2 * cpuidle-powernv - idle state cpuidle driver.
3 * Adapted from drivers/cpuidle/cpuidle-pseries
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/moduleparam.h>
11 #include <linux/cpuidle.h>
12 #include <linux/cpu.h>
13 #include <linux/notifier.h>
14 #include <linux/clockchips.h>
17 #include <asm/machdep.h>
18 #include <asm/firmware.h>
19 #include <asm/runlatch.h>
21 /* Flags and constants used in PowerNV platform */
23 #define MAX_POWERNV_IDLE_STATES 8
24 #define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */
25 #define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */
27 struct cpuidle_driver powernv_idle_driver
= {
28 .name
= "powernv_idle",
32 static int max_idle_state
;
33 static struct cpuidle_state
*cpuidle_state_table
;
35 static int snooze_loop(struct cpuidle_device
*dev
,
36 struct cpuidle_driver
*drv
,
40 set_thread_flag(TIF_POLLING_NRFLAG
);
43 while (!need_resched()) {
50 clear_thread_flag(TIF_POLLING_NRFLAG
);
55 static int nap_loop(struct cpuidle_device
*dev
,
56 struct cpuidle_driver
*drv
,
65 static int fastsleep_loop(struct cpuidle_device
*dev
,
66 struct cpuidle_driver
*drv
,
69 unsigned long old_lpcr
= mfspr(SPRN_LPCR
);
70 unsigned long new_lpcr
;
72 if (unlikely(system_state
< SYSTEM_RUNNING
))
76 new_lpcr
&= ~(LPCR_MER
| LPCR_PECE
); /* lpcr[mer] must be 0 */
78 /* exit powersave upon external interrupt, but not decrementer
81 new_lpcr
|= LPCR_PECE0
;
83 mtspr(SPRN_LPCR
, new_lpcr
);
86 mtspr(SPRN_LPCR
, old_lpcr
);
92 * States for dedicated partition case.
94 static struct cpuidle_state powernv_states
[MAX_POWERNV_IDLE_STATES
] = {
98 .flags
= CPUIDLE_FLAG_TIME_VALID
,
100 .target_residency
= 0,
101 .enter
= &snooze_loop
},
104 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block
*n
,
105 unsigned long action
, void *hcpu
)
107 int hotcpu
= (unsigned long)hcpu
;
108 struct cpuidle_device
*dev
=
109 per_cpu(cpuidle_devices
, hotcpu
);
111 if (dev
&& cpuidle_get_driver()) {
114 case CPU_ONLINE_FROZEN
:
115 cpuidle_pause_and_lock();
116 cpuidle_enable_device(dev
);
117 cpuidle_resume_and_unlock();
121 case CPU_DEAD_FROZEN
:
122 cpuidle_pause_and_lock();
123 cpuidle_disable_device(dev
);
124 cpuidle_resume_and_unlock();
134 static struct notifier_block setup_hotplug_notifier
= {
135 .notifier_call
= powernv_cpuidle_add_cpu_notifier
,
139 * powernv_cpuidle_driver_init()
141 static int powernv_cpuidle_driver_init(void)
144 struct cpuidle_driver
*drv
= &powernv_idle_driver
;
146 drv
->state_count
= 0;
148 for (idle_state
= 0; idle_state
< max_idle_state
; ++idle_state
) {
149 /* Is the state not enabled? */
150 if (cpuidle_state_table
[idle_state
].enter
== NULL
)
153 drv
->states
[drv
->state_count
] = /* structure copy */
154 cpuidle_state_table
[idle_state
];
156 drv
->state_count
+= 1;
162 static int powernv_add_idle_states(void)
164 struct device_node
*power_mgt
;
165 struct property
*prop
;
166 int nr_idle_states
= 1; /* Snooze */
171 /* Currently we have snooze statically defined */
173 power_mgt
= of_find_node_by_path("/ibm,opal/power-mgt");
175 pr_warn("opal: PowerMgmt Node not found\n");
176 return nr_idle_states
;
179 prop
= of_find_property(power_mgt
, "ibm,cpu-idle-state-flags", NULL
);
181 pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
182 return nr_idle_states
;
185 dt_idle_states
= prop
->length
/ sizeof(u32
);
186 flags
= (u32
*) prop
->value
;
188 for (i
= 0; i
< dt_idle_states
; i
++) {
190 if (flags
[i
] & IDLE_USE_INST_NAP
) {
192 strcpy(powernv_states
[nr_idle_states
].name
, "Nap");
193 strcpy(powernv_states
[nr_idle_states
].desc
, "Nap");
194 powernv_states
[nr_idle_states
].flags
= CPUIDLE_FLAG_TIME_VALID
;
195 powernv_states
[nr_idle_states
].exit_latency
= 10;
196 powernv_states
[nr_idle_states
].target_residency
= 100;
197 powernv_states
[nr_idle_states
].enter
= &nap_loop
;
201 if (flags
[i
] & IDLE_USE_INST_SLEEP
) {
202 /* Add FASTSLEEP state */
203 strcpy(powernv_states
[nr_idle_states
].name
, "FastSleep");
204 strcpy(powernv_states
[nr_idle_states
].desc
, "FastSleep");
205 powernv_states
[nr_idle_states
].flags
=
206 CPUIDLE_FLAG_TIME_VALID
| CPUIDLE_FLAG_TIMER_STOP
;
207 powernv_states
[nr_idle_states
].exit_latency
= 300;
208 powernv_states
[nr_idle_states
].target_residency
= 1000000;
209 powernv_states
[nr_idle_states
].enter
= &fastsleep_loop
;
214 return nr_idle_states
;
218 * powernv_idle_probe()
219 * Choose state table for shared versus dedicated partition
221 static int powernv_idle_probe(void)
223 if (cpuidle_disable
!= IDLE_NO_OVERRIDE
)
226 if (firmware_has_feature(FW_FEATURE_OPALv3
)) {
227 cpuidle_state_table
= powernv_states
;
228 /* Device tree can indicate more idle states */
229 max_idle_state
= powernv_add_idle_states();
236 static int __init
powernv_processor_idle_init(void)
240 retval
= powernv_idle_probe();
244 powernv_cpuidle_driver_init();
245 retval
= cpuidle_register(&powernv_idle_driver
, NULL
);
247 printk(KERN_DEBUG
"Registration of powernv driver failed.\n");
251 register_cpu_notifier(&setup_hotplug_notifier
);
252 printk(KERN_DEBUG
"powernv_idle_driver registered\n");
256 device_initcall(powernv_processor_idle_init
);