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>
16 #include <linux/slab.h>
18 #include <asm/machdep.h>
19 #include <asm/firmware.h>
21 #include <asm/runlatch.h>
23 #define MAX_POWERNV_IDLE_STATES 8
25 struct cpuidle_driver powernv_idle_driver
= {
26 .name
= "powernv_idle",
30 static int max_idle_state
;
31 static struct cpuidle_state
*cpuidle_state_table
;
32 static u64 snooze_timeout
;
33 static bool snooze_timeout_en
;
35 static int snooze_loop(struct cpuidle_device
*dev
,
36 struct cpuidle_driver
*drv
,
42 set_thread_flag(TIF_POLLING_NRFLAG
);
44 snooze_exit_time
= get_tb() + snooze_timeout
;
46 while (!need_resched()) {
49 if (snooze_timeout_en
&& get_tb() > snooze_exit_time
)
55 clear_thread_flag(TIF_POLLING_NRFLAG
);
60 static int nap_loop(struct cpuidle_device
*dev
,
61 struct cpuidle_driver
*drv
,
70 static int fastsleep_loop(struct cpuidle_device
*dev
,
71 struct cpuidle_driver
*drv
,
74 unsigned long old_lpcr
= mfspr(SPRN_LPCR
);
75 unsigned long new_lpcr
;
77 if (unlikely(system_state
< SYSTEM_RUNNING
))
81 /* Do not exit powersave upon decrementer as we've setup the timer
84 new_lpcr
&= ~LPCR_PECE1
;
86 mtspr(SPRN_LPCR
, new_lpcr
);
89 mtspr(SPRN_LPCR
, old_lpcr
);
95 * States for dedicated partition case.
97 static struct cpuidle_state powernv_states
[MAX_POWERNV_IDLE_STATES
] = {
102 .target_residency
= 0,
103 .enter
= &snooze_loop
},
106 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block
*n
,
107 unsigned long action
, void *hcpu
)
109 int hotcpu
= (unsigned long)hcpu
;
110 struct cpuidle_device
*dev
=
111 per_cpu(cpuidle_devices
, hotcpu
);
113 if (dev
&& cpuidle_get_driver()) {
116 case CPU_ONLINE_FROZEN
:
117 cpuidle_pause_and_lock();
118 cpuidle_enable_device(dev
);
119 cpuidle_resume_and_unlock();
123 case CPU_DEAD_FROZEN
:
124 cpuidle_pause_and_lock();
125 cpuidle_disable_device(dev
);
126 cpuidle_resume_and_unlock();
136 static struct notifier_block setup_hotplug_notifier
= {
137 .notifier_call
= powernv_cpuidle_add_cpu_notifier
,
141 * powernv_cpuidle_driver_init()
143 static int powernv_cpuidle_driver_init(void)
146 struct cpuidle_driver
*drv
= &powernv_idle_driver
;
148 drv
->state_count
= 0;
150 for (idle_state
= 0; idle_state
< max_idle_state
; ++idle_state
) {
151 /* Is the state not enabled? */
152 if (cpuidle_state_table
[idle_state
].enter
== NULL
)
155 drv
->states
[drv
->state_count
] = /* structure copy */
156 cpuidle_state_table
[idle_state
];
158 drv
->state_count
+= 1;
164 static int powernv_add_idle_states(void)
166 struct device_node
*power_mgt
;
167 int nr_idle_states
= 1; /* Snooze */
169 u32
*latency_ns
, *residency_ns
, *flags
;
172 /* Currently we have snooze statically defined */
174 power_mgt
= of_find_node_by_path("/ibm,opal/power-mgt");
176 pr_warn("opal: PowerMgmt Node not found\n");
180 /* Read values of any property to determine the num of idle states */
181 dt_idle_states
= of_property_count_u32_elems(power_mgt
, "ibm,cpu-idle-state-flags");
182 if (dt_idle_states
< 0) {
183 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
187 flags
= kzalloc(sizeof(*flags
) * dt_idle_states
, GFP_KERNEL
);
188 if (of_property_read_u32_array(power_mgt
,
189 "ibm,cpu-idle-state-flags", flags
, dt_idle_states
)) {
190 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
194 latency_ns
= kzalloc(sizeof(*latency_ns
) * dt_idle_states
, GFP_KERNEL
);
195 rc
= of_property_read_u32_array(power_mgt
,
196 "ibm,cpu-idle-state-latencies-ns", latency_ns
, dt_idle_states
);
198 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
199 goto out_free_latency
;
202 residency_ns
= kzalloc(sizeof(*residency_ns
) * dt_idle_states
, GFP_KERNEL
);
203 rc
= of_property_read_u32_array(power_mgt
,
204 "ibm,cpu-idle-state-residency-ns", residency_ns
, dt_idle_states
);
206 for (i
= 0; i
< dt_idle_states
; i
++) {
209 * Cpuidle accepts exit_latency and target_residency in us.
210 * Use default target_residency values if f/w does not expose it.
212 if (flags
[i
] & OPAL_PM_NAP_ENABLED
) {
214 strcpy(powernv_states
[nr_idle_states
].name
, "Nap");
215 strcpy(powernv_states
[nr_idle_states
].desc
, "Nap");
216 powernv_states
[nr_idle_states
].flags
= 0;
217 powernv_states
[nr_idle_states
].target_residency
= 100;
218 powernv_states
[nr_idle_states
].enter
= &nap_loop
;
219 } else if (flags
[i
] & OPAL_PM_SLEEP_ENABLED
||
220 flags
[i
] & OPAL_PM_SLEEP_ENABLED_ER1
) {
221 /* Add FASTSLEEP state */
222 strcpy(powernv_states
[nr_idle_states
].name
, "FastSleep");
223 strcpy(powernv_states
[nr_idle_states
].desc
, "FastSleep");
224 powernv_states
[nr_idle_states
].flags
= CPUIDLE_FLAG_TIMER_STOP
;
225 powernv_states
[nr_idle_states
].target_residency
= 300000;
226 powernv_states
[nr_idle_states
].enter
= &fastsleep_loop
;
229 powernv_states
[nr_idle_states
].exit_latency
=
230 ((unsigned int)latency_ns
[i
]) / 1000;
233 powernv_states
[nr_idle_states
].target_residency
=
234 ((unsigned int)residency_ns
[i
]) / 1000;
246 return nr_idle_states
;
250 * powernv_idle_probe()
251 * Choose state table for shared versus dedicated partition
253 static int powernv_idle_probe(void)
255 if (cpuidle_disable
!= IDLE_NO_OVERRIDE
)
258 if (firmware_has_feature(FW_FEATURE_OPALv3
)) {
259 cpuidle_state_table
= powernv_states
;
260 /* Device tree can indicate more idle states */
261 max_idle_state
= powernv_add_idle_states();
262 if (max_idle_state
> 1) {
263 snooze_timeout_en
= true;
264 snooze_timeout
= powernv_states
[1].target_residency
*
273 static int __init
powernv_processor_idle_init(void)
277 retval
= powernv_idle_probe();
281 powernv_cpuidle_driver_init();
282 retval
= cpuidle_register(&powernv_idle_driver
, NULL
);
284 printk(KERN_DEBUG
"Registration of powernv driver failed.\n");
288 register_cpu_notifier(&setup_hotplug_notifier
);
289 printk(KERN_DEBUG
"powernv_idle_driver registered\n");
293 device_initcall(powernv_processor_idle_init
);