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; | |
707827f3 DD |
30 | static struct cpuidle_state *cpuidle_state_table; |
31 | ||
1ca80944 | 32 | static inline void idle_loop_prolog(unsigned long *in_purr) |
707827f3 | 33 | { |
707827f3 DD |
34 | *in_purr = mfspr(SPRN_PURR); |
35 | /* | |
36 | * Indicate to the HV that we are idle. Now would be | |
37 | * a good time to find other work to dispatch. | |
38 | */ | |
39 | get_lppaca()->idle = 1; | |
40 | } | |
41 | ||
1ca80944 | 42 | static inline void idle_loop_epilog(unsigned long in_purr) |
707827f3 | 43 | { |
7ffcf8ec AB |
44 | u64 wait_cycles; |
45 | ||
46 | wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles); | |
47 | wait_cycles += mfspr(SPRN_PURR) - in_purr; | |
48 | get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); | |
707827f3 | 49 | get_lppaca()->idle = 0; |
707827f3 DD |
50 | } |
51 | ||
52 | static int snooze_loop(struct cpuidle_device *dev, | |
53 | struct cpuidle_driver *drv, | |
54 | int index) | |
55 | { | |
56 | unsigned long in_purr; | |
707827f3 | 57 | |
1ca80944 | 58 | idle_loop_prolog(&in_purr); |
83dac594 DD |
59 | local_irq_enable(); |
60 | set_thread_flag(TIF_POLLING_NRFLAG); | |
707827f3 | 61 | |
b69dbba0 | 62 | while (!need_resched()) { |
83dac594 DD |
63 | HMT_low(); |
64 | HMT_very_low(); | |
707827f3 DD |
65 | } |
66 | ||
707827f3 | 67 | HMT_medium(); |
83dac594 DD |
68 | clear_thread_flag(TIF_POLLING_NRFLAG); |
69 | smp_mb(); | |
70 | ||
1ca80944 DL |
71 | idle_loop_epilog(in_purr); |
72 | ||
707827f3 DD |
73 | return index; |
74 | } | |
75 | ||
7230c564 BH |
76 | static void check_and_cede_processor(void) |
77 | { | |
78 | /* | |
be2cf20a BH |
79 | * Ensure our interrupt state is properly tracked, |
80 | * also checks if no interrupt has occurred while we | |
81 | * were soft-disabled | |
7230c564 | 82 | */ |
be2cf20a | 83 | if (prep_irq_for_idle()) { |
7230c564 | 84 | cede_processor(); |
be2cf20a BH |
85 | #ifdef CONFIG_TRACE_IRQFLAGS |
86 | /* Ensure that H_CEDE returns with IRQs on */ | |
87 | if (WARN_ON(!(mfmsr() & MSR_EE))) | |
88 | __hard_irq_enable(); | |
89 | #endif | |
90 | } | |
7230c564 BH |
91 | } |
92 | ||
707827f3 DD |
93 | static int dedicated_cede_loop(struct cpuidle_device *dev, |
94 | struct cpuidle_driver *drv, | |
95 | int index) | |
96 | { | |
97 | unsigned long in_purr; | |
707827f3 | 98 | |
1ca80944 | 99 | idle_loop_prolog(&in_purr); |
707827f3 DD |
100 | get_lppaca()->donate_dedicated_cpu = 1; |
101 | ||
707827f3 | 102 | HMT_medium(); |
7230c564 | 103 | check_and_cede_processor(); |
707827f3 DD |
104 | |
105 | get_lppaca()->donate_dedicated_cpu = 0; | |
1ca80944 DL |
106 | |
107 | idle_loop_epilog(in_purr); | |
108 | ||
707827f3 DD |
109 | return index; |
110 | } | |
111 | ||
112 | static int shared_cede_loop(struct cpuidle_device *dev, | |
113 | struct cpuidle_driver *drv, | |
114 | int index) | |
115 | { | |
116 | unsigned long in_purr; | |
707827f3 | 117 | |
1ca80944 | 118 | idle_loop_prolog(&in_purr); |
707827f3 DD |
119 | |
120 | /* | |
121 | * Yield the processor to the hypervisor. We return if | |
122 | * an external interrupt occurs (which are driven prior | |
123 | * to returning here) or if a prod occurs from another | |
124 | * processor. When returning here, external interrupts | |
125 | * are enabled. | |
126 | */ | |
7230c564 | 127 | check_and_cede_processor(); |
707827f3 | 128 | |
1ca80944 DL |
129 | idle_loop_epilog(in_purr); |
130 | ||
707827f3 DD |
131 | return index; |
132 | } | |
133 | ||
134 | /* | |
135 | * States for dedicated partition case. | |
136 | */ | |
137 | static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = { | |
138 | { /* Snooze */ | |
139 | .name = "snooze", | |
140 | .desc = "snooze", | |
141 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
142 | .exit_latency = 0, | |
143 | .target_residency = 0, | |
144 | .enter = &snooze_loop }, | |
145 | { /* CEDE */ | |
146 | .name = "CEDE", | |
147 | .desc = "CEDE", | |
148 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
83dac594 DD |
149 | .exit_latency = 10, |
150 | .target_residency = 100, | |
707827f3 DD |
151 | .enter = &dedicated_cede_loop }, |
152 | }; | |
153 | ||
154 | /* | |
155 | * States for shared partition case. | |
156 | */ | |
157 | static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { | |
158 | { /* Shared Cede */ | |
159 | .name = "Shared Cede", | |
160 | .desc = "Shared Cede", | |
161 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
162 | .exit_latency = 0, | |
163 | .target_residency = 0, | |
164 | .enter = &shared_cede_loop }, | |
165 | }; | |
166 | ||
8ea959a1 DD |
167 | void update_smt_snooze_delay(int cpu, int residency) |
168 | { | |
169 | struct cpuidle_driver *drv = cpuidle_get_driver(); | |
170 | struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); | |
171 | ||
172 | if (cpuidle_state_table != dedicated_states) | |
173 | return; | |
174 | ||
175 | if (residency < 0) { | |
176 | /* Disable the Nap state on that cpu */ | |
177 | if (dev) | |
178 | dev->states_usage[1].disable = 1; | |
179 | } else | |
180 | if (drv) | |
83dac594 | 181 | drv->states[1].target_residency = residency; |
8ea959a1 DD |
182 | } |
183 | ||
16aaaff6 DD |
184 | static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, |
185 | unsigned long action, void *hcpu) | |
707827f3 | 186 | { |
16aaaff6 | 187 | int hotcpu = (unsigned long)hcpu; |
707827f3 | 188 | struct cpuidle_device *dev = |
b69dbba0 | 189 | per_cpu(cpuidle_devices, hotcpu); |
16aaaff6 | 190 | |
852d8cb1 DD |
191 | if (dev && cpuidle_get_driver()) { |
192 | switch (action) { | |
193 | case CPU_ONLINE: | |
194 | case CPU_ONLINE_FROZEN: | |
195 | cpuidle_pause_and_lock(); | |
16aaaff6 | 196 | cpuidle_enable_device(dev); |
852d8cb1 DD |
197 | cpuidle_resume_and_unlock(); |
198 | break; | |
199 | ||
200 | case CPU_DEAD: | |
201 | case CPU_DEAD_FROZEN: | |
202 | cpuidle_pause_and_lock(); | |
203 | cpuidle_disable_device(dev); | |
204 | cpuidle_resume_and_unlock(); | |
205 | break; | |
206 | ||
207 | default: | |
208 | return NOTIFY_DONE; | |
16aaaff6 | 209 | } |
707827f3 | 210 | } |
16aaaff6 | 211 | return NOTIFY_OK; |
707827f3 DD |
212 | } |
213 | ||
16aaaff6 DD |
214 | static struct notifier_block setup_hotplug_notifier = { |
215 | .notifier_call = pseries_cpuidle_add_cpu_notifier, | |
216 | }; | |
217 | ||
707827f3 DD |
218 | /* |
219 | * pseries_cpuidle_driver_init() | |
220 | */ | |
221 | static int pseries_cpuidle_driver_init(void) | |
222 | { | |
223 | int idle_state; | |
224 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
225 | ||
226 | drv->state_count = 0; | |
227 | ||
228 | for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { | |
229 | ||
230 | if (idle_state > max_idle_state) | |
231 | break; | |
232 | ||
233 | /* is the state not enabled? */ | |
234 | if (cpuidle_state_table[idle_state].enter == NULL) | |
235 | continue; | |
236 | ||
237 | drv->states[drv->state_count] = /* structure copy */ | |
238 | cpuidle_state_table[idle_state]; | |
239 | ||
707827f3 DD |
240 | drv->state_count += 1; |
241 | } | |
242 | ||
243 | return 0; | |
244 | } | |
245 | ||
707827f3 DD |
246 | /* |
247 | * pseries_idle_probe() | |
248 | * Choose state table for shared versus dedicated partition | |
249 | */ | |
250 | static int pseries_idle_probe(void) | |
251 | { | |
252 | ||
e8bb3e00 DD |
253 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
254 | return -ENODEV; | |
255 | ||
707827f3 DD |
256 | if (max_idle_state == 0) { |
257 | printk(KERN_DEBUG "pseries processor idle disabled.\n"); | |
258 | return -EPERM; | |
259 | } | |
260 | ||
b69dbba0 DD |
261 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
262 | if (lppaca_shared_proc(get_lppaca())) | |
263 | cpuidle_state_table = shared_states; | |
264 | else | |
265 | cpuidle_state_table = dedicated_states; | |
266 | } else | |
267 | return -ENODEV; | |
707827f3 DD |
268 | |
269 | return 0; | |
270 | } | |
271 | ||
272 | static int __init pseries_processor_idle_init(void) | |
273 | { | |
274 | int retval; | |
275 | ||
276 | retval = pseries_idle_probe(); | |
277 | if (retval) | |
278 | return retval; | |
279 | ||
280 | pseries_cpuidle_driver_init(); | |
b69dbba0 | 281 | retval = cpuidle_register(&pseries_idle_driver, NULL); |
707827f3 DD |
282 | if (retval) { |
283 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
284 | return retval; | |
285 | } | |
286 | ||
16aaaff6 | 287 | register_cpu_notifier(&setup_hotplug_notifier); |
707827f3 | 288 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
707827f3 DD |
289 | return 0; |
290 | } | |
291 | ||
292 | static void __exit pseries_processor_idle_exit(void) | |
293 | { | |
294 | ||
852d8cb1 | 295 | unregister_cpu_notifier(&setup_hotplug_notifier); |
b69dbba0 | 296 | cpuidle_unregister(&pseries_idle_driver); |
707827f3 DD |
297 | return; |
298 | } | |
299 | ||
300 | module_init(pseries_processor_idle_init); | |
301 | module_exit(pseries_processor_idle_exit); | |
302 | ||
303 | MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>"); | |
304 | MODULE_DESCRIPTION("Cpuidle driver for POWER"); | |
305 | MODULE_LICENSE("GPL"); |