[PATCH V4 0/4] Add generic DMA DT binding support

[PATCH V4 0/4] Add generic DMA DT binding support

[Padmavathi Venna]

Changes since V3:
        - Make dma-cells property optional as suggested by Rob Herring
        - Add dma-requests and dma-channels properties to DMA controller
          as suggested by Arnd for future-proof
        - Add Acked-by for some of the patches

Changes since V2:
        - Add new filter function for DT case as suggested by Arnd
        - Add xlate as static function
        - Use newly added filter function in xlate.
        - Add Acked-by for some of the patches

Changes since V1:
        - Address the review comments by Arnd Bergmann as below
        - Wording of the properties.
        - Pass pdmac as third parameter to of_dma_controller_register
        - Filter the dma channel based on channel number and dma_device

This patch set adds support for generic dma device tree bindings for
Samsung platforms and is dependent on the following patches from
Vinod Koul next branch
1)of: Add generic device tree DMA helpers
2)dmaengine: add helper function to request a slave DMA channel

This patch set is made based on Vinod Koul next branch

Padmavathi Venna (4):
  DMA: PL330: Add new pl330 filter for DT case.
  DMA: PL330: Add xlate function
  DMA: PL330: Register the DMA controller with the generic DMA helpers
  ARM: dts: pl330: Add #dma-cells for generic dma binding support

 .../devicetree/bindings/dma/arm-pl330.txt          |   21 +++++--
 arch/arm/boot/dts/exynos5250.dtsi                  |   12 ++++
 drivers/dma/pl330.c                                |   64 +++++++++++++++----
 3 files changed, 78 insertions(+), 19 deletions(-)

-- 
1.7.4.4

[PATCH V4 1/4] DMA: PL330: Add new pl330 filter for DT case.

[Padmavathi Venna]

This patch adds a new pl330_dt_filter for DT case to filter the
required channel based on the new filter params and modifies the
old filter only for non-DT case as suggested by Arnd Bergmann.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dma/pl330.c |   29 +++++++++++++++--------------
 1 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index f7edb6f..40e9752 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -606,6 +606,11 @@ struct dma_pl330_desc {
 	struct dma_pl330_chan *pchan;
 };
 
+struct dma_pl330_filter_args {
+	struct dma_pl330_dmac *pdmac;
+	unsigned int chan_id;
+};
+
 static inline void _callback(struct pl330_req *r, enum pl330_op_err err)
 {
 	if (r && r->xfer_cb)
@@ -2352,6 +2357,16 @@ static void dma_pl330_rqcb(void *token, enum pl330_op_err err)
 	tasklet_schedule(&pch->task);
 }
 
+static bool pl330_dt_filter(struct dma_chan *chan, void *param)
+{
+	struct dma_pl330_filter_args *fargs = param;
+
+	if (chan->device != &fargs->pdmac->ddma)
+		return false;
+
+	return (chan->chan_id == fargs->chan_id);
+}
+
 bool pl330_filter(struct dma_chan *chan, void *param)
 {
 	u8 *peri_id;
@@ -2359,20 +2374,6 @@ bool pl330_filter(struct dma_chan *chan, void *param)
 	if (chan->device->dev->driver != &pl330_driver.drv)
 		return false;
 
-#ifdef CONFIG_OF
-	if (chan->device->dev->of_node) {
-		const __be32 *prop_value;
-		phandle phandle;
-		struct device_node *node;
-
-		prop_value = ((struct property *)param)->value;
-		phandle = be32_to_cpup(prop_value++);
-		node = of_find_node_by_phandle(phandle);
-		return ((chan->private == node) &&
-				(chan->chan_id == be32_to_cpup(prop_value)));
-	}
-#endif
-
 	peri_id = chan->private;
 	return *peri_id == (unsigned)param;
 }
-- 
1.7.4.4

[PATCH V4 2/4] DMA: PL330: Add xlate function

[Padmavathi Venna]

Add xlate to translate the device-tree binding information into
the appropriate format. The filter function requires the dma
controller device and dma channel number as filter_params.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dma/pl330.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 40e9752..f5d47e6 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -25,6 +25,7 @@
 #include <linux/amba/pl330.h>
 #include <linux/scatterlist.h>
 #include <linux/of.h>
+#include <linux/of_dma.h>
 
 #include "dmaengine.h"
 #define PL330_MAX_CHAN		8
@@ -2379,6 +2380,30 @@ bool pl330_filter(struct dma_chan *chan, void *param)
 }
 EXPORT_SYMBOL(pl330_filter);
 
+static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
+						struct of_dma *ofdma)
+{
+	int count = dma_spec->args_count;
+	struct dma_pl330_dmac *pdmac = ofdma->of_dma_data;
+	struct dma_pl330_filter_args fargs;
+	dma_cap_mask_t cap;
+
+	if (!pdmac)
+		return NULL;
+
+	if (count != 1)
+		return NULL;
+
+	fargs.pdmac = pdmac;
+	fargs.chan_id = dma_spec->args[0];
+
+	dma_cap_zero(cap);
+	dma_cap_set(DMA_SLAVE, cap);
+	dma_cap_set(DMA_CYCLIC, cap);
+
+	return dma_request_channel(cap, pl330_dt_filter, &fargs);
+}
+
 static int pl330_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct dma_pl330_chan *pch = to_pchan(chan);
-- 
1.7.4.4

[PATCH V4 3/4] DMA: PL330: Register the DMA controller with the generic DMA helpers

[Padmavathi Venna]

This patch registers the pl330 dma controller driver with the generic
device tree dma helper functions.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dma/pl330.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index f5d47e6..fc9c800 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2995,6 +2995,14 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
 		pi->pcfg.data_bus_width / 8, pi->pcfg.num_chan,
 		pi->pcfg.num_peri, pi->pcfg.num_events);
 
+	ret = of_dma_controller_register(adev->dev.of_node,
+					 of_dma_pl330_xlate, pdmac);
+	if (ret) {
+		dev_err(&adev->dev,
+		"unable to register DMA to the generic DT DMA helpers\n");
+		goto probe_err2;
+	}
+
 	return 0;
 
 probe_err2:
@@ -3015,6 +3023,8 @@ static int __devexit pl330_remove(struct amba_device *adev)
 	if (!pdmac)
 		return 0;
 
+	of_dma_controller_free(adev->dev.of_node);
+
 	amba_set_drvdata(adev, NULL);
 
 	/* Idle the DMAC */
-- 
1.7.4.4

[PATCH V4 4/4] ARM: dts: pl330: Add #dma-cells for generic dma binding support

[Padmavathi Venna]

This patch adds #dma-cells property to PL330 DMA controller
nodes for supporting generic dma dt bindings on samsung
exynos5250 platform.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 .../devicetree/bindings/dma/arm-pl330.txt          |   21 +++++++++++++++----
 arch/arm/boot/dts/exynos5250.dtsi                  |   12 +++++++++++
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt
index 36e27d5..2675658 100644
--- a/Documentation/devicetree/bindings/dma/arm-pl330.txt
+++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt
@@ -10,7 +10,11 @@ Required properties:
   - interrupts: interrupt number to the cpu.
 
 Optional properties:
-- dma-coherent      : Present if dma operations are coherent
+  - dma-coherent      : Present if dma operations are coherent
+  - #dma-cells: must be <1>. used to represent the number of integer
+    cells in the dmas property of client device.
+  - dma-channels: contains the total number of DMA channels supported by the DMAC
+  - dma-requests: contains the total number of DMA requests supported by the DMAC
 
 Example:
 
@@ -18,16 +22,23 @@ Example:
 		compatible = "arm,pl330", "arm,primecell";
 		reg = <0x12680000 0x1000>;
 		interrupts = <99>;
+		#dma-cells = <1>;
+		#dma-channels = <8>;
+		#dma-requests = <32>;
 	};
 
 Client drivers (device nodes requiring dma transfers from dev-to-mem or
-mem-to-dev) should specify the DMA channel numbers using a two-value pair
+mem-to-dev) should specify the DMA channel numbers and dma channel names
 as shown below.
 
   [property name]  = <[phandle of the dma controller] [dma request id]>;
+  [property name]  = <[dma channel name]>
 
       where 'dma request id' is the dma request number which is connected
-      to the client controller. The 'property name' is recommended to be
-      of the form <name>-dma-channel.
+      to the client controller. The 'property name' 'dmas' and 'dma-names'
+      as required by the generic dma device tree binding helpers. The dma
+      names correspond 1:1 with the dma request ids in the dmas property.
 
-  Example:  tx-dma-channel = <&pdma0 12>;
+  Example:  dmas = <&pdma0 12
+		    &pdma1 11>;
+	    dma-names = "tx", "rx";
diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi
index 2e3b6ef..c774aae 100644
--- a/arch/arm/boot/dts/exynos5250.dtsi
+++ b/arch/arm/boot/dts/exynos5250.dtsi
@@ -280,24 +280,36 @@
 			compatible = "arm,pl330", "arm,primecell";
 			reg = <0x121A0000 0x1000>;
 			interrupts = <0 34 0>;
+			#dma-cells = <1>;
+			#dma-channels = <8>;
+			#dma-requests = <32>;
 		};
 
 		pdma1: pdma@121B0000 {
 			compatible = "arm,pl330", "arm,primecell";
 			reg = <0x121B0000 0x1000>;
 			interrupts = <0 35 0>;
+			#dma-cells = <1>;
+			#dma-channels = <8>;
+			#dma-requests = <32>;
 		};
 
 		mdma0: mdma@10800000 {
 			compatible = "arm,pl330", "arm,primecell";
 			reg = <0x10800000 0x1000>;
 			interrupts = <0 33 0>;
+			#dma-cells = <1>;
+			#dma-channels = <8>;
+			#dma-requests = <1>;
 		};
 
 		mdma1: mdma@11C10000 {
 			compatible = "arm,pl330", "arm,primecell";
 			reg = <0x11C10000 0x1000>;
 			interrupts = <0 124 0>;
+			#dma-cells = <1>;
+			#dma-channels = <8>;
+			#dma-requests = <1>;
 		};
 	};
 
-- 
1.7.4.4

Re: [PATCH V4 0/4] Add generic DMA DT binding support

[Vinod Koul]

On Thu, Feb 14, 2013 at 09:10:04AM +0530, Padmavathi Venna wrote:

Logically this should have been v5 :)

Applied all, thanks

--
~Vinod
> Changes since V3:
>         - Make dma-cells property optional as suggested by Rob Herring
>         - Add dma-requests and dma-channels properties to DMA controller
>           as suggested by Arnd for future-proof
>         - Add Acked-by for some of the patches
> 
> Changes since V2:
>         - Add new filter function for DT case as suggested by Arnd
>         - Add xlate as static function
>         - Use newly added filter function in xlate.
>         - Add Acked-by for some of the patches
> 
> Changes since V1:
>         - Address the review comments by Arnd Bergmann as below
>         - Wording of the properties.
>         - Pass pdmac as third parameter to of_dma_controller_register
>         - Filter the dma channel based on channel number and dma_device
> 
> This patch set adds support for generic dma device tree bindings for
> Samsung platforms and is dependent on the following patches from
> Vinod Koul next branch
> 1)of: Add generic device tree DMA helpers
> 2)dmaengine: add helper function to request a slave DMA channel
> 
> This patch set is made based on Vinod Koul next branch
> 
> Padmavathi Venna (4):
>   DMA: PL330: Add new pl330 filter for DT case.
>   DMA: PL330: Add xlate function
>   DMA: PL330: Register the DMA controller with the generic DMA helpers
>   ARM: dts: pl330: Add #dma-cells for generic dma binding support
> 
>  .../devicetree/bindings/dma/arm-pl330.txt          |   21 +++++--
>  arch/arm/boot/dts/exynos5250.dtsi                  |   12 ++++
>  drivers/dma/pl330.c                                |   64 +++++++++++++++----
>  3 files changed, 78 insertions(+), 19 deletions(-)
> 
> -- 
> 1.7.4.4
> 

Re: [PATCH V4 4/4] ARM: dts: pl330: Add #dma-cells for generic dma binding support

[Dave Martin]

On Thu, Feb 14, 2013 at 09:10:08AM +0530, Padmavathi Venna wrote:
> This patch adds #dma-cells property to PL330 DMA controller
> nodes for supporting generic dma dt bindings on samsung
> exynos5250 platform.

Can you comment on the following thread?

https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-February/028188.html


Describing DMA controllers is part of a wider problem of how to describe
bus masters in DT.

The key problem is that nobody knows what subset of the bus hierarchy is
accessed by a DMA controller (or something else) in its master role.
Currently I think that the PCI-oriented standard bindings in the ePAPR
specification are not adequate to describe arbitrary SoC platforms,
but maybe I'm missing something or being too pessimistic...

The "what does a master see" problem is mostly independent of your
DMA bindings, except that coherency is not specific to DMA controllers,
and ideally we would describe that in a common way for all masters.
(Also, in general most devices don't power up coherent -- configuration
both in the peripheral and in the bus fabric may be needed before
coherency is established).

Cheers
---Dave

> 
> Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  .../devicetree/bindings/dma/arm-pl330.txt          |   21 +++++++++++++++----
>  arch/arm/boot/dts/exynos5250.dtsi                  |   12 +++++++++++
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt
> index 36e27d5..2675658 100644
> --- a/Documentation/devicetree/bindings/dma/arm-pl330.txt
> +++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt
> @@ -10,7 +10,11 @@ Required properties:
>    - interrupts: interrupt number to the cpu.
>  
>  Optional properties:
> -- dma-coherent      : Present if dma operations are coherent
> +  - dma-coherent      : Present if dma operations are coherent
> +  - #dma-cells: must be <1>. used to represent the number of integer
> +    cells in the dmas property of client device.
> +  - dma-channels: contains the total number of DMA channels supported by the DMAC
> +  - dma-requests: contains the total number of DMA requests supported by the DMAC
>  
>  Example:
>  
> @@ -18,16 +22,23 @@ Example:
>  		compatible = "arm,pl330", "arm,primecell";
>  		reg = <0x12680000 0x1000>;
>  		interrupts = <99>;
> +		#dma-cells = <1>;
> +		#dma-channels = <8>;
> +		#dma-requests = <32>;
>  	};
>  
>  Client drivers (device nodes requiring dma transfers from dev-to-mem or
> -mem-to-dev) should specify the DMA channel numbers using a two-value pair
> +mem-to-dev) should specify the DMA channel numbers and dma channel names
>  as shown below.
>  
>    [property name]  = <[phandle of the dma controller] [dma request id]>;
> +  [property name]  = <[dma channel name]>
>  
>        where 'dma request id' is the dma request number which is connected
> -      to the client controller. The 'property name' is recommended to be
> -      of the form <name>-dma-channel.
> +      to the client controller. The 'property name' 'dmas' and 'dma-names'
> +      as required by the generic dma device tree binding helpers. The dma
> +      names correspond 1:1 with the dma request ids in the dmas property.
>  
> -  Example:  tx-dma-channel = <&pdma0 12>;
> +  Example:  dmas = <&pdma0 12
> +		    &pdma1 11>;
> +	    dma-names = "tx", "rx";
> diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi
> index 2e3b6ef..c774aae 100644
> --- a/arch/arm/boot/dts/exynos5250.dtsi
> +++ b/arch/arm/boot/dts/exynos5250.dtsi
> @@ -280,24 +280,36 @@
>  			compatible = "arm,pl330", "arm,primecell";
>  			reg = <0x121A0000 0x1000>;
>  			interrupts = <0 34 0>;
> +			#dma-cells = <1>;
> +			#dma-channels = <8>;
> +			#dma-requests = <32>;
>  		};
>  
>  		pdma1: pdma@121B0000 {
>  			compatible = "arm,pl330", "arm,primecell";
>  			reg = <0x121B0000 0x1000>;
>  			interrupts = <0 35 0>;
> +			#dma-cells = <1>;
> +			#dma-channels = <8>;
> +			#dma-requests = <32>;
>  		};
>  
>  		mdma0: mdma@10800000 {
>  			compatible = "arm,pl330", "arm,primecell";
>  			reg = <0x10800000 0x1000>;
>  			interrupts = <0 33 0>;
> +			#dma-cells = <1>;
> +			#dma-channels = <8>;
> +			#dma-requests = <1>;
>  		};
>  
>  		mdma1: mdma@11C10000 {
>  			compatible = "arm,pl330", "arm,primecell";
>  			reg = <0x11C10000 0x1000>;
>  			interrupts = <0 124 0>;
> +			#dma-cells = <1>;
> +			#dma-channels = <8>;
> +			#dma-requests = <1>;
>  		};
>  	};
>  
> -- 
> 1.7.4.4
> 
> 
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