drivers/perf/arm_pmu_platform.c

   1 /*
   2  * platform_device probing code for ARM performance counters.
   3  *
   4  * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
   5  * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
   6  */
   7 #define pr_fmt(fmt) "hw perfevents: " fmt
   8
   9 #include <linux/bug.h>
  10 #include <linux/cpumask.h>
  11 #include <linux/device.h>
  12 #include <linux/errno.h>
  13 #include <linux/irq.h>
  14 #include <linux/irqdesc.h>
  15 #include <linux/kconfig.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/percpu.h>
  19 #include <linux/perf/arm_pmu.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/printk.h>
  22 #include <linux/smp.h>
  23
  24 static int probe_current_pmu(struct arm_pmu *pmu,
  25                              const struct pmu_probe_info *info)
  26 {
  27         int cpu = get_cpu();
  28         unsigned int cpuid = read_cpuid_id();
  29         int ret = -ENODEV;
  30
  31         pr_info("probing PMU on CPU %d\n", cpu);
  32
  33         for (; info->init != NULL; info++) {
  34                 if ((cpuid & info->mask) != info->cpuid)
  35                         continue;
  36                 ret = info->init(pmu);
  37                 break;
  38         }
  39
  40         put_cpu();
  41         return ret;
  42 }
  43
  44 static int pmu_parse_percpu_irq(struct arm_pmu *pmu, int irq)
  45 {
  46         int cpu, ret;
  47         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
  48
  49         ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
  50         if (ret)
  51                 return ret;
  52
  53         for_each_cpu(cpu, &pmu->supported_cpus)
  54                 per_cpu(hw_events->irq, cpu) = irq;
  55
  56         return 0;
  57 }
  58
  59 static bool pmu_has_irq_affinity(struct device_node *node)
  60 {
  61         return !!of_find_property(node, "interrupt-affinity", NULL);
  62 }
  63
  64 static int pmu_parse_irq_affinity(struct device_node *node, int i)
  65 {
  66         struct device_node *dn;
  67         int cpu;
  68
  69         /*
  70          * If we don't have an interrupt-affinity property, we guess irq
  71          * affinity matches our logical CPU order, as we used to assume.
  72          * This is fragile, so we'll warn in pmu_parse_irqs().
  73          */
  74         if (!pmu_has_irq_affinity(node))
  75                 return i;
  76
  77         dn = of_parse_phandle(node, "interrupt-affinity", i);
  78         if (!dn) {
  79                 pr_warn("failed to parse interrupt-affinity[%d] for %s\n",
  80                         i, node->name);
  81                 return -EINVAL;
  82         }
  83
  84         /* Now look up the logical CPU number */
  85         for_each_possible_cpu(cpu) {
  86                 struct device_node *cpu_dn;
  87
  88                 cpu_dn = of_cpu_device_node_get(cpu);
  89                 of_node_put(cpu_dn);
  90
  91                 if (dn == cpu_dn)
  92                         break;
  93         }
  94
  95         if (cpu >= nr_cpu_ids) {
  96                 pr_warn("failed to find logical CPU for %s\n", dn->name);
  97         }
  98
  99         of_node_put(dn);
 100
 101         return cpu;
 102 }
 103
 104 static int pmu_parse_irqs(struct arm_pmu *pmu)
 105 {
 106         int i = 0, num_irqs;
 107         struct platform_device *pdev = pmu->plat_device;
 108         struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
 109
 110         num_irqs = platform_irq_count(pdev);
 111         if (num_irqs < 0) {
 112                 pr_err("unable to count PMU IRQs\n");
 113                 return num_irqs;
 114         }
 115
 116         /*
 117          * In this case we have no idea which CPUs are covered by the PMU.
 118          * To match our prior behaviour, we assume all CPUs in this case.
 119          */
 120         if (num_irqs == 0) {
 121                 pr_warn("no irqs for PMU, sampling events not supported\n");
 122                 pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 123                 cpumask_setall(&pmu->supported_cpus);
 124                 return 0;
 125         }
 126
 127         if (num_irqs == 1) {
 128                 int irq = platform_get_irq(pdev, 0);
 129                 if (irq && irq_is_percpu(irq))
 130                         return pmu_parse_percpu_irq(pmu, irq);
 131         }
 132
 133         if (!pmu_has_irq_affinity(pdev->dev.of_node)) {
 134                 pr_warn("no interrupt-affinity property for %pOF, guessing.\n",
 135                         pdev->dev.of_node);
 136         }
 137
 138         /*
 139          * Some platforms have all PMU IRQs OR'd into a single IRQ, with a
 140          * special platdata function that attempts to demux them.
 141          */
 142         if (dev_get_platdata(&pdev->dev))
 143                 cpumask_setall(&pmu->supported_cpus);
 144
 145         for (i = 0; i < num_irqs; i++) {
 146                 int cpu, irq;
 147
 148                 irq = platform_get_irq(pdev, i);
 149                 if (WARN_ON(irq <= 0))
 150                         continue;
 151
 152                 if (irq_is_percpu(irq)) {
 153                         pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
 154                         return -EINVAL;
 155                 }
 156
 157                 cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
 158                 if (cpu < 0)
 159                         return cpu;
 160                 if (cpu >= nr_cpu_ids)
 161                         continue;
 162
 163                 if (per_cpu(hw_events->irq, cpu)) {
 164                         pr_warn("multiple PMU IRQs for the same CPU detected\n");
 165                         return -EINVAL;
 166                 }
 167
 168                 per_cpu(hw_events->irq, cpu) = irq;
 169                 cpumask_set_cpu(cpu, &pmu->supported_cpus);
 170         }
 171
 172         return 0;
 173 }
 174
 175 int arm_pmu_device_probe(struct platform_device *pdev,
 176                          const struct of_device_id *of_table,
 177                          const struct pmu_probe_info *probe_table)
 178 {
 179         const struct of_device_id *of_id;
 180         armpmu_init_fn init_fn;
 181         struct device_node *node = pdev->dev.of_node;
 182         struct arm_pmu *pmu;
 183         int ret = -ENODEV;
 184
 185         pmu = armpmu_alloc();
 186         if (!pmu)
 187                 return -ENOMEM;
 188
 189         pmu->plat_device = pdev;
 190
 191         ret = pmu_parse_irqs(pmu);
 192         if (ret)
 193                 goto out_free;
 194
 195         if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
 196                 init_fn = of_id->data;
 197
 198                 pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
 199                                                            "secure-reg-access");
 200
 201                 /* arm64 systems boot only as non-secure */
 202                 if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
 203                         pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
 204                         pmu->secure_access = false;
 205                 }
 206
 207                 ret = init_fn(pmu);
 208         } else if (probe_table) {
 209                 cpumask_setall(&pmu->supported_cpus);
 210                 ret = probe_current_pmu(pmu, probe_table);
 211         }
 212
 213         if (ret) {
 214                 pr_info("%pOF: failed to probe PMU!\n", node);
 215                 goto out_free;
 216         }
 217
 218         ret = armpmu_request_irqs(pmu);
 219         if (ret)
 220                 goto out_free_irqs;
 221
 222         ret = armpmu_register(pmu);
 223         if (ret)
 224                 goto out_free;
 225
 226         return 0;
 227
 228 out_free_irqs:
 229         armpmu_free_irqs(pmu);
 230 out_free:
 231         pr_info("%pOF: failed to register PMU devices!\n", node);
 232         armpmu_free(pmu);
 233         return ret;
 234 }