From 13b2c4a0c3b1cd37ee6bcfbb5b6e2b94e9a75364 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: Mon, 27 Jul 2015 18:03:56 +0300
Subject: PM / QoS: Make it possible to expose device latency tolerance to
userspace
Typically when a device is created the bus core it belongs to (for example
PCI) does not know if the device supports things like latency tolerance.
This is left to the driver that binds to the device in question. However,
at that time the device has already been created and there is no way to set
its dev->power.set_latency_tolerance anymore.
So follow what has been done for other PM QoS attributes as well and allow
drivers to expose and hide latency tolerance from userspace, if the device
supports it.
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
include/linux/pm_qos.h | 5 +++++
1 file changed, 5 insertions(+)
(limited to 'include/linux')
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 7b3ae0cffc05..0f65d36c2a75 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -161,6 +161,8 @@ void dev_pm_qos_hide_flags(struct device *dev);
int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set);
s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev);
int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val);
+int dev_pm_qos_expose_latency_tolerance(struct device *dev);
+void dev_pm_qos_hide_latency_tolerance(struct device *dev);
static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev)
{
@@ -229,6 +231,9 @@ static inline s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
{ return PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; }
static inline int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
{ return 0; }
+static inline int dev_pm_qos_expose_latency_tolerance(struct device *dev)
+ { return 0; }
+static inline void dev_pm_qos_hide_latency_tolerance(struct device *dev) {}
static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; }
static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; }
--
cgit v1.2.3
From 2e0fed7f7cdc41679e209c5636ad7537dc6210a9 Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Mon, 27 Jul 2015 18:03:59 +0300
Subject: klist: implement klist_prev()
klist_prev() gets the previous element in the list. It is useful to traverse
through the list in reverse order, for example, to provide LIFO (last in first
out) variant of access.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
include/linux/klist.h | 1 +
lib/klist.c | 41 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+)
(limited to 'include/linux')
diff --git a/include/linux/klist.h b/include/linux/klist.h
index 61e5b723ae73..953f283f8451 100644
--- a/include/linux/klist.h
+++ b/include/linux/klist.h
@@ -63,6 +63,7 @@ extern void klist_iter_init(struct klist *k, struct klist_iter *i);
extern void klist_iter_init_node(struct klist *k, struct klist_iter *i,
struct klist_node *n);
extern void klist_iter_exit(struct klist_iter *i);
+extern struct klist_node *klist_prev(struct klist_iter *i);
extern struct klist_node *klist_next(struct klist_iter *i);
#endif
diff --git a/lib/klist.c b/lib/klist.c
index 89b485a2a58d..d74cf7a29afd 100644
--- a/lib/klist.c
+++ b/lib/klist.c
@@ -323,6 +323,47 @@ static struct klist_node *to_klist_node(struct list_head *n)
return container_of(n, struct klist_node, n_node);
}
+/**
+ * klist_prev - Ante up prev node in list.
+ * @i: Iterator structure.
+ *
+ * First grab list lock. Decrement the reference count of the previous
+ * node, if there was one. Grab the prev node, increment its reference
+ * count, drop the lock, and return that prev node.
+ */
+struct klist_node *klist_prev(struct klist_iter *i)
+{
+ void (*put)(struct klist_node *) = i->i_klist->put;
+ struct klist_node *last = i->i_cur;
+ struct klist_node *prev;
+
+ spin_lock(&i->i_klist->k_lock);
+
+ if (last) {
+ prev = to_klist_node(last->n_node.prev);
+ if (!klist_dec_and_del(last))
+ put = NULL;
+ } else
+ prev = to_klist_node(i->i_klist->k_list.prev);
+
+ i->i_cur = NULL;
+ while (prev != to_klist_node(&i->i_klist->k_list)) {
+ if (likely(!knode_dead(prev))) {
+ kref_get(&prev->n_ref);
+ i->i_cur = prev;
+ break;
+ }
+ prev = to_klist_node(prev->n_node.prev);
+ }
+
+ spin_unlock(&i->i_klist->k_lock);
+
+ if (put && last)
+ put(last);
+ return i->i_cur;
+}
+EXPORT_SYMBOL_GPL(klist_prev);
+
/**
* klist_next - Ante up next node in list.
* @i: Iterator structure.
--
cgit v1.2.3
From 3d060aeb72113cda0acf906bfe26914fc689506a Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Mon, 27 Jul 2015 18:04:00 +0300
Subject: driver core: implement device_for_each_child_reverse()
The new function device_for_each_child_reverse() is helpful to traverse the
registered devices in a reversed order, e.g. in the case when an operation on
each device should be done first on the last added device, then on one before
last and so on.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/base/core.c | 43 +++++++++++++++++++++++++++++++++++++++++++
include/linux/device.h | 2 ++
2 files changed, 45 insertions(+)
(limited to 'include/linux')
diff --git a/drivers/base/core.c b/drivers/base/core.c
index dafae6d2f7ac..7d6279554afc 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1252,6 +1252,19 @@ void device_unregister(struct device *dev)
}
EXPORT_SYMBOL_GPL(device_unregister);
+static struct device *prev_device(struct klist_iter *i)
+{
+ struct klist_node *n = klist_prev(i);
+ struct device *dev = NULL;
+ struct device_private *p;
+
+ if (n) {
+ p = to_device_private_parent(n);
+ dev = p->device;
+ }
+ return dev;
+}
+
static struct device *next_device(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
@@ -1340,6 +1353,36 @@ int device_for_each_child(struct device *parent, void *data,
}
EXPORT_SYMBOL_GPL(device_for_each_child);
+/**
+ * device_for_each_child_reverse - device child iterator in reversed order.
+ * @parent: parent struct device.
+ * @fn: function to be called for each device.
+ * @data: data for the callback.
+ *
+ * Iterate over @parent's child devices, and call @fn for each,
+ * passing it @data.
+ *
+ * We check the return of @fn each time. If it returns anything
+ * other than 0, we break out and return that value.
+ */
+int device_for_each_child_reverse(struct device *parent, void *data,
+ int (*fn)(struct device *dev, void *data))
+{
+ struct klist_iter i;
+ struct device *child;
+ int error = 0;
+
+ if (!parent->p)
+ return 0;
+
+ klist_iter_init(&parent->p->klist_children, &i);
+ while ((child = prev_device(&i)) && !error)
+ error = fn(child, data);
+ klist_iter_exit(&i);
+ return error;
+}
+EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
+
/**
* device_find_child - device iterator for locating a particular device.
* @parent: parent struct device
diff --git a/include/linux/device.h b/include/linux/device.h
index 5a31bf3a4024..af6fbc35d8a6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -958,6 +958,8 @@ extern int __must_check device_add(struct device *dev);
extern void device_del(struct device *dev);
extern int device_for_each_child(struct device *dev, void *data,
int (*fn)(struct device *dev, void *data));
+extern int device_for_each_child_reverse(struct device *dev, void *data,
+ int (*fn)(struct device *dev, void *data));
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, const char *new_name);
--
cgit v1.2.3