNOR_F_HAS_SR_TB	= BIT(1),
+	SNOR_F_DISABLE_CE	= BIT(2),
 };
 
 /**
-- 
2.7.4