1 /* 2 * cpuidle-powernv - idle state cpuidle driver. 3 * Adapted from drivers/cpuidle/cpuidle-pseries 4 * 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/moduleparam.h> 11 #include <linux/cpuidle.h> 12 #include <linux/cpu.h> 13 #include <linux/notifier.h> 14 #include <linux/clockchips.h> 15 #include <linux/of.h> 16 #include <linux/slab.h> 17 18 #include <asm/machdep.h> 19 #include <asm/firmware.h> 20 #include <asm/opal.h> 21 #include <asm/runlatch.h> 22 #include <asm/cpuidle.h> 23 24 /* 25 * Expose only those Hardware idle states via the cpuidle framework 26 * that have latency value below POWERNV_THRESHOLD_LATENCY_NS. 27 */ 28 #define POWERNV_THRESHOLD_LATENCY_NS 200000 29 30 static struct cpuidle_driver powernv_idle_driver = { 31 .name = "powernv_idle", 32 .owner = THIS_MODULE, 33 }; 34 35 static int max_idle_state; 36 static struct cpuidle_state *cpuidle_state_table; 37 38 struct stop_psscr_table { 39 u64 val; 40 u64 mask; 41 }; 42 43 static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX]; 44 45 static u64 snooze_timeout; 46 static bool snooze_timeout_en; 47 48 static int snooze_loop(struct cpuidle_device *dev, 49 struct cpuidle_driver *drv, 50 int index) 51 { 52 u64 snooze_exit_time; 53 54 local_irq_enable(); 55 set_thread_flag(TIF_POLLING_NRFLAG); 56 57 snooze_exit_time = get_tb() + snooze_timeout; 58 ppc64_runlatch_off(); 59 HMT_very_low(); 60 while (!need_resched()) { 61 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) 62 break; 63 } 64 65 HMT_medium(); 66 ppc64_runlatch_on(); 67 clear_thread_flag(TIF_POLLING_NRFLAG); 68 smp_mb(); 69 return index; 70 } 71 72 static int nap_loop(struct cpuidle_device *dev, 73 struct cpuidle_driver *drv, 74 int index) 75 { 76 ppc64_runlatch_off(); 77 power7_idle(); 78 ppc64_runlatch_on(); 79 return index; 80 } 81 82 /* Register for fastsleep only in oneshot mode of broadcast */ 83 #ifdef CONFIG_TICK_ONESHOT 84 static int fastsleep_loop(struct cpuidle_device *dev, 85 struct cpuidle_driver *drv, 86 int index) 87 { 88 unsigned long old_lpcr = mfspr(SPRN_LPCR); 89 unsigned long new_lpcr; 90 91 if (unlikely(system_state < SYSTEM_RUNNING)) 92 return index; 93 94 new_lpcr = old_lpcr; 95 /* Do not exit powersave upon decrementer as we've setup the timer 96 * offload. 97 */ 98 new_lpcr &= ~LPCR_PECE1; 99 100 mtspr(SPRN_LPCR, new_lpcr); 101 power7_sleep(); 102 103 mtspr(SPRN_LPCR, old_lpcr); 104 105 return index; 106 } 107 #endif 108 109 static int stop_loop(struct cpuidle_device *dev, 110 struct cpuidle_driver *drv, 111 int index) 112 { 113 ppc64_runlatch_off(); 114 power9_idle_stop(stop_psscr_table[index].val, 115 stop_psscr_table[index].mask); 116 ppc64_runlatch_on(); 117 return index; 118 } 119 120 /* 121 * States for dedicated partition case. 122 */ 123 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = { 124 { /* Snooze */ 125 .name = "snooze", 126 .desc = "snooze", 127 .exit_latency = 0, 128 .target_residency = 0, 129 .enter = snooze_loop }, 130 }; 131 132 static int powernv_cpuidle_cpu_online(unsigned int cpu) 133 { 134 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 135 136 if (dev && cpuidle_get_driver()) { 137 cpuidle_pause_and_lock(); 138 cpuidle_enable_device(dev); 139 cpuidle_resume_and_unlock(); 140 } 141 return 0; 142 } 143 144 static int powernv_cpuidle_cpu_dead(unsigned int cpu) 145 { 146 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 147 148 if (dev && cpuidle_get_driver()) { 149 cpuidle_pause_and_lock(); 150 cpuidle_disable_device(dev); 151 cpuidle_resume_and_unlock(); 152 } 153 return 0; 154 } 155 156 /* 157 * powernv_cpuidle_driver_init() 158 */ 159 static int powernv_cpuidle_driver_init(void) 160 { 161 int idle_state; 162 struct cpuidle_driver *drv = &powernv_idle_driver; 163 164 drv->state_count = 0; 165 166 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { 167 /* Is the state not enabled? */ 168 if (cpuidle_state_table[idle_state].enter == NULL) 169 continue; 170 171 drv->states[drv->state_count] = /* structure copy */ 172 cpuidle_state_table[idle_state]; 173 174 drv->state_count += 1; 175 } 176 177 /* 178 * On the PowerNV platform cpu_present may be less than cpu_possible in 179 * cases when firmware detects the CPU, but it is not available to the 180 * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at 181 * run time and hence cpu_devices are not created for those CPUs by the 182 * generic topology_init(). 183 * 184 * drv->cpumask defaults to cpu_possible_mask in 185 * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where 186 * cpu_devices are not created for CPUs in cpu_possible_mask that 187 * cannot be hot-added later at run time. 188 * 189 * Trying cpuidle_register_device() on a CPU without a cpu_device is 190 * incorrect, so pass a correct CPU mask to the generic cpuidle driver. 191 */ 192 193 drv->cpumask = (struct cpumask *)cpu_present_mask; 194 195 return 0; 196 } 197 198 static inline void add_powernv_state(int index, const char *name, 199 unsigned int flags, 200 int (*idle_fn)(struct cpuidle_device *, 201 struct cpuidle_driver *, 202 int), 203 unsigned int target_residency, 204 unsigned int exit_latency, 205 u64 psscr_val, u64 psscr_mask) 206 { 207 strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); 208 strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); 209 powernv_states[index].flags = flags; 210 powernv_states[index].target_residency = target_residency; 211 powernv_states[index].exit_latency = exit_latency; 212 powernv_states[index].enter = idle_fn; 213 stop_psscr_table[index].val = psscr_val; 214 stop_psscr_table[index].mask = psscr_mask; 215 } 216 217 /* 218 * Returns 0 if prop1_len == prop2_len. Else returns -1 219 */ 220 static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len, 221 const char *prop2, int prop2_len) 222 { 223 if (prop1_len == prop2_len) 224 return 0; 225 226 pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n", 227 prop1, prop2); 228 return -1; 229 } 230 231 static int powernv_add_idle_states(void) 232 { 233 struct device_node *power_mgt; 234 int nr_idle_states = 1; /* Snooze */ 235 int dt_idle_states, count; 236 u32 latency_ns[CPUIDLE_STATE_MAX]; 237 u32 residency_ns[CPUIDLE_STATE_MAX]; 238 u32 flags[CPUIDLE_STATE_MAX]; 239 u64 psscr_val[CPUIDLE_STATE_MAX]; 240 u64 psscr_mask[CPUIDLE_STATE_MAX]; 241 const char *names[CPUIDLE_STATE_MAX]; 242 u32 has_stop_states = 0; 243 int i, rc; 244 245 /* Currently we have snooze statically defined */ 246 247 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); 248 if (!power_mgt) { 249 pr_warn("opal: PowerMgmt Node not found\n"); 250 goto out; 251 } 252 253 /* Read values of any property to determine the num of idle states */ 254 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags"); 255 if (dt_idle_states < 0) { 256 pr_warn("cpuidle-powernv: no idle states found in the DT\n"); 257 goto out; 258 } 259 260 count = of_property_count_u32_elems(power_mgt, 261 "ibm,cpu-idle-state-latencies-ns"); 262 263 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states, 264 "ibm,cpu-idle-state-latencies-ns", 265 count) != 0) 266 goto out; 267 268 count = of_property_count_strings(power_mgt, 269 "ibm,cpu-idle-state-names"); 270 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", dt_idle_states, 271 "ibm,cpu-idle-state-names", 272 count) != 0) 273 goto out; 274 275 /* 276 * Since snooze is used as first idle state, max idle states allowed is 277 * CPUIDLE_STATE_MAX -1 278 */ 279 if (dt_idle_states > CPUIDLE_STATE_MAX - 1) { 280 pr_warn("cpuidle-powernv: discovered idle states more than allowed"); 281 dt_idle_states = CPUIDLE_STATE_MAX - 1; 282 } 283 284 if (of_property_read_u32_array(power_mgt, 285 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { 286 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n"); 287 goto out; 288 } 289 290 if (of_property_read_u32_array(power_mgt, 291 "ibm,cpu-idle-state-latencies-ns", latency_ns, 292 dt_idle_states)) { 293 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n"); 294 goto out; 295 } 296 if (of_property_read_string_array(power_mgt, 297 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) { 298 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n"); 299 goto out; 300 } 301 302 /* 303 * If the idle states use stop instruction, probe for psscr values 304 * and psscr mask which are necessary to specify required stop level. 305 */ 306 has_stop_states = (flags[0] & 307 (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)); 308 if (has_stop_states) { 309 count = of_property_count_u64_elems(power_mgt, 310 "ibm,cpu-idle-state-psscr"); 311 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", 312 dt_idle_states, 313 "ibm,cpu-idle-state-psscr", 314 count) != 0) 315 goto out; 316 317 count = of_property_count_u64_elems(power_mgt, 318 "ibm,cpu-idle-state-psscr-mask"); 319 if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", 320 dt_idle_states, 321 "ibm,cpu-idle-state-psscr-mask", 322 count) != 0) 323 goto out; 324 325 if (of_property_read_u64_array(power_mgt, 326 "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) { 327 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n"); 328 goto out; 329 } 330 331 if (of_property_read_u64_array(power_mgt, 332 "ibm,cpu-idle-state-psscr-mask", 333 psscr_mask, dt_idle_states)) { 334 pr_warn("cpuidle-powernv:Missing ibm,cpu-idle-state-psscr-mask in DT\n"); 335 goto out; 336 } 337 } 338 339 count = of_property_count_u32_elems(power_mgt, 340 "ibm,cpu-idle-state-residency-ns"); 341 342 if (count < 0) { 343 rc = count; 344 } else if (validate_dt_prop_sizes("ibm,cpu-idle-state-flags", 345 dt_idle_states, 346 "ibm,cpu-idle-state-residency-ns", 347 count) != 0) { 348 goto out; 349 } else { 350 rc = of_property_read_u32_array(power_mgt, 351 "ibm,cpu-idle-state-residency-ns", 352 residency_ns, dt_idle_states); 353 } 354 355 for (i = 0; i < dt_idle_states; i++) { 356 unsigned int exit_latency, target_residency; 357 /* 358 * If an idle state has exit latency beyond 359 * POWERNV_THRESHOLD_LATENCY_NS then don't use it 360 * in cpu-idle. 361 */ 362 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) 363 continue; 364 /* 365 * Firmware passes residency and latency values in ns. 366 * cpuidle expects it in us. 367 */ 368 exit_latency = latency_ns[i] / 1000; 369 if (!rc) 370 target_residency = residency_ns[i] / 1000; 371 else 372 target_residency = 0; 373 374 if (has_stop_states) { 375 int err = validate_psscr_val_mask(&psscr_val[i], 376 &psscr_mask[i], 377 flags[i]); 378 if (err) { 379 report_invalid_psscr_val(psscr_val[i], err); 380 continue; 381 } 382 } 383 384 /* 385 * For nap and fastsleep, use default target_residency 386 * values if f/w does not expose it. 387 */ 388 if (flags[i] & OPAL_PM_NAP_ENABLED) { 389 if (!rc) 390 target_residency = 100; 391 /* Add NAP state */ 392 add_powernv_state(nr_idle_states, "Nap", 393 CPUIDLE_FLAG_NONE, nap_loop, 394 target_residency, exit_latency, 0, 0); 395 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) && 396 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) { 397 add_powernv_state(nr_idle_states, names[i], 398 CPUIDLE_FLAG_NONE, stop_loop, 399 target_residency, exit_latency, 400 psscr_val[i], psscr_mask[i]); 401 } 402 403 /* 404 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come 405 * within this config dependency check. 406 */ 407 #ifdef CONFIG_TICK_ONESHOT 408 if (flags[i] & OPAL_PM_SLEEP_ENABLED || 409 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { 410 if (!rc) 411 target_residency = 300000; 412 /* Add FASTSLEEP state */ 413 add_powernv_state(nr_idle_states, "FastSleep", 414 CPUIDLE_FLAG_TIMER_STOP, 415 fastsleep_loop, 416 target_residency, exit_latency, 0, 0); 417 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) && 418 (flags[i] & OPAL_PM_TIMEBASE_STOP)) { 419 add_powernv_state(nr_idle_states, names[i], 420 CPUIDLE_FLAG_TIMER_STOP, stop_loop, 421 target_residency, exit_latency, 422 psscr_val[i], psscr_mask[i]); 423 } 424 #endif 425 nr_idle_states++; 426 } 427 out: 428 return nr_idle_states; 429 } 430 431 /* 432 * powernv_idle_probe() 433 * Choose state table for shared versus dedicated partition 434 */ 435 static int powernv_idle_probe(void) 436 { 437 if (cpuidle_disable != IDLE_NO_OVERRIDE) 438 return -ENODEV; 439 440 if (firmware_has_feature(FW_FEATURE_OPAL)) { 441 cpuidle_state_table = powernv_states; 442 /* Device tree can indicate more idle states */ 443 max_idle_state = powernv_add_idle_states(); 444 if (max_idle_state > 1) { 445 snooze_timeout_en = true; 446 snooze_timeout = powernv_states[1].target_residency * 447 tb_ticks_per_usec; 448 } 449 } else 450 return -ENODEV; 451 452 return 0; 453 } 454 455 static int __init powernv_processor_idle_init(void) 456 { 457 int retval; 458 459 retval = powernv_idle_probe(); 460 if (retval) 461 return retval; 462 463 powernv_cpuidle_driver_init(); 464 retval = cpuidle_register(&powernv_idle_driver, NULL); 465 if (retval) { 466 printk(KERN_DEBUG "Registration of powernv driver failed.\n"); 467 return retval; 468 } 469 470 retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 471 "cpuidle/powernv:online", 472 powernv_cpuidle_cpu_online, NULL); 473 WARN_ON(retval < 0); 474 retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, 475 "cpuidle/powernv:dead", NULL, 476 powernv_cpuidle_cpu_dead); 477 WARN_ON(retval < 0); 478 printk(KERN_DEBUG "powernv_idle_driver registered\n"); 479 return 0; 480 } 481 482 device_initcall(powernv_processor_idle_init); 483