Re: [flashrom] [PATCH] Make Bus Pirate init more robust

[Mattias Mattsson]

On Fri, Jul 23, 2010 at 22:52, Carl-Daniel Hailfinger
 wrote:
> Thanks to Johannes Sjölund for reporting that the Bus Pirate init could
> not deal with a Bus Pirate which is already in binary Bitbang mode. This
> is caused by a combination of the slowness of the Bus Pirate, the
> slowness of USB and a fast serial port flush routine which just flushes
> the buffer contents and does not wait until data arrival stops.
>
> Make the Bus Pirate init more robust by running the flush command 10
> times with 1.5 ms delay in between.
>
> This code development was sponsored by Mattias Mattsson. Thanks!
> Tested a few dozen times, should work reliably.
>
> Signed-off-by: Carl-Daniel Hailfinger

Acked-by: Mattias Mattsson
> Index: flashrom-buspirate_resilient_init/buspirate_spi.c
>
> --- flashrom-buspirate_resilient_init/buspirate_spi.c   (Revision 1099)
> +++ flashrom-buspirate_resilient_init/buspirate_spi.c   (Arbeitskopie)
> @@ -22,6 +22,7 @@
>  #include <string.h>
>  #include <stdlib.h>
>  #include <ctype.h>
> +#include <unistd.h>
>  #include "flash.h"
>  #include "chipdrivers.h"
>  #include "spi.h"
> @@ -140,6 +141,20 @@
>                /* Read any response and discard it. */
>                sp_flush_incoming();
>        }
> /* USB is slow. The Bus Pirate is even slower. Apparently the flush
> * action above is too fast or too early. Some stuff still remains in
> * the pipe after the flush above, and one additional flush is not
> * sufficient either. Use a 1.5 ms delay inside the loop to make
> * mostly sure that at least one USB frame had time to arrive.
> * Looping only 5 times is not sufficient and causes the
> * ocassional failure.
> * Folding the delay into the loop above is not reliable either.
> */
> for (i = 0; i < 10; i++) {
> usleep(1500);
> /* Read any response and discard it. */
> sp_flush_incoming();
> }
>
> /* Enter raw bitbang mode */
>        buf[0] = 0x00;
>        ret = buspirate_sendrecv(buf, 1, 5);
> @@ -147,6 +162,8 @@
>                return ret;
>        if (memcmp(buf, "BBIO", 4)) {
>                msg_perr("Entering raw bitbang mode failed!\n");
> msg_pdbg("Got %02x%02x%02x%02x%02x\n",
> buf[0], buf[1], buf[2], buf[3], buf[4]);
>
> return 1;
>        }
>        msg_pdbg("Raw bitbang mode version %c\n", buf[4]);
> @@ -158,8 +175,12 @@
>        /* Enter raw SPI mode */
>        buf[0] = 0x01;
>        ret = buspirate_sendrecv(buf, 1, 4);
> if (ret)
> return ret;
>
> if (memcmp(buf, "SPI", 3)) {
>                msg_perr("Entering raw SPI mode failed!\n");
> msg_pdbg("Got %02x%02x%02x%02x\n",
> buf[0], buf[1], buf[2], buf[3]);
>
> return 1;
>        }
>        msg_pdbg("Raw SPI mode version %c\n", buf[3]);
> Index: flashrom-buspirate_resilient_init/serial.c
> ===================================================================
> --- flashrom-buspirate_resilient_init/serial.c  (Revision 1099)
> +++ flashrom-buspirate_resilient_init/serial.c  (Arbeitskopie)
> @@ -199,8 +199,10 @@
>  #else
>                tmp = write(sp_fd, buf, writecnt);
>  #endif
> if (tmp == -1)
> if (tmp == -1) {
> msg_perr("Serial port write error!\n");
>
> return 1;
> }
>
> if (!tmp)
>                        msg_pdbg("Empty write\n");
>                writecnt -= tmp;
> @@ -220,8 +222,10 @@
>  #else
>                tmp = read(sp_fd, buf, readcnt);
>  #endif
> if (tmp == -1)
> if (tmp == -1) {
> msg_perr("Serial port read error!\n");
>
> return 1;
> }
>
> if (!tmp)
>                        msg_pdbg("Empty read\n");
>                readcnt -= tmp;
>
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