dmaengine: stm32-mdma: align TLEN and buffer length on burst

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@st.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index daa1602..4c7634c 100644 (file)
--- 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;
 }