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 } 235