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 
25 static 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 
45 static 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 
60 static bool pmu_has_irq_affinity(struct device_node *node)
61 {
62 	return !!of_find_property(node, "interrupt-affinity", NULL);
63 }
64 
65 static 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 %s\n",
81 			i, node->name);
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 %s\n", dn->name);
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 
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 
160 static int armpmu_request_irqs(struct arm_pmu *armpmu)
161 {
162 	struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
163 	int cpu, err;
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 
178 static 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 
190 int 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 
243 out_free_irqs:
244 	armpmu_free_irqs(pmu);
245 out_free:
246 	pr_info("%pOF: failed to register PMU devices!\n", node);
247 	armpmu_free(pmu);
248 	return ret;
249 }
250