drm/fence: add out-fences support

Support DRM out-fences by creating a sync_file with a fence for each CRTC
that sets the OUT_FENCE_PTR property.

We use the out_fence pointer received in the OUT_FENCE_PTR prop to send
the sync_file fd back to userspace.

The sync_file and fd are allocated/created before commit, but the
fd_install operation only happens after we know that commit succeed.

v2: Comment by Rob Clark:
	- Squash commit that adds DRM_MODE_ATOMIC_OUT_FENCE flag here.

    Comment by Daniel Vetter:
	- Add clean up code for out_fences

v3: Comments by Daniel Vetter:
	- create DRM_MODE_ATOMIC_EVENT_MASK
	- userspace should fill out_fences_ptr with the crtc_ids for which
	it wants fences back.

v4: Create OUT_FENCE_PTR properties and remove old approach.

v5: Comments by Brian Starkey:
	- Remove extra fence_get() in atomic_ioctl()
	- Check ret before iterating on the crtc_state
	- check ret before fd_install
	- set fence_state to NULL at the beginning
	- check fence_state->out_fence_ptr before put_user()
	- change order of fput() and put_unused_fd() on failure

     - Add access_ok() check to the out_fence_ptr received
     - Rebase after fence -> dma_fence rename
     - Store out_fence_ptr in the drm_atomic_state
     - Split crtc_setup_out_fence()
     - return -1 as out_fence with TEST_ONLY flag

v6: Comments by Daniel Vetter
	- Add prepare/unprepare_crtc_signaling()
	- move struct drm_out_fence_state to drm_atomic.c
	- mark get_crtc_fence() as static

    Comments by Brian Starkey
	- proper set fence_ptr fence_state array
	- isolate fence_idx increment

    - improve error handling

v7: Comments by Daniel Vetter
	- remove prefix from internal functions
	- make out_fence_ptr an s64 pointer
	- degrade DRM_INFO to DRM_DEBUG_ATOMIC when put_user fail
	- fix doc issues
	- filter out OUT_FENCE_PTR == NULL and do not fail in this case
	- add complete_crtc_signalling()
	- krealloc fence_state on demand

    Comment by Brian Starkey
	- remove unused crtc_state arg from get_out_fence()

v8: Comment by Brian Starkey
	- cancel events before check for !fence_state
	- convert a few lefovers u64 types for out_fence_ptr
	- fix memleak by assign fence_state earlier after realloc
	- proper accout num_fences in case of error

v9: Comment by Brian Starkey
	- memset last position of fence_state after krealloc
    Comments by Sean Paul
	- pass install_fds in complete_crtc_signaling() instead of ret

     - put_user(-1, fence_ptr) when decoding props

v10: Comment by Brian Starkey
	- remove unneeded num_fences increment on error path
	- kfree fence_state after installing fences fd

v11: rebase against latest drm-misc

v12: rebase again against latest drm-misc

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Brian Starkey <brian.starkey@arm.com> (v10)
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Tested-by: Robert Foss <robert.foss@collabora.com> (v10)
[danvet: Appease checkpatch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1479301221-13056-1-git-send-email-gustavo@padovan.org

5 files changed, 211 insertions, 45 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 3ad780ad24f9..b476ec585547 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -290,6 +290,23 @@ drm_atomic_get_crtc_state(struct drm_atomic_state *state,
 }
 EXPORT_SYMBOL(drm_atomic_get_crtc_state);
 
+static void set_out_fence_for_crtc(struct drm_atomic_state *state,
+                                   struct drm_crtc *crtc, s64 __user *fence_ptr)
+{
+        state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = fence_ptr;
+}
+
+static s64 __user *get_out_fence_for_crtc(struct drm_atomic_state *state,
+                                          struct drm_crtc *crtc)
+{
+        s64 __user *fence_ptr;
+
+        fence_ptr = state->crtcs[drm_crtc_index(crtc)].out_fence_ptr;
+        state->crtcs[drm_crtc_index(crtc)].out_fence_ptr = NULL;
+
+        return fence_ptr;
+}
+
 /**
  * drm_atomic_set_mode_for_crtc - set mode for CRTC
  * @state: the CRTC whose incoming state to update
@@ -494,6 +511,16 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
                                         &replaced);
                 state->color_mgmt_changed |= replaced;
                 return ret;
+        } else if (property == config->prop_out_fence_ptr) {
+                s64 __user *fence_ptr = u64_to_user_ptr(val);
+
+                if (!fence_ptr)
+                        return 0;
+
+                if (put_user(-1, fence_ptr))
+                        return -EFAULT;
+
+                set_out_fence_for_crtc(state->state, crtc, fence_ptr);
         } else if (crtc->funcs->atomic_set_property)
                 return crtc->funcs->atomic_set_property(crtc, state, property, val);
         else
@@ -536,6 +563,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
                 *val = (state->ctm) ? state->ctm->base.id : 0;
         else if (property == config->gamma_lut_property)
                 *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
+        else if (property == config->prop_out_fence_ptr)
+                *val = 0;
         else if (crtc->funcs->atomic_get_property)
                 return crtc->funcs->atomic_get_property(crtc, state, property, val);
         else
@@ -1664,11 +1693,9 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
  */
 
 static struct drm_pending_vblank_event *create_vblank_event(
-                struct drm_device *dev, struct drm_file *file_priv,
-                struct dma_fence *fence, uint64_t user_data)
+                struct drm_device *dev, uint64_t user_data)
 {
         struct drm_pending_vblank_event *e = NULL;
-        int ret;
 
         e = kzalloc(sizeof *e, GFP_KERNEL);
         if (!e)
@@ -1678,17 +1705,6 @@ static struct drm_pending_vblank_event *create_vblank_event(
         e->event.base.length = sizeof(e->event);
         e->event.user_data = user_data;
 
-        if (file_priv) {
-                ret = drm_event_reserve_init(dev, file_priv, &e->base,
-                                             &e->event.base);
-                if (ret) {
-                        kfree(e);
-                        return NULL;
-                }
-        }
-
-        e->base.fence = fence;
-
         return e;
 }
 
@@ -1793,6 +1809,165 @@ void drm_atomic_clean_old_fb(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_clean_old_fb);
 
+static struct dma_fence *get_crtc_fence(struct drm_crtc *crtc)
+{
+        struct dma_fence *fence;
+
+        fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+        if (!fence)
+                return NULL;
+
+        dma_fence_init(fence, &drm_crtc_fence_ops, &crtc->fence_lock,
+                       crtc->fence_context, ++crtc->fence_seqno);
+
+        return fence;
+}
+
+struct drm_out_fence_state {
+        s64 __user *out_fence_ptr;
+        struct sync_file *sync_file;
+        int fd;
+};
+
+static int setup_out_fence(struct drm_out_fence_state *fence_state,
+                           struct dma_fence *fence)
+{
+        fence_state->fd = get_unused_fd_flags(O_CLOEXEC);
+        if (fence_state->fd < 0)
+                return fence_state->fd;
+
+        if (put_user(fence_state->fd, fence_state->out_fence_ptr))
+                return -EFAULT;
+
+        fence_state->sync_file = sync_file_create(fence);
+        if (!fence_state->sync_file)
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int prepare_crtc_signaling(struct drm_device *dev,
+                                  struct drm_atomic_state *state,
+                                  struct drm_mode_atomic *arg,
+                                  struct drm_file *file_priv,
+                                  struct drm_out_fence_state **fence_state,
+                                  unsigned int *num_fences)
+{
+        struct drm_crtc *crtc;
+        struct drm_crtc_state *crtc_state;
+        int i, ret;
+
+        if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
+                return 0;
+
+        for_each_crtc_in_state(state, crtc, crtc_state, i) {
+                u64 __user *fence_ptr;
+
+                fence_ptr = get_out_fence_for_crtc(crtc_state->state, crtc);
+
+                if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT || fence_ptr) {
+                        struct drm_pending_vblank_event *e;
+
+                        e = create_vblank_event(dev, arg->user_data);
+                        if (!e)
+                                return -ENOMEM;
+
+                        crtc_state->event = e;
+                }
+
+                if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
+                        struct drm_pending_vblank_event *e = crtc_state->event;
+
+                        if (!file_priv)
+                                continue;
+
+                        ret = drm_event_reserve_init(dev, file_priv, &e->base,
+                                                     &e->event.base);
+                        if (ret) {
+                                kfree(e);
+                                crtc_state->event = NULL;
+                                return ret;
+                        }
+                }
+
+                if (fence_ptr) {
+                        struct dma_fence *fence;
+                        struct drm_out_fence_state *f;
+
+                        f = krealloc(*fence_state, sizeof(**fence_state) *
+                                     (*num_fences + 1), GFP_KERNEL);
+                        if (!f)
+                                return -ENOMEM;
+
+                        memset(&f[*num_fences], 0, sizeof(*f));
+
+                        f[*num_fences].out_fence_ptr = fence_ptr;
+                        *fence_state = f;
+
+                        fence = get_crtc_fence(crtc);
+                        if (!fence)
+                                return -ENOMEM;
+
+                        ret = setup_out_fence(&f[(*num_fences)++], fence);
+                        if (ret) {
+                                dma_fence_put(fence);
+                                return ret;
+                        }
+
+                        crtc_state->event->base.fence = fence;
+                }
+        }
+
+        return 0;
+}
+
+static void complete_crtc_signaling(struct drm_device *dev,
+                                    struct drm_atomic_state *state,
+                                    struct drm_out_fence_state *fence_state,
+                                    unsigned int num_fences,
+                                    bool install_fds)
+{
+        struct drm_crtc *crtc;
+        struct drm_crtc_state *crtc_state;
+        int i;
+
+        if (install_fds) {
+                for (i = 0; i < num_fences; i++)
+                        fd_install(fence_state[i].fd,
+                                   fence_state[i].sync_file->file);
+
+                kfree(fence_state);
+                return;
+        }
+
+        for_each_crtc_in_state(state, crtc, crtc_state, i) {
+                /*
+                 * TEST_ONLY and PAGE_FLIP_EVENT are mutually
+                 * exclusive, if they weren't, this code should be
+                 * called on success for TEST_ONLY too.
+                 */
+                if (crtc_state->event)
+                        drm_event_cancel_free(dev, &crtc_state->event->base);
+        }
+
+        if (!fence_state)
+                return;
+
+        for (i = 0; i < num_fences; i++) {
+                if (fence_state[i].sync_file)
+                        fput(fence_state[i].sync_file->file);
+                if (fence_state[i].fd >= 0)
+                        put_unused_fd(fence_state[i].fd);
+
+                /* If this fails log error to the user */
+                if (fence_state[i].out_fence_ptr &&
+                    put_user(-1, fence_state[i].out_fence_ptr))
+                        DRM_DEBUG_ATOMIC("Couldn't clear out_fence_ptr\n");
+        }
+
+        kfree(fence_state);
+}
+
 int drm_mode_atomic_ioctl(struct drm_device *dev,
                           void *data, struct drm_file *file_priv)
 {
@@ -1805,11 +1980,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
         struct drm_atomic_state *state;
         struct drm_modeset_acquire_ctx ctx;
         struct drm_plane *plane;
-        struct drm_crtc *crtc;
-        struct drm_crtc_state *crtc_state;
+        struct drm_out_fence_state *fence_state = NULL;
         unsigned plane_mask;
         int ret = 0;
-        unsigned int i, j;
+        unsigned int i, j, num_fences = 0;
 
         /* disallow for drivers not supporting atomic: */
         if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1924,20 +2098,10 @@ retry:
                 drm_mode_object_unreference(obj);
         }
 
-        if (arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-                for_each_crtc_in_state(state, crtc, crtc_state, i) {
-                        struct drm_pending_vblank_event *e;
-
-                        e = create_vblank_event(dev, file_priv, NULL,
-                                                arg->user_data);
-                        if (!e) {
-                                ret = -ENOMEM;
-                                goto out;
-                        }
-
-                        crtc_state->event = e;
-                }
-        }
+        ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
+                                     &num_fences);
+        if (ret)
+                goto out;
 
         if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY) {
                 /*
@@ -1957,20 +2121,7 @@ retry:
 out:
         drm_atomic_clean_old_fb(dev, plane_mask, ret);
 
-        if (ret && arg->flags & DRM_MODE_PAGE_FLIP_EVENT) {
-                /*
-                 * TEST_ONLY and PAGE_FLIP_EVENT are mutually exclusive,
-                 * if they weren't, this code should be called on success
-                 * for TEST_ONLY too.
-                 */
-
-                for_each_crtc_in_state(state, crtc, crtc_state, i) {
-                        if (!crtc_state->event)
-                                continue;
-
-                        drm_event_cancel_free(dev, &crtc_state->event->base);
-                }
-        }
+        complete_crtc_signaling(dev, state, fence_state, num_fences, !ret);
 
         if (ret == -EDEADLK) {
                 drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index dbfae422241e..90931e039731 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -267,6 +267,8 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
         if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
                 drm_object_attach_property(&crtc->base, config->prop_active, 0);
                 drm_object_attach_property(&crtc->base, config->prop_mode_id, 0);
+                drm_object_attach_property(&crtc->base,
+                                           config->prop_out_fence_ptr, 0);
         }
 
         return 0;
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 8bee2addf7b4..2735a5847ffa 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -314,6 +314,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
                 return -ENOMEM;
         dev->mode_config.prop_in_fence_fd = prop;
 
+        prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+                        "OUT_FENCE_PTR", 0, U64_MAX);
+        if (!prop)
+                return -ENOMEM;
+        dev->mode_config.prop_out_fence_ptr = prop;
+
         prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
                         "CRTC_ID", DRM_MODE_OBJECT_CRTC);
         if (!prop)
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 331bb100b718..c0eaec70a203 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -144,6 +144,7 @@ struct __drm_crtcs_state {
         struct drm_crtc *ptr;
         struct drm_crtc_state *state;
         struct drm_crtc_commit *commit;
+        s64 __user *out_fence_ptr;
 };
 
 struct __drm_connnectors_state {
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index c6754ccefe2b..bf9991b20611 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -486,6 +486,12 @@ struct drm_mode_config {
          */
         struct drm_property *prop_in_fence_fd;
         /**
+         * @prop_out_fence_ptr: Sync File fd pointer representing the
+         * outgoing fences for a CRTC. Userspace should provide a pointer to a
+         * value of type s64, and then cast that pointer to u64.
+         */
+        struct drm_property *prop_out_fence_ptr;
+        /**
          * @prop_crtc_id: Default atomic plane property to specify the
          * &drm_crtc.
          */