Pretty much everybody who used the FT2232 SPI driver in flashrom had problems with incorrect reads from time to time. One reason was that the hardware is pretty timing sensitive even for reads.
The other reason was that the code silently ignored errors. This patch doesn't add any error recovery, but it will emit error messages if FT2232 communication goes wrong. That allows us to track down errors without investing hours in driver debugging.
Jeremy, I'd be very interested in the results of an unmodified flashrom with only this patch applied (read is sufficient). In theory, you should either get a working read or loads of error messages about send_buf/read_buf. If you get no error messages and the image read is still wrong, libftdi doesn't tell us about the problem. Oh, and please try in verbose and normal mode. Maybe there's a difference.
This patch will show up at http://patchwork.coreboot.org/project/flashrom/list/ in a few minutes.
Signed-off-by: Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net
Index: flashrom-ft2232_errorcheck/ft2232_spi.c =================================================================== --- flashrom-ft2232_errorcheck/ft2232_spi.c (Revision 756) +++ flashrom-ft2232_errorcheck/ft2232_spi.c (Arbeitskopie) @@ -198,7 +198,8 @@ { struct ftdi_context *ftdic = &ftdic_context; static unsigned char *buf = NULL; - int i = 0, ret = 0; + /* failed is special. We use bitwise ops, but it is essentially bool. */ + int i = 0, ret = 0, failed = 0;
if (writecnt > 65536 || readcnt > 65536) return SPI_INVALID_LENGTH; @@ -237,6 +238,11 @@ buf[i++] = (readcnt - 1) & 0xff; buf[i++] = ((readcnt - 1) >> 8) & 0xff; ret = send_buf(ftdic, buf, i); + failed = ret; + /* We can't abort here, we still have to deassert CS#. */ + if (ret) + fprintf(stderr, "send_buf failed before read: %i\n", + ret); i = 0; if (ret == 0) { /* @@ -245,6 +251,10 @@ * command. We may be scheduled out etc. */ ret = get_buf(ftdic, readarr, readcnt); + failed |= ret; + /* We can't abort here either. */ + if (ret) + fprintf(stderr, "get_buf failed: %i\n", ret); } }
@@ -252,10 +262,12 @@ buf[i++] = SET_BITS_LOW; buf[i++] = CS_BIT; buf[i++] = 0x0b; - if (send_buf(ftdic, buf, i)) - return -1; + ret = send_buf(ftdic, buf, i); + failed |= ret; + if (ret) + fprintf(stderr, "send_buf failed at end: %i\n", ret);
- return ret; + return failed ? -1 : 0; }
int ft2232_spi_read(struct flashchip *flash, uint8_t *buf, int start, int len)