Re: [PATCH v2] perf: RISC-V: fix IRQ detection on T-Head C908
From: Conor Dooley
Date: Mon Mar 18 2024 - 07:43:29 EST
On Mon, Mar 18, 2024 at 06:02:40PM +0800, Qingfang Deng wrote:
> From: Qingfang Deng <qingfang.deng@xxxxxxxxxxxxxxx>
>
> T-Head C908 has the same IRQ num and CSR as previous C9xx cores, but
> reports non-zero marchid and mimpid. Add the check for C908 ID.
>
> Fixes: 65e9fb081877 ("drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores")
> Signed-off-by: Qingfang Deng <qingfang.deng@xxxxxxxxxxxxxxx>
> ---
> v2: add C908 ID check
If you read the replies to v1 in full, you would see I objected there to
this approach and made suggestions as to how I would like it done:
https://lore.kernel.org/linux-riscv/IA1PR20MB4953CEBE4CB6AC7238849353BB282@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
I don't want to see an expansion of these ID checks.
Thanks,
Conor.
>
> arch/riscv/errata/thead/errata.c | 5 +++--
> arch/riscv/include/asm/vendorid_list.h | 2 ++
> drivers/perf/riscv_pmu_sbi.c | 6 ++++--
> 3 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
> index b1c410bbc1ae..da3b34866d8f 100644
> --- a/arch/riscv/errata/thead/errata.c
> +++ b/arch/riscv/errata/thead/errata.c
> @@ -125,8 +125,9 @@ 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)
> + /* Early c9xx cores report arch_id and impid as 0 */
> + if (!((arch_id == 0 && impid == 0) ||
> + (arch_id == THEAD_C908_ARCH_ID && impid == THEAD_C908_IMP_ID)))
> return false;
>
> if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
> diff --git a/arch/riscv/include/asm/vendorid_list.h b/arch/riscv/include/asm/vendorid_list.h
> index 2f2bb0c84f9a..57b3de510d38 100644
> --- a/arch/riscv/include/asm/vendorid_list.h
> +++ b/arch/riscv/include/asm/vendorid_list.h
> @@ -8,5 +8,7 @@
> #define ANDES_VENDOR_ID 0x31e
> #define SIFIVE_VENDOR_ID 0x489
> #define THEAD_VENDOR_ID 0x5b7
> +#define THEAD_C908_ARCH_ID 0x8000000009140d00
> +#define THEAD_C908_IMP_ID 0x8a000
>
> #endif
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index bbd6fe021b3a..34d8689982de 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -833,8 +833,10 @@ static int pmu_sbi_setup_irqs(struct riscv_pmu *pmu, struct platform_device *pde
> 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_marchid(0) == 0 &&
> + riscv_cached_mimpid(0) == 0) ||
> + (riscv_cached_marchid(0) == THEAD_C908_ARCH_ID &&
> + riscv_cached_mimpid(0) == THEAD_C908_IMP_ID))) {
> riscv_pmu_irq_num = THEAD_C9XX_RV_IRQ_PMU;
> riscv_pmu_use_irq = true;
> } else if (riscv_isa_extension_available(NULL, XANDESPMU) &&
> --
> 2.34.1
>
>
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