arch/arm/kernel/pmu.c

   1 /*
   2  *  linux/arch/arm/kernel/pmu.c
   3  *
   4  *  Copyright (C) 2009 picoChip Designs Ltd, Jamie Iles
   5  *  Copyright (C) 2010 ARM Ltd, Will Deacon
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #define pr_fmt(fmt) "PMU: " fmt
  14
  15 #include <linux/cpumask.h>
  16 #include <linux/err.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/of_device.h>
  21 #include <linux/platform_device.h>
  22
  23 #include <asm/pmu.h>
  24
  25 static volatile long pmu_lock;
  26
  27 static struct platform_device *pmu_devices[ARM_NUM_PMU_DEVICES];
  28
  29 static int __devinit pmu_register(struct platform_device *pdev,
  30                                         enum arm_pmu_type type)
  31 {
  32         if (type < 0 || type >= ARM_NUM_PMU_DEVICES) {
  33                 pr_warning("received registration request for unknown "
  34                                 "device %d\n", type);
  35                 return -EINVAL;
  36         }
  37
  38         if (pmu_devices[type]) {
  39                 pr_warning("rejecting duplicate registration of PMU device "
  40                         "type %d.", type);
  41                 return -ENOSPC;
  42         }
  43
  44         pr_info("registered new PMU device of type %d\n", type);
  45         pmu_devices[type] = pdev;
  46         return 0;
  47 }
  48
  49 #define OF_MATCH_PMU(_name, _type) {    \
  50         .compatible = _name,            \
  51         .data = (void *)_type,          \
  52 }
  53
  54 #define OF_MATCH_CPU(name)      OF_MATCH_PMU(name, ARM_PMU_DEVICE_CPU)
  55
  56 static struct of_device_id armpmu_of_device_ids[] = {
  57         OF_MATCH_CPU("arm,cortex-a9-pmu"),
  58         OF_MATCH_CPU("arm,cortex-a8-pmu"),
  59         OF_MATCH_CPU("arm,arm1136-pmu"),
  60         OF_MATCH_CPU("arm,arm1176-pmu"),
  61         {},
  62 };
  63
  64 enum arm_pmu_type armpmu_device_type(struct platform_device *pdev)
  65 {
  66         const struct of_device_id       *of_id;
  67
  68         /* provided by of_device_id table */
  69         if (pdev->dev.of_node) {
  70                 of_id = of_match_device(armpmu_of_device_ids, &pdev->dev);
  71                 BUG_ON(!of_id);
  72                 return (enum arm_pmu_type)of_id->data;
  73         }
  74
  75         /* Provided by a 'legacy' platform_device */
  76         return ARM_PMU_DEVICE_CPU;
  77 }
  78
  79 static int __devinit armpmu_device_probe(struct platform_device *pdev)
  80 {
  81         return pmu_register(pdev, armpmu_device_type(pdev));
  82 }
  83
  84 static struct platform_driver armpmu_driver = {
  85         .driver         = {
  86                 .name   = "arm-pmu",
  87                 .of_match_table = armpmu_of_device_ids,
  88         },
  89         .probe          = armpmu_device_probe,
  90 };
  91
  92 static int __init register_pmu_driver(void)
  93 {
  94         return platform_driver_register(&armpmu_driver);
  95 }
  96 device_initcall(register_pmu_driver);
  97
  98 struct platform_device *
  99 reserve_pmu(enum arm_pmu_type device)
 100 {
 101         struct platform_device *pdev;
 102
 103         if (test_and_set_bit_lock(device, &pmu_lock)) {
 104                 pdev = ERR_PTR(-EBUSY);
 105         } else if (pmu_devices[device] == NULL) {
 106                 clear_bit_unlock(device, &pmu_lock);
 107                 pdev = ERR_PTR(-ENODEV);
 108         } else {
 109                 pdev = pmu_devices[device];
 110         }
 111
 112         return pdev;
 113 }
 114 EXPORT_SYMBOL_GPL(reserve_pmu);
 115
 116 int
 117 release_pmu(enum arm_pmu_type device)
 118 {
 119         if (WARN_ON(!pmu_devices[device]))
 120                 return -EINVAL;
 121         clear_bit_unlock(device, &pmu_lock);
 122         return 0;
 123 }
 124 EXPORT_SYMBOL_GPL(release_pmu);
 125
 126 static int
 127 set_irq_affinity(int irq,
 128                  unsigned int cpu)
 129 {
 130 #ifdef CONFIG_SMP
 131         int err = irq_set_affinity(irq, cpumask_of(cpu));
 132         if (err)
 133                 pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
 134                            irq, cpu);
 135         return err;
 136 #else
 137         return -EINVAL;
 138 #endif
 139 }
 140
 141 static int
 142 init_cpu_pmu(void)
 143 {
 144         int i, irqs, err = 0;
 145         struct platform_device *pdev = pmu_devices[ARM_PMU_DEVICE_CPU];
 146
 147         if (!pdev)
 148                 return -ENODEV;
 149
 150         irqs = pdev->num_resources;
 151
 152         /*
 153          * If we have a single PMU interrupt that we can't shift, assume that
 154          * we're running on a uniprocessor machine and continue.
 155          */
 156         if (irqs == 1 && !irq_can_set_affinity(platform_get_irq(pdev, 0)))
 157                 return 0;
 158
 159         for (i = 0; i < irqs; ++i) {
 160                 err = set_irq_affinity(platform_get_irq(pdev, i), i);
 161                 if (err)
 162                         break;
 163         }
 164
 165         return err;
 166 }
 167
 168 int
 169 init_pmu(enum arm_pmu_type device)
 170 {
 171         int err = 0;
 172
 173         switch (device) {
 174         case ARM_PMU_DEVICE_CPU:
 175                 err = init_cpu_pmu();
 176                 break;
 177         default:
 178                 pr_warning("attempt to initialise unknown device %d\n",
 179                                 device);
 180                 err = -EINVAL;
 181         }
 182
 183         return err;
 184 }
 185 EXPORT_SYMBOL_GPL(init_pmu);