diff mbox series

[v6,2/9] doc: DT: venus: binding document for Qualcomm video driver

Message ID 1486473024-21705-3-git-send-email-stanimir.varbanov@linaro.org
State Superseded
Headers show
Series None | expand

Commit Message

Stanimir Varbanov Feb. 7, 2017, 1:10 p.m. UTC
Add binding document for Venus video encoder/decoder driver

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>

---
Changes since previous v5:
 * dropped rproc phandle (remoteproc is not used anymore)
 * added subnodes paragraph with descrition of three subnodes:
    - video-decoder and video-encoder - describes decoder (core0) and
    encoder (core1) power-domains and clocks (applicable for msm8996
    Venus core).
    - video-firmware - needed to get reserved memory region where the
    firmware is stored.

 .../devicetree/bindings/media/qcom,venus.txt       | 112 +++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/qcom,venus.txt

-- 
2.7.4

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Comments

Stanimir Varbanov Feb. 22, 2017, 9:25 a.m. UTC | #1
Hi Rob,

On 02/22/2017 02:09 AM, Rob Herring wrote:
> On Tue, Feb 07, 2017 at 03:10:17PM +0200, Stanimir Varbanov wrote:

>> Add binding document for Venus video encoder/decoder driver

>>

>> Cc: Rob Herring <robh+dt@kernel.org>

>> Cc: devicetree@vger.kernel.org

>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>

>> ---

>> Changes since previous v5:

>>  * dropped rproc phandle (remoteproc is not used anymore)

>>  * added subnodes paragraph with descrition of three subnodes:

>>     - video-decoder and video-encoder - describes decoder (core0) and

>>     encoder (core1) power-domains and clocks (applicable for msm8996

>>     Venus core).

>>     - video-firmware - needed to get reserved memory region where the

>>     firmware is stored.

>>

>>  .../devicetree/bindings/media/qcom,venus.txt       | 112 +++++++++++++++++++++

>>  1 file changed, 112 insertions(+)

>>  create mode 100644 Documentation/devicetree/bindings/media/qcom,venus.txt

>>

>> diff --git a/Documentation/devicetree/bindings/media/qcom,venus.txt b/Documentation/devicetree/bindings/media/qcom,venus.txt

>> new file mode 100644

>> index 000000000000..4427af3ca5a5

>> --- /dev/null

>> +++ b/Documentation/devicetree/bindings/media/qcom,venus.txt

>> @@ -0,0 +1,112 @@

> 

> [...]

> 

>> +* Subnodes

>> +The Venus node must contain three subnodes representing video-decoder,

>> +video-encoder and video-firmware.

> 

> [...]

> 

>> +The video-firmware subnode should contain:

>> +

>> +- memory-region:

>> +	Usage: required

>> +	Value type: <phandle>

>> +	Definition: reference to the reserved-memory for the memory region

>> +

>> +* An Example

>> +	video-codec@1d00000 {

>> +		compatible = "qcom,msm8916-venus";

>> +		reg = <0x01d00000 0xff000>;

>> +		interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;

>> +		clocks = <&gcc GCC_VENUS0_VCODEC0_CLK>,

>> +			 <&gcc GCC_VENUS0_AHB_CLK>,

>> +			 <&gcc GCC_VENUS0_AXI_CLK>;

>> +		clock-names = "core", "iface", "bus";

>> +		power-domains = <&gcc VENUS_GDSC>;

>> +		iommus = <&apps_iommu 5>;

>> +

>> +		video-decoder {

>> +			compatible = "venus-decoder";

>> +			clocks = <&mmcc VIDEO_SUBCORE0_CLK>;

>> +			clock-names = "core";

>> +			power-domains = <&mmcc VENUS_CORE0_GDSC>;

>> +		};

>> +

>> +		video-encoder {

>> +			compatible = "venus-encoder";

>> +			clocks = <&mmcc VIDEO_SUBCORE1_CLK>;

>> +			clock-names = "core";

>> +			power-domains = <&mmcc VENUS_CORE1_GDSC>;

>> +		};

>> +

>> +		video-firmware {

>> +			memory-region = <&venus_mem>;

> 

> Why does this need to be a sub node?


Because firmware reserved memory region must have separate struct
device, otherwise allocating video buffers (and map them through iommu)
for video-codec will fail because dma_alloc_coherent trying to allocate
from per-device coherent area.

-- 
regards,
Stan
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Rob Herring (Arm) Feb. 22, 2017, 2:17 p.m. UTC | #2
On Wed, Feb 22, 2017 at 3:25 AM, Stanimir Varbanov
<stanimir.varbanov@linaro.org> wrote:
> Hi Rob,

>

> On 02/22/2017 02:09 AM, Rob Herring wrote:

>> On Tue, Feb 07, 2017 at 03:10:17PM +0200, Stanimir Varbanov wrote:

>>> Add binding document for Venus video encoder/decoder driver

>>>

>>> Cc: Rob Herring <robh+dt@kernel.org>

>>> Cc: devicetree@vger.kernel.org

>>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>

>>> ---

>>> Changes since previous v5:

>>>  * dropped rproc phandle (remoteproc is not used anymore)

>>>  * added subnodes paragraph with descrition of three subnodes:

>>>     - video-decoder and video-encoder - describes decoder (core0) and

>>>     encoder (core1) power-domains and clocks (applicable for msm8996

>>>     Venus core).

>>>     - video-firmware - needed to get reserved memory region where the

>>>     firmware is stored.

>>>

>>>  .../devicetree/bindings/media/qcom,venus.txt       | 112 +++++++++++++++++++++

>>>  1 file changed, 112 insertions(+)

>>>  create mode 100644 Documentation/devicetree/bindings/media/qcom,venus.txt

>>>

>>> diff --git a/Documentation/devicetree/bindings/media/qcom,venus.txt b/Documentation/devicetree/bindings/media/qcom,venus.txt

>>> new file mode 100644

>>> index 000000000000..4427af3ca5a5

>>> --- /dev/null

>>> +++ b/Documentation/devicetree/bindings/media/qcom,venus.txt

>>> @@ -0,0 +1,112 @@

>>

>> [...]

>>

>>> +* Subnodes

>>> +The Venus node must contain three subnodes representing video-decoder,

>>> +video-encoder and video-firmware.

>>

>> [...]

>>

>>> +The video-firmware subnode should contain:

>>> +

>>> +- memory-region:

>>> +    Usage: required

>>> +    Value type: <phandle>

>>> +    Definition: reference to the reserved-memory for the memory region

>>> +

>>> +* An Example

>>> +    video-codec@1d00000 {

>>> +            compatible = "qcom,msm8916-venus";

>>> +            reg = <0x01d00000 0xff000>;

>>> +            interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;

>>> +            clocks = <&gcc GCC_VENUS0_VCODEC0_CLK>,

>>> +                     <&gcc GCC_VENUS0_AHB_CLK>,

>>> +                     <&gcc GCC_VENUS0_AXI_CLK>;

>>> +            clock-names = "core", "iface", "bus";

>>> +            power-domains = <&gcc VENUS_GDSC>;

>>> +            iommus = <&apps_iommu 5>;

>>> +

>>> +            video-decoder {

>>> +                    compatible = "venus-decoder";

>>> +                    clocks = <&mmcc VIDEO_SUBCORE0_CLK>;

>>> +                    clock-names = "core";

>>> +                    power-domains = <&mmcc VENUS_CORE0_GDSC>;

>>> +            };

>>> +

>>> +            video-encoder {

>>> +                    compatible = "venus-encoder";

>>> +                    clocks = <&mmcc VIDEO_SUBCORE1_CLK>;

>>> +                    clock-names = "core";

>>> +                    power-domains = <&mmcc VENUS_CORE1_GDSC>;

>>> +            };

>>> +

>>> +            video-firmware {

>>> +                    memory-region = <&venus_mem>;

>>

>> Why does this need to be a sub node?

>

> Because firmware reserved memory region must have separate struct

> device, otherwise allocating video buffers (and map them through iommu)

> for video-codec will fail because dma_alloc_coherent trying to allocate

> from per-device coherent area.


Why can't the struct device be the video-codec device? Looking at the
code, I don't see why you need the 2nd struct device.

In any case, this is letting the driver design the binding which is
wrong. From a binding perspective, there's no reason to have this
node.

Rob
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Stanimir Varbanov Feb. 23, 2017, 1:08 p.m. UTC | #3
On 02/22/2017 04:17 PM, Rob Herring wrote:
> On Wed, Feb 22, 2017 at 3:25 AM, Stanimir Varbanov

> <stanimir.varbanov@linaro.org> wrote:

>> Hi Rob,

>>

>> On 02/22/2017 02:09 AM, Rob Herring wrote:

>>> On Tue, Feb 07, 2017 at 03:10:17PM +0200, Stanimir Varbanov wrote:

>>>> Add binding document for Venus video encoder/decoder driver

>>>>

>>>> Cc: Rob Herring <robh+dt@kernel.org>

>>>> Cc: devicetree@vger.kernel.org

>>>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>

>>>> ---

>>>> Changes since previous v5:

>>>>  * dropped rproc phandle (remoteproc is not used anymore)

>>>>  * added subnodes paragraph with descrition of three subnodes:

>>>>     - video-decoder and video-encoder - describes decoder (core0) and

>>>>     encoder (core1) power-domains and clocks (applicable for msm8996

>>>>     Venus core).

>>>>     - video-firmware - needed to get reserved memory region where the

>>>>     firmware is stored.

>>>>

>>>>  .../devicetree/bindings/media/qcom,venus.txt       | 112 +++++++++++++++++++++

>>>>  1 file changed, 112 insertions(+)

>>>>  create mode 100644 Documentation/devicetree/bindings/media/qcom,venus.txt

>>>>

>>>> diff --git a/Documentation/devicetree/bindings/media/qcom,venus.txt b/Documentation/devicetree/bindings/media/qcom,venus.txt

>>>> new file mode 100644

>>>> index 000000000000..4427af3ca5a5

>>>> --- /dev/null

>>>> +++ b/Documentation/devicetree/bindings/media/qcom,venus.txt

>>>> @@ -0,0 +1,112 @@

>>>

>>> [...]

>>>

>>>> +* Subnodes

>>>> +The Venus node must contain three subnodes representing video-decoder,

>>>> +video-encoder and video-firmware.

>>>

>>> [...]

>>>

>>>> +The video-firmware subnode should contain:

>>>> +

>>>> +- memory-region:

>>>> +    Usage: required

>>>> +    Value type: <phandle>

>>>> +    Definition: reference to the reserved-memory for the memory region

>>>> +

>>>> +* An Example

>>>> +    video-codec@1d00000 {

>>>> +            compatible = "qcom,msm8916-venus";

>>>> +            reg = <0x01d00000 0xff000>;

>>>> +            interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;

>>>> +            clocks = <&gcc GCC_VENUS0_VCODEC0_CLK>,

>>>> +                     <&gcc GCC_VENUS0_AHB_CLK>,

>>>> +                     <&gcc GCC_VENUS0_AXI_CLK>;

>>>> +            clock-names = "core", "iface", "bus";

>>>> +            power-domains = <&gcc VENUS_GDSC>;

>>>> +            iommus = <&apps_iommu 5>;

>>>> +

>>>> +            video-decoder {

>>>> +                    compatible = "venus-decoder";

>>>> +                    clocks = <&mmcc VIDEO_SUBCORE0_CLK>;

>>>> +                    clock-names = "core";

>>>> +                    power-domains = <&mmcc VENUS_CORE0_GDSC>;

>>>> +            };

>>>> +

>>>> +            video-encoder {

>>>> +                    compatible = "venus-encoder";

>>>> +                    clocks = <&mmcc VIDEO_SUBCORE1_CLK>;

>>>> +                    clock-names = "core";

>>>> +                    power-domains = <&mmcc VENUS_CORE1_GDSC>;

>>>> +            };

>>>> +

>>>> +            video-firmware {

>>>> +                    memory-region = <&venus_mem>;

>>>

>>> Why does this need to be a sub node?

>>

>> Because firmware reserved memory region must have separate struct

>> device, otherwise allocating video buffers (and map them through iommu)

>> for video-codec will fail because dma_alloc_coherent trying to allocate

>> from per-device coherent area.

> 

> Why can't the struct device be the video-codec device? Looking at the

> code, I don't see why you need the 2nd struct device.


The issue when using one device (video-codec device) is coming from
dma_alloc_from_coherent() which is called by dma_alloc_attrs(). The
firmware memory-region is parsed and initialize coherent memory such a
region with flag DMA_MEMORY_EXCLUSIVE which means that following
invocations of dma_alloc_coherent (for example to allocate video buffers
and map them through IOMMU) will no fallback to generic memory allocator
i.e. dma_ops. Because Venus is behind IOMMU the dma_ops are pointing to
iommu_dma_ops for ARM64.

> 

> In any case, this is letting the driver design the binding which is

> wrong. From a binding perspective, there's no reason to have this

> node.


OK, thanks for the comments. I have few changes in the firmware memory
allocation part of the driver which makes possible to remove
video-firmware subnode and move memory-region to video-codec DT node.

Is that fine for you?

-- 
regards,
Stan
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diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/media/qcom,venus.txt b/Documentation/devicetree/bindings/media/qcom,venus.txt
new file mode 100644
index 000000000000..4427af3ca5a5
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/qcom,venus.txt
@@ -0,0 +1,112 @@ 
+* Qualcomm Venus video encode/decode accelerator
+
+- compatible:
+	Usage: required
+	Value type: <stringlist>
+	Definition: Value should contain one of:
+		- "qcom,msm8916-venus"
+		- "qcom,msm8996-venus"
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: Register base address and length of the register map.
+- interrupts:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: Should contain interrupt line number.
+- clocks:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: A List of phandle and clock specifier pairs as listed
+		    in clock-names property.
+- clock-names:
+	Usage: required for msm8916
+	Value type: <stringlist>
+	Definition: Should contain the following entries:
+		- "core"	Core video accelerator clock
+		- "iface"	Video accelerator AHB clock
+		- "bus"		Video accelerator AXI clock
+- clock-names:
+	Usage: required for msm8996
+	Value type: <stringlist>
+	Definition: Should contain the following entries:
+		- "core"	Core video accelerator clock
+		- "iface"	Video accelerator AHB clock
+		- "bus"		Video accelerator AXI clock
+		- "mbus"	Video MAXI clock
+- power-domains:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: A phandle and power domain specifier pairs to the
+		    power domain which is responsible for collapsing
+		    and restoring power to the peripheral.
+- iommus:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: A list of phandle and IOMMU specifier pairs.
+
+* Subnodes
+The Venus node must contain three subnodes representing video-decoder,
+video-encoder and video-firmware.
+
+Every of video-encoder or video-decoder subnode should have:
+
+- compatible:
+	Usage: required
+	Value type: <stringlist>
+	Definition: Value should contain "venus-decoder" or "venus-encoder"
+- clocks:
+	Usage: required for msm8996
+	Value type: <prop-encoded-array>
+	Definition: A List of phandle and clock specifier pairs as listed
+		    in clock-names property.
+- clock-names:
+	Usage: required for msm8996
+	Value type: <stringlist>
+	Definition: Should contain the following entries:
+		- "core"	Subcore video accelerator clock
+
+- power-domains:
+	Usage: required for msm8996
+	Value type: <prop-encoded-array>
+	Definition: A phandle and power domain specifier pairs to the
+		    power domain which is responsible for collapsing
+		    and restoring power to the subcore.
+
+The video-firmware subnode should contain:
+
+- memory-region:
+	Usage: required
+	Value type: <phandle>
+	Definition: reference to the reserved-memory for the memory region
+
+* An Example
+	video-codec@1d00000 {
+		compatible = "qcom,msm8916-venus";
+		reg = <0x01d00000 0xff000>;
+		interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&gcc GCC_VENUS0_VCODEC0_CLK>,
+			 <&gcc GCC_VENUS0_AHB_CLK>,
+			 <&gcc GCC_VENUS0_AXI_CLK>;
+		clock-names = "core", "iface", "bus";
+		power-domains = <&gcc VENUS_GDSC>;
+		iommus = <&apps_iommu 5>;
+
+		video-decoder {
+			compatible = "venus-decoder";
+			clocks = <&mmcc VIDEO_SUBCORE0_CLK>;
+			clock-names = "core";
+			power-domains = <&mmcc VENUS_CORE0_GDSC>;
+		};
+
+		video-encoder {
+			compatible = "venus-encoder";
+			clocks = <&mmcc VIDEO_SUBCORE1_CLK>;
+			clock-names = "core";
+			power-domains = <&mmcc VENUS_CORE1_GDSC>;
+		};
+
+		video-firmware {
+			memory-region = <&venus_mem>;
+		};
+	};