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 POWERNV_THRESHOLD_LATENCY_NS 200000
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
;
33 static u64 stop_psscr_table
[CPUIDLE_STATE_MAX
];
35 static u64 snooze_timeout
;
36 static bool snooze_timeout_en
;
38 static int snooze_loop(struct cpuidle_device
*dev
,
39 struct cpuidle_driver
*drv
,
45 set_thread_flag(TIF_POLLING_NRFLAG
);
47 snooze_exit_time
= get_tb() + snooze_timeout
;
49 while (!need_resched()) {
52 if (snooze_timeout_en
&& get_tb() > snooze_exit_time
)
58 clear_thread_flag(TIF_POLLING_NRFLAG
);
63 static int nap_loop(struct cpuidle_device
*dev
,
64 struct cpuidle_driver
*drv
,
73 /* Register for fastsleep only in oneshot mode of broadcast */
74 #ifdef CONFIG_TICK_ONESHOT
75 static int fastsleep_loop(struct cpuidle_device
*dev
,
76 struct cpuidle_driver
*drv
,
79 unsigned long old_lpcr
= mfspr(SPRN_LPCR
);
80 unsigned long new_lpcr
;
82 if (unlikely(system_state
< SYSTEM_RUNNING
))
86 /* Do not exit powersave upon decrementer as we've setup the timer
89 new_lpcr
&= ~LPCR_PECE1
;
91 mtspr(SPRN_LPCR
, new_lpcr
);
94 mtspr(SPRN_LPCR
, old_lpcr
);
100 static int stop_loop(struct cpuidle_device
*dev
,
101 struct cpuidle_driver
*drv
,
104 ppc64_runlatch_off();
105 power9_idle_stop(stop_psscr_table
[index
]);
111 * States for dedicated partition case.
113 static struct cpuidle_state powernv_states
[CPUIDLE_STATE_MAX
] = {
118 .target_residency
= 0,
119 .enter
= snooze_loop
},
122 static int powernv_cpuidle_add_cpu_notifier(struct notifier_block
*n
,
123 unsigned long action
, void *hcpu
)
125 int hotcpu
= (unsigned long)hcpu
;
126 struct cpuidle_device
*dev
=
127 per_cpu(cpuidle_devices
, hotcpu
);
129 if (dev
&& cpuidle_get_driver()) {
132 case CPU_ONLINE_FROZEN
:
133 cpuidle_pause_and_lock();
134 cpuidle_enable_device(dev
);
135 cpuidle_resume_and_unlock();
139 case CPU_DEAD_FROZEN
:
140 cpuidle_pause_and_lock();
141 cpuidle_disable_device(dev
);
142 cpuidle_resume_and_unlock();
152 static struct notifier_block setup_hotplug_notifier
= {
153 .notifier_call
= powernv_cpuidle_add_cpu_notifier
,
157 * powernv_cpuidle_driver_init()
159 static int powernv_cpuidle_driver_init(void)
162 struct cpuidle_driver
*drv
= &powernv_idle_driver
;
164 drv
->state_count
= 0;
166 for (idle_state
= 0; idle_state
< max_idle_state
; ++idle_state
) {
167 /* Is the state not enabled? */
168 if (cpuidle_state_table
[idle_state
].enter
== NULL
)
171 drv
->states
[drv
->state_count
] = /* structure copy */
172 cpuidle_state_table
[idle_state
];
174 drv
->state_count
+= 1;
180 static int powernv_add_idle_states(void)
182 struct device_node
*power_mgt
;
183 int nr_idle_states
= 1; /* Snooze */
185 u32 latency_ns
[CPUIDLE_STATE_MAX
];
186 u32 residency_ns
[CPUIDLE_STATE_MAX
];
187 u32 flags
[CPUIDLE_STATE_MAX
];
188 u64 psscr_val
[CPUIDLE_STATE_MAX
];
189 const char *names
[CPUIDLE_STATE_MAX
];
192 /* Currently we have snooze statically defined */
194 power_mgt
= of_find_node_by_path("/ibm,opal/power-mgt");
196 pr_warn("opal: PowerMgmt Node not found\n");
200 /* Read values of any property to determine the num of idle states */
201 dt_idle_states
= of_property_count_u32_elems(power_mgt
, "ibm,cpu-idle-state-flags");
202 if (dt_idle_states
< 0) {
203 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
208 * Since snooze is used as first idle state, max idle states allowed is
209 * CPUIDLE_STATE_MAX -1
211 if (dt_idle_states
> CPUIDLE_STATE_MAX
- 1) {
212 pr_warn("cpuidle-powernv: discovered idle states more than allowed");
213 dt_idle_states
= CPUIDLE_STATE_MAX
- 1;
216 if (of_property_read_u32_array(power_mgt
,
217 "ibm,cpu-idle-state-flags", flags
, dt_idle_states
)) {
218 pr_warn("cpuidle-powernv : missing ibm,cpu-idle-state-flags in DT\n");
222 if (of_property_read_u32_array(power_mgt
,
223 "ibm,cpu-idle-state-latencies-ns", latency_ns
,
225 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
228 if (of_property_read_string_array(power_mgt
,
229 "ibm,cpu-idle-state-names", names
, dt_idle_states
) < 0) {
230 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
235 * If the idle states use stop instruction, probe for psscr values
236 * which are necessary to specify required stop level.
238 if (flags
[0] & (OPAL_PM_STOP_INST_FAST
| OPAL_PM_STOP_INST_DEEP
))
239 if (of_property_read_u64_array(power_mgt
,
240 "ibm,cpu-idle-state-psscr", psscr_val
, dt_idle_states
)) {
241 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
245 rc
= of_property_read_u32_array(power_mgt
,
246 "ibm,cpu-idle-state-residency-ns", residency_ns
, dt_idle_states
);
248 for (i
= 0; i
< dt_idle_states
; i
++) {
250 * If an idle state has exit latency beyond
251 * POWERNV_THRESHOLD_LATENCY_NS then don't use it
254 if (latency_ns
[i
] > POWERNV_THRESHOLD_LATENCY_NS
)
258 * Cpuidle accepts exit_latency and target_residency in us.
259 * Use default target_residency values if f/w does not expose it.
261 if (flags
[i
] & OPAL_PM_NAP_ENABLED
) {
263 strcpy(powernv_states
[nr_idle_states
].name
, "Nap");
264 strcpy(powernv_states
[nr_idle_states
].desc
, "Nap");
265 powernv_states
[nr_idle_states
].flags
= 0;
266 powernv_states
[nr_idle_states
].target_residency
= 100;
267 powernv_states
[nr_idle_states
].enter
= nap_loop
;
268 } else if ((flags
[i
] & OPAL_PM_STOP_INST_FAST
) &&
269 !(flags
[i
] & OPAL_PM_TIMEBASE_STOP
)) {
270 strncpy(powernv_states
[nr_idle_states
].name
,
271 names
[i
], CPUIDLE_NAME_LEN
);
272 strncpy(powernv_states
[nr_idle_states
].desc
,
273 names
[i
], CPUIDLE_NAME_LEN
);
274 powernv_states
[nr_idle_states
].flags
= 0;
276 powernv_states
[nr_idle_states
].enter
= stop_loop
;
277 stop_psscr_table
[nr_idle_states
] = psscr_val
[i
];
281 * All cpuidle states with CPUIDLE_FLAG_TIMER_STOP set must come
282 * within this config dependency check.
284 #ifdef CONFIG_TICK_ONESHOT
285 if (flags
[i
] & OPAL_PM_SLEEP_ENABLED
||
286 flags
[i
] & OPAL_PM_SLEEP_ENABLED_ER1
) {
287 /* Add FASTSLEEP state */
288 strcpy(powernv_states
[nr_idle_states
].name
, "FastSleep");
289 strcpy(powernv_states
[nr_idle_states
].desc
, "FastSleep");
290 powernv_states
[nr_idle_states
].flags
= CPUIDLE_FLAG_TIMER_STOP
;
291 powernv_states
[nr_idle_states
].target_residency
= 300000;
292 powernv_states
[nr_idle_states
].enter
= fastsleep_loop
;
293 } else if ((flags
[i
] & OPAL_PM_STOP_INST_DEEP
) &&
294 (flags
[i
] & OPAL_PM_TIMEBASE_STOP
)) {
295 strncpy(powernv_states
[nr_idle_states
].name
,
296 names
[i
], CPUIDLE_NAME_LEN
);
297 strncpy(powernv_states
[nr_idle_states
].desc
,
298 names
[i
], CPUIDLE_NAME_LEN
);
300 powernv_states
[nr_idle_states
].flags
= CPUIDLE_FLAG_TIMER_STOP
;
301 powernv_states
[nr_idle_states
].enter
= stop_loop
;
302 stop_psscr_table
[nr_idle_states
] = psscr_val
[i
];
305 powernv_states
[nr_idle_states
].exit_latency
=
306 ((unsigned int)latency_ns
[i
]) / 1000;
309 powernv_states
[nr_idle_states
].target_residency
=
310 ((unsigned int)residency_ns
[i
]) / 1000;
316 return nr_idle_states
;
320 * powernv_idle_probe()
321 * Choose state table for shared versus dedicated partition
323 static int powernv_idle_probe(void)
325 if (cpuidle_disable
!= IDLE_NO_OVERRIDE
)
328 if (firmware_has_feature(FW_FEATURE_OPAL
)) {
329 cpuidle_state_table
= powernv_states
;
330 /* Device tree can indicate more idle states */
331 max_idle_state
= powernv_add_idle_states();
332 if (max_idle_state
> 1) {
333 snooze_timeout_en
= true;
334 snooze_timeout
= powernv_states
[1].target_residency
*
343 static int __init
powernv_processor_idle_init(void)
347 retval
= powernv_idle_probe();
351 powernv_cpuidle_driver_init();
352 retval
= cpuidle_register(&powernv_idle_driver
, NULL
);
354 printk(KERN_DEBUG
"Registration of powernv driver failed.\n");
358 register_cpu_notifier(&setup_hotplug_notifier
);
359 printk(KERN_DEBUG
"powernv_idle_driver registered\n");
363 device_initcall(powernv_processor_idle_init
);