| Message ID | 20170515172057.30315-2-Liviu.Dudau@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, May 15, 2017 at 1:20 PM, Liviu Dudau <Liviu.Dudau@arm.com> wrote: > From: Brian Starkey <brian.starkey@arm.com> > > Writeback connectors represent writeback engines which can write the > CRTC output to a memory framebuffer. Add a writeback connector type and > related support functions. > > Drivers should initialize a writeback connector with > drm_writeback_connector_init() which takes care of setting up all the > writeback-specific details on top of the normal functionality of > drm_connector_init(). > > Writeback connectors have a WRITEBACK_FB_ID property, used to set the > output framebuffer, and a WRITEBACK_PIXEL_FORMATS blob used to expose the > supported writeback formats to userspace. > > When a framebuffer is attached to a writeback connector with the > WRITEBACK_FB_ID property, it is used only once (for the commit in which > it was included), and userspace can never read back the value of > WRITEBACK_FB_ID. WRITEBACK_FB_ID can only be set if the connector is > attached to a CRTC. So one thought.. since rmfb is kinda horrible, I think rmfb/drm_framebuffer_remove() probably needs to fish out writeback connectors that are using the fb and disable them as well. BR, -R > Changes since v1: > - Added drm_writeback.c + documentation > - Added helper to initialize writeback connector in one go > - Added core checks > - Squashed into a single commit > - Dropped the client cap > - Writeback framebuffers are no longer persistent > > Changes since v2: > Daniel Vetter: > - Subclass drm_connector to drm_writeback_connector > - Relax check to allow CRTC to be set without an FB > - Add some writeback_ prefixes > - Drop PIXEL_FORMATS_SIZE property, as it was unnecessary > Gustavo Padovan: > - Add drm_writeback_job to handle writeback signalling centrally > > Changes since v3: > - Rebased > - Rename PIXEL_FORMATS -> WRITEBACK_PIXEL_FORMATS > > Chances since v4: > - Embed a drm_encoder inside the drm_writeback_connector to > reduce the amount of boilerplate code inside drivers using it. > > Signed-off-by: Brian Starkey <brian.starkey@arm.com> > [rebased and fixed conflicts] > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com> > Signed-off-by: Liviu Dudau <liviu.dudau@arm.com> > --- > Documentation/gpu/drm-kms.rst | 9 ++ > drivers/gpu/drm/Makefile | 2 +- > drivers/gpu/drm/drm_atomic.c | 130 ++++++++++++++++++ > drivers/gpu/drm/drm_atomic_helper.c | 6 + > drivers/gpu/drm/drm_connector.c | 4 +- > drivers/gpu/drm/drm_writeback.c | 257 ++++++++++++++++++++++++++++++++++++ > include/drm/drm_atomic.h | 3 + > include/drm/drm_connector.h | 13 ++ > include/drm/drm_mode_config.h | 14 ++ > include/drm/drm_writeback.h | 88 ++++++++++++ > include/uapi/drm/drm_mode.h | 1 + > 11 files changed, 525 insertions(+), 2 deletions(-) > create mode 100644 drivers/gpu/drm/drm_writeback.c > create mode 100644 include/drm/drm_writeback.h > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > index bfecd21a8cdf..7a8ef1a4fe17 100644 > --- a/Documentation/gpu/drm-kms.rst > +++ b/Documentation/gpu/drm-kms.rst > @@ -364,6 +364,15 @@ Connector Functions Reference > .. kernel-doc:: drivers/gpu/drm/drm_connector.c > :export: > > +Writeback Connectors > +-------------------- > + > +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c > + :doc: overview > + > +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c > + :export: > + > Encoder Abstraction > =================== > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 59f0f9b696eb..99ef500ae8b2 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -16,7 +16,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \ > drm_framebuffer.o drm_connector.o drm_blend.o \ > drm_encoder.o drm_mode_object.o drm_property.o \ > drm_plane.o drm_color_mgmt.o drm_print.o \ > - drm_dumb_buffers.o drm_mode_config.o > + drm_dumb_buffers.o drm_mode_config.o drm_writeback.o > > drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o > drm-$(CONFIG_DRM_VM) += drm_vm.o > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c > index f32506a7c1d6..317ae625b417 100644 > --- a/drivers/gpu/drm/drm_atomic.c > +++ b/drivers/gpu/drm/drm_atomic.c > @@ -31,6 +31,7 @@ > #include <drm/drm_mode.h> > #include <drm/drm_plane_helper.h> > #include <drm/drm_print.h> > +#include <drm/drm_writeback.h> > #include <linux/sync_file.h> > > #include "drm_crtc_internal.h" > @@ -654,6 +655,46 @@ static void drm_atomic_crtc_print_state(struct drm_printer *p, > } > > /** > + * drm_atomic_connector_check - check connector state > + * @connector: connector to check > + * @state: connector state to check > + * > + * Provides core sanity checks for connector state. > + * > + * RETURNS: > + * Zero on success, error code on failure > + */ > +static int drm_atomic_connector_check(struct drm_connector *connector, > + struct drm_connector_state *state) > +{ > + struct drm_crtc_state *crtc_state; > + struct drm_writeback_job *writeback_job = state->writeback_job; > + > + if ((connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK) || > + !writeback_job) > + return 0; > + > + if (writeback_job->fb && !state->crtc) { > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] framebuffer without CRTC\n", > + connector->base.id, connector->name); > + return -EINVAL; > + } > + > + if (state->crtc) > + crtc_state = drm_atomic_get_existing_crtc_state(state->state, > + state->crtc); > + > + if (writeback_job->fb && !crtc_state->active) { > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] has framebuffer, but [CRTC:%d] is off\n", > + connector->base.id, connector->name, > + state->crtc->base.id); > + return -EINVAL; > + } > + > + return 0; > +} > + > +/** > * drm_atomic_get_plane_state - get plane state > * @state: global atomic state object > * @plane: plane to get state object for > @@ -1123,6 +1164,12 @@ int drm_atomic_connector_set_property(struct drm_connector *connector, > */ > if (state->link_status != DRM_LINK_STATUS_GOOD) > state->link_status = val; > + } else if (property == config->writeback_fb_id_property) { > + struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, val); > + int ret = drm_atomic_set_writeback_fb_for_connector(state, fb); > + if (fb) > + drm_framebuffer_unreference(fb); > + return ret; > } else if (connector->funcs->atomic_set_property) { > return connector->funcs->atomic_set_property(connector, > state, property, val); > @@ -1199,6 +1246,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector, > *val = state->tv.hue; > } else if (property == config->link_status_property) { > *val = state->link_status; > + } else if (property == config->writeback_fb_id_property) { > + /* Writeback framebuffer is one-shot, write and forget */ > + *val = 0; > } else if (connector->funcs->atomic_get_property) { > return connector->funcs->atomic_get_property(connector, > state, property, val); > @@ -1406,6 +1456,75 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, > } > EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector); > > +/* > + * drm_atomic_get_writeback_job - return or allocate a writeback job > + * @conn_state: Connector state to get the job for > + * > + * Writeback jobs have a different lifetime to the atomic state they are > + * associated with. This convenience function takes care of allocating a job > + * if there isn't yet one associated with the connector state, otherwise > + * it just returns the existing job. > + * > + * Returns: The writeback job for the given connector state > + */ > +static struct drm_writeback_job * > +drm_atomic_get_writeback_job(struct drm_connector_state *conn_state) > +{ > + WARN_ON(conn_state->connector->connector_type != > + DRM_MODE_CONNECTOR_WRITEBACK); > + > + if (!conn_state->writeback_job) > + conn_state->writeback_job = > + kzalloc(sizeof(*conn_state->writeback_job), GFP_KERNEL); > + > + return conn_state->writeback_job; > +} > + > +/** > + * drm_atomic_set_writeback_fb_for_connector - set writeback framebuffer > + * @conn_state: atomic state object for the connector > + * @fb: fb to use for the connector > + * > + * This is used to set the framebuffer for a writeback connector, which outputs > + * to a buffer instead of an actual physical connector. > + * Changing the assigned framebuffer requires us to grab a reference to the new > + * fb and drop the reference to the old fb, if there is one. This function > + * takes care of all these details besides updating the pointer in the > + * state object itself. > + * > + * Note: The only way conn_state can already have an fb set is if the commit > + * sets the property more than once. > + * > + * See also: drm_writeback_connector_init() > + * > + * Returns: 0 on success > + */ > +int drm_atomic_set_writeback_fb_for_connector( > + struct drm_connector_state *conn_state, > + struct drm_framebuffer *fb) > +{ > + struct drm_writeback_job *job = > + drm_atomic_get_writeback_job(conn_state); > + if (!job) > + return -ENOMEM; > + > + if (job->fb) > + drm_framebuffer_unreference(job->fb); > + if (fb) > + drm_framebuffer_reference(fb); > + job->fb = fb; > + > + if (fb) > + DRM_DEBUG_ATOMIC("Set [FB:%d] for connector state %p\n", > + fb->base.id, conn_state); > + else > + DRM_DEBUG_ATOMIC("Set [NOFB] for connector state %p\n", > + conn_state); > + > + return 0; > +} > +EXPORT_SYMBOL(drm_atomic_set_writeback_fb_for_connector); > + > /** > * drm_atomic_add_affected_connectors - add connectors for crtc > * @state: atomic state > @@ -1556,6 +1675,8 @@ int drm_atomic_check_only(struct drm_atomic_state *state) > struct drm_plane_state *plane_state; > struct drm_crtc *crtc; > struct drm_crtc_state *crtc_state; > + struct drm_connector *conn; > + struct drm_connector_state *conn_state; > int i, ret = 0; > > DRM_DEBUG_ATOMIC("checking %p\n", state); > @@ -1578,6 +1699,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state) > } > } > > + for_each_connector_in_state(state, conn, conn_state, i) { > + ret = drm_atomic_connector_check(conn, conn_state); > + if (ret) { > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] atomic core check failed\n", > + conn->base.id, conn->name); > + return ret; > + } > + } > + > if (config->funcs->atomic_check) > ret = config->funcs->atomic_check(state->dev, state); > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 8be9719284b0..fa2d8d7a602a 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -30,6 +30,7 @@ > #include <drm/drm_plane_helper.h> > #include <drm/drm_crtc_helper.h> > #include <drm/drm_atomic_helper.h> > +#include <drm/drm_writeback.h> > #include <linux/dma-fence.h> > > #include "drm_crtc_internal.h" > @@ -3361,6 +3362,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector, > memcpy(state, connector->state, sizeof(*state)); > if (state->crtc) > drm_connector_get(connector); > + > + /* Don't copy over a writeback job, they are used only once */ > + state->writeback_job = NULL; > } > EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state); > > @@ -3487,6 +3491,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state) > { > if (state->crtc) > drm_connector_put(state->connector); > + if (state->writeback_job) > + drm_writeback_cleanup_job(state->writeback_job); > } > EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state); > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index 9f847615ac74..fb9ace3ef744 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -86,6 +86,7 @@ static struct drm_conn_prop_enum_list drm_connector_enum_list[] = { > { DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" }, > { DRM_MODE_CONNECTOR_DSI, "DSI" }, > { DRM_MODE_CONNECTOR_DPI, "DPI" }, > + { DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" }, > }; > > void drm_connector_ida_init(void) > @@ -222,7 +223,8 @@ int drm_connector_init(struct drm_device *dev, > config->num_connector++; > spin_unlock_irq(&config->connector_list_lock); > > - if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL) > + if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL && > + connector_type != DRM_MODE_CONNECTOR_WRITEBACK) > drm_object_attach_property(&connector->base, > config->edid_property, > 0); > diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c > new file mode 100644 > index 000000000000..48c8599e8248 > --- /dev/null > +++ b/drivers/gpu/drm/drm_writeback.c > @@ -0,0 +1,257 @@ > +/* > + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. > + * Author: Brian Starkey <brian.starkey@arm.com> > + * > + * This program is free software and is provided to you under the terms of the > + * GNU General Public License version 2 as published by the Free Software > + * Foundation, and any use by you of this program is subject to the terms > + * of such GNU licence. > + */ > + > +#include <drm/drm_crtc.h> > +#include <drm/drm_modeset_helper_vtables.h> > +#include <drm/drm_property.h> > +#include <drm/drm_writeback.h> > +#include <drm/drmP.h> > + > +/** > + * DOC: overview > + * > + * Writeback connectors are used to expose hardware which can write the output > + * from a CRTC to a memory buffer. They are used and act similarly to other > + * types of connectors, with some important differences: > + * - Writeback connectors don't provide a way to output visually to the user. > + * - Writeback connectors should always report as "disconnected" (so that > + * clients which don't understand them will ignore them). > + * - Writeback connectors don't have EDID. > + * > + * A framebuffer may only be attached to a writeback connector when the > + * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the > + * framebuffer applies only to a single commit (see below). A framebuffer may > + * not be attached while the CRTC is off. > + * > + * Writeback connectors have some additional properties, which userspace > + * can use to query and control them: > + * > + * "WRITEBACK_FB_ID": > + * Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the > + * framebuffer to be written by the writeback connector. This property is > + * similar to the FB_ID property on planes, but will always read as zero > + * and is not preserved across commits. > + * Userspace must set this property to an output buffer every time it > + * wishes the buffer to get filled. > + * > + * "WRITEBACK_PIXEL_FORMATS": > + * Immutable blob property to store the supported pixel formats table. The > + * 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. > + */ > + > +static bool create_writeback_properties(struct drm_device *dev) > +{ > + struct drm_property *prop; > + > + if (!dev->mode_config.writeback_fb_id_property) { > + prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, > + "WRITEBACK_FB_ID", > + DRM_MODE_OBJECT_FB); > + if (!prop) > + return false; > + dev->mode_config.writeback_fb_id_property = prop; > + } > + > + if (!dev->mode_config.writeback_pixel_formats_property) { > + prop = drm_property_create(dev, DRM_MODE_PROP_BLOB | DRM_MODE_PROP_IMMUTABLE, > + "WRITEBACK_PIXEL_FORMATS", 0); > + if (!prop) > + return false; > + dev->mode_config.writeback_pixel_formats_property = prop; > + } > + > + return true; > +} > + > +static const struct drm_encoder_funcs drm_writeback_encoder_funcs = { > + .destroy = drm_encoder_cleanup, > +}; > + > +/** > + * drm_writeback_connector_init - Initialize a writeback connector and its properties > + * @dev: DRM device > + * @wb_connector: Writeback connector to initialize > + * @con_funcs: Connector funcs vtable > + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder > + * @formats: Array of supported pixel formats for the writeback engine > + * @n_formats: Length of the formats array > + * > + * This function creates the writeback-connector-specific properties if they > + * have not been already created, initializes the connector as > + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property > + * values. It will also create an internal encoder associated with the > + * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for > + * the encoder helper. > + * > + * Drivers should always use this function instead of drm_connector_init() to > + * set up writeback connectors. > + * > + * Returns: 0 on success, or a negative error code > + */ > +int drm_writeback_connector_init(struct drm_device *dev, > + struct drm_writeback_connector *wb_connector, > + const struct drm_connector_funcs *con_funcs, > + const struct drm_encoder_helper_funcs *enc_helper_funcs, > + const u32 *formats, int n_formats) > +{ > + int ret; > + struct drm_property_blob *blob; > + struct drm_connector *connector = &wb_connector->base; > + struct drm_mode_config *config = &dev->mode_config; > + > + if (!create_writeback_properties(dev)) > + return -EINVAL; > + > + blob = drm_property_create_blob(dev, n_formats * sizeof(*formats), > + formats); > + if (IS_ERR(blob)) > + return PTR_ERR(blob); > + > + drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs); > + ret = drm_encoder_init(dev, &wb_connector->encoder, > + &drm_writeback_encoder_funcs, > + DRM_MODE_ENCODER_VIRTUAL, NULL); > + if (ret) > + goto fail; > + > + connector->interlace_allowed = 0; > + > + ret = drm_connector_init(dev, connector, con_funcs, > + DRM_MODE_CONNECTOR_WRITEBACK); > + if (ret) > + goto connector_fail; > + > + ret = drm_mode_connector_attach_encoder(connector, > + &wb_connector->encoder); > + if (ret) > + goto attach_fail; > + > + INIT_LIST_HEAD(&wb_connector->job_queue); > + spin_lock_init(&wb_connector->job_lock); > + > + drm_object_attach_property(&connector->base, > + config->writeback_fb_id_property, 0); > + > + drm_object_attach_property(&connector->base, > + config->writeback_pixel_formats_property, > + blob->base.id); > + wb_connector->pixel_formats_blob_ptr = blob; > + > + return 0; > + > +attach_fail: > + drm_connector_cleanup(connector); > +connector_fail: > + drm_encoder_cleanup(&wb_connector->encoder); > +fail: > + drm_property_unreference_blob(blob); > + return ret; > +} > +EXPORT_SYMBOL(drm_writeback_connector_init); > + > +/** > + * @drm_writeback_queue_job: Queue a writeback job for later signalling > + * @wb_connector: The writeback connector to queue a job on > + * @job: The job to queue > + * > + * This function adds a job to the job_queue for a writeback connector. It > + * should be considered to take ownership of the writeback job, and so any other > + * references to the job must be cleared after calling this function. > + * > + * Drivers must ensure that for a given writeback connector, jobs are queued in > + * exactly the same order as they will be completed by the hardware (and > + * signaled via drm_writeback_signal_completion). > + * > + * For every call to drm_writeback_queue_job() there must be exactly one call to > + * drm_writeback_signal_completion() > + * > + * See also: drm_writeback_signal_completion() > + */ > +void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector, > + struct drm_writeback_job *job) > +{ > + unsigned long flags; > + > + spin_lock_irqsave(&wb_connector->job_lock, flags); > + list_add_tail(&job->list_entry, &wb_connector->job_queue); > + spin_unlock_irqrestore(&wb_connector->job_lock, flags); > +} > +EXPORT_SYMBOL(drm_writeback_queue_job); > + > +/** > + * @drm_writeback_cleanup_job: Cleanup and free a writeback job > + * @job: The writeback job to free > + * > + * Drops any references held by the writeback job, and frees the structure. > + */ > +void drm_writeback_cleanup_job(struct drm_writeback_job *job) > +{ > + if (!job) > + return; > + > + if (job->fb) > + drm_framebuffer_unreference(job->fb); > + kfree(job); > +} > +EXPORT_SYMBOL(drm_writeback_cleanup_job); > + > +/* > + * @cleanup_work: deferred cleanup of a writeback job > + * > + * The job cannot be cleaned up directly in drm_writeback_signal_completion, > + * because it may be called in interrupt context. Dropping the framebuffer > + * reference can sleep, and so the cleanup is deferred to a workqueue. > + */ > +static void cleanup_work(struct work_struct *work) > +{ > + struct drm_writeback_job *job = container_of(work, > + struct drm_writeback_job, > + cleanup_work); > + drm_writeback_cleanup_job(job); > +} > + > +/** > + * @drm_writeback_signal_completion: Signal the completion of a writeback job > + * @wb_connector: The writeback connector whose job is complete > + * > + * 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 > + * has finished writing, and may be called from interrupt context. > + * It is the driver's responsibility to ensure that for a given connector, the > + * hardware completes writeback jobs in the same order as they are queued. > + * > + * Unless the driver is holding its own reference to the framebuffer, it must > + * not be accessed after calling this function. > + * > + * See also: drm_writeback_queue_job() > + */ > +void > +drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) > +{ > + unsigned long flags; > + struct drm_writeback_job *job; > + > + spin_lock_irqsave(&wb_connector->job_lock, flags); > + job = list_first_entry_or_null(&wb_connector->job_queue, > + struct drm_writeback_job, > + list_entry); > + if (job) > + list_del(&job->list_entry); > + spin_unlock_irqrestore(&wb_connector->job_lock, flags); > + > + if (WARN_ON(!job)) > + return; > + > + INIT_WORK(&job->cleanup_work, cleanup_work); > + queue_work(system_long_wq, &job->cleanup_work); > +} > +EXPORT_SYMBOL(drm_writeback_signal_completion); > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h > index 788daf756f48..183b7c60adab 100644 > --- a/include/drm/drm_atomic.h > +++ b/include/drm/drm_atomic.h > @@ -478,6 +478,9 @@ void drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state, > int __must_check > drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, > struct drm_crtc *crtc); > +int drm_atomic_set_writeback_fb_for_connector( > + struct drm_connector_state *conn_state, > + struct drm_framebuffer *fb); > int __must_check > drm_atomic_add_affected_connectors(struct drm_atomic_state *state, > struct drm_crtc *crtc); > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index 4eeda120e46d..c97a4729c071 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -326,6 +326,19 @@ struct drm_connector_state { > struct drm_atomic_state *state; > > struct drm_tv_connector_state tv; > + > + /** > + * @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. > + * > + * See also: drm_writeback_queue_job() and > + * drm_writeback_signal_completion() > + */ > + struct drm_writeback_job *writeback_job; > }; > > /** > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index 42981711189b..cbc1b2998085 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -741,6 +741,20 @@ struct drm_mode_config { > */ > struct drm_property *suggested_y_property; > > + /** > + * @writeback_fb_id_property: Property for writeback connectors, storing > + * the ID of the output framebuffer. > + * See also: drm_writeback_connector_init() > + */ > + struct drm_property *writeback_fb_id_property; > + /** > + * @writeback_pixel_formats_property: Property for writeback connectors, > + * storing an array of the supported pixel formats for the writeback > + * engine (read-only). > + * See also: drm_writeback_connector_init() > + */ > + struct drm_property *writeback_pixel_formats_property; > + > /* dumb ioctl parameters */ > uint32_t preferred_depth, prefer_shadow; > > diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h > new file mode 100644 > index 000000000000..cf3a28676006 > --- /dev/null > +++ b/include/drm/drm_writeback.h > @@ -0,0 +1,88 @@ > +/* > + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. > + * Author: Brian Starkey <brian.starkey@arm.com> > + * > + * This program is free software and is provided to you under the terms of the > + * GNU General Public License version 2 as published by the Free Software > + * Foundation, and any use by you of this program is subject to the terms > + * of such GNU licence. > + */ > + > +#ifndef __DRM_WRITEBACK_H__ > +#define __DRM_WRITEBACK_H__ > +#include <drm/drm_connector.h> > +#include <drm/drm_encoder.h> > +#include <linux/workqueue.h> > + > +struct drm_writeback_connector { > + struct drm_connector base; > + > + /** > + * @encoder: Internal encoder used by the connector to fulfill > + * the DRM framework requirements. The users of the > + * @drm_writeback_connector control the behaviour of the @encoder > + * by passing the @enc_funcs parameter to drm_writeback_connector_init() > + * function. > + */ > + struct drm_encoder encoder; > + > + /** > + * @pixel_formats_blob_ptr: > + * > + * DRM blob property data for the pixel formats list on writeback > + * connectors > + * See also drm_writeback_connector_init() > + */ > + struct drm_property_blob *pixel_formats_blob_ptr; > + > + /** @job_lock: Protects job_queue */ > + spinlock_t job_lock; > + > + /** > + * @job_queue: > + * > + * Holds a list of a connector's writeback jobs; the last item is the > + * most recent. The first item may be either waiting for the hardware > + * to begin writing, or currently being written. > + * > + * See also: drm_writeback_queue_job() and > + * drm_writeback_signal_completion() > + */ > + struct list_head job_queue; > +}; > + > +struct drm_writeback_job { > + /** > + * @cleanup_work: > + * > + * Used to allow drm_writeback_signal_completion to defer dropping the > + * framebuffer reference to a workqueue. > + */ > + struct work_struct cleanup_work; > + /** > + * @list_entry: > + * > + * List item for the connector's @job_queue > + */ > + struct list_head list_entry; > + /** > + * @fb: > + * > + * Framebuffer to be written to by the writeback connector. Do not set > + * directly, use drm_atomic_set_writeback_fb_for_connector() > + */ > + struct drm_framebuffer *fb; > +}; > + > +int drm_writeback_connector_init(struct drm_device *dev, > + struct drm_writeback_connector *wb_connector, > + const struct drm_connector_funcs *con_funcs, > + const struct drm_encoder_helper_funcs *enc_helper_funcs, > + const u32 *formats, int n_formats); > + > +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); > +#endif > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > index 8c67fc03d53d..686ae5599c22 100644 > --- a/include/uapi/drm/drm_mode.h > +++ b/include/uapi/drm/drm_mode.h > @@ -269,6 +269,7 @@ enum drm_mode_subconnector { > #define DRM_MODE_CONNECTOR_VIRTUAL 15 > #define DRM_MODE_CONNECTOR_DSI 16 > #define DRM_MODE_CONNECTOR_DPI 17 > +#define DRM_MODE_CONNECTOR_WRITEBACK 18 > > struct drm_mode_get_connector { > > -- > 2.12.2 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Mon, May 15, 2017 at 08:30:13PM -0400, Rob Clark wrote: > On Mon, May 15, 2017 at 1:20 PM, Liviu Dudau <Liviu.Dudau@arm.com> wrote: > > From: Brian Starkey <brian.starkey@arm.com> > > > > Writeback connectors represent writeback engines which can write the > > CRTC output to a memory framebuffer. Add a writeback connector type and > > related support functions. > > > > Drivers should initialize a writeback connector with > > drm_writeback_connector_init() which takes care of setting up all the > > writeback-specific details on top of the normal functionality of > > drm_connector_init(). > > > > Writeback connectors have a WRITEBACK_FB_ID property, used to set the > > output framebuffer, and a WRITEBACK_PIXEL_FORMATS blob used to expose the > > supported writeback formats to userspace. > > > > When a framebuffer is attached to a writeback connector with the > > WRITEBACK_FB_ID property, it is used only once (for the commit in which > > it was included), and userspace can never read back the value of > > WRITEBACK_FB_ID. WRITEBACK_FB_ID can only be set if the connector is > > attached to a CRTC. > > So one thought.. since rmfb is kinda horrible, I think > rmfb/drm_framebuffer_remove() probably needs to fish out writeback > connectors that are using the fb and disable them as well. Yes, that is a good idea. Will do it in v6. Thanks for looking over this. Best regards, Liviu > > BR, > -R > > > > Changes since v1: > > - Added drm_writeback.c + documentation > > - Added helper to initialize writeback connector in one go > > - Added core checks > > - Squashed into a single commit > > - Dropped the client cap > > - Writeback framebuffers are no longer persistent > > > > Changes since v2: > > Daniel Vetter: > > - Subclass drm_connector to drm_writeback_connector > > - Relax check to allow CRTC to be set without an FB > > - Add some writeback_ prefixes > > - Drop PIXEL_FORMATS_SIZE property, as it was unnecessary > > Gustavo Padovan: > > - Add drm_writeback_job to handle writeback signalling centrally > > > > Changes since v3: > > - Rebased > > - Rename PIXEL_FORMATS -> WRITEBACK_PIXEL_FORMATS > > > > Chances since v4: > > - Embed a drm_encoder inside the drm_writeback_connector to > > reduce the amount of boilerplate code inside drivers using it. > > > > Signed-off-by: Brian Starkey <brian.starkey@arm.com> > > [rebased and fixed conflicts] > > Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com> > > Signed-off-by: Liviu Dudau <liviu.dudau@arm.com> > > --- > > Documentation/gpu/drm-kms.rst | 9 ++ > > drivers/gpu/drm/Makefile | 2 +- > > drivers/gpu/drm/drm_atomic.c | 130 ++++++++++++++++++ > > drivers/gpu/drm/drm_atomic_helper.c | 6 + > > drivers/gpu/drm/drm_connector.c | 4 +- > > drivers/gpu/drm/drm_writeback.c | 257 ++++++++++++++++++++++++++++++++++++ > > include/drm/drm_atomic.h | 3 + > > include/drm/drm_connector.h | 13 ++ > > include/drm/drm_mode_config.h | 14 ++ > > include/drm/drm_writeback.h | 88 ++++++++++++ > > include/uapi/drm/drm_mode.h | 1 + > > 11 files changed, 525 insertions(+), 2 deletions(-) > > create mode 100644 drivers/gpu/drm/drm_writeback.c > > create mode 100644 include/drm/drm_writeback.h > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > index bfecd21a8cdf..7a8ef1a4fe17 100644 > > --- a/Documentation/gpu/drm-kms.rst > > +++ b/Documentation/gpu/drm-kms.rst > > @@ -364,6 +364,15 @@ Connector Functions Reference > > .. kernel-doc:: drivers/gpu/drm/drm_connector.c > > :export: > > > > +Writeback Connectors > > +-------------------- > > + > > +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c > > + :doc: overview > > + > > +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c > > + :export: > > + > > Encoder Abstraction > > =================== > > > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > > index 59f0f9b696eb..99ef500ae8b2 100644 > > --- a/drivers/gpu/drm/Makefile > > +++ b/drivers/gpu/drm/Makefile > > @@ -16,7 +16,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \ > > drm_framebuffer.o drm_connector.o drm_blend.o \ > > drm_encoder.o drm_mode_object.o drm_property.o \ > > drm_plane.o drm_color_mgmt.o drm_print.o \ > > - drm_dumb_buffers.o drm_mode_config.o > > + drm_dumb_buffers.o drm_mode_config.o drm_writeback.o > > > > drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o > > drm-$(CONFIG_DRM_VM) += drm_vm.o > > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c > > index f32506a7c1d6..317ae625b417 100644 > > --- a/drivers/gpu/drm/drm_atomic.c > > +++ b/drivers/gpu/drm/drm_atomic.c > > @@ -31,6 +31,7 @@ > > #include <drm/drm_mode.h> > > #include <drm/drm_plane_helper.h> > > #include <drm/drm_print.h> > > +#include <drm/drm_writeback.h> > > #include <linux/sync_file.h> > > > > #include "drm_crtc_internal.h" > > @@ -654,6 +655,46 @@ static void drm_atomic_crtc_print_state(struct drm_printer *p, > > } > > > > /** > > + * drm_atomic_connector_check - check connector state > > + * @connector: connector to check > > + * @state: connector state to check > > + * > > + * Provides core sanity checks for connector state. > > + * > > + * RETURNS: > > + * Zero on success, error code on failure > > + */ > > +static int drm_atomic_connector_check(struct drm_connector *connector, > > + struct drm_connector_state *state) > > +{ > > + struct drm_crtc_state *crtc_state; > > + struct drm_writeback_job *writeback_job = state->writeback_job; > > + > > + if ((connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK) || > > + !writeback_job) > > + return 0; > > + > > + if (writeback_job->fb && !state->crtc) { > > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] framebuffer without CRTC\n", > > + connector->base.id, connector->name); > > + return -EINVAL; > > + } > > + > > + if (state->crtc) > > + crtc_state = drm_atomic_get_existing_crtc_state(state->state, > > + state->crtc); > > + > > + if (writeback_job->fb && !crtc_state->active) { > > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] has framebuffer, but [CRTC:%d] is off\n", > > + connector->base.id, connector->name, > > + state->crtc->base.id); > > + return -EINVAL; > > + } > > + > > + return 0; > > +} > > + > > +/** > > * drm_atomic_get_plane_state - get plane state > > * @state: global atomic state object > > * @plane: plane to get state object for > > @@ -1123,6 +1164,12 @@ int drm_atomic_connector_set_property(struct drm_connector *connector, > > */ > > if (state->link_status != DRM_LINK_STATUS_GOOD) > > state->link_status = val; > > + } else if (property == config->writeback_fb_id_property) { > > + struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, val); > > + int ret = drm_atomic_set_writeback_fb_for_connector(state, fb); > > + if (fb) > > + drm_framebuffer_unreference(fb); > > + return ret; > > } else if (connector->funcs->atomic_set_property) { > > return connector->funcs->atomic_set_property(connector, > > state, property, val); > > @@ -1199,6 +1246,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector, > > *val = state->tv.hue; > > } else if (property == config->link_status_property) { > > *val = state->link_status; > > + } else if (property == config->writeback_fb_id_property) { > > + /* Writeback framebuffer is one-shot, write and forget */ > > + *val = 0; > > } else if (connector->funcs->atomic_get_property) { > > return connector->funcs->atomic_get_property(connector, > > state, property, val); > > @@ -1406,6 +1456,75 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, > > } > > EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector); > > > > +/* > > + * drm_atomic_get_writeback_job - return or allocate a writeback job > > + * @conn_state: Connector state to get the job for > > + * > > + * Writeback jobs have a different lifetime to the atomic state they are > > + * associated with. This convenience function takes care of allocating a job > > + * if there isn't yet one associated with the connector state, otherwise > > + * it just returns the existing job. > > + * > > + * Returns: The writeback job for the given connector state > > + */ > > +static struct drm_writeback_job * > > +drm_atomic_get_writeback_job(struct drm_connector_state *conn_state) > > +{ > > + WARN_ON(conn_state->connector->connector_type != > > + DRM_MODE_CONNECTOR_WRITEBACK); > > + > > + if (!conn_state->writeback_job) > > + conn_state->writeback_job = > > + kzalloc(sizeof(*conn_state->writeback_job), GFP_KERNEL); > > + > > + return conn_state->writeback_job; > > +} > > + > > +/** > > + * drm_atomic_set_writeback_fb_for_connector - set writeback framebuffer > > + * @conn_state: atomic state object for the connector > > + * @fb: fb to use for the connector > > + * > > + * This is used to set the framebuffer for a writeback connector, which outputs > > + * to a buffer instead of an actual physical connector. > > + * Changing the assigned framebuffer requires us to grab a reference to the new > > + * fb and drop the reference to the old fb, if there is one. This function > > + * takes care of all these details besides updating the pointer in the > > + * state object itself. > > + * > > + * Note: The only way conn_state can already have an fb set is if the commit > > + * sets the property more than once. > > + * > > + * See also: drm_writeback_connector_init() > > + * > > + * Returns: 0 on success > > + */ > > +int drm_atomic_set_writeback_fb_for_connector( > > + struct drm_connector_state *conn_state, > > + struct drm_framebuffer *fb) > > +{ > > + struct drm_writeback_job *job = > > + drm_atomic_get_writeback_job(conn_state); > > + if (!job) > > + return -ENOMEM; > > + > > + if (job->fb) > > + drm_framebuffer_unreference(job->fb); > > + if (fb) > > + drm_framebuffer_reference(fb); > > + job->fb = fb; > > + > > + if (fb) > > + DRM_DEBUG_ATOMIC("Set [FB:%d] for connector state %p\n", > > + fb->base.id, conn_state); > > + else > > + DRM_DEBUG_ATOMIC("Set [NOFB] for connector state %p\n", > > + conn_state); > > + > > + return 0; > > +} > > +EXPORT_SYMBOL(drm_atomic_set_writeback_fb_for_connector); > > + > > /** > > * drm_atomic_add_affected_connectors - add connectors for crtc > > * @state: atomic state > > @@ -1556,6 +1675,8 @@ int drm_atomic_check_only(struct drm_atomic_state *state) > > struct drm_plane_state *plane_state; > > struct drm_crtc *crtc; > > struct drm_crtc_state *crtc_state; > > + struct drm_connector *conn; > > + struct drm_connector_state *conn_state; > > int i, ret = 0; > > > > DRM_DEBUG_ATOMIC("checking %p\n", state); > > @@ -1578,6 +1699,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state) > > } > > } > > > > + for_each_connector_in_state(state, conn, conn_state, i) { > > + ret = drm_atomic_connector_check(conn, conn_state); > > + if (ret) { > > + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] atomic core check failed\n", > > + conn->base.id, conn->name); > > + return ret; > > + } > > + } > > + > > if (config->funcs->atomic_check) > > ret = config->funcs->atomic_check(state->dev, state); > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 8be9719284b0..fa2d8d7a602a 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -30,6 +30,7 @@ > > #include <drm/drm_plane_helper.h> > > #include <drm/drm_crtc_helper.h> > > #include <drm/drm_atomic_helper.h> > > +#include <drm/drm_writeback.h> > > #include <linux/dma-fence.h> > > > > #include "drm_crtc_internal.h" > > @@ -3361,6 +3362,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector, > > memcpy(state, connector->state, sizeof(*state)); > > if (state->crtc) > > drm_connector_get(connector); > > + > > + /* Don't copy over a writeback job, they are used only once */ > > + state->writeback_job = NULL; > > } > > EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state); > > > > @@ -3487,6 +3491,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state) > > { > > if (state->crtc) > > drm_connector_put(state->connector); > > + if (state->writeback_job) > > + drm_writeback_cleanup_job(state->writeback_job); > > } > > EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state); > > > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > > index 9f847615ac74..fb9ace3ef744 100644 > > --- a/drivers/gpu/drm/drm_connector.c > > +++ b/drivers/gpu/drm/drm_connector.c > > @@ -86,6 +86,7 @@ static struct drm_conn_prop_enum_list drm_connector_enum_list[] = { > > { DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" }, > > { DRM_MODE_CONNECTOR_DSI, "DSI" }, > > { DRM_MODE_CONNECTOR_DPI, "DPI" }, > > + { DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" }, > > }; > > > > void drm_connector_ida_init(void) > > @@ -222,7 +223,8 @@ int drm_connector_init(struct drm_device *dev, > > config->num_connector++; > > spin_unlock_irq(&config->connector_list_lock); > > > > - if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL) > > + if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL && > > + connector_type != DRM_MODE_CONNECTOR_WRITEBACK) > > drm_object_attach_property(&connector->base, > > config->edid_property, > > 0); > > diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c > > new file mode 100644 > > index 000000000000..48c8599e8248 > > --- /dev/null > > +++ b/drivers/gpu/drm/drm_writeback.c > > @@ -0,0 +1,257 @@ > > +/* > > + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. > > + * Author: Brian Starkey <brian.starkey@arm.com> > > + * > > + * This program is free software and is provided to you under the terms of the > > + * GNU General Public License version 2 as published by the Free Software > > + * Foundation, and any use by you of this program is subject to the terms > > + * of such GNU licence. > > + */ > > + > > +#include <drm/drm_crtc.h> > > +#include <drm/drm_modeset_helper_vtables.h> > > +#include <drm/drm_property.h> > > +#include <drm/drm_writeback.h> > > +#include <drm/drmP.h> > > + > > +/** > > + * DOC: overview > > + * > > + * Writeback connectors are used to expose hardware which can write the output > > + * from a CRTC to a memory buffer. They are used and act similarly to other > > + * types of connectors, with some important differences: > > + * - Writeback connectors don't provide a way to output visually to the user. > > + * - Writeback connectors should always report as "disconnected" (so that > > + * clients which don't understand them will ignore them). > > + * - Writeback connectors don't have EDID. > > + * > > + * A framebuffer may only be attached to a writeback connector when the > > + * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the > > + * framebuffer applies only to a single commit (see below). A framebuffer may > > + * not be attached while the CRTC is off. > > + * > > + * Writeback connectors have some additional properties, which userspace > > + * can use to query and control them: > > + * > > + * "WRITEBACK_FB_ID": > > + * Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the > > + * framebuffer to be written by the writeback connector. This property is > > + * similar to the FB_ID property on planes, but will always read as zero > > + * and is not preserved across commits. > > + * Userspace must set this property to an output buffer every time it > > + * wishes the buffer to get filled. > > + * > > + * "WRITEBACK_PIXEL_FORMATS": > > + * Immutable blob property to store the supported pixel formats table. The > > + * 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. > > + */ > > + > > +static bool create_writeback_properties(struct drm_device *dev) > > +{ > > + struct drm_property *prop; > > + > > + if (!dev->mode_config.writeback_fb_id_property) { > > + prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, > > + "WRITEBACK_FB_ID", > > + DRM_MODE_OBJECT_FB); > > + if (!prop) > > + return false; > > + dev->mode_config.writeback_fb_id_property = prop; > > + } > > + > > + if (!dev->mode_config.writeback_pixel_formats_property) { > > + prop = drm_property_create(dev, DRM_MODE_PROP_BLOB | DRM_MODE_PROP_IMMUTABLE, > > + "WRITEBACK_PIXEL_FORMATS", 0); > > + if (!prop) > > + return false; > > + dev->mode_config.writeback_pixel_formats_property = prop; > > + } > > + > > + return true; > > +} > > + > > +static const struct drm_encoder_funcs drm_writeback_encoder_funcs = { > > + .destroy = drm_encoder_cleanup, > > +}; > > + > > +/** > > + * drm_writeback_connector_init - Initialize a writeback connector and its properties > > + * @dev: DRM device > > + * @wb_connector: Writeback connector to initialize > > + * @con_funcs: Connector funcs vtable > > + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder > > + * @formats: Array of supported pixel formats for the writeback engine > > + * @n_formats: Length of the formats array > > + * > > + * This function creates the writeback-connector-specific properties if they > > + * have not been already created, initializes the connector as > > + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property > > + * values. It will also create an internal encoder associated with the > > + * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for > > + * the encoder helper. > > + * > > + * Drivers should always use this function instead of drm_connector_init() to > > + * set up writeback connectors. > > + * > > + * Returns: 0 on success, or a negative error code > > + */ > > +int drm_writeback_connector_init(struct drm_device *dev, > > + struct drm_writeback_connector *wb_connector, > > + const struct drm_connector_funcs *con_funcs, > > + const struct drm_encoder_helper_funcs *enc_helper_funcs, > > + const u32 *formats, int n_formats) > > +{ > > + int ret; > > + struct drm_property_blob *blob; > > + struct drm_connector *connector = &wb_connector->base; > > + struct drm_mode_config *config = &dev->mode_config; > > + > > + if (!create_writeback_properties(dev)) > > + return -EINVAL; > > + > > + blob = drm_property_create_blob(dev, n_formats * sizeof(*formats), > > + formats); > > + if (IS_ERR(blob)) > > + return PTR_ERR(blob); > > + > > + drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs); > > + ret = drm_encoder_init(dev, &wb_connector->encoder, > > + &drm_writeback_encoder_funcs, > > + DRM_MODE_ENCODER_VIRTUAL, NULL); > > + if (ret) > > + goto fail; > > + > > + connector->interlace_allowed = 0; > > + > > + ret = drm_connector_init(dev, connector, con_funcs, > > + DRM_MODE_CONNECTOR_WRITEBACK); > > + if (ret) > > + goto connector_fail; > > + > > + ret = drm_mode_connector_attach_encoder(connector, > > + &wb_connector->encoder); > > + if (ret) > > + goto attach_fail; > > + > > + INIT_LIST_HEAD(&wb_connector->job_queue); > > + spin_lock_init(&wb_connector->job_lock); > > + > > + drm_object_attach_property(&connector->base, > > + config->writeback_fb_id_property, 0); > > + > > + drm_object_attach_property(&connector->base, > > + config->writeback_pixel_formats_property, > > + blob->base.id); > > + wb_connector->pixel_formats_blob_ptr = blob; > > + > > + return 0; > > + > > +attach_fail: > > + drm_connector_cleanup(connector); > > +connector_fail: > > + drm_encoder_cleanup(&wb_connector->encoder); > > +fail: > > + drm_property_unreference_blob(blob); > > + return ret; > > +} > > +EXPORT_SYMBOL(drm_writeback_connector_init); > > + > > +/** > > + * @drm_writeback_queue_job: Queue a writeback job for later signalling > > + * @wb_connector: The writeback connector to queue a job on > > + * @job: The job to queue > > + * > > + * This function adds a job to the job_queue for a writeback connector. It > > + * should be considered to take ownership of the writeback job, and so any other > > + * references to the job must be cleared after calling this function. > > + * > > + * Drivers must ensure that for a given writeback connector, jobs are queued in > > + * exactly the same order as they will be completed by the hardware (and > > + * signaled via drm_writeback_signal_completion). > > + * > > + * For every call to drm_writeback_queue_job() there must be exactly one call to > > + * drm_writeback_signal_completion() > > + * > > + * See also: drm_writeback_signal_completion() > > + */ > > +void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector, > > + struct drm_writeback_job *job) > > +{ > > + unsigned long flags; > > + > > + spin_lock_irqsave(&wb_connector->job_lock, flags); > > + list_add_tail(&job->list_entry, &wb_connector->job_queue); > > + spin_unlock_irqrestore(&wb_connector->job_lock, flags); > > +} > > +EXPORT_SYMBOL(drm_writeback_queue_job); > > + > > +/** > > + * @drm_writeback_cleanup_job: Cleanup and free a writeback job > > + * @job: The writeback job to free > > + * > > + * Drops any references held by the writeback job, and frees the structure. > > + */ > > +void drm_writeback_cleanup_job(struct drm_writeback_job *job) > > +{ > > + if (!job) > > + return; > > + > > + if (job->fb) > > + drm_framebuffer_unreference(job->fb); > > + kfree(job); > > +} > > +EXPORT_SYMBOL(drm_writeback_cleanup_job); > > + > > +/* > > + * @cleanup_work: deferred cleanup of a writeback job > > + * > > + * The job cannot be cleaned up directly in drm_writeback_signal_completion, > > + * because it may be called in interrupt context. Dropping the framebuffer > > + * reference can sleep, and so the cleanup is deferred to a workqueue. > > + */ > > +static void cleanup_work(struct work_struct *work) > > +{ > > + struct drm_writeback_job *job = container_of(work, > > + struct drm_writeback_job, > > + cleanup_work); > > + drm_writeback_cleanup_job(job); > > +} > > + > > +/** > > + * @drm_writeback_signal_completion: Signal the completion of a writeback job > > + * @wb_connector: The writeback connector whose job is complete > > + * > > + * 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 > > + * has finished writing, and may be called from interrupt context. > > + * It is the driver's responsibility to ensure that for a given connector, the > > + * hardware completes writeback jobs in the same order as they are queued. > > + * > > + * Unless the driver is holding its own reference to the framebuffer, it must > > + * not be accessed after calling this function. > > + * > > + * See also: drm_writeback_queue_job() > > + */ > > +void > > +drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) > > +{ > > + unsigned long flags; > > + struct drm_writeback_job *job; > > + > > + spin_lock_irqsave(&wb_connector->job_lock, flags); > > + job = list_first_entry_or_null(&wb_connector->job_queue, > > + struct drm_writeback_job, > > + list_entry); > > + if (job) > > + list_del(&job->list_entry); > > + spin_unlock_irqrestore(&wb_connector->job_lock, flags); > > + > > + if (WARN_ON(!job)) > > + return; > > + > > + INIT_WORK(&job->cleanup_work, cleanup_work); > > + queue_work(system_long_wq, &job->cleanup_work); > > +} > > +EXPORT_SYMBOL(drm_writeback_signal_completion); > > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h > > index 788daf756f48..183b7c60adab 100644 > > --- a/include/drm/drm_atomic.h > > +++ b/include/drm/drm_atomic.h > > @@ -478,6 +478,9 @@ void drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state, > > int __must_check > > drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, > > struct drm_crtc *crtc); > > +int drm_atomic_set_writeback_fb_for_connector( > > + struct drm_connector_state *conn_state, > > + struct drm_framebuffer *fb); > > int __must_check > > drm_atomic_add_affected_connectors(struct drm_atomic_state *state, > > struct drm_crtc *crtc); > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > > index 4eeda120e46d..c97a4729c071 100644 > > --- a/include/drm/drm_connector.h > > +++ b/include/drm/drm_connector.h > > @@ -326,6 +326,19 @@ struct drm_connector_state { > > struct drm_atomic_state *state; > > > > struct drm_tv_connector_state tv; > > + > > + /** > > + * @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. > > + * > > + * See also: drm_writeback_queue_job() and > > + * drm_writeback_signal_completion() > > + */ > > + struct drm_writeback_job *writeback_job; > > }; > > > > /** > > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > > index 42981711189b..cbc1b2998085 100644 > > --- a/include/drm/drm_mode_config.h > > +++ b/include/drm/drm_mode_config.h > > @@ -741,6 +741,20 @@ struct drm_mode_config { > > */ > > struct drm_property *suggested_y_property; > > > > + /** > > + * @writeback_fb_id_property: Property for writeback connectors, storing > > + * the ID of the output framebuffer. > > + * See also: drm_writeback_connector_init() > > + */ > > + struct drm_property *writeback_fb_id_property; > > + /** > > + * @writeback_pixel_formats_property: Property for writeback connectors, > > + * storing an array of the supported pixel formats for the writeback > > + * engine (read-only). > > + * See also: drm_writeback_connector_init() > > + */ > > + struct drm_property *writeback_pixel_formats_property; > > + > > /* dumb ioctl parameters */ > > uint32_t preferred_depth, prefer_shadow; > > > > diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h > > new file mode 100644 > > index 000000000000..cf3a28676006 > > --- /dev/null > > +++ b/include/drm/drm_writeback.h > > @@ -0,0 +1,88 @@ > > +/* > > + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. > > + * Author: Brian Starkey <brian.starkey@arm.com> > > + * > > + * This program is free software and is provided to you under the terms of the > > + * GNU General Public License version 2 as published by the Free Software > > + * Foundation, and any use by you of this program is subject to the terms > > + * of such GNU licence. > > + */ > > + > > +#ifndef __DRM_WRITEBACK_H__ > > +#define __DRM_WRITEBACK_H__ > > +#include <drm/drm_connector.h> > > +#include <drm/drm_encoder.h> > > +#include <linux/workqueue.h> > > + > > +struct drm_writeback_connector { > > + struct drm_connector base; > > + > > + /** > > + * @encoder: Internal encoder used by the connector to fulfill > > + * the DRM framework requirements. The users of the > > + * @drm_writeback_connector control the behaviour of the @encoder > > + * by passing the @enc_funcs parameter to drm_writeback_connector_init() > > + * function. > > + */ > > + struct drm_encoder encoder; > > + > > + /** > > + * @pixel_formats_blob_ptr: > > + * > > + * DRM blob property data for the pixel formats list on writeback > > + * connectors > > + * See also drm_writeback_connector_init() > > + */ > > + struct drm_property_blob *pixel_formats_blob_ptr; > > + > > + /** @job_lock: Protects job_queue */ > > + spinlock_t job_lock; > > + > > + /** > > + * @job_queue: > > + * > > + * Holds a list of a connector's writeback jobs; the last item is the > > + * most recent. The first item may be either waiting for the hardware > > + * to begin writing, or currently being written. > > + * > > + * See also: drm_writeback_queue_job() and > > + * drm_writeback_signal_completion() > > + */ > > + struct list_head job_queue; > > +}; > > + > > +struct drm_writeback_job { > > + /** > > + * @cleanup_work: > > + * > > + * Used to allow drm_writeback_signal_completion to defer dropping the > > + * framebuffer reference to a workqueue. > > + */ > > + struct work_struct cleanup_work; > > + /** > > + * @list_entry: > > + * > > + * List item for the connector's @job_queue > > + */ > > + struct list_head list_entry; > > + /** > > + * @fb: > > + * > > + * Framebuffer to be written to by the writeback connector. Do not set > > + * directly, use drm_atomic_set_writeback_fb_for_connector() > > + */ > > + struct drm_framebuffer *fb; > > +}; > > + > > +int drm_writeback_connector_init(struct drm_device *dev, > > + struct drm_writeback_connector *wb_connector, > > + const struct drm_connector_funcs *con_funcs, > > + const struct drm_encoder_helper_funcs *enc_helper_funcs, > > + const u32 *formats, int n_formats); > > + > > +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); > > +#endif > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > > index 8c67fc03d53d..686ae5599c22 100644 > > --- a/include/uapi/drm/drm_mode.h > > +++ b/include/uapi/drm/drm_mode.h > > @@ -269,6 +269,7 @@ enum drm_mode_subconnector { > > #define DRM_MODE_CONNECTOR_VIRTUAL 15 > > #define DRM_MODE_CONNECTOR_DSI 16 > > #define DRM_MODE_CONNECTOR_DPI 17 > > +#define DRM_MODE_CONNECTOR_WRITEBACK 18 > > > > struct drm_mode_get_connector { > > > > -- > > 2.12.2 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst index bfecd21a8cdf..7a8ef1a4fe17 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -364,6 +364,15 @@ Connector Functions Reference .. kernel-doc:: drivers/gpu/drm/drm_connector.c :export: +Writeback Connectors +-------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c + :doc: overview + +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c + :export: + Encoder Abstraction =================== diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 59f0f9b696eb..99ef500ae8b2 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -16,7 +16,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \ drm_framebuffer.o drm_connector.o drm_blend.o \ drm_encoder.o drm_mode_object.o drm_property.o \ drm_plane.o drm_color_mgmt.o drm_print.o \ - drm_dumb_buffers.o drm_mode_config.o + drm_dumb_buffers.o drm_mode_config.o drm_writeback.o drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o drm-$(CONFIG_DRM_VM) += drm_vm.o diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index f32506a7c1d6..317ae625b417 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -31,6 +31,7 @@ #include <drm/drm_mode.h> #include <drm/drm_plane_helper.h> #include <drm/drm_print.h> +#include <drm/drm_writeback.h> #include <linux/sync_file.h> #include "drm_crtc_internal.h" @@ -654,6 +655,46 @@ static void drm_atomic_crtc_print_state(struct drm_printer *p, } /** + * drm_atomic_connector_check - check connector state + * @connector: connector to check + * @state: connector state to check + * + * Provides core sanity checks for connector state. + * + * RETURNS: + * Zero on success, error code on failure + */ +static int drm_atomic_connector_check(struct drm_connector *connector, + struct drm_connector_state *state) +{ + struct drm_crtc_state *crtc_state; + struct drm_writeback_job *writeback_job = state->writeback_job; + + if ((connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK) || + !writeback_job) + return 0; + + if (writeback_job->fb && !state->crtc) { + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] framebuffer without CRTC\n", + connector->base.id, connector->name); + return -EINVAL; + } + + if (state->crtc) + crtc_state = drm_atomic_get_existing_crtc_state(state->state, + state->crtc); + + if (writeback_job->fb && !crtc_state->active) { + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] has framebuffer, but [CRTC:%d] is off\n", + connector->base.id, connector->name, + state->crtc->base.id); + return -EINVAL; + } + + return 0; +} + +/** * drm_atomic_get_plane_state - get plane state * @state: global atomic state object * @plane: plane to get state object for @@ -1123,6 +1164,12 @@ int drm_atomic_connector_set_property(struct drm_connector *connector, */ if (state->link_status != DRM_LINK_STATUS_GOOD) state->link_status = val; + } else if (property == config->writeback_fb_id_property) { + struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, val); + int ret = drm_atomic_set_writeback_fb_for_connector(state, fb); + if (fb) + drm_framebuffer_unreference(fb); + return ret; } else if (connector->funcs->atomic_set_property) { return connector->funcs->atomic_set_property(connector, state, property, val); @@ -1199,6 +1246,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector, *val = state->tv.hue; } else if (property == config->link_status_property) { *val = state->link_status; + } else if (property == config->writeback_fb_id_property) { + /* Writeback framebuffer is one-shot, write and forget */ + *val = 0; } else if (connector->funcs->atomic_get_property) { return connector->funcs->atomic_get_property(connector, state, property, val); @@ -1406,6 +1456,75 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, } EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector); +/* + * drm_atomic_get_writeback_job - return or allocate a writeback job + * @conn_state: Connector state to get the job for + * + * Writeback jobs have a different lifetime to the atomic state they are + * associated with. This convenience function takes care of allocating a job + * if there isn't yet one associated with the connector state, otherwise + * it just returns the existing job. + * + * Returns: The writeback job for the given connector state + */ +static struct drm_writeback_job * +drm_atomic_get_writeback_job(struct drm_connector_state *conn_state) +{ + WARN_ON(conn_state->connector->connector_type != + DRM_MODE_CONNECTOR_WRITEBACK); + + if (!conn_state->writeback_job) + conn_state->writeback_job = + kzalloc(sizeof(*conn_state->writeback_job), GFP_KERNEL); + + return conn_state->writeback_job; +} + +/** + * drm_atomic_set_writeback_fb_for_connector - set writeback framebuffer + * @conn_state: atomic state object for the connector + * @fb: fb to use for the connector + * + * This is used to set the framebuffer for a writeback connector, which outputs + * to a buffer instead of an actual physical connector. + * Changing the assigned framebuffer requires us to grab a reference to the new + * fb and drop the reference to the old fb, if there is one. This function + * takes care of all these details besides updating the pointer in the + * state object itself. + * + * Note: The only way conn_state can already have an fb set is if the commit + * sets the property more than once. + * + * See also: drm_writeback_connector_init() + * + * Returns: 0 on success + */ +int drm_atomic_set_writeback_fb_for_connector( + struct drm_connector_state *conn_state, + struct drm_framebuffer *fb) +{ + struct drm_writeback_job *job = + drm_atomic_get_writeback_job(conn_state); + if (!job) + return -ENOMEM; + + if (job->fb) + drm_framebuffer_unreference(job->fb); + if (fb) + drm_framebuffer_reference(fb); + job->fb = fb; + + if (fb) + DRM_DEBUG_ATOMIC("Set [FB:%d] for connector state %p\n", + fb->base.id, conn_state); + else + DRM_DEBUG_ATOMIC("Set [NOFB] for connector state %p\n", + conn_state); + + return 0; +} +EXPORT_SYMBOL(drm_atomic_set_writeback_fb_for_connector); + /** * drm_atomic_add_affected_connectors - add connectors for crtc * @state: atomic state @@ -1556,6 +1675,8 @@ int drm_atomic_check_only(struct drm_atomic_state *state) struct drm_plane_state *plane_state; struct drm_crtc *crtc; struct drm_crtc_state *crtc_state; + struct drm_connector *conn; + struct drm_connector_state *conn_state; int i, ret = 0; DRM_DEBUG_ATOMIC("checking %p\n", state); @@ -1578,6 +1699,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state) } } + for_each_connector_in_state(state, conn, conn_state, i) { + ret = drm_atomic_connector_check(conn, conn_state); + if (ret) { + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] atomic core check failed\n", + conn->base.id, conn->name); + return ret; + } + } + if (config->funcs->atomic_check) ret = config->funcs->atomic_check(state->dev, state); diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 8be9719284b0..fa2d8d7a602a 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -30,6 +30,7 @@ #include <drm/drm_plane_helper.h> #include <drm/drm_crtc_helper.h> #include <drm/drm_atomic_helper.h> +#include <drm/drm_writeback.h> #include <linux/dma-fence.h> #include "drm_crtc_internal.h" @@ -3361,6 +3362,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector, memcpy(state, connector->state, sizeof(*state)); if (state->crtc) drm_connector_get(connector); + + /* Don't copy over a writeback job, they are used only once */ + state->writeback_job = NULL; } EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state); @@ -3487,6 +3491,8 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state) { if (state->crtc) drm_connector_put(state->connector); + if (state->writeback_job) + drm_writeback_cleanup_job(state->writeback_job); } EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state); diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 9f847615ac74..fb9ace3ef744 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -86,6 +86,7 @@ static struct drm_conn_prop_enum_list drm_connector_enum_list[] = { { DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" }, { DRM_MODE_CONNECTOR_DSI, "DSI" }, { DRM_MODE_CONNECTOR_DPI, "DPI" }, + { DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" }, }; void drm_connector_ida_init(void) @@ -222,7 +223,8 @@ int drm_connector_init(struct drm_device *dev, config->num_connector++; spin_unlock_irq(&config->connector_list_lock); - if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL) + if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL && + connector_type != DRM_MODE_CONNECTOR_WRITEBACK) drm_object_attach_property(&connector->base, config->edid_property, 0); diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c new file mode 100644 index 000000000000..48c8599e8248 --- /dev/null +++ b/drivers/gpu/drm/drm_writeback.c @@ -0,0 +1,257 @@ +/* + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. + * Author: Brian Starkey <brian.starkey@arm.com> + * + * This program is free software and is provided to you under the terms of the + * GNU General Public License version 2 as published by the Free Software + * Foundation, and any use by you of this program is subject to the terms + * of such GNU licence. + */ + +#include <drm/drm_crtc.h> +#include <drm/drm_modeset_helper_vtables.h> +#include <drm/drm_property.h> +#include <drm/drm_writeback.h> +#include <drm/drmP.h> + +/** + * DOC: overview + * + * Writeback connectors are used to expose hardware which can write the output + * from a CRTC to a memory buffer. They are used and act similarly to other + * types of connectors, with some important differences: + * - Writeback connectors don't provide a way to output visually to the user. + * - Writeback connectors should always report as "disconnected" (so that + * clients which don't understand them will ignore them). + * - Writeback connectors don't have EDID. + * + * A framebuffer may only be attached to a writeback connector when the + * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the + * framebuffer applies only to a single commit (see below). A framebuffer may + * not be attached while the CRTC is off. + * + * Writeback connectors have some additional properties, which userspace + * can use to query and control them: + * + * "WRITEBACK_FB_ID": + * Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the + * framebuffer to be written by the writeback connector. This property is + * similar to the FB_ID property on planes, but will always read as zero + * and is not preserved across commits. + * Userspace must set this property to an output buffer every time it + * wishes the buffer to get filled. + * + * "WRITEBACK_PIXEL_FORMATS": + * Immutable blob property to store the supported pixel formats table. The + * 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. + */ + +static bool create_writeback_properties(struct drm_device *dev) +{ + struct drm_property *prop; + + if (!dev->mode_config.writeback_fb_id_property) { + prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC, + "WRITEBACK_FB_ID", + DRM_MODE_OBJECT_FB); + if (!prop) + return false; + dev->mode_config.writeback_fb_id_property = prop; + } + + if (!dev->mode_config.writeback_pixel_formats_property) { + prop = drm_property_create(dev, DRM_MODE_PROP_BLOB | DRM_MODE_PROP_IMMUTABLE, + "WRITEBACK_PIXEL_FORMATS", 0); + if (!prop) + return false; + dev->mode_config.writeback_pixel_formats_property = prop; + } + + return true; +} + +static const struct drm_encoder_funcs drm_writeback_encoder_funcs = { + .destroy = drm_encoder_cleanup, +}; + +/** + * drm_writeback_connector_init - Initialize a writeback connector and its properties + * @dev: DRM device + * @wb_connector: Writeback connector to initialize + * @con_funcs: Connector funcs vtable + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder + * @formats: Array of supported pixel formats for the writeback engine + * @n_formats: Length of the formats array + * + * This function creates the writeback-connector-specific properties if they + * have not been already created, initializes the connector as + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property + * values. It will also create an internal encoder associated with the + * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for + * the encoder helper. + * + * Drivers should always use this function instead of drm_connector_init() to + * set up writeback connectors. + * + * Returns: 0 on success, or a negative error code + */ +int drm_writeback_connector_init(struct drm_device *dev, + struct drm_writeback_connector *wb_connector, + const struct drm_connector_funcs *con_funcs, + const struct drm_encoder_helper_funcs *enc_helper_funcs, + const u32 *formats, int n_formats) +{ + int ret; + struct drm_property_blob *blob; + struct drm_connector *connector = &wb_connector->base; + struct drm_mode_config *config = &dev->mode_config; + + if (!create_writeback_properties(dev)) + return -EINVAL; + + blob = drm_property_create_blob(dev, n_formats * sizeof(*formats), + formats); + if (IS_ERR(blob)) + return PTR_ERR(blob); + + drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs); + ret = drm_encoder_init(dev, &wb_connector->encoder, + &drm_writeback_encoder_funcs, + DRM_MODE_ENCODER_VIRTUAL, NULL); + if (ret) + goto fail; + + connector->interlace_allowed = 0; + + ret = drm_connector_init(dev, connector, con_funcs, + DRM_MODE_CONNECTOR_WRITEBACK); + if (ret) + goto connector_fail; + + ret = drm_mode_connector_attach_encoder(connector, + &wb_connector->encoder); + if (ret) + goto attach_fail; + + INIT_LIST_HEAD(&wb_connector->job_queue); + spin_lock_init(&wb_connector->job_lock); + + drm_object_attach_property(&connector->base, + config->writeback_fb_id_property, 0); + + drm_object_attach_property(&connector->base, + config->writeback_pixel_formats_property, + blob->base.id); + wb_connector->pixel_formats_blob_ptr = blob; + + return 0; + +attach_fail: + drm_connector_cleanup(connector); +connector_fail: + drm_encoder_cleanup(&wb_connector->encoder); +fail: + drm_property_unreference_blob(blob); + return ret; +} +EXPORT_SYMBOL(drm_writeback_connector_init); + +/** + * @drm_writeback_queue_job: Queue a writeback job for later signalling + * @wb_connector: The writeback connector to queue a job on + * @job: The job to queue + * + * This function adds a job to the job_queue for a writeback connector. It + * should be considered to take ownership of the writeback job, and so any other + * references to the job must be cleared after calling this function. + * + * Drivers must ensure that for a given writeback connector, jobs are queued in + * exactly the same order as they will be completed by the hardware (and + * signaled via drm_writeback_signal_completion). + * + * For every call to drm_writeback_queue_job() there must be exactly one call to + * drm_writeback_signal_completion() + * + * See also: drm_writeback_signal_completion() + */ +void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector, + struct drm_writeback_job *job) +{ + unsigned long flags; + + spin_lock_irqsave(&wb_connector->job_lock, flags); + list_add_tail(&job->list_entry, &wb_connector->job_queue); + spin_unlock_irqrestore(&wb_connector->job_lock, flags); +} +EXPORT_SYMBOL(drm_writeback_queue_job); + +/** + * @drm_writeback_cleanup_job: Cleanup and free a writeback job + * @job: The writeback job to free + * + * Drops any references held by the writeback job, and frees the structure. + */ +void drm_writeback_cleanup_job(struct drm_writeback_job *job) +{ + if (!job) + return; + + if (job->fb) + drm_framebuffer_unreference(job->fb); + kfree(job); +} +EXPORT_SYMBOL(drm_writeback_cleanup_job); + +/* + * @cleanup_work: deferred cleanup of a writeback job + * + * The job cannot be cleaned up directly in drm_writeback_signal_completion, + * because it may be called in interrupt context. Dropping the framebuffer + * reference can sleep, and so the cleanup is deferred to a workqueue. + */ +static void cleanup_work(struct work_struct *work) +{ + struct drm_writeback_job *job = container_of(work, + struct drm_writeback_job, + cleanup_work); + drm_writeback_cleanup_job(job); +} + +/** + * @drm_writeback_signal_completion: Signal the completion of a writeback job + * @wb_connector: The writeback connector whose job is complete + * + * 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 + * has finished writing, and may be called from interrupt context. + * It is the driver's responsibility to ensure that for a given connector, the + * hardware completes writeback jobs in the same order as they are queued. + * + * Unless the driver is holding its own reference to the framebuffer, it must + * not be accessed after calling this function. + * + * See also: drm_writeback_queue_job() + */ +void +drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector) +{ + unsigned long flags; + struct drm_writeback_job *job; + + spin_lock_irqsave(&wb_connector->job_lock, flags); + job = list_first_entry_or_null(&wb_connector->job_queue, + struct drm_writeback_job, + list_entry); + if (job) + list_del(&job->list_entry); + spin_unlock_irqrestore(&wb_connector->job_lock, flags); + + if (WARN_ON(!job)) + return; + + INIT_WORK(&job->cleanup_work, cleanup_work); + queue_work(system_long_wq, &job->cleanup_work); +} +EXPORT_SYMBOL(drm_writeback_signal_completion); diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h index 788daf756f48..183b7c60adab 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -478,6 +478,9 @@ void drm_atomic_set_fence_for_plane(struct drm_plane_state *plane_state, int __must_check drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state, struct drm_crtc *crtc); +int drm_atomic_set_writeback_fb_for_connector( + struct drm_connector_state *conn_state, + struct drm_framebuffer *fb); int __must_check drm_atomic_add_affected_connectors(struct drm_atomic_state *state, struct drm_crtc *crtc); diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 4eeda120e46d..c97a4729c071 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -326,6 +326,19 @@ struct drm_connector_state { struct drm_atomic_state *state; struct drm_tv_connector_state tv; + + /** + * @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. + * + * See also: drm_writeback_queue_job() and + * drm_writeback_signal_completion() + */ + struct drm_writeback_job *writeback_job; }; /** diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index 42981711189b..cbc1b2998085 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -741,6 +741,20 @@ struct drm_mode_config { */ struct drm_property *suggested_y_property; + /** + * @writeback_fb_id_property: Property for writeback connectors, storing + * the ID of the output framebuffer. + * See also: drm_writeback_connector_init() + */ + struct drm_property *writeback_fb_id_property; + /** + * @writeback_pixel_formats_property: Property for writeback connectors, + * storing an array of the supported pixel formats for the writeback + * engine (read-only). + * See also: drm_writeback_connector_init() + */ + struct drm_property *writeback_pixel_formats_property; + /* dumb ioctl parameters */ uint32_t preferred_depth, prefer_shadow; diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h new file mode 100644 index 000000000000..cf3a28676006 --- /dev/null +++ b/include/drm/drm_writeback.h @@ -0,0 +1,88 @@ +/* + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. + * Author: Brian Starkey <brian.starkey@arm.com> + * + * This program is free software and is provided to you under the terms of the + * GNU General Public License version 2 as published by the Free Software + * Foundation, and any use by you of this program is subject to the terms + * of such GNU licence. + */ + +#ifndef __DRM_WRITEBACK_H__ +#define __DRM_WRITEBACK_H__ +#include <drm/drm_connector.h> +#include <drm/drm_encoder.h> +#include <linux/workqueue.h> + +struct drm_writeback_connector { + struct drm_connector base; + + /** + * @encoder: Internal encoder used by the connector to fulfill + * the DRM framework requirements. The users of the + * @drm_writeback_connector control the behaviour of the @encoder + * by passing the @enc_funcs parameter to drm_writeback_connector_init() + * function. + */ + struct drm_encoder encoder; + + /** + * @pixel_formats_blob_ptr: + * + * DRM blob property data for the pixel formats list on writeback + * connectors + * See also drm_writeback_connector_init() + */ + struct drm_property_blob *pixel_formats_blob_ptr; + + /** @job_lock: Protects job_queue */ + spinlock_t job_lock; + + /** + * @job_queue: + * + * Holds a list of a connector's writeback jobs; the last item is the + * most recent. The first item may be either waiting for the hardware + * to begin writing, or currently being written. + * + * See also: drm_writeback_queue_job() and + * drm_writeback_signal_completion() + */ + struct list_head job_queue; +}; + +struct drm_writeback_job { + /** + * @cleanup_work: + * + * Used to allow drm_writeback_signal_completion to defer dropping the + * framebuffer reference to a workqueue. + */ + struct work_struct cleanup_work; + /** + * @list_entry: + * + * List item for the connector's @job_queue + */ + struct list_head list_entry; + /** + * @fb: + * + * Framebuffer to be written to by the writeback connector. Do not set + * directly, use drm_atomic_set_writeback_fb_for_connector() + */ + struct drm_framebuffer *fb; +}; + +int drm_writeback_connector_init(struct drm_device *dev, + struct drm_writeback_connector *wb_connector, + const struct drm_connector_funcs *con_funcs, + const struct drm_encoder_helper_funcs *enc_helper_funcs, + const u32 *formats, int n_formats); + +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); +#endif diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 8c67fc03d53d..686ae5599c22 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -269,6 +269,7 @@ enum drm_mode_subconnector { #define DRM_MODE_CONNECTOR_VIRTUAL 15 #define DRM_MODE_CONNECTOR_DSI 16 #define DRM_MODE_CONNECTOR_DPI 17 +#define DRM_MODE_CONNECTOR_WRITEBACK 18 struct drm_mode_get_connector {