[PATCH v7 13/22] RISC-V: perf: Add a mechanism to defined legacy event encoding

[Atish Patra <atish.patra@linux.dev>]

From: Atish Patra <atishp@rivosinc.com>

RISC-V ISA doesn't define any standard event encodings or specify
any event to counter mapping. Thus, event encoding information
and corresponding counter mapping fot those events needs to be
provided in the driver for each vendor.

Add a framework to support that. The individual platform events
will be added later.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 drivers/perf/riscv_pmu_sbi.c | 70 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index d44f47613aa1..1c0961e09b15 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -10,6 +10,7 @@
 
 #define pr_fmt(fmt) "riscv-pmu-sbi: " fmt
 
+#include <linux/limits.h>
 #include <linux/mod_devicetable.h>
 #include <linux/perf/riscv_pmu.h>
 #include <linux/platform_device.h>
@@ -379,6 +380,71 @@ static int pmu_sbi_check_event_info(void)
 	return result;
 }
 
+/*
+ * Vendor specific PMU events.
+ */
+struct riscv_pmu_event {
+	u64 event_id;
+	u32 counter_mask;
+};
+
+#define HW_OP_UNSUPPORTED		U64_MAX
+#define CACHE_OP_UNSUPPORTED		U64_MAX
+
+#define PERF_MAP_ALL_UNSUPPORTED					\
+	[0 ... PERF_COUNT_HW_MAX - 1] = {HW_OP_UNSUPPORTED, 0x0}
+
+#define PERF_CACHE_MAP_ALL_UNSUPPORTED					\
+[0 ... PERF_COUNT_HW_CACHE_MAX - 1] = {					\
+	[0 ... PERF_COUNT_HW_CACHE_OP_MAX - 1] = {			\
+		[0 ... PERF_COUNT_HW_CACHE_RESULT_MAX - 1] = {		\
+			CACHE_OP_UNSUPPORTED, 0x0			\
+		},							\
+	},								\
+}
+
+struct riscv_vendor_pmu_events {
+	unsigned long vendorid;
+	unsigned long archid;
+	unsigned long implid;
+	const struct riscv_pmu_event *hw_event_map;
+	const struct riscv_pmu_event (*cache_event_map)[PERF_COUNT_HW_CACHE_OP_MAX]
+						       [PERF_COUNT_HW_CACHE_RESULT_MAX];
+};
+
+#define RISCV_VENDOR_PMU_EVENTS(_vendorid, _archid, _implid, _hw_event_map, _cache_event_map) \
+	{ .vendorid = _vendorid, .archid = _archid, .implid = _implid, \
+	  .hw_event_map = _hw_event_map, .cache_event_map = _cache_event_map },
+
+static struct riscv_vendor_pmu_events pmu_vendor_events_table[] = {
+};
+
+static const struct riscv_pmu_event *current_pmu_hw_event_map;
+static const struct riscv_pmu_event (*current_pmu_cache_event_map)[PERF_COUNT_HW_CACHE_OP_MAX]
+							   [PERF_COUNT_HW_CACHE_RESULT_MAX];
+
+static void __init rvpmu_vendor_register_events(void)
+{
+	int cpu = raw_smp_processor_id();
+	unsigned long vendor_id = riscv_cached_mvendorid(cpu);
+	unsigned long impl_id = riscv_cached_mimpid(cpu);
+	unsigned long arch_id = riscv_cached_marchid(cpu);
+
+	for (int i = 0; i < ARRAY_SIZE(pmu_vendor_events_table); i++) {
+		if (pmu_vendor_events_table[i].vendorid == vendor_id &&
+		    pmu_vendor_events_table[i].implid == impl_id &&
+		    pmu_vendor_events_table[i].archid == arch_id) {
+			current_pmu_hw_event_map = pmu_vendor_events_table[i].hw_event_map;
+			current_pmu_cache_event_map = pmu_vendor_events_table[i].cache_event_map;
+			break;
+		}
+	}
+
+	if (!current_pmu_hw_event_map || !current_pmu_cache_event_map) {
+		pr_info("No default PMU events found\n");
+	}
+}
+
 static void rvpmu_sbi_check_event(struct sbi_pmu_event_data *edata)
 {
 	struct sbiret ret;
@@ -1660,8 +1726,10 @@ static int __init rvpmu_devinit(void)
 	 */
 	if (riscv_isa_extension_available(NULL, SSCCFG) &&
 	    riscv_isa_extension_available(NULL, SMCDELEG) &&
-	    riscv_isa_extension_available(NULL, SSCSRIND))
+	    riscv_isa_extension_available(NULL, SSCSRIND)) {
 		static_branch_enable(&riscv_pmu_cdeleg_available);
+		rvpmu_vendor_register_events();
+	}
 
 	if (!(riscv_pmu_sbi_available_boot() || riscv_pmu_cdeleg_available_boot()))
 		return 0;

-- 
2.53.0-Meta