xref: /openbmc/linux/drivers/gpu/drm/vc4/vc4_kms.c (revision 48c926cd)
1 /*
2  * Copyright (C) 2015 Broadcom
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 /**
10  * DOC: VC4 KMS
11  *
12  * This is the general code for implementing KMS mode setting that
13  * doesn't clearly associate with any of the other objects (plane,
14  * crtc, HDMI encoder).
15  */
16 
17 #include <drm/drm_crtc.h>
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_crtc_helper.h>
21 #include <drm/drm_plane_helper.h>
22 #include <drm/drm_fb_cma_helper.h>
23 #include <drm/drm_gem_framebuffer_helper.h>
24 #include "vc4_drv.h"
25 
26 static void vc4_output_poll_changed(struct drm_device *dev)
27 {
28 	struct vc4_dev *vc4 = to_vc4_dev(dev);
29 
30 	drm_fbdev_cma_hotplug_event(vc4->fbdev);
31 }
32 
33 static void
34 vc4_atomic_complete_commit(struct drm_atomic_state *state)
35 {
36 	struct drm_device *dev = state->dev;
37 	struct vc4_dev *vc4 = to_vc4_dev(dev);
38 
39 	drm_atomic_helper_wait_for_fences(dev, state, false);
40 
41 	drm_atomic_helper_wait_for_dependencies(state);
42 
43 	drm_atomic_helper_commit_modeset_disables(dev, state);
44 
45 	drm_atomic_helper_commit_planes(dev, state, 0);
46 
47 	drm_atomic_helper_commit_modeset_enables(dev, state);
48 
49 	/* Make sure that drm_atomic_helper_wait_for_vblanks()
50 	 * actually waits for vblank.  If we're doing a full atomic
51 	 * modeset (as opposed to a vc4_update_plane() short circuit),
52 	 * then we need to wait for scanout to be done with our
53 	 * display lists before we free it and potentially reallocate
54 	 * and overwrite the dlist memory with a new modeset.
55 	 */
56 	state->legacy_cursor_update = false;
57 
58 	drm_atomic_helper_commit_hw_done(state);
59 
60 	drm_atomic_helper_wait_for_vblanks(dev, state);
61 
62 	drm_atomic_helper_cleanup_planes(dev, state);
63 
64 	drm_atomic_helper_commit_cleanup_done(state);
65 
66 	drm_atomic_state_put(state);
67 
68 	up(&vc4->async_modeset);
69 }
70 
71 static void commit_work(struct work_struct *work)
72 {
73 	struct drm_atomic_state *state = container_of(work,
74 						      struct drm_atomic_state,
75 						      commit_work);
76 	vc4_atomic_complete_commit(state);
77 }
78 
79 /**
80  * vc4_atomic_commit - commit validated state object
81  * @dev: DRM device
82  * @state: the driver state object
83  * @nonblock: nonblocking commit
84  *
85  * This function commits a with drm_atomic_helper_check() pre-validated state
86  * object. This can still fail when e.g. the framebuffer reservation fails. For
87  * now this doesn't implement asynchronous commits.
88  *
89  * RETURNS
90  * Zero for success or -errno.
91  */
92 static int vc4_atomic_commit(struct drm_device *dev,
93 			     struct drm_atomic_state *state,
94 			     bool nonblock)
95 {
96 	struct vc4_dev *vc4 = to_vc4_dev(dev);
97 	int ret;
98 
99 	ret = drm_atomic_helper_setup_commit(state, nonblock);
100 	if (ret)
101 		return ret;
102 
103 	INIT_WORK(&state->commit_work, commit_work);
104 
105 	ret = down_interruptible(&vc4->async_modeset);
106 	if (ret)
107 		return ret;
108 
109 	ret = drm_atomic_helper_prepare_planes(dev, state);
110 	if (ret) {
111 		up(&vc4->async_modeset);
112 		return ret;
113 	}
114 
115 	if (!nonblock) {
116 		ret = drm_atomic_helper_wait_for_fences(dev, state, true);
117 		if (ret) {
118 			drm_atomic_helper_cleanup_planes(dev, state);
119 			up(&vc4->async_modeset);
120 			return ret;
121 		}
122 	}
123 
124 	/*
125 	 * This is the point of no return - everything below never fails except
126 	 * when the hw goes bonghits. Which means we can commit the new state on
127 	 * the software side now.
128 	 */
129 
130 	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
131 
132 	/*
133 	 * Everything below can be run asynchronously without the need to grab
134 	 * any modeset locks at all under one condition: It must be guaranteed
135 	 * that the asynchronous work has either been cancelled (if the driver
136 	 * supports it, which at least requires that the framebuffers get
137 	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
138 	 * before the new state gets committed on the software side with
139 	 * drm_atomic_helper_swap_state().
140 	 *
141 	 * This scheme allows new atomic state updates to be prepared and
142 	 * checked in parallel to the asynchronous completion of the previous
143 	 * update. Which is important since compositors need to figure out the
144 	 * composition of the next frame right after having submitted the
145 	 * current layout.
146 	 */
147 
148 	drm_atomic_state_get(state);
149 	if (nonblock)
150 		queue_work(system_unbound_wq, &state->commit_work);
151 	else
152 		vc4_atomic_complete_commit(state);
153 
154 	return 0;
155 }
156 
157 static struct drm_framebuffer *vc4_fb_create(struct drm_device *dev,
158 					     struct drm_file *file_priv,
159 					     const struct drm_mode_fb_cmd2 *mode_cmd)
160 {
161 	struct drm_mode_fb_cmd2 mode_cmd_local;
162 
163 	/* If the user didn't specify a modifier, use the
164 	 * vc4_set_tiling_ioctl() state for the BO.
165 	 */
166 	if (!(mode_cmd->flags & DRM_MODE_FB_MODIFIERS)) {
167 		struct drm_gem_object *gem_obj;
168 		struct vc4_bo *bo;
169 
170 		gem_obj = drm_gem_object_lookup(file_priv,
171 						mode_cmd->handles[0]);
172 		if (!gem_obj) {
173 			DRM_DEBUG("Failed to look up GEM BO %d\n",
174 				  mode_cmd->handles[0]);
175 			return ERR_PTR(-ENOENT);
176 		}
177 		bo = to_vc4_bo(gem_obj);
178 
179 		mode_cmd_local = *mode_cmd;
180 
181 		if (bo->t_format) {
182 			mode_cmd_local.modifier[0] =
183 				DRM_FORMAT_MOD_BROADCOM_VC4_T_TILED;
184 		} else {
185 			mode_cmd_local.modifier[0] = DRM_FORMAT_MOD_NONE;
186 		}
187 
188 		drm_gem_object_put_unlocked(gem_obj);
189 
190 		mode_cmd = &mode_cmd_local;
191 	}
192 
193 	return drm_gem_fb_create(dev, file_priv, mode_cmd);
194 }
195 
196 static const struct drm_mode_config_funcs vc4_mode_funcs = {
197 	.output_poll_changed = vc4_output_poll_changed,
198 	.atomic_check = drm_atomic_helper_check,
199 	.atomic_commit = vc4_atomic_commit,
200 	.fb_create = vc4_fb_create,
201 };
202 
203 int vc4_kms_load(struct drm_device *dev)
204 {
205 	struct vc4_dev *vc4 = to_vc4_dev(dev);
206 	int ret;
207 
208 	sema_init(&vc4->async_modeset, 1);
209 
210 	/* Set support for vblank irq fast disable, before drm_vblank_init() */
211 	dev->vblank_disable_immediate = true;
212 
213 	ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
214 	if (ret < 0) {
215 		dev_err(dev->dev, "failed to initialize vblank\n");
216 		return ret;
217 	}
218 
219 	dev->mode_config.max_width = 2048;
220 	dev->mode_config.max_height = 2048;
221 	dev->mode_config.funcs = &vc4_mode_funcs;
222 	dev->mode_config.preferred_depth = 24;
223 	dev->mode_config.async_page_flip = true;
224 
225 	drm_mode_config_reset(dev);
226 
227 	if (dev->mode_config.num_connector) {
228 		vc4->fbdev = drm_fbdev_cma_init(dev, 32,
229 						dev->mode_config.num_connector);
230 		if (IS_ERR(vc4->fbdev))
231 			vc4->fbdev = NULL;
232 	}
233 
234 	drm_kms_helper_poll_init(dev);
235 
236 	return 0;
237 }
238