v4.19.13 snapshot.
diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
new file mode 100644
index 0000000..c20e6fe
--- /dev/null
+++ b/drivers/gpu/drm/drm_writeback.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * (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>
+#include <linux/dma-fence.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 are visible to userspace only when the client sets
+ * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS.
+ *
+ * * 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.
+ *
+ * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
+ * makes no attempt to remove it from active use by the connector. This is
+ * because no method is provided to abort a writeback operation, and in any
+ * case making a new commit whilst a writeback is ongoing is undefined (see
+ * WRITEBACK_OUT_FENCE_PTR below). As soon as the current writeback is finished,
+ * the framebuffer will automatically no longer be in active use. As it will
+ * also have already been removed from the framebuffer list, there will be no
+ * way for any userspace application to retrieve a reference to it in the
+ * intervening period.
+ *
+ * Writeback connectors have some additional properties, which userspace
+ * can use to query and control them:
+ *
+ * "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.
+ *
+ * "WRITEBACK_OUT_FENCE_PTR":
+ * Userspace can use this property to provide a pointer for the kernel to
+ * fill with a sync_file file descriptor, which will signal once the
+ * writeback is finished. The value should be the address of a 32-bit
+ * signed integer, cast to a u64.
+ * Userspace should wait for this fence to signal before making another
+ * commit affecting any of the same CRTCs, Planes or Connectors.
+ * **Failure to do so will result in undefined behaviour.**
+ * For this reason it is strongly recommended that all userspace
+ * applications making use of writeback connectors *always* retrieve an
+ * out-fence for the commit and use it appropriately.
+ * From userspace, this property will always read as zero.
+ */
+
+#define fence_to_wb_connector(x) container_of(x->lock, \
+ struct drm_writeback_connector, \
+ fence_lock)
+
+static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence)
+{
+ struct drm_writeback_connector *wb_connector =
+ fence_to_wb_connector(fence);
+
+ return wb_connector->base.dev->driver->name;
+}
+
+static const char *
+drm_writeback_fence_get_timeline_name(struct dma_fence *fence)
+{
+ struct drm_writeback_connector *wb_connector =
+ fence_to_wb_connector(fence);
+
+ return wb_connector->timeline_name;
+}
+
+static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence)
+{
+ return true;
+}
+
+static const struct dma_fence_ops drm_writeback_fence_ops = {
+ .get_driver_name = drm_writeback_fence_get_driver_name,
+ .get_timeline_name = drm_writeback_fence_get_timeline_name,
+ .enable_signaling = drm_writeback_fence_enable_signaling,
+ .wait = dma_fence_default_wait,
+};
+
+static int create_writeback_properties(struct drm_device *dev)
+{
+ struct drm_property *prop;
+
+ 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;
+ }
+
+ if (!dev->mode_config.writeback_out_fence_ptr_property) {
+ prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+ "WRITEBACK_OUT_FENCE_PTR", 0,
+ U64_MAX);
+ if (!prop)
+ return -ENOMEM;
+ dev->mode_config.writeback_out_fence_ptr_property = prop;
+ }
+
+ return 0;
+}
+
+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_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);
+
+ wb_connector->fence_context = dma_fence_context_alloc(1);
+ spin_lock_init(&wb_connector->fence_lock);
+ snprintf(wb_connector->timeline_name,
+ sizeof(wb_connector->timeline_name),
+ "CONNECTOR:%d-%s", connector->base.id, connector->name);
+
+ drm_object_attach_property(&connector->base,
+ config->writeback_out_fence_ptr_property, 0);
+
+ drm_object_attach_property(&connector->base,
+ config->writeback_fb_id_property, 0);
+
+ 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_blob_put(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);
+
+/*
+ * @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_framebuffer_put(job->fb);
+ kfree(job);
+}
+
+
+/**
+ * drm_writeback_signal_completion - Signal the completion of a writeback job
+ * @wb_connector: The writeback connector whose job is complete
+ * @status: Status code to set in the writeback out_fence (0 for success)
+ *
+ * Drivers should call this to signal the completion of a previously queued
+ * writeback job. It should be called as soon as possible after the hardware
+ * 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,
+ int status)
+{
+ 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);
+ if (job->out_fence) {
+ if (status)
+ dma_fence_set_error(job->out_fence, status);
+ dma_fence_signal(job->out_fence);
+ dma_fence_put(job->out_fence);
+ }
+ }
+ spin_unlock_irqrestore(&wb_connector->job_lock, flags);
+
+ if (WARN_ON(!job))
+ return;
+
+ INIT_WORK(&job->cleanup_work, cleanup_work);
+ queue_work(system_long_wq, &job->cleanup_work);
+}
+EXPORT_SYMBOL(drm_writeback_signal_completion);
+
+struct dma_fence *
+drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector)
+{
+ struct dma_fence *fence;
+
+ if (WARN_ON(wb_connector->base.connector_type !=
+ DRM_MODE_CONNECTOR_WRITEBACK))
+ return NULL;
+
+ fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+ if (!fence)
+ return NULL;
+
+ dma_fence_init(fence, &drm_writeback_fence_ops,
+ &wb_connector->fence_lock, wb_connector->fence_context,
+ ++wb_connector->fence_seqno);
+
+ return fence;
+}
+EXPORT_SYMBOL(drm_writeback_get_out_fence);