1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * platform_device probing code for ARM performance counters.
  4 *
  5 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
  6 * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
  7 */
  8#define pr_fmt(fmt) "hw perfevents: " fmt
  9
 10#include <linux/bug.h>
 11#include <linux/cpumask.h>
 12#include <linux/device.h>
 13#include <linux/errno.h>
 14#include <linux/irq.h>
 15#include <linux/irqdesc.h>
 16#include <linux/kconfig.h>
 17#include <linux/of.h>
 18#include <linux/of_device.h>
 19#include <linux/percpu.h>
 20#include <linux/perf/arm_pmu.h>
 21#include <linux/platform_device.h>
 22#include <linux/printk.h>
 23#include <linux/smp.h>
 24
 25static int probe_current_pmu(struct arm_pmu *pmu,
 26			     const struct pmu_probe_info *info)
 27{
 28	int cpu = get_cpu();
 29	unsigned int cpuid = read_cpuid_id();
 30	int ret = -ENODEV;
 31
 32	pr_info("probing PMU on CPU %d\n", cpu);
 33
 34	for (; info->init != NULL; info++) {
 35		if ((cpuid & info->mask) != info->cpuid)
 36			continue;
 37		ret = info->init(pmu);
 38		break;
 39	}
 40
 41	put_cpu();
 42	return ret;
 43}
 44
 45static int pmu_parse_percpu_irq(struct arm_pmu *pmu, int irq)
 46{
 47	int cpu, ret;
 48	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 49
 50	ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
 51	if (ret)
 52		return ret;
 53
 54	for_each_cpu(cpu, &pmu->supported_cpus)
 55		per_cpu(hw_events->irq, cpu) = irq;
 56
 57	return 0;
 58}
 59
 60static bool pmu_has_irq_affinity(struct device_node *node)
 61{
 62	return !!of_find_property(node, "interrupt-affinity", NULL);
 63}
 64
 65static int pmu_parse_irq_affinity(struct device_node *node, int i)
 66{
 67	struct device_node *dn;
 68	int cpu;
 69
 70	/*
 71	 * If we don't have an interrupt-affinity property, we guess irq
 72	 * affinity matches our logical CPU order, as we used to assume.
 73	 * This is fragile, so we'll warn in pmu_parse_irqs().
 74	 */
 75	if (!pmu_has_irq_affinity(node))
 76		return i;
 77
 78	dn = of_parse_phandle(node, "interrupt-affinity", i);
 79	if (!dn) {
 80		pr_warn("failed to parse interrupt-affinity[%d] for %pOFn\n",
 81			i, node);
 82		return -EINVAL;
 83	}
 84
 85	cpu = of_cpu_node_to_id(dn);
 86	if (cpu < 0) {
 87		pr_warn("failed to find logical CPU for %pOFn\n", dn);
 88		cpu = nr_cpu_ids;
 89	}
 90
 91	of_node_put(dn);
 92
 93	return cpu;
 94}
 95
 96static int pmu_parse_irqs(struct arm_pmu *pmu)
 97{
 98	int i = 0, num_irqs;
 99	struct platform_device *pdev = pmu->plat_device;
100	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
101
102	num_irqs = platform_irq_count(pdev);
103	if (num_irqs < 0) {
104		pr_err("unable to count PMU IRQs\n");
105		return num_irqs;
106	}
107
108	/*
109	 * In this case we have no idea which CPUs are covered by the PMU.
110	 * To match our prior behaviour, we assume all CPUs in this case.
111	 */
112	if (num_irqs == 0) {
113		pr_warn("no irqs for PMU, sampling events not supported\n");
114		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
115		cpumask_setall(&pmu->supported_cpus);
116		return 0;
117	}
118
119	if (num_irqs == 1) {
120		int irq = platform_get_irq(pdev, 0);
121		if (irq && irq_is_percpu_devid(irq))
122			return pmu_parse_percpu_irq(pmu, irq);
123	}
124
125	if (nr_cpu_ids != 1 && !pmu_has_irq_affinity(pdev->dev.of_node)) {
126		pr_warn("no interrupt-affinity property for %pOF, guessing.\n",
127			pdev->dev.of_node);
128	}
129
130	for (i = 0; i < num_irqs; i++) {
131		int cpu, irq;
132
133		irq = platform_get_irq(pdev, i);
134		if (WARN_ON(irq <= 0))
135			continue;
136
137		if (irq_is_percpu_devid(irq)) {
138			pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
139			return -EINVAL;
140		}
141
142		cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
143		if (cpu < 0)
144			return cpu;
145		if (cpu >= nr_cpu_ids)
146			continue;
147
148		if (per_cpu(hw_events->irq, cpu)) {
149			pr_warn("multiple PMU IRQs for the same CPU detected\n");
150			return -EINVAL;
151		}
152
153		per_cpu(hw_events->irq, cpu) = irq;
154		cpumask_set_cpu(cpu, &pmu->supported_cpus);
155	}
156
157	return 0;
158}
159
160static int armpmu_request_irqs(struct arm_pmu *armpmu)
161{
162	struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
163	int cpu, err = 0;
164
165	for_each_cpu(cpu, &armpmu->supported_cpus) {
166		int irq = per_cpu(hw_events->irq, cpu);
167		if (!irq)
168			continue;
169
170		err = armpmu_request_irq(irq, cpu);
171		if (err)
172			break;
173	}
174
175	return err;
176}
177
178static void armpmu_free_irqs(struct arm_pmu *armpmu)
179{
180	int cpu;
181	struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
182
183	for_each_cpu(cpu, &armpmu->supported_cpus) {
184		int irq = per_cpu(hw_events->irq, cpu);
185
186		armpmu_free_irq(irq, cpu);
187	}
188}
189
190int arm_pmu_device_probe(struct platform_device *pdev,
191			 const struct of_device_id *of_table,
192			 const struct pmu_probe_info *probe_table)
193{
194	const struct of_device_id *of_id;
195	armpmu_init_fn init_fn;
196	struct device_node *node = pdev->dev.of_node;
197	struct arm_pmu *pmu;
198	int ret = -ENODEV;
199
200	pmu = armpmu_alloc();
201	if (!pmu)
202		return -ENOMEM;
203
204	pmu->plat_device = pdev;
205
206	ret = pmu_parse_irqs(pmu);
207	if (ret)
208		goto out_free;
209
210	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
211		init_fn = of_id->data;
212
213		pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
214							   "secure-reg-access");
215
216		/* arm64 systems boot only as non-secure */
217		if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
218			pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
219			pmu->secure_access = false;
220		}
221
222		ret = init_fn(pmu);
223	} else if (probe_table) {
224		cpumask_setall(&pmu->supported_cpus);
225		ret = probe_current_pmu(pmu, probe_table);
226	}
227
228	if (ret) {
229		pr_info("%pOF: failed to probe PMU!\n", node);
230		goto out_free;
231	}
232
233	ret = armpmu_request_irqs(pmu);
234	if (ret)
235		goto out_free_irqs;
236
237	ret = armpmu_register(pmu);
238	if (ret)
239		goto out_free;
240
241	return 0;
242
243out_free_irqs:
244	armpmu_free_irqs(pmu);
245out_free:
246	pr_info("%pOF: failed to register PMU devices!\n", node);
247	armpmu_free(pmu);
248	return ret;
249}