drivers/perf/arm_pmu_platform.c

   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 (!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         /*
 131          * Some platforms have all PMU IRQs OR'd into a single IRQ, with a
 132          * special platdata function that attempts to demux them.
 133          */
 134         if (dev_get_platdata(&pdev->dev))
 135                 cpumask_setall(&pmu->supported_cpus);
 136
 137         for (i = 0; i < num_irqs; i++) {
 138                 int cpu, irq;
 139
 140                 irq = platform_get_irq(pdev, i);
 141                 if (WARN_ON(irq <= 0))
 142                         continue;
 143
 144                 if (irq_is_percpu_devid(irq)) {
 145                         pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
 146                         return -EINVAL;
 147                 }
 148
 149                 cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
 150                 if (cpu < 0)
 151                         return cpu;
 152                 if (cpu >= nr_cpu_ids)
 153                         continue;
 154
 155                 if (per_cpu(hw_events->irq, cpu)) {
 156                         pr_warn("multiple PMU IRQs for the same CPU detected\n");
 157                         return -EINVAL;
 158                 }
 159
 160                 per_cpu(hw_events->irq, cpu) = irq;
 161                 cpumask_set_cpu(cpu, &pmu->supported_cpus);
 162         }
 163
 164         return 0;
 165 }
 166
 167 int arm_pmu_device_probe(struct platform_device *pdev,
 168                          const struct of_device_id *of_table,
 169                          const struct pmu_probe_info *probe_table)
 170 {
 171         const struct of_device_id *of_id;
 172         armpmu_init_fn init_fn;
 173         struct device_node *node = pdev->dev.of_node;
 174         struct arm_pmu *pmu;
 175         int ret = -ENODEV;
 176
 177         pmu = armpmu_alloc();
 178         if (!pmu)
 179                 return -ENOMEM;
 180
 181         pmu->plat_device = pdev;
 182
 183         ret = pmu_parse_irqs(pmu);
 184         if (ret)
 185                 goto out_free;
 186
 187         if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
 188                 init_fn = of_id->data;
 189
 190                 pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
 191                                                            "secure-reg-access");
 192
 193                 /* arm64 systems boot only as non-secure */
 194                 if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
 195                         pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
 196                         pmu->secure_access = false;
 197                 }
 198
 199                 ret = init_fn(pmu);
 200         } else if (probe_table) {
 201                 cpumask_setall(&pmu->supported_cpus);
 202                 ret = probe_current_pmu(pmu, probe_table);
 203         }
 204
 205         if (ret) {
 206                 pr_info("%pOF: failed to probe PMU!\n", node);
 207                 goto out_free;
 208         }
 209
 210         ret = armpmu_request_irqs(pmu);
 211         if (ret)
 212                 goto out_free_irqs;
 213
 214         ret = armpmu_register(pmu);
 215         if (ret)
 216                 goto out_free;
 217
 218         return 0;
 219
 220 out_free_irqs:
 221         armpmu_free_irqs(pmu);
 222 out_free:
 223         pr_info("%pOF: failed to register PMU devices!\n", node);
 224         armpmu_free(pmu);
 225         return ret;
 226 }