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> | |
3f67d962 | 20 | #include <asm/runlatch.h> |
212bebb4 | 21 | #include <asm/plpar_wrappers.h> |
707827f3 DD |
22 | |
23 | struct cpuidle_driver pseries_idle_driver = { | |
1ca80944 DL |
24 | .name = "pseries_idle", |
25 | .owner = THIS_MODULE, | |
707827f3 DD |
26 | }; |
27 | ||
bf7f61f2 | 28 | static int max_idle_state; |
707827f3 DD |
29 | static struct cpuidle_state *cpuidle_state_table; |
30 | ||
1ca80944 | 31 | static inline void idle_loop_prolog(unsigned long *in_purr) |
707827f3 | 32 | { |
d8c6ad31 | 33 | ppc64_runlatch_off(); |
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; |
d8c6ad31 NP |
50 | |
51 | if (irqs_disabled()) | |
52 | local_irq_enable(); | |
53 | ppc64_runlatch_on(); | |
707827f3 DD |
54 | } |
55 | ||
56 | static int snooze_loop(struct cpuidle_device *dev, | |
57 | struct cpuidle_driver *drv, | |
58 | int index) | |
59 | { | |
60 | unsigned long in_purr; | |
707827f3 | 61 | |
1ca80944 | 62 | idle_loop_prolog(&in_purr); |
83dac594 DD |
63 | local_irq_enable(); |
64 | set_thread_flag(TIF_POLLING_NRFLAG); | |
707827f3 | 65 | |
b69dbba0 | 66 | while (!need_resched()) { |
83dac594 DD |
67 | HMT_low(); |
68 | HMT_very_low(); | |
707827f3 DD |
69 | } |
70 | ||
707827f3 | 71 | HMT_medium(); |
83dac594 DD |
72 | clear_thread_flag(TIF_POLLING_NRFLAG); |
73 | smp_mb(); | |
74 | ||
1ca80944 DL |
75 | idle_loop_epilog(in_purr); |
76 | ||
707827f3 DD |
77 | return index; |
78 | } | |
79 | ||
7230c564 BH |
80 | static void check_and_cede_processor(void) |
81 | { | |
82 | /* | |
be2cf20a BH |
83 | * Ensure our interrupt state is properly tracked, |
84 | * also checks if no interrupt has occurred while we | |
85 | * were soft-disabled | |
7230c564 | 86 | */ |
be2cf20a | 87 | if (prep_irq_for_idle()) { |
7230c564 | 88 | cede_processor(); |
be2cf20a BH |
89 | #ifdef CONFIG_TRACE_IRQFLAGS |
90 | /* Ensure that H_CEDE returns with IRQs on */ | |
91 | if (WARN_ON(!(mfmsr() & MSR_EE))) | |
92 | __hard_irq_enable(); | |
93 | #endif | |
94 | } | |
7230c564 BH |
95 | } |
96 | ||
707827f3 DD |
97 | static int dedicated_cede_loop(struct cpuidle_device *dev, |
98 | struct cpuidle_driver *drv, | |
99 | int index) | |
100 | { | |
101 | unsigned long in_purr; | |
707827f3 | 102 | |
1ca80944 | 103 | idle_loop_prolog(&in_purr); |
707827f3 DD |
104 | get_lppaca()->donate_dedicated_cpu = 1; |
105 | ||
707827f3 | 106 | HMT_medium(); |
7230c564 | 107 | check_and_cede_processor(); |
707827f3 DD |
108 | |
109 | get_lppaca()->donate_dedicated_cpu = 0; | |
1ca80944 DL |
110 | |
111 | idle_loop_epilog(in_purr); | |
112 | ||
707827f3 DD |
113 | return index; |
114 | } | |
115 | ||
116 | static int shared_cede_loop(struct cpuidle_device *dev, | |
117 | struct cpuidle_driver *drv, | |
118 | int index) | |
119 | { | |
120 | unsigned long in_purr; | |
707827f3 | 121 | |
1ca80944 | 122 | idle_loop_prolog(&in_purr); |
707827f3 DD |
123 | |
124 | /* | |
125 | * Yield the processor to the hypervisor. We return if | |
126 | * an external interrupt occurs (which are driven prior | |
127 | * to returning here) or if a prod occurs from another | |
128 | * processor. When returning here, external interrupts | |
129 | * are enabled. | |
130 | */ | |
7230c564 | 131 | check_and_cede_processor(); |
707827f3 | 132 | |
1ca80944 DL |
133 | idle_loop_epilog(in_purr); |
134 | ||
707827f3 DD |
135 | return index; |
136 | } | |
137 | ||
138 | /* | |
139 | * States for dedicated partition case. | |
140 | */ | |
bf7f61f2 | 141 | static struct cpuidle_state dedicated_states[] = { |
707827f3 DD |
142 | { /* Snooze */ |
143 | .name = "snooze", | |
144 | .desc = "snooze", | |
145 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
146 | .exit_latency = 0, | |
147 | .target_residency = 0, | |
148 | .enter = &snooze_loop }, | |
149 | { /* CEDE */ | |
150 | .name = "CEDE", | |
151 | .desc = "CEDE", | |
152 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
83dac594 DD |
153 | .exit_latency = 10, |
154 | .target_residency = 100, | |
707827f3 DD |
155 | .enter = &dedicated_cede_loop }, |
156 | }; | |
157 | ||
158 | /* | |
159 | * States for shared partition case. | |
160 | */ | |
bf7f61f2 | 161 | static struct cpuidle_state shared_states[] = { |
707827f3 DD |
162 | { /* Shared Cede */ |
163 | .name = "Shared Cede", | |
164 | .desc = "Shared Cede", | |
165 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
166 | .exit_latency = 0, | |
167 | .target_residency = 0, | |
168 | .enter = &shared_cede_loop }, | |
169 | }; | |
170 | ||
16aaaff6 DD |
171 | static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, |
172 | unsigned long action, void *hcpu) | |
707827f3 | 173 | { |
16aaaff6 | 174 | int hotcpu = (unsigned long)hcpu; |
707827f3 | 175 | struct cpuidle_device *dev = |
b69dbba0 | 176 | per_cpu(cpuidle_devices, hotcpu); |
16aaaff6 | 177 | |
852d8cb1 DD |
178 | if (dev && cpuidle_get_driver()) { |
179 | switch (action) { | |
180 | case CPU_ONLINE: | |
181 | case CPU_ONLINE_FROZEN: | |
182 | cpuidle_pause_and_lock(); | |
16aaaff6 | 183 | cpuidle_enable_device(dev); |
852d8cb1 DD |
184 | cpuidle_resume_and_unlock(); |
185 | break; | |
186 | ||
187 | case CPU_DEAD: | |
188 | case CPU_DEAD_FROZEN: | |
189 | cpuidle_pause_and_lock(); | |
190 | cpuidle_disable_device(dev); | |
191 | cpuidle_resume_and_unlock(); | |
192 | break; | |
193 | ||
194 | default: | |
195 | return NOTIFY_DONE; | |
16aaaff6 | 196 | } |
707827f3 | 197 | } |
16aaaff6 | 198 | return NOTIFY_OK; |
707827f3 DD |
199 | } |
200 | ||
16aaaff6 DD |
201 | static struct notifier_block setup_hotplug_notifier = { |
202 | .notifier_call = pseries_cpuidle_add_cpu_notifier, | |
203 | }; | |
204 | ||
707827f3 DD |
205 | /* |
206 | * pseries_cpuidle_driver_init() | |
207 | */ | |
208 | static int pseries_cpuidle_driver_init(void) | |
209 | { | |
210 | int idle_state; | |
211 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
212 | ||
213 | drv->state_count = 0; | |
214 | ||
bf7f61f2 DD |
215 | for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { |
216 | /* Is the state not enabled? */ | |
707827f3 DD |
217 | if (cpuidle_state_table[idle_state].enter == NULL) |
218 | continue; | |
219 | ||
220 | drv->states[drv->state_count] = /* structure copy */ | |
221 | cpuidle_state_table[idle_state]; | |
222 | ||
707827f3 DD |
223 | drv->state_count += 1; |
224 | } | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
707827f3 DD |
229 | /* |
230 | * pseries_idle_probe() | |
231 | * Choose state table for shared versus dedicated partition | |
232 | */ | |
233 | static int pseries_idle_probe(void) | |
234 | { | |
235 | ||
e8bb3e00 DD |
236 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
237 | return -ENODEV; | |
238 | ||
b69dbba0 | 239 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
bf7f61f2 | 240 | if (lppaca_shared_proc(get_lppaca())) { |
b69dbba0 | 241 | cpuidle_state_table = shared_states; |
bf7f61f2 DD |
242 | max_idle_state = ARRAY_SIZE(shared_states); |
243 | } else { | |
b69dbba0 | 244 | cpuidle_state_table = dedicated_states; |
bf7f61f2 DD |
245 | max_idle_state = ARRAY_SIZE(dedicated_states); |
246 | } | |
b69dbba0 DD |
247 | } else |
248 | return -ENODEV; | |
707827f3 DD |
249 | |
250 | return 0; | |
251 | } | |
252 | ||
253 | static int __init pseries_processor_idle_init(void) | |
254 | { | |
255 | int retval; | |
256 | ||
257 | retval = pseries_idle_probe(); | |
258 | if (retval) | |
259 | return retval; | |
260 | ||
261 | pseries_cpuidle_driver_init(); | |
b69dbba0 | 262 | retval = cpuidle_register(&pseries_idle_driver, NULL); |
707827f3 DD |
263 | if (retval) { |
264 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
265 | return retval; | |
266 | } | |
267 | ||
16aaaff6 | 268 | register_cpu_notifier(&setup_hotplug_notifier); |
707827f3 | 269 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
707827f3 DD |
270 | return 0; |
271 | } | |
272 | ||
12431c64 | 273 | device_initcall(pseries_processor_idle_init); |