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