1 files changed, 382 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
new file mode 100644
index 000000000..1638bfe96
--- /dev/null
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -0,0 +1,382 @@
+/*
+ * 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 <linux/mutex.h>
+
+#include <drm/drm_bridge.h>
+#include <drm/drm_encoder.h>
+
+#include "drm_crtc_internal.h"
+
+/**
+ * DOC: overview
+ *
+ * &struct drm_bridge represents a device that hangs on to an encoder. These are
+ * handy when a regular &drm_encoder entity isn't enough to represent the entire
+ * encoder chain.
+ *
+ * A bridge is always attached to a single &drm_encoder at a time, but can be
+ * either connected to it directly, or through an intermediate bridge::
+ *
+ *     encoder ---> bridge B ---> bridge A
+ *
+ * Here, the output of the encoder feeds to bridge B, and that furthers feeds to
+ * bridge A.
+ *
+ * The driver using the bridge is responsible to make the associations between
+ * the encoder and bridges. Once these links are made, the bridges will
+ * participate along with encoder functions to perform mode_set/enable/disable
+ * through the ops provided in &drm_bridge_funcs.
+ *
+ * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,
+ * CRTCs, encoders or connectors and hence are not visible to userspace. They
+ * just provide additional hooks to get the desired output at the end of the
+ * encoder chain.
+ *
+ * Bridges can also be chained up using the &drm_bridge.next pointer.
+ *
+ * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
+ */
+
+static DEFINE_MUTEX(bridge_lock);
+static LIST_HEAD(bridge_list);
+
+/**
+ * drm_bridge_add - add the given bridge to the global bridge list
+ *
+ * @bridge: bridge control structure
+ */
+void drm_bridge_add(struct drm_bridge *bridge)
+{
+	mutex_lock(&bridge_lock);
+	list_add_tail(&bridge->list, &bridge_list);
+	mutex_unlock(&bridge_lock);
+}
+EXPORT_SYMBOL(drm_bridge_add);
+
+/**
+ * drm_bridge_remove - remove the given bridge from the global bridge list
+ *
+ * @bridge: bridge control structure
+ */
+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);
+
+/**
+ * drm_bridge_attach - attach the bridge to an encoder's chain
+ *
+ * @encoder: DRM encoder
+ * @bridge: bridge to attach
+ * @previous: previous bridge in the chain (optional)
+ *
+ * Called by a kms driver to link the bridge to an encoder's chain. The previous
+ * argument specifies the previous bridge in the chain. If NULL, the bridge is
+ * linked directly at the encoder's output. Otherwise it is linked at the
+ * previous bridge's output.
+ *
+ * If non-NULL the previous bridge must be already attached by a call to this
+ * function.
+ *
+ * RETURNS:
+ * Zero on success, error code on failure
+ */
+int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
+		      struct drm_bridge *previous)
+{
+	int ret;
+
+	if (!encoder || !bridge)
+		return -EINVAL;
+
+	if (previous && (!previous->dev || previous->encoder != encoder))
+		return -EINVAL;
+
+	if (bridge->dev)
+		return -EBUSY;
+
+	bridge->dev = encoder->dev;
+	bridge->encoder = encoder;
+
+	if (bridge->funcs->attach) {
+		ret = bridge->funcs->attach(bridge);
+		if (ret < 0) {
+			bridge->dev = NULL;
+			bridge->encoder = NULL;
+			return ret;
+		}
+	}
+
+	if (previous)
+		previous->next = bridge;
+	else
+		encoder->bridge = bridge;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_bridge_attach);
+
+void drm_bridge_detach(struct drm_bridge *bridge)
+{
+	if (WARN_ON(!bridge))
+		return;
+
+	if (WARN_ON(!bridge->dev))
+		return;
+
+	if (bridge->funcs->detach)
+		bridge->funcs->detach(bridge);
+
+	bridge->dev = NULL;
+}
+
+/**
+ * DOC: bridge callbacks
+ *
+ * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
+ * internals (atomic and CRTC helpers) use the helpers defined in drm_bridge.c
+ * These helpers call a specific &drm_bridge_funcs op for all the bridges
+ * during encoder configuration.
+ *
+ * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
+ */
+
+/**
+ * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the
+ *			   encoder chain
+ * @bridge: bridge control structure
+ * @mode: desired mode to be set for the bridge
+ * @adjusted_mode: updated mode that works for this bridge
+ *
+ * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
+ * encoder chain, starting from the first bridge to the last.
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ *
+ * RETURNS:
+ * true on success, false on failure
+ */
+bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
+			const struct drm_display_mode *mode,
+			struct drm_display_mode *adjusted_mode)
+{
+	bool ret = true;
+
+	if (!bridge)
+		return true;
+
+	if (bridge->funcs->mode_fixup)
+		ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
+
+	ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_bridge_mode_fixup);
+
+/**
+ * drm_bridge_mode_valid - validate the mode against all bridges in the
+ * 			   encoder chain.
+ * @bridge: bridge control structure
+ * @mode: desired mode to be validated
+ *
+ * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
+ * chain, starting from the first bridge to the last. If at least one bridge
+ * does not accept the mode the function returns the error code.
+ *
+ * Note: the bridge passed should be the one closest to the encoder.
+ *
+ * RETURNS:
+ * MODE_OK on success, drm_mode_status Enum error code on failure
+ */
+enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
+					   const struct drm_display_mode *mode)
+{
+	enum drm_mode_status ret = MODE_OK;
+
+	if (!bridge)
+		return ret;
+
+	if (bridge->funcs->mode_valid)
+		ret = bridge->funcs->mode_valid(bridge, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	return drm_bridge_mode_valid(bridge->next, mode);
+}
+EXPORT_SYMBOL(drm_bridge_mode_valid);
+
+/**
+ * drm_bridge_disable - disables all bridges in the encoder chain
+ * @bridge: bridge control structure
+ *
+ * Calls &drm_bridge_funcs.disable op for all the bridges in the encoder
+ * chain, starting from the last bridge to the first. These are called before
+ * calling the encoder's prepare op.
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_bridge_disable(struct drm_bridge *bridge)
+{
+	if (!bridge)
+		return;
+
+	drm_bridge_disable(bridge->next);
+
+	if (bridge->funcs->disable)
+		bridge->funcs->disable(bridge);
+}
+EXPORT_SYMBOL(drm_bridge_disable);
+
+/**
+ * drm_bridge_post_disable - cleans up after disabling all bridges in the encoder chain
+ * @bridge: bridge control structure
+ *
+ * Calls &drm_bridge_funcs.post_disable op for all the bridges in the
+ * encoder chain, starting from the first bridge to the last. These are called
+ * after completing the encoder's prepare op.
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_bridge_post_disable(struct drm_bridge *bridge)
+{
+	if (!bridge)
+		return;
+
+	if (bridge->funcs->post_disable)
+		bridge->funcs->post_disable(bridge);
+
+	drm_bridge_post_disable(bridge->next);
+}
+EXPORT_SYMBOL(drm_bridge_post_disable);
+
+/**
+ * drm_bridge_mode_set - set proposed mode for all bridges in the
+ *			 encoder chain
+ * @bridge: bridge control structure
+ * @mode: desired mode to be set for the bridge
+ * @adjusted_mode: updated mode that works for this bridge
+ *
+ * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
+ * encoder chain, starting from the first bridge to the last.
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_bridge_mode_set(struct drm_bridge *bridge,
+			struct drm_display_mode *mode,
+			struct drm_display_mode *adjusted_mode)
+{
+	if (!bridge)
+		return;
+
+	if (bridge->funcs->mode_set)
+		bridge->funcs->mode_set(bridge, mode, adjusted_mode);
+
+	drm_bridge_mode_set(bridge->next, mode, adjusted_mode);
+}
+EXPORT_SYMBOL(drm_bridge_mode_set);
+
+/**
+ * drm_bridge_pre_enable - prepares for enabling all
+ *			   bridges in the encoder chain
+ * @bridge: bridge control structure
+ *
+ * Calls &drm_bridge_funcs.pre_enable op for all the bridges in the encoder
+ * chain, starting from the last bridge to the first. These are called
+ * before calling the encoder's commit op.
+ *
+ * Note: the bridge passed should be the one closest to the encoder
+ */
+void drm_bridge_pre_enable(struct drm_bridge *bridge)
+{
+	if (!bridge)
+		return;
+
+	drm_bridge_pre_enable(bridge->next);
+
+	if (bridge->funcs->pre_enable)
+		bridge->funcs->pre_enable(bridge);
+}
+EXPORT_SYMBOL(drm_bridge_pre_enable);
+
+/**
+ * drm_bridge_enable - enables all bridges in the encoder chain
+ * @bridge: bridge control structure
+ *
+ * Calls &drm_bridge_funcs.enable op for all the bridges in the encoder
+ * chain, starting from the first bridge to the last. These are called
+ * after completing the encoder's commit op.
+ *
+ * Note that the bridge passed should be the one closest to the encoder
+ */
+void drm_bridge_enable(struct drm_bridge *bridge)
+{
+	if (!bridge)
+		return;
+
+	if (bridge->funcs->enable)
+		bridge->funcs->enable(bridge);
+
+	drm_bridge_enable(bridge->next);
+}
+EXPORT_SYMBOL(drm_bridge_enable);
+
+#ifdef CONFIG_OF
+/**
+ * of_drm_find_bridge - find the bridge corresponding to the device node in
+ *			the global bridge list
+ *
+ * @np: device node
+ *
+ * RETURNS:
+ * drm_bridge control struct on success, NULL on failure
+ */
+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");