On Tuesday 07 April 2009, Michael Trimarchi wrote:
> This is a little rework of linux power scheme. TODO:
> - remove recursive call
> - clean-up code
>
> Avoid suspend of a device that is connected with other coprocessor
> like GSM chip.
Well, can you please tell us a bit about the motivation for this work?
I don't like the approach, but I'd like to know what you're trying to achieve.
Rafael
> Signed-off-by: Michael Trimarchi <trimarchi@xxxxxxxxxxxxxxxx>
>
> ---
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 3098c46..2a6ddb3 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -63,6 +63,40 @@ void device_pm_unlock(void)
> mutex_unlock(&dpm_list_mtx);
> }
>
> +int device_set_may_suspend_enable(struct device *dev, void *data)
> +{
> + /* if the device is suspend the subtree is in may_suspend status */
> + if (!dev->power.can_suspend)
> + goto out;
> +
> + dev->power.may_suspend = (unsigned int)data;
> + device_for_each_child(dev, data,
> + device_set_may_suspend_enable);
> +out:
> + return 0;
> +}
> +
> +/**
> + * device_set_suspend_enable - enable/disable device to suspend
> + */
> +int device_set_suspend_enable(struct device *dev, int enable)
> +{
> + mutex_lock(&dpm_list_mtx);
> +
> + if (dev->power.can_suspend == !!enable)
> + goto out;
> +
> + /* Update device children to avoid suspend */
> + device_for_each_child(dev, (void *)!!enable,
> + device_set_may_suspend_enable);
> +
> + dev->power.can_suspend = !!enable;
> +out:
> + mutex_unlock(&dpm_list_mtx);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(device_set_suspend_enable);
> +
> /**
> * device_pm_add - add a device to the list of active devices
> * @dev: Device to be added to the list
> @@ -77,6 +111,13 @@ void device_pm_add(struct device *dev)
> if (dev->parent->power.status >= DPM_SUSPENDING)
> dev_warn(dev, "parent %s should not be sleeping\n",
> dev_name(dev->parent));
> + if (!device_can_suspend(dev->parent)) {
> + mutex_unlock(&dpm_list_mtx);
> + /* if the parent has suspend disable, propagate it
> + * to the new child */
> + device_set_may_suspend_enable(dev, 0);
> + mutex_lock(&dpm_list_mtx);
> + }
> } else if (transition_started) {
> /*
> * We refuse to register parentless devices while a PM
> @@ -120,13 +161,13 @@ static int pm_op(struct device *dev, struct dev_pm_ops *ops,
> switch (state.event) {
> #ifdef CONFIG_SUSPEND
> case PM_EVENT_SUSPEND:
> - if (ops->suspend) {
> + if (device_can_suspend(dev) && ops->suspend) {
> error = ops->suspend(dev);
> suspend_report_result(ops->suspend, error);
> }
> break;
> case PM_EVENT_RESUME:
> - if (ops->resume) {
> + if (device_can_suspend(dev) && ops->resume) {
> error = ops->resume(dev);
> suspend_report_result(ops->resume, error);
> }
> diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
> index 41f51fa..1197b13 100644
> --- a/drivers/base/power/power.h
> +++ b/drivers/base/power/power.h
> @@ -1,6 +1,13 @@
> static inline void device_pm_init(struct device *dev)
> {
> dev->power.status = DPM_ON;
> + dev->power.can_suspend = 1;
> + dev->power.may_suspend = 1;
> +}
> +
> +static inline int device_can_suspend(struct device *dev)
> +{
> + return (dev->power.can_suspend && dev->power.may_suspend);
> }
>
> #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
> index 596aeec..25236aa 100644
> --- a/drivers/base/power/sysfs.c
> +++ b/drivers/base/power/sysfs.c
> @@ -43,6 +43,34 @@
> static const char enabled[] = "enabled";
> static const char disabled[] = "disabled";
>
> +static ssize_t suspend_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + return sprintf(buf, "%s\n", device_can_suspend(dev)
> + ? enabled : disabled);
> +}
> +
> +static ssize_t
> +suspend_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t n)
> +{
> + char *cp;
> + int len = n;
> +
> + cp = memchr(buf, '\n', n);
> + if (cp)
> + len = cp - buf;
> + if (len == sizeof enabled - 1
> + && strncmp(buf, enabled, sizeof enabled - 1) == 0)
> + device_set_suspend_enable(dev, 1);
> + else if (len == sizeof disabled - 1
> + && strncmp(buf, disabled, sizeof disabled - 1) == 0)
> + device_set_suspend_enable(dev, 0);
> + else
> + return -EINVAL;
> + return n;
> +}
> +
> static ssize_t
> wake_show(struct device * dev, struct device_attribute *attr, char * buf)
> {
> @@ -76,10 +104,11 @@ wake_store(struct device * dev, struct device_attribute *attr,
> }
>
> static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
> -
> +static DEVICE_ATTR(suspend, 0644, suspend_show, suspend_store);
>
> static struct attribute * power_attrs[] = {
> &dev_attr_wakeup.attr,
> + &dev_attr_suspend.attr,
> NULL,
> };
> static struct attribute_group pm_attr_group = {
> diff --git a/include/linux/device.h b/include/linux/device.h
> index fdb073b..dc9f242 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -487,6 +487,7 @@ extern struct device *device_find_child(struct device *dev, void *data,
> int (*match)(struct device *dev, void *data));
> extern int device_rename(struct device *dev, char *new_name);
> extern int device_move(struct device *dev, struct device *new_parent);
> +extern int device_set_suspend_enable(struct device *dev, int enable);
>
> /*
> * Root device objects for grouping under /sys/devices
> diff --git a/include/linux/pm.h b/include/linux/pm.h
> index de2e0a8..7586a90 100644
> --- a/include/linux/pm.h
> +++ b/include/linux/pm.h
> @@ -319,6 +319,9 @@ struct dev_pm_info {
> pm_message_t power_state;
> unsigned can_wakeup:1;
> unsigned should_wakeup:1;
> + unsigned can_suspend:1;
> + unsigned may_suspend:1;
> +
> enum dpm_state status; /* Owned by the PM core */
> #ifdef CONFIG_PM_SLEEP
> struct list_head entry;
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