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
 22struct msm_commit {
 23	struct drm_device *dev;
 24	struct drm_atomic_state *state;
 25	uint32_t fence;
 26	struct msm_fence_cb fence_cb;
 27	uint32_t crtc_mask;
 28};
 29
 30static void fence_cb(struct msm_fence_cb *cb);
 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	/* TODO we might need a way to indicate to run the cb on a
 73	 * different wq so wait_for_vblanks() doesn't block retiring
 74	 * bo's..
 75	 */
 76	INIT_FENCE_CB(&c->fence_cb, fence_cb);
 77
 78	return c;
 79}
 80
 81static void commit_destroy(struct msm_commit *c)
 82{
 83	end_atomic(c->dev->dev_private, c->crtc_mask);
 84	kfree(c);
 85}
 86
 87static void msm_atomic_wait_for_commit_done(struct drm_device *dev,
 88		struct drm_atomic_state *old_state)
 89{
 90	struct drm_crtc *crtc;
 91	struct msm_drm_private *priv = old_state->dev->dev_private;
 92	struct msm_kms *kms = priv->kms;
 93	int ncrtcs = old_state->dev->mode_config.num_crtc;
 94	int i;
 95
 96	for (i = 0; i < ncrtcs; i++) {
 97		crtc = old_state->crtcs[i];
 98
 99		if (!crtc)
100			continue;
101
102		if (!crtc->state->enable)
103			continue;
104
105		/* Legacy cursor ioctls are completely unsynced, and userspace
106		 * relies on that (by doing tons of cursor updates). */
107		if (old_state->legacy_cursor_update)
108			continue;
109
110		kms->funcs->wait_for_crtc_commit_done(kms, crtc);
111	}
112}
113
114/* The (potentially) asynchronous part of the commit.  At this point
115 * nothing can fail short of armageddon.
116 */
117static void complete_commit(struct msm_commit *c)
118{
119	struct drm_atomic_state *state = c->state;
120	struct drm_device *dev = state->dev;
121	struct msm_drm_private *priv = dev->dev_private;
122	struct msm_kms *kms = priv->kms;
123
124	kms->funcs->prepare_commit(kms, state);
125
126	drm_atomic_helper_commit_modeset_disables(dev, state);
127
128	drm_atomic_helper_commit_planes(dev, state, false);
129
130	drm_atomic_helper_commit_modeset_enables(dev, state);
131
132	/* NOTE: _wait_for_vblanks() only waits for vblank on
133	 * enabled CRTCs.  So we end up faulting when disabling
134	 * due to (potentially) unref'ing the outgoing fb's
135	 * before the vblank when the disable has latched.
136	 *
137	 * But if it did wait on disabled (or newly disabled)
138	 * CRTCs, that would be racy (ie. we could have missed
139	 * the irq.  We need some way to poll for pipe shut
140	 * down.  Or just live with occasionally hitting the
141	 * timeout in the CRTC disable path (which really should
142	 * not be critical path)
143	 */
144
145	msm_atomic_wait_for_commit_done(dev, state);
146
147	drm_atomic_helper_cleanup_planes(dev, state);
148
149	kms->funcs->complete_commit(kms, state);
150
151	drm_atomic_state_free(state);
152
153	commit_destroy(c);
154}
155
156static void fence_cb(struct msm_fence_cb *cb)
157{
158	struct msm_commit *c =
159			container_of(cb, struct msm_commit, fence_cb);
160	complete_commit(c);
161}
162
163static void add_fb(struct msm_commit *c, struct drm_framebuffer *fb)
164{
165	struct drm_gem_object *obj = msm_framebuffer_bo(fb, 0);
166	c->fence = max(c->fence, msm_gem_fence(to_msm_bo(obj), MSM_PREP_READ));
167}
168
169int msm_atomic_check(struct drm_device *dev,
170		     struct drm_atomic_state *state)
171{
172	int ret;
173
174	/*
175	 * msm ->atomic_check can update ->mode_changed for pixel format
176	 * changes, hence must be run before we check the modeset changes.
177	 */
178	ret = drm_atomic_helper_check_planes(dev, state);
179	if (ret)
180		return ret;
181
182	ret = drm_atomic_helper_check_modeset(dev, state);
183	if (ret)
184		return ret;
185
186	return ret;
187}
188
189/**
190 * drm_atomic_helper_commit - commit validated state object
191 * @dev: DRM device
192 * @state: the driver state object
193 * @async: asynchronous commit
194 *
195 * This function commits a with drm_atomic_helper_check() pre-validated state
196 * object. This can still fail when e.g. the framebuffer reservation fails. For
197 * now this doesn't implement asynchronous commits.
198 *
199 * RETURNS
200 * Zero for success or -errno.
201 */
202int msm_atomic_commit(struct drm_device *dev,
203		struct drm_atomic_state *state, bool async)
204{
205	int nplanes = dev->mode_config.num_total_plane;
206	int ncrtcs = dev->mode_config.num_crtc;
207	ktime_t timeout;
208	struct msm_commit *c;
209	int i, ret;
210
211	ret = drm_atomic_helper_prepare_planes(dev, state);
212	if (ret)
213		return ret;
214
215	c = commit_init(state);
216	if (!c) {
217		ret = -ENOMEM;
218		goto error;
219	}
220
221	/*
222	 * Figure out what crtcs we have:
223	 */
224	for (i = 0; i < ncrtcs; i++) {
225		struct drm_crtc *crtc = state->crtcs[i];
226		if (!crtc)
227			continue;
228		c->crtc_mask |= (1 << drm_crtc_index(crtc));
229	}
230
231	/*
232	 * Figure out what fence to wait for:
233	 */
234	for (i = 0; i < nplanes; i++) {
235		struct drm_plane *plane = state->planes[i];
236		struct drm_plane_state *new_state = state->plane_states[i];
237
238		if (!plane)
239			continue;
240
241		if ((plane->state->fb != new_state->fb) && new_state->fb)
242			add_fb(c, new_state->fb);
243	}
244
245	/*
246	 * Wait for pending updates on any of the same crtc's and then
247	 * mark our set of crtc's as busy:
248	 */
249	ret = start_atomic(dev->dev_private, c->crtc_mask);
250	if (ret) {
251		kfree(c);
252		goto error;
253	}
254
255	/*
256	 * This is the point of no return - everything below never fails except
257	 * when the hw goes bonghits. Which means we can commit the new state on
258	 * the software side now.
259	 */
260
261	drm_atomic_helper_swap_state(dev, state);
262
263	/*
264	 * Everything below can be run asynchronously without the need to grab
265	 * any modeset locks at all under one conditions: It must be guaranteed
266	 * that the asynchronous work has either been cancelled (if the driver
267	 * supports it, which at least requires that the framebuffers get
268	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
269	 * before the new state gets committed on the software side with
270	 * drm_atomic_helper_swap_state().
271	 *
272	 * This scheme allows new atomic state updates to be prepared and
273	 * checked in parallel to the asynchronous completion of the previous
274	 * update. Which is important since compositors need to figure out the
275	 * composition of the next frame right after having submitted the
276	 * current layout.
277	 */
278
279	if (async) {
280		msm_queue_fence_cb(dev, &c->fence_cb, c->fence);
281		return 0;
282	}
283
284	timeout = ktime_add_ms(ktime_get(), 1000);
285
286	/* uninterruptible wait */
287	msm_wait_fence(dev, c->fence, &timeout, false);
288
289	complete_commit(c);
290
291	return 0;
292
293error:
294	drm_atomic_helper_cleanup_planes(dev, state);
295	return ret;
296}