From: Pierre-Yves MORDRET pierre-yves.mordret@st.com
commit cc832dc8e32785a730ba07c3a357e17c201a5df8 upstream.
When a period length is not multiple of FIFO some data may be stuck within FIFO.
Burst/FIFO Threshold/Period or buffer length check has to be hardened
In any case DMA will grant any request from client but will degraded any parameters whether awkward.
Signed-off-by: Pierre-Yves MORDRET pierre-yves.mordret@st.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/dma/stm32-dma.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-)
--- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -308,20 +308,12 @@ static bool stm32_dma_fifo_threshold_is_
static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold) { - switch (threshold) { - case STM32_DMA_FIFO_THRESHOLD_FULL: - if (buf_len >= STM32_DMA_MAX_BURST) - return true; - else - return false; - case STM32_DMA_FIFO_THRESHOLD_HALFFULL: - if (buf_len >= STM32_DMA_MAX_BURST / 2) - return true; - else - return false; - default: - return false; - } + /* + * Buffer or period length has to be aligned on FIFO depth. + * Otherwise bytes may be stuck within FIFO at buffer or period + * length. + */ + return ((buf_len % ((threshold + 1) * 4)) == 0); }
static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,