[PATCH 1/3] perf/arm_dsu: Support DSU-110

[Robin Murphy]

DSU-110 sneakily made all the event counters 64-bit, perhaps related
to no longer having AArch32 EL1 to worry about. While the DSU version
itself is not easily discoverable, the size of a counter certainly is.

Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
 drivers/perf/arm_dsu_pmu.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
index cb4fb59fe04b..8663721ee018 100644
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -66,13 +66,6 @@
  */
 #define DSU_PMU_IDX_CYCLE_COUNTER	31
 
-/* All event counters are 32bit, with a 64bit Cycle counter */
-#define DSU_PMU_COUNTER_WIDTH(idx)	\
-	(((idx) == DSU_PMU_IDX_CYCLE_COUNTER) ? 64 : 32)
-
-#define DSU_PMU_COUNTER_MASK(idx)	\
-	GENMASK_ULL((DSU_PMU_COUNTER_WIDTH((idx)) - 1), 0)
-
 #define DSU_EXT_ATTR(_name, _func, _config)		\
 	(&((struct dev_ext_attribute[]) {				\
 		{							\
@@ -107,6 +100,7 @@ struct dsu_hw_events {
  * @num_counters	: Number of event counters implemented by the PMU,
  *			  excluding the cycle counter.
  * @irq			: Interrupt line for counter overflow.
+ * @has_32b_pmevcntr	: Are the non-cycle counters only 32-bit?
  * @cpmceid_bitmap	: Bitmap for the availability of architected common
  *			  events (event_code < 0x40).
  */
@@ -120,6 +114,7 @@ struct dsu_pmu {
 	struct hlist_node		cpuhp_node;
 	s8				num_counters;
 	int				irq;
+	bool				has_32b_pmevcntr;
 	DECLARE_BITMAP(cpmceid_bitmap, DSU_PMU_MAX_COMMON_EVENTS);
 };
 
@@ -328,6 +323,11 @@ static inline void dsu_pmu_set_event(struct dsu_pmu *dsu_pmu,
 	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);
 }
 
+static u64 dsu_pmu_counter_mask(struct hw_perf_event *hw)
+{
+	return (hw->flags && hw->idx != DSU_PMU_IDX_CYCLE_COUNTER) ? U32_MAX : U64_MAX;
+}
+
 static void dsu_pmu_event_update(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
@@ -339,7 +339,7 @@ static void dsu_pmu_event_update(struct perf_event *event)
 		new_count = dsu_pmu_read_counter(event);
 	} while (local64_cmpxchg(&hwc->prev_count, prev_count, new_count) !=
 			prev_count);
-	delta = (new_count - prev_count) & DSU_PMU_COUNTER_MASK(hwc->idx);
+	delta = (new_count - prev_count) & dsu_pmu_counter_mask(hwc);
 	local64_add(delta, &event->count);
 }
 
@@ -362,8 +362,7 @@ static inline u32 dsu_pmu_get_reset_overflow(void)
  */
 static void dsu_pmu_set_event_period(struct perf_event *event)
 {
-	int idx = event->hw.idx;
-	u64 val = DSU_PMU_COUNTER_MASK(idx) >> 1;
+	u64 val = dsu_pmu_counter_mask(&event->hw) >> 1;
 
 	local64_set(&event->hw.prev_count, val);
 	dsu_pmu_write_counter(event, val);
@@ -564,6 +563,7 @@ static int dsu_pmu_event_init(struct perf_event *event)
 		return -EINVAL;
 
 	event->hw.config_base = event->attr.config;
+	event->hw.flags = dsu_pmu->has_32b_pmevcntr;
 	return 0;
 }
 
@@ -664,6 +664,10 @@ static void dsu_pmu_probe_pmu(struct dsu_pmu *dsu_pmu)
 	cpmceid[1] = __dsu_pmu_read_pmceid(1);
 	bitmap_from_arr32(dsu_pmu->cpmceid_bitmap, cpmceid,
 			  DSU_PMU_MAX_COMMON_EVENTS);
+	/* Newer DSUs have 64-bit counters */
+	__dsu_pmu_write_counter(0, U64_MAX);
+	if (__dsu_pmu_read_counter(0) != U64_MAX)
+		dsu_pmu->has_32b_pmevcntr = true;
 }
 
 static void dsu_pmu_set_active_cpu(int cpu, struct dsu_pmu *dsu_pmu)
-- 
2.39.2.101.g768bb238c484.dirty