1 files changed, 16 insertions, 10 deletions

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index b797ece0b10c..88dee87fc420 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -761,11 +761,10 @@ static void pump_transfers(unsigned long data)
         if (!full_duplex && drv_data->cur_chip->enable_dma
                                 && drv_data->len > 6) {
 
-                unsigned long dma_start_addr;
+                unsigned long dma_start_addr, flags;
 
                 disable_dma(drv_data->dma_channel);
                 clear_dma_irqstat(drv_data->dma_channel);
-                bfin_spi_disable(drv_data);
 
                 /* config dma channel */
                 dev_dbg(&drv_data->pdev->dev, "doing dma transfer\n");
@@ -796,8 +795,7 @@ static void pump_transfers(unsigned long data)
                         enable_dma(drv_data->dma_channel);
 
                         /* start SPI transfer */
-                        write_CTRL(drv_data,
-                                (cr | BIT_CTL_TIMOD_DMA_TX | BIT_CTL_ENABLE));
+                        write_CTRL(drv_data, cr | BIT_CTL_TIMOD_DMA_TX);
 
                         /* just return here, there can only be one transfer
                          * in this mode
@@ -842,14 +840,22 @@ static void pump_transfers(unsigned long data)
                 } else
                         BUG();
 
-                /* start dma */
-                dma_enable_irq(drv_data->dma_channel);
-                set_dma_config(drv_data->dma_channel, dma_config);
+                /* oh man, here there be monsters ... and i dont mean the
+                 * fluffy cute ones from pixar, i mean the kind that'll eat
+                 * your data, kick your dog, and love it all.  do *not* try
+                 * and change these lines unless you (1) heavily test DMA
+                 * with SPI flashes on a loaded system (e.g. ping floods),
+                 * (2) know just how broken the DMA engine interaction with
+                 * the SPI peripheral is, and (3) have someone else to blame
+                 * when you screw it all up anyways.
+                 */
                 set_dma_start_addr(drv_data->dma_channel, dma_start_addr);
+                set_dma_config(drv_data->dma_channel, dma_config);
+                local_irq_save(flags);
                 enable_dma(drv_data->dma_channel);
-
-                /* start SPI transfer */
-                write_CTRL(drv_data, (cr | BIT_CTL_ENABLE));
+                write_CTRL(drv_data, cr);
+                dma_enable_irq(drv_data->dma_channel);
+                local_irq_restore(flags);
 
         } else {
                 /* IO mode write then read */