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CFI: Do not use uninitialized cmd_reset

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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>
This commit is contained in:
Michael Schwingen 2008-02-18 23:16:35 +01:00 committed by Stefan Roese
parent 928d1d77f8
commit 1ba639da56
1 changed files with 6 additions and 1 deletions
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7
drivers/mtd/cfi_flash.c
View File

@ -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++) {