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
  22 struct 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
  30 static 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  */
  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         /* 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
  81 static void commit_destroy(struct msm_commit *c)
  82 {
  83         end_atomic(c->dev->dev_private, c->crtc_mask);
  84         kfree(c);
  85 }
  86
  87 static 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  */
 117 static 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
 156 static 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
 163 static 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
 169 int 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  */
 202 int 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
 293 error:
 294         drm_atomic_helper_cleanup_planes(dev, state);
 295         return ret;
 296 }