linux-kernel - [PATCH v2 1/2] dmaengine: stm32-mdma: align TLEN and buffer length on burst

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Date:   Wed, 11 Apr 2018 16:44:38 +0200
From:   Pierre-Yves MORDRET <pierre-yves.mordret@...com>
To:     Vinod Koul <vinod.koul@...el.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Dan Williams <dan.j.williams@...el.com>,
        "M'boumba Cedric Madianga" <cedric.madianga@...il.com>,
        <dmaengine@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     Pierre-Yves MORDRET <pierre-yves.mordret@...com>
Subject: [PATCH v2 1/2] 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@...com>
---
  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;
 	}
-- 
2.7.4