On 05/20/2015 10:44 AM, Lorenzo Pieralisi wrote:
> On Tue, May 19, 2015 at 03:49:12PM +0100, Tomeu Vizoso wrote:
>> This callback is expected to do the same as enter() but it has to
>> guarantee that interrupts aren't enabled at any point in its execution,
>> as the tick is frozen.
>>
>> It will be called when the system goes to suspend-to-idle and will
>> reduce power usage because CPUs won't be awaken for unnecessary IRQs.
>>
>> By setting the CPUIDLE_FLAG_TIMER_STOP flag, we can reuse the same code
>> for both the enter() and enter_freeze() callbacks.
>>
>> Signed-off-by: Tomeu Vizoso <[email protected]>
>> Cc: Rafael J. Wysocki <[email protected]>
>>
>> ---
>>
>> v3: * Set CPUIDLE_FLAG_TIMER_STOP to simplify things as suggested by
>> Lorenzo Pieralisi
>> v2: * Disable FIQs also when suspending-to-idle
>> ---
>> arch/arm/mach-tegra/cpuidle-tegra114.c | 13 +++++++++----
>> 1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/mach-tegra/cpuidle-tegra114.c
>> b/arch/arm/mach-tegra/cpuidle-tegra114.c
>> index 155807f..7e59ac0 100644
>> --- a/arch/arm/mach-tegra/cpuidle-tegra114.c
>> +++ b/arch/arm/mach-tegra/cpuidle-tegra114.c
>> @@ -44,16 +44,12 @@ static int tegra114_idle_power_down(struct
>> cpuidle_device *dev,
>> tegra_set_cpu_in_lp2();
>> cpu_pm_enter();
>>
>> - tick_broadcast_enter();
>> -
>> call_firmware_op(prepare_idle);
>>
>> /* Do suspend by ourselves if the firmware does not implement it */
>> if (call_firmware_op(do_idle, 0) == -ENOSYS)
>> cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
>>
>> - tick_broadcast_exit();
>> -
>> cpu_pm_exit();
>> tegra_clear_cpu_in_lp2();
>>
>> @@ -61,6 +57,13 @@ static int tegra114_idle_power_down(struct cpuidle_device
>> *dev,
>>
>> return index;
>> }
>> +
>> +static void tegra114_idle_enter_freeze(struct cpuidle_device *dev,
>> + struct cpuidle_driver *drv,
>> + int index)
>> +{
>> + tegra114_idle_power_down(dev, drv, index);
>> +}
>
> You do not need this function, remove it and update the enter_freeze
> pointer below with tegra114_idle_power_down please.
How so? The callbacks have different signatures.
Regards,
Tomeu
> Thanks,
> Lorenzo
>
>> #endif
>>
>> static struct cpuidle_driver tegra_idle_driver = {
>> @@ -72,8 +75,10 @@ static struct cpuidle_driver tegra_idle_driver = {
>> #ifdef CONFIG_PM_SLEEP
>> [1] = {
>> .enter = tegra114_idle_power_down,
>> + .enter_freeze = tegra114_idle_enter_freeze,
>> .exit_latency = 500,
>> .target_residency = 1000,
>> + .flags = CPUIDLE_FLAG_TIMER_STOP,
>> .power_usage = 0,
>> .name = "powered-down",
>> .desc = "CPU power gated",
>> --
>> 2.4.1
>>
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