From: Pierre Yves MORDRET pierre-yves.mordret@st.com
Having 0 in item counter register is valid and stands for a "No or Ended transfer". Therefore valid transfer starts from @+0 to @+0xFFFE leading to unaligned scatter gather at boundary. Thus it's safer to round down this value on its FIFO size (16 Bytes).
Signed-off-by: Pierre-Yves MORDRET pierre-yves.mordret@st.com Signed-off-by: Vinod Koul vinod.koul@intel.com --- drivers/dma/stm32-dma.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index b40486454a2c..05a2974cd2c0 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -38,10 +38,6 @@ #define STM32_DMA_TEI BIT(3) /* Transfer Error Interrupt */ #define STM32_DMA_DMEI BIT(2) /* Direct Mode Error Interrupt */ #define STM32_DMA_FEI BIT(0) /* FIFO Error Interrupt */ -#define STM32_DMA_MASKI (STM32_DMA_TCI \ - | STM32_DMA_TEI \ - | STM32_DMA_DMEI \ - | STM32_DMA_FEI)
/* DMA Stream x Configuration Register */ #define STM32_DMA_SCR(x) (0x0010 + 0x18 * (x)) /* x = 0..7 */ @@ -118,6 +114,13 @@ #define STM32_DMA_FIFO_THRESHOLD_FULL 0x03
#define STM32_DMA_MAX_DATA_ITEMS 0xffff +/* + * Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter + * gather at boundary. Thus it's safer to round down this value on FIFO + * size (16 Bytes) + */ +#define STM32_DMA_ALIGNED_MAX_DATA_ITEMS \ + ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16) #define STM32_DMA_MAX_CHANNELS 0x08 #define STM32_DMA_MAX_REQUEST_ID 0x08 #define STM32_DMA_MAX_DATA_PARAM 0x03 @@ -869,7 +872,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( desc->sg_req[i].len = sg_dma_len(sg);
nb_data_items = desc->sg_req[i].len / buswidth; - if (nb_data_items > STM32_DMA_MAX_DATA_ITEMS) { + if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) { dev_err(chan2dev(chan), "nb items not supported\n"); goto err; } @@ -935,7 +938,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( return NULL;
nb_data_items = period_len / buswidth; - if (nb_data_items > STM32_DMA_MAX_DATA_ITEMS) { + if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) { dev_err(chan2dev(chan), "number of items not supported\n"); return NULL; } @@ -985,7 +988,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( u32 num_sgs, best_burst, dma_burst, threshold; int i;
- num_sgs = DIV_ROUND_UP(len, STM32_DMA_MAX_DATA_ITEMS); + num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS); desc = stm32_dma_alloc_desc(num_sgs); if (!desc) return NULL; @@ -994,7 +997,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) { xfer_count = min_t(size_t, len - offset, - STM32_DMA_MAX_DATA_ITEMS); + STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
/* Compute best burst size */ max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;