[PATCH] [MTD] CHIPS: 0xFF intolerance for M29W128G

[massimo cirillo]

From: Massimo Cirillo <maxcir at gmail.com>

The M29W128G Numonyx flash devices are intolerant to any 0xFF command:
in the Cfi_util.c the function cfi_qry_mode_off() (that resets the device
after the autoselect mode) must have a 0xF0 command after the 0xFF command.
Intel-like devices are not influenced by a 0xF0 command.
This fix solves also the cause of the fixup_M29W128G_write_buffer() fix,
that can be commented out now.
The following patch applies to 2.6.30 kernel.

Signed-off-by: Massimo Cirillo <maxcir at gmail.com>
---
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c
b/drivers/mtd/chips/cfi_cmdset_0002.c
old mode 100644
new mode 100755
index 61ea833..5a65e92
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -308,7 +308,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
 	{ CFI_MFR_AMD, 0x1301, fixup_s29gl064n_sectors, NULL, },
 	{ CFI_MFR_AMD, 0x1a00, fixup_s29gl032n_sectors, NULL, },
 	{ CFI_MFR_AMD, 0x1a01, fixup_s29gl032n_sectors, NULL, },
-	{ CFI_MFR_ST,  0x227E, fixup_M29W128G_write_buffer, NULL, },
+	/*{ CFI_MFR_ST,  0x227E, fixup_M29W128G_write_buffer, NULL, },*/
 #if !FORCE_WORD_WRITE
 	{ CFI_MFR_ANY, CFI_ID_ANY, fixup_use_write_buffers, NULL, },
 #endif
diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
old mode 100644
new mode 100755
index 34d40e2..9c897f9
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -61,8 +61,8 @@ int __xipram cfi_qry_mode_on(uint32_t base,
 		return 1;
 	/* QRY not found probably we deal with some odd CFI chips */
 	/* Some revisions of some old Intel chips? */
-	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
 	if (cfi_qry_present(map, base, cfi))
 		return 1;
@@ -79,8 +79,11 @@ EXPORT_SYMBOL_GPL(cfi_qry_mode_on);
 void __xipram cfi_qry_mode_off(uint32_t base, struct map_info *map,
 			       struct cfi_private *cfi)
 {
-	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 	cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
+    /* Numonyx M29W128G requires two 0xF0 to exit succesfully from
+    autoselect mode. No consequences on Intel-like devices. */
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
 }
 EXPORT_SYMBOL_GPL(cfi_qry_mode_off);

--