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         drm_fbdev_cma_hotplug_event(vc4->fbdev);
  30 }
  31
  32 struct vc4_commit {
  33         struct drm_device *dev;
  34         struct drm_atomic_state *state;
  35         struct vc4_seqno_cb cb;
  36 };
  37
  38 static void
  39 vc4_atomic_complete_commit(struct vc4_commit *c)
  40 {
  41         struct drm_atomic_state *state = c->state;
  42         struct drm_device *dev = state->dev;
  43         struct vc4_dev *vc4 = to_vc4_dev(dev);
  44
  45         drm_atomic_helper_commit_modeset_disables(dev, state);
  46
  47         drm_atomic_helper_commit_planes(dev, state, false);
  48
  49         drm_atomic_helper_commit_modeset_enables(dev, state);
  50
  51         /* Make sure that drm_atomic_helper_wait_for_vblanks()
  52          * actually waits for vblank.  If we're doing a full atomic
  53          * modeset (as opposed to a vc4_update_plane() short circuit),
  54          * then we need to wait for scanout to be done with our
  55          * display lists before we free it and potentially reallocate
  56          * and overwrite the dlist memory with a new modeset.
  57          */
  58         state->legacy_cursor_update = false;
  59
  60         drm_atomic_helper_wait_for_vblanks(dev, state);
  61
  62         drm_atomic_helper_cleanup_planes(dev, state);
  63
  64         drm_atomic_state_free(state);
  65
  66         up(&vc4->async_modeset);
  67
  68         kfree(c);
  69 }
  70
  71 static void
  72 vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb)
  73 {
  74         struct vc4_commit *c = container_of(cb, struct vc4_commit, cb);
  75
  76         vc4_atomic_complete_commit(c);
  77 }
  78
  79 static struct vc4_commit *commit_init(struct drm_atomic_state *state)
  80 {
  81         struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
  82
  83         if (!c)
  84                 return NULL;
  85         c->dev = state->dev;
  86         c->state = state;
  87
  88         return c;
  89 }
  90
  91 /**
  92  * vc4_atomic_commit - commit validated state object
  93  * @dev: DRM device
  94  * @state: the driver state object
  95  * @nonblock: nonblocking commit
  96  *
  97  * This function commits a with drm_atomic_helper_check() pre-validated state
  98  * object. This can still fail when e.g. the framebuffer reservation fails. For
  99  * now this doesn't implement asynchronous commits.
 100  *
 101  * RETURNS
 102  * Zero for success or -errno.
 103  */
 104 static int vc4_atomic_commit(struct drm_device *dev,
 105                              struct drm_atomic_state *state,
 106                              bool nonblock)
 107 {
 108         struct vc4_dev *vc4 = to_vc4_dev(dev);
 109         int ret;
 110         int i;
 111         uint64_t wait_seqno = 0;
 112         struct vc4_commit *c;
 113         struct drm_plane *plane;
 114         struct drm_plane_state *new_state;
 115
 116         c = commit_init(state);
 117         if (!c)
 118                 return -ENOMEM;
 119
 120         /* Make sure that any outstanding modesets have finished. */
 121         if (nonblock) {
 122                 ret = down_trylock(&vc4->async_modeset);
 123                 if (ret) {
 124                         kfree(c);
 125                         return -EBUSY;
 126                 }
 127         } else {
 128                 ret = down_interruptible(&vc4->async_modeset);
 129                 if (ret) {
 130                         kfree(c);
 131                         return ret;
 132                 }
 133         }
 134
 135         ret = drm_atomic_helper_prepare_planes(dev, state);
 136         if (ret) {
 137                 kfree(c);
 138                 up(&vc4->async_modeset);
 139                 return ret;
 140         }
 141
 142         for_each_plane_in_state(state, plane, new_state, i) {
 143                 if ((plane->state->fb != new_state->fb) && new_state->fb) {
 144                         struct drm_gem_cma_object *cma_bo =
 145                                 drm_fb_cma_get_gem_obj(new_state->fb, 0);
 146                         struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
 147
 148                         wait_seqno = max(bo->seqno, wait_seqno);
 149                 }
 150         }
 151
 152         /*
 153          * This is the point of no return - everything below never fails except
 154          * when the hw goes bonghits. Which means we can commit the new state on
 155          * the software side now.
 156          */
 157
 158         drm_atomic_helper_swap_state(state, true);
 159
 160         /*
 161          * Everything below can be run asynchronously without the need to grab
 162          * any modeset locks at all under one condition: It must be guaranteed
 163          * that the asynchronous work has either been cancelled (if the driver
 164          * supports it, which at least requires that the framebuffers get
 165          * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
 166          * before the new state gets committed on the software side with
 167          * drm_atomic_helper_swap_state().
 168          *
 169          * This scheme allows new atomic state updates to be prepared and
 170          * checked in parallel to the asynchronous completion of the previous
 171          * update. Which is important since compositors need to figure out the
 172          * composition of the next frame right after having submitted the
 173          * current layout.
 174          */
 175
 176         if (nonblock) {
 177                 vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
 178                                    vc4_atomic_complete_commit_seqno_cb);
 179         } else {
 180                 vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false);
 181                 vc4_atomic_complete_commit(c);
 182         }
 183
 184         return 0;
 185 }
 186
 187 static const struct drm_mode_config_funcs vc4_mode_funcs = {
 188         .output_poll_changed = vc4_output_poll_changed,
 189         .atomic_check = drm_atomic_helper_check,
 190         .atomic_commit = vc4_atomic_commit,
 191         .fb_create = drm_fb_cma_create,
 192 };
 193
 194 int vc4_kms_load(struct drm_device *dev)
 195 {
 196         struct vc4_dev *vc4 = to_vc4_dev(dev);
 197         int ret;
 198
 199         sema_init(&vc4->async_modeset, 1);
 200
 201         ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
 202         if (ret < 0) {
 203                 dev_err(dev->dev, "failed to initialize vblank\n");
 204                 return ret;
 205         }
 206
 207         dev->mode_config.max_width = 2048;
 208         dev->mode_config.max_height = 2048;
 209         dev->mode_config.funcs = &vc4_mode_funcs;
 210         dev->mode_config.preferred_depth = 24;
 211         dev->mode_config.async_page_flip = true;
 212
 213         drm_mode_config_reset(dev);
 214
 215         vc4->fbdev = drm_fbdev_cma_init(dev, 32,
 216                                         dev->mode_config.num_crtc,
 217                                         dev->mode_config.num_connector);
 218         if (IS_ERR(vc4->fbdev))
 219                 vc4->fbdev = NULL;
 220
 221         drm_kms_helper_poll_init(dev);
 222
 223         return 0;
 224 }