Re: [PATCH] perf: RISC-V: fix IRQ detection on T-Head C908

[Inochi Amaoto]

On Mon, Mar 11, 2024 at 02:30:18PM +0800, Qingfang Deng wrote:
> T-Head C908 has the same IRQ num and CSR as previous C9xx cores, but
> reports non-zero marchid and mimpid. Remove the ID checks.
> 

Hi, Qingfang,

IIRC, the existed C908 SoC (such as K230) have an early version 
of C908 core. But C908 core itself may support Sscofpmf.
So I do not think removing the ID checks is a good idea. Instead, 
I suggest adding CPUID of your SoC to this check.

Regards,
Inochi

> Fixes: 65e9fb081877 ("drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores")
> Signed-off-by: Qingfang Deng <dqfext@xxxxxxxxx>
> ---
>  arch/riscv/errata/thead/errata.c | 4 ----
>  drivers/perf/riscv_pmu_sbi.c     | 4 +---
>  2 files changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
> index b1c410bbc1ae..49ccad5b21bb 100644
> --- a/arch/riscv/errata/thead/errata.c
> +++ b/arch/riscv/errata/thead/errata.c
> @@ -125,10 +125,6 @@ static bool errata_probe_pmu(unsigned int stage,
>  	if (!IS_ENABLED(CONFIG_ERRATA_THEAD_PMU))
>  		return false;
>  
> -	/* target-c9xx cores report arch_id and impid as 0 */
> -	if (arch_id != 0 || impid != 0)
> -		return false;
> -
>  	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
>  		return false;
>  
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 452aab49db1e..87b83184383a 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -811,9 +811,7 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
>  		riscv_pmu_irq_num = RV_IRQ_PMU;
>  		riscv_pmu_use_irq = true;
>  	} else if (IS_ENABLED(CONFIG_ERRATA_THEAD_PMU) &&
> -		   riscv_cached_mvendorid(0) == THEAD_VENDOR_ID &&
> -		   riscv_cached_marchid(0) == 0 &&
> -		   riscv_cached_mimpid(0) == 0) {
> +		   riscv_cached_mvendorid(0) == THEAD_VENDOR_ID) {
>  		riscv_pmu_irq_num = THEAD_C9XX_RV_IRQ_PMU;
>  		riscv_pmu_use_irq = true;
>  	}
> -- 
> 2.34.1
> 
> 
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