drivers/cpufreq/proc_intf.c

   1 /*
   2  * linux/drivers/cpufreq/proc_intf.c
   3  *
   4  * Copyright (C) 2002 - 2003 Dominik Brodowski
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/cpufreq.h>
  11 #include <linux/ctype.h>
  12 #include <linux/proc_fs.h>
  13 #include <asm/uaccess.h>
  14
  15 #warning This module will be removed from the 2.6. kernel series soon after 2005-01-01
  16
  17 #define CPUFREQ_ALL_CPUS                ((NR_CPUS))
  18
  19 static unsigned int warning_print = 0;
  20
  21 /**
  22  * cpufreq_parse_policy - parse a policy string
  23  * @input_string: the string to parse.
  24  * @policy: the policy written inside input_string
  25  *
  26  * This function parses a "policy string" - something the user echo'es into
  27  * /proc/cpufreq or gives as boot parameter - into a struct cpufreq_policy.
  28  * If there are invalid/missing entries, they are replaced with current
  29  * cpufreq policy.
  30  */
  31 static int cpufreq_parse_policy(char input_string[42], struct cpufreq_policy *policy)
  32 {
  33         unsigned int            min = 0;
  34         unsigned int            max = 0;
  35         unsigned int            cpu = 0;
  36         char                    str_governor[16];
  37         struct cpufreq_policy   current_policy;
  38         unsigned int            result = -EFAULT;
  39
  40         if (!policy)
  41                 return -EINVAL;
  42
  43         policy->min = 0;
  44         policy->max = 0;
  45         policy->policy = 0;
  46         policy->cpu = CPUFREQ_ALL_CPUS;
  47
  48         if (sscanf(input_string, "%d:%d:%d:%15s", &cpu, &min, &max, str_governor) == 4)
  49         {
  50                 policy->min = min;
  51                 policy->max = max;
  52                 policy->cpu = cpu;
  53                 result = 0;
  54                 goto scan_policy;
  55         }
  56         if (sscanf(input_string, "%d%%%d%%%d%%%15s", &cpu, &min, &max, str_governor) == 4)
  57         {
  58                 if (!cpufreq_get_policy(&current_policy, cpu)) {
  59                         policy->min = (min * current_policy.cpuinfo.max_freq) / 100;
  60                         policy->max = (max * current_policy.cpuinfo.max_freq) / 100;
  61                         policy->cpu = cpu;
  62                         result = 0;
  63                         goto scan_policy;
  64                 }
  65         }
  66
  67         if (sscanf(input_string, "%d:%d:%15s", &min, &max, str_governor) == 3)
  68         {
  69                 policy->min = min;
  70                 policy->max = max;
  71                 result = 0;
  72                 goto scan_policy;
  73         }
  74
  75         if (sscanf(input_string, "%d%%%d%%%15s", &min, &max, str_governor) == 3)
  76         {
  77                 if (!cpufreq_get_policy(&current_policy, cpu)) {
  78                         policy->min = (min * current_policy.cpuinfo.max_freq) / 100;
  79                         policy->max = (max * current_policy.cpuinfo.max_freq) / 100;
  80                         result = 0;
  81                         goto scan_policy;
  82                 }
  83         }
  84
  85         return -EINVAL;
  86
  87 scan_policy:
  88         result = cpufreq_parse_governor(str_governor, &policy->policy, &policy->governor);
  89
  90         return result;
  91 }
  92
  93 /**
  94  * cpufreq_proc_read - read /proc/cpufreq
  95  *
  96  * This function prints out the current cpufreq policy.
  97  */
  98 static int cpufreq_proc_read (
  99         char                    *page,
 100         char                    **start,
 101         off_t                   off,
 102         int                     count,
 103         int                     *eof,
 104         void                    *data)
 105 {
 106         char                    *p = page;
 107         int                     len = 0;
 108         struct cpufreq_policy   policy;
 109         unsigned int            min_pctg = 0;
 110         unsigned int            max_pctg = 0;
 111         unsigned int            i = 0;
 112
 113         if (off != 0)
 114                 goto end;
 115
 116         if (!warning_print) {
 117                 warning_print++;
 118                 printk(KERN_INFO "Access to /proc/cpufreq is deprecated and "
 119                         "will be removed from (new) 2.6. kernels soon "
 120                         "after 2005-01-01\n");
 121         }
 122
 123         p += sprintf(p, "          minimum CPU frequency  -  maximum CPU frequency  -  policy\n");
 124         for (i=0;i<NR_CPUS;i++) {
 125                 if (!cpu_online(i))
 126                         continue;
 127
 128                 if (cpufreq_get_policy(&policy, i))
 129                         continue;
 130
 131                 if (!policy.cpuinfo.max_freq)
 132                         continue;
 133
 134                 min_pctg = (policy.min * 100) / policy.cpuinfo.max_freq;
 135                 max_pctg = (policy.max * 100) / policy.cpuinfo.max_freq;
 136
 137                 p += sprintf(p, "CPU%3d    %9d kHz (%3d %%)  -  %9d kHz (%3d %%)  -  ",
 138                              i , policy.min, min_pctg, policy.max, max_pctg);
 139                 if (policy.policy) {
 140                         switch (policy.policy) {
 141                                 case CPUFREQ_POLICY_POWERSAVE:
 142                                 p += sprintf(p, "powersave\n");
 143                                 break;
 144                         case CPUFREQ_POLICY_PERFORMANCE:
 145                                 p += sprintf(p, "performance\n");
 146                                 break;
 147                         default:
 148                                 p += sprintf(p, "INVALID\n");
 149                                 break;
 150                         }
 151                 } else
 152                         p += scnprintf(p, CPUFREQ_NAME_LEN, "%s\n", policy.governor->name);
 153         }
 154 end:
 155         len = (p - page);
 156         if (len <= off+count)
 157                 *eof = 1;
 158         *start = page + off;
 159         len -= off;
 160         if (len>count)
 161                 len = count;
 162         if (len<0)
 163                 len = 0;
 164
 165         return len;
 166 }
 167
 168
 169 /**
 170  * cpufreq_proc_write - handles writing into /proc/cpufreq
 171  *
 172  * This function calls the parsing script and then sets the policy
 173  * accordingly.
 174  */
 175 static int cpufreq_proc_write (
 176         struct file             *file,
 177         const char              __user *buffer,
 178         unsigned long           count,
 179         void                    *data)
 180 {
 181         int                     result = 0;
 182         char                    proc_string[42] = {'\0'};
 183         struct cpufreq_policy   policy;
 184         unsigned int            i = 0;
 185
 186
 187         if ((count > sizeof(proc_string) - 1))
 188                 return -EINVAL;
 189
 190         if (copy_from_user(proc_string, buffer, count))
 191                 return -EFAULT;
 192
 193         if (!warning_print) {
 194                 warning_print++;
 195                 printk(KERN_INFO "Access to /proc/cpufreq is deprecated and "
 196                         "will be removed from (new) 2.6. kernels soon "
 197                         "after 2005-01-01\n");
 198         }
 199
 200         proc_string[count] = '\0';
 201
 202         result = cpufreq_parse_policy(proc_string, &policy);
 203         if (result)
 204                 return -EFAULT;
 205
 206         if (policy.cpu == CPUFREQ_ALL_CPUS)
 207         {
 208                 for (i=0; i<NR_CPUS; i++)
 209                 {
 210                         policy.cpu = i;
 211                         if (cpu_online(i))
 212                                 cpufreq_set_policy(&policy);
 213                 }
 214         }
 215         else
 216                 cpufreq_set_policy(&policy);
 217
 218         return count;
 219 }
 220
 221
 222 /**
 223  * cpufreq_proc_init - add "cpufreq" to the /proc root directory
 224  *
 225  * This function adds "cpufreq" to the /proc root directory.
 226  */
 227 static int __init cpufreq_proc_init (void)
 228 {
 229         struct proc_dir_entry *entry = NULL;
 230
 231         /* are these acceptable values? */
 232         entry = create_proc_entry("cpufreq", S_IFREG|S_IRUGO|S_IWUSR,
 233                                   &proc_root);
 234
 235         if (!entry) {
 236                 printk(KERN_ERR "unable to create /proc/cpufreq entry\n");
 237                 return -EIO;
 238         } else {
 239                 entry->read_proc = cpufreq_proc_read;
 240                 entry->write_proc = cpufreq_proc_write;
 241         }
 242
 243         return 0;
 244 }
 245
 246
 247 /**
 248  * cpufreq_proc_exit - removes "cpufreq" from the /proc root directory.
 249  *
 250  * This function removes "cpufreq" from the /proc root directory.
 251  */
 252 static void __exit cpufreq_proc_exit (void)
 253 {
 254         remove_proc_entry("cpufreq", &proc_root);
 255         return;
 256 }
 257
 258 MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>");
 259 MODULE_DESCRIPTION ("CPUfreq /proc/cpufreq interface");
 260 MODULE_LICENSE ("GPL");
 261
 262 module_init(cpufreq_proc_init);
 263 module_exit(cpufreq_proc_exit);