From a758f5100dd6266af29d63302e745b1a3ad89bed Mon Sep 17 00:00:00 2001 From: Carl-Daniel Hailfinger Date: Wed, 14 May 2008 12:03:06 +0000 Subject: Check the JEDEC vendor ID for correct parity Flash chips which can be detected by JEDEC probe routines all have vendor IDs with correct parity. Use a parity check as additional hint whether a vendor ID makes sense. Note: Device IDs have no parity requirements whatsoever. Corresponding to flashrom svn r231 and coreboot v2 svn r3308. Signed-off-by: Carl-Daniel Hailfinger Acked-by: Peter Stuge --- jedec.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'jedec.c') diff --git a/jedec.c b/jedec.c index 9588751..e818294 100644 --- a/jedec.c +++ b/jedec.c @@ -27,6 +27,14 @@ #define MAX_REFLASH_TRIES 0x10 +/* Check one byte for odd parity */ +uint8_t oddparity(uint8_t val) +{ + val = (val ^ (val >> 4)) & 0xf; + val = (val ^ (val >> 2)) & 0x3; + return (val ^ (val >> 1)) & 0x1; +} + void toggle_ready_jedec(volatile uint8_t *dst) { unsigned int i = 0; @@ -123,7 +131,10 @@ int probe_jedec(struct flashchip *flash) *(volatile uint8_t *)(bios + 0x5555) = 0xF0; myusec_delay(40); - printf_debug("%s: id1 0x%x, id2 0x%x\n", __FUNCTION__, largeid1, largeid2); + printf_debug("%s: id1 0x%x, id2 0x%x", __FUNCTION__, largeid1, largeid2); + if (!oddparity(id1)) + printf_debug(", id1 parity violation"); + printf_debug("\n"); if (largeid1 == flash->manufacture_id && largeid2 == flash->model_id) return 1; -- cgit v1.1