[MTD] [NOR] Add support for flash chips with ID in bank other than 0

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=5c9c11e1c47c2101253a95c54ef72e13edcc728a
Commit:     5c9c11e1c47c2101253a95c54ef72e13edcc728a
Parent:     8fd310a1cc3aadb7a17d844beeefae66b1a169c6
Author:     Mike Rapoport <mike at compulab.co.il>
AuthorDate: Tue May 27 11:20:03 2008 +0300
Committer:  David Woodhouse <dwmw2 at infradead.org>
CommitDate: Wed Jun 4 17:22:59 2008 +0100

    [MTD] [NOR] Add support for flash chips with ID in bank other than 0
    
    According to JEDEC "Standard Manufacturer's Identification Code"
    (http://www.jedec.org/download/search/jep106W.pdf)
    several first banks of NOR flash can contain 0x7f instead of actual ID.
    This patch adds support for reading manufacturer ID from banks other than 0.
    
    Signed-off-by: Mike Rapoport <mike at compulab.co.il>
    Signed-off-by: David Woodhouse <dwmw2 at infradead.org>
---
 drivers/mtd/chips/jedec_probe.c |   19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/chips/jedec_probe.c b/drivers/mtd/chips/jedec_probe.c
index b717f1a..279fe60 100644
--- a/drivers/mtd/chips/jedec_probe.c
+++ b/drivers/mtd/chips/jedec_probe.c
@@ -37,6 +37,7 @@
 #define MANUFACTURER_ST		0x0020
 #define MANUFACTURER_TOSHIBA	0x0098
 #define MANUFACTURER_WINBOND	0x00da
+#define CONTINUATION_CODE	0x007f
 
 
 /* AMD */
@@ -1760,9 +1761,21 @@ static inline u32 jedec_read_mfr(struct map_info *map, uint32_t base,
 {
 	map_word result;
 	unsigned long mask;
-	u32 ofs = cfi_build_cmd_addr(0, cfi_interleave(cfi), cfi->device_type);
-	mask = (1 << (cfi->device_type * 8)) -1;
-	result = map_read(map, base + ofs);
+	int bank = 0;
+
+	/* According to JEDEC "Standard Manufacturer's Identification Code"
+	 * (http://www.jedec.org/download/search/jep106W.pdf)
+	 * several first banks can contain 0x7f instead of actual ID
+	 */
+	do {
+		uint32_t ofs = cfi_build_cmd_addr(0 + (bank << 8),
+						  cfi_interleave(cfi),
+						  cfi->device_type);
+		mask = (1 << (cfi->device_type * 8)) - 1;
+		result = map_read(map, base + ofs);
+		bank++;
+	} while ((result.x[0] & mask) == CONTINUATION_CODE);
+
 	return result.x[0] & mask;
 }