Commit 42d4dc3f authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Linus Torvalds
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[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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c60c3906

drivers/cpufreq/cpufreq.c

+89 −5
Original line number Diff line number Diff line
@@ -223,7 +223,7 @@ static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 
	}

	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);

	}
@@ -865,12 +865,91 @@ unsigned int cpufreq_get(unsigned int cpu) 
EXPORT_SYMBOL(cpufreq_get);





/**

 *	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 @@ static int cpufreq_resume(struct sys_device * sysdev) 
			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 @@ static int cpufreq_resume(struct sys_device * sysdev) 
			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 @@ out: 
static struct sysdev_driver cpufreq_sysdev_driver = {

	.add		= cpufreq_add_dev,

	.remove		= cpufreq_remove_dev,

	.suspend	= cpufreq_suspend,

	.resume		= cpufreq_resume,

};

include/linux/cpufreq.h

+4 −1
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ struct cpufreq_policy { 
#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 @@ struct cpufreq_driver { 


	/* 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 @@ struct cpufreq_driver { 
#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);

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