arm_pmu_platform.c

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