bcm2835-dma: Add NO_WAIT_RESP flag

Use bit 27 of the dreq value (the second cell of the DT DMA descriptor)
to request that the WAIT_RESP bit is not set.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index ac0458a..84b1009 100644 (file)
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -165,6 +165,11 @@ struct bcm2835_desc {
 #define BCM2835_DMA_WAIT(x)    ((x & 31) << 21) /* add DMA-wait cycles */
 #define BCM2835_DMA_NO_WIDE_BURSTS BIT(26) /* no 2 beat write bursts */
 
+/* A fake bit to request that the driver doesn't set the WAIT_RESP bit. */
+#define BCM2835_DMA_NO_WAIT_RESP BIT(27)
+#define WAIT_RESP(x) ((x & BCM2835_DMA_NO_WAIT_RESP) ? \
+                     0 : BCM2835_DMA_WAIT_RESP)
+
 /* debug register bits */
 #define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR     BIT(0)
 #define BCM2835_DMA_DEBUG_FIFO_ERR             BIT(1)
@@ -843,7 +848,7 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy(
        struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
        struct bcm2835_desc *d;
        u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC;
-       u32 extra = BCM2835_DMA_INT_EN | BCM2835_DMA_WAIT_RESP;
+       u32 extra = BCM2835_DMA_INT_EN | WAIT_RESP(c->dreq);
        size_t max_len = bcm2835_dma_max_frame_length(c);
        size_t frames;
 
@@ -873,7 +878,7 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
        struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
        struct bcm2835_desc *d;
        dma_addr_t src = 0, dst = 0;
-       u32 info = BCM2835_DMA_WAIT_RESP;
+       u32 info = WAIT_RESP(c->dreq);
        u32 extra = BCM2835_DMA_INT_EN;
        size_t frames;
 
@@ -935,7 +940,7 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
        struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
        struct bcm2835_desc *d;
        dma_addr_t src, dst;
-       u32 info = BCM2835_DMA_WAIT_RESP;
+       u32 info = WAIT_RESP(c->dreq);
        u32 extra = 0;
        size_t max_len = bcm2835_dma_max_frame_length(c);
        size_t frames;