1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
  4 */
  5
  6#include <drm/drm_atomic_helper.h>
  7#include <drm/drm_atomic.h>
  8#include <drm/drm_bridge.h>
  9#include <drm/drm_bridge_connector.h>
 10#include <drm/drm_crtc.h>
 11
 12#include "msm_drv.h"
 13#include "msm_kms.h"
 14#include "dp_drm.h"
 15
 16/**
 17 * dp_bridge_detect - callback to determine if connector is connected
 18 * @bridge: Pointer to drm bridge structure
 19 * Returns: Bridge's 'is connected' status
 20 */
 21static enum drm_connector_status dp_bridge_detect(struct drm_bridge *bridge)
 22{
 23	struct msm_dp *dp;
 24
 25	dp = to_dp_bridge(bridge)->dp_display;
 26
 27	drm_dbg_dp(dp->drm_dev, "is_connected = %s\n",
 28		(dp->is_connected) ? "true" : "false");
 29
 30	return (dp->is_connected) ? connector_status_connected :
 31					connector_status_disconnected;
 32}
 33
 34static int dp_bridge_atomic_check(struct drm_bridge *bridge,
 35			    struct drm_bridge_state *bridge_state,
 36			    struct drm_crtc_state *crtc_state,
 37			    struct drm_connector_state *conn_state)
 38{
 39	struct msm_dp *dp;
 40
 41	dp = to_dp_bridge(bridge)->dp_display;
 42
 43	drm_dbg_dp(dp->drm_dev, "is_connected = %s\n",
 44		(dp->is_connected) ? "true" : "false");
 45
 46	/*
 47	 * There is no protection in the DRM framework to check if the display
 48	 * pipeline has been already disabled before trying to disable it again.
 49	 * Hence if the sink is unplugged, the pipeline gets disabled, but the
 50	 * crtc->active is still true. Any attempt to set the mode or manually
 51	 * disable this encoder will result in the crash.
 52	 *
 53	 * TODO: add support for telling the DRM subsystem that the pipeline is
 54	 * disabled by the hardware and thus all access to it should be forbidden.
 55	 * After that this piece of code can be removed.
 56	 */
 57	if (bridge->ops & DRM_BRIDGE_OP_HPD)
 58		return (dp->is_connected) ? 0 : -ENOTCONN;
 59
 60	return 0;
 61}
 62
 63
 64/**
 65 * dp_bridge_get_modes - callback to add drm modes via drm_mode_probed_add()
 66 * @bridge: Poiner to drm bridge
 67 * @connector: Pointer to drm connector structure
 68 * Returns: Number of modes added
 69 */
 70static int dp_bridge_get_modes(struct drm_bridge *bridge, struct drm_connector *connector)
 71{
 72	int rc = 0;
 73	struct msm_dp *dp;
 74
 75	if (!connector)
 76		return 0;
 77
 78	dp = to_dp_bridge(bridge)->dp_display;
 79
 80	/* pluggable case assumes EDID is read when HPD */
 81	if (dp->is_connected) {
 82		rc = dp_display_get_modes(dp);
 83		if (rc <= 0) {
 84			DRM_ERROR("failed to get DP sink modes, rc=%d\n", rc);
 85			return rc;
 86		}
 87	} else {
 88		drm_dbg_dp(connector->dev, "No sink connected\n");
 89	}
 90	return rc;
 91}
 92
 93static const struct drm_bridge_funcs dp_bridge_ops = {
 94	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 95	.atomic_destroy_state   = drm_atomic_helper_bridge_destroy_state,
 96	.atomic_reset           = drm_atomic_helper_bridge_reset,
 97	.enable       = dp_bridge_enable,
 98	.disable      = dp_bridge_disable,
 99	.post_disable = dp_bridge_post_disable,
100	.mode_set     = dp_bridge_mode_set,
101	.mode_valid   = dp_bridge_mode_valid,
102	.get_modes    = dp_bridge_get_modes,
103	.detect       = dp_bridge_detect,
104	.atomic_check = dp_bridge_atomic_check,
105};
106
107struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
108			struct drm_encoder *encoder)
109{
110	int rc;
111	struct msm_dp_bridge *dp_bridge;
112	struct drm_bridge *bridge;
113
114	dp_bridge = devm_kzalloc(dev->dev, sizeof(*dp_bridge), GFP_KERNEL);
115	if (!dp_bridge)
116		return ERR_PTR(-ENOMEM);
117
118	dp_bridge->dp_display = dp_display;
119
120	bridge = &dp_bridge->bridge;
121	bridge->funcs = &dp_bridge_ops;
122	bridge->type = dp_display->connector_type;
123
124	/*
125	 * Many ops only make sense for DP. Why?
126	 * - Detect/HPD are used by DRM to know if a display is _physically_
127	 *   there, not whether the display is powered on / finished initting.
128	 *   On eDP we assume the display is always there because you can't
129	 *   know until power is applied. If we don't implement the ops DRM will
130	 *   assume our display is always there.
131	 * - Currently eDP mode reading is driven by the panel driver. This
132	 *   allows the panel driver to properly power itself on to read the
133	 *   modes.
134	 */
135	if (!dp_display->is_edp) {
136		bridge->ops =
137			DRM_BRIDGE_OP_DETECT |
138			DRM_BRIDGE_OP_HPD |
139			DRM_BRIDGE_OP_MODES;
140	}
141
142	drm_bridge_add(bridge);
143
144	rc = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
145	if (rc) {
146		DRM_ERROR("failed to attach bridge, rc=%d\n", rc);
147		drm_bridge_remove(bridge);
148
149		return ERR_PTR(rc);
150	}
151
152	if (dp_display->next_bridge) {
153		rc = drm_bridge_attach(encoder,
154					dp_display->next_bridge, bridge,
155					DRM_BRIDGE_ATTACH_NO_CONNECTOR);
156		if (rc < 0) {
157			DRM_ERROR("failed to attach panel bridge: %d\n", rc);
158			drm_bridge_remove(bridge);
159			return ERR_PTR(rc);
160		}
161	}
162
163	return bridge;
164}
165
166/* connector initialization */
167struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display, struct drm_encoder *encoder)
168{
169	struct drm_connector *connector = NULL;
170
171	connector = drm_bridge_connector_init(dp_display->drm_dev, encoder);
172	if (IS_ERR(connector))
173		return connector;
174
175	drm_connector_attach_encoder(connector, encoder);
176
177	return connector;
178}