[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 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -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,
 };
 

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 910eca3..f21af06 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -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);