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From: Ilkka Koskinen <ilkka@os.amperecomputing.com>
To: Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Jing Zhang <renyu.zj@linux.alibaba.com>,
	Ilkka Koskinen <ilkka@os.amperecomputing.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/2] perf/arm-cmn: Decouple wp_config registers from filter group number
Date: Thu,  7 Mar 2024 15:09:28 -0800
Message-ID: <20240307230929.6233-2-ilkka@os.amperecomputing.com>
In-Reply-To: <20240307230929.6233-1-ilkka@os.amperecomputing.com>
References: <20240307230929.6233-1-ilkka@os.amperecomputing.com>
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Previously, wp_config0/2 registers were used for primary match group and
wp_config1/3 registers for secondary match group. In order to support
tertiary match group, this patch decouples the registers and the groups.

Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
---
 drivers/perf/arm-cmn.c | 125 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 105 insertions(+), 20 deletions(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 7e3aa7e2345f..29d46e0cf1cd 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -589,6 +589,13 @@ struct arm_cmn_hw_event {
 	s8 dtc_idx[CMN_MAX_DTCS];
 	u8 num_dns;
 	u8 dtm_offset;
+
+	/*
+	 * WP config registers are divided to UP and DOWN events. We need to
+	 * keep to track only one of them.
+	 */
+	DECLARE_BITMAP(wp_cfg, 2 * CMN_MAX_XPS);
+
 	bool wide_sel;
 	enum cmn_filter_select filter_sel;
 };
@@ -1335,9 +1342,51 @@ static const struct attribute_group *arm_cmn_attr_groups[] = {
 	NULL
 };
 
-static int arm_cmn_wp_idx(struct perf_event *event)
+static inline unsigned int arm_cmn_get_xp_idx(struct arm_cmn *cmn,
+					      struct arm_cmn_node *xp)
 {
-	return CMN_EVENT_EVENTID(event) + CMN_EVENT_WP_GRP(event);
+	return  ((unsigned long) xp - (unsigned long) cmn->xps) / sizeof(struct arm_cmn_node);
+}
+
+static int arm_cmn_find_free_wp_idx(struct arm_cmn *cmn, struct arm_cmn_dtm *dtm,
+				   struct perf_event *event)
+{
+	int wp_idx = CMN_EVENT_EVENTID(event);
+
+	if (dtm->wp_event[wp_idx] >= 0)
+		if (dtm->wp_event[++wp_idx] >= 0)
+			return -ENOSPC;
+
+	return wp_idx;
+}
+
+static int arm_cmn_get_assigned_wp_idx(struct arm_cmn *cmn,
+				       struct arm_cmn_node *xp,
+				       struct perf_event *event,
+				       struct arm_cmn_hw_event *hw)
+{
+	int xp_idx = arm_cmn_get_xp_idx(cmn, xp);
+
+	if (test_bit(2 * xp_idx, hw->wp_cfg))
+		return CMN_EVENT_EVENTID(event);
+	else if (test_bit(2 * xp_idx + 1, hw->wp_cfg))
+		return CMN_EVENT_EVENTID(event) + 1;
+
+	dev_err(cmn->dev, "Could't find the assigned wp_cfg\n");
+	return -EINVAL;
+}
+
+static void arm_cmn_claim_wp_idx(struct arm_cmn *cmn,
+				    struct arm_cmn_dtm *dtm,
+				    struct perf_event *event,
+				    struct arm_cmn_node *xp,
+				    int wp_idx, unsigned int dtc)
+{
+	struct arm_cmn_hw_event *hw = to_cmn_hw(event);
+	int xp_idx = arm_cmn_get_xp_idx(cmn, xp);
+
+	dtm->wp_event[wp_idx] = hw->dtc_idx[dtc];
+	set_bit(2 * xp_idx + (wp_idx & 1), hw->wp_cfg);
 }
 
 static u32 arm_cmn_wp_config(struct perf_event *event)
@@ -1519,12 +1568,16 @@ static void arm_cmn_event_start(struct perf_event *event, int flags)
 		writeq_relaxed(CMN_CC_INIT, cmn->dtc[i].base + CMN_DT_PMCCNTR);
 		cmn->dtc[i].cc_active = true;
 	} else if (type == CMN_TYPE_WP) {
-		int wp_idx = arm_cmn_wp_idx(event);
 		u64 val = CMN_EVENT_WP_VAL(event);
 		u64 mask = CMN_EVENT_WP_MASK(event);
 
 		for_each_hw_dn(hw, dn, i) {
 			void __iomem *base = dn->pmu_base + CMN_DTM_OFFSET(hw->dtm_offset);
+			int wp_idx;
+
+			wp_idx = arm_cmn_get_assigned_wp_idx(cmn, dn, event, hw);
+			if (wp_idx < 0)
+				return;
 
 			writeq_relaxed(val, base + CMN_DTM_WPn_VAL(wp_idx));
 			writeq_relaxed(mask, base + CMN_DTM_WPn_MASK(wp_idx));
@@ -1549,10 +1602,13 @@ static void arm_cmn_event_stop(struct perf_event *event, int flags)
 		i = hw->dtc_idx[0];
 		cmn->dtc[i].cc_active = false;
 	} else if (type == CMN_TYPE_WP) {
-		int wp_idx = arm_cmn_wp_idx(event);
-
 		for_each_hw_dn(hw, dn, i) {
 			void __iomem *base = dn->pmu_base + CMN_DTM_OFFSET(hw->dtm_offset);
+			int wp_idx;
+
+			wp_idx = arm_cmn_get_assigned_wp_idx(cmn, dn, event, hw);
+			if (wp_idx < 0)
+				continue;
 
 			writeq_relaxed(0, base + CMN_DTM_WPn_MASK(wp_idx));
 			writeq_relaxed(~0ULL, base + CMN_DTM_WPn_VAL(wp_idx));
@@ -1574,8 +1630,20 @@ struct arm_cmn_val {
 	bool cycles;
 };
 
-static void arm_cmn_val_add_event(struct arm_cmn *cmn, struct arm_cmn_val *val,
-				  struct perf_event *event)
+static int arm_cmn_val_find_free_wp_config(struct perf_event *event,
+					  struct arm_cmn_val *val, int dtm)
+{
+	int wp_idx = CMN_EVENT_EVENTID(event);
+
+	if (val->wp[dtm][wp_idx])
+		if (val->wp[dtm][++wp_idx])
+			return -ENOSPC;
+
+	return wp_idx;
+}
+
+static int arm_cmn_val_add_event(struct arm_cmn *cmn, struct arm_cmn_val *val,
+				 struct perf_event *event)
 {
 	struct arm_cmn_hw_event *hw = to_cmn_hw(event);
 	struct arm_cmn_node *dn;
@@ -1583,12 +1651,12 @@ static void arm_cmn_val_add_event(struct arm_cmn *cmn, struct arm_cmn_val *val,
 	int i;
 
 	if (is_software_event(event))
-		return;
+		return 0;
 
 	type = CMN_EVENT_TYPE(event);
 	if (type == CMN_TYPE_DTC) {
 		val->cycles = true;
-		return;
+		return 0;
 	}
 
 	for_each_hw_dtc_idx(hw, dtc, idx)
@@ -1605,9 +1673,14 @@ static void arm_cmn_val_add_event(struct arm_cmn *cmn, struct arm_cmn_val *val,
 		if (type != CMN_TYPE_WP)
 			continue;
 
-		wp_idx = arm_cmn_wp_idx(event);
+		wp_idx = arm_cmn_val_find_free_wp_config(event, val, dtm);
+		if (wp_idx < 0)
+			return -ENOSPC;
+
 		val->wp[dtm][wp_idx] = CMN_EVENT_WP_COMBINE(event) + 1;
 	}
+
+	return 0;
 }
 
 static int arm_cmn_validate_group(struct arm_cmn *cmn, struct perf_event *event)
@@ -1629,9 +1702,15 @@ static int arm_cmn_validate_group(struct arm_cmn *cmn, struct perf_event *event)
 	if (!val)
 		return -ENOMEM;
 
-	arm_cmn_val_add_event(cmn, val, leader);
-	for_each_sibling_event(sibling, leader)
-		arm_cmn_val_add_event(cmn, val, sibling);
+	ret = arm_cmn_val_add_event(cmn, val, leader);
+	if (ret)
+		goto done;
+
+	for_each_sibling_event(sibling, leader) {
+		ret = arm_cmn_val_add_event(cmn, val, sibling);
+		if (ret)
+			goto done;
+	}
 
 	type = CMN_EVENT_TYPE(event);
 	if (type == CMN_TYPE_DTC) {
@@ -1656,8 +1735,8 @@ static int arm_cmn_validate_group(struct arm_cmn *cmn, struct perf_event *event)
 		if (type != CMN_TYPE_WP)
 			continue;
 
-		wp_idx = arm_cmn_wp_idx(event);
-		if (val->wp[dtm][wp_idx])
+		wp_idx = arm_cmn_val_find_free_wp_config(event, val, dtm);
+		if (wp_idx < 0)
 			goto done;
 
 		wp_cmb = val->wp[dtm][wp_idx ^ 1];
@@ -1772,8 +1851,11 @@ static void arm_cmn_event_clear(struct arm_cmn *cmn, struct perf_event *event,
 		struct arm_cmn_dtm *dtm = &cmn->dtms[hw->dn[i].dtm] + hw->dtm_offset;
 		unsigned int dtm_idx = arm_cmn_get_index(hw->dtm_idx, i);
 
-		if (type == CMN_TYPE_WP)
-			dtm->wp_event[arm_cmn_wp_idx(event)] = -1;
+		if (type == CMN_TYPE_WP) {
+			int wp_idx = arm_cmn_get_assigned_wp_idx(cmn, &hw->dn[i], event, hw);
+
+			dtm->wp_event[wp_idx] = -1;
+		}
 
 		if (hw->filter_sel > SEL_NONE)
 			hw->dn[i].occupid[hw->filter_sel].count--;
@@ -1782,6 +1864,7 @@ static void arm_cmn_event_clear(struct arm_cmn *cmn, struct perf_event *event,
 		writel_relaxed(dtm->pmu_config_low, dtm->base + CMN_DTM_PMU_CONFIG);
 	}
 	memset(hw->dtm_idx, 0, sizeof(hw->dtm_idx));
+	bitmap_zero(hw->wp_cfg, 2 * CMN_MAX_XPS);
 
 	for_each_hw_dtc_idx(hw, j, idx)
 		cmn->dtc[j].counters[idx] = NULL;
@@ -1835,10 +1918,11 @@ static int arm_cmn_event_add(struct perf_event *event, int flags)
 		if (type == CMN_TYPE_XP) {
 			input_sel = CMN__PMEVCNT0_INPUT_SEL_XP + dtm_idx;
 		} else if (type == CMN_TYPE_WP) {
-			int tmp, wp_idx = arm_cmn_wp_idx(event);
+			int tmp, wp_idx;
 			u32 cfg = arm_cmn_wp_config(event);
 
-			if (dtm->wp_event[wp_idx] >= 0)
+			wp_idx = arm_cmn_find_free_wp_idx(cmn, dtm, event);
+			if (wp_idx < 0)
 				goto free_dtms;
 
 			tmp = dtm->wp_event[wp_idx ^ 1];
@@ -1847,7 +1931,8 @@ static int arm_cmn_event_add(struct perf_event *event, int flags)
 				goto free_dtms;
 
 			input_sel = CMN__PMEVCNT0_INPUT_SEL_WP + wp_idx;
-			dtm->wp_event[wp_idx] = hw->dtc_idx[d];
+
+			arm_cmn_claim_wp_idx(cmn, dtm, event, dn, wp_idx, d);
 			writel_relaxed(cfg, dtm->base + CMN_DTM_WPn_CONFIG(wp_idx));
 		} else {
 			struct arm_cmn_nodeid nid = arm_cmn_nid(cmn, dn->id);
-- 
2.43.2