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>
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index a9ac1fd..7fea3cf 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -608,6 +608,7 @@
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 @@
}
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 @@
* 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 @@
/* 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));