Commit | Line | Data |
---|---|---|
707827f3 | 1 | /* |
962e7bd4 | 2 | * cpuidle-pseries - idle state cpuidle driver. |
707827f3 DD |
3 | * Adapted from drivers/idle/intel_idle.c and |
4 | * drivers/acpi/processor_idle.c | |
5 | * | |
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> | |
16aaaff6 | 14 | #include <linux/notifier.h> |
707827f3 DD |
15 | |
16 | #include <asm/paca.h> | |
17 | #include <asm/reg.h> | |
707827f3 DD |
18 | #include <asm/machdep.h> |
19 | #include <asm/firmware.h> | |
212bebb4 | 20 | #include <asm/plpar_wrappers.h> |
707827f3 DD |
21 | |
22 | struct cpuidle_driver pseries_idle_driver = { | |
1ca80944 DL |
23 | .name = "pseries_idle", |
24 | .owner = THIS_MODULE, | |
707827f3 DD |
25 | }; |
26 | ||
27 | #define MAX_IDLE_STATE_COUNT 2 | |
28 | ||
29 | static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; | |
962e7bd4 | 30 | static struct cpuidle_device __percpu *pseries_cpuidle_devices; |
707827f3 DD |
31 | static struct cpuidle_state *cpuidle_state_table; |
32 | ||
1ca80944 | 33 | static inline void idle_loop_prolog(unsigned long *in_purr) |
707827f3 | 34 | { |
707827f3 DD |
35 | *in_purr = mfspr(SPRN_PURR); |
36 | /* | |
37 | * Indicate to the HV that we are idle. Now would be | |
38 | * a good time to find other work to dispatch. | |
39 | */ | |
40 | get_lppaca()->idle = 1; | |
41 | } | |
42 | ||
1ca80944 | 43 | static inline void idle_loop_epilog(unsigned long in_purr) |
707827f3 | 44 | { |
7ffcf8ec AB |
45 | u64 wait_cycles; |
46 | ||
47 | wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles); | |
48 | wait_cycles += mfspr(SPRN_PURR) - in_purr; | |
49 | get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); | |
707827f3 | 50 | get_lppaca()->idle = 0; |
707827f3 DD |
51 | } |
52 | ||
53 | static int snooze_loop(struct cpuidle_device *dev, | |
54 | struct cpuidle_driver *drv, | |
55 | int index) | |
56 | { | |
57 | unsigned long in_purr; | |
83dac594 | 58 | int cpu = dev->cpu; |
707827f3 | 59 | |
1ca80944 | 60 | idle_loop_prolog(&in_purr); |
83dac594 DD |
61 | local_irq_enable(); |
62 | set_thread_flag(TIF_POLLING_NRFLAG); | |
707827f3 | 63 | |
83dac594 | 64 | while ((!need_resched()) && cpu_online(cpu)) { |
83dac594 DD |
65 | HMT_low(); |
66 | HMT_very_low(); | |
707827f3 DD |
67 | } |
68 | ||
707827f3 | 69 | HMT_medium(); |
83dac594 DD |
70 | clear_thread_flag(TIF_POLLING_NRFLAG); |
71 | smp_mb(); | |
72 | ||
1ca80944 DL |
73 | idle_loop_epilog(in_purr); |
74 | ||
707827f3 DD |
75 | return index; |
76 | } | |
77 | ||
7230c564 BH |
78 | static void check_and_cede_processor(void) |
79 | { | |
80 | /* | |
be2cf20a BH |
81 | * Ensure our interrupt state is properly tracked, |
82 | * also checks if no interrupt has occurred while we | |
83 | * were soft-disabled | |
7230c564 | 84 | */ |
be2cf20a | 85 | if (prep_irq_for_idle()) { |
7230c564 | 86 | cede_processor(); |
be2cf20a BH |
87 | #ifdef CONFIG_TRACE_IRQFLAGS |
88 | /* Ensure that H_CEDE returns with IRQs on */ | |
89 | if (WARN_ON(!(mfmsr() & MSR_EE))) | |
90 | __hard_irq_enable(); | |
91 | #endif | |
92 | } | |
7230c564 BH |
93 | } |
94 | ||
707827f3 DD |
95 | static int dedicated_cede_loop(struct cpuidle_device *dev, |
96 | struct cpuidle_driver *drv, | |
97 | int index) | |
98 | { | |
99 | unsigned long in_purr; | |
707827f3 | 100 | |
1ca80944 | 101 | idle_loop_prolog(&in_purr); |
707827f3 DD |
102 | get_lppaca()->donate_dedicated_cpu = 1; |
103 | ||
707827f3 | 104 | HMT_medium(); |
7230c564 | 105 | check_and_cede_processor(); |
707827f3 DD |
106 | |
107 | get_lppaca()->donate_dedicated_cpu = 0; | |
1ca80944 DL |
108 | |
109 | idle_loop_epilog(in_purr); | |
110 | ||
707827f3 DD |
111 | return index; |
112 | } | |
113 | ||
114 | static int shared_cede_loop(struct cpuidle_device *dev, | |
115 | struct cpuidle_driver *drv, | |
116 | int index) | |
117 | { | |
118 | unsigned long in_purr; | |
707827f3 | 119 | |
1ca80944 | 120 | idle_loop_prolog(&in_purr); |
707827f3 DD |
121 | |
122 | /* | |
123 | * Yield the processor to the hypervisor. We return if | |
124 | * an external interrupt occurs (which are driven prior | |
125 | * to returning here) or if a prod occurs from another | |
126 | * processor. When returning here, external interrupts | |
127 | * are enabled. | |
128 | */ | |
7230c564 | 129 | check_and_cede_processor(); |
707827f3 | 130 | |
1ca80944 DL |
131 | idle_loop_epilog(in_purr); |
132 | ||
707827f3 DD |
133 | return index; |
134 | } | |
135 | ||
136 | /* | |
137 | * States for dedicated partition case. | |
138 | */ | |
139 | static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { | |
140 | { /* Snooze */ | |
141 | .name = "snooze", | |
142 | .desc = "snooze", | |
143 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
144 | .exit_latency = 0, | |
145 | .target_residency = 0, | |
146 | .enter = &snooze_loop }, | |
147 | { /* CEDE */ | |
148 | .name = "CEDE", | |
149 | .desc = "CEDE", | |
150 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
83dac594 DD |
151 | .exit_latency = 10, |
152 | .target_residency = 100, | |
707827f3 DD |
153 | .enter = &dedicated_cede_loop }, |
154 | }; | |
155 | ||
156 | /* | |
157 | * States for shared partition case. | |
158 | */ | |
159 | static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { | |
160 | { /* Shared Cede */ | |
161 | .name = "Shared Cede", | |
162 | .desc = "Shared Cede", | |
163 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
164 | .exit_latency = 0, | |
165 | .target_residency = 0, | |
166 | .enter = &shared_cede_loop }, | |
167 | }; | |
168 | ||
8ea959a1 DD |
169 | void update_smt_snooze_delay(int cpu, int residency) |
170 | { | |
171 | struct cpuidle_driver *drv = cpuidle_get_driver(); | |
172 | struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); | |
173 | ||
174 | if (cpuidle_state_table != dedicated_states) | |
175 | return; | |
176 | ||
177 | if (residency < 0) { | |
178 | /* Disable the Nap state on that cpu */ | |
179 | if (dev) | |
180 | dev->states_usage[1].disable = 1; | |
181 | } else | |
182 | if (drv) | |
83dac594 | 183 | drv->states[1].target_residency = residency; |
8ea959a1 DD |
184 | } |
185 | ||
16aaaff6 DD |
186 | static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, |
187 | unsigned long action, void *hcpu) | |
707827f3 | 188 | { |
16aaaff6 | 189 | int hotcpu = (unsigned long)hcpu; |
707827f3 | 190 | struct cpuidle_device *dev = |
962e7bd4 | 191 | per_cpu_ptr(pseries_cpuidle_devices, hotcpu); |
16aaaff6 | 192 | |
852d8cb1 DD |
193 | if (dev && cpuidle_get_driver()) { |
194 | switch (action) { | |
195 | case CPU_ONLINE: | |
196 | case CPU_ONLINE_FROZEN: | |
197 | cpuidle_pause_and_lock(); | |
16aaaff6 | 198 | cpuidle_enable_device(dev); |
852d8cb1 DD |
199 | cpuidle_resume_and_unlock(); |
200 | break; | |
201 | ||
202 | case CPU_DEAD: | |
203 | case CPU_DEAD_FROZEN: | |
204 | cpuidle_pause_and_lock(); | |
205 | cpuidle_disable_device(dev); | |
206 | cpuidle_resume_and_unlock(); | |
207 | break; | |
208 | ||
209 | default: | |
210 | return NOTIFY_DONE; | |
16aaaff6 | 211 | } |
707827f3 | 212 | } |
16aaaff6 | 213 | return NOTIFY_OK; |
707827f3 DD |
214 | } |
215 | ||
16aaaff6 DD |
216 | static struct notifier_block setup_hotplug_notifier = { |
217 | .notifier_call = pseries_cpuidle_add_cpu_notifier, | |
218 | }; | |
219 | ||
707827f3 DD |
220 | /* |
221 | * pseries_cpuidle_driver_init() | |
222 | */ | |
223 | static int pseries_cpuidle_driver_init(void) | |
224 | { | |
225 | int idle_state; | |
226 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
227 | ||
228 | drv->state_count = 0; | |
229 | ||
230 | for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { | |
231 | ||
232 | if (idle_state > max_idle_state) | |
233 | break; | |
234 | ||
235 | /* is the state not enabled? */ | |
236 | if (cpuidle_state_table[idle_state].enter == NULL) | |
237 | continue; | |
238 | ||
239 | drv->states[drv->state_count] = /* structure copy */ | |
240 | cpuidle_state_table[idle_state]; | |
241 | ||
707827f3 DD |
242 | drv->state_count += 1; |
243 | } | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
962e7bd4 DD |
248 | /* pseries_idle_devices_uninit(void) |
249 | * unregister cpuidle devices and de-allocate memory | |
250 | */ | |
251 | static void pseries_idle_devices_uninit(void) | |
252 | { | |
253 | int i; | |
254 | struct cpuidle_device *dev; | |
255 | ||
256 | for_each_possible_cpu(i) { | |
257 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
258 | cpuidle_unregister_device(dev); | |
259 | } | |
260 | ||
261 | free_percpu(pseries_cpuidle_devices); | |
262 | return; | |
263 | } | |
264 | ||
265 | /* pseries_idle_devices_init() | |
266 | * allocate, initialize and register cpuidle device | |
267 | */ | |
268 | static int pseries_idle_devices_init(void) | |
269 | { | |
270 | int i; | |
271 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
272 | struct cpuidle_device *dev; | |
273 | ||
274 | pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device); | |
275 | if (pseries_cpuidle_devices == NULL) | |
276 | return -ENOMEM; | |
277 | ||
278 | for_each_possible_cpu(i) { | |
279 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
280 | dev->state_count = drv->state_count; | |
281 | dev->cpu = i; | |
282 | if (cpuidle_register_device(dev)) { | |
283 | printk(KERN_DEBUG \ | |
284 | "cpuidle_register_device %d failed!\n", i); | |
285 | return -EIO; | |
286 | } | |
287 | } | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
707827f3 DD |
292 | /* |
293 | * pseries_idle_probe() | |
294 | * Choose state table for shared versus dedicated partition | |
295 | */ | |
296 | static int pseries_idle_probe(void) | |
297 | { | |
298 | ||
299 | if (!firmware_has_feature(FW_FEATURE_SPLPAR)) | |
300 | return -ENODEV; | |
301 | ||
e8bb3e00 DD |
302 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
303 | return -ENODEV; | |
304 | ||
707827f3 DD |
305 | if (max_idle_state == 0) { |
306 | printk(KERN_DEBUG "pseries processor idle disabled.\n"); | |
307 | return -EPERM; | |
308 | } | |
309 | ||
f13c13a0 | 310 | if (lppaca_shared_proc(get_lppaca())) |
707827f3 DD |
311 | cpuidle_state_table = shared_states; |
312 | else | |
313 | cpuidle_state_table = dedicated_states; | |
314 | ||
315 | return 0; | |
316 | } | |
317 | ||
318 | static int __init pseries_processor_idle_init(void) | |
319 | { | |
320 | int retval; | |
321 | ||
322 | retval = pseries_idle_probe(); | |
323 | if (retval) | |
324 | return retval; | |
325 | ||
326 | pseries_cpuidle_driver_init(); | |
962e7bd4 | 327 | retval = cpuidle_register_driver(&pseries_idle_driver); |
707827f3 DD |
328 | if (retval) { |
329 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
330 | return retval; | |
331 | } | |
332 | ||
962e7bd4 DD |
333 | retval = pseries_idle_devices_init(); |
334 | if (retval) { | |
335 | pseries_idle_devices_uninit(); | |
336 | cpuidle_unregister_driver(&pseries_idle_driver); | |
337 | return retval; | |
338 | } | |
339 | ||
16aaaff6 | 340 | register_cpu_notifier(&setup_hotplug_notifier); |
707827f3 DD |
341 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | static void __exit pseries_processor_idle_exit(void) | |
347 | { | |
348 | ||
852d8cb1 | 349 | unregister_cpu_notifier(&setup_hotplug_notifier); |
962e7bd4 DD |
350 | pseries_idle_devices_uninit(); |
351 | cpuidle_unregister_driver(&pseries_idle_driver); | |
707827f3 DD |
352 | |
353 | return; | |
354 | } | |
355 | ||
356 | module_init(pseries_processor_idle_init); | |
357 | module_exit(pseries_processor_idle_exit); | |
358 | ||
359 | MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>"); | |
360 | MODULE_DESCRIPTION("Cpuidle driver for POWER"); | |
361 | MODULE_LICENSE("GPL"); |