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 MAX_POWERNV_IDLE_STATES 8 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 static u64 snooze_timeout; 33 static bool snooze_timeout_en; 34 35 static int snooze_loop(struct cpuidle_device *dev, 36 struct cpuidle_driver *drv, 37 int index) 38 { 39 u64 snooze_exit_time; 40 41 local_irq_enable(); 42 set_thread_flag(TIF_POLLING_NRFLAG); 43 44 snooze_exit_time = get_tb() + snooze_timeout; 45 ppc64_runlatch_off(); 46 while (!need_resched()) { 47 HMT_low(); 48 HMT_very_low(); 49 if (snooze_timeout_en && get_tb() > snooze_exit_time) 50 break; 51 } 52 53 HMT_medium(); 54 ppc64_runlatch_on(); 55 clear_thread_flag(TIF_POLLING_NRFLAG); 56 smp_mb(); 57 return index; 58 } 59 60 static int nap_loop(struct cpuidle_device *dev, 61 struct cpuidle_driver *drv, 62 int index) 63 { 64 ppc64_runlatch_off(); 65 power7_idle(); 66 ppc64_runlatch_on(); 67 return index; 68 } 69 70 /* Register for fastsleep only in oneshot mode of broadcast */ 71 #ifdef CONFIG_TICK_ONESHOT 72 static int fastsleep_loop(struct cpuidle_device *dev, 73 struct cpuidle_driver *drv, 74 int index) 75 { 76 unsigned long old_lpcr = mfspr(SPRN_LPCR); 77 unsigned long new_lpcr; 78 79 if (unlikely(system_state < SYSTEM_RUNNING)) 80 return index; 81 82 new_lpcr = old_lpcr; 83 /* Do not exit powersave upon decrementer as we've setup the timer 84 * offload. 85 */ 86 new_lpcr &= ~LPCR_PECE1; 87 88 mtspr(SPRN_LPCR, new_lpcr); 89 power7_sleep(); 90 91 mtspr(SPRN_LPCR, old_lpcr); 92 93 return index; 94 } 95 #endif 96 /* 97 * States for dedicated partition case. 98 */ 99 static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = { 100 { /* Snooze */ 101 .name = "snooze", 102 .desc = "snooze", 103 .exit_latency = 0, 104 .target_residency = 0, 105 .enter = &snooze_loop }, 106 }; 107 108 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n, 109 unsigned long action, void *hcpu) 110 { 111 int hotcpu = (unsigned long)hcpu; 112 struct cpuidle_device *dev = 113 per_cpu(cpuidle_devices, hotcpu); 114 115 if (dev && cpuidle_get_driver()) { 116 switch (action) { 117 case CPU_ONLINE: 118 case CPU_ONLINE_FROZEN: 119 cpuidle_pause_and_lock(); 120 cpuidle_enable_device(dev); 121 cpuidle_resume_and_unlock(); 122 break; 123 124 case CPU_DEAD: 125 case CPU_DEAD_FROZEN: 126 cpuidle_pause_and_lock(); 127 cpuidle_disable_device(dev); 128 cpuidle_resume_and_unlock(); 129 break; 130 131 default: 132 return NOTIFY_DONE; 133 } 134 } 135 return NOTIFY_OK; 136 } 137 138 static struct notifier_block setup_hotplug_notifier = { 139 .notifier_call = powernv_cpuidle_add_cpu_notifier, 140 }; 141 142 /* 143 * powernv_cpuidle_driver_init() 144 */ 145 static int powernv_cpuidle_driver_init(void) 146 { 147 int idle_state; 148 struct cpuidle_driver *drv = &powernv_idle_driver; 149 150 drv->state_count = 0; 151 152 for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { 153 /* Is the state not enabled? */ 154 if (cpuidle_state_table[idle_state].enter == NULL) 155 continue; 156 157 drv->states[drv->state_count] = /* structure copy */ 158 cpuidle_state_table[idle_state]; 159 160 drv->state_count += 1; 161 } 162 163 return 0; 164 } 165 166 static int powernv_add_idle_states(void) 167 { 168 struct device_node *power_mgt; 169 int nr_idle_states = 1; /* Snooze */ 170 int dt_idle_states; 171 u32 *latency_ns, *residency_ns, *flags; 172 int i, rc; 173 174 /* Currently we have snooze statically defined */ 175 176 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt"); 177 if (!power_mgt) { 178 pr_warn("opal: PowerMgmt Node not found\n"); 179 goto out; 180 } 181 182 /* Read values of any property to determine the num of idle states */ 183 dt_idle_states = of_property_count_u32_elems(power_mgt, "ibm,cpu-idle-state-flags"); 184 if (dt_idle_states < 0) { 185 pr_warn("cpuidle-powernv: no idle states found in the DT\n"); 186 goto out; 187 } 188 189 flags = kzalloc(sizeof(*flags) * dt_idle_states, GFP_KERNEL); 190 if (of_property_read_u32_array(power_mgt, 191 "ibm,cpu-idle-state-flags", flags, dt_idle_states)) { 192 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n"); 193 goto out_free_flags; 194 } 195 196 latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL); 197 rc = of_property_read_u32_array(power_mgt, 198 "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states); 199 if (rc) { 200 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n"); 201 goto out_free_latency; 202 } 203 204 residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL); 205 rc = of_property_read_u32_array(power_mgt, 206 "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states); 207 208 for (i = 0; i < dt_idle_states; i++) { 209 210 /* 211 * Cpuidle accepts exit_latency and target_residency in us. 212 * Use default target_residency values if f/w does not expose it. 213 */ 214 if (flags[i] & OPAL_PM_NAP_ENABLED) { 215 /* Add NAP state */ 216 strcpy(powernv_states[nr_idle_states].name, "Nap"); 217 strcpy(powernv_states[nr_idle_states].desc, "Nap"); 218 powernv_states[nr_idle_states].flags = 0; 219 powernv_states[nr_idle_states].target_residency = 100; 220 powernv_states[nr_idle_states].enter = &nap_loop; 221 } 222 223 /* 224 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come 225 * within this config dependency check. 226 */ 227 #ifdef CONFIG_TICK_ONESHOT 228 if (flags[i] & OPAL_PM_SLEEP_ENABLED || 229 flags[i] & OPAL_PM_SLEEP_ENABLED_ER1) { 230 /* Add FASTSLEEP state */ 231 strcpy(powernv_states[nr_idle_states].name, "FastSleep"); 232 strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); 233 powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP; 234 powernv_states[nr_idle_states].target_residency = 300000; 235 powernv_states[nr_idle_states].enter = &fastsleep_loop; 236 } 237 #endif 238 powernv_states[nr_idle_states].exit_latency = 239 ((unsigned int)latency_ns[i]) / 1000; 240 241 if (!rc) { 242 powernv_states[nr_idle_states].target_residency = 243 ((unsigned int)residency_ns[i]) / 1000; 244 } 245 246 nr_idle_states++; 247 } 248 249 kfree(residency_ns); 250 out_free_latency: 251 kfree(latency_ns); 252 out_free_flags: 253 kfree(flags); 254 out: 255 return nr_idle_states; 256 } 257 258 /* 259 * powernv_idle_probe() 260 * Choose state table for shared versus dedicated partition 261 */ 262 static int powernv_idle_probe(void) 263 { 264 if (cpuidle_disable != IDLE_NO_OVERRIDE) 265 return -ENODEV; 266 267 if (firmware_has_feature(FW_FEATURE_OPALv3)) { 268 cpuidle_state_table = powernv_states; 269 /* Device tree can indicate more idle states */ 270 max_idle_state = powernv_add_idle_states(); 271 if (max_idle_state > 1) { 272 snooze_timeout_en = true; 273 snooze_timeout = powernv_states[1].target_residency * 274 tb_ticks_per_usec; 275 } 276 } else 277 return -ENODEV; 278 279 return 0; 280 } 281 282 static int __init powernv_processor_idle_init(void) 283 { 284 int retval; 285 286 retval = powernv_idle_probe(); 287 if (retval) 288 return retval; 289 290 powernv_cpuidle_driver_init(); 291 retval = cpuidle_register(&powernv_idle_driver, NULL); 292 if (retval) { 293 printk(KERN_DEBUG "Registration of powernv driver failed.\n"); 294 return retval; 295 } 296 297 register_cpu_notifier(&setup_hotplug_notifier); 298 printk(KERN_DEBUG "powernv_idle_driver registered\n"); 299 return 0; 300 } 301 302 device_initcall(powernv_processor_idle_init); 303