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