[PATCH v3 4/5] dmaengine: xilinx_dma: autodetect whether the HW supports scatter-gather
From: vkoul@kernel.org (Vinod)
Date: 2018-06-29 07:37:21
Also in:
dmaengine, linux-devicetree, lkml
On 25-06-18, 11:27, Andrea Merello wrote:
The AXIDMA and CDMA HW can be either direct-access or scatter-gather version. These are SW incompatible. The driver can handle both version: a DT property was used to
^^^^ versions
tell the driver whether to assume the HW is is scatter-gather mode.
^^^^^ is in?
quoted hunk ↗ jump to hunk
This patch makes the driver to autodetect this information. The DT property is not required anymore. No changes for VDMA. Cc: Rob Herring <robh+dt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree at vger.kernel.org Cc: Radhey Shyam Pandey <redacted> Signed-off-by: Andrea Merello <redacted> Reviewed-by: Radhey Shyam Pandey <redacted> --- Changes in v2: - autodetect only in !VDMA case Changes in v3: - cc DT maintainers/ML --- drivers/dma/xilinx/xilinx_dma.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 7f0ab904b749..43fcc71ff287 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c@@ -86,6 +86,7 @@ #define XILINX_DMA_DMASR_DMA_DEC_ERR BIT(6) #define XILINX_DMA_DMASR_DMA_SLAVE_ERR BIT(5) #define XILINX_DMA_DMASR_DMA_INT_ERR BIT(4) +#define XILINX_DMA_DMASR_SG_MASK BIT(3) #define XILINX_DMA_DMASR_IDLE BIT(1) #define XILINX_DMA_DMASR_HALTED BIT(0) #define XILINX_DMA_DMASR_DELAY_MASK GENMASK(31, 24)@@ -406,7 +407,6 @@ struct xilinx_dma_config { * @dev: Device Structure * @common: DMA device structure * @chan: Driver specific DMA channel - * @has_sg: Specifies whether Scatter-Gather is present or not * @mcdma: Specifies whether Multi-Channel is present or not * @flush_on_fsync: Flush on frame sync * @ext_addr: Indicates 64 bit addressing is supported by dma device@@ -426,7 +426,6 @@ struct xilinx_dma_device { struct device *dev; struct dma_device common; struct xilinx_dma_chan *chan[XILINX_DMA_MAX_CHANS_PER_DEVICE]; - bool has_sg; bool mcdma; u32 flush_on_fsync; bool ext_addr;@@ -2393,7 +2392,6 @@ static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev, chan->dev = xdev->dev; chan->xdev = xdev; - chan->has_sg = xdev->has_sg; chan->desc_pendingcount = 0x0; chan->ext_addr = xdev->ext_addr; /* This variable ensures that descriptors are not@@ -2486,6 +2484,15 @@ static int xilinx_dma_chan_probe(struct xilinx_dma_device *xdev, chan->stop_transfer = xilinx_dma_stop_transfer; } + /* check if SG is enabled (only for AXIDMA and CDMA) */ + if (xdev->dma_config->dmatype != XDMA_TYPE_VDMA) { + if (dma_ctrl_read(chan, XILINX_DMA_REG_DMASR) & + XILINX_DMA_DMASR_SG_MASK)
why not read this for VDMA too, will it return false?
+ chan->has_sg = true; + dev_dbg(chan->dev, "ch %d: SG %s\n", chan->id, + chan->has_sg ? "enabled" : "disabled");
this debug print can be removed -- ~Vinod