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

[PATCH 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.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
index a35952f48742..266012d887b5 100644
--- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
@@ -41,6 +41,13 @@ properties:
   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


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

[Bin Meng]

On Fri, Oct 15, 2021 at 6:09 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.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> index a35952f48742..266012d887b5 100644
> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> @@ -41,6 +41,13 @@ properties:
>    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

But this is not a "sifive,clint" anyway. Should there be a new
dt-bindings for T-Head clint variant?

> +
>    interrupts-extended:
>      minItems: 1

Regards,
Bin

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

[Heinrich Schuchardt]

On 10/15/21 12:14, Bin Meng wrote:
> On Fri, Oct 15, 2021 at 6:09 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.
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> ---
>>   Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> index a35952f48742..266012d887b5 100644
>> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>> @@ -41,6 +41,13 @@ properties:
>>     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
> 
> But this is not a "sifive,clint" anyway. Should there be a new
> dt-bindings for T-Head clint variant?

I assume by new dt-bindings variant you mean: Add a new compatible 
string in Documentation/devicetree/bindings/timer/sifive,clint.yaml.

The vendor Debian image uses:
compatible = "{allwinner,sun20i-d1-clint", "sifive,clint0"};

We could add this diff in a future version of the patch:

--- 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:
@@ -33,10 +34,10 @@ 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
+      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
        "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
-      integration tweaks.
-      Please refer to sifive-blocks-ip-versioning.txt for details
+      integration tweaks, and "allwinner,sun20i-d1-clint" for the Allwinner
+      D1. Please refer to sifive-blocks-ip-versioning.txt for details

    reg:
      maxItems: 1

Best regards

Heinrich

> 
>> +
>>     interrupts-extended:
>>       minItems: 1
> 
> Regards,
> Bin
> 


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

[Jessica Clarke]

On 15 Oct 2021, at 12:54, Heinrich Schuchardt <heinrich.schuchardt@canonical.com> wrote:
> 
> On 10/15/21 12:14, Bin Meng wrote:
>> On Fri, Oct 15, 2021 at 6:09 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.
>>> 
>>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>>> ---
>>>  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>> 
>>> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>> index a35952f48742..266012d887b5 100644
>>> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>> @@ -41,6 +41,13 @@ properties:
>>>    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
>> But this is not a "sifive,clint" anyway. Should there be a new
>> dt-bindings for T-Head clint variant?
> 
> I assume by new dt-bindings variant you mean: Add a new compatible string in Documentation/devicetree/bindings/timer/sifive,clint.yaml.
> 
> The vendor Debian image uses:
> compatible = "{allwinner,sun20i-d1-clint", "sifive,clint0”};

I assume Bin means to stop calling it a sifive,clint0 and instead have
something like

    "allwinner,sun20i-d1-clint", "thead,clint0"

as is being done for their non-conforming PLIC. It’s worth pointing out
that the same is true here; the SiFive CLINT supports 64-bit accesses
on RV64, so this is not compatible with a SiFive CLINT. Moreover, the
RISC-V spec was clearly written in a way that intended 64-bit accesses
to be supported for RV64, though was not completely explicit about
that, which has now been resolved (see
https://github.com/riscv/riscv-isa-manual/issues/639), so this CLINT
violates the obvious intent of the pre-1.12 privileged specs (see
Andrew’s message in the issue, which agrees with my reading).

Jess


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

[Heinrich Schuchardt]

On 10/15/21 14:15, Jessica Clarke wrote:
> On 15 Oct 2021, at 12:54, Heinrich Schuchardt <heinrich.schuchardt@canonical.com> wrote:
>>
>> On 10/15/21 12:14, Bin Meng wrote:
>>> On Fri, Oct 15, 2021 at 6:09 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.
>>>>
>>>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>>>> ---
>>>>   Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
>>>>   1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>>> index a35952f48742..266012d887b5 100644
>>>> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>>> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
>>>> @@ -41,6 +41,13 @@ properties:
>>>>     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
>>> But this is not a "sifive,clint" anyway. Should there be a new
>>> dt-bindings for T-Head clint variant?
>>
>> I assume by new dt-bindings variant you mean: Add a new compatible string in Documentation/devicetree/bindings/timer/sifive,clint.yaml.
>>
>> The vendor Debian image uses:
>> compatible = "{allwinner,sun20i-d1-clint", "sifive,clint0”};
> 
> I assume Bin means to stop calling it a sifive,clint0 and instead have
> something like
> 
>      "allwinner,sun20i-d1-clint", "thead,clint0"
> 
> as is being done for their non-conforming PLIC. It’s worth pointing out
> that the same is true here; the SiFive CLINT supports 64-bit accesses
> on RV64, so this is not compatible with a SiFive CLINT. Moreover, the
> RISC-V spec was clearly written in a way that intended 64-bit accesses
> to be supported for RV64, though was not completely explicit about
> that, which has now been resolved (see
> https://github.com/riscv/riscv-isa-manual/issues/639), so this CLINT
> violates the obvious intent of the pre-1.12 privileged specs (see
> Andrew’s message in the issue, which agrees with my reading).
> 
> Jess
> 

This comment is referring to the discussion in

https://lore.kernel.org/lkml/693a609c-4278-84ab-8a9b-448936bb13d0@sholland.org/


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

[Bin Meng]

On Fri, Oct 15, 2021 at 8:15 PM Jessica Clarke <jrtc27@jrtc27.com> wrote:
>
> On 15 Oct 2021, at 12:54, Heinrich Schuchardt <heinrich.schuchardt@canonical.com> wrote:
> >
> > On 10/15/21 12:14, Bin Meng wrote:
> >> On Fri, Oct 15, 2021 at 6:09 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.
> >>>
> >>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> >>> ---
> >>>  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
> >>>  1 file changed, 7 insertions(+)
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> >>> index a35952f48742..266012d887b5 100644
> >>> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> >>> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> >>> @@ -41,6 +41,13 @@ properties:
> >>>    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
> >> But this is not a "sifive,clint" anyway. Should there be a new
> >> dt-bindings for T-Head clint variant?
> >
> > I assume by new dt-bindings variant you mean: Add a new compatible string in Documentation/devicetree/bindings/timer/sifive,clint.yaml.
> >
> > The vendor Debian image uses:
> > compatible = "{allwinner,sun20i-d1-clint", "sifive,clint0”};
>
> I assume Bin means to stop calling it a sifive,clint0 and instead have
> something like
>
>     "allwinner,sun20i-d1-clint", "thead,clint0"

Yep, that's what I wanted to see. Sorry for not being clear. The
T-Head CLINT is definitely not compatible with "sifive,clint0".

> as is being done for their non-conforming PLIC. It’s worth pointing out
> that the same is true here; the SiFive CLINT supports 64-bit accesses
> on RV64, so this is not compatible with a SiFive CLINT. Moreover, the
> RISC-V spec was clearly written in a way that intended 64-bit accesses
> to be supported for RV64, though was not completely explicit about
> that, which has now been resolved (see
> https://github.com/riscv/riscv-isa-manual/issues/639), so this CLINT
> violates the obvious intent of the pre-1.12 privileged specs (see
> Andrew’s message in the issue, which agrees with my reading).

Regards,
Bin

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

[Xiang W]

在 2021-10-15星期五的 12:09 +0200，Heinrich Schuchardt写道：
> 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.
> 
> Signed-off-by: Heinrich Schuchardt
> <heinrich.schuchardt@canonical.com>
> ---
>  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7
> +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git
> a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> index a35952f48742..266012d887b5 100644
> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> @@ -41,6 +41,13 @@ properties:
>    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
>  
I think we can move has_64bit_mmio to fdt_match->data.This way we no
longer rely on 'clint, has-no-64bit-mmio' or 'reg-io-width'

Regards,
Xiang W



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

[Guo Ren]

On Fri, Oct 15, 2021 at 6:10 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.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> index a35952f48742..266012d887b5 100644
> --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> @@ -41,6 +41,13 @@ properties:
>    reg:
>      maxItems: 1
>
> +  reg-io-width:
> +    description: |
> +      Some CLINT implementations, e.g. on the T-HEAD 9xx, only support

         ^^^^^^^^^^^ -> allwinner d1, new version of our processors
would support 64bit access
> +      32bit access for MTIMER.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    const: 4
> +
>    interrupts-extended:
>      minItems: 1
>
> --
> 2.32.0
>
>
> --
> opensbi mailing list
> opensbi@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/opensbi



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/

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