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[v4,1/4] dt-bindings: dmaengine: Add dmamux for CV18XX/SG200X series SoC

Message ID IA1PR20MB49532DE75E794419E58F9268BB2D2@IA1PR20MB4953.namprd20.prod.outlook.com (mailing list archive)
State Superseded
Headers show
Series riscv: sophgo: add dmamux support for Sophgo CV1800/SG2000 SoCs | expand

Commit Message

Inochi Amaoto March 18, 2024, 6:38 a.m. UTC
The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
an additional channel remap register located in the top system control
area. The DMA channel is exclusive to each core.

Add the dmamux binding for CV18XX/SG200X series SoC

Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
 include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
 create mode 100644 include/dt-bindings/dma/cv1800-dma.h

--
2.44.0

Comments

Krzysztof Kozlowski March 18, 2024, 8:08 a.m. UTC | #1
On 18/03/2024 07:38, Inochi Amaoto wrote:
> The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> an additional channel remap register located in the top system control
> area. The DMA channel is exclusive to each core.
> 
> Add the dmamux binding for CV18XX/SG200X series SoC
> 
> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Drop the tag. You introduced here significant changes which were not
even tested last time.

Best regards,
Krzysztof
Krzysztof Kozlowski March 18, 2024, 8:09 a.m. UTC | #2
On 18/03/2024 07:38, Inochi Amaoto wrote:
> The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> an additional channel remap register located in the top system control
> area. The DMA channel is exclusive to each core.
> 
> Add the dmamux binding for CV18XX/SG200X series SoC
> 
> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
>  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
>  2 files changed, 102 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
>  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
> 
> diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> new file mode 100644
> index 000000000000..c813c66737ba
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> @@ -0,0 +1,47 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Sophgo CV1800/SG200 Series DMA mux
> +
> +maintainers:
> +  - Inochi Amaoto <inochiama@outlook.com>
> +
> +allOf:
> +  - $ref: dma-router.yaml#
> +
> +properties:
> +  compatible:
> +    const: sophgo,cv1800-dmamux
> +
> +  reg:
> +    maxItems: 2

You need to describe the items.

> +
> +  '#dma-cells':
> +    const: 3
> +    description:
> +      The first cells is DMA channel. The second one is device id.
> +      The third one is the cpu id.
> +
> +  dma-masters:
> +    maxItems: 1
> +
> +  dma-requests:
> +    const: 8
> +
> +required:
> +  - '#dma-cells'

reg is not required? How do you perform any IO?

> +  - dma-masters
> +


Best regards,
Krzysztof
Inochi Amaoto March 18, 2024, 8:30 a.m. UTC | #3
On Mon, Mar 18, 2024 at 09:09:45AM +0100, Krzysztof Kozlowski wrote:
> On 18/03/2024 07:38, Inochi Amaoto wrote:
> > The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> > an additional channel remap register located in the top system control
> > area. The DMA channel is exclusive to each core.
> > 
> > Add the dmamux binding for CV18XX/SG200X series SoC
> > 
> > Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > ---
> >  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
> >  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
> >  2 files changed, 102 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> >  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
> > 
> > diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> > new file mode 100644
> > index 000000000000..c813c66737ba
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> > @@ -0,0 +1,47 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Sophgo CV1800/SG200 Series DMA mux
> > +
> > +maintainers:
> > +  - Inochi Amaoto <inochiama@outlook.com>
> > +
> > +allOf:
> > +  - $ref: dma-router.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: sophgo,cv1800-dmamux
> > +
> > +  reg:
> > +    maxItems: 2
> 
> You need to describe the items.
> 

I wonder whether reg-name should be introduced, or item description is
just enough?

> > +
> > +  '#dma-cells':
> > +    const: 3
> > +    description:
> > +      The first cells is DMA channel. The second one is device id.
> > +      The third one is the cpu id.
> > +
> > +  dma-masters:
> > +    maxItems: 1
> > +
> > +  dma-requests:
> > +    const: 8
> > +
> > +required:
> > +  - '#dma-cells'
> 
> reg is not required? How do you perform any IO?

This device is part of the syscon. The IO is performed by the offset.
In the v2, Rob suggest me add the "reg" property to describe registers.
He also mentioned that driver may not use this info, so I do not make
this a must.

> 
> > +  - dma-masters
> > +
> 
> 
> Best regards,
> Krzysztof
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Krzysztof Kozlowski March 18, 2024, 8:31 a.m. UTC | #4
On 18/03/2024 09:30, Inochi Amaoto wrote:
>>> @@ -0,0 +1,47 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Sophgo CV1800/SG200 Series DMA mux
>>> +
>>> +maintainers:
>>> +  - Inochi Amaoto <inochiama@outlook.com>
>>> +
>>> +allOf:
>>> +  - $ref: dma-router.yaml#
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: sophgo,cv1800-dmamux
>>> +
>>> +  reg:
>>> +    maxItems: 2
>>
>> You need to describe the items.
>>
> 
> I wonder whether reg-name should be introduced, or item description is
> just enough?

items:
 - description:
 - description:

is enough

> 
>>> +
>>> +  '#dma-cells':
>>> +    const: 3
>>> +    description:
>>> +      The first cells is DMA channel. The second one is device id.
>>> +      The third one is the cpu id.
>>> +
>>> +  dma-masters:
>>> +    maxItems: 1
>>> +
>>> +  dma-requests:
>>> +    const: 8
>>> +
>>> +required:
>>> +  - '#dma-cells'
>>
>> reg is not required? How do you perform any IO?
> 
> This device is part of the syscon. The IO is performed by the offset.
> In the v2, Rob suggest me add the "reg" property to describe registers.
> He also mentioned that driver may not use this info, so I do not make
> this a must.

OK

Best regards,
Krzysztof
Samuel Holland March 19, 2024, 3:22 a.m. UTC | #5
On 2024-03-18 1:38 AM, Inochi Amaoto wrote:
> The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> an additional channel remap register located in the top system control
> area. The DMA channel is exclusive to each core.
> 
> Add the dmamux binding for CV18XX/SG200X series SoC
> 
> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
>  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
>  2 files changed, 102 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
>  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
> 
> diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> new file mode 100644
> index 000000000000..c813c66737ba
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> @@ -0,0 +1,47 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Sophgo CV1800/SG200 Series DMA mux
> +
> +maintainers:
> +  - Inochi Amaoto <inochiama@outlook.com>
> +
> +allOf:
> +  - $ref: dma-router.yaml#
> +
> +properties:
> +  compatible:
> +    const: sophgo,cv1800-dmamux
> +
> +  reg:
> +    maxItems: 2
> +
> +  '#dma-cells':
> +    const: 3
> +    description:
> +      The first cells is DMA channel. The second one is device id.
> +      The third one is the cpu id.

There are 43 devices, but only 8 channels. Since the channel is statically
specified in the devicetree as the first cell here, that means the SoC DT author
must pre-select which 8 of the 43 devices are usable, right? And then the rest
would have to omit their dma properties. Wouldn't it be better to leave out the
channel number here and dynamically allocate channels at runtime?

Regards,
Samuel

> +
> +  dma-masters:
> +    maxItems: 1
> +
> +  dma-requests:
> +    const: 8
> +
> +required:
> +  - '#dma-cells'
> +  - dma-masters
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    dma-router {
> +      compatible = "sophgo,cv1800-dmamux";
> +      #dma-cells = <3>;
> +      dma-masters = <&dmac>;
> +      dma-requests = <8>;
> +    };
> diff --git a/include/dt-bindings/dma/cv1800-dma.h b/include/dt-bindings/dma/cv1800-dma.h
> new file mode 100644
> index 000000000000..3ce9dac25259
> --- /dev/null
> +++ b/include/dt-bindings/dma/cv1800-dma.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> +
> +#ifndef __DT_BINDINGS_DMA_CV1800_H__
> +#define __DT_BINDINGS_DMA_CV1800_H__
> +
> +#define DMA_I2S0_RX		0
> +#define DMA_I2S0_TX		1
> +#define DMA_I2S1_RX		2
> +#define DMA_I2S1_TX		3
> +#define DMA_I2S2_RX		4
> +#define DMA_I2S2_TX		5
> +#define DMA_I2S3_RX		6
> +#define DMA_I2S3_TX		7
> +#define DMA_UART0_RX		8
> +#define DMA_UART0_TX		9
> +#define DMA_UART1_RX		10
> +#define DMA_UART1_TX		11
> +#define DMA_UART2_RX		12
> +#define DMA_UART2_TX		13
> +#define DMA_UART3_RX		14
> +#define DMA_UART3_TX		15
> +#define DMA_SPI0_RX		16
> +#define DMA_SPI0_TX		17
> +#define DMA_SPI1_RX		18
> +#define DMA_SPI1_TX		19
> +#define DMA_SPI2_RX		20
> +#define DMA_SPI2_TX		21
> +#define DMA_SPI3_RX		22
> +#define DMA_SPI3_TX		23
> +#define DMA_I2C0_RX		24
> +#define DMA_I2C0_TX		25
> +#define DMA_I2C1_RX		26
> +#define DMA_I2C1_TX		27
> +#define DMA_I2C2_RX		28
> +#define DMA_I2C2_TX		29
> +#define DMA_I2C3_RX		30
> +#define DMA_I2C3_TX		31
> +#define DMA_I2C4_RX		32
> +#define DMA_I2C4_TX		33
> +#define DMA_TDM0_RX		34
> +#define DMA_TDM0_TX		35
> +#define DMA_TDM1_RX		36
> +#define DMA_AUDSRC		37
> +#define DMA_SPI_NAND		38
> +#define DMA_SPI_NOR		39
> +#define DMA_UART4_RX		40
> +#define DMA_UART4_TX		41
> +#define DMA_SPI_NOR1		42
> +
> +#define DMA_CPU_A53		0
> +#define DMA_CPU_C906_0		1
> +#define DMA_CPU_C906_1		2
> +
> +
> +#endif // __DT_BINDINGS_DMA_CV1800_H__
> --
> 2.44.0
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Inochi Amaoto March 19, 2024, 4:03 a.m. UTC | #6
On Mon, Mar 18, 2024 at 10:22:47PM -0500, Samuel Holland wrote:
> On 2024-03-18 1:38 AM, Inochi Amaoto wrote:
> > The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> > an additional channel remap register located in the top system control
> > area. The DMA channel is exclusive to each core.
> > 
> > Add the dmamux binding for CV18XX/SG200X series SoC
> > 
> > Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > ---
> >  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
> >  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
> >  2 files changed, 102 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> >  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
> > 
> > diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> > new file mode 100644
> > index 000000000000..c813c66737ba
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> > @@ -0,0 +1,47 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Sophgo CV1800/SG200 Series DMA mux
> > +
> > +maintainers:
> > +  - Inochi Amaoto <inochiama@outlook.com>
> > +
> > +allOf:
> > +  - $ref: dma-router.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: sophgo,cv1800-dmamux
> > +
> > +  reg:
> > +    maxItems: 2
> > +
> > +  '#dma-cells':
> > +    const: 3
> > +    description:
> > +      The first cells is DMA channel. The second one is device id.
> > +      The third one is the cpu id.
> 
> There are 43 devices, but only 8 channels. Since the channel is statically
> specified in the devicetree as the first cell here, that means the SoC DT author
> must pre-select which 8 of the 43 devices are usable, right? 

Yes, you are right.

> And then the rest
> would have to omit their dma properties. Wouldn't it be better to leave out the
> channel number here and dynamically allocate channels at runtime?
> 

You mean defining all the dma channel in the device and allocation channel
selectively? This is workable, but it still needs a hint to allocate channel.
Also, according to the information from sophgo, it does not support dynamic 
channel allocation, so all channel can only be initialize once.

There is another problem, since we defined all the dmas property in the device,
How to mask the devices if we do not want to use dma on them? I have see SPI
device will disable DMA when allocation failed, I guess this is this mechanism
is the same for all devices?

Regards,
Inochi

> Regards,
> Samuel
> 
> > +
> > +  dma-masters:
> > +    maxItems: 1
> > +
> > +  dma-requests:
> > +    const: 8
> > +
> > +required:
> > +  - '#dma-cells'
> > +  - dma-masters
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    dma-router {
> > +      compatible = "sophgo,cv1800-dmamux";
> > +      #dma-cells = <3>;
> > +      dma-masters = <&dmac>;
> > +      dma-requests = <8>;
> > +    };
> > diff --git a/include/dt-bindings/dma/cv1800-dma.h b/include/dt-bindings/dma/cv1800-dma.h
> > new file mode 100644
> > index 000000000000..3ce9dac25259
> > --- /dev/null
> > +++ b/include/dt-bindings/dma/cv1800-dma.h
> > @@ -0,0 +1,55 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> > +
> > +#ifndef __DT_BINDINGS_DMA_CV1800_H__
> > +#define __DT_BINDINGS_DMA_CV1800_H__
> > +
> > +#define DMA_I2S0_RX		0
> > +#define DMA_I2S0_TX		1
> > +#define DMA_I2S1_RX		2
> > +#define DMA_I2S1_TX		3
> > +#define DMA_I2S2_RX		4
> > +#define DMA_I2S2_TX		5
> > +#define DMA_I2S3_RX		6
> > +#define DMA_I2S3_TX		7
> > +#define DMA_UART0_RX		8
> > +#define DMA_UART0_TX		9
> > +#define DMA_UART1_RX		10
> > +#define DMA_UART1_TX		11
> > +#define DMA_UART2_RX		12
> > +#define DMA_UART2_TX		13
> > +#define DMA_UART3_RX		14
> > +#define DMA_UART3_TX		15
> > +#define DMA_SPI0_RX		16
> > +#define DMA_SPI0_TX		17
> > +#define DMA_SPI1_RX		18
> > +#define DMA_SPI1_TX		19
> > +#define DMA_SPI2_RX		20
> > +#define DMA_SPI2_TX		21
> > +#define DMA_SPI3_RX		22
> > +#define DMA_SPI3_TX		23
> > +#define DMA_I2C0_RX		24
> > +#define DMA_I2C0_TX		25
> > +#define DMA_I2C1_RX		26
> > +#define DMA_I2C1_TX		27
> > +#define DMA_I2C2_RX		28
> > +#define DMA_I2C2_TX		29
> > +#define DMA_I2C3_RX		30
> > +#define DMA_I2C3_TX		31
> > +#define DMA_I2C4_RX		32
> > +#define DMA_I2C4_TX		33
> > +#define DMA_TDM0_RX		34
> > +#define DMA_TDM0_TX		35
> > +#define DMA_TDM1_RX		36
> > +#define DMA_AUDSRC		37
> > +#define DMA_SPI_NAND		38
> > +#define DMA_SPI_NOR		39
> > +#define DMA_UART4_RX		40
> > +#define DMA_UART4_TX		41
> > +#define DMA_SPI_NOR1		42
> > +
> > +#define DMA_CPU_A53		0
> > +#define DMA_CPU_C906_0		1
> > +#define DMA_CPU_C906_1		2
> > +
> > +
> > +#endif // __DT_BINDINGS_DMA_CV1800_H__
> > --
> > 2.44.0
> > 
> > 
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv
>
Samuel Holland March 19, 2024, 4:27 a.m. UTC | #7
Hi Inochi,

On 2024-03-18 11:03 PM, Inochi Amaoto wrote:
> On Mon, Mar 18, 2024 at 10:22:47PM -0500, Samuel Holland wrote:
>> On 2024-03-18 1:38 AM, Inochi Amaoto wrote:
>>> The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
>>> an additional channel remap register located in the top system control
>>> area. The DMA channel is exclusive to each core.
>>>
>>> Add the dmamux binding for CV18XX/SG200X series SoC
>>>
>>> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
>>> Reviewed-by: Rob Herring <robh@kernel.org>
>>> ---
>>>  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
>>>  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
>>>  2 files changed, 102 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
>>>  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
>>>
>>> diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
>>> new file mode 100644
>>> index 000000000000..c813c66737ba
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
>>> @@ -0,0 +1,47 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Sophgo CV1800/SG200 Series DMA mux
>>> +
>>> +maintainers:
>>> +  - Inochi Amaoto <inochiama@outlook.com>
>>> +
>>> +allOf:
>>> +  - $ref: dma-router.yaml#
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: sophgo,cv1800-dmamux
>>> +
>>> +  reg:
>>> +    maxItems: 2
>>> +
>>> +  '#dma-cells':
>>> +    const: 3
>>> +    description:
>>> +      The first cells is DMA channel. The second one is device id.
>>> +      The third one is the cpu id.
>>
>> There are 43 devices, but only 8 channels. Since the channel is statically
>> specified in the devicetree as the first cell here, that means the SoC DT author
>> must pre-select which 8 of the 43 devices are usable, right? 
> 
> Yes, you are right.
> 
>> And then the rest
>> would have to omit their dma properties. Wouldn't it be better to leave out the
>> channel number here and dynamically allocate channels at runtime?
>>
> 
> You mean defining all the dma channel in the device and allocation channel
> selectively? This is workable, but it still needs a hint to allocate channel.

I mean allocating hardware channels only when a channel is requested by a client
driver. The dmamux driver could maintain a counter and allocate the channels
sequentially -- then the first 8 calls to cv1800_dmamux_route_allocate() would
succeed and later calls from other devices would fail.

> Also, according to the information from sophgo, it does not support dynamic 
> channel allocation, so all channel can only be initialize once.

That's important to know. In that case, the driver should probably leave the
registers alone in cv1800_dmamux_free(), and then scan to see if a device is
already mapped to a channel before allocating a new one. (Or it should have some
other way of remembering the mapping.) That way a single client can repeatedly
allocate/free its DMA channel without consuming all of the hardware channels.

> There is another problem, since we defined all the dmas property in the device,
> How to mask the devices if we do not want to use dma on them? I have see SPI
> device will disable DMA when allocation failed, I guess this is this mechanism
> is the same for all devices?

I2C/SPI/UART controller drivers generally still work after failing to acquire a
DMA channel. For audio-related drivers, DMA is generally a hard dependency.

If each board has 8 or fewer DMA-capable devices enabled in its DT, there is no
problem. If some board enables more than 8 DMA-capable devices, then it should
use "/delete-property/ dmas;" on the devices that would be least impacted by
missing DMA. Otherwise, which devices get functional DMA depends on driver probe
order.

Normally you wouldn't need to do "/delete-property/ dmas;", because many drivers
only request the DMA channel when actively being used (e.g. userspace has the
TTY/spidev/ALSA device file open), but this doesn't help if you can only assign
each channel once.

Regards,
Samuel

>>> +
>>> +  dma-masters:
>>> +    maxItems: 1
>>> +
>>> +  dma-requests:
>>> +    const: 8
>>> +
>>> +required:
>>> +  - '#dma-cells'
>>> +  - dma-masters
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    dma-router {
>>> +      compatible = "sophgo,cv1800-dmamux";
>>> +      #dma-cells = <3>;
>>> +      dma-masters = <&dmac>;
>>> +      dma-requests = <8>;
>>> +    };
>>> diff --git a/include/dt-bindings/dma/cv1800-dma.h b/include/dt-bindings/dma/cv1800-dma.h
>>> new file mode 100644
>>> index 000000000000..3ce9dac25259
>>> --- /dev/null
>>> +++ b/include/dt-bindings/dma/cv1800-dma.h
>>> @@ -0,0 +1,55 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
>>> +
>>> +#ifndef __DT_BINDINGS_DMA_CV1800_H__
>>> +#define __DT_BINDINGS_DMA_CV1800_H__
>>> +
>>> +#define DMA_I2S0_RX		0
>>> +#define DMA_I2S0_TX		1
>>> +#define DMA_I2S1_RX		2
>>> +#define DMA_I2S1_TX		3
>>> +#define DMA_I2S2_RX		4
>>> +#define DMA_I2S2_TX		5
>>> +#define DMA_I2S3_RX		6
>>> +#define DMA_I2S3_TX		7
>>> +#define DMA_UART0_RX		8
>>> +#define DMA_UART0_TX		9
>>> +#define DMA_UART1_RX		10
>>> +#define DMA_UART1_TX		11
>>> +#define DMA_UART2_RX		12
>>> +#define DMA_UART2_TX		13
>>> +#define DMA_UART3_RX		14
>>> +#define DMA_UART3_TX		15
>>> +#define DMA_SPI0_RX		16
>>> +#define DMA_SPI0_TX		17
>>> +#define DMA_SPI1_RX		18
>>> +#define DMA_SPI1_TX		19
>>> +#define DMA_SPI2_RX		20
>>> +#define DMA_SPI2_TX		21
>>> +#define DMA_SPI3_RX		22
>>> +#define DMA_SPI3_TX		23
>>> +#define DMA_I2C0_RX		24
>>> +#define DMA_I2C0_TX		25
>>> +#define DMA_I2C1_RX		26
>>> +#define DMA_I2C1_TX		27
>>> +#define DMA_I2C2_RX		28
>>> +#define DMA_I2C2_TX		29
>>> +#define DMA_I2C3_RX		30
>>> +#define DMA_I2C3_TX		31
>>> +#define DMA_I2C4_RX		32
>>> +#define DMA_I2C4_TX		33
>>> +#define DMA_TDM0_RX		34
>>> +#define DMA_TDM0_TX		35
>>> +#define DMA_TDM1_RX		36
>>> +#define DMA_AUDSRC		37
>>> +#define DMA_SPI_NAND		38
>>> +#define DMA_SPI_NOR		39
>>> +#define DMA_UART4_RX		40
>>> +#define DMA_UART4_TX		41
>>> +#define DMA_SPI_NOR1		42
>>> +
>>> +#define DMA_CPU_A53		0
>>> +#define DMA_CPU_C906_0		1
>>> +#define DMA_CPU_C906_1		2
>>> +
>>> +
>>> +#endif // __DT_BINDINGS_DMA_CV1800_H__
>>> --
>>> 2.44.0
>>>
>>>
>>> _______________________________________________
>>> linux-riscv mailing list
>>> linux-riscv@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>
Inochi Amaoto March 19, 2024, 5:32 a.m. UTC | #8
On Mon, Mar 18, 2024 at 11:27:37PM -0500, Samuel Holland wrote:
> Hi Inochi,
> 
> On 2024-03-18 11:03 PM, Inochi Amaoto wrote:
> > On Mon, Mar 18, 2024 at 10:22:47PM -0500, Samuel Holland wrote:
> >> On 2024-03-18 1:38 AM, Inochi Amaoto wrote:
> >>> The DMA IP of Sophgo CV18XX/SG200X is based on a DW AXI CORE, with
> >>> an additional channel remap register located in the top system control
> >>> area. The DMA channel is exclusive to each core.
> >>>
> >>> Add the dmamux binding for CV18XX/SG200X series SoC
> >>>
> >>> Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
> >>> Reviewed-by: Rob Herring <robh@kernel.org>
> >>> ---
> >>>  .../bindings/dma/sophgo,cv1800-dmamux.yaml    | 47 ++++++++++++++++
> >>>  include/dt-bindings/dma/cv1800-dma.h          | 55 +++++++++++++++++++
> >>>  2 files changed, 102 insertions(+)
> >>>  create mode 100644 Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> >>>  create mode 100644 include/dt-bindings/dma/cv1800-dma.h
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> >>> new file mode 100644
> >>> index 000000000000..c813c66737ba
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
> >>> @@ -0,0 +1,47 @@
> >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>> +%YAML 1.2
> >>> +---
> >>> +$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
> >>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>> +
> >>> +title: Sophgo CV1800/SG200 Series DMA mux
> >>> +
> >>> +maintainers:
> >>> +  - Inochi Amaoto <inochiama@outlook.com>
> >>> +
> >>> +allOf:
> >>> +  - $ref: dma-router.yaml#
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    const: sophgo,cv1800-dmamux
> >>> +
> >>> +  reg:
> >>> +    maxItems: 2
> >>> +
> >>> +  '#dma-cells':
> >>> +    const: 3
> >>> +    description:
> >>> +      The first cells is DMA channel. The second one is device id.
> >>> +      The third one is the cpu id.
> >>
> >> There are 43 devices, but only 8 channels. Since the channel is statically
> >> specified in the devicetree as the first cell here, that means the SoC DT author
> >> must pre-select which 8 of the 43 devices are usable, right? 
> > 
> > Yes, you are right.
> > 
> >> And then the rest
> >> would have to omit their dma properties. Wouldn't it be better to leave out the
> >> channel number here and dynamically allocate channels at runtime?
> >>
> > 
> > You mean defining all the dma channel in the device and allocation channel
> > selectively? This is workable, but it still needs a hint to allocate channel.
> 
> I mean allocating hardware channels only when a channel is requested by a client
> driver. The dmamux driver could maintain a counter and allocate the channels
> sequentially -- then the first 8 calls to cv1800_dmamux_route_allocate() would
> succeed and later calls from other devices would fail.
> 
> > Also, according to the information from sophgo, it does not support dynamic 
> > channel allocation, so all channel can only be initialize once.
> 
> That's important to know. In that case, the driver should probably leave the
> registers alone in cv1800_dmamux_free(), and then scan to see if a device is
> already mapped to a channel before allocating a new one. (Or it should have some
> other way of remembering the mapping.) That way a single client can repeatedly
> allocate/free its DMA channel without consuming all of the hardware channels.
> 

Yes, this is needed.

> > There is another problem, since we defined all the dmas property in the device,
> > How to mask the devices if we do not want to use dma on them? I have see SPI
> > device will disable DMA when allocation failed, I guess this is this mechanism
> > is the same for all devices?
> 
> I2C/SPI/UART controller drivers generally still work after failing to acquire a
> DMA channel. For audio-related drivers, DMA is generally a hard dependency.
> 
> If each board has 8 or fewer DMA-capable devices enabled in its DT, there is no
> problem. If some board enables more than 8 DMA-capable devices, then it should
> use "/delete-property/ dmas;" on the devices that would be least impacted by
> missing DMA. Otherwise, which devices get functional DMA depends on driver probe
> order.
> 
> Normally you wouldn't need to do "/delete-property/ dmas;", because many drivers
> only request the DMA channel when actively being used (e.g. userspace has the
> TTY/spidev/ALSA device file open), but this doesn't help if you can only assign
> each channel once.
> 

That is the problem. It is hard when the register can be only write once.
It may be better to let the end user to determine which device wants dma. 
I will do some more reverse engineering to check whether it is possible
to do a remap, And at least for now, I will implement the basic mechanisms.
Thanks for your explanation.

> Regards,
> Samuel
> 
> >>> +
> >>> +  dma-masters:
> >>> +    maxItems: 1
> >>> +
> >>> +  dma-requests:
> >>> +    const: 8
> >>> +
> >>> +required:
> >>> +  - '#dma-cells'
> >>> +  - dma-masters
> >>> +
> >>> +additionalProperties: false
> >>> +
> >>> +examples:
> >>> +  - |
> >>> +    dma-router {
> >>> +      compatible = "sophgo,cv1800-dmamux";
> >>> +      #dma-cells = <3>;
> >>> +      dma-masters = <&dmac>;
> >>> +      dma-requests = <8>;
> >>> +    };
> >>> diff --git a/include/dt-bindings/dma/cv1800-dma.h b/include/dt-bindings/dma/cv1800-dma.h
> >>> new file mode 100644
> >>> index 000000000000..3ce9dac25259
> >>> --- /dev/null
> >>> +++ b/include/dt-bindings/dma/cv1800-dma.h
> >>> @@ -0,0 +1,55 @@
> >>> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> >>> +
> >>> +#ifndef __DT_BINDINGS_DMA_CV1800_H__
> >>> +#define __DT_BINDINGS_DMA_CV1800_H__
> >>> +
> >>> +#define DMA_I2S0_RX		0
> >>> +#define DMA_I2S0_TX		1
> >>> +#define DMA_I2S1_RX		2
> >>> +#define DMA_I2S1_TX		3
> >>> +#define DMA_I2S2_RX		4
> >>> +#define DMA_I2S2_TX		5
> >>> +#define DMA_I2S3_RX		6
> >>> +#define DMA_I2S3_TX		7
> >>> +#define DMA_UART0_RX		8
> >>> +#define DMA_UART0_TX		9
> >>> +#define DMA_UART1_RX		10
> >>> +#define DMA_UART1_TX		11
> >>> +#define DMA_UART2_RX		12
> >>> +#define DMA_UART2_TX		13
> >>> +#define DMA_UART3_RX		14
> >>> +#define DMA_UART3_TX		15
> >>> +#define DMA_SPI0_RX		16
> >>> +#define DMA_SPI0_TX		17
> >>> +#define DMA_SPI1_RX		18
> >>> +#define DMA_SPI1_TX		19
> >>> +#define DMA_SPI2_RX		20
> >>> +#define DMA_SPI2_TX		21
> >>> +#define DMA_SPI3_RX		22
> >>> +#define DMA_SPI3_TX		23
> >>> +#define DMA_I2C0_RX		24
> >>> +#define DMA_I2C0_TX		25
> >>> +#define DMA_I2C1_RX		26
> >>> +#define DMA_I2C1_TX		27
> >>> +#define DMA_I2C2_RX		28
> >>> +#define DMA_I2C2_TX		29
> >>> +#define DMA_I2C3_RX		30
> >>> +#define DMA_I2C3_TX		31
> >>> +#define DMA_I2C4_RX		32
> >>> +#define DMA_I2C4_TX		33
> >>> +#define DMA_TDM0_RX		34
> >>> +#define DMA_TDM0_TX		35
> >>> +#define DMA_TDM1_RX		36
> >>> +#define DMA_AUDSRC		37
> >>> +#define DMA_SPI_NAND		38
> >>> +#define DMA_SPI_NOR		39
> >>> +#define DMA_UART4_RX		40
> >>> +#define DMA_UART4_TX		41
> >>> +#define DMA_SPI_NOR1		42
> >>> +
> >>> +#define DMA_CPU_A53		0
> >>> +#define DMA_CPU_C906_0		1
> >>> +#define DMA_CPU_C906_1		2
> >>> +
> >>> +
> >>> +#endif // __DT_BINDINGS_DMA_CV1800_H__
> >>> --
> >>> 2.44.0
> >>>
> >>>
> >>> _______________________________________________
> >>> linux-riscv mailing list
> >>> linux-riscv@lists.infradead.org
> >>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> >>
>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
new file mode 100644
index 000000000000..c813c66737ba
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/sophgo,cv1800-dmamux.yaml
@@ -0,0 +1,47 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/sophgo,cv1800-dmamux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo CV1800/SG200 Series DMA mux
+
+maintainers:
+  - Inochi Amaoto <inochiama@outlook.com>
+
+allOf:
+  - $ref: dma-router.yaml#
+
+properties:
+  compatible:
+    const: sophgo,cv1800-dmamux
+
+  reg:
+    maxItems: 2
+
+  '#dma-cells':
+    const: 3
+    description:
+      The first cells is DMA channel. The second one is device id.
+      The third one is the cpu id.
+
+  dma-masters:
+    maxItems: 1
+
+  dma-requests:
+    const: 8
+
+required:
+  - '#dma-cells'
+  - dma-masters
+
+additionalProperties: false
+
+examples:
+  - |
+    dma-router {
+      compatible = "sophgo,cv1800-dmamux";
+      #dma-cells = <3>;
+      dma-masters = <&dmac>;
+      dma-requests = <8>;
+    };
diff --git a/include/dt-bindings/dma/cv1800-dma.h b/include/dt-bindings/dma/cv1800-dma.h
new file mode 100644
index 000000000000..3ce9dac25259
--- /dev/null
+++ b/include/dt-bindings/dma/cv1800-dma.h
@@ -0,0 +1,55 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
+
+#ifndef __DT_BINDINGS_DMA_CV1800_H__
+#define __DT_BINDINGS_DMA_CV1800_H__
+
+#define DMA_I2S0_RX		0
+#define DMA_I2S0_TX		1
+#define DMA_I2S1_RX		2
+#define DMA_I2S1_TX		3
+#define DMA_I2S2_RX		4
+#define DMA_I2S2_TX		5
+#define DMA_I2S3_RX		6
+#define DMA_I2S3_TX		7
+#define DMA_UART0_RX		8
+#define DMA_UART0_TX		9
+#define DMA_UART1_RX		10
+#define DMA_UART1_TX		11
+#define DMA_UART2_RX		12
+#define DMA_UART2_TX		13
+#define DMA_UART3_RX		14
+#define DMA_UART3_TX		15
+#define DMA_SPI0_RX		16
+#define DMA_SPI0_TX		17
+#define DMA_SPI1_RX		18
+#define DMA_SPI1_TX		19
+#define DMA_SPI2_RX		20
+#define DMA_SPI2_TX		21
+#define DMA_SPI3_RX		22
+#define DMA_SPI3_TX		23
+#define DMA_I2C0_RX		24
+#define DMA_I2C0_TX		25
+#define DMA_I2C1_RX		26
+#define DMA_I2C1_TX		27
+#define DMA_I2C2_RX		28
+#define DMA_I2C2_TX		29
+#define DMA_I2C3_RX		30
+#define DMA_I2C3_TX		31
+#define DMA_I2C4_RX		32
+#define DMA_I2C4_TX		33
+#define DMA_TDM0_RX		34
+#define DMA_TDM0_TX		35
+#define DMA_TDM1_RX		36
+#define DMA_AUDSRC		37
+#define DMA_SPI_NAND		38
+#define DMA_SPI_NOR		39
+#define DMA_UART4_RX		40
+#define DMA_UART4_TX		41
+#define DMA_SPI_NOR1		42
+
+#define DMA_CPU_A53		0
+#define DMA_CPU_C906_0		1
+#define DMA_CPU_C906_1		2
+
+
+#endif // __DT_BINDINGS_DMA_CV1800_H__