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 
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 
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 
61 static bool pmu_has_irq_affinity(struct device_node *node)
62 {
63 	return !!of_find_property(node, "interrupt-affinity", NULL);
64 }
65 
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 
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 
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 
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 
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