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authorHans de Goede <hdegoede@redhat.com>2016-02-23 18:46:25 +0100
committerPhilipp Zabel <p.zabel@pengutronix.de>2016-03-30 15:42:03 +0200
commitc15ddec2ca06076a11195313aa1fce47d2a28c5d (patch)
tree43d14741934dc503d0f6840190b0d5406667bed4 /drivers
parent6c96f05c8bb8bc4177613ef3c23a56b455e75887 (diff)
downloadlinux-c15ddec2ca06076a11195313aa1fce47d2a28c5d.tar.bz2
reset: Share struct reset_control between reset_control_get calls
Now that struct reset_control no longer stores the device pointer for the device calling reset_control_get we can share a single struct reset_control when multiple calls to reset_control_get are made for the same reset line (same id / index). This is a preparation patch for adding support for shared reset lines. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/reset/core.c84
1 files changed, 63 insertions, 21 deletions
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index bdf1763da87a..957750600ff3 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -18,19 +18,23 @@
#include <linux/reset-controller.h>
#include <linux/slab.h>
-static DEFINE_MUTEX(reset_controller_list_mutex);
+static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);
/**
* struct reset_control - a reset control
* @rcdev: a pointer to the reset controller device
* this reset control belongs to
+ * @list: list entry for the rcdev's reset controller list
* @id: ID of the reset controller in the reset
* controller device
+ * @refcnt: Number of gets of this reset_control
*/
struct reset_control {
struct reset_controller_dev *rcdev;
+ struct list_head list;
unsigned int id;
+ unsigned int refcnt;
};
/**
@@ -62,9 +66,11 @@ int reset_controller_register(struct reset_controller_dev *rcdev)
rcdev->of_xlate = of_reset_simple_xlate;
}
- mutex_lock(&reset_controller_list_mutex);
+ INIT_LIST_HEAD(&rcdev->reset_control_head);
+
+ mutex_lock(&reset_list_mutex);
list_add(&rcdev->list, &reset_controller_list);
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return 0;
}
@@ -76,9 +82,9 @@ EXPORT_SYMBOL_GPL(reset_controller_register);
*/
void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
- mutex_lock(&reset_controller_list_mutex);
+ mutex_lock(&reset_list_mutex);
list_del(&rcdev->list);
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_unregister);
@@ -136,6 +142,48 @@ int reset_control_status(struct reset_control *rstc)
}
EXPORT_SYMBOL_GPL(reset_control_status);
+static struct reset_control *__reset_control_get(
+ struct reset_controller_dev *rcdev,
+ unsigned int index)
+{
+ struct reset_control *rstc;
+
+ lockdep_assert_held(&reset_list_mutex);
+
+ list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
+ if (rstc->id == index) {
+ rstc->refcnt++;
+ return rstc;
+ }
+ }
+
+ rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+ if (!rstc)
+ return ERR_PTR(-ENOMEM);
+
+ try_module_get(rcdev->owner);
+
+ rstc->rcdev = rcdev;
+ list_add(&rstc->list, &rcdev->reset_control_head);
+ rstc->id = index;
+ rstc->refcnt = 1;
+
+ return rstc;
+}
+
+static void __reset_control_put(struct reset_control *rstc)
+{
+ lockdep_assert_held(&reset_list_mutex);
+
+ if (--rstc->refcnt)
+ return;
+
+ module_put(rstc->rcdev->owner);
+
+ list_del(&rstc->list);
+ kfree(rstc);
+}
+
struct reset_control *__of_reset_control_get(struct device_node *node,
const char *id, int index)
{
@@ -160,7 +208,7 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
if (ret)
return ERR_PTR(ret);
- mutex_lock(&reset_controller_list_mutex);
+ mutex_lock(&reset_list_mutex);
rcdev = NULL;
list_for_each_entry(r, &reset_controller_list, list) {
if (args.np == r->of_node) {
@@ -171,32 +219,25 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
of_node_put(args.np);
if (!rcdev) {
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return ERR_PTR(-EPROBE_DEFER);
}
if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return ERR_PTR(-EINVAL);
}
rstc_id = rcdev->of_xlate(rcdev, &args);
if (rstc_id < 0) {
- mutex_unlock(&reset_controller_list_mutex);
+ mutex_unlock(&reset_list_mutex);
return ERR_PTR(rstc_id);
}
- try_module_get(rcdev->owner);
- mutex_unlock(&reset_controller_list_mutex);
-
- rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
- if (!rstc) {
- module_put(rcdev->owner);
- return ERR_PTR(-ENOMEM);
- }
+ /* reset_list_mutex also protects the rcdev's reset_control list */
+ rstc = __reset_control_get(rcdev, rstc_id);
- rstc->rcdev = rcdev;
- rstc->id = rstc_id;
+ mutex_unlock(&reset_list_mutex);
return rstc;
}
@@ -212,8 +253,9 @@ void reset_control_put(struct reset_control *rstc)
if (IS_ERR(rstc))
return;
- module_put(rstc->rcdev->owner);
- kfree(rstc);
+ mutex_lock(&reset_list_mutex);
+ __reset_control_put(rstc);
+ mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_put);