There is no need to store the DREQ channel additionally in the channel
structure. This information is already stored in struct dma_slave_config
which is setup by bcm2835_dma_xlate.
Signed-off-by: Alexander Stein <alexanders83@xxxxxx>
---
I compared this driver with the Raspberry Pi foundation kernel and noticed
they set dreq from cfg.slave_id in their bcm2835_dma_prep_slave_sg.
Finding out why they do, I come to the conclusion the channel ID in slave_id
and dreq must be the same each time, even after bcm2835_dma_slave_config has
been called, AFAICS the only position c->cfg is set.
So we can remove the redundant storage.
drivers/dma/bcm2835-dma.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 0723096..6478dc6 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -68,7 +68,6 @@ struct bcm2835_chan {
struct dma_slave_config cfg;
bool cyclic;
- unsigned int dreq;
int ch;
struct bcm2835_desc *desc;
@@ -415,9 +414,9 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
control_block->info |= sync_type;
/* Setup DREQ channel */
- if (c->dreq != 0)
+ if (c->cfg.slave_id != 0)
control_block->info |=
- BCM2835_DMA_PER_MAP(c->dreq);
+ BCM2835_DMA_PER_MAP(c->cfg.slave_id);
/* Length of a frame */
control_block->length = period_len;
@@ -545,7 +544,7 @@ static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec,
return NULL;
/* Set DREQ from param */
- to_bcm2835_dma_chan(chan)->dreq = spec->args[0];
+ to_bcm2835_dma_chan(chan)->cfg.slave_id = spec->args[0];
return chan;
}
--
2.3.3
--
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