diff options
| author | Pierre-Yves MORDRET <pierre-yves.mordret@st.com> | 2018-09-11 09:31:16 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-05 09:21:35 +0100 |
| commit | ecda0abb141725d9d76dcc8b07c78b4506098b73 (patch) | |
| tree | 1068551e2f6e738d1749f7d6b1d448bd5db296e4 | |
| parent | f0b7d56f1fd58b7a45c2ebe06fa96eea68eb2ea3 (diff) | |
dmaengine: stm32-dma: check whether length is aligned on FIFO threshold
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>
| -rw-r--r-- | drivers/dma/stm32-dma.c | 20 |
1 files changed, 6 insertions, 14 deletions
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index 379e8d534e61..4903a408fc14 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -308,20 +308,12 @@ static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold, 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, |