1/*
  2 * Copyright (C) 2014 Red Hat
  3 * Author: Rob Clark <robdclark@gmail.com>
  4 *
  5 * This program is free software; you can redistribute it and/or modify it
  6 * under the terms of the GNU General Public License version 2 as published by
  7 * the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it will be useful, but WITHOUT
 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 12 * more details.
 13 *
 14 * You should have received a copy of the GNU General Public License along with
 15 * this program.  If not, see <http://www.gnu.org/licenses/>.
 16 */
 17
 18#include "msm_drv.h"
 19#include "msm_kms.h"
 20#include "msm_gem.h"
 21#include "msm_fence.h"
 22
 23struct msm_commit {
 24	struct drm_device *dev;
 25	struct drm_atomic_state *state;
 26	struct work_struct work;
 27	uint32_t crtc_mask;
 28};
 29
 30static void commit_worker(struct work_struct *work);
 31
 32/* block until specified crtcs are no longer pending update, and
 33 * atomically mark them as pending update
 34 */
 35static int start_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
 36{
 37	int ret;
 38
 39	spin_lock(&priv->pending_crtcs_event.lock);
 40	ret = wait_event_interruptible_locked(priv->pending_crtcs_event,
 41			!(priv->pending_crtcs & crtc_mask));
 42	if (ret == 0) {
 43		DBG("start: %08x", crtc_mask);
 44		priv->pending_crtcs |= crtc_mask;
 45	}
 46	spin_unlock(&priv->pending_crtcs_event.lock);
 47
 48	return ret;
 49}
 50
 51/* clear specified crtcs (no longer pending update)
 52 */
 53static void end_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
 54{
 55	spin_lock(&priv->pending_crtcs_event.lock);
 56	DBG("end: %08x", crtc_mask);
 57	priv->pending_crtcs &= ~crtc_mask;
 58	wake_up_all_locked(&priv->pending_crtcs_event);
 59	spin_unlock(&priv->pending_crtcs_event.lock);
 60}
 61
 62static struct msm_commit *commit_init(struct drm_atomic_state *state)
 63{
 64	struct msm_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
 65
 66	if (!c)
 67		return NULL;
 68
 69	c->dev = state->dev;
 70	c->state = state;
 71
 72	INIT_WORK(&c->work, commit_worker);
 73
 74	return c;
 75}
 76
 77static void commit_destroy(struct msm_commit *c)
 78{
 79	end_atomic(c->dev->dev_private, c->crtc_mask);
 80	kfree(c);
 81}
 82
 83static void msm_atomic_wait_for_commit_done(struct drm_device *dev,
 84		struct drm_atomic_state *old_state)
 85{
 86	struct drm_crtc *crtc;
 87	struct drm_crtc_state *crtc_state;
 88	struct msm_drm_private *priv = old_state->dev->dev_private;
 89	struct msm_kms *kms = priv->kms;
 90	int i;
 91
 92	for_each_crtc_in_state(old_state, crtc, crtc_state, i) {
 93		if (!crtc->state->enable)
 94			continue;
 95
 96		/* Legacy cursor ioctls are completely unsynced, and userspace
 97		 * relies on that (by doing tons of cursor updates). */
 98		if (old_state->legacy_cursor_update)
 99			continue;
100
101		kms->funcs->wait_for_crtc_commit_done(kms, crtc);
102	}
103}
104
105/* The (potentially) asynchronous part of the commit.  At this point
106 * nothing can fail short of armageddon.
107 */
108static void complete_commit(struct msm_commit *c, bool async)
109{
110	struct drm_atomic_state *state = c->state;
111	struct drm_device *dev = state->dev;
112	struct msm_drm_private *priv = dev->dev_private;
113	struct msm_kms *kms = priv->kms;
114
115	drm_atomic_helper_wait_for_fences(dev, state, false);
116
117	kms->funcs->prepare_commit(kms, state);
118
119	drm_atomic_helper_commit_modeset_disables(dev, state);
120
121	drm_atomic_helper_commit_planes(dev, state, 0);
122
123	drm_atomic_helper_commit_modeset_enables(dev, state);
124
125	/* NOTE: _wait_for_vblanks() only waits for vblank on
126	 * enabled CRTCs.  So we end up faulting when disabling
127	 * due to (potentially) unref'ing the outgoing fb's
128	 * before the vblank when the disable has latched.
129	 *
130	 * But if it did wait on disabled (or newly disabled)
131	 * CRTCs, that would be racy (ie. we could have missed
132	 * the irq.  We need some way to poll for pipe shut
133	 * down.  Or just live with occasionally hitting the
134	 * timeout in the CRTC disable path (which really should
135	 * not be critical path)
136	 */
137
138	msm_atomic_wait_for_commit_done(dev, state);
139
140	drm_atomic_helper_cleanup_planes(dev, state);
141
142	kms->funcs->complete_commit(kms, state);
143
144	drm_atomic_state_put(state);
145
146	commit_destroy(c);
147}
148
149static void commit_worker(struct work_struct *work)
150{
151	complete_commit(container_of(work, struct msm_commit, work), true);
152}
153
154int msm_atomic_check(struct drm_device *dev,
155		     struct drm_atomic_state *state)
156{
157	int ret;
158
159	/*
160	 * msm ->atomic_check can update ->mode_changed for pixel format
161	 * changes, hence must be run before we check the modeset changes.
162	 */
163	ret = drm_atomic_helper_check_planes(dev, state);
164	if (ret)
165		return ret;
166
167	ret = drm_atomic_helper_check_modeset(dev, state);
168	if (ret)
169		return ret;
170
171	return ret;
172}
173
174/**
175 * drm_atomic_helper_commit - commit validated state object
176 * @dev: DRM device
177 * @state: the driver state object
178 * @nonblock: nonblocking commit
179 *
180 * This function commits a with drm_atomic_helper_check() pre-validated state
181 * object. This can still fail when e.g. the framebuffer reservation fails.
182 *
183 * RETURNS
184 * Zero for success or -errno.
185 */
186int msm_atomic_commit(struct drm_device *dev,
187		struct drm_atomic_state *state, bool nonblock)
188{
189	struct msm_drm_private *priv = dev->dev_private;
190	struct msm_commit *c;
191	struct drm_crtc *crtc;
192	struct drm_crtc_state *crtc_state;
193	struct drm_plane *plane;
194	struct drm_plane_state *plane_state;
195	int i, ret;
196
197	ret = drm_atomic_helper_prepare_planes(dev, state);
198	if (ret)
199		return ret;
200
201	c = commit_init(state);
202	if (!c) {
203		ret = -ENOMEM;
204		goto error;
205	}
206
207	/*
208	 * Figure out what crtcs we have:
209	 */
210	for_each_crtc_in_state(state, crtc, crtc_state, i)
211		c->crtc_mask |= drm_crtc_mask(crtc);
212
213	/*
214	 * Figure out what fence to wait for:
215	 */
216	for_each_plane_in_state(state, plane, plane_state, i) {
217		if ((plane->state->fb != plane_state->fb) && plane_state->fb) {
218			struct drm_gem_object *obj = msm_framebuffer_bo(plane_state->fb, 0);
219			struct msm_gem_object *msm_obj = to_msm_bo(obj);
220			struct dma_fence *fence = reservation_object_get_excl_rcu(msm_obj->resv);
221
222			drm_atomic_set_fence_for_plane(plane_state, fence);
223		}
224	}
225
226	/*
227	 * Wait for pending updates on any of the same crtc's and then
228	 * mark our set of crtc's as busy:
229	 */
230	ret = start_atomic(dev->dev_private, c->crtc_mask);
231	if (ret) {
232		kfree(c);
233		goto error;
234	}
235
236	/*
237	 * This is the point of no return - everything below never fails except
238	 * when the hw goes bonghits. Which means we can commit the new state on
239	 * the software side now.
240	 */
241
242	drm_atomic_helper_swap_state(state, true);
243
244	/* swap driver private state while still holding state_lock */
245	if (to_kms_state(state)->state)
246		priv->kms->funcs->swap_state(priv->kms, state);
247
248	/*
249	 * Everything below can be run asynchronously without the need to grab
250	 * any modeset locks at all under one conditions: It must be guaranteed
251	 * that the asynchronous work has either been cancelled (if the driver
252	 * supports it, which at least requires that the framebuffers get
253	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
254	 * before the new state gets committed on the software side with
255	 * drm_atomic_helper_swap_state().
256	 *
257	 * This scheme allows new atomic state updates to be prepared and
258	 * checked in parallel to the asynchronous completion of the previous
259	 * update. Which is important since compositors need to figure out the
260	 * composition of the next frame right after having submitted the
261	 * current layout.
262	 */
263
264	drm_atomic_state_get(state);
265	if (nonblock) {
266		queue_work(priv->atomic_wq, &c->work);
267		return 0;
268	}
269
270	complete_commit(c, false);
271
272	return 0;
273
274error:
275	drm_atomic_helper_cleanup_planes(dev, state);
276	return ret;
277}
278
279struct drm_atomic_state *msm_atomic_state_alloc(struct drm_device *dev)
280{
281	struct msm_kms_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
282
283	if (!state || drm_atomic_state_init(dev, &state->base) < 0) {
284		kfree(state);
285		return NULL;
286	}
287
288	return &state->base;
289}
290
291void msm_atomic_state_clear(struct drm_atomic_state *s)
292{
293	struct msm_kms_state *state = to_kms_state(s);
294	drm_atomic_state_default_clear(&state->base);
295	kfree(state->state);
296	state->state = NULL;
297}
298
299void msm_atomic_state_free(struct drm_atomic_state *state)
300{
301	kfree(to_kms_state(state)->state);
302	drm_atomic_state_default_release(state);
303	kfree(state);
304}