drivers/acpi/cpu.c

   1 /*
   2  *  cpu.c - Processor handling
   3  *
   4  *  Copyright (C) 2000 Andrew Henroid
   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 as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/kernel.h>
  23 #include <linux/pm.h>
  24 #include <linux/acpi.h>
  25 #include "acpi.h"
  26 #include "driver.h"
  27
  28 #define _COMPONENT      OS_DEPENDENT
  29         MODULE_NAME     ("cpu")
  30
  31 unsigned long acpi_c2_exit_latency = ACPI_INFINITE;
  32 unsigned long acpi_c3_exit_latency = ACPI_INFINITE;
  33 unsigned long acpi_c2_enter_latency = ACPI_INFINITE;
  34 unsigned long acpi_c3_enter_latency = ACPI_INFINITE;
  35
  36 static unsigned long acpi_pblk = ACPI_INVALID;
  37 static int acpi_c2_tested = 0;
  38 static int acpi_c3_tested = 0;
  39 static int acpi_max_c_state = 1;
  40 static int acpi_pm_tmr_len;
  41
  42 /*
  43  * Clear busmaster activity flag
  44  */
  45 static inline void
  46 acpi_clear_bm_activity(void)
  47 {
  48         acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_LOCK, BM_STS, 0);
  49 }
  50
  51 /*
  52  * Returns 1 if there has been busmaster activity
  53  */
  54 static inline int
  55 acpi_bm_activity(void)
  56 {
  57         return acpi_hw_register_bit_access(ACPI_READ, ACPI_MTX_LOCK, BM_STS);
  58 }
  59
  60 /*
  61  * Set system to sleep through busmaster requests
  62  */
  63 static void
  64 acpi_sleep_on_busmaster(void)
  65 {
  66         acpi_hw_register_bit_access (ACPI_WRITE, ACPI_MTX_LOCK, BM_RLD, 1);
  67 }
  68
  69 /*
  70  * Set system to wake on busmaster requests
  71  */
  72 static void
  73 acpi_wake_on_busmaster(void)
  74 {
  75         acpi_hw_register_bit_access (ACPI_WRITE, ACPI_MTX_LOCK, BM_RLD, 0);
  76 }
  77
  78 u32
  79 acpi_read_pm_timer(void)
  80 {
  81         return acpi_hw_register_read(ACPI_MTX_LOCK, PM_TIMER);
  82 }
  83
  84 /*
  85  * Do a compare, accounting for 24/32bit rollover
  86  */
  87 static u32
  88 acpi_compare_pm_timers(u32 first, u32 second)
  89 {
  90         if (first < second) {
  91                 return (second - first);
  92         } else {
  93                 if (acpi_pm_tmr_len == 24)
  94                         return (second + (0xFFFFFF - first));
  95                 else
  96                         return (second + (0xFFFFFFFF - first));
  97         }
  98 }
  99
 100 /*
 101  * Idle loop (uniprocessor only)
 102  */
 103 static void
 104 acpi_idle(void)
 105 {
 106         static int sleep_level = 1;
 107         FADT_DESCRIPTOR *fadt = &acpi_fadt;
 108
 109         if (!fadt
 110             || (STRNCMP(fadt->header.signature, ACPI_FADT_SIGNATURE, ACPI_SIG_LEN) != 0)
 111             || !fadt->Xpm_tmr_blk.address
 112             || !acpi_pblk)
 113                 goto not_initialized;
 114
 115         /*
 116          * start from the previous sleep level..
 117          */
 118         if (sleep_level == 1
 119             || acpi_max_c_state < 2)
 120                 goto sleep1;
 121
 122         if (sleep_level == 2
 123             || acpi_max_c_state < 3)
 124                 goto sleep2;
 125
 126       sleep3:
 127         sleep_level = 3;
 128         if (!acpi_c3_tested) {
 129                 DEBUG_PRINT(ACPI_INFO, ("C3 works\n"));
 130                 acpi_c3_tested = 1;
 131         }
 132         acpi_wake_on_busmaster();
 133         if (fadt->Xpm2_cnt_blk.address)
 134                 goto sleep3_with_arbiter;
 135
 136         for (;;) {
 137                 unsigned long time;
 138                 unsigned long diff;
 139
 140                 __cli();
 141                 if (current->need_resched)
 142                         goto out;
 143                 if (acpi_bm_activity())
 144                         goto sleep2;
 145
 146                 time = acpi_read_pm_timer();
 147                 inb(acpi_pblk + ACPI_P_LVL3);
 148                 /* Dummy read, force synchronization with the PMU */
 149                 acpi_read_pm_timer();
 150                 diff = acpi_compare_pm_timers(time, acpi_read_pm_timer());
 151
 152                 __sti();
 153                 if (diff < acpi_c3_exit_latency)
 154                         goto sleep2;
 155         }
 156
 157       sleep3_with_arbiter:
 158         for (;;) {
 159                 unsigned long time;
 160                 unsigned long diff;
 161
 162                 __cli();
 163                 if (current->need_resched)
 164                         goto out;
 165                 if (acpi_bm_activity())
 166                         goto sleep2;
 167
 168                 time = acpi_read_pm_timer();
 169
 170                 /* Disable arbiter, park on CPU */
 171                 acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_LOCK, ARB_DIS, 1);
 172                 inb(acpi_pblk + ACPI_P_LVL3);
 173                 /* Dummy read, force synchronization with the PMU */
 174                 acpi_read_pm_timer();
 175                 diff = acpi_compare_pm_timers(time, acpi_read_pm_timer());
 176                 /* Enable arbiter again.. */
 177                 acpi_hw_register_bit_access(ACPI_WRITE, ACPI_MTX_LOCK, ARB_DIS, 0);
 178
 179                 __sti();
 180                 if (diff < acpi_c3_exit_latency)
 181                         goto sleep2;
 182         }
 183
 184       sleep2:
 185         sleep_level = 2;
 186         if (!acpi_c2_tested) {
 187                 DEBUG_PRINT(ACPI_INFO, ("C2 works\n"));
 188                 acpi_c2_tested = 1;
 189         }
 190         acpi_wake_on_busmaster();       /* Required to track BM activity.. */
 191         for (;;) {
 192                 unsigned long time;
 193                 unsigned long diff;
 194
 195                 __cli();
 196                 if (current->need_resched)
 197                         goto out;
 198
 199                 time = acpi_read_pm_timer();
 200                 inb(acpi_pblk + ACPI_P_LVL2);
 201                 /* Dummy read, force synchronization with the PMU */
 202                 acpi_read_pm_timer();
 203                 diff = acpi_compare_pm_timers(time, acpi_read_pm_timer());
 204
 205                 __sti();
 206                 if (diff < acpi_c2_exit_latency)
 207                         goto sleep1;
 208                 if (acpi_bm_activity()) {
 209                         acpi_clear_bm_activity();
 210                         continue;
 211                 }
 212                 if (diff > acpi_c3_enter_latency
 213                     && acpi_max_c_state >= 3)
 214                         goto sleep3;
 215         }
 216
 217       sleep1:
 218         sleep_level = 1;
 219         acpi_sleep_on_busmaster();
 220         for (;;) {
 221                 unsigned long time;
 222                 unsigned long diff;
 223
 224                 __cli();
 225                 if (current->need_resched)
 226                         goto out;
 227                 time = acpi_read_pm_timer();
 228                 safe_halt();
 229                 diff = acpi_compare_pm_timers(time, acpi_read_pm_timer());
 230                 if (diff > acpi_c2_enter_latency
 231                     && acpi_max_c_state >= 2)
 232                         goto sleep2;
 233         }
 234
 235       not_initialized:
 236         for (;;) {
 237                 __cli();
 238                 if (current->need_resched)
 239                         goto out;
 240                 safe_halt();
 241         }
 242
 243       out:
 244         __sti();
 245 }
 246
 247 /*
 248  * Get processor information
 249  */
 250 static ACPI_STATUS
 251 acpi_found_cpu(ACPI_HANDLE handle, u32 level, void *ctx, void **value)
 252 {
 253         ACPI_OBJECT obj;
 254         ACPI_CX_STATE lat[4];
 255         ACPI_CPU_THROTTLING_STATE throttle[ACPI_MAX_THROTTLE];
 256         ACPI_BUFFER buf;
 257         int i, count;
 258
 259         buf.length = sizeof(obj);
 260         buf.pointer = &obj;
 261         if (!ACPI_SUCCESS(acpi_evaluate_object(handle, NULL, NULL, &buf)))
 262                 return AE_OK;
 263
 264         DEBUG_PRINT(ACPI_INFO, ("PBLK %d @ 0x%04x:%d\n",
 265                         obj.processor.proc_id,
 266                         obj.processor.pblk_address,
 267                         obj.processor.pblk_length));
 268
 269         if (acpi_pblk != ACPI_INVALID
 270             || !obj.processor.pblk_address
 271             || obj.processor.pblk_length != 6)
 272                 return AE_OK;
 273
 274         acpi_pblk = obj.processor.pblk_address;
 275
 276         buf.length = sizeof(lat);
 277         buf.pointer = lat;
 278         if (!ACPI_SUCCESS(acpi_get_processor_cx_info(handle, &buf)))
 279                 return AE_OK;
 280
 281         if (lat[2].latency < MAX_CX_STATE_LATENCY) {
 282                 printk(KERN_INFO "ACPI: System firmware supports: C2");
 283                 acpi_c2_exit_latency = lat[2].latency;
 284                 acpi_max_c_state = 2;
 285
 286                 if (lat[3].latency < MAX_CX_STATE_LATENCY) {
 287                         printk(" C3");
 288                         acpi_c3_exit_latency = lat[3].latency;
 289                         acpi_max_c_state = 3;
 290                 }
 291                 printk("\n");
 292         }
 293
 294         memset(throttle, 0, sizeof(throttle));
 295         buf.length = sizeof(throttle);
 296         buf.pointer = throttle;
 297
 298         if (!ACPI_SUCCESS(acpi_get_processor_throttling_info(handle, &buf)))
 299                 return AE_OK;
 300
 301         for (i = 0, count = 0; i < ACPI_MAX_THROTTLE; i++) {
 302                 if (throttle[i].percent_of_clock)
 303                         count++;
 304         }
 305
 306         /* 0% throttled really doesn't count */
 307         count--;
 308
 309         if (count > 0) {
 310                 DEBUG_PRINT(ACPI_INFO, ("%d throttling states\n", count));
 311         }
 312
 313         return AE_OK;
 314 }
 315
 316 static int
 317 acpi_pm_timer_init(void)
 318 {
 319         FADT_DESCRIPTOR *fadt = &acpi_fadt;
 320
 321         if (fadt->tmr_val_ext) {
 322                 acpi_pm_tmr_len = 32;
 323         } else {
 324                 acpi_pm_tmr_len = 24;
 325         }
 326
 327         DEBUG_PRINT(ACPI_INFO, ("PM Timer width: %d bits\n", acpi_pm_tmr_len));
 328
 329         return AE_OK;
 330 }
 331
 332 int
 333 acpi_cpu_init(void)
 334 {
 335         acpi_walk_namespace(ACPI_TYPE_PROCESSOR,
 336                             ACPI_ROOT_OBJECT,
 337                             ACPI_UINT32_MAX,
 338                             acpi_found_cpu,
 339                             NULL,
 340                             NULL);
 341
 342         acpi_pm_timer_init();
 343
 344
 345 #ifdef CONFIG_SMP
 346         if (smp_num_cpus == 1)
 347                 pm_idle = acpi_idle;
 348 #else
 349         pm_idle = acpi_idle;
 350 #endif
 351
 352         return 0;
 353 }