Re: [PATCH v4] pm_ops: add system quiesce/activate hooks

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Friday, 13 April 2007 15:26, Johannes Berg wrote:
> For powermac, we need to do some things between suspending devices and
> device_power_off, for example setting the decrementer. This patch
> introduces pm_ops.quiesce and pm_ops.activate which will be called instead
> of disabling/enabling irqs so platforms get control over this step.
> 
> If not assigned, these two calls will be assigned with defaults during
> set_pm_ops.
> 
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

I have no objections.  Pavel, what do you think?

Rafael


> ---
>  include/linux/pm.h  |   12 ++++++++++++
>  kernel/power/main.c |   35 ++++++++++++++++++++++++++++++++---
>  2 files changed, 44 insertions(+), 3 deletions(-)
> 
> --- wireless-dev.orig/include/linux/pm.h	2007-04-13 10:09:17.835356880 +0200
> +++ wireless-dev/include/linux/pm.h	2007-04-13 14:57:01.525356880 +0200
> @@ -135,9 +135,19 @@ typedef int __bitwise suspend_disk_metho
>   * @prepare: Prepare the platform for the given suspend state. Can return a
>   *	negative error code if necessary.
>   *
> + * @quiesce: This callback is called after devices are suspended but before
> + *	they are powered down. If assigned, this callback must at least turn
> + *	off local IRQs. If left unassigned, a default callback that does
> + *	nothing but turn off local IRQs is assigned during pm_set_ops().
> + *
>   * @enter: Enter the given suspend state, must be assigned. Can return a
>   *	negative error code if necessary.
>   *
> + * @activate: This callback is called after devices are powered up but
> + *	before they resume. If assigned, this callback must at least turn
> + *	on local IRQs. If left unassigned, a default callback that does
> + *	nothing but turn on local IRQs is assigned during pm_set_ops().
> + *
>   * @finish: Called when the system has left the given state and all devices
>   *	are resumed. The return value is ignored.
>   *
> @@ -155,7 +165,9 @@ typedef int __bitwise suspend_disk_metho
>  struct pm_ops {
>  	int (*valid)(suspend_state_t state);
>  	int (*prepare)(suspend_state_t state);
> +	void (*quiesce)(suspend_state_t state);
>  	int (*enter)(suspend_state_t state);
> +	void (*activate)(suspend_state_t state);
>  	int (*finish)(suspend_state_t state);
>  	suspend_disk_method_t pm_disk_mode;
>  };
> --- wireless-dev.orig/kernel/power/main.c	2007-04-13 10:09:17.835356880 +0200
> +++ wireless-dev/kernel/power/main.c	2007-04-13 14:53:44.975356880 +0200
> @@ -33,6 +33,28 @@ struct pm_ops *pm_ops;
>  suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
>  
>  /**
> + * pm_default_quiesce - default quiesce callback
> + *
> + * pm_ops drivers that need to do nothing but disable IRQs
> + * leave .quiesce unassigned and pm_set_ops() assigns this.
> + */
> +static void pm_default_quiesce(suspend_state_t state)
> +{
> +	local_irq_disable();
> +}
> +
> +/**
> + * pm_default_activate - default activate callback
> + *
> + * pm_ops drivers that need to do nothing but enable IRQs
> + * leave .activate unassigned and pm_set_ops assigns this.
> + */
> +static void pm_default_activate(suspend_state_t state)
> +{
> +	local_irq_enable();
> +}
> +
> +/**
>   *	pm_set_ops - Set the global power method table. 
>   *	@ops:	Pointer to ops structure.
>   */
> @@ -45,6 +67,12 @@ void pm_set_ops(struct pm_ops * ops)
>  		pm_disk_mode = ops->pm_disk_mode;
>  	} else
>  		pm_disk_mode = PM_DISK_SHUTDOWN;
> +
> +	if (!ops->quiesce)
> +		ops->quiesce = pm_default_quiesce;
> +	if (!ops->activate)
> +		ops->activate = pm_default_activate;
> +
>  	mutex_unlock(&pm_mutex);
>  }
>  
> @@ -132,9 +160,9 @@ static int suspend_prepare(suspend_state
>  int suspend_enter(suspend_state_t state)
>  {
>  	int error = 0;
> -	unsigned long flags;
>  
> -	local_irq_save(flags);
> +	pm_ops->quiesce(state);
> +	BUG_ON(!irqs_disabled());
>  
>  	if ((error = device_power_down(PMSG_SUSPEND))) {
>  		printk(KERN_ERR "Some devices failed to power down\n");
> @@ -143,7 +171,8 @@ int suspend_enter(suspend_state_t state)
>  	error = pm_ops->enter(state);
>  	device_power_up();
>   Done:
> -	local_irq_restore(flags);
> +	pm_ops->activate(state);
> +	BUG_ON(irqs_disabled());
>  	return error;
>  }