Merge remote-tracking branch 'spi/for-next'
[deliverable/linux.git] / drivers / cpuidle / cpuidle-powernv.c
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);
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