LXR linux/arch/mips/oprofile/op_model

   1/*
   2 * Loongson2 performance counter driver for oprofile
   3 *
   4 * Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
   5 * Author: Yanhua <yanh@lemote.com>
   6 * Author: Wu Zhangjin <wuzj@lemote.com>
   7 *
   8 * This file is subject to the terms and conditions of the GNU General Public
   9 * License.  See the file "COPYING" in the main directory of this archive
  10 * for more details.
  11 *
  12 */
  13#include <linux/init.h>
  14#include <linux/oprofile.h>
  15#include <linux/interrupt.h>
  16
  17#include <loongson.h>                   /* LOONGSON2_PERFCNT_IRQ */
  18#include "op_impl.h"
  19
  20/*
  21 * a patch should be sent to oprofile with the loongson-specific support.
  22 * otherwise, the oprofile tool will not recognize this and complain about
  23 * "cpu_type 'unset' is not valid".
  24 */
  25#define LOONGSON2_CPU_TYPE      "mips/loongson2"
  26
  27#define LOONGSON2_COUNTER1_EVENT(event) ((event & 0x0f) << 5)
  28#define LOONGSON2_COUNTER2_EVENT(event) ((event & 0x0f) << 9)
  29
  30#define LOONGSON2_PERFCNT_EXL                   (1UL    <<  0)
  31#define LOONGSON2_PERFCNT_KERNEL                (1UL    <<  1)
  32#define LOONGSON2_PERFCNT_SUPERVISOR    (1UL    <<  2)
  33#define LOONGSON2_PERFCNT_USER                  (1UL    <<  3)
  34#define LOONGSON2_PERFCNT_INT_EN                (1UL    <<  4)
  35#define LOONGSON2_PERFCNT_OVERFLOW              (1ULL   << 31)
  36
  37/* Loongson2 performance counter register */
  38#define read_c0_perfctrl() __read_64bit_c0_register($24, 0)
  39#define write_c0_perfctrl(val) __write_64bit_c0_register($24, 0, val)
  40#define read_c0_perfcnt() __read_64bit_c0_register($25, 0)
  41#define write_c0_perfcnt(val) __write_64bit_c0_register($25, 0, val)
  42
  43static struct loongson2_register_config {
  44        unsigned int ctrl;
  45        unsigned long long reset_counter1;
  46        unsigned long long reset_counter2;
  47        int cnt1_enabled, cnt2_enabled;
  48} reg;
  49
  50DEFINE_SPINLOCK(sample_lock);
  51
  52static char *oprofid = "LoongsonPerf";
  53static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
  54/* Compute all of the registers in preparation for enabling profiling.  */
  55
  56static void loongson2_reg_setup(struct op_counter_config *cfg)
  57{
  58        unsigned int ctrl = 0;
  59
  60        reg.reset_counter1 = 0;
  61        reg.reset_counter2 = 0;
  62        /* Compute the performance counter ctrl word.  */
  63        /* For now count kernel and user mode */
  64        if (cfg[0].enabled) {
  65                ctrl |= LOONGSON2_COUNTER1_EVENT(cfg[0].event);
  66                reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
  67        }
  68
  69        if (cfg[1].enabled) {
  70                ctrl |= LOONGSON2_COUNTER2_EVENT(cfg[1].event);
  71                reg.reset_counter2 = (0x80000000ULL - cfg[1].count);
  72        }
  73
  74        if (cfg[0].enabled || cfg[1].enabled) {
  75                ctrl |= LOONGSON2_PERFCNT_EXL | LOONGSON2_PERFCNT_INT_EN;
  76                if (cfg[0].kernel || cfg[1].kernel)
  77                        ctrl |= LOONGSON2_PERFCNT_KERNEL;
  78                if (cfg[0].user || cfg[1].user)
  79                        ctrl |= LOONGSON2_PERFCNT_USER;
  80        }
  81
  82        reg.ctrl = ctrl;
  83
  84        reg.cnt1_enabled = cfg[0].enabled;
  85        reg.cnt2_enabled = cfg[1].enabled;
  86
  87}
  88
  89/* Program all of the registers in preparation for enabling profiling.  */
  90
  91static void loongson2_cpu_setup(void *args)
  92{
  93        uint64_t perfcount;
  94
  95        perfcount = (reg.reset_counter2 << 32) | reg.reset_counter1;
  96        write_c0_perfcnt(perfcount);
  97}
  98
  99static void loongson2_cpu_start(void *args)
 100{
 101        /* Start all counters on current CPU */
 102        if (reg.cnt1_enabled || reg.cnt2_enabled)
 103                write_c0_perfctrl(reg.ctrl);
 104}
 105
 106static void loongson2_cpu_stop(void *args)
 107{
 108        /* Stop all counters on current CPU */
 109        write_c0_perfctrl(0);
 110        memset(&reg, 0, sizeof(reg));
 111}
 112
 113static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
 114{
 115        uint64_t counter, counter1, counter2;
 116        struct pt_regs *regs = get_irq_regs();
 117        int enabled;
 118        unsigned long flags;
 119
 120        /*
 121         * LOONGSON2 defines two 32-bit performance counters.
 122         * To avoid a race updating the registers we need to stop the counters
 123         * while we're messing with
 124         * them ...
 125         */
 126
 127        /* Check whether the irq belongs to me */
 128        enabled = reg.cnt1_enabled | reg.cnt2_enabled;
 129        if (!enabled)
 130                return IRQ_NONE;
 131
 132        counter = read_c0_perfcnt();
 133        counter1 = counter & 0xffffffff;
 134        counter2 = counter >> 32;
 135
 136        spin_lock_irqsave(&sample_lock, flags);
 137
 138        if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
 139                if (reg.cnt1_enabled)
 140                        oprofile_add_sample(regs, 0);
 141                counter1 = reg.reset_counter1;
 142        }
 143        if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
 144                if (reg.cnt2_enabled)
 145                        oprofile_add_sample(regs, 1);
 146                counter2 = reg.reset_counter2;
 147        }
 148
 149        spin_unlock_irqrestore(&sample_lock, flags);
 150
 151        write_c0_perfcnt((counter2 << 32) | counter1);
 152
 153        return IRQ_HANDLED;
 154}
 155
 156static int __init loongson2_init(void)
 157{
 158        return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
 159                           IRQF_SHARED, "Perfcounter", oprofid);
 160}
 161
 162static void loongson2_exit(void)
 163{
 164        write_c0_perfctrl(0);
 165        free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
 166}
 167
 168struct op_mips_model op_model_loongson2_ops = {
 169        .reg_setup = loongson2_reg_setup,
 170        .cpu_setup = loongson2_cpu_setup,
 171        .init = loongson2_init,
 172        .exit = loongson2_exit,
 173        .cpu_start = loongson2_cpu_start,
 174        .cpu_stop = loongson2_cpu_stop,
 175        .cpu_type = LOONGSON2_CPU_TYPE,
 176        .num_counters = 2
 177};
 178