[PATCH v2] perf: RISC-V: fix IRQ detection on T-Head C908

[Qingfang Deng]

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

 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