drivers/gpu/drm/vc4/vc4_kms.c

   1 /*
   2  * Copyright (C) 2015 Broadcom
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 /**
  10  * DOC: VC4 KMS
  11  *
  12  * This is the general code for implementing KMS mode setting that
  13  * doesn't clearly associate with any of the other objects (plane,
  14  * crtc, HDMI encoder).
  15  */
  16
  17 #include "drm_crtc.h"
  18 #include "drm_atomic.h"
  19 #include "drm_atomic_helper.h"
  20 #include "drm_crtc_helper.h"
  21 #include "drm_plane_helper.h"
  22 #include "drm_fb_cma_helper.h"
  23 #include "vc4_drv.h"
  24
  25 static void vc4_output_poll_changed(struct drm_device *dev)
  26 {
  27         struct vc4_dev *vc4 = to_vc4_dev(dev);
  28
  29         if (vc4->fbdev)
  30                 drm_fbdev_cma_hotplug_event(vc4->fbdev);
  31 }
  32
  33 struct vc4_commit {
  34         struct drm_device *dev;
  35         struct drm_atomic_state *state;
  36         struct vc4_seqno_cb cb;
  37 };
  38
  39 static void
  40 vc4_atomic_complete_commit(struct vc4_commit *c)
  41 {
  42         struct drm_atomic_state *state = c->state;
  43         struct drm_device *dev = state->dev;
  44         struct vc4_dev *vc4 = to_vc4_dev(dev);
  45
  46         drm_atomic_helper_commit_modeset_disables(dev, state);
  47
  48         drm_atomic_helper_commit_planes(dev, state, false);
  49
  50         drm_atomic_helper_commit_modeset_enables(dev, state);
  51
  52         /* Make sure that drm_atomic_helper_wait_for_vblanks()
  53          * actually waits for vblank.  If we're doing a full atomic
  54          * modeset (as opposed to a vc4_update_plane() short circuit),
  55          * then we need to wait for scanout to be done with our
  56          * display lists before we free it and potentially reallocate
  57          * and overwrite the dlist memory with a new modeset.
  58          */
  59         state->legacy_cursor_update = false;
  60
  61         drm_atomic_helper_wait_for_vblanks(dev, state);
  62
  63         drm_atomic_helper_cleanup_planes(dev, state);
  64
  65         drm_atomic_state_free(state);
  66
  67         up(&vc4->async_modeset);
  68
  69         kfree(c);
  70 }
  71
  72 static void
  73 vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb)
  74 {
  75         struct vc4_commit *c = container_of(cb, struct vc4_commit, cb);
  76
  77         vc4_atomic_complete_commit(c);
  78 }
  79
  80 static struct vc4_commit *commit_init(struct drm_atomic_state *state)
  81 {
  82         struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
  83
  84         if (!c)
  85                 return NULL;
  86         c->dev = state->dev;
  87         c->state = state;
  88
  89         return c;
  90 }
  91
  92 /**
  93  * vc4_atomic_commit - commit validated state object
  94  * @dev: DRM device
  95  * @state: the driver state object
  96  * @nonblock: nonblocking commit
  97  *
  98  * This function commits a with drm_atomic_helper_check() pre-validated state
  99  * object. This can still fail when e.g. the framebuffer reservation fails. For
 100  * now this doesn't implement asynchronous commits.
 101  *
 102  * RETURNS
 103  * Zero for success or -errno.
 104  */
 105 static int vc4_atomic_commit(struct drm_device *dev,
 106                              struct drm_atomic_state *state,
 107                              bool nonblock)
 108 {
 109         struct vc4_dev *vc4 = to_vc4_dev(dev);
 110         int ret;
 111         int i;
 112         uint64_t wait_seqno = 0;
 113         struct vc4_commit *c;
 114
 115         c = commit_init(state);
 116         if (!c)
 117                 return -ENOMEM;
 118
 119         /* Make sure that any outstanding modesets have finished. */
 120         ret = down_interruptible(&vc4->async_modeset);
 121         if (ret) {
 122                 kfree(c);
 123                 return ret;
 124         }
 125
 126         ret = drm_atomic_helper_prepare_planes(dev, state);
 127         if (ret) {
 128                 kfree(c);
 129                 up(&vc4->async_modeset);
 130                 return ret;
 131         }
 132
 133         for (i = 0; i < dev->mode_config.num_total_plane; i++) {
 134                 struct drm_plane *plane = state->planes[i];
 135                 struct drm_plane_state *new_state = state->plane_states[i];
 136
 137                 if (!plane)
 138                         continue;
 139
 140                 if ((plane->state->fb != new_state->fb) && new_state->fb) {
 141                         struct drm_gem_cma_object *cma_bo =
 142                                 drm_fb_cma_get_gem_obj(new_state->fb, 0);
 143                         struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
 144
 145                         wait_seqno = max(bo->seqno, wait_seqno);
 146                 }
 147         }
 148
 149         /*
 150          * This is the point of no return - everything below never fails except
 151          * when the hw goes bonghits. Which means we can commit the new state on
 152          * the software side now.
 153          */
 154
 155         drm_atomic_helper_swap_state(dev, state);
 156
 157         /*
 158          * Everything below can be run asynchronously without the need to grab
 159          * any modeset locks at all under one condition: It must be guaranteed
 160          * that the asynchronous work has either been cancelled (if the driver
 161          * supports it, which at least requires that the framebuffers get
 162          * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
 163          * before the new state gets committed on the software side with
 164          * drm_atomic_helper_swap_state().
 165          *
 166          * This scheme allows new atomic state updates to be prepared and
 167          * checked in parallel to the asynchronous completion of the previous
 168          * update. Which is important since compositors need to figure out the
 169          * composition of the next frame right after having submitted the
 170          * current layout.
 171          */
 172
 173         if (nonblock) {
 174                 vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
 175                                    vc4_atomic_complete_commit_seqno_cb);
 176         } else {
 177                 vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false);
 178                 vc4_atomic_complete_commit(c);
 179         }
 180
 181         return 0;
 182 }
 183
 184 static const struct drm_mode_config_funcs vc4_mode_funcs = {
 185         .output_poll_changed = vc4_output_poll_changed,
 186         .atomic_check = drm_atomic_helper_check,
 187         .atomic_commit = vc4_atomic_commit,
 188         .fb_create = drm_fb_cma_create,
 189 };
 190
 191 int vc4_kms_load(struct drm_device *dev)
 192 {
 193         struct vc4_dev *vc4 = to_vc4_dev(dev);
 194         int ret;
 195
 196         sema_init(&vc4->async_modeset, 1);
 197
 198         ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
 199         if (ret < 0) {
 200                 dev_err(dev->dev, "failed to initialize vblank\n");
 201                 return ret;
 202         }
 203
 204         dev->mode_config.max_width = 2048;
 205         dev->mode_config.max_height = 2048;
 206         dev->mode_config.funcs = &vc4_mode_funcs;
 207         dev->mode_config.preferred_depth = 24;
 208         dev->mode_config.async_page_flip = true;
 209
 210         drm_mode_config_reset(dev);
 211
 212         vc4->fbdev = drm_fbdev_cma_init(dev, 32,
 213                                         dev->mode_config.num_crtc,
 214                                         dev->mode_config.num_connector);
 215         if (IS_ERR(vc4->fbdev))
 216                 vc4->fbdev = NULL;
 217
 218         drm_kms_helper_poll_init(dev);
 219
 220         return 0;
 221 }