From: Matthias Fend <matthias.fend@wolfvision.net>
To: linux-arm-kernel@lists.infradead.org
Cc: dmaengine@vger.kernel.org,
Matthias Fend <matthias.fend@wolfvision.net>,
vkoul@kernel.org, michal.simek@xilinx.com
Subject: [PATCH] dmaengine: zynqmp_dma: fix burst length configuration
Date: Fri, 10 Jan 2020 09:26:07 +0100 [thread overview]
Message-ID: <20200110082607.25353-1-matthias.fend@wolfvision.net> (raw)
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>
---
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 9c845c07b107..aa4de6c6688a 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -123,10 +123,12 @@
/* Max transfer size per descriptor */
#define ZYNQMP_DMA_MAX_TRANS_LEN 0x40000000
+/* Max burst lengths */
+#define ZYNQMP_DMA_MAX_DST_BURST_LEN 16
+#define ZYNQMP_DMA_MAX_SRC_BURST_LEN 16
+
/* 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
@@ -534,17 +536,19 @@ 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);
+ 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);
writel(val, chan->regs + ZYNQMP_DMA_DATA_ATTR);
}
@@ -560,8 +564,10 @@ 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,
+ (u32) ZYNQMP_DMA_MAX_SRC_BURST_LEN);
+ chan->dst_burst_len = clamp(config->dst_maxburst, 1U,
+ (u32) ZYNQMP_DMA_MAX_DST_BURST_LEN);
return 0;
}
@@ -887,8 +893,8 @@ 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");
--
2.17.1
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next reply other threads:[~2020-01-10 8:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 8:26 Matthias Fend [this message]
2020-01-10 8:48 ` [PATCH] dmaengine: zynqmp_dma: fix burst length configuration Michal Simek
2020-01-15 5:41 ` Harini Katakam
2020-01-21 9:18 ` Vinod Koul
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