spi_bfin5xx: use PIO for full duplex, not DMA

Use PIO for full-duplex transfers, instead of DMA.

Signed-off-by: Vitja Makarov <vitja.makarov@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index a9ac1fdb3094..7fea3cf4588a 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -608,6 +608,7 @@ static void pump_transfers(unsigned long data)
         u8 width;
         u16 cr, dma_width, dma_config;
         u32 tranf_success = 1;
+        u8 full_duplex = 0;
 
         /* Get current state information */
         message = drv_data->cur_msg;
@@ -658,6 +659,7 @@ static void pump_transfers(unsigned long data)
         }
 
         if (transfer->rx_buf != NULL) {
+                full_duplex = transfer->tx_buf != NULL;
                 drv_data->rx = transfer->rx_buf;
                 drv_data->rx_end = drv_data->rx + transfer->len;
                 dev_dbg(&drv_data->pdev->dev, "rx_buf is %p, rx_end is %p\n",
@@ -740,7 +742,8 @@ static void pump_transfers(unsigned long data)
          * successful use different way to r/w according to
          * drv_data->cur_chip->enable_dma
          */
-        if (drv_data->cur_chip->enable_dma && drv_data->len > 6) {
+        if (!full_duplex && drv_data->cur_chip->enable_dma
+                                && drv_data->len > 6) {
 
                 disable_dma(drv_data->dma_channel);
                 clear_dma_irqstat(drv_data->dma_channel);
@@ -828,7 +831,7 @@ static void pump_transfers(unsigned long data)
                 /* IO mode write then read */
                 dev_dbg(&drv_data->pdev->dev, "doing IO transfer\n");
 
-                if (drv_data->tx != NULL && drv_data->rx != NULL) {
+                if (full_duplex) {
                         /* full duplex mode */
                         BUG_ON((drv_data->tx_end - drv_data->tx) !=
                                (drv_data->rx_end - drv_data->rx));