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Subject[PATCH 06/10] powerpc: macintosh: Switch to QoS requests instead of cpufreq notifier
Date
The cpufreq core now takes the min/max frequency constraints via QoS
requests and the CPUFREQ_ADJUST notifier shall get removed later on.

Switch over to using the QoS request for maximum frequency constraint
for windfarm_cpufreq_clamp driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/macintosh/windfarm_cpufreq_clamp.c | 77 ++++++++++++++--------
1 file changed, 50 insertions(+), 27 deletions(-)

diff --git a/drivers/macintosh/windfarm_cpufreq_clamp.c b/drivers/macintosh/windfarm_cpufreq_clamp.c
index 52fd5fca89a0..705c6200814b 100644
--- a/drivers/macintosh/windfarm_cpufreq_clamp.c
+++ b/drivers/macintosh/windfarm_cpufreq_clamp.c
@@ -3,9 +3,11 @@
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
+#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
+#include <linux/cpu.h>
#include <linux/cpufreq.h>

#include <asm/prom.h>
@@ -16,36 +18,24 @@

static int clamped;
static struct wf_control *clamp_control;
-
-static int clamp_notifier_call(struct notifier_block *self,
- unsigned long event, void *data)
-{
- struct cpufreq_policy *p = data;
- unsigned long max_freq;
-
- if (event != CPUFREQ_ADJUST)
- return 0;
-
- max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
- cpufreq_verify_within_limits(p, 0, max_freq);
-
- return 0;
-}
-
-static struct notifier_block clamp_notifier = {
- .notifier_call = clamp_notifier_call,
-};
+static struct dev_pm_qos_request qos_req;
+static unsigned int min_freq, max_freq;

static int clamp_set(struct wf_control *ct, s32 value)
{
- if (value)
+ unsigned int freq;
+
+ if (value) {
+ freq = min_freq;
printk(KERN_INFO "windfarm: Clamping CPU frequency to "
"minimum !\n");
- else
+ } else {
+ freq = max_freq;
printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
+ }
clamped = value;
- cpufreq_update_policy(0);
- return 0;
+
+ return dev_pm_qos_update_request(&qos_req, freq);
}

static int clamp_get(struct wf_control *ct, s32 *value)
@@ -74,27 +64,60 @@ static const struct wf_control_ops clamp_ops = {

static int __init wf_cpufreq_clamp_init(void)
{
+ struct cpufreq_policy *policy;
struct wf_control *clamp;
+ struct device *dev;
+ int ret;
+
+ policy = cpufreq_cpu_get(0);
+ if (!policy) {
+ pr_warn("%s: cpufreq policy not found cpu0\n", __func__);
+ return -EPROBE_DEFER;
+ }
+
+ min_freq = policy->cpuinfo.min_freq;
+ max_freq = policy->cpuinfo.max_freq;
+ cpufreq_cpu_put(policy);
+
+ dev = get_cpu_device(0);
+ if (unlikely(!dev)) {
+ pr_warn("%s: No cpu device for cpu0\n", __func__);
+ return -ENODEV;
+ }

clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
if (clamp == NULL)
return -ENOMEM;
- cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
+
+ ret = dev_pm_qos_add_request(dev, &qos_req, DEV_PM_QOS_MAX_FREQUENCY,
+ max_freq);
+ if (ret < 0) {
+ pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
+ ret);
+ goto free;
+ }
+
clamp->ops = &clamp_ops;
clamp->name = "cpufreq-clamp";
- if (wf_register_control(clamp))
+ ret = wf_register_control(clamp);
+ if (ret)
goto fail;
clamp_control = clamp;
return 0;
fail:
+ dev_pm_qos_remove_request(&qos_req);
+
+ free:
kfree(clamp);
- return -ENODEV;
+ return ret;
}

static void __exit wf_cpufreq_clamp_exit(void)
{
- if (clamp_control)
+ if (clamp_control) {
wf_unregister_control(clamp_control);
+ dev_pm_qos_remove_request(&qos_req);
+ }
}


--
2.21.0.rc0.269.g1a574e7a288b
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