[PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT

[PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT

[Heinrich Schuchardt]

The CLINT in the T-HEAD 9xx processors do not support 64bit mmio access to
the MTIMER device. The current schema does not allow to specify this.

OpenSBI currently uses a property 'clint,has-no-64bit-mmio' to indicate the
restriction. Samuael Holland suggested in
lib: utils/timer: Use standard property to specify 32-bit I/O
https://github.com/smaeul/opensbi/commit/b95e9cf7cf93b0af16fc89204378bc59ff30008e
to use "reg-io-width = <4>;" as the reg-io-width property is generally used
in the devicetree schema for such a condition.

A release candidate of the ACLINT specification is available at
https://github.com/riscv/riscv-aclint/releases

Add reg-io-width as optional property to the SiFive Core Local Interruptor.
Add a new compatible string "allwinner,sun20i-d1-clint" for the CLINT of
the Allwinner D1 SoC.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 .../devicetree/bindings/timer/sifive,clint.yaml     | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
index a35952f48742..d3b4c6844e2f 100644
--- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
@@ -26,6 +26,7 @@ properties:
       - enum:
           - sifive,fu540-c000-clint
           - canaan,k210-clint
+          - allwinner,sun20i-d1-clint
       - const: sifive,clint0
 
     description:
@@ -33,14 +34,22 @@ properties:
       Supported compatible strings are -
       "sifive,fu540-c000-clint" for the SiFive CLINT v0 as integrated
       onto the SiFive FU540 chip, "canaan,k210-clint" for the SiFive
-      CLINT v0 as integrated onto the Canaan Kendryte K210 chip, and
-      "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
+      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
+      "allwinner,sun20i-d1-clint" for the CLINT in the Allwinner D1 SoC,
+      and "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
       integration tweaks.
       Please refer to sifive-blocks-ip-versioning.txt for details
 
   reg:
     maxItems: 1
 
+  reg-io-width:
+    description: |
+      Some CLINT implementations, e.g. on the T-HEAD 9xx, only support
+      32bit access for MTIMER.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 4
+
   interrupts-extended:
     minItems: 1
 
-- 
2.32.0

Re: [PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT

[Anup Patel]

On Fri, Oct 15, 2021 at 5:37 PM Heinrich Schuchardt
<heinrich.schuchardt@canonical.com> wrote:
>
> The CLINT in the T-HEAD 9xx processors do not support 64bit mmio access to
> the MTIMER device. The current schema does not allow to specify this.
>
> OpenSBI currently uses a property 'clint,has-no-64bit-mmio' to indicate the
> restriction. Samuael Holland suggested in
> lib: utils/timer: Use standard property to specify 32-bit I/O
> https://github.com/smaeul/opensbi/commit/b95e9cf7cf93b0af16fc89204378bc59ff30008e
> to use "reg-io-width = <4>;" as the reg-io-width property is generally used
> in the devicetree schema for such a condition.
>
> A release candidate of the ACLINT specification is available at
> https://github.com/riscv/riscv-aclint/releases
>
> Add reg-io-width as optional property to the SiFive Core Local Interruptor.
> Add a new compatible string "allwinner,sun20i-d1-clint" for the CLINT of
> the Allwinner D1 SoC.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  .../devicetree/bindings/timer/sifive,clint.yaml     | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> index a35952f48742..d3b4c6844e2f 100644
> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> @@ -26,6 +26,7 @@ properties:
>        - enum:
>            - sifive,fu540-c000-clint
>            - canaan,k210-clint
> +          - allwinner,sun20i-d1-clint
>        - const: sifive,clint0
>
>      description:
> @@ -33,14 +34,22 @@ properties:
>        Supported compatible strings are -
>        "sifive,fu540-c000-clint" for the SiFive CLINT v0 as integrated
>        onto the SiFive FU540 chip, "canaan,k210-clint" for the SiFive
> -      CLINT v0 as integrated onto the Canaan Kendryte K210 chip, and
> -      "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
> +      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
> +      "allwinner,sun20i-d1-clint" for the CLINT in the Allwinner D1 SoC,
> +      and "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
>        integration tweaks.
>        Please refer to sifive-blocks-ip-versioning.txt for details
>
>    reg:
>      maxItems: 1
>
> +  reg-io-width:
> +    description: |
> +      Some CLINT implementations, e.g. on the T-HEAD 9xx, only support
> +      32bit access for MTIMER.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    const: 4
> +

Please drop the "reg-io-width" DT property.

Based on discussion on ACLINT MTIMER DT bindings, Rob suggested
using implementation specific compatible string for detecting register IO
width. We should follow the same strategy here as well.

Regards,
Anup

>    interrupts-extended:
>      minItems: 1
>
> --
> 2.32.0
>

Re: [PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT

[Heinrich Schuchardt]

On 10/18/21 06:33, Anup Patel wrote:
> On Fri, Oct 15, 2021 at 5:37 PM Heinrich Schuchardt
> <heinrich.schuchardt@canonical.com> wrote:
>>
>> The CLINT in the T-HEAD 9xx processors do not support 64bit mmio access to
>> the MTIMER device. The current schema does not allow to specify this.
>>
>> OpenSBI currently uses a property 'clint,has-no-64bit-mmio' to indicate the
>> restriction. Samuael Holland suggested in
>> lib: utils/timer: Use standard property to specify 32-bit I/O
>> https://github.com/smaeul/opensbi/commit/b95e9cf7cf93b0af16fc89204378bc59ff30008e
>> to use "reg-io-width = <4>;" as the reg-io-width property is generally used
>> in the devicetree schema for such a condition.
>>
>> A release candidate of the ACLINT specification is available at
>> https://github.com/riscv/riscv-aclint/releases
>>
>> Add reg-io-width as optional property to the SiFive Core Local Interruptor.
>> Add a new compatible string "allwinner,sun20i-d1-clint" for the CLINT of
>> the Allwinner D1 SoC.
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> ---
>>   .../devicetree/bindings/timer/sifive,clint.yaml     | 13 +++++++++++--
>>   1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> index a35952f48742..d3b4c6844e2f 100644
>> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> @@ -26,6 +26,7 @@ properties:
>>         - enum:
>>             - sifive,fu540-c000-clint
>>             - canaan,k210-clint
>> +          - allwinner,sun20i-d1-clint
>>         - const: sifive,clint0
>>
>>       description:
>> @@ -33,14 +34,22 @@ properties:
>>         Supported compatible strings are -
>>         "sifive,fu540-c000-clint" for the SiFive CLINT v0 as integrated
>>         onto the SiFive FU540 chip, "canaan,k210-clint" for the SiFive
>> -      CLINT v0 as integrated onto the Canaan Kendryte K210 chip, and
>> -      "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
>> +      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
>> +      "allwinner,sun20i-d1-clint" for the CLINT in the Allwinner D1 SoC,
>> +      and "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
>>         integration tweaks.
>>         Please refer to sifive-blocks-ip-versioning.txt for details
>>
>>     reg:
>>       maxItems: 1
>>
>> +  reg-io-width:
>> +    description: |
>> +      Some CLINT implementations, e.g. on the T-HEAD 9xx, only support
>> +      32bit access for MTIMER.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    const: 4
>> +
> 
> Please drop the "reg-io-width" DT property.
> 
> Based on discussion on ACLINT MTIMER DT bindings, Rob suggested
> using implementation specific compatible string for detecting register IO
> width. We should follow the same strategy here as well.

Should we create a completely separated yaml document for 
"allwinner,sun20i-d1-clint", "thead,clint0"? Or should we integrate all 
in sifive,clint.yaml?

Best regards

Heinrich

> 
> Regards,
> Anup
> 
>>     interrupts-extended:
>>       minItems: 1
>>
>> --
>> 2.32.0
>>