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247 lines · 5.5 KiB

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 <[email protected]>
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}