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