From: Zhenfang Wang <zhenfang.wang@xxxxxxxxxx>
We will set the link-list pointer register point to next link-list
configuration's physical address, which can load DMA configuration
from the link-list node automatically.
But the link-list node's physical address can be larger than 32bits,
and now Spreadtrum DMA driver only supports 32bits physical address,
which may cause loading a incorrect DMA configuration when starting
the link-list transfer mode. According to the DMA datasheet, we can
use SRC_BLK_STEP register (bit28 - bit31) to save the high bits of the
link-list node's physical address to fix this issue.
Fixes: 4ac695464763 ("dmaengine: sprd: Support DMA link-list mode")
Signed-off-by: Zhenfang Wang <zhenfang.wang@xxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
drivers/dma/sprd-dma.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 525dc73..a4a91f2 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -134,6 +134,10 @@
#define SPRD_DMA_SRC_TRSF_STEP_OFFSET 0
#define SPRD_DMA_TRSF_STEP_MASK GENMASK(15, 0)
+/* SPRD DMA_SRC_BLK_STEP register definition */
+#define SPRD_DMA_LLIST_HIGH_MASK GENMASK(31, 28)
+#define SPRD_DMA_LLIST_HIGH_SHIFT 28
+
/* define DMA channel mode & trigger mode mask */
#define SPRD_DMA_CHN_MODE_MASK GENMASK(7, 0)
#define SPRD_DMA_TRG_MODE_MASK GENMASK(7, 0)
@@ -717,6 +721,7 @@ static int sprd_dma_fill_desc(struct dma_chan *chan,
u32 int_mode = flags & SPRD_DMA_INT_MASK;
int src_datawidth, dst_datawidth, src_step, dst_step;
u32 temp, fix_mode = 0, fix_en = 0;
+ phys_addr_t llist_ptr;
if (dir == DMA_MEM_TO_DEV) {
src_step = sprd_dma_get_step(slave_cfg->src_addr_width);
@@ -814,13 +819,16 @@ static int sprd_dma_fill_desc(struct dma_chan *chan,
* Set the link-list pointer point to next link-list
* configuration's physical address.
*/
- hw->llist_ptr = schan->linklist.phy_addr + temp;
+ llist_ptr = schan->linklist.phy_addr + temp;
+ hw->llist_ptr = lower_32_bits(llist_ptr);
+ hw->src_blk_step = (upper_32_bits(llist_ptr) << SPRD_DMA_LLIST_HIGH_SHIFT) &
+ SPRD_DMA_LLIST_HIGH_MASK;
} else {
hw->llist_ptr = 0;
+ hw->src_blk_step = 0;
}
hw->frg_step = 0;
- hw->src_blk_step = 0;
hw->des_blk_step = 0;
return 0;
}
--
1.7.9.5
