arch/mips/oprofile/op_model_loongson2.c

   1 /*
   2  * Loongson2 performance counter driver for oprofile
   3  *
   4  * Copyright (C) 2009 Lemote Inc.
   5  * Author: Yanhua <yanh@lemote.com>
   6  * Author: Wu Zhangjin <wuzhangjin@gmail.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_PERFCNT_OVERFLOW              (1ULL   << 31)
  28
  29 #define LOONGSON2_PERFCTRL_EXL                  (1UL    <<  0)
  30 #define LOONGSON2_PERFCTRL_KERNEL               (1UL    <<  1)
  31 #define LOONGSON2_PERFCTRL_SUPERVISOR           (1UL    <<  2)
  32 #define LOONGSON2_PERFCTRL_USER                 (1UL    <<  3)
  33 #define LOONGSON2_PERFCTRL_ENABLE               (1UL    <<  4)
  34 #define LOONGSON2_PERFCTRL_EVENT(idx, event) \
  35         (((event) & 0x0f) << ((idx) ? 9 : 5))
  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
  43 static 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
  50 static char *oprofid = "LoongsonPerf";
  51 static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
  52 /* Compute all of the registers in preparation for enabling profiling.  */
  53
  54 static void loongson2_reg_setup(struct op_counter_config *cfg)
  55 {
  56         unsigned int ctrl = 0;
  57
  58         reg.reset_counter1 = 0;
  59         reg.reset_counter2 = 0;
  60         /* Compute the performance counter ctrl word.  */
  61         /* For now count kernel and user mode */
  62         if (cfg[0].enabled) {
  63                 ctrl |= LOONGSON2_PERFCTRL_EVENT(0, cfg[0].event);
  64                 reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
  65         }
  66
  67         if (cfg[1].enabled) {
  68                 ctrl |= LOONGSON2_PERFCTRL_EVENT(1, cfg[1].event);
  69                 reg.reset_counter2 = 0x80000000ULL - cfg[1].count;
  70         }
  71
  72         if (cfg[0].enabled || cfg[1].enabled) {
  73                 ctrl |= LOONGSON2_PERFCTRL_EXL | LOONGSON2_PERFCTRL_ENABLE;
  74                 if (cfg[0].kernel || cfg[1].kernel)
  75                         ctrl |= LOONGSON2_PERFCTRL_KERNEL;
  76                 if (cfg[0].user || cfg[1].user)
  77                         ctrl |= LOONGSON2_PERFCTRL_USER;
  78         }
  79
  80         reg.ctrl = ctrl;
  81
  82         reg.cnt1_enabled = cfg[0].enabled;
  83         reg.cnt2_enabled = cfg[1].enabled;
  84
  85 }
  86
  87 /* Program all of the registers in preparation for enabling profiling.  */
  88
  89 static void loongson2_cpu_setup(void *args)
  90 {
  91         write_c0_perfcnt((reg.reset_counter2 << 32) | reg.reset_counter1);
  92 }
  93
  94 static void loongson2_cpu_start(void *args)
  95 {
  96         /* Start all counters on current CPU */
  97         if (reg.cnt1_enabled || reg.cnt2_enabled)
  98                 write_c0_perfctrl(reg.ctrl);
  99 }
 100
 101 static void loongson2_cpu_stop(void *args)
 102 {
 103         /* Stop all counters on current CPU */
 104         write_c0_perfctrl(0);
 105         memset(&reg, 0, sizeof(reg));
 106 }
 107
 108 static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
 109 {
 110         uint64_t counter, counter1, counter2;
 111         struct pt_regs *regs = get_irq_regs();
 112         int enabled;
 113
 114         /*
 115          * LOONGSON2 defines two 32-bit performance counters.
 116          * To avoid a race updating the registers we need to stop the counters
 117          * while we're messing with
 118          * them ...
 119          */
 120
 121         /* Check whether the irq belongs to me */
 122         enabled = read_c0_perfctrl() & LOONGSON2_PERFCTRL_ENABLE;
 123         if (!enabled)
 124                 return IRQ_NONE;
 125         enabled = reg.cnt1_enabled | reg.cnt2_enabled;
 126         if (!enabled)
 127                 return IRQ_NONE;
 128
 129         counter = read_c0_perfcnt();
 130         counter1 = counter & 0xffffffff;
 131         counter2 = counter >> 32;
 132
 133         if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
 134                 if (reg.cnt1_enabled)
 135                         oprofile_add_sample(regs, 0);
 136                 counter1 = reg.reset_counter1;
 137         }
 138         if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
 139                 if (reg.cnt2_enabled)
 140                         oprofile_add_sample(regs, 1);
 141                 counter2 = reg.reset_counter2;
 142         }
 143
 144         write_c0_perfcnt((counter2 << 32) | counter1);
 145
 146         return IRQ_HANDLED;
 147 }
 148
 149 static int __init loongson2_init(void)
 150 {
 151         return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
 152                            IRQF_SHARED, "Perfcounter", oprofid);
 153 }
 154
 155 static void loongson2_exit(void)
 156 {
 157         write_c0_perfctrl(0);
 158         free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
 159 }
 160
 161 struct op_mips_model op_model_loongson2_ops = {
 162         .reg_setup = loongson2_reg_setup,
 163         .cpu_setup = loongson2_cpu_setup,
 164         .init = loongson2_init,
 165         .exit = loongson2_exit,
 166         .cpu_start = loongson2_cpu_start,
 167         .cpu_stop = loongson2_cpu_stop,
 168         .cpu_type = LOONGSON2_CPU_TYPE,
 169         .num_counters = 2
 170 };