* [PATCH v3 20/28] ARM: tegra: cpufreq: Disable cpufreq during suspend [not found] <Message-ID: <AANLkTimK7vD6mrPXyRdx331mCnRNLnajCRONT=MzQHwW@mail.gmail.com> @ 2011-01-25 2:42 ` Colin Cross 0 siblings, 0 replies; 2+ messages in thread From: Colin Cross @ 2011-01-25 2:42 UTC (permalink / raw) To: linux-arm-kernel On Tegra, calling clk_set_rate on the CPU clock may call into the regulator API. If the regulator driver that controls the CPU voltage rail has been suspended, this can lead to attempted communication with a hardware block that has already been turned off. Adds a SUSPEND_PREPARE notification hook to drop the frequency to the lowest possible during suspend. Also adds 216MHz (off of PLLP) as the lowest CPU frequency, which allows PLLX to be turned off. Signed-off-by: Colin Cross <ccross@android.com> --- v3: Updated commit message to clarify issues with regulator api arch/arm/mach-tegra/cpu-tegra.c | 75 +++++++++++++++++++++++++++++++-------- 1 files changed, 60 insertions(+), 15 deletions(-) diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c index fea5719..ad26a9f 100644 --- a/arch/arm/mach-tegra/cpu-tegra.c +++ b/arch/arm/mach-tegra/cpu-tegra.c @@ -28,6 +28,7 @@ #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> +#include <linux/suspend.h> #include <asm/system.h> @@ -36,14 +37,15 @@ /* Frequency table index must be sequential starting at 0 */ static struct cpufreq_frequency_table freq_table[] = { - { 0, 312000 }, - { 1, 456000 }, - { 2, 608000 }, - { 3, 760000 }, - { 4, 816000 }, - { 5, 912000 }, - { 6, 1000000 }, - { 7, CPUFREQ_TABLE_END }, + { 0, 216000 }, + { 1, 312000 }, + { 2, 456000 }, + { 3, 608000 }, + { 4, 760000 }, + { 5, 816000 }, + { 6, 912000 }, + { 7, 1000000 }, + { 8, CPUFREQ_TABLE_END }, }; #define NUM_CPUS 2 @@ -51,6 +53,8 @@ static struct cpufreq_frequency_table freq_table[] = { static struct clk *cpu_clk; static unsigned long target_cpu_speed[NUM_CPUS]; +static DEFINE_MUTEX(tegra_cpu_lock); +static bool is_suspended; int tegra_verify_speed(struct cpufreq_policy *policy) { @@ -68,16 +72,11 @@ unsigned int tegra_getspeed(unsigned int cpu) return rate; } -static int tegra_update_cpu_speed(void) +static int tegra_update_cpu_speed(unsigned long rate) { - int i; - unsigned long rate = 0; int ret = 0; struct cpufreq_freqs freqs; - for_each_online_cpu(i) - rate = max(rate, target_cpu_speed[i]); - freqs.old = tegra_getspeed(0); freqs.new = rate; @@ -105,12 +104,30 @@ static int tegra_update_cpu_speed(void) return 0; } +static unsigned long tegra_cpu_highest_speed(void) +{ + unsigned long rate = 0; + int i; + + for_each_online_cpu(i) + rate = max(rate, target_cpu_speed[i]); + return rate; +} + static int tegra_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int idx; unsigned int freq; + int ret = 0; + + mutex_lock(&tegra_cpu_lock); + + if (is_suspended) { + ret = -EBUSY; + goto out; + } cpufreq_frequency_table_target(policy, freq_table, target_freq, relation, &idx); @@ -119,9 +136,34 @@ static int tegra_target(struct cpufreq_policy *policy, target_cpu_speed[policy->cpu] = freq; - return tegra_update_cpu_speed(); + ret = tegra_update_cpu_speed(tegra_cpu_highest_speed()); + +out: + mutex_unlock(&tegra_cpu_lock); + return ret; } +static int tegra_pm_notify(struct notifier_block *nb, unsigned long event, + void *dummy) +{ + mutex_lock(&tegra_cpu_lock); + if (event == PM_SUSPEND_PREPARE) { + is_suspended = true; + pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n", + freq_table[0].frequency); + tegra_update_cpu_speed(freq_table[0].frequency); + } else if (event == PM_POST_SUSPEND) { + is_suspended = false; + } + mutex_unlock(&tegra_cpu_lock); + + return NOTIFY_OK; +} + +static struct notifier_block tegra_cpu_pm_notifier = { + .notifier_call = tegra_pm_notify, +}; + static int tegra_cpu_init(struct cpufreq_policy *policy) { if (policy->cpu >= NUM_CPUS) @@ -142,6 +184,9 @@ static int tegra_cpu_init(struct cpufreq_policy *policy) policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; cpumask_copy(policy->related_cpus, cpu_possible_mask); + if (policy->cpu == 0) + register_pm_notifier(&tegra_cpu_pm_notifier); + return 0; } -- 1.7.3.1 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH v3 20/28] ARM: tegra: cpufreq: Disable cpufreq during suspend @ 2011-01-25 2:42 ` Colin Cross 0 siblings, 0 replies; 2+ messages in thread From: Colin Cross @ 2011-01-25 2:42 UTC (permalink / raw) To: linux-tegra Cc: linux-arm-kernel, olof, konkers, broonie, Colin Cross, Russell King, linux-kernel On Tegra, calling clk_set_rate on the CPU clock may call into the regulator API. If the regulator driver that controls the CPU voltage rail has been suspended, this can lead to attempted communication with a hardware block that has already been turned off. Adds a SUSPEND_PREPARE notification hook to drop the frequency to the lowest possible during suspend. Also adds 216MHz (off of PLLP) as the lowest CPU frequency, which allows PLLX to be turned off. Signed-off-by: Colin Cross <ccross@android.com> --- v3: Updated commit message to clarify issues with regulator api arch/arm/mach-tegra/cpu-tegra.c | 75 +++++++++++++++++++++++++++++++-------- 1 files changed, 60 insertions(+), 15 deletions(-) diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c index fea5719..ad26a9f 100644 --- a/arch/arm/mach-tegra/cpu-tegra.c +++ b/arch/arm/mach-tegra/cpu-tegra.c @@ -28,6 +28,7 @@ #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> +#include <linux/suspend.h> #include <asm/system.h> @@ -36,14 +37,15 @@ /* Frequency table index must be sequential starting at 0 */ static struct cpufreq_frequency_table freq_table[] = { - { 0, 312000 }, - { 1, 456000 }, - { 2, 608000 }, - { 3, 760000 }, - { 4, 816000 }, - { 5, 912000 }, - { 6, 1000000 }, - { 7, CPUFREQ_TABLE_END }, + { 0, 216000 }, + { 1, 312000 }, + { 2, 456000 }, + { 3, 608000 }, + { 4, 760000 }, + { 5, 816000 }, + { 6, 912000 }, + { 7, 1000000 }, + { 8, CPUFREQ_TABLE_END }, }; #define NUM_CPUS 2 @@ -51,6 +53,8 @@ static struct cpufreq_frequency_table freq_table[] = { static struct clk *cpu_clk; static unsigned long target_cpu_speed[NUM_CPUS]; +static DEFINE_MUTEX(tegra_cpu_lock); +static bool is_suspended; int tegra_verify_speed(struct cpufreq_policy *policy) { @@ -68,16 +72,11 @@ unsigned int tegra_getspeed(unsigned int cpu) return rate; } -static int tegra_update_cpu_speed(void) +static int tegra_update_cpu_speed(unsigned long rate) { - int i; - unsigned long rate = 0; int ret = 0; struct cpufreq_freqs freqs; - for_each_online_cpu(i) - rate = max(rate, target_cpu_speed[i]); - freqs.old = tegra_getspeed(0); freqs.new = rate; @@ -105,12 +104,30 @@ static int tegra_update_cpu_speed(void) return 0; } +static unsigned long tegra_cpu_highest_speed(void) +{ + unsigned long rate = 0; + int i; + + for_each_online_cpu(i) + rate = max(rate, target_cpu_speed[i]); + return rate; +} + static int tegra_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int idx; unsigned int freq; + int ret = 0; + + mutex_lock(&tegra_cpu_lock); + + if (is_suspended) { + ret = -EBUSY; + goto out; + } cpufreq_frequency_table_target(policy, freq_table, target_freq, relation, &idx); @@ -119,9 +136,34 @@ static int tegra_target(struct cpufreq_policy *policy, target_cpu_speed[policy->cpu] = freq; - return tegra_update_cpu_speed(); + ret = tegra_update_cpu_speed(tegra_cpu_highest_speed()); + +out: + mutex_unlock(&tegra_cpu_lock); + return ret; } +static int tegra_pm_notify(struct notifier_block *nb, unsigned long event, + void *dummy) +{ + mutex_lock(&tegra_cpu_lock); + if (event == PM_SUSPEND_PREPARE) { + is_suspended = true; + pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n", + freq_table[0].frequency); + tegra_update_cpu_speed(freq_table[0].frequency); + } else if (event == PM_POST_SUSPEND) { + is_suspended = false; + } + mutex_unlock(&tegra_cpu_lock); + + return NOTIFY_OK; +} + +static struct notifier_block tegra_cpu_pm_notifier = { + .notifier_call = tegra_pm_notify, +}; + static int tegra_cpu_init(struct cpufreq_policy *policy) { if (policy->cpu >= NUM_CPUS) @@ -142,6 +184,9 @@ static int tegra_cpu_init(struct cpufreq_policy *policy) policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; cpumask_copy(policy->related_cpus, cpu_possible_mask); + if (policy->cpu == 0) + register_pm_notifier(&tegra_cpu_pm_notifier); + return 0; } -- 1.7.3.1 ^ permalink raw reply related [flat|nested] 2+ messages in thread
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[not found] <Message-ID: <AANLkTimK7vD6mrPXyRdx331mCnRNLnajCRONT=MzQHwW@mail.gmail.com>
2011-01-25 2:42 ` [PATCH v3 20/28] ARM: tegra: cpufreq: Disable cpufreq during suspend Colin Cross
2011-01-25 2:42 ` Colin Cross
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