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.

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 required from the drivers that are using it.

Changes since v5: - Added Rob Clark's atomic_commit() vfunc to connector helper funcs, so that writeback jobs are commited from atomic helpers - Updated create_writeback_properties() signature to return an error code rather than a boolean false for failure. - Free writeback job with the connector state rather than when doing the cleanup_work()

Signed-off-by: Brian Starkey brian.starkey@arm.com [rebased and fixed conflicts] Signed-off-by: Mihail Atanassov mihail.atanassov@arm.com [rebased and added atomic_commit() vfunc for writeback jobs] Signed-off-by: Rob Clark robdclark@gmail.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 | 128 ++++++++++++++++ drivers/gpu/drm/drm_atomic_helper.c | 30 ++++ drivers/gpu/drm/drm_connector.c | 4 +- drivers/gpu/drm/drm_writeback.c | 256 +++++++++++++++++++++++++++++++ include/drm/drm_atomic.h | 3 + include/drm/drm_connector.h | 13 ++ include/drm/drm_mode_config.h | 15 ++ include/drm/drm_modeset_helper_vtables.h | 11 ++ include/drm/drm_writeback.h | 88 +++++++++++ include/uapi/drm/drm_mode.h | 1 + 12 files changed, 558 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 56a3780e39b8..a0ee22020360 100644 --- a/Documentation/gpu/drm-kms.rst +++ b/Documentation/gpu/drm-kms.rst @@ -370,6 +370,15 @@ 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 50093ff4479b..3d708959b224 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -18,7 +18,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.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_vblank.o \ - drm_syncobj.o drm_lease.o + drm_syncobj.o drm_lease.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 46733d534587..b2a61aebe92c 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -30,6 +30,7 @@ #include <drm/drm_atomic.h> #include <drm/drm_mode.h> #include <drm/drm_print.h> +#include <drm/drm_writeback.h> #include <linux/sync_file.h>

#include "drm_crtc_internal.h" @@ -638,6 +639,45 @@ static void drm_atomic_crtc_print_state(struct drm_printer *p, crtc->funcs->atomic_print_state(p, state); }

+/** + * 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 @@ -1230,6 +1270,12 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector, return -EINVAL; } state->content_protection = val; + } else if (property == config->writeback_fb_id_property) { + struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, NULL, 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); @@ -1311,6 +1357,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector, *val = state->scaling_mode; } else if (property == connector->content_protection_property) { *val = state->content_protection; + } 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); @@ -1518,6 +1567,74 @@ 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 @@ -1636,6 +1753,8 @@ 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); @@ -1658,6 +1777,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state) } }

+ for_each_new_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 ae3cbfe9e01c..9c17a68d9799 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_helper_internal.h" @@ -1159,6 +1160,25 @@ void drm_atomic_helper_commit_modeset_disables(struct drm_device *dev, } EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_disables);

+static void drm_atomic_helper_commit_writebacks(struct drm_device *dev, + struct drm_atomic_state *old_state) +{ + struct drm_connector *connector; + struct drm_connector_state *new_conn_state; + int i; + + for_each_new_connector_in_state(old_state, connector, new_conn_state, i) { + const struct drm_connector_helper_funcs *funcs; + + funcs = connector->helper_private; + + if (new_conn_state->writeback_job && new_conn_state->writeback_job->fb) { + WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK); + funcs->atomic_commit(connector, new_conn_state->writeback_job); + } + } +} + /** * drm_atomic_helper_commit_modeset_enables - modeset commit to enable outputs * @dev: DRM device @@ -1238,6 +1258,8 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,

drm_bridge_enable(encoder->bridge); } + + drm_atomic_helper_commit_writebacks(dev, old_state); } EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);

@@ -3627,6 +3649,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector, if (state->crtc) drm_connector_get(connector); state->commit = NULL; + + /* Don't copy over a writeback job, they are used only once */ + state->writeback_job = NULL; } EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);

@@ -3756,6 +3781,11 @@ __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)

if (state->commit) drm_crtc_commit_put(state->commit); + + if (state->writeback_job) { + drm_writeback_cleanup_job(state->writeback_job); + kfree(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 b3cde897cd80..929c547ebb43 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -87,6 +87,7 @@ 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) @@ -249,7 +250,8 @@ 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..17cacd2170b0 --- /dev/null +++ b/drivers/gpu/drm/drm_writeback.c @@ -0,0 +1,256 @@ +/* + * (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 int 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 -ENOMEM; + 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_ATOMIC | + DRM_MODE_PROP_IMMUTABLE, + "WRITEBACK_PIXEL_FORMATS", 0); + if (!prop) + return -ENOMEM; + dev->mode_config.writeback_pixel_formats_property = prop; + } + + return 0; +} + +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) +{ + struct drm_property_blob *blob; + struct drm_connector *connector = &wb_connector->base; + struct drm_mode_config *config = &dev->mode_config; + int ret = create_writeback_properties(dev); + + if (ret != 0) + return ret; + + 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->fb) + drm_framebuffer_unreference(job->fb); + dma_fence_put(job->out_fence); +} +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 cf13842a6dbd..d7b0263cc5cf 100644 --- a/include/drm/drm_atomic.h +++ b/include/drm/drm_atomic.h @@ -594,6 +594,9 @@ 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 675cc3f8cf85..60c0ffb947d5 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -429,6 +429,19 @@ struct drm_connector_state { * protection. This is most commonly used for HDCP. */ unsigned int content_protection; + + /** + * @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 7569f22ffef6..de8881324f73 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -779,6 +779,21 @@ struct drm_mode_config { */ struct drm_property *panel_orientation_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_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index 3e76ca805b0f..636deaf52325 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -974,6 +974,17 @@ struct drm_connector_helper_funcs { */ int (*atomic_check)(struct drm_connector *connector, struct drm_connector_state *state); + + /** + * @atomic_commit: + * + * This hook is to be used by drivers implementing writeback connectors + * that need a point when to commit the writeback job to the hardware. + * + * This callback is used by the atomic modeset helpers. + */ + void (*atomic_commit)(struct drm_connector *connector, + struct drm_writeback_job *writeback_job); };

/** 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 2c575794fb52..7b47e184e95e 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -338,6 +338,7 @@ 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 {

Due to the fact that writeback connectors behave in a special way in DRM (they always report being disconnected) we might confuse some userspace. Add a client capability for writeback connectors that will filter them out for clients that don't understand the capability.

Re-requested-by: Sean Paul seanpaul@chromium.org Cc: Brian Starkey brian.starkey@arm.com Signed-off-by: Liviu Dudau liviu.dudau@arm.com --- drivers/gpu/drm/drm_ioctl.c | 5 +++++ drivers/gpu/drm/drm_mode_config.c | 5 +++++ include/drm/drm_file.h | 7 +++++++ include/uapi/drm/drm.h | 9 +++++++++ 4 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 02ffa0e8d77b..48895a469963 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -322,6 +322,11 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv) file_priv->atomic = req->value; file_priv->universal_planes = req->value; break; + case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS: + if (!file_priv->atomic || !drm_core_check_feature(dev, DRIVER_ATOMIC)) + return -EINVAL; + file_priv->writeback_connectors = req->value; + break; default: return -EINVAL; } diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index e5c653357024..21e353bd3948 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -145,6 +145,11 @@ int drm_mode_getresources(struct drm_device *dev, void *data, count = 0; connector_id = u64_to_user_ptr(card_res->connector_id_ptr); drm_for_each_connector_iter(connector, &conn_iter) { + /* only expose writeback connectors if userspace understands them */ + if (!file_priv->writeback_connectors && + (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)) + continue; + if (drm_lease_held(file_priv, connector->base.id)) { if (count < card_res->count_connectors && put_user(connector->base.id, connector_id + count)) { diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index 5176c3797680..2a09b3c8965c 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -181,6 +181,13 @@ struct drm_file { /** @atomic: True if client understands atomic properties. */ unsigned atomic:1;

+ /** + * @writeback_connectors: + * + * True if client understands writeback connectors + */ + unsigned writeback_connectors:1; + /** * @is_master: * diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 6fdff5945c8a..59f27ea928b4 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -680,6 +680,15 @@ struct drm_get_cap { */ #define DRM_CLIENT_CAP_ATOMIC 3

+/** + * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS + * + * If set to 1, the DRM core will expose special connectors to be used for + * writing back to memory the scene setup in the commit. Depends on client + * also supporting DRM_CLIENT_CAP_ATOMIC + */ +#define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS 4 + /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */ struct drm_set_client_cap { __u64 capability;