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 --- flash.h | 1 + jedec.c | 13 ++++++++++++- spi.c | 4 ++++ 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/flash.h b/flash.h index 67f49c69..37d7dc0c 100644 --- a/flash.h +++ b/flash.h @@ -396,6 +396,7 @@ int it8716f_spi_chip_write(struct flashchip *flash, uint8_t *buf); void it8716f_spi_page_program(int block, uint8_t *buf, uint8_t *bios); /* jedec.c */ +uint8_t oddparity(uint8_t val); void toggle_ready_jedec(volatile uint8_t *dst); void data_polling_jedec(volatile uint8_t *dst, uint8_t data); void unprotect_jedec(volatile uint8_t *bios); diff --git a/jedec.c b/jedec.c index 95887519..e818294f 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; diff --git a/spi.c b/spi.c index 5cfc0521..786d555e 100644 --- a/spi.c +++ b/spi.c @@ -71,8 +71,12 @@ int probe_spi(struct flashchip *flash) uint32_t manuf_id; uint32_t model_id; if (!spi_rdid(readarr)) { + if (!oddparity(readarr[0])) + printf_debug("RDID byte 0 parity violation.\n"); /* Check if this is a continuation vendor ID */ if (readarr[0] == 0x7f) { + if (!oddparity(readarr[1])) + printf_debug("RDID byte 1 parity violation.\n"); manuf_id = (readarr[0] << 8) | readarr[1]; model_id = readarr[2]; } else { -- cgit v1.2.3