drivers/gpu/drm/msm/msm_atomic.c

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