From: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
AXI-DMA IP supports configurable (c_sg_length_width) buffer length
register width, hence read buffer length (xlnx,sg-length-width) DT
property and ensure that driver doesn't program buffer length
exceeding the supported limit. For VDMA and CDMA there is no change.
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Signed-off-by: Andrea Merello <andrea.merello@xxxxxxxxx> [rebase, reword]
---
Changes in v2:
- drop original patch and replace with the one in Xilinx tree
Changes in v3:
- cc DT maintainers/ML
Changes in v4:
- upper bound for the property should be 26, not 23
- add warn for width > 23 as per xilinx original patch
- rework due to changes introduced in 1/6
Changes in v5:
None
Changes in v6:
None
---
drivers/dma/xilinx/xilinx_dma.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index cbf34dd5e966..0716db61f1d0 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -161,7 +161,9 @@
#define XILINX_DMA_REG_BTT 0x28
/* AXI DMA Specific Masks/Bit fields */
-#define XILINX_DMA_MAX_TRANS_LEN GENMASK(22, 0)
+#define XILINX_DMA_MAX_TRANS_LEN_MIN 8
+#define XILINX_DMA_MAX_TRANS_LEN_MAX 23
+#define XILINX_DMA_V2_MAX_TRANS_LEN_MAX 26
#define XILINX_DMA_CR_COALESCE_MAX GENMASK(23, 16)
#define XILINX_DMA_CR_CYCLIC_BD_EN_MASK BIT(4)
#define XILINX_DMA_CR_COALESCE_SHIFT 16
@@ -2622,7 +2624,7 @@ static int xilinx_dma_probe(struct platform_device *pdev)
struct xilinx_dma_device *xdev;
struct device_node *child, *np = pdev->dev.of_node;
struct resource *io;
- u32 num_frames, addr_width;
+ u32 num_frames, addr_width, len_width;
int i, err;
/* Allocate and initialize the DMA engine structure */
@@ -2654,10 +2656,24 @@ static int xilinx_dma_probe(struct platform_device *pdev)
/* Retrieve the DMA engine properties from the device tree */
xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
- xdev->max_buffer_len = XILINX_DMA_MAX_TRANS_LEN;
+ xdev->max_buffer_len = GENMASK(XILINX_DMA_MAX_TRANS_LEN_MAX - 1, 0);
- if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA)
+ if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) {
xdev->mcdma = of_property_read_bool(node, "xlnx,mcdma");
+ if (!of_property_read_u32(node, "xlnx,sg-length-width",
+ &len_width)) {
+ if (len_width < XILINX_DMA_MAX_TRANS_LEN_MIN ||
+ len_width > XILINX_DMA_V2_MAX_TRANS_LEN_MAX) {
+ dev_warn(xdev->dev,
+ "invalid xlnx,sg-length-width property value. Using default width\n");
+ } else {
+ if (len_width > XILINX_DMA_MAX_TRANS_LEN_MAX)
+ dev_warn(xdev->dev, "Please ensure that IP supports buffer length > 23 bits\n");
+ xdev->max_buffer_len =
+ GENMASK(len_width - 1, 0);
+ }
+ }
+ }
if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
err = of_property_read_u32(node, "xlnx,num-fstores",
--
2.17.1
