[RESEND PATCH v2 0/6] dmaengine: axi-dmac: add support for reading bus attributes from register

[RESEND PATCH v2 0/6] dmaengine: axi-dmac: add support for reading bus attributes from register

[Alexandru Ardelean]

The series adds support for reading the DMA bus attributes from the
INTERFACE_DESCRIPTION (0x10) register.

The first 5 changes are a bit of rework prior to adding the actual
change in patch 6, as things need to be shifted around a bit, to enable 
the clock to be enabled earlier, to be able to read the version
register.

Changelog v1 -> v2:
* fixed error-exit paths for the clock move patch
  i.e. 'dmaengine: axi-dmac: move clock enable earlier'
* fixed error-exit path for patch
  'axi-dmac: wrap channel parameter adjust into function'
* added patch 'dmaengine: axi-dmac: move active_descs list init after device-tree init'
  the list of active_descs can be moved a bit lower in the init/probe
*** BLURB HERE ***

Alexandru Ardelean (6):
  dmaengine: axi-dmac: move version read in probe
  dmaengine: axi-dmac: move active_descs list init after device-tree
    init
  dmaengine: axi-dmac: move clock enable earlier
  dmaengine: axi-dmac: wrap entire dt parse in a function
  dmaengine: axi-dmac: wrap channel parameter adjust into function
  dmaengine: axi-dmac: add support for reading bus attributes from
    registers

 drivers/dma/dma-axi-dmac.c | 138 ++++++++++++++++++++++++++++---------
 1 file changed, 107 insertions(+), 31 deletions(-)

-- 
2.17.1

[RESEND PATCH v2 1/6] dmaengine: axi-dmac: move version read in probe

[Alexandru Ardelean]

The 'version' of the IP core will be needed to adapt the driver to a new
feature (i.e. reading some DMA parameters from registers).
To do that, the version will be checked, so this is being moved out of the
axi_dmac_detect_caps() function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index f1d149e32839..088c79137398 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -774,12 +774,9 @@ static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
 	return 0;
 }
 
-static int axi_dmac_detect_caps(struct axi_dmac *dmac)
+static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
 {
 	struct axi_dmac_chan *chan = &dmac->chan;
-	unsigned int version;
-
-	version = axi_dmac_read(dmac, ADI_AXI_REG_VERSION);
 
 	axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, AXI_DMAC_FLAG_CYCLIC);
 	if (axi_dmac_read(dmac, AXI_DMAC_REG_FLAGS) == AXI_DMAC_FLAG_CYCLIC)
@@ -831,6 +828,7 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	struct axi_dmac *dmac;
 	struct resource *res;
 	struct regmap *regmap;
+	unsigned int version;
 	int ret;
 
 	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
@@ -898,7 +896,9 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	ret = axi_dmac_detect_caps(dmac);
+	version = axi_dmac_read(dmac, ADI_AXI_REG_VERSION);
+
+	ret = axi_dmac_detect_caps(dmac, version);
 	if (ret)
 		goto err_clk_disable;
 
-- 
2.17.1

[RESEND PATCH v2 2/6] dmaengine: axi-dmac: move active_descs list init after device-tree init

[Alexandru Ardelean]

We want to enable the clock right after it is obtained. Then later we'll
want to read the core version via register-access (which requires the clock
to be enabled).

The initialization of the active_descs list can be postponed after reading
from registers (or reading the device-tree).

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 088c79137398..90a99bdffa2b 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -850,8 +850,6 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	if (IS_ERR(dmac->clk))
 		return PTR_ERR(dmac->clk);
 
-	INIT_LIST_HEAD(&dmac->chan.active_descs);
-
 	of_channels = of_get_child_by_name(pdev->dev.of_node, "adi,channels");
 	if (of_channels == NULL)
 		return -ENODEV;
@@ -866,6 +864,8 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	}
 	of_node_put(of_channels);
 
+	INIT_LIST_HEAD(&dmac->chan.active_descs);
+
 	pdev->dev.dma_parms = &dmac->dma_parms;
 	dma_set_max_seg_size(&pdev->dev, UINT_MAX);
 
-- 
2.17.1

[RESEND PATCH v2 3/6] dmaengine: axi-dmac: move clock enable earlier

[Alexandru Ardelean]

The clock may also be required to read registers from the IP core (if it is
provided and the driver needs to control it).
So, move it earlier in the probe.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 90a99bdffa2b..f4b17b5e3914 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -850,16 +850,23 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	if (IS_ERR(dmac->clk))
 		return PTR_ERR(dmac->clk);
 
+	ret = clk_prepare_enable(dmac->clk);
+	if (ret < 0)
+		return ret;
+
 	of_channels = of_get_child_by_name(pdev->dev.of_node, "adi,channels");
-	if (of_channels == NULL)
-		return -ENODEV;
+	if (of_channels == NULL) {
+		ret = -ENODEV;
+		goto err_clk_disable;
+	}
 
 	for_each_child_of_node(of_channels, of_chan) {
 		ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
 		if (ret) {
 			of_node_put(of_chan);
 			of_node_put(of_channels);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_clk_disable;
 		}
 	}
 	of_node_put(of_channels);
@@ -892,10 +899,6 @@ 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);
 
-	ret = clk_prepare_enable(dmac->clk);
-	if (ret < 0)
-		return ret;
-
 	version = axi_dmac_read(dmac, ADI_AXI_REG_VERSION);
 
 	ret = axi_dmac_detect_caps(dmac, version);
-- 
2.17.1

[RESEND PATCH v2 4/6] dmaengine: axi-dmac: wrap entire dt parse in a function

[Alexandru Ardelean]

All these attributes will be read from registers in newer core versions, so
just wrap the logic into a function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 40 +++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index f4b17b5e3914..1a1e227fa935 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -774,6 +774,28 @@ static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
 	return 0;
 }
 
+static int axi_dmac_parse_dt(struct device *dev, struct axi_dmac *dmac)
+{
+	struct device_node *of_channels, *of_chan;
+	int ret;
+
+	of_channels = of_get_child_by_name(dev->of_node, "adi,channels");
+	if (of_channels == NULL)
+		return -ENODEV;
+
+	for_each_child_of_node(of_channels, of_chan) {
+		ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
+		if (ret) {
+			of_node_put(of_chan);
+			of_node_put(of_channels);
+			return -EINVAL;
+		}
+	}
+	of_node_put(of_channels);
+
+	return 0;
+}
+
 static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
 {
 	struct axi_dmac_chan *chan = &dmac->chan;
@@ -823,7 +845,6 @@ static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
 
 static int axi_dmac_probe(struct platform_device *pdev)
 {
-	struct device_node *of_channels, *of_chan;
 	struct dma_device *dma_dev;
 	struct axi_dmac *dmac;
 	struct resource *res;
@@ -854,22 +875,9 @@ static int axi_dmac_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	of_channels = of_get_child_by_name(pdev->dev.of_node, "adi,channels");
-	if (of_channels == NULL) {
-		ret = -ENODEV;
+	ret = axi_dmac_parse_dt(&pdev->dev, dmac);
+	if (ret < 0)
 		goto err_clk_disable;
-	}
-
-	for_each_child_of_node(of_channels, of_chan) {
-		ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
-		if (ret) {
-			of_node_put(of_chan);
-			of_node_put(of_channels);
-			ret = -EINVAL;
-			goto err_clk_disable;
-		}
-	}
-	of_node_put(of_channels);
 
 	INIT_LIST_HEAD(&dmac->chan.active_descs);
 
-- 
2.17.1

[RESEND PATCH v2 5/6] dmaengine: axi-dmac: wrap channel parameter adjust into function

[Alexandru Ardelean]

The channel parameters (which are read from the device-tree) are adjusted
for the DMAEngine framework in the axi_dmac_parse_chan_dt() function, after
they are read from the device-tree.

When we want to read these from registers, we will need to use the same
logic, so this change splits the logic into a separate function.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 1a1e227fa935..7ee56ae60093 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -717,6 +717,20 @@ static const struct regmap_config axi_dmac_regmap_config = {
 	.writeable_reg = axi_dmac_regmap_rdwr,
 };
 
+static void axi_dmac_adjust_chan_params(struct axi_dmac_chan *chan)
+{
+	chan->address_align_mask = max(chan->dest_width, chan->src_width) - 1;
+
+	if (axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_MEM_TO_MEM;
+	else if (!axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_MEM_TO_DEV;
+	else if (axi_dmac_dest_is_mem(chan) && !axi_dmac_src_is_mem(chan))
+		chan->direction = DMA_DEV_TO_MEM;
+	else
+		chan->direction = DMA_DEV_TO_DEV;
+}
+
 /*
  * The configuration stored in the devicetree matches the configuration
  * parameters of the peripheral instance and allows the driver to know which
@@ -760,16 +774,7 @@ static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
 		return ret;
 	chan->dest_width = val / 8;
 
-	chan->address_align_mask = max(chan->dest_width, chan->src_width) - 1;
-
-	if (axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
-		chan->direction = DMA_MEM_TO_MEM;
-	else if (!axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
-		chan->direction = DMA_MEM_TO_DEV;
-	else if (axi_dmac_dest_is_mem(chan) && !axi_dmac_src_is_mem(chan))
-		chan->direction = DMA_DEV_TO_MEM;
-	else
-		chan->direction = DMA_DEV_TO_DEV;
+	axi_dmac_adjust_chan_params(chan);
 
 	return 0;
 }
-- 
2.17.1

[RESEND PATCH v2 6/6] dmaengine: axi-dmac: add support for reading bus attributes from registers

[Alexandru Ardelean]

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: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 66 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 7ee56ae60093..25442a437879 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -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;
 
-	ret = axi_dmac_parse_dt(&pdev->dev, dmac);
+	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;
-- 
2.17.1

Re: [RESEND PATCH v2 0/6] dmaengine: axi-dmac: add support for reading bus attributes from register

[Vinod Koul]

On 25-08-20, 18:19, Alexandru Ardelean wrote:
> The series adds support for reading the DMA bus attributes from the
> INTERFACE_DESCRIPTION (0x10) register.
> 
> The first 5 changes are a bit of rework prior to adding the actual
> change in patch 6, as things need to be shifted around a bit, to enable 
> the clock to be enabled earlier, to be able to read the version
> register.

Applied, thanks

-- 
~Vinod