arch/powerpc/platforms/pseries/pseries_energy.c

   1 /*
   2  * POWER platform energy management driver
   3  * Copyright (C) 2010 IBM Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * version 2 as published by the Free Software Foundation.
   8  *
   9  * This pseries platform device driver provides access to
  10  * platform energy management capabilities.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/init.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/device.h>
  19 #include <linux/cpu.h>
  20 #include <linux/of.h>
  21 #include <asm/cputhreads.h>
  22 #include <asm/page.h>
  23 #include <asm/hvcall.h>
  24 #include <asm/firmware.h>
  25 #include <asm/prom.h>
  26
  27
  28 #define MODULE_VERS "1.0"
  29 #define MODULE_NAME "pseries_energy"
  30
  31 /* Driver flags */
  32
  33 static int sysfs_entries;
  34
  35 /* Helper routines */
  36
  37 /* Helper Routines to convert between drc_index to cpu numbers */
  38
  39 static u32 cpu_to_drc_index(int cpu)
  40 {
  41         struct device_node *dn = NULL;
  42         int thread_index;
  43         int rc = 1;
  44         u32 ret = 0;
  45
  46         dn = of_find_node_by_path("/cpus");
  47         if (dn == NULL)
  48                 goto err;
  49
  50         /* Convert logical cpu number to core number */
  51         thread_index = cpu_core_index_of_thread(cpu);
  52
  53         if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
  54                 struct property *info = NULL;
  55                 struct of_drc_info drc;
  56                 int j;
  57                 u32 num_set_entries;
  58                 const __be32 *value;
  59
  60                 info = of_find_property(dn, "ibm,drc-info", NULL);
  61                 if (info == NULL)
  62                         goto err_of_node_put;
  63
  64                 value = of_prop_next_u32(info, NULL, &num_set_entries);
  65                 if (!value)
  66                         goto err_of_node_put;
  67
  68                 for (j = 0; j < num_set_entries; j++) {
  69
  70                         of_read_drc_info_cell(&info, &value, &drc);
  71                         if (strncmp(drc.drc_type, "CPU", 3))
  72                                 goto err;
  73
  74                         if (thread_index < drc.last_drc_index)
  75                                 break;
  76                 }
  77
  78                 ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
  79         } else {
  80                 const __be32 *indexes;
  81
  82                 indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
  83                 if (indexes == NULL)
  84                         goto err_of_node_put;
  85
  86                 /*
  87                  * The first element indexes[0] is the number of drc_indexes
  88                  * returned in the list.  Hence thread_index+1 will get the
  89                  * drc_index corresponding to core number thread_index.
  90                  */
  91                 ret = indexes[thread_index + 1];
  92         }
  93
  94         rc = 0;
  95
  96 err_of_node_put:
  97         of_node_put(dn);
  98 err:
  99         if (rc)
 100                 printk(KERN_WARNING "cpu_to_drc_index(%d) failed", cpu);
 101         return ret;
 102 }
 103
 104 static int drc_index_to_cpu(u32 drc_index)
 105 {
 106         struct device_node *dn = NULL;
 107         const int *indexes;
 108         int thread_index = 0, cpu = 0;
 109         int rc = 1;
 110
 111         dn = of_find_node_by_path("/cpus");
 112         if (dn == NULL)
 113                 goto err;
 114
 115         if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
 116                 struct property *info = NULL;
 117                 struct of_drc_info drc;
 118                 int j;
 119                 u32 num_set_entries;
 120                 const __be32 *value;
 121
 122                 info = of_find_property(dn, "ibm,drc-info", NULL);
 123                 if (info == NULL)
 124                         goto err_of_node_put;
 125
 126                 value = of_prop_next_u32(info, NULL, &num_set_entries);
 127                 if (!value)
 128                         goto err_of_node_put;
 129
 130                 for (j = 0; j < num_set_entries; j++) {
 131
 132                         of_read_drc_info_cell(&info, &value, &drc);
 133                         if (strncmp(drc.drc_type, "CPU", 3))
 134                                 goto err;
 135
 136                         if (drc_index > drc.last_drc_index) {
 137                                 cpu += drc.num_sequential_elems;
 138                                 continue;
 139                         }
 140                         cpu += ((drc_index - drc.drc_index_start) /
 141                                 drc.sequential_inc);
 142
 143                         thread_index = cpu_first_thread_of_core(cpu);
 144                         rc = 0;
 145                         break;
 146                 }
 147         } else {
 148                 unsigned long int i;
 149
 150                 indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
 151                 if (indexes == NULL)
 152                         goto err_of_node_put;
 153                 /*
 154                  * First element in the array is the number of drc_indexes
 155                  * returned.  Search through the list to find the matching
 156                  * drc_index and get the core number
 157                  */
 158                 for (i = 0; i < indexes[0]; i++) {
 159                         if (indexes[i + 1] == drc_index)
 160                                 break;
 161                 }
 162                 /* Convert core number to logical cpu number */
 163                 thread_index = cpu_first_thread_of_core(i);
 164                 rc = 0;
 165         }
 166
 167 err_of_node_put:
 168         of_node_put(dn);
 169 err:
 170         if (rc)
 171                 printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
 172         return thread_index;
 173 }
 174
 175 /*
 176  * pseries hypervisor call H_BEST_ENERGY provides hints to OS on
 177  * preferred logical cpus to activate or deactivate for optimized
 178  * energy consumption.
 179  */
 180
 181 #define FLAGS_MODE1     0x004E200000080E01UL
 182 #define FLAGS_MODE2     0x004E200000080401UL
 183 #define FLAGS_ACTIVATE  0x100
 184
 185 static ssize_t get_best_energy_list(char *page, int activate)
 186 {
 187         int rc, cnt, i, cpu;
 188         unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
 189         unsigned long flags = 0;
 190         u32 *buf_page;
 191         char *s = page;
 192
 193         buf_page = (u32 *) get_zeroed_page(GFP_KERNEL);
 194         if (!buf_page)
 195                 return -ENOMEM;
 196
 197         flags = FLAGS_MODE1;
 198         if (activate)
 199                 flags |= FLAGS_ACTIVATE;
 200
 201         rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags, 0, __pa(buf_page),
 202                                 0, 0, 0, 0, 0, 0);
 203         if (rc != H_SUCCESS) {
 204                 free_page((unsigned long) buf_page);
 205                 return -EINVAL;
 206         }
 207
 208         cnt = retbuf[0];
 209         for (i = 0; i < cnt; i++) {
 210                 cpu = drc_index_to_cpu(buf_page[2*i+1]);
 211                 if ((cpu_online(cpu) && !activate) ||
 212                     (!cpu_online(cpu) && activate))
 213                         s += sprintf(s, "%d,", cpu);
 214         }
 215         if (s > page) { /* Something to show */
 216                 s--; /* Suppress last comma */
 217                 s += sprintf(s, "\n");
 218         }
 219
 220         free_page((unsigned long) buf_page);
 221         return s-page;
 222 }
 223
 224 static ssize_t get_best_energy_data(struct device *dev,
 225                                         char *page, int activate)
 226 {
 227         int rc;
 228         unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
 229         unsigned long flags = 0;
 230
 231         flags = FLAGS_MODE2;
 232         if (activate)
 233                 flags |= FLAGS_ACTIVATE;
 234
 235         rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags,
 236                                 cpu_to_drc_index(dev->id),
 237                                 0, 0, 0, 0, 0, 0, 0);
 238
 239         if (rc != H_SUCCESS)
 240                 return -EINVAL;
 241
 242         return sprintf(page, "%lu\n", retbuf[1] >> 32);
 243 }
 244
 245 /* Wrapper functions */
 246
 247 static ssize_t cpu_activate_hint_list_show(struct device *dev,
 248                         struct device_attribute *attr, char *page)
 249 {
 250         return get_best_energy_list(page, 1);
 251 }
 252
 253 static ssize_t cpu_deactivate_hint_list_show(struct device *dev,
 254                         struct device_attribute *attr, char *page)
 255 {
 256         return get_best_energy_list(page, 0);
 257 }
 258
 259 static ssize_t percpu_activate_hint_show(struct device *dev,
 260                         struct device_attribute *attr, char *page)
 261 {
 262         return get_best_energy_data(dev, page, 1);
 263 }
 264
 265 static ssize_t percpu_deactivate_hint_show(struct device *dev,
 266                         struct device_attribute *attr, char *page)
 267 {
 268         return get_best_energy_data(dev, page, 0);
 269 }
 270
 271 /*
 272  * Create sysfs interface:
 273  * /sys/devices/system/cpu/pseries_activate_hint_list
 274  * /sys/devices/system/cpu/pseries_deactivate_hint_list
 275  *      Comma separated list of cpus to activate or deactivate
 276  * /sys/devices/system/cpu/cpuN/pseries_activate_hint
 277  * /sys/devices/system/cpu/cpuN/pseries_deactivate_hint
 278  *      Per-cpu value of the hint
 279  */
 280
 281 static struct device_attribute attr_cpu_activate_hint_list =
 282                 __ATTR(pseries_activate_hint_list, 0444,
 283                 cpu_activate_hint_list_show, NULL);
 284
 285 static struct device_attribute attr_cpu_deactivate_hint_list =
 286                 __ATTR(pseries_deactivate_hint_list, 0444,
 287                 cpu_deactivate_hint_list_show, NULL);
 288
 289 static struct device_attribute attr_percpu_activate_hint =
 290                 __ATTR(pseries_activate_hint, 0444,
 291                 percpu_activate_hint_show, NULL);
 292
 293 static struct device_attribute attr_percpu_deactivate_hint =
 294                 __ATTR(pseries_deactivate_hint, 0444,
 295                 percpu_deactivate_hint_show, NULL);
 296
 297 static int __init pseries_energy_init(void)
 298 {
 299         int cpu, err;
 300         struct device *cpu_dev;
 301
 302         if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
 303                 return 0; /* H_BEST_ENERGY hcall not supported */
 304
 305         /* Create the sysfs files */
 306         err = device_create_file(cpu_subsys.dev_root,
 307                                 &attr_cpu_activate_hint_list);
 308         if (!err)
 309                 err = device_create_file(cpu_subsys.dev_root,
 310                                 &attr_cpu_deactivate_hint_list);
 311
 312         if (err)
 313                 return err;
 314         for_each_possible_cpu(cpu) {
 315                 cpu_dev = get_cpu_device(cpu);
 316                 err = device_create_file(cpu_dev,
 317                                 &attr_percpu_activate_hint);
 318                 if (err)
 319                         break;
 320                 err = device_create_file(cpu_dev,
 321                                 &attr_percpu_deactivate_hint);
 322                 if (err)
 323                         break;
 324         }
 325
 326         if (err)
 327                 return err;
 328
 329         sysfs_entries = 1; /* Removed entries on cleanup */
 330         return 0;
 331
 332 }
 333
 334 static void __exit pseries_energy_cleanup(void)
 335 {
 336         int cpu;
 337         struct device *cpu_dev;
 338
 339         if (!sysfs_entries)
 340                 return;
 341
 342         /* Remove the sysfs files */
 343         device_remove_file(cpu_subsys.dev_root, &attr_cpu_activate_hint_list);
 344         device_remove_file(cpu_subsys.dev_root, &attr_cpu_deactivate_hint_list);
 345
 346         for_each_possible_cpu(cpu) {
 347                 cpu_dev = get_cpu_device(cpu);
 348                 sysfs_remove_file(&cpu_dev->kobj,
 349                                 &attr_percpu_activate_hint.attr);
 350                 sysfs_remove_file(&cpu_dev->kobj,
 351                                 &attr_percpu_deactivate_hint.attr);
 352         }
 353 }
 354
 355 module_init(pseries_energy_init);
 356 module_exit(pseries_energy_cleanup);
 357 MODULE_DESCRIPTION("Driver for pSeries platform energy management");
 358 MODULE_AUTHOR("Vaidyanathan Srinivasan");
 359 MODULE_LICENSE("GPL");