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 23 #define POWERNV_THRESHOLD_LATENCY_NS 200000 24 25 struct cpuidle_driver powernv_idle_driver = { 26 .name = "powernv_idle", 27 .owner = THIS_MODULE, 28 }; 29 30 static int max_idle_state; 31 static struct cpuidle_state *cpuidle_state_table; 32 33 static u64 stop_psscr_table[CPUIDLE_STATE_MAX]; 34 35 static u64 snooze_timeout; 36 static bool snooze_timeout_en; 37 38 static int snooze_loop(struct cpuidle_device *dev, 39 struct cpuidle_driver *drv, 40 int index) 41 { 42 u64 snooze_exit_time; 43 44 local_irq_enable(); 45 set_thread_flag(TIF_POLLING_NRFLAG); 46 47 snooze_exit_time = get_tb() + snooze_timeout; 48 ppc64_runlatch_off(); 49 while (!need_resched()) { 50 HMT_low(); 51 HMT_very_low(); 52 if (snooze_timeout_en && get_tb() > snooze_exit_time) 53 break; 54 } 55 56 HMT_medium(); 57 ppc64_runlatch_on(); 58 clear_thread_flag(TIF_POLLING_NRFLAG); 59 smp_mb(); 60 return index; 61 } 62 63 static int nap_loop(struct cpuidle_device *dev, 64 struct cpuidle_driver *drv, 65 int index) 66 { 67 ppc64_runlatch_off(); 68 power7_idle(); 69 ppc64_runlatch_on(); 70 return index; 71 } 72 73 /* Register for fastsleep only in oneshot mode of broadcast */ 74 #ifdef CONFIG_TICK_ONESHOT 75 static int fastsleep_loop(struct cpuidle_device *dev, 76 struct cpuidle_driver *drv, 77 int index) 78 { 79 unsigned long old_lpcr = mfspr(SPRN_LPCR); 80 unsigned long new_lpcr; 81 82 if (unlikely(system_state < SYSTEM_RUNNING)) 83 return index; 84 85 new_lpcr = old_lpcr; 86 /* Do not exit powersave upon decrementer as we've setup the timer 87 * offload. 88 */ 89 new_lpcr &= ~LPCR_PECE1; 90 91 mtspr(SPRN_LPCR, new_lpcr); 92 power7_sleep(); 93 94 mtspr(SPRN_LPCR, old_lpcr); 95 96 return index; 97 } 98 #endif 99 100 static int stop_loop(struct cpuidle_device *dev, 101 struct cpuidle_driver *drv, 102 int index) 103 { 104 ppc64_runlatch_off(); 105 power9_idle_stop(stop_psscr_table[index]); 106 ppc64_runlatch_on(); 107 return index; 108 } 109 110 /* 111 * States for dedicated partition case. 112 */ 113 static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = { 114 { /* Snooze */ 115 .name = "snooze", 116 .desc = "snooze", 117 .exit_latency = 0, 118 .target_residency = 0, 119 .enter = snooze_loop }, 120 }; 121 122 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n, 123 unsigned long action, void *hcpu) 124 { 125 int hotcpu = (unsigned long)hcpu; 126 struct cpuidle_device *dev = 127 per_cpu(cpuidle_devices, hotcpu); 128 129 if (dev && cpuidle_get_driver()) { 130 switch (action) { 131 case CPU_ONLINE: 132 case CPU_ONLINE_FROZEN: 133 cpuidle_pause_and_lock(); 134 cpuidle_enable_device(dev); 135 cpuidle_resume_and_unlock(); 136 break; 137 138 case CPU_DEAD: 139 case CPU_DEAD_FROZEN: 140 cpuidle_pause_and_lock(); 141 cpuidle_disable_device(dev); 142 cpuidle_resume_and_unlock(); 143 break; 144 145 default: 146 return NOTIFY_DONE; 147 } 148 } 149 return NOTIFY_OK; 150 } 151 152 static struct notifier_block setup_hotplug_notifier = { 153 .notifier_call = powernv_cpuidle_add_cpu_notifier, 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 return 0; 178 } 179 180 static int powernv_add_idle_states(void) 181 { 182 struct device_node *power_mgt; 183 int nr_idle_states = 1; /* Snooze */ 184 int dt_idle_states; 185 u32 latency_ns[CPUIDLE_STATE_MAX]; 186 u32 residency_ns[CPUIDLE_STATE_MAX]; 187 u32 flags[CPUIDLE_STATE_MAX]; 188 u64 psscr_val[CPUIDLE_STATE_MAX]; 189 const char *names[CPUIDLE_STATE_MAX]; 190 int i, rc; 191 192 /* Currently we have snooze statically defined */ 193 194 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); 195 if (!power_mgt) { 196 pr_warn("opal: PowerMgmt Node not found\n"); 197 goto out; 198 } 199 200 /* Read values of any property to determine the num of idle states */ 201 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags"); 202 if (dt_idle_states < 0) { 203 pr_warn("cpuidle-powernv: no idle states found in the DT\n"); 204 goto out; 205 } 206 207 /* 208 * Since snooze is used as first idle state, max idle states allowed is 209 * CPUIDLE_STATE_MAX -1 210 */ 211 if (dt_idle_states > CPUIDLE_STATE_MAX - 1) { 212 pr_warn("cpuidle-powernv: discovered idle states more than allowed"); 213 dt_idle_states = CPUIDLE_STATE_MAX - 1; 214 } 215 216 if (of_property_read_u32_array(power_mgt, 217 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { 218 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n"); 219 goto out; 220 } 221 222 if (of_property_read_u32_array(power_mgt, 223 "ibm,cpu-idle-state-latencies-ns", latency_ns, 224 dt_idle_states)) { 225 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n"); 226 goto out; 227 } 228 if (of_property_read_string_array(power_mgt, 229 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) { 230 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n"); 231 goto out; 232 } 233 234 /* 235 * If the idle states use stop instruction, probe for psscr values 236 * which are necessary to specify required stop level. 237 */ 238 if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)) 239 if (of_property_read_u64_array(power_mgt, 240 "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) { 241 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n"); 242 goto out; 243 } 244 245 rc = of_property_read_u32_array(power_mgt, 246 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); 247 248 for (i = 0; i < dt_idle_states; i++) { 249 /* 250 * If an idle state has exit latency beyond 251 * POWERNV_THRESHOLD_LATENCY_NS then don't use it 252 * in cpu-idle. 253 */ 254 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) 255 continue; 256 257 /* 258 * Cpuidle accepts exit_latency and target_residency in us. 259 * Use default target_residency values if f/w does not expose it. 260 */ 261 if (flags[i] & OPAL_PM_NAP_ENABLED) { 262 /* Add NAP state */ 263 strcpy(powernv_states[nr_idle_states].name, "Nap"); 264 strcpy(powernv_states[nr_idle_states].desc, "Nap"); 265 powernv_states[nr_idle_states].flags = 0; 266 powernv_states[nr_idle_states].target_residency = 100; 267 powernv_states[nr_idle_states].enter = nap_loop; 268 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) && 269 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) { 270 strncpy(powernv_states[nr_idle_states].name, 271 names[i], CPUIDLE_NAME_LEN); 272 strncpy(powernv_states[nr_idle_states].desc, 273 names[i], CPUIDLE_NAME_LEN); 274 powernv_states[nr_idle_states].flags = 0; 275 276 powernv_states[nr_idle_states].enter = stop_loop; 277 stop_psscr_table[nr_idle_states] = psscr_val[i]; 278 } 279 280 /* 281 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come 282 * within this config dependency check. 283 */ 284 #ifdef CONFIG_TICK_ONESHOT 285 if (flags[i] & OPAL_PM_SLEEP_ENABLED || 286 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { 287 /* Add FASTSLEEP state */ 288 strcpy(powernv_states[nr_idle_states].name, "FastSleep"); 289 strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); 290 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; 291 powernv_states[nr_idle_states].target_residency = 300000; 292 powernv_states[nr_idle_states].enter = fastsleep_loop; 293 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) && 294 (flags[i] & OPAL_PM_TIMEBASE_STOP)) { 295 strncpy(powernv_states[nr_idle_states].name, 296 names[i], CPUIDLE_NAME_LEN); 297 strncpy(powernv_states[nr_idle_states].desc, 298 names[i], CPUIDLE_NAME_LEN); 299 300 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; 301 powernv_states[nr_idle_states].enter = stop_loop; 302 stop_psscr_table[nr_idle_states] = psscr_val[i]; 303 } 304 #endif 305 powernv_states[nr_idle_states].exit_latency = 306 ((unsigned int)latency_ns[i]) / 1000; 307 308 if (!rc) { 309 powernv_states[nr_idle_states].target_residency = 310 ((unsigned int)residency_ns[i]) / 1000; 311 } 312 313 nr_idle_states++; 314 } 315 out: 316 return nr_idle_states; 317 } 318 319 /* 320 * powernv_idle_probe() 321 * Choose state table for shared versus dedicated partition 322 */ 323 static int powernv_idle_probe(void) 324 { 325 if (cpuidle_disable != IDLE_NO_OVERRIDE) 326 return -ENODEV; 327 328 if (firmware_has_feature(FW_FEATURE_OPAL)) { 329 cpuidle_state_table = powernv_states; 330 /* Device tree can indicate more idle states */ 331 max_idle_state = powernv_add_idle_states(); 332 if (max_idle_state > 1) { 333 snooze_timeout_en = true; 334 snooze_timeout = powernv_states[1].target_residency * 335 tb_ticks_per_usec; 336 } 337 } else 338 return -ENODEV; 339 340 return 0; 341 } 342 343 static int __init powernv_processor_idle_init(void) 344 { 345 int retval; 346 347 retval = powernv_idle_probe(); 348 if (retval) 349 return retval; 350 351 powernv_cpuidle_driver_init(); 352 retval = cpuidle_register(&powernv_idle_driver, NULL); 353 if (retval) { 354 printk(KERN_DEBUG "Registration of powernv driver failed.\n"); 355 return retval; 356 } 357 358 register_cpu_notifier(&setup_hotplug_notifier); 359 printk(KERN_DEBUG "powernv_idle_driver registered\n"); 360 return 0; 361 } 362 363 device_initcall(powernv_processor_idle_init); 364