diff options
Diffstat (limited to 'drivers/cpufreq/exynos4210-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/exynos4210-cpufreq.c | 106 |
1 files changed, 102 insertions, 4 deletions
diff --git a/drivers/cpufreq/exynos4210-cpufreq.c b/drivers/cpufreq/exynos4210-cpufreq.c index 6f887573ce94..ab9741fab92e 100644 --- a/drivers/cpufreq/exynos4210-cpufreq.c +++ b/drivers/cpufreq/exynos4210-cpufreq.c @@ -17,6 +17,8 @@ #include <linux/slab.h> #include <linux/regulator/consumer.h> #include <linux/cpufreq.h> +#include <linux/notifier.h> +#include <linux/suspend.h> #include <mach/map.h> #include <mach/regs-clock.h> @@ -36,6 +38,10 @@ static struct regulator *int_regulator; static struct cpufreq_freqs freqs; static unsigned int memtype; +static unsigned int locking_frequency; +static bool frequency_locked; +static DEFINE_MUTEX(cpufreq_lock); + enum exynos4_memory_type { DDR2 = 4, LPDDR2, @@ -405,22 +411,32 @@ static int exynos4_target(struct cpufreq_policy *policy, { unsigned int index, old_index; unsigned int arm_volt, int_volt; + int err = -EINVAL; freqs.old = exynos4_getspeed(policy->cpu); + mutex_lock(&cpufreq_lock); + + if (frequency_locked && target_freq != locking_frequency) { + err = -EAGAIN; + goto out; + } + if (cpufreq_frequency_table_target(policy, exynos4_freq_table, freqs.old, relation, &old_index)) - return -EINVAL; + goto out; if (cpufreq_frequency_table_target(policy, exynos4_freq_table, target_freq, relation, &index)) - return -EINVAL; + goto out; + + err = 0; freqs.new = exynos4_freq_table[index].frequency; freqs.cpu = policy->cpu; if (freqs.new == freqs.old) - return 0; + goto out; /* get the voltage value */ arm_volt = exynos4_volt_table[index].arm_volt; @@ -447,10 +463,16 @@ static int exynos4_target(struct cpufreq_policy *policy, cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); - return 0; +out: + mutex_unlock(&cpufreq_lock); + return err; } #ifdef CONFIG_PM +/* + * These suspend/resume are used as syscore_ops, it is already too + * late to set regulator voltages at this stage. + */ static int exynos4_cpufreq_suspend(struct cpufreq_policy *policy) { return 0; @@ -462,6 +484,78 @@ static int exynos4_cpufreq_resume(struct cpufreq_policy *policy) } #endif +/** + * exynos4_cpufreq_pm_notifier - block CPUFREQ's activities in suspend-resume + * context + * @notifier + * @pm_event + * @v + * + * While frequency_locked == true, target() ignores every frequency but + * locking_frequency. The locking_frequency value is the initial frequency, + * which is set by the bootloader. In order to eliminate possible + * inconsistency in clock values, we save and restore frequencies during + * suspend and resume and block CPUFREQ activities. Note that the standard + * suspend/resume cannot be used as they are too deep (syscore_ops) for + * regulator actions. + */ +static int exynos4_cpufreq_pm_notifier(struct notifier_block *notifier, + unsigned long pm_event, void *v) +{ + struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */ + static unsigned int saved_frequency; + unsigned int temp; + + mutex_lock(&cpufreq_lock); + switch (pm_event) { + case PM_SUSPEND_PREPARE: + if (frequency_locked) + goto out; + frequency_locked = true; + + if (locking_frequency) { + saved_frequency = exynos4_getspeed(0); + + mutex_unlock(&cpufreq_lock); + exynos4_target(policy, locking_frequency, + CPUFREQ_RELATION_H); + mutex_lock(&cpufreq_lock); + } + + break; + case PM_POST_SUSPEND: + + if (saved_frequency) { + /* + * While frequency_locked, only locking_frequency + * is valid for target(). In order to use + * saved_frequency while keeping frequency_locked, + * we temporarly overwrite locking_frequency. + */ + temp = locking_frequency; + locking_frequency = saved_frequency; + + mutex_unlock(&cpufreq_lock); + exynos4_target(policy, locking_frequency, + CPUFREQ_RELATION_H); + mutex_lock(&cpufreq_lock); + + locking_frequency = temp; + } + + frequency_locked = false; + break; + } +out: + mutex_unlock(&cpufreq_lock); + + return NOTIFY_OK; +} + +static struct notifier_block exynos4_cpufreq_nb = { + .notifier_call = exynos4_cpufreq_pm_notifier, +}; + static int exynos4_cpufreq_cpu_init(struct cpufreq_policy *policy) { int ret; @@ -522,6 +616,8 @@ static int __init exynos4_cpufreq_init(void) if (IS_ERR(cpu_clk)) return PTR_ERR(cpu_clk); + locking_frequency = exynos4_getspeed(0); + moutcore = clk_get(NULL, "moutcore"); if (IS_ERR(moutcore)) goto out; @@ -561,6 +657,8 @@ static int __init exynos4_cpufreq_init(void) printk(KERN_DEBUG "%s: memtype= 0x%x\n", __func__, memtype); } + register_pm_notifier(&exynos4_cpufreq_nb); + return cpufreq_register_driver(&exynos4_driver); out: |