AT91/AVR32: atmel_spi.c: flush RDR before next SPI transaction
Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 317c0b4..d0de931 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -43,7 +43,7 @@
u32 csrx;
void *regs;
- if (cs > 3 || !spi_cs_is_valid(bus, cs))
+ if (!spi_cs_is_valid(bus, cs))
return NULL;
switch (bus) {
@@ -168,8 +168,17 @@
* somewhat quirky, and it doesn't really buy us much anyway
* in the context of U-Boot.
*/
- if (flags & SPI_XFER_BEGIN)
+ if (flags & SPI_XFER_BEGIN) {
spi_cs_activate(slave);
+ /*
+ * sometimes the RDR is not empty when we get here,
+ * in theory that should not happen, but it DOES happen.
+ * Read it here to be on the safe side.
+ * That also clears the OVRES flag. Required if the
+ * following loop exits due to OVRES!
+ */
+ spi_readl(as, RDR);
+ }
for (len_tx = 0, len_rx = 0; len_rx < len; ) {
status = spi_readl(as, SR);