drm/bridge: make bridge registration independent of drm flow

Currently, third party bridge drivers(ptn3460) are dependent
on the corresponding encoder driver init, since bridge driver
needs a drm_device pointer to finish drm initializations.
The encoder driver passes the drm_device pointer to the
bridge driver. Because of this dependency, third party drivers
like ptn3460 doesn't adhere to the driver model.

In this patch, we reframe the bridge registration framework
so that bridge initialization is split into 2 steps, and
bridge registration happens independent of drm flow:
--Step 1: gather all the bridge settings independent of drm and
	  add the bridge onto a global list of bridges.
--Step 2: when the encoder driver is probed, call drm_bridge_attach
	  for the corresponding bridge so that the bridge receives
	  drm_device pointer and continues with connector and other
	  drm initializations.

The old set of bridge helpers are removed, and a set of new helpers
are added to accomplish the 2 step initialization.

The bridge devices register themselves onto global list of bridges
when they get probed by calling "drm_bridge_add".

The parent encoder driver waits till the bridge is available
in the lookup table(by calling "of_drm_find_bridge") and then
continues with its initialization.

The encoder driver should also call "drm_bridge_attach" to pass
on the drm_device to the bridge object.

drm_bridge_attach inturn calls "bridge->funcs->attach" so that
bridge can continue with drm related initializations.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Tested-by: Rahul Sharma <rahul.sharma@samsung.com>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Tested-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>

9 files changed, 112 insertions, 106 deletions

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index cf0eed8208b5..2c239b99de64 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -14,7 +14,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_info.o drm_debugfs.o drm_encoder_slave.o \
 		drm_trace_points.o drm_global.o drm_prime.o \
 		drm_rect.o drm_vma_manager.o drm_flip_work.o \
-		drm_modeset_lock.o drm_atomic.o
+		drm_modeset_lock.o drm_atomic.o drm_bridge.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
diff --git a/drivers/gpu/drm/bridge/ptn3460.c b/drivers/gpu/drm/bridge/ptn3460.c
index a2ddc8d73c6a..4a818c1b62e0 100644
--- a/drivers/gpu/drm/bridge/ptn3460.c
+++ b/drivers/gpu/drm/bridge/ptn3460.c
@@ -176,24 +176,11 @@ static void ptn3460_post_disable(struct drm_bridge *bridge)
 {
 }
 
-static void ptn3460_bridge_destroy(struct drm_bridge *bridge)
-{
-	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
-
-	drm_bridge_cleanup(bridge);
-	if (gpio_is_valid(ptn_bridge->gpio_pd_n))
-		gpio_free(ptn_bridge->gpio_pd_n);
-	if (gpio_is_valid(ptn_bridge->gpio_rst_n))
-		gpio_free(ptn_bridge->gpio_rst_n);
-	/* Nothing else to free, we've got devm allocated memory */
-}
-
 static struct drm_bridge_funcs ptn3460_bridge_funcs = {
 	.pre_enable = ptn3460_pre_enable,
 	.enable = ptn3460_enable,
 	.disable = ptn3460_disable,
 	.post_disable = ptn3460_post_disable,
-	.destroy = ptn3460_bridge_destroy,
 };
 
 static int ptn3460_get_modes(struct drm_connector *connector)
@@ -314,7 +301,7 @@ int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
 	}
 
 	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
-	ret = drm_bridge_init(dev, &ptn_bridge->bridge);
+	ret = drm_bridge_attach(dev, &ptn_bridge->bridge);
 	if (ret) {
 		DRM_ERROR("Failed to initialize bridge with drm\n");
 		goto err;
@@ -343,3 +330,15 @@ err:
 	return ret;
 }
 EXPORT_SYMBOL(ptn3460_init);
+
+void ptn3460_destroy(struct drm_bridge *bridge)
+{
+	struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
+
+	if (gpio_is_valid(ptn_bridge->gpio_pd_n))
+		gpio_free(ptn_bridge->gpio_pd_n);
+	if (gpio_is_valid(ptn_bridge->gpio_rst_n))
+		gpio_free(ptn_bridge->gpio_rst_n);
+	/* Nothing else to free, we've got devm allocated memory */
+}
+EXPORT_SYMBOL(ptn3460_destroy);
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
new file mode 100644
index 000000000000..d1187e571c6d
--- /dev/null
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+
+#include <drm/drm_crtc.h>
+
+#include "drm/drmP.h"
+
+static DEFINE_MUTEX(bridge_lock);
+static LIST_HEAD(bridge_list);
+
+int drm_bridge_add(struct drm_bridge *bridge)
+{
+	mutex_lock(&bridge_lock);
+	list_add_tail(&bridge->list, &bridge_list);
+	mutex_unlock(&bridge_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_bridge_add);
+
+void drm_bridge_remove(struct drm_bridge *bridge)
+{
+	mutex_lock(&bridge_lock);
+	list_del_init(&bridge->list);
+	mutex_unlock(&bridge_lock);
+}
+EXPORT_SYMBOL(drm_bridge_remove);
+
+extern int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge)
+{
+	if (!dev || !bridge)
+		return -EINVAL;
+
+	if (bridge->dev)
+		return -EBUSY;
+
+	bridge->dev = dev;
+
+	if (bridge->funcs->attach)
+		return bridge->funcs->attach(bridge);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_bridge_attach);
+
+#ifdef CONFIG_OF
+struct drm_bridge *of_drm_find_bridge(struct device_node *np)
+{
+	struct drm_bridge *bridge;
+
+	mutex_lock(&bridge_lock);
+
+	list_for_each_entry(bridge, &bridge_list, list) {
+		if (bridge->of_node == np) {
+			mutex_unlock(&bridge_lock);
+			return bridge;
+		}
+	}
+
+	mutex_unlock(&bridge_lock);
+	return NULL;
+}
+EXPORT_SYMBOL(of_drm_find_bridge);
+#endif
+
+MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
+MODULE_DESCRIPTION("DRM bridge infrastructure");
+MODULE_LICENSE("GPL and additional rights");
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 7936c5c2314c..0e4ec700b0a6 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1066,58 +1066,6 @@ void drm_connector_unplug_all(struct drm_device *dev)
 EXPORT_SYMBOL(drm_connector_unplug_all);
 
 /**
- * drm_bridge_init - initialize a drm transcoder/bridge
- * @dev: drm device
- * @bridge: transcoder/bridge to set up
- *
- * Initialises a preallocated bridge. Bridges should be
- * subclassed as part of driver connector objects.
- *
- * Returns:
- * Zero on success, error code on failure.
- */
-int drm_bridge_init(struct drm_device *dev, struct drm_bridge *bridge)
-{
-	int ret;
-
-	drm_modeset_lock_all(dev);
-
-	ret = drm_mode_object_get(dev, &bridge->base, DRM_MODE_OBJECT_BRIDGE);
-	if (ret)
-		goto out;
-
-	bridge->dev = dev;
-
-	list_add_tail(&bridge->head, &dev->mode_config.bridge_list);
-	dev->mode_config.num_bridge++;
-
- out:
-	drm_modeset_unlock_all(dev);
-	return ret;
-}
-EXPORT_SYMBOL(drm_bridge_init);
-
-/**
- * drm_bridge_cleanup - cleans up an initialised bridge
- * @bridge: bridge to cleanup
- *
- * Cleans up the bridge but doesn't free the object.
- */
-void drm_bridge_cleanup(struct drm_bridge *bridge)
-{
-	struct drm_device *dev = bridge->dev;
-
-	drm_modeset_lock_all(dev);
-	drm_mode_object_put(dev, &bridge->base);
-	list_del(&bridge->head);
-	dev->mode_config.num_bridge--;
-	drm_modeset_unlock_all(dev);
-
-	memset(bridge, 0, sizeof(*bridge));
-}
-EXPORT_SYMBOL(drm_bridge_cleanup);
-
-/**
  * drm_encoder_init - Init a preallocated encoder
  * @dev: drm device
  * @encoder: the encoder to init
@@ -1712,7 +1660,6 @@ static int drm_mode_group_init(struct drm_device *dev, struct drm_mode_group *gr
 	total_objects += dev->mode_config.num_crtc;
 	total_objects += dev->mode_config.num_connector;
 	total_objects += dev->mode_config.num_encoder;
-	total_objects += dev->mode_config.num_bridge;
 
 	group->id_list = kcalloc(total_objects, sizeof(uint32_t), GFP_KERNEL);
 	if (!group->id_list)
@@ -1721,7 +1668,6 @@ static int drm_mode_group_init(struct drm_device *dev, struct drm_mode_group *gr
 	group->num_crtcs = 0;
 	group->num_connectors = 0;
 	group->num_encoders = 0;
-	group->num_bridges = 0;
 	return 0;
 }
 
@@ -1741,7 +1687,6 @@ int drm_mode_group_init_legacy_group(struct drm_device *dev,
 	struct drm_crtc *crtc;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
-	struct drm_bridge *bridge;
 	int ret;
 
 	ret = drm_mode_group_init(dev, group);
@@ -1759,11 +1704,6 @@ int drm_mode_group_init_legacy_group(struct drm_device *dev,
 		group->id_list[group->num_crtcs + group->num_encoders +
 			       group->num_connectors++] = connector->base.id;
 
-	list_for_each_entry(bridge, &dev->mode_config.bridge_list, head)
-		group->id_list[group->num_crtcs + group->num_encoders +
-			       group->num_connectors + group->num_bridges++] =
-					bridge->base.id;
-
 	return 0;
 }
 EXPORT_SYMBOL(drm_mode_group_init_legacy_group);
@@ -5440,7 +5380,6 @@ void drm_mode_config_init(struct drm_device *dev)
 	INIT_LIST_HEAD(&dev->mode_config.fb_list);
 	INIT_LIST_HEAD(&dev->mode_config.crtc_list);
 	INIT_LIST_HEAD(&dev->mode_config.connector_list);
-	INIT_LIST_HEAD(&dev->mode_config.bridge_list);
 	INIT_LIST_HEAD(&dev->mode_config.encoder_list);
 	INIT_LIST_HEAD(&dev->mode_config.property_list);
 	INIT_LIST_HEAD(&dev->mode_config.property_blob_list);
@@ -5480,7 +5419,6 @@ void drm_mode_config_cleanup(struct drm_device *dev)
 	struct drm_connector *connector, *ot;
 	struct drm_crtc *crtc, *ct;
 	struct drm_encoder *encoder, *enct;
-	struct drm_bridge *bridge, *brt;
 	struct drm_framebuffer *fb, *fbt;
 	struct drm_property *property, *pt;
 	struct drm_property_blob *blob, *bt;
@@ -5491,11 +5429,6 @@ void drm_mode_config_cleanup(struct drm_device *dev)
 		encoder->funcs->destroy(encoder);
 	}
 
-	list_for_each_entry_safe(bridge, brt,
-				 &dev->mode_config.bridge_list, head) {
-		bridge->funcs->destroy(bridge);
-	}
-
 	list_for_each_entry_safe(connector, ot,
 				 &dev->mode_config.connector_list, head) {
 		connector->funcs->destroy(connector);
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
index 062c68725376..95f7b8d0f3ef 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
@@ -247,9 +247,9 @@ int hdmi_modeset_init(struct hdmi *hdmi,
 	return 0;
 
 fail:
-	/* bridge/connector are normally destroyed by drm: */
+	/* bridge is normally destroyed by drm: */
 	if (hdmi->bridge) {
-		hdmi->bridge->funcs->destroy(hdmi->bridge);
+		hdmi_bridge_destroy(hdmi->bridge);
 		hdmi->bridge = NULL;
 	}
 	if (hdmi->connector) {
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.h b/drivers/gpu/drm/msm/hdmi/hdmi.h
index 43e654f751b7..4d4cad42a776 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.h
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.h
@@ -146,6 +146,7 @@ void hdmi_audio_set_sample_rate(struct hdmi *hdmi, int rate);
  */
 
 struct drm_bridge *hdmi_bridge_init(struct hdmi *hdmi);
+void hdmi_bridge_destroy(struct drm_bridge *bridge);
 
 /*
  * hdmi connector:
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index 52ed2b53b246..d6f8d5818e18 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -23,10 +23,9 @@ struct hdmi_bridge {
 };
 #define to_hdmi_bridge(x) container_of(x, struct hdmi_bridge, base)
 
-static void hdmi_bridge_destroy(struct drm_bridge *bridge)
+void hdmi_bridge_destroy(struct drm_bridge *bridge)
 {
 	struct hdmi_bridge *hdmi_bridge = to_hdmi_bridge(bridge);
-	drm_bridge_cleanup(bridge);
 	kfree(hdmi_bridge);
 }
 
@@ -200,7 +199,6 @@ static const struct drm_bridge_funcs hdmi_bridge_funcs = {
 		.disable = hdmi_bridge_disable,
 		.post_disable = hdmi_bridge_post_disable,
 		.mode_set = hdmi_bridge_mode_set,
-		.destroy = hdmi_bridge_destroy,
 };
 
 
@@ -222,7 +220,7 @@ struct drm_bridge *hdmi_bridge_init(struct hdmi *hdmi)
 	bridge = &hdmi_bridge->base;
 	bridge->funcs = &hdmi_bridge_funcs;
 
-	drm_bridge_init(hdmi->dev, bridge);
+	drm_bridge_attach(hdmi->dev, bridge);
 
 	return bridge;
 
diff --git a/drivers/gpu/drm/sti/sti_hda.c b/drivers/gpu/drm/sti/sti_hda.c
index 6cf145de9b41..a9bbb081ecad 100644
--- a/drivers/gpu/drm/sti/sti_hda.c
+++ b/drivers/gpu/drm/sti/sti_hda.c
@@ -508,19 +508,12 @@ static void sti_hda_bridge_nope(struct drm_bridge *bridge)
 	/* do nothing */
 }
 
-static void sti_hda_brigde_destroy(struct drm_bridge *bridge)
-{
-	drm_bridge_cleanup(bridge);
-	kfree(bridge);
-}
-
 static const struct drm_bridge_funcs sti_hda_bridge_funcs = {
 	.pre_enable = sti_hda_pre_enable,
 	.enable = sti_hda_bridge_nope,
 	.disable = sti_hda_disable,
 	.post_disable = sti_hda_bridge_nope,
 	.mode_set = sti_hda_set_mode,
-	.destroy = sti_hda_brigde_destroy,
 };
 
 static int sti_hda_connector_get_modes(struct drm_connector *connector)
@@ -665,7 +658,7 @@ static int sti_hda_bind(struct device *dev, struct device *master, void *data)
 
 	bridge->driver_private = hda;
 	bridge->funcs = &sti_hda_bridge_funcs;
-	drm_bridge_init(drm_dev, bridge);
+	drm_bridge_attach(drm_dev, bridge);
 
 	encoder->bridge = bridge;
 	connector->encoder = encoder;
@@ -694,7 +687,6 @@ static int sti_hda_bind(struct device *dev, struct device *master, void *data)
 err_sysfs:
 	drm_connector_unregister(drm_connector);
 err_connector:
-	drm_bridge_cleanup(bridge);
 	drm_connector_cleanup(drm_connector);
 	return -EINVAL;
 }
diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c
index 74e943e655d1..e840ca5de401 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.c
+++ b/drivers/gpu/drm/sti/sti_hdmi.c
@@ -463,19 +463,12 @@ static void sti_hdmi_bridge_nope(struct drm_bridge *bridge)
 	/* do nothing */
 }
 
-static void sti_hdmi_brigde_destroy(struct drm_bridge *bridge)
-{
-	drm_bridge_cleanup(bridge);
-	kfree(bridge);
-}
-
 static const struct drm_bridge_funcs sti_hdmi_bridge_funcs = {
 	.pre_enable = sti_hdmi_pre_enable,
 	.enable = sti_hdmi_bridge_nope,
 	.disable = sti_hdmi_disable,
 	.post_disable = sti_hdmi_bridge_nope,
 	.mode_set = sti_hdmi_set_mode,
-	.destroy = sti_hdmi_brigde_destroy,
 };
 
 static int sti_hdmi_connector_get_modes(struct drm_connector *connector)
@@ -636,7 +629,7 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
 
 	bridge->driver_private = hdmi;
 	bridge->funcs = &sti_hdmi_bridge_funcs;
-	drm_bridge_init(drm_dev, bridge);
+	drm_bridge_attach(drm_dev, bridge);
 
 	encoder->bridge = bridge;
 	connector->encoder = encoder;
@@ -668,7 +661,6 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
 err_sysfs:
 	drm_connector_unregister(drm_connector);
 err_connector:
-	drm_bridge_cleanup(bridge);
 	drm_connector_cleanup(drm_connector);
 err_adapt:
 	put_device(&hdmi->ddc_adapt->dev);