[PATCH] Add suspend method to cpufreq core
In order to properly fix some issues with cpufreq vs. sleep on
PowerBooks, I had to add a suspend callback to the pmac_cpufreq driver.
I must force a switch to full speed before sleep and I switch back to
previous speed on resume.
I also added a driver flag to disable the warnings in suspend/resume
since it is expected in this case to have different speed (and I want it
to fixup the jiffies properly).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index b30001f..4fc0cb7 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -223,7 +223,7 @@
}
if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
(val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
- (val == CPUFREQ_RESUMECHANGE)) {
+ (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq, ci->new);
dprintk("scaling loops_per_jiffy to %lu for frequency %u kHz\n", loops_per_jiffy, ci->new);
}
@@ -866,11 +866,90 @@
/**
+ * cpufreq_suspend - let the low level driver prepare for suspend
+ */
+
+static int cpufreq_suspend(struct sys_device * sysdev, u32 state)
+{
+ int cpu = sysdev->id;
+ unsigned int ret = 0;
+ unsigned int cur_freq = 0;
+ struct cpufreq_policy *cpu_policy;
+
+ dprintk("resuming cpu %u\n", cpu);
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ /* we may be lax here as interrupts are off. Nonetheless
+ * we need to grab the correct cpu policy, as to check
+ * whether we really run on this CPU.
+ */
+
+ cpu_policy = cpufreq_cpu_get(cpu);
+ if (!cpu_policy)
+ return -EINVAL;
+
+ /* only handle each CPU group once */
+ if (unlikely(cpu_policy->cpu != cpu)) {
+ cpufreq_cpu_put(cpu_policy);
+ return 0;
+ }
+
+ if (cpufreq_driver->suspend) {
+ ret = cpufreq_driver->suspend(cpu_policy, state);
+ if (ret) {
+ printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
+ "step on CPU %u\n", cpu_policy->cpu);
+ cpufreq_cpu_put(cpu_policy);
+ return ret;
+ }
+ }
+
+
+ if (cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)
+ goto out;
+
+ if (cpufreq_driver->get)
+ cur_freq = cpufreq_driver->get(cpu_policy->cpu);
+
+ if (!cur_freq || !cpu_policy->cur) {
+ printk(KERN_ERR "cpufreq: suspend failed to assert current "
+ "frequency is what timing core thinks it is.\n");
+ goto out;
+ }
+
+ if (unlikely(cur_freq != cpu_policy->cur)) {
+ struct cpufreq_freqs freqs;
+
+ if (!(cpufreq_driver->flags & CPUFREQ_PM_NO_WARN))
+ printk(KERN_DEBUG "Warning: CPU frequency is %u, "
+ "cpufreq assumed %u kHz.\n",
+ cur_freq, cpu_policy->cur);
+
+ freqs.cpu = cpu;
+ freqs.old = cpu_policy->cur;
+ freqs.new = cur_freq;
+
+ notifier_call_chain(&cpufreq_transition_notifier_list,
+ CPUFREQ_SUSPENDCHANGE, &freqs);
+ adjust_jiffies(CPUFREQ_SUSPENDCHANGE, &freqs);
+
+ cpu_policy->cur = cur_freq;
+ }
+
+ out:
+ cpufreq_cpu_put(cpu_policy);
+ return 0;
+}
+
+/**
* cpufreq_resume - restore proper CPU frequency handling after resume
*
* 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
* 2.) if ->target and !CPUFREQ_CONST_LOOPS: verify we're in sync
- * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are restored.
+ * 3.) schedule call cpufreq_update_policy() ASAP as interrupts are
+ * restored.
*/
static int cpufreq_resume(struct sys_device * sysdev)
{
@@ -915,7 +994,9 @@
cur_freq = cpufreq_driver->get(cpu_policy->cpu);
if (!cur_freq || !cpu_policy->cur) {
- printk(KERN_ERR "cpufreq: resume failed to assert current frequency is what timing core thinks it is.\n");
+ printk(KERN_ERR "cpufreq: resume failed to assert "
+ "current frequency is what timing core "
+ "thinks it is.\n");
goto out;
}
@@ -923,13 +1004,15 @@
struct cpufreq_freqs freqs;
printk(KERN_WARNING "Warning: CPU frequency is %u, "
- "cpufreq assumed %u kHz.\n", cur_freq, cpu_policy->cur);
+ "cpufreq assumed %u kHz.\n",
+ cur_freq, cpu_policy->cur);
freqs.cpu = cpu;
freqs.old = cpu_policy->cur;
freqs.new = cur_freq;
- notifier_call_chain(&cpufreq_transition_notifier_list, CPUFREQ_RESUMECHANGE, &freqs);
+ notifier_call_chain(&cpufreq_transition_notifier_list,
+ CPUFREQ_RESUMECHANGE, &freqs);
adjust_jiffies(CPUFREQ_RESUMECHANGE, &freqs);
cpu_policy->cur = cur_freq;
@@ -945,6 +1028,7 @@
static struct sysdev_driver cpufreq_sysdev_driver = {
.add = cpufreq_add_dev,
.remove = cpufreq_remove_dev,
+ .suspend = cpufreq_suspend,
.resume = cpufreq_resume,
};
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 910eca3..f21af06 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -103,6 +103,7 @@
#define CPUFREQ_PRECHANGE (0)
#define CPUFREQ_POSTCHANGE (1)
#define CPUFREQ_RESUMECHANGE (8)
+#define CPUFREQ_SUSPENDCHANGE (9)
struct cpufreq_freqs {
unsigned int cpu; /* cpu nr */
@@ -200,6 +201,7 @@
/* optional */
int (*exit) (struct cpufreq_policy *policy);
+ int (*suspend) (struct cpufreq_policy *policy, u32 state);
int (*resume) (struct cpufreq_policy *policy);
struct freq_attr **attr;
};
@@ -211,7 +213,8 @@
#define CPUFREQ_CONST_LOOPS 0x02 /* loops_per_jiffy or other kernel
* "constants" aren't affected by
* frequency transitions */
-
+#define CPUFREQ_PM_NO_WARN 0x04 /* don't warn on suspend/resume speed
+ * mismatches */
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);