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