2 * processor_idle - idle state cpuidle driver.
3 * Adapted from drivers/idle/intel_idle.c and
4 * drivers/acpi/processor_idle.c
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>
17 #include <asm/machdep.h>
18 #include <asm/firmware.h>
19 #include <asm/runlatch.h>
21 #include "plpar_wrappers.h"
24 struct cpuidle_driver pseries_idle_driver
= {
25 .name
= "pseries_idle",
29 #define MAX_IDLE_STATE_COUNT 2
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
;
35 void update_smt_snooze_delay(int snooze
)
37 struct cpuidle_driver
*drv
= cpuidle_get_driver();
39 drv
->states
[0].target_residency
= snooze
;
42 static inline void idle_loop_prolog(unsigned long *in_purr
, ktime_t
*kt_before
)
45 *kt_before
= ktime_get_real();
46 *in_purr
= mfspr(SPRN_PURR
);
48 * Indicate to the HV that we are idle. Now would be
49 * a good time to find other work to dispatch.
51 get_lppaca()->idle
= 1;
54 static inline s64
idle_loop_epilog(unsigned long in_purr
, ktime_t kt_before
)
56 get_lppaca()->wait_state_cycles
+= mfspr(SPRN_PURR
) - in_purr
;
57 get_lppaca()->idle
= 0;
59 return ktime_to_us(ktime_sub(ktime_get_real(), kt_before
));
62 static int snooze_loop(struct cpuidle_device
*dev
,
63 struct cpuidle_driver
*drv
,
66 unsigned long in_purr
;
68 unsigned long start_snooze
;
69 long snooze
= drv
->states
[0].target_residency
;
71 idle_loop_prolog(&in_purr
, &kt_before
);
74 start_snooze
= get_tb() + snooze
* tb_ticks_per_usec
;
76 set_thread_flag(TIF_POLLING_NRFLAG
);
78 while ((snooze
< 0) || (get_tb() < start_snooze
)) {
79 if (need_resched() || cpu_is_offline(dev
->cpu
))
87 clear_thread_flag(TIF_POLLING_NRFLAG
);
95 (int)idle_loop_epilog(in_purr
, kt_before
);
99 static void check_and_cede_processor(void)
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.
109 if (!lazy_irq_pending())
113 static int dedicated_cede_loop(struct cpuidle_device
*dev
,
114 struct cpuidle_driver
*drv
,
117 unsigned long in_purr
;
120 idle_loop_prolog(&in_purr
, &kt_before
);
121 get_lppaca()->donate_dedicated_cpu
= 1;
123 ppc64_runlatch_off();
125 check_and_cede_processor();
127 get_lppaca()->donate_dedicated_cpu
= 0;
128 dev
->last_residency
=
129 (int)idle_loop_epilog(in_purr
, kt_before
);
133 static int shared_cede_loop(struct cpuidle_device
*dev
,
134 struct cpuidle_driver
*drv
,
137 unsigned long in_purr
;
140 idle_loop_prolog(&in_purr
, &kt_before
);
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
149 check_and_cede_processor();
151 dev
->last_residency
=
152 (int)idle_loop_epilog(in_purr
, kt_before
);
157 * States for dedicated partition case.
159 static struct cpuidle_state dedicated_states
[MAX_IDLE_STATE_COUNT
] = {
163 .flags
= CPUIDLE_FLAG_TIME_VALID
,
165 .target_residency
= 0,
166 .enter
= &snooze_loop
},
170 .flags
= CPUIDLE_FLAG_TIME_VALID
,
172 .target_residency
= 10,
173 .enter
= &dedicated_cede_loop
},
177 * States for shared partition case.
179 static struct cpuidle_state shared_states
[MAX_IDLE_STATE_COUNT
] = {
181 .name
= "Shared Cede",
182 .desc
= "Shared Cede",
183 .flags
= CPUIDLE_FLAG_TIME_VALID
,
185 .target_residency
= 0,
186 .enter
= &shared_cede_loop
},
189 int pseries_notify_cpuidle_add_cpu(int cpu
)
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
);
201 * pseries_cpuidle_driver_init()
203 static int pseries_cpuidle_driver_init(void)
206 struct cpuidle_driver
*drv
= &pseries_idle_driver
;
208 drv
->state_count
= 0;
210 for (idle_state
= 0; idle_state
< MAX_IDLE_STATE_COUNT
; ++idle_state
) {
212 if (idle_state
> max_idle_state
)
215 /* is the state not enabled? */
216 if (cpuidle_state_table
[idle_state
].enter
== NULL
)
219 drv
->states
[drv
->state_count
] = /* structure copy */
220 cpuidle_state_table
[idle_state
];
222 if (cpuidle_state_table
== dedicated_states
)
223 drv
->states
[drv
->state_count
].target_residency
=
224 __get_cpu_var(smt_snooze_delay
);
226 drv
->state_count
+= 1;
232 /* pseries_idle_devices_uninit(void)
233 * unregister cpuidle devices and de-allocate memory
235 static void pseries_idle_devices_uninit(void)
238 struct cpuidle_device
*dev
;
240 for_each_possible_cpu(i
) {
241 dev
= per_cpu_ptr(pseries_cpuidle_devices
, i
);
242 cpuidle_unregister_device(dev
);
245 free_percpu(pseries_cpuidle_devices
);
249 /* pseries_idle_devices_init()
250 * allocate, initialize and register cpuidle device
252 static int pseries_idle_devices_init(void)
255 struct cpuidle_driver
*drv
= &pseries_idle_driver
;
256 struct cpuidle_device
*dev
;
258 pseries_cpuidle_devices
= alloc_percpu(struct cpuidle_device
);
259 if (pseries_cpuidle_devices
== NULL
)
262 for_each_possible_cpu(i
) {
263 dev
= per_cpu_ptr(pseries_cpuidle_devices
, i
);
264 dev
->state_count
= drv
->state_count
;
266 if (cpuidle_register_device(dev
)) {
268 "cpuidle_register_device %d failed!\n", i
);
277 * pseries_idle_probe()
278 * Choose state table for shared versus dedicated partition
280 static int pseries_idle_probe(void)
283 if (!firmware_has_feature(FW_FEATURE_SPLPAR
))
286 if (cpuidle_disable
!= IDLE_NO_OVERRIDE
)
289 if (max_idle_state
== 0) {
290 printk(KERN_DEBUG
"pseries processor idle disabled.\n");
294 if (get_lppaca()->shared_proc
)
295 cpuidle_state_table
= shared_states
;
297 cpuidle_state_table
= dedicated_states
;
302 static int __init
pseries_processor_idle_init(void)
306 retval
= pseries_idle_probe();
310 pseries_cpuidle_driver_init();
311 retval
= cpuidle_register_driver(&pseries_idle_driver
);
313 printk(KERN_DEBUG
"Registration of pseries driver failed.\n");
317 retval
= pseries_idle_devices_init();
319 pseries_idle_devices_uninit();
320 cpuidle_unregister_driver(&pseries_idle_driver
);
324 printk(KERN_DEBUG
"pseries_idle_driver registered\n");
329 static void __exit
pseries_processor_idle_exit(void)
332 pseries_idle_devices_uninit();
333 cpuidle_unregister_driver(&pseries_idle_driver
);
338 module_init(pseries_processor_idle_init
);
339 module_exit(pseries_processor_idle_exit
);
341 MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
342 MODULE_DESCRIPTION("Cpuidle driver for POWER");
343 MODULE_LICENSE("GPL");