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Message-Id: <1415118568-18771-2-git-send-email-thierry.reding@gmail.com>
Date: Tue, 4 Nov 2014 17:29:28 +0100
From: Thierry Reding <thierry.reding@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Daniel Vetter <daniel.vetter@...ll.ch>,
David Herrmann <dh.herrmann@...il.com>,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [RFC 2/2] drm/panel: Use generic object registry
From: Thierry Reding <treding@...dia.com>
Convert to the new generic object registry and introduce proper object
and module reference counting. This should make panel registration and
removal a lot more robust.
Signed-off-by: Thierry Reding <treding@...dia.com>
---
drivers/gpu/drm/drm_panel.c | 100 ++++++++++++++++++++++++++++++++++----------
include/drm/drm_panel.h | 13 ++++--
2 files changed, 86 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 3dfe3c886502..c1b58bd421a3 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -23,13 +23,11 @@
#include <linux/err.h>
#include <linux/module.h>
+#include <linux/registry.h>
#include <drm/drm_crtc.h>
#include <drm/drm_panel.h>
-static DEFINE_MUTEX(panel_lock);
-static LIST_HEAD(panel_list);
-
/**
* DOC: drm panel
*
@@ -38,6 +36,33 @@ static LIST_HEAD(panel_list);
* drivers.
*/
+/*
+ * DRM panel registry
+ */
+static struct registry panels = {
+ .lock = __MUTEX_INITIALIZER(panels.lock),
+ .list = LIST_HEAD_INIT(panels.list),
+ .owner = THIS_MODULE,
+};
+
+static inline struct drm_panel *to_drm_panel(struct registry_record *record)
+{
+ return container_of(record, struct drm_panel, record);
+}
+
+static void drm_panel_release(struct registry_record *record)
+{
+ struct drm_panel *panel = to_drm_panel(record);
+
+ /*
+ * The .release() callback is optional because drivers may not need
+ * to manually release any resources (e.g. if they've used devm_*()
+ * helper functions).
+ */
+ if (panel->funcs && panel->funcs->release)
+ panel->funcs->release(panel);
+}
+
/**
* drm_panel_init - initialize a panel
* @panel: DRM panel
@@ -47,11 +72,48 @@ static LIST_HEAD(panel_list);
*/
void drm_panel_init(struct drm_panel *panel)
{
- INIT_LIST_HEAD(&panel->list);
+ registry_record_init(&panel->record);
+ panel->record.release = drm_panel_release;
}
EXPORT_SYMBOL(drm_panel_init);
/**
+ * drm_panel_ref - acquire a reference to a panel
+ * @panel: DRM panel
+ *
+ * Increases the reference on a panel and returns a pointer to it.
+ *
+ * Return: A reference to the panel on success or NULL on failure.
+ */
+struct drm_panel *drm_panel_ref(struct drm_panel *panel)
+{
+ if (panel) {
+ struct registry_record *record;
+
+ record = registry_record_ref(&panel->record);
+ if (!record)
+ panel = NULL;
+ }
+
+ return panel;
+}
+EXPORT_SYMBOL(drm_panel_ref);
+
+/**
+ * drm_panel_unref - release a reference to a panel
+ * @panel: DRM panel
+ *
+ * Decreases the reference count on a panel. If the reference count reaches 0
+ * the panel is destroyed.
+ */
+void drm_panel_unref(struct drm_panel *panel)
+{
+ if (panel)
+ registry_record_unref(&panel->record);
+}
+EXPORT_SYMBOL(drm_panel_unref);
+
+/**
* drm_panel_add - add a panel to the global registry
* @panel: panel to add
*
@@ -62,11 +124,10 @@ EXPORT_SYMBOL(drm_panel_init);
*/
int drm_panel_add(struct drm_panel *panel)
{
- mutex_lock(&panel_lock);
- list_add_tail(&panel->list, &panel_list);
- mutex_unlock(&panel_lock);
+ panel->record.owner = panel->dev->driver->owner;
+ panel->record.dev = panel->dev;
- return 0;
+ return registry_add(&panels, &panel->record);
}
EXPORT_SYMBOL(drm_panel_add);
@@ -74,13 +135,12 @@ EXPORT_SYMBOL(drm_panel_add);
* drm_panel_remove - remove a panel from the global registry
* @panel: DRM panel
*
- * Removes a panel from the global registry.
+ * Removes a panel from the global registry. References to the object can
+ * still exist, but drivers won't be able to look the panel up again.
*/
void drm_panel_remove(struct drm_panel *panel)
{
- mutex_lock(&panel_lock);
- list_del_init(&panel->list);
- mutex_unlock(&panel_lock);
+ registry_remove(&panels, &panel->record);
}
EXPORT_SYMBOL(drm_panel_remove);
@@ -132,25 +192,19 @@ EXPORT_SYMBOL(drm_panel_detach);
* @np: device tree node of the panel
*
* Searches the set of registered panels for one that matches the given device
- * tree node. If a matching panel is found, return a pointer to it.
+ * tree node. If a matching panel is found, return a reference to it.
*
* Return: A pointer to the panel registered for the specified device tree
* node or NULL if no panel matching the device tree node can be found.
*/
struct drm_panel *of_drm_find_panel(struct device_node *np)
{
- struct drm_panel *panel;
-
- mutex_lock(&panel_lock);
+ struct registry_record *record;
- list_for_each_entry(panel, &panel_list, list) {
- if (panel->dev->of_node == np) {
- mutex_unlock(&panel_lock);
- return panel;
- }
- }
+ record = registry_find_by_of_node(&panels, np);
+ if (record)
+ return container_of(record, struct drm_panel, record);
- mutex_unlock(&panel_lock);
return NULL;
}
EXPORT_SYMBOL(of_drm_find_panel);
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index b88b4dcd698b..117e221dbc08 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -24,7 +24,8 @@
#ifndef __DRM_PANEL_H__
#define __DRM_PANEL_H__
-#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/registry.h>
struct drm_connector;
struct drm_device;
@@ -32,6 +33,7 @@ struct drm_panel;
/**
* struct drm_panel_funcs - perform operations on a given panel
+ * @release: called when the final reference is dropped
* @disable: disable panel (turn off back light, etc.)
* @unprepare: turn off panel
* @prepare: turn on panel and perform set up
@@ -63,6 +65,7 @@ struct drm_panel;
* the panel. This is the job of the .unprepare() function.
*/
struct drm_panel_funcs {
+ void (*release)(struct drm_panel *panel);
int (*disable)(struct drm_panel *panel);
int (*unprepare)(struct drm_panel *panel);
int (*prepare)(struct drm_panel *panel);
@@ -72,20 +75,20 @@ struct drm_panel_funcs {
/**
* struct drm_panel - DRM panel object
+ * @record: registry record
* @drm: DRM device owning the panel
* @connector: DRM connector that the panel is attached to
* @dev: parent device of the panel
* @funcs: operations that can be performed on the panel
- * @list: panel entry in registry
*/
struct drm_panel {
+ struct registry_record record;
+
struct drm_device *drm;
struct drm_connector *connector;
struct device *dev;
const struct drm_panel_funcs *funcs;
-
- struct list_head list;
};
/**
@@ -180,6 +183,8 @@ static inline int drm_panel_get_modes(struct drm_panel *panel)
}
void drm_panel_init(struct drm_panel *panel);
+struct drm_panel *drm_panel_ref(struct drm_panel *panel);
+void drm_panel_unref(struct drm_panel *panel);
int drm_panel_add(struct drm_panel *panel);
void drm_panel_remove(struct drm_panel *panel);
--
2.1.3
--
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