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From 66ec11df6561d5ba7cdf41977af828a53ba6b99f Mon Sep 17 00:00:00 2001
From: Andrea Adami <andrea.adami@gmail.com>
Date: Sat, 1 Feb 2014 13:17:24 +0100
Subject: [PATCH] mtd: cfi_util.c: force CFI detection of 2x LH28F640BF
Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
---
drivers/mtd/chips/cfi_util.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index f992418..2c7a13d 100644
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -29,6 +29,7 @@ int __xipram cfi_qry_present(struct map_info *map, __u32 base,
int osf = cfi->interleave * cfi->device_type; /* scale factor */
map_word val[3];
map_word qry[3];
+ unsigned long mask = (1 << (cfi->device_type * 8)) - 1;
qry[0] = cfi_build_cmd('Q', map, cfi);
qry[1] = cfi_build_cmd('R', map, cfi);
@@ -38,6 +39,21 @@ int __xipram cfi_qry_present(struct map_info *map, __u32 base,
val[1] = map_read(map, base + osf*0x11);
val[2] = map_read(map, base + osf*0x12);
+ /* Apparently only one of the 2 interleaved LH28F640BF 16 bit chips on
+ * a 32 bit wide bus is answering to the CFI Query.
+ * Using the expected map bankwidth=4 and chip interleave=2 we get wrong
+ * readings like 0xffff0051 instead of 0x00510051 etc.
+ * We take the valid bytes and recreate the expected answer as workaround.
+ */
+ if (((val[0].x[0] >> (cfi->device_type * 8)) == mask) &&
+ ((val[1].x[0] >> (cfi->device_type * 8)) == mask) &&
+ ((val[2].x[0] >> (cfi->device_type * 8)) == mask))
+ {
+ val[0].x[0] = (val[0].x[0] & mask) + ((val[0].x[0] & mask) << (cfi->device_type * 8));
+ val[1].x[0] = (val[1].x[0] & mask) + ((val[1].x[0] & mask) << (cfi->device_type * 8));
+ val[2].x[0] = (val[2].x[0] & mask) + ((val[2].x[0] & mask) << (cfi->device_type * 8));
+ }
+
if (!map_word_equal(map, qry[0], val[0]))
return 0;
--
1.8.1.5
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