Both buffer Transfer Length (TLEN if any) and transfer size have to be
aligned on burst size (burst beats*bus width).
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@xxxxxx>
---
Version history:
v1:
* Initial
v2:
v3:
* Get rid of while loop in favor of computed values
---
---
drivers/dma/stm32-mdma.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index daa1602..4c7634c 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -410,13 +410,10 @@ static enum dma_slave_buswidth stm32_mdma_get_max_width(dma_addr_t addr,
static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst,
enum dma_slave_buswidth width)
{
- u32 best_burst = max_burst;
- u32 burst_len = best_burst * width;
+ u32 best_burst;
- while ((burst_len > 0) && (tlen % burst_len)) {
- best_burst = best_burst >> 1;
- burst_len = best_burst * width;
- }
+ best_burst = min((u32)1 << __ffs(tlen | buf_len),
+ max_burst * width) / width;
return (best_burst > 0) ? best_burst : 1;
}
--
2.7.4
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