From 1ba639da5604a64b3ed884a2cbb1c5414a9fa728 Mon Sep 17 00:00:00 2001
From: Michael Schwingen <michael@schwingen.org>
Date: Mon, 18 Feb 2008 23:16:35 +0100
Subject: [PATCH] CFI: Do not use uninitialized cmd_reset
Do not use uninitialized cmd_reset; issue both AMD and Intel reset
commands instead
From a short test, it looks like AMD-style flash roms treat *any* unknown
command write as a reset, at least when in CFI Query mode, so issuing the
Intel reset command to AMD-style flashs seems safe (from the small sample I
have), plus the 3-cycle magic sequence should kick the state machine into
the right state even without a reset command. Since the AMD-style flashs
require the unlock sequence for real operation, I chose to try the AMD reset
command first, so that Intel flashs do no see an invalid command prior to
the CFI query.
I have tested the patch on AM29LV320-style flashs from Fujitsu and Macronix,
plus Intel StrataFlash.
Signed-off-by: Michael Schwingen <michael@schwingen.org>
Signed-off-by: Stefan Roese <sr@denx.de>
---
drivers/mtd/cfi_flash.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index eb509f55571..439c950cf22 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -1538,7 +1538,12 @@ static int __flash_detect_cfi (flash_info_t * info, struct cfi_qry *qry)
{
int cfi_offset;
- flash_write_cmd (info, 0, 0, info->cmd_reset);
+ /* We do not yet know what kind of commandset to use, so we issue
+ the reset command in both Intel and AMD variants, in the hope
+ that AMD flash roms ignore the Intel command. */
+ flash_write_cmd (info, 0, 0, AMD_CMD_RESET);
+ flash_write_cmd (info, 0, 0, FLASH_CMD_RESET);
+
for (cfi_offset=0;
cfi_offset < sizeof(flash_offset_cfi) / sizeof(uint);
cfi_offset++) {
--
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