spi_mpc83xx: hang fix

When the spi_mpc83xx driver receives a tx_buf pointer which is NULL, it
only writes one zero filled word to the transmit register.  If the driver
expects to receive more than one word it will wait forever for a second
receive interrupt.  With this patch the controller will shift out zeroes
until all words have been received.

Signed-off-by: Jan Andersson <jan@gaisler.com>
Tested-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/spi/spi_mpc83xx.c b/drivers/spi/spi_mpc83xx.c
index fcbf1b8a5264dfec0e4e8f74b6101f5440ea8ea6..32cda77b31cd2c5625bf8c10eeabb88814ede008 100644 (file)
--- a/drivers/spi/spi_mpc83xx.c
+++ b/drivers/spi/spi_mpc83xx.c
@@ -384,11 +384,8 @@ irqreturn_t mpc83xx_spi_irq(s32 irq, void *context_data)
 
        mpc83xx_spi->count -= 1;
        if (mpc83xx_spi->count) {
-               if (mpc83xx_spi->tx) {
-                       u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
-                       mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit,
-                                             word);
-               }
+               u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
+               mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word);
        } else {
                complete(&mpc83xx_spi->done);
        }