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> | |
14 | ||
15 | #include <asm/paca.h> | |
16 | #include <asm/reg.h> | |
707827f3 DD |
17 | #include <asm/machdep.h> |
18 | #include <asm/firmware.h> | |
ae3a197e | 19 | #include <asm/runlatch.h> |
707827f3 DD |
20 | |
21 | #include "plpar_wrappers.h" | |
22 | #include "pseries.h" | |
23 | ||
24 | struct cpuidle_driver pseries_idle_driver = { | |
25 | .name = "pseries_idle", | |
26 | .owner = THIS_MODULE, | |
27 | }; | |
28 | ||
29 | #define MAX_IDLE_STATE_COUNT 2 | |
30 | ||
31 | static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; | |
32 | static struct cpuidle_device __percpu *pseries_cpuidle_devices; | |
33 | static struct cpuidle_state *cpuidle_state_table; | |
34 | ||
35 | void update_smt_snooze_delay(int snooze) | |
36 | { | |
37 | struct cpuidle_driver *drv = cpuidle_get_driver(); | |
38 | if (drv) | |
39 | drv->states[0].target_residency = snooze; | |
40 | } | |
41 | ||
42 | static inline void idle_loop_prolog(unsigned long *in_purr, ktime_t *kt_before) | |
43 | { | |
44 | ||
45 | *kt_before = ktime_get_real(); | |
46 | *in_purr = mfspr(SPRN_PURR); | |
47 | /* | |
48 | * Indicate to the HV that we are idle. Now would be | |
49 | * a good time to find other work to dispatch. | |
50 | */ | |
51 | get_lppaca()->idle = 1; | |
52 | } | |
53 | ||
54 | static inline s64 idle_loop_epilog(unsigned long in_purr, ktime_t kt_before) | |
55 | { | |
56 | get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr; | |
57 | get_lppaca()->idle = 0; | |
58 | ||
59 | return ktime_to_us(ktime_sub(ktime_get_real(), kt_before)); | |
60 | } | |
61 | ||
62 | static int snooze_loop(struct cpuidle_device *dev, | |
63 | struct cpuidle_driver *drv, | |
64 | int index) | |
65 | { | |
66 | unsigned long in_purr; | |
67 | ktime_t kt_before; | |
68 | unsigned long start_snooze; | |
69 | long snooze = drv->states[0].target_residency; | |
70 | ||
71 | idle_loop_prolog(&in_purr, &kt_before); | |
72 | ||
73 | if (snooze) { | |
74 | start_snooze = get_tb() + snooze * tb_ticks_per_usec; | |
75 | local_irq_enable(); | |
76 | set_thread_flag(TIF_POLLING_NRFLAG); | |
77 | ||
78 | while ((snooze < 0) || (get_tb() < start_snooze)) { | |
79 | if (need_resched() || cpu_is_offline(dev->cpu)) | |
80 | goto out; | |
81 | ppc64_runlatch_off(); | |
82 | HMT_low(); | |
83 | HMT_very_low(); | |
84 | } | |
85 | ||
86 | HMT_medium(); | |
87 | clear_thread_flag(TIF_POLLING_NRFLAG); | |
88 | smp_mb(); | |
89 | local_irq_disable(); | |
90 | } | |
91 | ||
92 | out: | |
93 | HMT_medium(); | |
94 | dev->last_residency = | |
95 | (int)idle_loop_epilog(in_purr, kt_before); | |
96 | return index; | |
97 | } | |
98 | ||
7230c564 BH |
99 | static void check_and_cede_processor(void) |
100 | { | |
101 | /* | |
102 | * Interrupts are soft-disabled at this point, | |
103 | * but not hard disabled. So an interrupt might have | |
104 | * occurred before entering NAP, and would be potentially | |
105 | * lost (edge events, decrementer events, etc...) unless | |
106 | * we first hard disable then check. | |
107 | */ | |
108 | hard_irq_disable(); | |
0b17ba72 | 109 | if (!lazy_irq_pending()) |
7230c564 BH |
110 | cede_processor(); |
111 | } | |
112 | ||
707827f3 DD |
113 | static int dedicated_cede_loop(struct cpuidle_device *dev, |
114 | struct cpuidle_driver *drv, | |
115 | int index) | |
116 | { | |
117 | unsigned long in_purr; | |
118 | ktime_t kt_before; | |
119 | ||
120 | idle_loop_prolog(&in_purr, &kt_before); | |
121 | get_lppaca()->donate_dedicated_cpu = 1; | |
122 | ||
123 | ppc64_runlatch_off(); | |
124 | HMT_medium(); | |
7230c564 | 125 | check_and_cede_processor(); |
707827f3 DD |
126 | |
127 | get_lppaca()->donate_dedicated_cpu = 0; | |
128 | dev->last_residency = | |
129 | (int)idle_loop_epilog(in_purr, kt_before); | |
130 | return index; | |
131 | } | |
132 | ||
133 | static int shared_cede_loop(struct cpuidle_device *dev, | |
134 | struct cpuidle_driver *drv, | |
135 | int index) | |
136 | { | |
137 | unsigned long in_purr; | |
138 | ktime_t kt_before; | |
139 | ||
140 | idle_loop_prolog(&in_purr, &kt_before); | |
141 | ||
142 | /* | |
143 | * Yield the processor to the hypervisor. We return if | |
144 | * an external interrupt occurs (which are driven prior | |
145 | * to returning here) or if a prod occurs from another | |
146 | * processor. When returning here, external interrupts | |
147 | * are enabled. | |
148 | */ | |
7230c564 | 149 | check_and_cede_processor(); |
707827f3 DD |
150 | |
151 | dev->last_residency = | |
152 | (int)idle_loop_epilog(in_purr, kt_before); | |
153 | return index; | |
154 | } | |
155 | ||
156 | /* | |
157 | * States for dedicated partition case. | |
158 | */ | |
159 | static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { | |
160 | { /* Snooze */ | |
161 | .name = "snooze", | |
162 | .desc = "snooze", | |
163 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
164 | .exit_latency = 0, | |
165 | .target_residency = 0, | |
166 | .enter = &snooze_loop }, | |
167 | { /* CEDE */ | |
168 | .name = "CEDE", | |
169 | .desc = "CEDE", | |
170 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
171 | .exit_latency = 1, | |
172 | .target_residency = 10, | |
173 | .enter = &dedicated_cede_loop }, | |
174 | }; | |
175 | ||
176 | /* | |
177 | * States for shared partition case. | |
178 | */ | |
179 | static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { | |
180 | { /* Shared Cede */ | |
181 | .name = "Shared Cede", | |
182 | .desc = "Shared Cede", | |
183 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
184 | .exit_latency = 0, | |
185 | .target_residency = 0, | |
186 | .enter = &shared_cede_loop }, | |
187 | }; | |
188 | ||
189 | int pseries_notify_cpuidle_add_cpu(int cpu) | |
190 | { | |
191 | struct cpuidle_device *dev = | |
192 | per_cpu_ptr(pseries_cpuidle_devices, cpu); | |
193 | if (dev && cpuidle_get_driver()) { | |
194 | cpuidle_disable_device(dev); | |
195 | cpuidle_enable_device(dev); | |
196 | } | |
197 | return 0; | |
198 | } | |
199 | ||
200 | /* | |
201 | * pseries_cpuidle_driver_init() | |
202 | */ | |
203 | static int pseries_cpuidle_driver_init(void) | |
204 | { | |
205 | int idle_state; | |
206 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
207 | ||
208 | drv->state_count = 0; | |
209 | ||
210 | for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { | |
211 | ||
212 | if (idle_state > max_idle_state) | |
213 | break; | |
214 | ||
215 | /* is the state not enabled? */ | |
216 | if (cpuidle_state_table[idle_state].enter == NULL) | |
217 | continue; | |
218 | ||
219 | drv->states[drv->state_count] = /* structure copy */ | |
220 | cpuidle_state_table[idle_state]; | |
221 | ||
222 | if (cpuidle_state_table == dedicated_states) | |
223 | drv->states[drv->state_count].target_residency = | |
224 | __get_cpu_var(smt_snooze_delay); | |
225 | ||
226 | drv->state_count += 1; | |
227 | } | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
232 | /* pseries_idle_devices_uninit(void) | |
233 | * unregister cpuidle devices and de-allocate memory | |
234 | */ | |
235 | static void pseries_idle_devices_uninit(void) | |
236 | { | |
237 | int i; | |
238 | struct cpuidle_device *dev; | |
239 | ||
240 | for_each_possible_cpu(i) { | |
241 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
242 | cpuidle_unregister_device(dev); | |
243 | } | |
244 | ||
245 | free_percpu(pseries_cpuidle_devices); | |
246 | return; | |
247 | } | |
248 | ||
249 | /* pseries_idle_devices_init() | |
250 | * allocate, initialize and register cpuidle device | |
251 | */ | |
252 | static int pseries_idle_devices_init(void) | |
253 | { | |
254 | int i; | |
255 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
256 | struct cpuidle_device *dev; | |
257 | ||
258 | pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device); | |
259 | if (pseries_cpuidle_devices == NULL) | |
260 | return -ENOMEM; | |
261 | ||
262 | for_each_possible_cpu(i) { | |
263 | dev = per_cpu_ptr(pseries_cpuidle_devices, i); | |
264 | dev->state_count = drv->state_count; | |
265 | dev->cpu = i; | |
266 | if (cpuidle_register_device(dev)) { | |
267 | printk(KERN_DEBUG \ | |
268 | "cpuidle_register_device %d failed!\n", i); | |
269 | return -EIO; | |
270 | } | |
271 | } | |
272 | ||
273 | return 0; | |
274 | } | |
275 | ||
276 | /* | |
277 | * pseries_idle_probe() | |
278 | * Choose state table for shared versus dedicated partition | |
279 | */ | |
280 | static int pseries_idle_probe(void) | |
281 | { | |
282 | ||
283 | if (!firmware_has_feature(FW_FEATURE_SPLPAR)) | |
284 | return -ENODEV; | |
285 | ||
e8bb3e00 DD |
286 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
287 | return -ENODEV; | |
288 | ||
707827f3 DD |
289 | if (max_idle_state == 0) { |
290 | printk(KERN_DEBUG "pseries processor idle disabled.\n"); | |
291 | return -EPERM; | |
292 | } | |
293 | ||
294 | if (get_lppaca()->shared_proc) | |
295 | cpuidle_state_table = shared_states; | |
296 | else | |
297 | cpuidle_state_table = dedicated_states; | |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
302 | static int __init pseries_processor_idle_init(void) | |
303 | { | |
304 | int retval; | |
305 | ||
306 | retval = pseries_idle_probe(); | |
307 | if (retval) | |
308 | return retval; | |
309 | ||
310 | pseries_cpuidle_driver_init(); | |
311 | retval = cpuidle_register_driver(&pseries_idle_driver); | |
312 | if (retval) { | |
313 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
314 | return retval; | |
315 | } | |
316 | ||
317 | retval = pseries_idle_devices_init(); | |
318 | if (retval) { | |
319 | pseries_idle_devices_uninit(); | |
320 | cpuidle_unregister_driver(&pseries_idle_driver); | |
321 | return retval; | |
322 | } | |
323 | ||
324 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); | |
325 | ||
326 | return 0; | |
327 | } | |
328 | ||
329 | static void __exit pseries_processor_idle_exit(void) | |
330 | { | |
331 | ||
332 | pseries_idle_devices_uninit(); | |
333 | cpuidle_unregister_driver(&pseries_idle_driver); | |
334 | ||
335 | return; | |
336 | } | |
337 | ||
338 | module_init(pseries_processor_idle_init); | |
339 | module_exit(pseries_processor_idle_exit); | |
340 | ||
341 | MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>"); | |
342 | MODULE_DESCRIPTION("Cpuidle driver for POWER"); | |
343 | MODULE_LICENSE("GPL"); |