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 static 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_cpu_online(unsigned int cpu) 123 { 124 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 125 126 if (dev && cpuidle_get_driver()) { 127 cpuidle_pause_and_lock(); 128 cpuidle_enable_device(dev); 129 cpuidle_resume_and_unlock(); 130 } 131 return 0; 132 } 133 134 static int powernv_cpuidle_cpu_dead(unsigned int cpu) 135 { 136 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); 137 138 if (dev && cpuidle_get_driver()) { 139 cpuidle_pause_and_lock(); 140 cpuidle_disable_device(dev); 141 cpuidle_resume_and_unlock(); 142 } 143 return 0; 144 } 145 146 /* 147 * powernv_cpuidle_driver_init() 148 */ 149 static int powernv_cpuidle_driver_init(void) 150 { 151 int idle_state; 152 struct cpuidle_driver *drv = &powernv_idle_driver; 153 154 drv->state_count = 0; 155 156 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { 157 /* Is the state not enabled? */ 158 if (cpuidle_state_table[idle_state].enter == NULL) 159 continue; 160 161 drv->states[drv->state_count] = /* structure copy */ 162 cpuidle_state_table[idle_state]; 163 164 drv->state_count += 1; 165 } 166 167 return 0; 168 } 169 170 static int powernv_add_idle_states(void) 171 { 172 struct device_node *power_mgt; 173 int nr_idle_states = 1; /* Snooze */ 174 int dt_idle_states; 175 u32 latency_ns[CPUIDLE_STATE_MAX]; 176 u32 residency_ns[CPUIDLE_STATE_MAX]; 177 u32 flags[CPUIDLE_STATE_MAX]; 178 u64 psscr_val[CPUIDLE_STATE_MAX]; 179 const char *names[CPUIDLE_STATE_MAX]; 180 int i, rc; 181 182 /* Currently we have snooze statically defined */ 183 184 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); 185 if (!power_mgt) { 186 pr_warn("opal: PowerMgmt Node not found\n"); 187 goto out; 188 } 189 190 /* Read values of any property to determine the num of idle states */ 191 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags"); 192 if (dt_idle_states < 0) { 193 pr_warn("cpuidle-powernv: no idle states found in the DT\n"); 194 goto out; 195 } 196 197 /* 198 * Since snooze is used as first idle state, max idle states allowed is 199 * CPUIDLE_STATE_MAX -1 200 */ 201 if (dt_idle_states > CPUIDLE_STATE_MAX - 1) { 202 pr_warn("cpuidle-powernv: discovered idle states more than allowed"); 203 dt_idle_states = CPUIDLE_STATE_MAX - 1; 204 } 205 206 if (of_property_read_u32_array(power_mgt, 207 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { 208 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n"); 209 goto out; 210 } 211 212 if (of_property_read_u32_array(power_mgt, 213 "ibm,cpu-idle-state-latencies-ns", latency_ns, 214 dt_idle_states)) { 215 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n"); 216 goto out; 217 } 218 if (of_property_read_string_array(power_mgt, 219 "ibm,cpu-idle-state-names", names, dt_idle_states) < 0) { 220 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n"); 221 goto out; 222 } 223 224 /* 225 * If the idle states use stop instruction, probe for psscr values 226 * which are necessary to specify required stop level. 227 */ 228 if (flags[0] & (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP)) 229 if (of_property_read_u64_array(power_mgt, 230 "ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states)) { 231 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n"); 232 goto out; 233 } 234 235 rc = of_property_read_u32_array(power_mgt, 236 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); 237 238 for (i = 0; i < dt_idle_states; i++) { 239 /* 240 * If an idle state has exit latency beyond 241 * POWERNV_THRESHOLD_LATENCY_NS then don't use it 242 * in cpu-idle. 243 */ 244 if (latency_ns[i] > POWERNV_THRESHOLD_LATENCY_NS) 245 continue; 246 247 /* 248 * Cpuidle accepts exit_latency and target_residency in us. 249 * Use default target_residency values if f/w does not expose it. 250 */ 251 if (flags[i] & OPAL_PM_NAP_ENABLED) { 252 /* Add NAP state */ 253 strcpy(powernv_states[nr_idle_states].name, "Nap"); 254 strcpy(powernv_states[nr_idle_states].desc, "Nap"); 255 powernv_states[nr_idle_states].flags = 0; 256 powernv_states[nr_idle_states].target_residency = 100; 257 powernv_states[nr_idle_states].enter = nap_loop; 258 } else if ((flags[i] & OPAL_PM_STOP_INST_FAST) && 259 !(flags[i] & OPAL_PM_TIMEBASE_STOP)) { 260 strncpy(powernv_states[nr_idle_states].name, 261 names[i], CPUIDLE_NAME_LEN); 262 strncpy(powernv_states[nr_idle_states].desc, 263 names[i], CPUIDLE_NAME_LEN); 264 powernv_states[nr_idle_states].flags = 0; 265 266 powernv_states[nr_idle_states].enter = stop_loop; 267 stop_psscr_table[nr_idle_states] = psscr_val[i]; 268 } 269 270 /* 271 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come 272 * within this config dependency check. 273 */ 274 #ifdef CONFIG_TICK_ONESHOT 275 if (flags[i] & OPAL_PM_SLEEP_ENABLED || 276 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { 277 /* Add FASTSLEEP state */ 278 strcpy(powernv_states[nr_idle_states].name, "FastSleep"); 279 strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); 280 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; 281 powernv_states[nr_idle_states].target_residency = 300000; 282 powernv_states[nr_idle_states].enter = fastsleep_loop; 283 } else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) && 284 (flags[i] & OPAL_PM_TIMEBASE_STOP)) { 285 strncpy(powernv_states[nr_idle_states].name, 286 names[i], CPUIDLE_NAME_LEN); 287 strncpy(powernv_states[nr_idle_states].desc, 288 names[i], CPUIDLE_NAME_LEN); 289 290 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; 291 powernv_states[nr_idle_states].enter = stop_loop; 292 stop_psscr_table[nr_idle_states] = psscr_val[i]; 293 } 294 #endif 295 powernv_states[nr_idle_states].exit_latency = 296 ((unsigned int)latency_ns[i]) / 1000; 297 298 if (!rc) { 299 powernv_states[nr_idle_states].target_residency = 300 ((unsigned int)residency_ns[i]) / 1000; 301 } 302 303 nr_idle_states++; 304 } 305 out: 306 return nr_idle_states; 307 } 308 309 /* 310 * powernv_idle_probe() 311 * Choose state table for shared versus dedicated partition 312 */ 313 static int powernv_idle_probe(void) 314 { 315 if (cpuidle_disable != IDLE_NO_OVERRIDE) 316 return -ENODEV; 317 318 if (firmware_has_feature(FW_FEATURE_OPAL)) { 319 cpuidle_state_table = powernv_states; 320 /* Device tree can indicate more idle states */ 321 max_idle_state = powernv_add_idle_states(); 322 if (max_idle_state > 1) { 323 snooze_timeout_en = true; 324 snooze_timeout = powernv_states[1].target_residency * 325 tb_ticks_per_usec; 326 } 327 } else 328 return -ENODEV; 329 330 return 0; 331 } 332 333 static int __init powernv_processor_idle_init(void) 334 { 335 int retval; 336 337 retval = powernv_idle_probe(); 338 if (retval) 339 return retval; 340 341 powernv_cpuidle_driver_init(); 342 retval = cpuidle_register(&powernv_idle_driver, NULL); 343 if (retval) { 344 printk(KERN_DEBUG "Registration of powernv driver failed.\n"); 345 return retval; 346 } 347 348 retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 349 "cpuidle/powernv:online", 350 powernv_cpuidle_cpu_online, NULL); 351 WARN_ON(retval < 0); 352 retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, 353 "cpuidle/powernv:dead", NULL, 354 powernv_cpuidle_cpu_dead); 355 WARN_ON(retval < 0); 356 printk(KERN_DEBUG "powernv_idle_driver registered\n"); 357 return 0; 358 } 359 360 device_initcall(powernv_processor_idle_init); 361