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From c3cc058594dc78b27132d81378f885e4e4ed51a0 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Wed, 1 Jul 2020 20:28:27 +0100
Subject: [PATCH] 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>
---
drivers/dma/bcm2835-dma.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- 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 *b
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 *b
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 *b
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;
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