ARM: perf: Add support for Scorpion PMUs

Scorpion supports a set of local performance monitor event
selection registers (LPM) sitting behind a cp15 based interface
that extend the architected PMU events to include Scorpion CPU
and Venum VFP specific events. To use these events the user is
expected to program the lpm register with the event code shifted
into the group they care about and then point the PMNx event at
that region+group combo by writing a LPMn_GROUPx event. Add
support for this hardware.

Note: the raw event number is a pure software construct that
allows us to map the multi-dimensional number space of regions,
groups, and event codes into a flat event number space suitable
for use by the perf framework.

This is based on code originally written by Sheetal Sahasrabudhe,
Ashwin Chaugule, and Neil Leeder [1].

[1] https://www.codeaurora.org/cgit/quic/la/kernel/msm/tree/arch/arm/kernel/perf_event_msm.c?h=msm-3.4

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Neil Leeder <nleeder@codeaurora.org>
Cc: Ashwin Chaugule <ashwinc@codeaurora.org>
Cc: Sheetal Sahasrabudhe <sheetals@codeaurora.org>
Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Documentation/devicetree/bindings/arm/pmu.txt

@@ -18,6 +18,8 @@ Required properties:
 	"arm,arm11mpcore-pmu"
 	"arm,arm1176-pmu"
 	"arm,arm1136-pmu"
+	"qcom,scorpion-pmu"
+	"qcom,scorpion-mp-pmu"
 	"qcom,krait-pmu"
 - interrupts : 1 combined interrupt or 1 per core. If the interrupt is a per-cpu
                interrupt (PPI) then 1 interrupt should be specified.

arch/arm/kernel/perf_event_cpu.c

@@ -243,6 +243,8 @@ static const struct of_device_id cpu_pmu_of_device_ids[] = {
 	{.compatible = "arm,arm1176-pmu",	.data = armv6_1176_pmu_init},
 	{.compatible = "arm,arm1136-pmu",	.data = armv6_1136_pmu_init},
 	{.compatible = "qcom,krait-pmu",	.data = krait_pmu_init},
+	{.compatible = "qcom,scorpion-pmu",	.data = scorpion_pmu_init},
+	{.compatible = "qcom,scorpion-mp-pmu",	.data = scorpion_mp_pmu_init},
 	{},
 };
 

arch/arm/kernel/perf_event_v7.c

@@ -140,6 +140,23 @@ enum krait_perf_types {
 	KRAIT_PERFCTR_L1_DTLB_ACCESS			= 0x12210,
 };
 
+/* ARMv7 Scorpion specific event types */
+enum scorpion_perf_types {
+	SCORPION_LPM0_GROUP0				= 0x4c,
+	SCORPION_LPM1_GROUP0				= 0x50,
+	SCORPION_LPM2_GROUP0				= 0x54,
+	SCORPION_L2LPM_GROUP0				= 0x58,
+	SCORPION_VLPM_GROUP0				= 0x5c,
+
+	SCORPION_ICACHE_ACCESS				= 0x10053,
+	SCORPION_ICACHE_MISS				= 0x10052,
+
+	SCORPION_DTLB_ACCESS				= 0x12013,
+	SCORPION_DTLB_MISS				= 0x12012,
+
+	SCORPION_ITLB_MISS				= 0x12021,
+};
+
 /*
  * Cortex-A8 HW events mapping
  *
@@ -481,6 +498,49 @@ static const unsigned krait_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
 	[C(BPU)][C(OP_WRITE)][C(RESULT_MISS)]	= ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
 };
 
+/*
+ * Scorpion HW events mapping
+ */
+static const unsigned scorpion_perf_map[PERF_COUNT_HW_MAX] = {
+	PERF_MAP_ALL_UNSUPPORTED,
+	[PERF_COUNT_HW_CPU_CYCLES]	    = ARMV7_PERFCTR_CPU_CYCLES,
+	[PERF_COUNT_HW_INSTRUCTIONS]	    = ARMV7_PERFCTR_INSTR_EXECUTED,
+	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = ARMV7_PERFCTR_PC_WRITE,
+	[PERF_COUNT_HW_BRANCH_MISSES]	    = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
+	[PERF_COUNT_HW_BUS_CYCLES]	    = ARMV7_PERFCTR_CLOCK_CYCLES,
+};
+
+static const unsigned scorpion_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
+					    [PERF_COUNT_HW_CACHE_OP_MAX]
+					    [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+	PERF_CACHE_MAP_ALL_UNSUPPORTED,
+	/*
+	 * The performance counters don't differentiate between read and write
+	 * accesses/misses so this isn't strictly correct, but it's the best we
+	 * can do. Writes and reads get combined.
+	 */
+	[C(L1D)][C(OP_READ)][C(RESULT_ACCESS)] = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
+	[C(L1D)][C(OP_READ)][C(RESULT_MISS)] = ARMV7_PERFCTR_L1_DCACHE_REFILL,
+	[C(L1D)][C(OP_WRITE)][C(RESULT_ACCESS)] = ARMV7_PERFCTR_L1_DCACHE_ACCESS,
+	[C(L1D)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV7_PERFCTR_L1_DCACHE_REFILL,
+	[C(L1I)][C(OP_READ)][C(RESULT_ACCESS)] = SCORPION_ICACHE_ACCESS,
+	[C(L1I)][C(OP_READ)][C(RESULT_MISS)] = SCORPION_ICACHE_MISS,
+	/*
+	 * Only ITLB misses and DTLB refills are supported.  If users want the
+	 * DTLB refills misses a raw counter must be used.
+	 */
+	[C(DTLB)][C(OP_READ)][C(RESULT_ACCESS)] = SCORPION_DTLB_ACCESS,
+	[C(DTLB)][C(OP_READ)][C(RESULT_MISS)] = SCORPION_DTLB_MISS,
+	[C(DTLB)][C(OP_WRITE)][C(RESULT_ACCESS)] = SCORPION_DTLB_ACCESS,
+	[C(DTLB)][C(OP_WRITE)][C(RESULT_MISS)] = SCORPION_DTLB_MISS,
+	[C(ITLB)][C(OP_READ)][C(RESULT_MISS)] = SCORPION_ITLB_MISS,
+	[C(ITLB)][C(OP_WRITE)][C(RESULT_MISS)] = SCORPION_ITLB_MISS,
+	[C(BPU)][C(OP_READ)][C(RESULT_ACCESS)] = ARMV7_PERFCTR_PC_BRANCH_PRED,
+	[C(BPU)][C(OP_READ)][C(RESULT_MISS)] = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
+	[C(BPU)][C(OP_WRITE)][C(RESULT_ACCESS)] = ARMV7_PERFCTR_PC_BRANCH_PRED,
+	[C(BPU)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
+};
+
 /*
  * Perf Events' indices
  */
@@ -976,6 +1036,12 @@ static int krait_map_event_no_branch(struct perf_event *event)
 				&krait_perf_cache_map, 0xFFFFF);
 }
 
+static int scorpion_map_event(struct perf_event *event)
+{
+	return armpmu_map_event(event, &scorpion_perf_map,
+				&scorpion_perf_cache_map, 0xFFFFF);
+}
+
 static void armv7pmu_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->handle_irq	= armv7pmu_handle_irq;
@@ -1451,6 +1517,344 @@ static int krait_pmu_init(struct arm_pmu *cpu_pmu)
 	cpu_pmu->clear_event_idx = krait_pmu_clear_event_idx;
 	return 0;
 }
+
+/*
+ * Scorpion Local Performance Monitor Register (LPMn)
+ *
+ *            31   30     24     16     8      0
+ *            +--------------------------------+
+ *  LPM0      | EN |  CC  |  CC  |  CC  |  CC  |   N = 1, R = 0
+ *            +--------------------------------+
+ *  LPM1      | EN |  CC  |  CC  |  CC  |  CC  |   N = 1, R = 1
+ *            +--------------------------------+
+ *  LPM2      | EN |  CC  |  CC  |  CC  |  CC  |   N = 1, R = 2
+ *            +--------------------------------+
+ *  L2LPM     | EN |  CC  |  CC  |  CC  |  CC  |   N = 1, R = 3
+ *            +--------------------------------+
+ *  VLPM      | EN |  CC  |  CC  |  CC  |  CC  |   N = 2, R = ?
+ *            +--------------------------------+
+ *              EN | G=3  | G=2  | G=1  | G=0
+ *
+ *
+ *  Event Encoding:
+ *
+ *      hwc->config_base = 0xNRCCG
+ *
+ *      N  = prefix, 1 for Scorpion CPU (LPMn/L2LPM), 2 for Venum VFP (VLPM)
+ *      R  = region register
+ *      CC = class of events the group G is choosing from
+ *      G  = group or particular event
+ *
+ *  Example: 0x12021 is a Scorpion CPU event in LPM2's group 1 with code 2
+ *
+ *  A region (R) corresponds to a piece of the CPU (execution unit, instruction
+ *  unit, etc.) while the event code (CC) corresponds to a particular class of
+ *  events (interrupts for example). An event code is broken down into
+ *  groups (G) that can be mapped into the PMU (irq, fiqs, and irq+fiqs for
+ *  example).
+ */
+
+static u32 scorpion_read_pmresrn(int n)
+{
+	u32 val;
+
+	switch (n) {
+	case 0:
+		asm volatile("mrc p15, 0, %0, c15, c0, 0" : "=r" (val));
+		break;
+	case 1:
+		asm volatile("mrc p15, 1, %0, c15, c0, 0" : "=r" (val));
+		break;
+	case 2:
+		asm volatile("mrc p15, 2, %0, c15, c0, 0" : "=r" (val));
+		break;
+	case 3:
+		asm volatile("mrc p15, 3, %0, c15, c2, 0" : "=r" (val));
+		break;
+	default:
+		BUG(); /* Should be validated in scorpion_pmu_get_event_idx() */
+	}
+
+	return val;
+}
+
+static void scorpion_write_pmresrn(int n, u32 val)
+{
+	switch (n) {
+	case 0:
+		asm volatile("mcr p15, 0, %0, c15, c0, 0" : : "r" (val));
+		break;
+	case 1:
+		asm volatile("mcr p15, 1, %0, c15, c0, 0" : : "r" (val));
+		break;
+	case 2:
+		asm volatile("mcr p15, 2, %0, c15, c0, 0" : : "r" (val));
+		break;
+	case 3:
+		asm volatile("mcr p15, 3, %0, c15, c2, 0" : : "r" (val));
+		break;
+	default:
+		BUG(); /* Should be validated in scorpion_pmu_get_event_idx() */
+	}
+}
+
+static u32 scorpion_get_pmresrn_event(unsigned int region)
+{
+	static const u32 pmresrn_table[] = { SCORPION_LPM0_GROUP0,
+					     SCORPION_LPM1_GROUP0,
+					     SCORPION_LPM2_GROUP0,
+					     SCORPION_L2LPM_GROUP0 };
+	return pmresrn_table[region];
+}
+
+static void scorpion_evt_setup(int idx, u32 config_base)
+{
+	u32 val;
+	u32 mask;
+	u32 vval, fval;
+	unsigned int region = EVENT_REGION(config_base);
+	unsigned int group = EVENT_GROUP(config_base);
+	unsigned int code = EVENT_CODE(config_base);
+	unsigned int group_shift;
+	bool venum_event = EVENT_VENUM(config_base);
+
+	group_shift = group * 8;
+	mask = 0xff << group_shift;
+
+	/* Configure evtsel for the region and group */
+	if (venum_event)
+		val = SCORPION_VLPM_GROUP0;
+	else
+		val = scorpion_get_pmresrn_event(region);
+	val += group;
+	/* Mix in mode-exclusion bits */
+	val |= config_base & (ARMV7_EXCLUDE_USER | ARMV7_EXCLUDE_PL1);
+	armv7_pmnc_write_evtsel(idx, val);
+
+	asm volatile("mcr p15, 0, %0, c9, c15, 0" : : "r" (0));
+
+	if (venum_event) {
+		venum_pre_pmresr(&vval, &fval);
+		val = venum_read_pmresr();
+		val &= ~mask;
+		val |= code << group_shift;
+		val |= PMRESRn_EN;
+		venum_write_pmresr(val);
+		venum_post_pmresr(vval, fval);
+	} else {
+		val = scorpion_read_pmresrn(region);
+		val &= ~mask;
+		val |= code << group_shift;
+		val |= PMRESRn_EN;
+		scorpion_write_pmresrn(region, val);
+	}
+}
+
+static void scorpion_clearpmu(u32 config_base)
+{
+	u32 val;
+	u32 vval, fval;
+	unsigned int region = EVENT_REGION(config_base);
+	unsigned int group = EVENT_GROUP(config_base);
+	bool venum_event = EVENT_VENUM(config_base);
+
+	if (venum_event) {
+		venum_pre_pmresr(&vval, &fval);
+		val = venum_read_pmresr();
+		val = clear_pmresrn_group(val, group);
+		venum_write_pmresr(val);
+		venum_post_pmresr(vval, fval);
+	} else {
+		val = scorpion_read_pmresrn(region);
+		val = clear_pmresrn_group(val, group);
+		scorpion_write_pmresrn(region, val);
+	}
+}
+
+static void scorpion_pmu_disable_event(struct perf_event *event)
+{
+	unsigned long flags;
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu);
+	struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events);
+
+	/* Disable counter and interrupt */
+	raw_spin_lock_irqsave(&events->pmu_lock, flags);
+
+	/* Disable counter */
+	armv7_pmnc_disable_counter(idx);
+
+	/*
+	 * Clear pmresr code (if destined for PMNx counters)
+	 */
+	if (hwc->config_base & KRAIT_EVENT_MASK)
+		scorpion_clearpmu(hwc->config_base);
+
+	/* Disable interrupt for this counter */
+	armv7_pmnc_disable_intens(idx);
+
+	raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
+}
+
+static void scorpion_pmu_enable_event(struct perf_event *event)
+{
+	unsigned long flags;
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu);
+	struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events);
+
+	/*
+	 * Enable counter and interrupt, and set the counter to count
+	 * the event that we're interested in.
+	 */
+	raw_spin_lock_irqsave(&events->pmu_lock, flags);
+
+	/* Disable counter */
+	armv7_pmnc_disable_counter(idx);
+
+	/*
+	 * Set event (if destined for PMNx counters)
+	 * We don't set the event for the cycle counter because we
+	 * don't have the ability to perform event filtering.
+	 */
+	if (hwc->config_base & KRAIT_EVENT_MASK)
+		scorpion_evt_setup(idx, hwc->config_base);
+	else if (idx != ARMV7_IDX_CYCLE_COUNTER)
+		armv7_pmnc_write_evtsel(idx, hwc->config_base);
+
+	/* Enable interrupt for this counter */
+	armv7_pmnc_enable_intens(idx);
+
+	/* Enable counter */
+	armv7_pmnc_enable_counter(idx);
+
+	raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
+}
+
+static void scorpion_pmu_reset(void *info)
+{
+	u32 vval, fval;
+	struct arm_pmu *cpu_pmu = info;
+	u32 idx, nb_cnt = cpu_pmu->num_events;
+
+	armv7pmu_reset(info);
+
+	/* Clear all pmresrs */
+	scorpion_write_pmresrn(0, 0);
+	scorpion_write_pmresrn(1, 0);
+	scorpion_write_pmresrn(2, 0);
+	scorpion_write_pmresrn(3, 0);
+
+	venum_pre_pmresr(&vval, &fval);
+	venum_write_pmresr(0);
+	venum_post_pmresr(vval, fval);
+
+	/* Reset PMxEVNCTCR to sane default */
+	for (idx = ARMV7_IDX_CYCLE_COUNTER; idx < nb_cnt; ++idx) {
+		armv7_pmnc_select_counter(idx);
+		asm volatile("mcr p15, 0, %0, c9, c15, 0" : : "r" (0));
+	}
+}
+
+static int scorpion_event_to_bit(struct perf_event *event, unsigned int region,
+			      unsigned int group)
+{
+	int bit;
+	struct hw_perf_event *hwc = &event->hw;
+	struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu);
+
+	if (hwc->config_base & VENUM_EVENT)
+		bit = SCORPION_VLPM_GROUP0;
+	else
+		bit = scorpion_get_pmresrn_event(region);
+	bit -= scorpion_get_pmresrn_event(0);
+	bit += group;
+	/*
+	 * Lower bits are reserved for use by the counters (see
+	 * armv7pmu_get_event_idx() for more info)
+	 */
+	bit += ARMV7_IDX_COUNTER_LAST(cpu_pmu) + 1;
+
+	return bit;
+}
+
+/*
+ * We check for column exclusion constraints here.
+ * Two events cant use the same group within a pmresr register.
+ */
+static int scorpion_pmu_get_event_idx(struct pmu_hw_events *cpuc,
+				   struct perf_event *event)
+{
+	int idx;
+	int bit = -1;
+	struct hw_perf_event *hwc = &event->hw;
+	unsigned int region = EVENT_REGION(hwc->config_base);
+	unsigned int group = EVENT_GROUP(hwc->config_base);
+	bool venum_event = EVENT_VENUM(hwc->config_base);
+	bool scorpion_event = EVENT_CPU(hwc->config_base);
+
+	if (venum_event || scorpion_event) {
+		/* Ignore invalid events */
+		if (group > 3 || region > 3)
+			return -EINVAL;
+
+		bit = scorpion_event_to_bit(event, region, group);
+		if (test_and_set_bit(bit, cpuc->used_mask))
+			return -EAGAIN;
+	}
+
+	idx = armv7pmu_get_event_idx(cpuc, event);
+	if (idx < 0 && bit >= 0)
+		clear_bit(bit, cpuc->used_mask);
+
+	return idx;
+}
+
+static void scorpion_pmu_clear_event_idx(struct pmu_hw_events *cpuc,
+				      struct perf_event *event)
+{
+	int bit;
+	struct hw_perf_event *hwc = &event->hw;
+	unsigned int region = EVENT_REGION(hwc->config_base);
+	unsigned int group = EVENT_GROUP(hwc->config_base);
+	bool venum_event = EVENT_VENUM(hwc->config_base);
+	bool scorpion_event = EVENT_CPU(hwc->config_base);
+
+	if (venum_event || scorpion_event) {
+		bit = scorpion_event_to_bit(event, region, group);
+		clear_bit(bit, cpuc->used_mask);
+	}
+}
+
+static int scorpion_pmu_init(struct arm_pmu *cpu_pmu)
+{
+	armv7pmu_init(cpu_pmu);
+	cpu_pmu->name		= "armv7_scorpion";
+	cpu_pmu->map_event	= scorpion_map_event;
+	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
+	cpu_pmu->reset		= scorpion_pmu_reset;
+	cpu_pmu->enable		= scorpion_pmu_enable_event;
+	cpu_pmu->disable	= scorpion_pmu_disable_event;
+	cpu_pmu->get_event_idx	= scorpion_pmu_get_event_idx;
+	cpu_pmu->clear_event_idx = scorpion_pmu_clear_event_idx;
+	return 0;
+}
+
+static int scorpion_mp_pmu_init(struct arm_pmu *cpu_pmu)
+{
+	armv7pmu_init(cpu_pmu);
+	cpu_pmu->name		= "armv7_scorpion_mp";
+	cpu_pmu->map_event	= scorpion_map_event;
+	cpu_pmu->num_events	= armv7_read_num_pmnc_events();
+	cpu_pmu->reset		= scorpion_pmu_reset;
+	cpu_pmu->enable		= scorpion_pmu_enable_event;
+	cpu_pmu->disable	= scorpion_pmu_disable_event;
+	cpu_pmu->get_event_idx	= scorpion_pmu_get_event_idx;
+	cpu_pmu->clear_event_idx = scorpion_pmu_clear_event_idx;
+	return 0;
+}
 #else
 static inline int armv7_a8_pmu_init(struct arm_pmu *cpu_pmu)
 {
@@ -1491,4 +1895,14 @@ static inline int krait_pmu_init(struct arm_pmu *cpu_pmu)
 {
 	return -ENODEV;
 }
+
+static inline int scorpion_pmu_init(struct arm_pmu *cpu_pmu)
+{
+	return -ENODEV;
+}
+
+static inline int scorpion_mp_pmu_init(struct arm_pmu *cpu_pmu)
+{
+	return -ENODEV;
+}
 #endif	/* CONFIG_CPU_V7 */