Commit | Line | Data |
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707827f3 DD |
1 | /* |
2 | * processor_idle - idle state cpuidle driver. | |
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> | |
ae3a197e | 20 | #include <asm/runlatch.h> |
707827f3 DD |
21 | |
22 | #include "plpar_wrappers.h" | |
23 | #include "pseries.h" | |
24 | ||
25 | struct cpuidle_driver pseries_idle_driver = { | |
26 | .name = "pseries_idle", | |
27 | .owner = THIS_MODULE, | |
28 | }; | |
29 | ||
30 | #define MAX_IDLE_STATE_COUNT 2 | |
31 | ||
32 | static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; | |
33 | static struct cpuidle_device __percpu *pseries_cpuidle_devices; | |
34 | static struct cpuidle_state *cpuidle_state_table; | |
35 | ||
36 | void update_smt_snooze_delay(int snooze) | |
37 | { | |
38 | struct cpuidle_driver *drv = cpuidle_get_driver(); | |
39 | if (drv) | |
40 | drv->states[0].target_residency = snooze; | |
41 | } | |
42 | ||
43 | static inline void idle_loop_prolog(unsigned long *in_purr, ktime_t *kt_before) | |
44 | { | |
45 | ||
46 | *kt_before = ktime_get_real(); | |
47 | *in_purr = mfspr(SPRN_PURR); | |
48 | /* | |
49 | * Indicate to the HV that we are idle. Now would be | |
50 | * a good time to find other work to dispatch. | |
51 | */ | |
52 | get_lppaca()->idle = 1; | |
53 | } | |
54 | ||
55 | static inline s64 idle_loop_epilog(unsigned long in_purr, ktime_t kt_before) | |
56 | { | |
57 | get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr; | |
58 | get_lppaca()->idle = 0; | |
59 | ||
60 | return ktime_to_us(ktime_sub(ktime_get_real(), kt_before)); | |
61 | } | |
62 | ||
63 | static int snooze_loop(struct cpuidle_device *dev, | |
64 | struct cpuidle_driver *drv, | |
65 | int index) | |
66 | { | |
67 | unsigned long in_purr; | |
68 | ktime_t kt_before; | |
69 | unsigned long start_snooze; | |
70 | long snooze = drv->states[0].target_residency; | |
71 | ||
72 | idle_loop_prolog(&in_purr, &kt_before); | |
73 | ||
74 | if (snooze) { | |
75 | start_snooze = get_tb() + snooze * tb_ticks_per_usec; | |
76 | local_irq_enable(); | |
77 | set_thread_flag(TIF_POLLING_NRFLAG); | |
78 | ||
79 | while ((snooze < 0) || (get_tb() < start_snooze)) { | |
80 | if (need_resched() || cpu_is_offline(dev->cpu)) | |
81 | goto out; | |
82 | ppc64_runlatch_off(); | |
83 | HMT_low(); | |
84 | HMT_very_low(); | |
85 | } | |
86 | ||
87 | HMT_medium(); | |
88 | clear_thread_flag(TIF_POLLING_NRFLAG); | |
89 | smp_mb(); | |
90 | local_irq_disable(); | |
91 | } | |
92 | ||
93 | out: | |
94 | HMT_medium(); | |
95 | dev->last_residency = | |
96 | (int)idle_loop_epilog(in_purr, kt_before); | |
97 | return index; | |
98 | } | |
99 | ||
7230c564 BH |
100 | static void check_and_cede_processor(void) |
101 | { | |
102 | /* | |
be2cf20a BH |
103 | * Ensure our interrupt state is properly tracked, |
104 | * also checks if no interrupt has occurred while we | |
105 | * were soft-disabled | |
7230c564 | 106 | */ |
be2cf20a | 107 | if (prep_irq_for_idle()) { |
7230c564 | 108 | cede_processor(); |
be2cf20a BH |
109 | #ifdef CONFIG_TRACE_IRQFLAGS |
110 | /* Ensure that H_CEDE returns with IRQs on */ | |
111 | if (WARN_ON(!(mfmsr() & MSR_EE))) | |
112 | __hard_irq_enable(); | |
113 | #endif | |
114 | } | |
7230c564 BH |
115 | } |
116 | ||
707827f3 DD |
117 | static int dedicated_cede_loop(struct cpuidle_device *dev, |
118 | struct cpuidle_driver *drv, | |
119 | int index) | |
120 | { | |
121 | unsigned long in_purr; | |
122 | ktime_t kt_before; | |
123 | ||
124 | idle_loop_prolog(&in_purr, &kt_before); | |
125 | get_lppaca()->donate_dedicated_cpu = 1; | |
126 | ||
127 | ppc64_runlatch_off(); | |
128 | HMT_medium(); | |
7230c564 | 129 | check_and_cede_processor(); |
707827f3 DD |
130 | |
131 | get_lppaca()->donate_dedicated_cpu = 0; | |
132 | dev->last_residency = | |
133 | (int)idle_loop_epilog(in_purr, kt_before); | |
134 | return index; | |
135 | } | |
136 | ||
137 | static int shared_cede_loop(struct cpuidle_device *dev, | |
138 | struct cpuidle_driver *drv, | |
139 | int index) | |
140 | { | |
141 | unsigned long in_purr; | |
142 | ktime_t kt_before; | |
143 | ||
144 | idle_loop_prolog(&in_purr, &kt_before); | |
145 | ||
146 | /* | |
147 | * Yield the processor to the hypervisor. We return if | |
148 | * an external interrupt occurs (which are driven prior | |
149 | * to returning here) or if a prod occurs from another | |
150 | * processor. When returning here, external interrupts | |
151 | * are enabled. | |
152 | */ | |
7230c564 | 153 | check_and_cede_processor(); |
707827f3 DD |
154 | |
155 | dev->last_residency = | |
156 | (int)idle_loop_epilog(in_purr, kt_before); | |
157 | return index; | |
158 | } | |
159 | ||
160 | /* | |
161 | * States for dedicated partition case. | |
162 | */ | |
163 | static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { | |
164 | { /* Snooze */ | |
165 | .name = "snooze", | |
166 | .desc = "snooze", | |
167 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
168 | .exit_latency = 0, | |
169 | .target_residency = 0, | |
170 | .enter = &snooze_loop }, | |
171 | { /* CEDE */ | |
172 | .name = "CEDE", | |
173 | .desc = "CEDE", | |
174 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
175 | .exit_latency = 1, | |
176 | .target_residency = 10, | |
177 | .enter = &dedicated_cede_loop }, | |
178 | }; | |
179 | ||
180 | /* | |
181 | * States for shared partition case. | |
182 | */ | |
183 | static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { | |
184 | { /* Shared Cede */ | |
185 | .name = "Shared Cede", | |
186 | .desc = "Shared Cede", | |
187 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
188 | .exit_latency = 0, | |
189 | .target_residency = 0, | |
190 | .enter = &shared_cede_loop }, | |
191 | }; | |
192 | ||
16aaaff6 DD |
193 | static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, |
194 | unsigned long action, void *hcpu) | |
707827f3 | 195 | { |
16aaaff6 | 196 | int hotcpu = (unsigned long)hcpu; |
707827f3 | 197 | struct cpuidle_device *dev = |
16aaaff6 DD |
198 | per_cpu_ptr(pseries_cpuidle_devices, hotcpu); |
199 | ||
200 | switch (action & 0xf) { | |
201 | case CPU_ONLINE: | |
202 | if (dev && cpuidle_get_driver()) { | |
203 | cpuidle_disable_device(dev); | |
204 | cpuidle_enable_device(dev); | |
205 | } | |
206 | break; | |
707827f3 | 207 | } |
16aaaff6 | 208 | return NOTIFY_OK; |
707827f3 DD |
209 | } |
210 | ||
16aaaff6 DD |
211 | static struct notifier_block setup_hotplug_notifier = { |
212 | .notifier_call = pseries_cpuidle_add_cpu_notifier, | |
213 | }; | |
214 | ||
707827f3 DD |
215 | /* |
216 | * pseries_cpuidle_driver_init() | |
217 | */ | |
218 | static int pseries_cpuidle_driver_init(void) | |
219 | { | |
220 | int idle_state; | |
221 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
222 | ||
223 | drv->state_count = 0; | |
224 | ||
225 | for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { | |
226 | ||
227 | if (idle_state > max_idle_state) | |
228 | break; | |
229 | ||
230 | /* is the state not enabled? */ | |
231 | if (cpuidle_state_table[idle_state].enter == NULL) | |
232 | continue; | |
233 | ||
234 | drv->states[drv->state_count] = /* structure copy */ | |
235 | cpuidle_state_table[idle_state]; | |
236 | ||
237 | if (cpuidle_state_table == dedicated_states) | |
238 | drv->states[drv->state_count].target_residency = | |
239 | __get_cpu_var(smt_snooze_delay); | |
240 | ||
241 | drv->state_count += 1; | |
242 | } | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
247 | /* pseries_idle_devices_uninit(void) | |
248 | * unregister cpuidle devices and de-allocate memory | |
249 | */ | |
250 | static void pseries_idle_devices_uninit(void) | |
251 | { | |
252 | int i; | |
253 | struct cpuidle_device *dev; | |
254 | ||
255 | for_each_possible_cpu(i) { | |
256 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
257 | cpuidle_unregister_device(dev); | |
258 | } | |
259 | ||
260 | free_percpu(pseries_cpuidle_devices); | |
261 | return; | |
262 | } | |
263 | ||
264 | /* pseries_idle_devices_init() | |
265 | * allocate, initialize and register cpuidle device | |
266 | */ | |
267 | static int pseries_idle_devices_init(void) | |
268 | { | |
269 | int i; | |
270 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
271 | struct cpuidle_device *dev; | |
272 | ||
273 | pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device); | |
274 | if (pseries_cpuidle_devices == NULL) | |
275 | return -ENOMEM; | |
276 | ||
277 | for_each_possible_cpu(i) { | |
278 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
279 | dev->state_count = drv->state_count; | |
280 | dev->cpu = i; | |
281 | if (cpuidle_register_device(dev)) { | |
282 | printk(KERN_DEBUG \ | |
283 | "cpuidle_register_device %d failed!\n", i); | |
284 | return -EIO; | |
285 | } | |
286 | } | |
287 | ||
288 | return 0; | |
289 | } | |
290 | ||
291 | /* | |
292 | * pseries_idle_probe() | |
293 | * Choose state table for shared versus dedicated partition | |
294 | */ | |
295 | static int pseries_idle_probe(void) | |
296 | { | |
297 | ||
298 | if (!firmware_has_feature(FW_FEATURE_SPLPAR)) | |
299 | return -ENODEV; | |
300 | ||
e8bb3e00 DD |
301 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
302 | return -ENODEV; | |
303 | ||
707827f3 DD |
304 | if (max_idle_state == 0) { |
305 | printk(KERN_DEBUG "pseries processor idle disabled.\n"); | |
306 | return -EPERM; | |
307 | } | |
308 | ||
309 | if (get_lppaca()->shared_proc) | |
310 | cpuidle_state_table = shared_states; | |
311 | else | |
312 | cpuidle_state_table = dedicated_states; | |
313 | ||
314 | return 0; | |
315 | } | |
316 | ||
317 | static int __init pseries_processor_idle_init(void) | |
318 | { | |
319 | int retval; | |
320 | ||
321 | retval = pseries_idle_probe(); | |
322 | if (retval) | |
323 | return retval; | |
324 | ||
325 | pseries_cpuidle_driver_init(); | |
326 | retval = cpuidle_register_driver(&pseries_idle_driver); | |
327 | if (retval) { | |
328 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
329 | return retval; | |
330 | } | |
331 | ||
332 | retval = pseries_idle_devices_init(); | |
333 | if (retval) { | |
334 | pseries_idle_devices_uninit(); | |
335 | cpuidle_unregister_driver(&pseries_idle_driver); | |
336 | return retval; | |
337 | } | |
338 | ||
16aaaff6 | 339 | register_cpu_notifier(&setup_hotplug_notifier); |
707827f3 DD |
340 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
341 | ||
342 | return 0; | |
343 | } | |
344 | ||
345 | static void __exit pseries_processor_idle_exit(void) | |
346 | { | |
347 | ||
348 | pseries_idle_devices_uninit(); | |
349 | cpuidle_unregister_driver(&pseries_idle_driver); | |
350 | ||
351 | return; | |
352 | } | |
353 | ||
354 | module_init(pseries_processor_idle_init); | |
355 | module_exit(pseries_processor_idle_exit); | |
356 | ||
357 | MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>"); | |
358 | MODULE_DESCRIPTION("Cpuidle driver for POWER"); | |
359 | MODULE_LICENSE("GPL"); |