driver/gator_events_mmaped.c

   1 /*
   2  * Example events provider
   3  *
   4  * Copyright (C) ARM Limited 2010-2012. All rights reserved.
   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  * Similar entries to those below must be present in the events.xml file.
  11  * To add them to the events.xml, create an events-mmap.xml with the
  12  * following contents and rebuild gatord:
  13  *
  14  * <counter_set name="mmaped_cnt" count="3"/>
  15  * <category name="mmaped" counter_set="mmaped_cnt" per_cpu="no">
  16  *   <event event="0x0" title="Simulated" name="Sine" display="maximum" average_selection="yes" description="Sort-of-sine"/>
  17  *   <event event="0x1" title="Simulated" name="Triangle" display="maximum" average_selection="yes" description="Triangular wave"/>
  18  *   <event event="0x2" title="Simulated" name="PWM" display="maximum" average_selection="yes" description="PWM Signal"/>
  19  * </category>
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/io.h>
  24 #include <linux/ratelimit.h>
  25
  26 #include "gator.h"
  27
  28 #define MMAPED_COUNTERS_NUM 3
  29
  30 static struct {
  31         unsigned long enabled;
  32         unsigned long event;
  33         unsigned long key;
  34 } mmaped_counters[MMAPED_COUNTERS_NUM];
  35
  36 static int mmaped_buffer[MMAPED_COUNTERS_NUM * 2];
  37
  38 #ifdef TODO
  39 static void __iomem *mmaped_base;
  40 #endif
  41
  42 #ifndef TODO
  43 static s64 prev_time;
  44 #endif
  45
  46 /* Adds mmaped_cntX directories and enabled, event, and key files to /dev/gator/events */
  47 static int gator_events_mmaped_create_files(struct super_block *sb,
  48                 struct dentry *root)
  49 {
  50         int i;
  51
  52         for (i = 0; i < MMAPED_COUNTERS_NUM; i++) {
  53                 char buf[16];
  54                 struct dentry *dir;
  55
  56                 snprintf(buf, sizeof(buf), "mmaped_cnt%d", i);
  57                 dir = gatorfs_mkdir(sb, root, buf);
  58                 if (WARN_ON(!dir))
  59                         return -1;
  60                 gatorfs_create_ulong(sb, dir, "enabled",
  61                                 &mmaped_counters[i].enabled);
  62                 gatorfs_create_ulong(sb, dir, "event",
  63                                 &mmaped_counters[i].event);
  64                 gatorfs_create_ro_ulong(sb, dir, "key",
  65                                 &mmaped_counters[i].key);
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int gator_events_mmaped_start(void)
  72 {
  73 #ifdef TODO
  74         for (i = 0; i < MMAPED_COUNTERS_NUM; i++)
  75                 writel(mmaped_counters[i].event,
  76                                 mmaped_base + COUNTERS_CONFIG_OFFSET[i]);
  77
  78         writel(ENABLED, COUNTERS_CONTROL_OFFSET);
  79 #endif
  80
  81 #ifndef TODO
  82         struct timespec ts;
  83         getnstimeofday(&ts);
  84         prev_time = timespec_to_ns(&ts);
  85 #endif
  86
  87         return 0;
  88 }
  89
  90 static void gator_events_mmaped_stop(void)
  91 {
  92 #ifdef TODO
  93         writel(DISABLED, COUNTERS_CONTROL_OFFSET);
  94 #endif
  95 }
  96
  97 #ifndef TODO
  98 /* This function "simulates" counters, generating values of fancy
  99  * functions like sine or triangle... */
 100 static int mmaped_simulate(int counter, int delta_in_us)
 101 {
 102         int result = 0;
 103
 104         switch (counter) {
 105         case 0: /* sort-of-sine */
 106                 {
 107                         static int t = 0;
 108                         int x;
 109
 110                         t += delta_in_us;
 111                         if (t > 2048000)
 112                                 t = 0;
 113
 114                         if (t % 1024000 < 512000)
 115                                 x = 512000 - (t % 512000);
 116                         else
 117                                 x = t % 512000;
 118
 119                         result = 32 * x / 512000;
 120                         result = result * result;
 121
 122                         if (t < 1024000)
 123                                 result = 1922 - result;
 124                 }
 125                 break;
 126         case 1: /* triangle */
 127                 {
 128                         static int v, d = 1;
 129
 130                         v = v + d * delta_in_us;
 131                         if (v < 0) {
 132                                 v = 0;
 133                                 d = 1;
 134                         } else if (v > 1000000) {
 135                                 v = 1000000;
 136                                 d = -1;
 137                         }
 138
 139                         result = v;
 140                 }
 141                 break;
 142         case 2: /* PWM signal */
 143                 {
 144                         static int t, dc, x;
 145
 146                         t += delta_in_us;
 147                         if (t > 1000000)
 148                                 t = 0;
 149                         if (x / 1000000 != (x + delta_in_us) / 1000000)
 150                                 dc = (dc + 100000) % 1000000;
 151                         x += delta_in_us;
 152
 153                         result = t < dc ? 0 : 10;
 154                 }
 155                 break;
 156         }
 157
 158         return result;
 159 }
 160 #endif
 161
 162 static int gator_events_mmaped_read(int **buffer)
 163 {
 164         int i;
 165         int len = 0;
 166 #ifndef TODO
 167         int delta_in_us;
 168         struct timespec ts;
 169         s64 time;
 170 #endif
 171
 172         /* System wide counters - read from one core only */
 173         if (smp_processor_id())
 174                 return 0;
 175
 176 #ifndef TODO
 177         getnstimeofday(&ts);
 178         time = timespec_to_ns(&ts);
 179         delta_in_us = (int)(time - prev_time) / 1000;
 180         prev_time = time;
 181 #endif
 182
 183         for (i = 0; i < MMAPED_COUNTERS_NUM; i++) {
 184                 if (mmaped_counters[i].enabled) {
 185                         mmaped_buffer[len++] = mmaped_counters[i].key;
 186 #ifdef TODO
 187                         mmaped_buffer[len++] = readl(mmaped_base +
 188                                         COUNTERS_VALUE_OFFSET[i]);
 189 #else
 190                         mmaped_buffer[len++] = mmaped_simulate(
 191                                         mmaped_counters[i].event, delta_in_us);
 192 #endif
 193                 }
 194         }
 195
 196         if (buffer)
 197                 *buffer = mmaped_buffer;
 198
 199         return len;
 200 }
 201
 202 static struct gator_interface gator_events_mmaped_interface = {
 203         .create_files = gator_events_mmaped_create_files,
 204         .start = gator_events_mmaped_start,
 205         .stop = gator_events_mmaped_stop,
 206         .read = gator_events_mmaped_read,
 207 };
 208
 209 /* Must not be static! */
 210 int __init gator_events_mmaped_init(void)
 211 {
 212         int i;
 213
 214 #ifdef TODO
 215         mmaped_base = ioremap(COUNTERS_PHYS_ADDR, SZ_4K);
 216         if (!mmaped_base)
 217                 return -ENOMEM;
 218 #endif
 219
 220         for (i = 0; i < MMAPED_COUNTERS_NUM; i++) {
 221                 mmaped_counters[i].enabled = 0;
 222                 mmaped_counters[i].key = gator_events_get_key();
 223         }
 224
 225         return gator_events_install(&gator_events_mmaped_interface);
 226 }
 227 gator_events_init(gator_events_mmaped_init);