Commit b13cc8dd authored by Brian Starkey's avatar Brian Starkey Committed by Liviu Dudau

drm: writeback: Add out-fences for writeback connectors

Add the WRITEBACK_OUT_FENCE_PTR property to writeback connectors, to
enable userspace to get a fence which will signal once the writeback is
complete. It is not allowed to request an out-fence without a
framebuffer attached to the connector.

A timeline is added to drm_writeback_connector for use by the writeback
out-fences.

In the case of a commit failure or DRM_MODE_ATOMIC_TEST_ONLY, the fence
is set to -1.

Changes from v2:
 - Rebase onto Gustavo Padovan's v9 explicit sync series
 - Change out_fence_ptr type to s32 __user *
 - Set *out_fence_ptr to -1 in drm_atomic_connector_set_property
 - Store fence in drm_writeback_job
 Gustavo Padovan:
 - Move out_fence_ptr out of connector_state
 - Signal fence from drm_writeback_signal_completion instead of
   in driver directly

Changes from v3:
 - Rebase onto commit 7e9081c5 ("drm/fence: fix memory overwrite
   when setting out_fence fd") (change out_fence_ptr to s32 __user *,
   for real this time.)
 - Update documentation around WRITEBACK_OUT_FENCE_PTR
Signed-off-by: default avatarBrian Starkey <brian.starkey@arm.com>
[rebased and fixed conflicts]
Signed-off-by: default avatarMihail Atanassov <mihail.atanassov@arm.com>
Signed-off-by: default avatarLiviu Dudau <liviu.dudau@arm.com>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/229036/
parent 935774cd
......@@ -318,6 +318,35 @@ static s32 __user *get_out_fence_for_crtc(struct drm_atomic_state *state,
return fence_ptr;
}
static int set_out_fence_for_connector(struct drm_atomic_state *state,
struct drm_connector *connector,
s32 __user *fence_ptr)
{
unsigned int index = drm_connector_index(connector);
if (!fence_ptr)
return 0;
if (put_user(-1, fence_ptr))
return -EFAULT;
state->connectors[index].out_fence_ptr = fence_ptr;
return 0;
}
static s32 __user *get_out_fence_for_connector(struct drm_atomic_state *state,
struct drm_connector *connector)
{
unsigned int index = drm_connector_index(connector);
s32 __user *fence_ptr;
fence_ptr = state->connectors[index].out_fence_ptr;
state->connectors[index].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
......@@ -727,6 +756,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
return -EINVAL;
}
if (writeback_job->out_fence && !writeback_job->fb) {
DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
connector->base.id, connector->name);
return -EINVAL;
}
return 0;
}
......@@ -1367,6 +1402,11 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
if (fb)
drm_framebuffer_put(fb);
return ret;
} else if (property == config->writeback_out_fence_ptr_property) {
s32 __user *fence_ptr = u64_to_user_ptr(val);
return set_out_fence_for_connector(state->state, connector,
fence_ptr);
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
......@@ -1456,6 +1496,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
} else if (property == config->writeback_fb_id_property) {
/* Writeback framebuffer is one-shot, write and forget */
*val = 0;
} else if (property == config->writeback_out_fence_ptr_property) {
*val = 0;
} else if (connector->funcs->atomic_get_property) {
return connector->funcs->atomic_get_property(connector,
state, property, val);
......@@ -2292,7 +2334,7 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
return 0;
}
static int prepare_crtc_signaling(struct drm_device *dev,
static int prepare_signaling(struct drm_device *dev,
struct drm_atomic_state *state,
struct drm_mode_atomic *arg,
struct drm_file *file_priv,
......@@ -2301,6 +2343,8 @@ static int prepare_crtc_signaling(struct drm_device *dev,
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
struct drm_connector *conn;
struct drm_connector_state *conn_state;
int i, c = 0, ret;
if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
......@@ -2366,6 +2410,43 @@ static int prepare_crtc_signaling(struct drm_device *dev,
c++;
}
for_each_new_connector_in_state(state, conn, conn_state, i) {
struct drm_writeback_job *job;
struct drm_out_fence_state *f;
struct dma_fence *fence;
s32 __user *fence_ptr;
fence_ptr = get_out_fence_for_connector(state, conn);
if (!fence_ptr)
continue;
job = drm_atomic_get_writeback_job(conn_state);
if (!job)
return -ENOMEM;
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 = drm_writeback_get_out_fence((struct drm_writeback_connector *)conn);
if (!fence)
return -ENOMEM;
ret = setup_out_fence(&f[(*num_fences)++], fence);
if (ret) {
dma_fence_put(fence);
return ret;
}
job->out_fence = fence;
}
/*
* Having this flag means user mode pends on event which will never
* reach due to lack of at least one CRTC for signaling
......@@ -2376,11 +2457,11 @@ static int prepare_crtc_signaling(struct drm_device *dev,
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)
static void complete_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;
......@@ -2550,8 +2631,8 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
drm_mode_object_put(obj);
}
ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
&num_fences);
ret = prepare_signaling(dev, state, arg, file_priv, &fence_state,
&num_fences);
if (ret)
goto out;
......@@ -2567,7 +2648,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
}
out:
complete_crtc_signaling(dev, state, fence_state, num_fences, !ret);
complete_signaling(dev, state, fence_state, num_fences, !ret);
if (ret == -EDEADLK) {
drm_atomic_state_clear(state);
......
......@@ -14,6 +14,7 @@
#include <drm/drm_property.h>
#include <drm/drm_writeback.h>
#include <drm/drmP.h>
#include <linux/dma-fence.h>
/**
* DOC: overview
......@@ -31,6 +32,16 @@
* framebuffer applies only to a single commit (see below). A framebuffer may
* not be attached while the CRTC is off.
*
* Unlike with planes, when a writeback framebuffer is removed by userspace DRM
* makes no attempt to remove it from active use by the connector. This is
* because no method is provided to abort a writeback operation, and in any
* case making a new commit whilst a writeback is ongoing is undefined (see
* WRITEBACK_OUT_FENCE_PTR below). As soon as the current writeback is finished,
* the framebuffer will automatically no longer be in active use. As it will
* also have already been removed from the framebuffer list, there will be no
* way for any userspace application to retrieve a reference to it in the
* intervening period.
*
* Writeback connectors have some additional properties, which userspace
* can use to query and control them:
*
......@@ -47,8 +58,54 @@
* data is an array of u32 DRM_FORMAT_* fourcc values.
* Userspace can use this blob to find out what pixel formats are supported
* by the connector's writeback engine.
*
* "WRITEBACK_OUT_FENCE_PTR":
* Userspace can use this property to provide a pointer for the kernel to
* fill with a sync_file file descriptor, which will signal once the
* writeback is finished. The value should be the address of a 32-bit
* signed integer, cast to a u64.
* Userspace should wait for this fence to signal before making another
* commit affecting any of the same CRTCs, Planes or Connectors.
* **Failure to do so will result in undefined behaviour.**
* For this reason it is strongly recommended that all userspace
* applications making use of writeback connectors *always* retrieve an
* out-fence for the commit and use it appropriately.
* From userspace, this property will always read as zero.
*/
#define fence_to_wb_connector(x) container_of(x->lock, \
struct drm_writeback_connector, \
fence_lock)
static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence)
{
struct drm_writeback_connector *wb_connector =
fence_to_wb_connector(fence);
return wb_connector->base.dev->driver->name;
}
static const char *
drm_writeback_fence_get_timeline_name(struct dma_fence *fence)
{
struct drm_writeback_connector *wb_connector =
fence_to_wb_connector(fence);
return wb_connector->timeline_name;
}
static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence)
{
return true;
}
static const struct dma_fence_ops drm_writeback_fence_ops = {
.get_driver_name = drm_writeback_fence_get_driver_name,
.get_timeline_name = drm_writeback_fence_get_timeline_name,
.enable_signaling = drm_writeback_fence_enable_signaling,
.wait = dma_fence_default_wait,
};
static int create_writeback_properties(struct drm_device *dev)
{
struct drm_property *prop;
......@@ -72,6 +129,15 @@ static int create_writeback_properties(struct drm_device *dev)
dev->mode_config.writeback_pixel_formats_property = prop;
}
if (!dev->mode_config.writeback_out_fence_ptr_property) {
prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
"WRITEBACK_OUT_FENCE_PTR", 0,
U64_MAX);
if (!prop)
return -ENOMEM;
dev->mode_config.writeback_out_fence_ptr_property = prop;
}
return 0;
}
......@@ -141,6 +207,15 @@ int drm_writeback_connector_init(struct drm_device *dev,
INIT_LIST_HEAD(&wb_connector->job_queue);
spin_lock_init(&wb_connector->job_lock);
wb_connector->fence_context = dma_fence_context_alloc(1);
spin_lock_init(&wb_connector->fence_lock);
snprintf(wb_connector->timeline_name,
sizeof(wb_connector->timeline_name),
"CONNECTOR:%d-%s", connector->base.id, connector->name);
drm_object_attach_property(&connector->base,
config->writeback_out_fence_ptr_property, 0);
drm_object_attach_property(&connector->base,
config->writeback_fb_id_property, 0);
......@@ -210,6 +285,7 @@ static void cleanup_work(struct work_struct *work)
/**
* drm_writeback_signal_completion - Signal the completion of a writeback job
* @wb_connector: The writeback connector whose job is complete
* @status: Status code to set in the writeback out_fence (0 for success)
*
* Drivers should call this to signal the completion of a previously queued
* writeback job. It should be called as soon as possible after the hardware
......@@ -223,7 +299,8 @@ static void cleanup_work(struct work_struct *work)
* See also: drm_writeback_queue_job()
*/
void
drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
int status)
{
unsigned long flags;
struct drm_writeback_job *job;
......@@ -232,8 +309,15 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
job = list_first_entry_or_null(&wb_connector->job_queue,
struct drm_writeback_job,
list_entry);
if (job)
if (job) {
list_del(&job->list_entry);
if (job->out_fence) {
if (status)
dma_fence_set_error(job->out_fence, status);
dma_fence_signal(job->out_fence);
dma_fence_put(job->out_fence);
}
}
spin_unlock_irqrestore(&wb_connector->job_lock, flags);
if (WARN_ON(!job))
......@@ -243,3 +327,24 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
queue_work(system_long_wq, &job->cleanup_work);
}
EXPORT_SYMBOL(drm_writeback_signal_completion);
struct dma_fence *
drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector)
{
struct dma_fence *fence;
if (WARN_ON(wb_connector->base.connector_type !=
DRM_MODE_CONNECTOR_WRITEBACK))
return NULL;
fence = kzalloc(sizeof(*fence), GFP_KERNEL);
if (!fence)
return NULL;
dma_fence_init(fence, &drm_writeback_fence_ops,
&wb_connector->fence_lock, wb_connector->fence_context,
++wb_connector->fence_seqno);
return fence;
}
EXPORT_SYMBOL(drm_writeback_get_out_fence);
......@@ -160,6 +160,14 @@ struct __drm_crtcs_state {
struct __drm_connnectors_state {
struct drm_connector *ptr;
struct drm_connector_state *state, *old_state, *new_state;
/**
* @out_fence_ptr:
*
* User-provided pointer which the kernel uses to return a sync_file
* file descriptor. Used by writeback connectors to signal completion of
* the writeback.
*/
s32 __user *out_fence_ptr;
};
struct drm_private_obj;
......
......@@ -441,10 +441,10 @@ struct drm_connector_state {
/**
* @writeback_job: Writeback job for writeback connectors
*
* Holds the framebuffer for a writeback connector. As the writeback
* completion may be asynchronous to the normal commit cycle, the
* writeback job lifetime is managed separately from the normal atomic
* state by this object.
* Holds the framebuffer and out-fence for a writeback connector. As
* the writeback completion may be asynchronous to the normal commit
* cycle, the writeback job lifetime is managed separately from the
* normal atomic state by this object.
*
* See also: drm_writeback_queue_job() and
* drm_writeback_signal_completion()
......
......@@ -798,6 +798,14 @@ struct drm_mode_config {
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_pixel_formats_property;
/**
* @writeback_out_fence_ptr_property: Property for writeback connectors,
* fd pointer representing the outgoing fences for a writeback
* connector. Userspace should provide a pointer to a value of type s32,
* and then cast that pointer to u64.
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_out_fence_ptr_property;
/* dumb ioctl parameters */
uint32_t preferred_depth, prefer_shadow;
......
......@@ -50,6 +50,32 @@ struct drm_writeback_connector {
* drm_writeback_signal_completion()
*/
struct list_head job_queue;
/**
* @fence_context:
*
* timeline context used for fence operations.
*/
unsigned int fence_context;
/**
* @fence_lock:
*
* spinlock to protect the fences in the fence_context.
*/
spinlock_t fence_lock;
/**
* @fence_seqno:
*
* Seqno variable used as monotonic counter for the fences
* created on the connector's timeline.
*/
unsigned long fence_seqno;
/**
* @timeline_name:
*
* The name of the connector's fence timeline.
*/
char timeline_name[32];
};
struct drm_writeback_job {
......@@ -75,6 +101,13 @@ struct drm_writeback_job {
* directly, use drm_atomic_set_writeback_fb_for_connector()
*/
struct drm_framebuffer *fb;
/**
* @out_fence:
*
* Fence which will signal once the writeback has completed
*/
struct dma_fence *out_fence;
};
int drm_writeback_connector_init(struct drm_device *dev,
......@@ -87,5 +120,11 @@ void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
struct drm_writeback_job *job);
void drm_writeback_cleanup_job(struct drm_writeback_job *job);
void drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector);
void
drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
int status);
struct dma_fence *
drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector);
#endif
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