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author | Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> | 2010-02-12 19:37:25 +0000 |
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committer | Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> | 2010-02-12 19:37:25 +0000 |
commit | e4edb067a64275ba62669ebb4b42f653cb6aff0d (patch) | |
tree | 89298b49e35ca9af4ead9eb194ac2abdcf1020ec /spi.c | |
parent | fb0828f3db2b6c298b5617690a70cc92f34f3287 (diff) | |
download | ast2050-flashrom-e4edb067a64275ba62669ebb4b42f653cb6aff0d.zip ast2050-flashrom-e4edb067a64275ba62669ebb4b42f653cb6aff0d.tar.gz |
Ignore RES (1 byte) if chip replied to REMS (2 bytes)
SPI RES is the most unreliable way to identify chips because it only
returns a 1-byte ID for most chips.
For every given ID out there, probably a dozen incompatible flash
chips match it. We already refuse to identify a chip with RES if that
chip responds to RDID (3 bytes, good match), and with this patch we
additionally refuse RES if the chip responds to REMS (2 bytes, still a
good match). This increases matching accuracy a lot.
Besides that, the RDID/REMS response checking has been cleaned up for
better readability.
Corresponding to flashrom svn r899.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Sean Nelson <audiohacked@gmail.com>
Diffstat (limited to 'spi.c')
-rw-r--r-- | spi.c | 21 |
1 files changed, 17 insertions, 4 deletions
@@ -385,17 +385,30 @@ int probe_spi_res(struct flashchip *flash) { unsigned char readarr[3]; uint32_t id2; + const unsigned char allff[] = {0xff, 0xff, 0xff}; + const unsigned char all00[] = {0x00, 0x00, 0x00}; - /* Check if RDID was successful and did not return 0xff 0xff 0xff. - * In that case, RES is pointless. + /* Check if RDID is usable and does not return 0xff 0xff 0xff or + * 0x00 0x00 0x00. In that case, RES is pointless. */ - if (!spi_rdid(readarr, 3) && ((readarr[0] != 0xff) || - (readarr[1] != 0xff) || (readarr[2] != 0xff))) + if (!spi_rdid(readarr, 3) && memcmp(readarr, allff, 3) && + memcmp(readarr, all00, 3)) { + msg_cdbg("Ignoring RES in favour of RDID.\n"); return 0; + } + /* Check if REMS is usable and does not return 0xff 0xff or + * 0x00 0x00. In that case, RES is pointless. + */ + if (!spi_rems(readarr) && memcmp(readarr, allff, JEDEC_REMS_INSIZE) && + memcmp(readarr, all00, JEDEC_REMS_INSIZE)) { + msg_cdbg("Ignoring RES in favour of REMS.\n"); + return 0; + } if (spi_res(readarr)) return 0; + /* FIXME: Handle the case where RES gives a 2-byte response. */ id2 = readarr[0]; printf_debug("%s: id 0x%x\n", __func__, id2); if (id2 != flash->model_id) |