[RFC PATCH v1 1/2] drm/rockchip: add a notify event about vblank enable/disable

[Yakir Yang <ykk@rock-chips.com>]

EDP PSR function is interesting in vblank enable or disable event,
so it would be great introduce a way to notify encoder about this
event.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
---
 drivers/gpu/drm/rockchip/Makefile              |  2 +-
 drivers/gpu/drm/rockchip/rockchip_drm_notify.c | 66 ++++++++++++++++++++++++++
 drivers/gpu/drm/rockchip/rockchip_drm_notify.h | 29 +++++++++++
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c    |  5 ++
 4 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/rockchip/rockchip_drm_notify.c
 create mode 100644 drivers/gpu/drm/rockchip/rockchip_drm_notify.h

diff --git a/drivers/gpu/drm/rockchip/Makefile b/drivers/gpu/drm/rockchip/Makefile
index 05d0713..49fee8c 100644
--- a/drivers/gpu/drm/rockchip/Makefile
+++ b/drivers/gpu/drm/rockchip/Makefile
@@ -3,7 +3,7 @@
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
 rockchipdrm-y := rockchip_drm_drv.o rockchip_drm_fb.o \
-		rockchip_drm_gem.o rockchip_drm_vop.o
+		rockchip_drm_gem.o rockchip_drm_vop.o rockchip_drm_notify.o
 rockchipdrm-$(CONFIG_DRM_FBDEV_EMULATION) += rockchip_drm_fbdev.o
 
 obj-$(CONFIG_ROCKCHIP_ANALOGIX_DP) += analogix_dp-rockchip.o
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_notify.c b/drivers/gpu/drm/rockchip/rockchip_drm_notify.c
new file mode 100644
index 0000000..84111d9
--- /dev/null
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_notify.c
@@ -0,0 +1,66 @@
+#include "rockchip_drm_notify.h"
+
+static RAW_NOTIFIER_HEAD(vblank_chain);
+static DEFINE_MUTEX(vblank_lock);
+
+/**
+ * rockchip_drm_vblank_enable - Send Vblank enable event. Will only enable send
+ * Vblank if there are 1 or fewer notifiers.
+ */
+void rockchip_drm_vblank_enable(void)
+{
+	mutex_lock(&vblank_lock);
+	raw_notifier_call_chain(&vblank_chain, VBLANK_ENABLE, NULL);
+	mutex_unlock(&vblank_lock);
+}
+EXPORT_SYMBOL_GPL(rockchip_drm_vblank_enable);
+
+/**
+ * rockchip_drm_vblank_disable - Send VBlank disable event.
+ */
+void rockchip_drm_vblank_disable(void)
+{
+	mutex_lock(&vblank_lock);
+	raw_notifier_call_chain(&vblank_chain, VBLANK_DISABLE, NULL);
+	mutex_unlock(&vblank_lock);
+}
+EXPORT_SYMBOL_GPL(rockchip_drm_vblank_disable);
+
+/**
+ * rockchip_drm_vblank_register_notifier - Add notifier to Vblank notifiers.
+ *
+ * Enable notifiers are called when we enable/disable vblank. This can be done
+ * through rockchip_drm_vblank_enable/disable or when there is more than one
+ * sync notifier. Must call rockchip_drm_vblank_lock before calling this.
+ * @nb The notifier to add
+ */
+int rockchip_drm_vblank_register_notifier(struct notifier_block *nb)
+{
+	int ret = 0;
+
+	if (!nb)
+		return -EINVAL;
+
+	ret = raw_notifier_chain_register(&vblank_chain, nb);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rockchip_drm_vblank_register_notifier);
+
+/**
+ * rockchip_drm_vblank_unregister_notifier - Remove notifier from Vblank
+ * notifiers.
+ *
+ * Must call rockchip_drm_vblank_lock before calling this.
+ * @nb The notifier to remove.
+ */
+int rockchip_drm_vblank_unregister_notifier(struct notifier_block *nb)
+{
+	int ret = 0;
+
+	if (!nb)
+		return -EINVAL;
+
+	ret = raw_notifier_chain_unregister(&vblank_chain, nb);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rockchip_drm_vblank_unregister_notifier);
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_notify.h b/drivers/gpu/drm/rockchip/rockchip_drm_notify.h
new file mode 100644
index 0000000..2f28afa
--- /dev/null
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_notify.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __ROCKCHIP_DRM_NOTIFY_H
+#define __ROCKCHIP_DRM_NOTIFY_H
+
+#include <linux/notifier.h>
+
+enum vblank_enable_op {
+	VBLANK_ENABLE = 0,
+	VBLANK_DISABLE,
+};
+
+void rockchip_drm_vblank_enable(void);
+void rockchip_drm_vblank_disable(void);
+int rockchip_drm_vblank_register_notifier(struct notifier_block *nb);
+int rockchip_drm_vblank_unregister_notifier(struct notifier_block *nb);
+
+#endif /* __ROCKCHIP_DRM_NOTIFY_H */
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 257501f..fb6ce4b 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -35,6 +35,7 @@
 #include "rockchip_drm_gem.h"
 #include "rockchip_drm_fb.h"
 #include "rockchip_drm_vop.h"
+#include "rockchip_drm_notify.h"
 
 #define __REG_SET_RELAXED(x, off, mask, shift, v, write_mask) \
 		vop_mask_write(x, off, mask, shift, v, write_mask, true)
@@ -851,6 +852,8 @@ static int vop_crtc_enable_vblank(struct drm_crtc *crtc)
 
 	spin_unlock_irqrestore(&vop->irq_lock, flags);
 
+	rockchip_drm_vblank_enable();
+
 	return 0;
 }
 
@@ -867,6 +870,8 @@ static void vop_crtc_disable_vblank(struct drm_crtc *crtc)
 	VOP_INTR_SET_TYPE(vop, enable, FS_INTR, 0);
 
 	spin_unlock_irqrestore(&vop->irq_lock, flags);
+
+	rockchip_drm_vblank_disable();
 }
 
 static void vop_crtc_wait_for_update(struct drm_crtc *crtc)
-- 
1.9.1