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
26static 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
46static 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
61static bool pmu_has_irq_affinity(struct device_node *node)
62{
63	return !!of_find_property(node, "interrupt-affinity", NULL);
64}
65
66static int pmu_parse_irq_affinity(struct device_node *node, 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(node))
77		return i;
78
79	dn = of_parse_phandle(node, "interrupt-affinity", i);
80	if (!dn) {
81		pr_warn("failed to parse interrupt-affinity[%d] for %pOFn\n",
82			i, node);
83		return -EINVAL;
84	}
85
86	cpu = of_cpu_node_to_id(dn);
87	if (cpu < 0) {
88		pr_warn("failed to find logical CPU for %pOFn\n", dn);
89		cpu = nr_cpu_ids;
90	}
91
92	of_node_put(dn);
93
94	return cpu;
95}
96
97static int pmu_parse_irqs(struct arm_pmu *pmu)
98{
99	int i = 0, num_irqs;
100	struct platform_device *pdev = pmu->plat_device;
101	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
102
103	num_irqs = platform_irq_count(pdev);
104	if (num_irqs < 0)
105		return dev_err_probe(&pdev->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		pr_warn("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(pdev->dev.of_node)) {
125		pr_warn("no interrupt-affinity property for %pOF, guessing.\n",
126			pdev->dev.of_node);
127	}
128
129	for (i = 0; i < num_irqs; i++) {
130		int cpu, irq;
131
132		irq = platform_get_irq(pdev, i);
133		if (WARN_ON(irq <= 0))
134			continue;
135
136		if (irq_is_percpu_devid(irq)) {
137			pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
138			return -EINVAL;
139		}
140
141		cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
142		if (cpu < 0)
143			return cpu;
144		if (cpu >= nr_cpu_ids)
145			continue;
146
147		if (per_cpu(hw_events->irq, cpu)) {
148			pr_warn("multiple PMU IRQs for the same CPU detected\n");
149			return -EINVAL;
150		}
151
152		per_cpu(hw_events->irq, cpu) = irq;
153		cpumask_set_cpu(cpu, &pmu->supported_cpus);
154	}
155
156	return 0;
157}
158
159static int armpmu_request_irqs(struct arm_pmu *armpmu)
160{
161	struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
162	int cpu, err = 0;
163
164	for_each_cpu(cpu, &armpmu->supported_cpus) {
165		int irq = per_cpu(hw_events->irq, cpu);
166		if (!irq)
167			continue;
168
169		err = armpmu_request_irq(irq, cpu);
170		if (err)
171			break;
172	}
173
174	return err;
175}
176
177static void armpmu_free_irqs(struct arm_pmu *armpmu)
178{
179	int cpu;
180	struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
181
182	for_each_cpu(cpu, &armpmu->supported_cpus) {
183		int irq = per_cpu(hw_events->irq, cpu);
184
185		armpmu_free_irq(irq, cpu);
186	}
187}
188
189int arm_pmu_device_probe(struct platform_device *pdev,
190			 const struct of_device_id *of_table,
191			 const struct pmu_probe_info *probe_table)
192{
193	const struct of_device_id *of_id;
194	armpmu_init_fn init_fn;
195	struct device_node *node = pdev->dev.of_node;
196	struct arm_pmu *pmu;
197	int ret = -ENODEV;
198
199	pmu = armpmu_alloc();
200	if (!pmu)
201		return -ENOMEM;
202
203	pmu->plat_device = pdev;
204
205	ret = pmu_parse_irqs(pmu);
206	if (ret)
207		goto out_free;
208
209	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
210		init_fn = of_id->data;
211
212		pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
213							   "secure-reg-access");
214
215		/* arm64 systems boot only as non-secure */
216		if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
217			pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
218			pmu->secure_access = false;
219		}
220
221		ret = init_fn(pmu);
222	} else if (probe_table) {
223		cpumask_setall(&pmu->supported_cpus);
224		ret = probe_current_pmu(pmu, probe_table);
225	}
226
227	if (ret) {
228		pr_info("%pOF: failed to probe PMU!\n", node);
229		goto out_free;
230	}
231
232	ret = armpmu_request_irqs(pmu);
233	if (ret)
234		goto out_free_irqs;
235
236	ret = armpmu_register(pmu);
237	if (ret)
238		goto out_free_irqs;
239
240	return 0;
241
242out_free_irqs:
243	armpmu_free_irqs(pmu);
244out_free:
245	pr_info("%pOF: failed to register PMU devices!\n", node);
246	armpmu_free(pmu);
247	return ret;
248}
249