From 8371d7238a404fb9713c2ff4a011263709c38c34 Mon Sep 17 00:00:00 2001 From: Michael Karcher Date: Tue, 6 Mar 2012 22:17:06 +0000 Subject: Prevent submission of empty read requests in linux_spi The submission of zero-sized read requests in a write-only transaction fails at least for omap2_mcspi drivers and is pointless in general. This patch does not address the implementation of zero-sized writes (which would need to skip the write command), as there are no flash transactions not starting with a command. Corresponding to flashrom svn r1513. Signed-off-by: Michael Karcher Acked-by: Stefan Tauner --- linux_spi.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'linux_spi.c') diff --git a/linux_spi.c b/linux_spi.c index 2ae681f..17d003e 100644 --- a/linux_spi.c +++ b/linux_spi.c @@ -130,6 +130,7 @@ static int linux_spi_send_command(struct flashctx *flash, unsigned int writecnt, const unsigned char *txbuf, unsigned char *rxbuf) { + int iocontrol_code; struct spi_ioc_transfer msg[2] = { { .tx_buf = (uint64_t)(ptrdiff_t)txbuf, @@ -143,8 +144,19 @@ static int linux_spi_send_command(struct flashctx *flash, unsigned int writecnt, if (fd == -1) return -1; - - if (ioctl(fd, SPI_IOC_MESSAGE(2), msg) == -1) { + /* The implementation currently does not support requests that + don't start with sending a command. */ + if (writecnt == 0) + return SPI_INVALID_LENGTH; + + /* Just submit the first (write) request in case there is nothing + to read. Otherwise submit both requests. */ + if (readcnt == 0) + iocontrol_code = SPI_IOC_MESSAGE(1); + else + iocontrol_code = SPI_IOC_MESSAGE(2); + + if (ioctl(fd, iocontrol_code, msg) == -1) { msg_cerr("%s: ioctl: %s\n", __func__, strerror(errno)); return -1; } -- cgit v1.1