From a2441cef65161f5d5b4b7a80de8379173a0d04cc Mon Sep 17 00:00:00 2001 From: Carl-Daniel Hailfinger Date: Sun, 22 Nov 2009 01:33:40 +0000 Subject: ft2232_spi: add some error handling Pretty much everybody who used the FT2232 SPI driver 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. Thanks to Jeremy Buseman for testing. He found out that certain libftdi/libusb/kernel/hardware combinations drop some bytes without returning any error codes. Corresponding to flashrom svn r769. Signed-off-by: Carl-Daniel Hailfinger Acked-by: Paul Fox --- ft2232_spi.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/ft2232_spi.c b/ft2232_spi.c index 17930ebe..aa007533 100644 --- a/ft2232_spi.c +++ b/ft2232_spi.c @@ -198,7 +198,8 @@ int ft2232_spi_send_command(unsigned int writecnt, unsigned int readcnt, { 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 @@ int ft2232_spi_send_command(unsigned int writecnt, unsigned int readcnt, 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 @@ int ft2232_spi_send_command(unsigned int writecnt, unsigned int readcnt, * 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 @@ int ft2232_spi_send_command(unsigned int writecnt, unsigned int readcnt, 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) -- cgit v1.2.3