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   1 /*
   2  * AVR32 Performance Counter Driver
   3  *
   4  * Copyright (C) 2005-2007 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Author: Ronny Pedersen
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irq.h>
  15 #include <linux/oprofile.h>
  16 #include <linux/sched.h>
  17 #include <linux/types.h>
  18
  19 #include <asm/sysreg.h>
  20 #include <asm/system.h>
  21
  22 #define AVR32_PERFCTR_IRQ_GROUP 0
  23 #define AVR32_PERFCTR_IRQ_LINE  1
  24
  25 enum { PCCNT, PCNT0, PCNT1, NR_counter };
  26
  27 struct avr32_perf_counter {
  28         unsigned long   enabled;
  29         unsigned long   event;
  30         unsigned long   count;
  31         unsigned long   unit_mask;
  32         unsigned long   kernel;
  33         unsigned long   user;
  34
  35         u32             ie_mask;
  36         u32             flag_mask;
  37 };
  38
  39 static struct avr32_perf_counter counter[NR_counter] = {
  40         {
  41                 .ie_mask        = SYSREG_BIT(IEC),
  42                 .flag_mask      = SYSREG_BIT(FC),
  43         }, {
  44                 .ie_mask        = SYSREG_BIT(IE0),
  45                 .flag_mask      = SYSREG_BIT(F0),
  46         }, {
  47                 .ie_mask        = SYSREG_BIT(IE1),
  48                 .flag_mask      = SYSREG_BIT(F1),
  49         },
  50 };
  51
  52 static void avr32_perf_counter_reset(void)
  53 {
  54         /* Reset all counter and disable/clear all interrupts */
  55         sysreg_write(PCCR, (SYSREG_BIT(PCCR_R)
  56                                 | SYSREG_BIT(PCCR_C)
  57                                 | SYSREG_BIT(FC)
  58                                 | SYSREG_BIT(F0)
  59                                 | SYSREG_BIT(F1)));
  60 }
  61
  62 static irqreturn_t avr32_perf_counter_interrupt(int irq, void *dev_id)
  63 {
  64         struct avr32_perf_counter *ctr = dev_id;
  65         struct pt_regs *regs;
  66         u32 pccr;
  67
  68         if (likely(!(intc_get_pending(AVR32_PERFCTR_IRQ_GROUP)
  69                                         & (1 << AVR32_PERFCTR_IRQ_LINE))))
  70                 return IRQ_NONE;
  71
  72         regs = get_irq_regs();
  73         pccr = sysreg_read(PCCR);
  74
  75         /* Clear the interrupt flags we're about to handle */
  76         sysreg_write(PCCR, pccr);
  77
  78         /* PCCNT */
  79         if (ctr->enabled && (pccr & ctr->flag_mask)) {
  80                 sysreg_write(PCCNT, -ctr->count);
  81                 oprofile_add_sample(regs, PCCNT);
  82         }
  83         ctr++;
  84         /* PCNT0 */
  85         if (ctr->enabled && (pccr & ctr->flag_mask)) {
  86                 sysreg_write(PCNT0, -ctr->count);
  87                 oprofile_add_sample(regs, PCNT0);
  88         }
  89         ctr++;
  90         /* PCNT1 */
  91         if (ctr->enabled && (pccr & ctr->flag_mask)) {
  92                 sysreg_write(PCNT1, -ctr->count);
  93                 oprofile_add_sample(regs, PCNT1);
  94         }
  95
  96         return IRQ_HANDLED;
  97 }
  98
  99 static int avr32_perf_counter_create_files(struct super_block *sb,
 100                 struct dentry *root)
 101 {
 102         struct dentry *dir;
 103         unsigned int i;
 104         char filename[4];
 105
 106         for (i = 0; i < NR_counter; i++) {
 107                 snprintf(filename, sizeof(filename), "%u", i);
 108                 dir = oprofilefs_mkdir(sb, root, filename);
 109
 110                 oprofilefs_create_ulong(sb, dir, "enabled",
 111                                 &counter[i].enabled);
 112                 oprofilefs_create_ulong(sb, dir, "event",
 113                                 &counter[i].event);
 114                 oprofilefs_create_ulong(sb, dir, "count",
 115                                 &counter[i].count);
 116
 117                 /* Dummy entries */
 118                 oprofilefs_create_ulong(sb, dir, "kernel",
 119                                 &counter[i].kernel);
 120                 oprofilefs_create_ulong(sb, dir, "user",
 121                                 &counter[i].user);
 122                 oprofilefs_create_ulong(sb, dir, "unit_mask",
 123                                 &counter[i].unit_mask);
 124         }
 125
 126         return 0;
 127 }
 128
 129 static int avr32_perf_counter_setup(void)
 130 {
 131         struct avr32_perf_counter *ctr;
 132         u32 pccr;
 133         int ret;
 134         int i;
 135
 136         pr_debug("avr32_perf_counter_setup\n");
 137
 138         if (sysreg_read(PCCR) & SYSREG_BIT(PCCR_E)) {
 139                 printk(KERN_ERR
 140                         "oprofile: setup: perf counter already enabled\n");
 141                 return -EBUSY;
 142         }
 143
 144         ret = request_irq(AVR32_PERFCTR_IRQ_GROUP,
 145                         avr32_perf_counter_interrupt, IRQF_SHARED,
 146                         "oprofile", counter);
 147         if (ret)
 148                 return ret;
 149
 150         avr32_perf_counter_reset();
 151
 152         pccr = 0;
 153         for (i = PCCNT; i < NR_counter; i++) {
 154                 ctr = &counter[i];
 155                 if (!ctr->enabled)
 156                         continue;
 157
 158                 pr_debug("enabling counter %d...\n", i);
 159
 160                 pccr |= ctr->ie_mask;
 161
 162                 switch (i) {
 163                 case PCCNT:
 164                         /* PCCNT always counts cycles, so no events */
 165                         sysreg_write(PCCNT, -ctr->count);
 166                         break;
 167                 case PCNT0:
 168                         pccr |= SYSREG_BF(CONF0, ctr->event);
 169                         sysreg_write(PCNT0, -ctr->count);
 170                         break;
 171                 case PCNT1:
 172                         pccr |= SYSREG_BF(CONF1, ctr->event);
 173                         sysreg_write(PCNT1, -ctr->count);
 174                         break;
 175                 }
 176         }
 177
 178         pr_debug("oprofile: writing 0x%x to PCCR...\n", pccr);
 179
 180         sysreg_write(PCCR, pccr);
 181
 182         return 0;
 183 }
 184
 185 static void avr32_perf_counter_shutdown(void)
 186 {
 187         pr_debug("avr32_perf_counter_shutdown\n");
 188
 189         avr32_perf_counter_reset();
 190         free_irq(AVR32_PERFCTR_IRQ_GROUP, counter);
 191 }
 192
 193 static int avr32_perf_counter_start(void)
 194 {
 195         pr_debug("avr32_perf_counter_start\n");
 196
 197         sysreg_write(PCCR, sysreg_read(PCCR) | SYSREG_BIT(PCCR_E));
 198
 199         return 0;
 200 }
 201
 202 static void avr32_perf_counter_stop(void)
 203 {
 204         pr_debug("avr32_perf_counter_stop\n");
 205
 206         sysreg_write(PCCR, sysreg_read(PCCR) & ~SYSREG_BIT(PCCR_E));
 207 }
 208
 209 static struct oprofile_operations avr32_perf_counter_ops __initdata = {
 210         .create_files   = avr32_perf_counter_create_files,
 211         .setup          = avr32_perf_counter_setup,
 212         .shutdown       = avr32_perf_counter_shutdown,
 213         .start          = avr32_perf_counter_start,
 214         .stop           = avr32_perf_counter_stop,
 215         .cpu_type       = "avr32",
 216 };
 217
 218 int __init oprofile_arch_init(struct oprofile_operations *ops)
 219 {
 220         if (!(current_cpu_data.features & AVR32_FEATURE_PCTR))
 221                 return -ENODEV;
 222
 223         memcpy(ops, &avr32_perf_counter_ops,
 224                         sizeof(struct oprofile_operations));
 225
 226         printk(KERN_INFO "oprofile: using AVR32 performance monitoring.\n");
 227
 228         return 0;
 229 }
 230
 231 void oprofile_arch_exit(void)
 232 {
 233
 234 }