[PATCH AUTOSEL 4.14 030/127] dmaengine: zynqmp_dma: fix burst length configuration

Sasha Levin
2020-09-18T02:12:59Z

From: Matthias Fend <matthias.fend@wolfvision.net>

[ Upstream commit cc88525ebffc757e00cc5a5d61da6271646c7f5f ]

Since the dma engine expects the burst length register content as
power of 2 value, the burst length needs to be converted first.
Additionally add a burst length range check to avoid corrupting unrelated
register bits.

Signed-off-by: Matthias Fend <matthias.fend@wolfvision.net>
Link: https://lore.kernel.org/r/20200115102249.24398-1-matthias.fend@wolfvision.net
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/xilinx/zynqmp_dma.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 6d86d05e53aa1..66d6640766ed8 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -125,10 +125,12 @@
/* Max transfer size per descriptor */
#define ZYNQMP_DMA_MAX_TRANS_LEN 0x40000000

+/* Max burst lengths */
+#define ZYNQMP_DMA_MAX_DST_BURST_LEN 32768U
+#define ZYNQMP_DMA_MAX_SRC_BURST_LEN 32768U
+
/* Reset values for data attributes */
#define ZYNQMP_DMA_AXCACHE_VAL 0xF
-#define ZYNQMP_DMA_ARLEN_RST_VAL 0xF
-#define ZYNQMP_DMA_AWLEN_RST_VAL 0xF

#define ZYNQMP_DMA_SRC_ISSUE_RST_VAL 0x1F

@@ -527,17 +529,19 @@ static void zynqmp_dma_handle_ovfl_int(struct zynqmp_dma_chan *chan, u32 status)

static void zynqmp_dma_config(struct zynqmp_dma_chan *chan)
{
- u32 val;
+ u32 val, burst_val;

val = readl(chan->regs + ZYNQMP_DMA_CTRL0);
val |= ZYNQMP_DMA_POINT_TYPE_SG;
writel(val, chan->regs + ZYNQMP_DMA_CTRL0);

val = readl(chan->regs + ZYNQMP_DMA_DATA_ATTR);
+ burst_val = __ilog2_u32(chan->src_burst_len);
val = (val & ~ZYNQMP_DMA_ARLEN) |
- (chan->src_burst_len << ZYNQMP_DMA_ARLEN_OFST);
+ ((burst_val << ZYNQMP_DMA_ARLEN_OFST) & ZYNQMP_DMA_ARLEN);
+ burst_val = __ilog2_u32(chan->dst_burst_len);
val = (val & ~ZYNQMP_DMA_AWLEN) |
- (chan->dst_burst_len << ZYNQMP_DMA_AWLEN_OFST);
+ ((burst_val << ZYNQMP_DMA_AWLEN_OFST) & ZYNQMP_DMA_AWLEN);
writel(val, chan->regs + ZYNQMP_DMA_DATA_ATTR);
}

@@ -551,8 +555,10 @@ static int zynqmp_dma_device_config(struct dma_chan *dchan,
{
struct zynqmp_dma_chan *chan = to_chan(dchan);

- chan->src_burst_len = config->src_maxburst;
- chan->dst_burst_len = config->dst_maxburst;
+ chan->src_burst_len = clamp(config->src_maxburst, 1U,
+ ZYNQMP_DMA_MAX_SRC_BURST_LEN);
+ chan->dst_burst_len = clamp(config->dst_maxburst, 1U,
+ ZYNQMP_DMA_MAX_DST_BURST_LEN);

return 0;
}
@@ -873,8 +879,8 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
return PTR_ERR(chan->regs);

chan->bus_width = ZYNQMP_DMA_BUS_WIDTH_64;
- chan->dst_burst_len = ZYNQMP_DMA_AWLEN_RST_VAL;
- chan->src_burst_len = ZYNQMP_DMA_ARLEN_RST_VAL;
+ chan->dst_burst_len = ZYNQMP_DMA_MAX_DST_BURST_LEN;
+ chan->src_burst_len = ZYNQMP_DMA_MAX_SRC_BURST_LEN;
err = of_property_read_u32(node, "xlnx,bus-width", &chan->bus_width);
if (err < 0) {
dev_err(&pdev->dev, "missing xlnx,bus-width property\n");
--
2.25.1