1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * cpuidle-powernv - idle state cpuidle driver. 4 * Adapted from drivers/cpuidle/cpuidle-pseries 5 * 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/moduleparam.h> 12 #include <linux/cpuidle.h> 13 #include <linux/cpu.h> 14 #include <linux/notifier.h> 15 #include <linux/clockchips.h> 16 #include <linux/of.h> 17 #include <linux/slab.h> 18 19 #include <asm/machdep.h> 20 #include <asm/firmware.h> 21 #include <asm/opal.h> 22 #include <asm/runlatch.h> 23 #include <asm/cpuidle.h> 24 25 /* 26 * Expose only those Hardware idle states via the cpuidle framework 27 * that have latency value below POWERNV_THRESHOLD_LATENCY_NS. 28 */ 29 #define POWERNV_THRESHOLD_LATENCY_NS 200000 30 31 static struct cpuidle_driver powernv_idle_driver = { 32 .name = "powernv_idle", 33 .owner = THIS_MODULE, 34 }; 35 36 static int max_idle_state __read_mostly; 37 static struct cpuidle_state *cpuidle_state_table __read_mostly; 38 39 struct stop_psscr_table { 40 u64 val; 41 u64 mask; 42 }; 43 44 static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly; 45 46 static u64 default_snooze_timeout __read_mostly; 47 static bool snooze_timeout_en __read_mostly; 48 49 static u64 get_snooze_timeout(struct cpuidle_device *dev, 50 struct cpuidle_driver *drv, 51 int index) 52 { 53 int i; 54 55 if (unlikely(!snooze_timeout_en)) 56 return default_snooze_timeout; 57 58 for (i = index + 1; i < drv->state_count; i++) { 59 struct cpuidle_state *s = &drv->states[i]; 60 struct cpuidle_state_usage *su = &dev->states_usage[i]; 61 62 if (s->disabled || su->disable) 63 continue; 64 65 return s->target_residency * tb_ticks_per_usec; 66 } 67 68 return default_snooze_timeout; 69 } 70 71 static int snooze_loop(struct cpuidle_device *dev, 72 struct cpuidle_driver *drv, 73 int index) 74 { 75 u64 snooze_exit_time; 76 77 set_thread_flag(TIF_POLLING_NRFLAG); 78 79 local_irq_enable(); 80 81 snooze_exit_time = get_tb() + get_snooze_timeout(dev, drv, index); 82 ppc64_runlatch_off(); 83 HMT_very_low(); 84 while (!need_resched()) { 85 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { 86 /* 87 * Task has not woken up but we are exiting the polling 88 * loop anyway. Require a barrier after polling is 89 * cleared to order subsequent test of need_resched(). 90 */ 91 clear_thread_flag(TIF_POLLING_NRFLAG); 92 smp_mb(); 93 break; 94 } 95 } 96 97 HMT_medium(); 98 ppc64_runlatch_on(); 99 clear_thread_flag(TIF_POLLING_NRFLAG); 100 101 local_irq_disable(); 102 103 return index; 104 } 105 106 static int nap_loop(struct cpuidle_device *dev, 107 struct cpuidle_driver *drv, 108 int index) 109 { 110 power7_idle_type(PNV_THREAD_NAP); 111 112 return index; 113 } 114 115 /* Register for fastsleep only in oneshot mode of broadcast */ 116 #ifdef CONFIG_TICK_ONESHOT 117 static int fastsleep_loop(struct cpuidle_device *dev, 118 struct cpuidle_driver *drv, 119 int index) 120 { 121 unsigned long old_lpcr = mfspr(SPRN_LPCR); 122 unsigned long new_lpcr; 123 124 if (unlikely(system_state < SYSTEM_RUNNING)) 125 return index; 126 127 new_lpcr = old_lpcr; 128 /* Do not exit powersave upon decrementer as we've setup the timer 129 * offload. 130 */ 131 new_lpcr &= ~LPCR_PECE1; 132 133 mtspr(SPRN_LPCR, new_lpcr); 134 135 power7_idle_type(PNV_THREAD_SLEEP); 136 137 mtspr(SPRN_LPCR, old_lpcr); 138 139 return index; 140 } 141 #endif 142 143 static int stop_loop(struct cpuidle_device *dev, 144 struct cpuidle_driver *drv, 145 int index) 146 { 147 power9_idle_type(stop_psscr_table[index].val, 148 stop_psscr_table[index].mask); 149 return index; 150 } 151 152 /* 153 * States for dedicated partition case. 154 */ 155 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = { 156 { /* Snooze */ 157 .name = "snooze", 158 .desc = "snooze", 159 .exit_latency = 0, 160 .target_residency = 0, 161 .enter = snooze_loop }, 162 }; 163 164 static int powernv_cpuidle_cpu_online(unsigned int cpu) 165 { 166 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 167 168 if (dev && cpuidle_get_driver()) { 169 cpuidle_pause_and_lock(); 170 cpuidle_enable_device(dev); 171 cpuidle_resume_and_unlock(); 172 } 173 return 0; 174 } 175 176 static int powernv_cpuidle_cpu_dead(unsigned int cpu) 177 { 178 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 179 180 if (dev && cpuidle_get_driver()) { 181 cpuidle_pause_and_lock(); 182 cpuidle_disable_device(dev); 183 cpuidle_resume_and_unlock(); 184 } 185 return 0; 186 } 187 188 /* 189 * powernv_cpuidle_driver_init() 190 */ 191 static int powernv_cpuidle_driver_init(void) 192 { 193 int idle_state; 194 struct cpuidle_driver *drv = &powernv_idle_driver; 195 196 drv->state_count = 0; 197 198 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { 199 /* Is the state not enabled? */ 200 if (cpuidle_state_table[idle_state].enter == NULL) 201 continue; 202 203 drv->states[drv->state_count] = /* structure copy */ 204 cpuidle_state_table[idle_state]; 205 206 drv->state_count += 1; 207 } 208 209 /* 210 * On the PowerNV platform cpu_present may be less than cpu_possible in 211 * cases when firmware detects the CPU, but it is not available to the 212 * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at 213 * run time and hence cpu_devices are not created for those CPUs by the 214 * generic topology_init(). 215 * 216 * drv->cpumask defaults to cpu_possible_mask in 217 * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where 218 * cpu_devices are not created for CPUs in cpu_possible_mask that 219 * cannot be hot-added later at run time. 220 * 221 * Trying cpuidle_register_device() on a CPU without a cpu_device is 222 * incorrect, so pass a correct CPU mask to the generic cpuidle driver. 223 */ 224 225 drv->cpumask = (struct cpumask *)cpu_present_mask; 226 227 return 0; 228 } 229 230 static inline void add_powernv_state(int index, const char *name, 231 unsigned int flags, 232 int (*idle_fn)(struct cpuidle_device *, 233 struct cpuidle_driver *, 234 int), 235 unsigned int target_residency, 236 unsigned int exit_latency, 237 u64 psscr_val, u64 psscr_mask) 238 { 239 strlcpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN); 240 strlcpy(powernv_states[index].desc, name, CPUIDLE_NAME_LEN); 241 powernv_states[index].flags = flags; 242 powernv_states[index].target_residency = target_residency; 243 powernv_states[index].exit_latency = exit_latency; 244 powernv_states[index].enter = idle_fn; 245 /* For power8 and below psscr_* will be 0 */ 246 stop_psscr_table[index].val = psscr_val; 247 stop_psscr_table[index].mask = psscr_mask; 248 } 249 250 /* 251 * Returns 0 if prop1_len == prop2_len. Else returns -1 252 */ 253 static inline int validate_dt_prop_sizes(const char *prop1, int prop1_len, 254 const char *prop2, int prop2_len) 255 { 256 if (prop1_len == prop2_len) 257 return 0; 258 259 pr_warn("cpuidle-powernv: array sizes don't match for %s and %s\n", 260 prop1, prop2); 261 return -1; 262 } 263 264 extern u32 pnv_get_supported_cpuidle_states(void); 265 static int powernv_add_idle_states(void) 266 { 267 int nr_idle_states = 1; /* Snooze */ 268 int dt_idle_states; 269 u32 has_stop_states = 0; 270 int i; 271 u32 supported_flags = pnv_get_supported_cpuidle_states(); 272 273 274 /* Currently we have snooze statically defined */ 275 if (nr_pnv_idle_states <= 0) { 276 pr_warn("cpuidle-powernv : Only Snooze is available\n"); 277 goto out; 278 } 279 280 /* TODO: Count only states which are eligible for cpuidle */ 281 dt_idle_states = nr_pnv_idle_states; 282 283 /* 284 * Since snooze is used as first idle state, max idle states allowed is 285 * CPUIDLE_STATE_MAX -1 286 */ 287 if (nr_pnv_idle_states > CPUIDLE_STATE_MAX - 1) { 288 pr_warn("cpuidle-powernv: discovered idle states more than allowed"); 289 dt_idle_states = CPUIDLE_STATE_MAX - 1; 290 } 291 292 /* 293 * If the idle states use stop instruction, probe for psscr values 294 * and psscr mask which are necessary to specify required stop level. 295 */ 296 has_stop_states = (pnv_idle_states[0].flags & 297 (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)); 298 299 for (i = 0; i < dt_idle_states; i++) { 300 unsigned int exit_latency, target_residency; 301 bool stops_timebase = false; 302 struct pnv_idle_states_t *state = &pnv_idle_states[i]; 303 304 /* 305 * Skip the platform idle state whose flag isn't in 306 * the supported_cpuidle_states flag mask. 307 */ 308 if ((state->flags & supported_flags) != state->flags) 309 continue; 310 /* 311 * If an idle state has exit latency beyond 312 * POWERNV_THRESHOLD_LATENCY_NS then don't use it 313 * in cpu-idle. 314 */ 315 if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS) 316 continue; 317 /* 318 * Firmware passes residency and latency values in ns. 319 * cpuidle expects it in us. 320 */ 321 exit_latency = DIV_ROUND_UP(state->latency_ns, 1000); 322 target_residency = DIV_ROUND_UP(state->residency_ns, 1000); 323 324 if (has_stop_states && !(state->valid)) 325 continue; 326 327 if (state->flags & OPAL_PM_TIMEBASE_STOP) 328 stops_timebase = true; 329 330 if (state->flags & OPAL_PM_NAP_ENABLED) { 331 /* Add NAP state */ 332 add_powernv_state(nr_idle_states, "Nap", 333 CPUIDLE_FLAG_NONE, nap_loop, 334 target_residency, exit_latency, 0, 0); 335 } else if (has_stop_states && !stops_timebase) { 336 add_powernv_state(nr_idle_states, state->name, 337 CPUIDLE_FLAG_NONE, stop_loop, 338 target_residency, exit_latency, 339 state->psscr_val, 340 state->psscr_mask); 341 } 342 343 /* 344 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come 345 * within this config dependency check. 346 */ 347 #ifdef CONFIG_TICK_ONESHOT 348 else if (state->flags & OPAL_PM_SLEEP_ENABLED || 349 state->flags & OPAL_PM_SLEEP_ENABLED_ER1) { 350 /* Add FASTSLEEP state */ 351 add_powernv_state(nr_idle_states, "FastSleep", 352 CPUIDLE_FLAG_TIMER_STOP, 353 fastsleep_loop, 354 target_residency, exit_latency, 0, 0); 355 } else if (has_stop_states && stops_timebase) { 356 add_powernv_state(nr_idle_states, state->name, 357 CPUIDLE_FLAG_TIMER_STOP, stop_loop, 358 target_residency, exit_latency, 359 state->psscr_val, 360 state->psscr_mask); 361 } 362 #endif 363 else 364 continue; 365 nr_idle_states++; 366 } 367 out: 368 return nr_idle_states; 369 } 370 371 /* 372 * powernv_idle_probe() 373 * Choose state table for shared versus dedicated partition 374 */ 375 static int powernv_idle_probe(void) 376 { 377 if (cpuidle_disable != IDLE_NO_OVERRIDE) 378 return -ENODEV; 379 380 if (firmware_has_feature(FW_FEATURE_OPAL)) { 381 cpuidle_state_table = powernv_states; 382 /* Device tree can indicate more idle states */ 383 max_idle_state = powernv_add_idle_states(); 384 default_snooze_timeout = TICK_USEC * tb_ticks_per_usec; 385 if (max_idle_state > 1) 386 snooze_timeout_en = true; 387 } else 388 return -ENODEV; 389 390 return 0; 391 } 392 393 static int __init powernv_processor_idle_init(void) 394 { 395 int retval; 396 397 retval = powernv_idle_probe(); 398 if (retval) 399 return retval; 400 401 powernv_cpuidle_driver_init(); 402 retval = cpuidle_register(&powernv_idle_driver, NULL); 403 if (retval) { 404 printk(KERN_DEBUG "Registration of powernv driver failed.\n"); 405 return retval; 406 } 407 408 retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 409 "cpuidle/powernv:online", 410 powernv_cpuidle_cpu_online, NULL); 411 WARN_ON(retval < 0); 412 retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, 413 "cpuidle/powernv:dead", NULL, 414 powernv_cpuidle_cpu_dead); 415 WARN_ON(retval < 0); 416 printk(KERN_DEBUG "powernv_idle_driver registered\n"); 417 return 0; 418 } 419 420 device_initcall(powernv_processor_idle_init); 421