Commit 78a2f92e authored by Alexandru Ardelean's avatar Alexandru Ardelean Committed by Vinod Koul
Browse files

dmaengine: axi-dmac: add support for reading bus attributes from registers 



Starting with core version 4.3.a the DMA bus attributes can (and should) be
read from the INTERFACE_DESCRIPTION (0x10) register.

For older core versions, this will still need to be provided from the
device-tree.

The bus-type values are identical to the ones stored in the device-trees,
so we just need to read them. Bus-width values are stored in log2 values,
so we just need to use them as shift values to make them equivalent to the
current format.

Signed-off-by: default avatarAlexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20200825151950.57605-7-alexandru.ardelean@analog.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 3061a65c

drivers/dma/dma-axi-dmac.c

+63 −3
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 *  Author: Lars-Peter Clausen <lars@metafoo.de>

 */



#include <linux/bitfield.h>

#include <linux/clk.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>
@@ -45,6 +46,16 @@ 
 * there is no address than can or needs to be configured for the device side.

 */



#define AXI_DMAC_REG_INTERFACE_DESC	0x10

#define   AXI_DMAC_DMA_SRC_TYPE_MSK	GENMASK(13, 12)

#define   AXI_DMAC_DMA_SRC_TYPE_GET(x)	FIELD_GET(AXI_DMAC_DMA_SRC_TYPE_MSK, x)

#define   AXI_DMAC_DMA_SRC_WIDTH_MSK	GENMASK(11, 8)

#define   AXI_DMAC_DMA_SRC_WIDTH_GET(x)	FIELD_GET(AXI_DMAC_DMA_SRC_WIDTH_MSK, x)

#define   AXI_DMAC_DMA_DST_TYPE_MSK	GENMASK(5, 4)

#define   AXI_DMAC_DMA_DST_TYPE_GET(x)	FIELD_GET(AXI_DMAC_DMA_DST_TYPE_MSK, x)

#define   AXI_DMAC_DMA_DST_WIDTH_MSK	GENMASK(3, 0)

#define   AXI_DMAC_DMA_DST_WIDTH_GET(x)	FIELD_GET(AXI_DMAC_DMA_DST_WIDTH_MSK, x)



#define AXI_DMAC_REG_IRQ_MASK		0x80

#define AXI_DMAC_REG_IRQ_PENDING	0x84

#define AXI_DMAC_REG_IRQ_SOURCE		0x88
@@ -801,6 +812,51 @@ static int axi_dmac_parse_dt(struct device *dev, struct axi_dmac *dmac) 
	return 0;

}



static int axi_dmac_read_chan_config(struct device *dev, struct axi_dmac *dmac)

{

	struct axi_dmac_chan *chan = &dmac->chan;

	unsigned int val, desc;



	desc = axi_dmac_read(dmac, AXI_DMAC_REG_INTERFACE_DESC);

	if (desc == 0) {

		dev_err(dev, "DMA interface register reads zero\n");

		return -EFAULT;

	}



	val = AXI_DMAC_DMA_SRC_TYPE_GET(desc);

	if (val > AXI_DMAC_BUS_TYPE_FIFO) {

		dev_err(dev, "Invalid source bus type read: %d\n", val);

		return -EINVAL;

	}

	chan->src_type = val;



	val = AXI_DMAC_DMA_DST_TYPE_GET(desc);

	if (val > AXI_DMAC_BUS_TYPE_FIFO) {

		dev_err(dev, "Invalid destination bus type read: %d\n", val);

		return -EINVAL;

	}

	chan->dest_type = val;



	val = AXI_DMAC_DMA_SRC_WIDTH_GET(desc);

	if (val == 0) {

		dev_err(dev, "Source bus width is zero\n");

		return -EINVAL;

	}

	/* widths are stored in log2 */

	chan->src_width = 1 << val;



	val = AXI_DMAC_DMA_DST_WIDTH_GET(desc);

	if (val == 0) {

		dev_err(dev, "Destination bus width is zero\n");

		return -EINVAL;

	}

	chan->dest_width = 1 << val;



	axi_dmac_adjust_chan_params(chan);



	return 0;

}



static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)

{

	struct axi_dmac_chan *chan = &dmac->chan;
@@ -880,7 +936,13 @@ static int axi_dmac_probe(struct platform_device *pdev) 
	if (ret < 0)

		return ret;



	version = axi_dmac_read(dmac, ADI_AXI_REG_VERSION);



	if (version >= ADI_AXI_PCORE_VER(4, 3, 'a'))

		ret = axi_dmac_read_chan_config(&pdev->dev, dmac);

	else

		ret = axi_dmac_parse_dt(&pdev->dev, dmac);



	if (ret < 0)

		goto err_clk_disable;
@@ -912,8 +974,6 @@ static int axi_dmac_probe(struct platform_device *pdev) 
	dmac->chan.vchan.desc_free = axi_dmac_desc_free;

	vchan_init(&dmac->chan.vchan, dma_dev);



	version = axi_dmac_read(dmac, ADI_AXI_REG_VERSION);



	ret = axi_dmac_detect_caps(dmac, version);

	if (ret)

		goto err_clk_disable;