arch/mips/oprofile/op_model_loongson2.c

   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/godson2"
  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
  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_enalbed, cnt2_enalbed;
  48 } reg;
  49
  50 DEFINE_SPINLOCK(sample_lock);
  51
  52 static char *oprofid = "LoongsonPerf";
  53 static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
  54 /* Compute all of the registers in preparation for enabling profiling.  */
  55
  56 static 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_enalbed = cfg[0].enabled;
  85         reg.cnt2_enalbed = cfg[1].enabled;
  86
  87 }
  88
  89 /* Program all of the registers in preparation for enabling profiling.  */
  90
  91 static 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
  99 static void loongson2_cpu_start(void *args)
 100 {
 101         /* Start all counters on current CPU */
 102         if (reg.cnt1_enalbed || reg.cnt2_enalbed)
 103                 write_c0_perfctrl(reg.ctrl);
 104 }
 105
 106 static 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
 113 static 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_enalbed | reg.cnt2_enalbed;
 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_enalbed)
 140                         oprofile_add_sample(regs, 0);
 141                 counter1 = reg.reset_counter1;
 142         }
 143         if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
 144                 if (reg.cnt2_enalbed)
 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
 156 static int __init loongson2_init(void)
 157 {
 158         return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
 159                            IRQF_SHARED, "Perfcounter", oprofid);
 160 }
 161
 162 static void loongson2_exit(void)
 163 {
 164         write_c0_perfctrl(0);
 165         free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
 166 }
 167
 168 struct 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 };