Re: [PATCH v2 3/3] riscv: dts: sophgo: add zfh for sg2042

Chen Wang
2025-05-27T10:22:16Z

On 2025/5/27 17:34, Han Gao wrote:
> On Thu, May 15, 2025 at 9:33 AM Chen Wang <unicorn_wang@outlook.com> wrote:
>>
>> On 2025/5/14 23:15, Han Gao wrote:
>>> sg2042 support Zfh ISA extension [1].
>>>
>>> Link: https://occ-oss-prod.oss-cn-hangzhou.aliyuncs.com/resource//1737721869472/%E7%8E%84%E9%93%81C910%E4%B8%8EC920R1S6%E7%94%A8%E6%88%B7%E6%89%8B%E5%86%8C%28xrvm%29_20250124.pdf [1]
>>>
>>> Signed-off-by: Han Gao <rabenda.cn@gmail.com>
>>> ---
>>> arch/riscv/boot/dts/sophgo/sg2042-cpus.dtsi | 256 ++++++++++----------
>>> 1 file changed, 128 insertions(+), 128 deletions(-)
>>>
>>> diff --git a/arch/riscv/boot/dts/sophgo/sg2042-cpus.dtsi b/arch/riscv/boot/dts/sophgo/sg2042-cpus.dtsi
>>> index f483f62ab0c4..8dd1a3c60bc4 100644
>>> --- a/arch/riscv/boot/dts/sophgo/sg2042-cpus.dtsi
>>> +++ b/arch/riscv/boot/dts/sophgo/sg2042-cpus.dtsi
>>> @@ -256,11 +256,11 @@ core3 {
>>> cpu0: cpu@0 {
>>> compatible = "thead,c920", "riscv";
>>> device_type = "cpu";
>>> - riscv,isa = "rv64imafdc";
>>> + riscv,isa = "rv64imafdc_zfh";
>> Need not touch this. "riscv,isa" is deprecated and replaced by
>> "riscv,isa-base" & "riscv,isa-extensions".
>>
>> And only adding zfh for this looks a bit werid.
>>
>> Actually, I plan to remove "riscv,isa" later, so please don't touch this
>> from now on.
> I think that since the linux kernel is the upstream for devicetree, it
> cannot yet remove riscv, isa needs to maintain compatibility.

OK, maybe it's not good to remove "riscv,isa".

Can this patch not modify "riscv,isa", but only add something for
"riscv,isa-extensions"?

Chen

>> Thanks,
>>
>> Chen
>>
>>> riscv,isa-base = "rv64i";
>>> riscv,isa-extensions = "i", "m", "a", "f", "d", "c",
>>> "ziccrse", "zicntr", "zicsr",
>>> - "zifencei", "zihpm",
>>> + "zifencei", "zihpm", "zfh",
>>> "xtheadvector";
>>> thead,vlenb = <16>;
>>> reg = <0>;

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