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1// SPDX-License-Identifier: GPL-2.02/*3 * cpuidle-powernv - idle state cpuidle driver.4 * Adapted from drivers/cpuidle/cpuidle-pseries5 *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 framework27 * that have latency value below POWERNV_THRESHOLD_LATENCY_NS.28 */29#define POWERNV_THRESHOLD_LATENCY_NS 20000030 31static struct cpuidle_driver powernv_idle_driver = {32 .name = "powernv_idle",33 .owner = THIS_MODULE,34};35 36static int max_idle_state __read_mostly;37static struct cpuidle_state *cpuidle_state_table __read_mostly;38 39struct stop_psscr_table {40 u64 val;41 u64 mask;42};43 44static struct stop_psscr_table stop_psscr_table[CPUIDLE_STATE_MAX] __read_mostly;45 46static u64 default_snooze_timeout __read_mostly;47static bool snooze_timeout_en __read_mostly;48 49static 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 if (dev->states_usage[i].disable)60 continue;61 62 return drv->states[i].target_residency * tb_ticks_per_usec;63 }64 65 return default_snooze_timeout;66}67 68static int snooze_loop(struct cpuidle_device *dev,69 struct cpuidle_driver *drv,70 int index)71{72 u64 snooze_exit_time;73 74 set_thread_flag(TIF_POLLING_NRFLAG);75 76 local_irq_enable();77 78 snooze_exit_time = get_tb() + get_snooze_timeout(dev, drv, index);79 dev->poll_time_limit = false;80 ppc64_runlatch_off();81 HMT_very_low();82 while (!need_resched()) {83 if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) {84 /*85 * Task has not woken up but we are exiting the polling86 * loop anyway. Require a barrier after polling is87 * cleared to order subsequent test of need_resched().88 */89 clear_thread_flag(TIF_POLLING_NRFLAG);90 dev->poll_time_limit = true;91 smp_mb();92 break;93 }94 }95 96 HMT_medium();97 ppc64_runlatch_on();98 clear_thread_flag(TIF_POLLING_NRFLAG);99 100 local_irq_disable();101 102 return index;103}104 105static int nap_loop(struct cpuidle_device *dev,106 struct cpuidle_driver *drv,107 int index)108{109 power7_idle_type(PNV_THREAD_NAP);110 111 return index;112}113 114/* Register for fastsleep only in oneshot mode of broadcast */115#ifdef CONFIG_TICK_ONESHOT116static int fastsleep_loop(struct cpuidle_device *dev,117 struct cpuidle_driver *drv,118 int index)119{120 unsigned long old_lpcr = mfspr(SPRN_LPCR);121 unsigned long new_lpcr;122 123 if (unlikely(system_state < SYSTEM_RUNNING))124 return index;125 126 new_lpcr = old_lpcr;127 /* Do not exit powersave upon decrementer as we've setup the timer128 * offload.129 */130 new_lpcr &= ~LPCR_PECE1;131 132 mtspr(SPRN_LPCR, new_lpcr);133 134 power7_idle_type(PNV_THREAD_SLEEP);135 136 mtspr(SPRN_LPCR, old_lpcr);137 138 return index;139}140#endif141 142static int stop_loop(struct cpuidle_device *dev,143 struct cpuidle_driver *drv,144 int index)145{146 arch300_idle_type(stop_psscr_table[index].val,147 stop_psscr_table[index].mask);148 return index;149}150 151/*152 * States for dedicated partition case.153 */154static struct cpuidle_state powernv_states[CPUIDLE_STATE_MAX] = {155 { /* Snooze */156 .name = "snooze",157 .desc = "snooze",158 .exit_latency = 0,159 .target_residency = 0,160 .enter = snooze_loop,161 .flags = CPUIDLE_FLAG_POLLING },162};163 164static 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 176static 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 */191static 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 in211 * cases when firmware detects the CPU, but it is not available to the212 * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at213 * run time and hence cpu_devices are not created for those CPUs by the214 * generic topology_init().215 *216 * drv->cpumask defaults to cpu_possible_mask in217 * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where218 * cpu_devices are not created for CPUs in cpu_possible_mask that219 * cannot be hot-added later at run time.220 *221 * Trying cpuidle_register_device() on a CPU without a cpu_device is222 * 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 230static 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 strscpy(powernv_states[index].name, name, CPUIDLE_NAME_LEN);240 strscpy(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 250extern u32 pnv_get_supported_cpuidle_states(void);251static int powernv_add_idle_states(void)252{253 int nr_idle_states = 1; /* Snooze */254 int dt_idle_states;255 u32 has_stop_states = 0;256 int i;257 u32 supported_flags = pnv_get_supported_cpuidle_states();258 259 260 /* Currently we have snooze statically defined */261 if (nr_pnv_idle_states <= 0) {262 pr_warn("cpuidle-powernv : Only Snooze is available\n");263 goto out;264 }265 266 /* TODO: Count only states which are eligible for cpuidle */267 dt_idle_states = nr_pnv_idle_states;268 269 /*270 * Since snooze is used as first idle state, max idle states allowed is271 * CPUIDLE_STATE_MAX -1272 */273 if (nr_pnv_idle_states > CPUIDLE_STATE_MAX - 1) {274 pr_warn("cpuidle-powernv: discovered idle states more than allowed");275 dt_idle_states = CPUIDLE_STATE_MAX - 1;276 }277 278 /*279 * If the idle states use stop instruction, probe for psscr values280 * and psscr mask which are necessary to specify required stop level.281 */282 has_stop_states = (pnv_idle_states[0].flags &283 (OPAL_PM_STOP_INST_FAST | OPAL_PM_STOP_INST_DEEP));284 285 for (i = 0; i < dt_idle_states; i++) {286 unsigned int exit_latency, target_residency;287 bool stops_timebase = false;288 struct pnv_idle_states_t *state = &pnv_idle_states[i];289 290 /*291 * Skip the platform idle state whose flag isn't in292 * the supported_cpuidle_states flag mask.293 */294 if ((state->flags & supported_flags) != state->flags)295 continue;296 /*297 * If an idle state has exit latency beyond298 * POWERNV_THRESHOLD_LATENCY_NS then don't use it299 * in cpu-idle.300 */301 if (state->latency_ns > POWERNV_THRESHOLD_LATENCY_NS)302 continue;303 /*304 * Firmware passes residency and latency values in ns.305 * cpuidle expects it in us.306 */307 exit_latency = DIV_ROUND_UP(state->latency_ns, 1000);308 target_residency = DIV_ROUND_UP(state->residency_ns, 1000);309 310 if (has_stop_states && !(state->valid))311 continue;312 313 if (state->flags & OPAL_PM_TIMEBASE_STOP)314 stops_timebase = true;315 316 if (state->flags & OPAL_PM_NAP_ENABLED) {317 /* Add NAP state */318 add_powernv_state(nr_idle_states, "Nap",319 CPUIDLE_FLAG_NONE, nap_loop,320 target_residency, exit_latency, 0, 0);321 } else if (has_stop_states && !stops_timebase) {322 add_powernv_state(nr_idle_states, state->name,323 CPUIDLE_FLAG_NONE, stop_loop,324 target_residency, exit_latency,325 state->psscr_val,326 state->psscr_mask);327 }328 329 /*330 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come331 * within this config dependency check.332 */333#ifdef CONFIG_TICK_ONESHOT334 else if (state->flags & OPAL_PM_SLEEP_ENABLED ||335 state->flags & OPAL_PM_SLEEP_ENABLED_ER1) {336 /* Add FASTSLEEP state */337 add_powernv_state(nr_idle_states, "FastSleep",338 CPUIDLE_FLAG_TIMER_STOP,339 fastsleep_loop,340 target_residency, exit_latency, 0, 0);341 } else if (has_stop_states && stops_timebase) {342 add_powernv_state(nr_idle_states, state->name,343 CPUIDLE_FLAG_TIMER_STOP, stop_loop,344 target_residency, exit_latency,345 state->psscr_val,346 state->psscr_mask);347 }348#endif349 else350 continue;351 nr_idle_states++;352 }353out:354 return nr_idle_states;355}356 357/*358 * powernv_idle_probe()359 * Choose state table for shared versus dedicated partition360 */361static int powernv_idle_probe(void)362{363 if (cpuidle_disable != IDLE_NO_OVERRIDE)364 return -ENODEV;365 366 if (firmware_has_feature(FW_FEATURE_OPAL)) {367 cpuidle_state_table = powernv_states;368 /* Device tree can indicate more idle states */369 max_idle_state = powernv_add_idle_states();370 default_snooze_timeout = TICK_USEC * tb_ticks_per_usec;371 if (max_idle_state > 1)372 snooze_timeout_en = true;373 } else374 return -ENODEV;375 376 return 0;377}378 379static int __init powernv_processor_idle_init(void)380{381 int retval;382 383 retval = powernv_idle_probe();384 if (retval)385 return retval;386 387 powernv_cpuidle_driver_init();388 retval = cpuidle_register(&powernv_idle_driver, NULL);389 if (retval) {390 printk(KERN_DEBUG "Registration of powernv driver failed.\n");391 return retval;392 }393 394 retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,395 "cpuidle/powernv:online",396 powernv_cpuidle_cpu_online, NULL);397 WARN_ON(retval < 0);398 retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,399 "cpuidle/powernv:dead", NULL,400 powernv_cpuidle_cpu_dead);401 WARN_ON(retval < 0);402 printk(KERN_DEBUG "powernv_idle_driver registered\n");403 return 0;404}405 406device_initcall(powernv_processor_idle_init);407