On 11/04/18 15:44, Pierre-Yves MORDRET wrote:
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: --- --- drivers/dma/stm32-mdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index daa1602..fbcffa2 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -413,7 +413,7 @@ static u32 stm32_mdma_get_best_burst(u32 buf_len, u32 tlen, u32 max_burst, u32 best_burst = max_burst; u32 burst_len = best_burst * width;- while ((burst_len > 0) && (tlen % burst_len)) {+ while ((burst_len > 0) && (((tlen | buf_len) & (burst_len - 1)) != 0)) { best_burst = best_burst >> 1; burst_len = best_burst * width; }
FWIW, doesn't that whole loop come down to just: burst_len = min(ffs(tlen | buf_len), max_burst * width); ? Robin. -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
