generic: disable 'small sector' erase in m25p80 driver

This fixes the issues with the jffs2 images on various boards. Using
JFFS2 on devices with 4KiB erase sectors is not safe:
http://lists.infradead.org/pipermail/linux-mtd/2011-June/036591.html

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29521 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/generic/config-2.6.39

@@ -1288,6 +1288,7 @@ CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_LXT_PHY is not set
 CONFIG_LZMA_COMPRESS=y
 CONFIG_LZMA_DECOMPRESS=y
+# CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE is not set
 # CONFIG_MAC80211 is not set
 # CONFIG_MACH_DECSTATION is not set
 # CONFIG_MACH_JAZZ is not set

target/linux/generic/config-3.0

@@ -1278,6 +1278,7 @@ CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_LXT_PHY is not set
 CONFIG_LZMA_COMPRESS=y
 CONFIG_LZMA_DECOMPRESS=y
+# CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE is not set
 # CONFIG_MAC80211 is not set
 # CONFIG_MACH_DECSTATION is not set
 # CONFIG_MACH_JAZZ is not set

target/linux/generic/config-3.1

@@ -1291,6 +1291,7 @@ CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_LXT_PHY is not set
 CONFIG_LZMA_COMPRESS=y
 CONFIG_LZMA_DECOMPRESS=y
+# CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE is not set
 # CONFIG_MAC80211 is not set
 # CONFIG_MACH_DECSTATION is not set
 # CONFIG_MACH_JAZZ is not set

target/linux/generic/patches-2.6.39/475-mtd-m25p80-allow-to-disable-small-sector-erase.patch

@@ -0,0 +1,41 @@
+--- a/drivers/mtd/devices/Kconfig
++++ b/drivers/mtd/devices/Kconfig
+@@ -102,6 +102,14 @@ config M25PXX_USE_FAST_READ
+ 	help
+ 	  This option enables FAST_READ access supported by ST M25Pxx.
+ 
++config M25PXX_PREFER_SMALL_SECTOR_ERASE
++	bool "Prefer small sector erase"
++	depends on MTD_M25P80
++	default y
++	help
++	  This option enables use of the small erase sectors if that is
++	  supported by the flash chip.
++
+ config MTD_SST25L
+ 	tristate "Support SST25L (non JEDEC) SPI Flash chips"
+ 	depends on SPI_MASTER
+--- a/drivers/mtd/devices/m25p80.c
++++ b/drivers/mtd/devices/m25p80.c
+@@ -77,6 +77,12 @@
+ #define FAST_READ_DUMMY_BYTE 0
+ #endif
+ 
++#ifdef CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE
++#define PREFER_SMALL_SECTOR_ERASE 1
++#else
++#define PREFER_SMALL_SECTOR_ERASE 0
++#endif
++
+ /****************************************************************************/
+ 
+ struct m25p {
+@@ -902,7 +908,7 @@ static int __devinit m25p_probe(struct s
+ 		flash->mtd.write = m25p80_write;
+ 
+ 	/* prefer "small sector" erase if possible */
+-	if (info->flags & SECT_4K) {
++	if (PREFER_SMALL_SECTOR_ERASE && (info->flags & SECT_4K)) {
+ 		flash->erase_opcode = OPCODE_BE_4K;
+ 		flash->mtd.erasesize = 4096;
+ 	} else if (info->flags & SECT_4K_PMC) {

target/linux/generic/patches-3.0/476-mtd-m25p80-allow-to-disable-small-sector-erase.patch

@@ -0,0 +1,41 @@
+--- a/drivers/mtd/devices/Kconfig
++++ b/drivers/mtd/devices/Kconfig
+@@ -102,6 +102,14 @@ config M25PXX_USE_FAST_READ
+ 	help
+ 	  This option enables FAST_READ access supported by ST M25Pxx.
+ 
++config M25PXX_PREFER_SMALL_SECTOR_ERASE
++	bool "Prefer small sector erase"
++	depends on MTD_M25P80
++	default y
++	help
++	  This option enables use of the small erase sectors if that is
++	  supported by the flash chip.
++
+ config MTD_SST25L
+ 	tristate "Support SST25L (non JEDEC) SPI Flash chips"
+ 	depends on SPI_MASTER
+--- a/drivers/mtd/devices/m25p80.c
++++ b/drivers/mtd/devices/m25p80.c
+@@ -83,6 +83,12 @@
+ 
+ #define JEDEC_MFR(_jedec_id)	((_jedec_id) >> 16)
+ 
++#ifdef CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE
++#define PREFER_SMALL_SECTOR_ERASE 1
++#else
++#define PREFER_SMALL_SECTOR_ERASE 0
++#endif
++
+ /****************************************************************************/
+ 
+ struct m25p {
+@@ -924,7 +930,7 @@ static int __devinit m25p_probe(struct s
+ 		flash->mtd.write = m25p80_write;
+ 
+ 	/* prefer "small sector" erase if possible */
+-	if (info->flags & SECT_4K) {
++	if (PREFER_SMALL_SECTOR_ERASE && (info->flags & SECT_4K)) {
+ 		flash->erase_opcode = OPCODE_BE_4K;
+ 		flash->mtd.erasesize = 4096;
+ 	} else if (info->flags & SECT_4K_PMC) {

target/linux/generic/patches-3.1/476-mtd-m25p80-allow-to-disable-small-sector-erase.patch

@@ -0,0 +1,41 @@
+--- a/drivers/mtd/devices/Kconfig
++++ b/drivers/mtd/devices/Kconfig
+@@ -102,6 +102,14 @@ config M25PXX_USE_FAST_READ
+ 	help
+ 	  This option enables FAST_READ access supported by ST M25Pxx.
+ 
++config M25PXX_PREFER_SMALL_SECTOR_ERASE
++	bool "Prefer small sector erase"
++	depends on MTD_M25P80
++	default y
++	help
++	  This option enables use of the small erase sectors if that is
++	  supported by the flash chip.
++
+ config MTD_SST25L
+ 	tristate "Support SST25L (non JEDEC) SPI Flash chips"
+ 	depends on SPI_MASTER
+--- a/drivers/mtd/devices/m25p80.c
++++ b/drivers/mtd/devices/m25p80.c
+@@ -83,6 +83,12 @@
+ 
+ #define JEDEC_MFR(_jedec_id)	((_jedec_id) >> 16)
+ 
++#ifdef CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE
++#define PREFER_SMALL_SECTOR_ERASE 1
++#else
++#define PREFER_SMALL_SECTOR_ERASE 0
++#endif
++
+ /****************************************************************************/
+ 
+ struct m25p {
+@@ -924,7 +930,7 @@ static int __devinit m25p_probe(struct s
+ 		flash->mtd.write = m25p80_write;
+ 
+ 	/* prefer "small sector" erase if possible */
+-	if (info->flags & SECT_4K) {
++	if (PREFER_SMALL_SECTOR_ERASE && (info->flags & SECT_4K)) {
+ 		flash->erase_opcode = OPCODE_BE_4K;
+ 		flash->mtd.erasesize = 4096;
+ 	} else if (info->flags & SECT_4K_PMC) {