Changeset 1513 for trunk/linux_spi.c

Timestamp:

Mar 6, 2012 11:17:06 PM (15 months ago)

Author:

mkarcher

Message:

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.

Signed-off-by: Michael Karcher <flashrom@…>
Acked-by: Stefan Tauner <stefan.tauner@…>

File:

• trunk/linux_spi.c (modified) (2 diffs)

trunk/linux_spi.c

@@ -131 +131 @@
                                   unsigned char *rxbuf)
 {
+        int iocontrol_code;
         struct spi_ioc_transfer msg[2] = {
                 {
@@ -144 +145 @@
         if (fd == -1)
                 return -1;
+        /* The implementation currently does not support requests that
+           don't start with sending a command. */
+        if (writecnt == 0)
+                return SPI_INVALID_LENGTH;
 
-        if (ioctl(fd, SPI_IOC_MESSAGE(2), msg) == -1) {
+        /* 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;