[PATCH 1/9] drm: add flip-work helper
Rob Clark
robdclark at gmail.com
Wed Aug 7 10:41:19 PDT 2013
A small helper to queue up work to do, from workqueue context, after a
flip. Typically useful to defer unreffing buffers that may be read by
the display controller until vblank.
Signed-off-by: Rob Clark <robdclark at gmail.com>
---
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_flip_work.c | 124 ++++++++++++++++++++++++++++++++++++++++
include/drm/drm_flip_work.h | 71 +++++++++++++++++++++++
3 files changed, 196 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/drm_flip_work.c
create mode 100644 include/drm/drm_flip_work.h
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index d943b94..2aaf082 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -13,7 +13,7 @@ drm-y := drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
drm_crtc.o drm_modes.o drm_edid.o \
drm_info.o drm_debugfs.o drm_encoder_slave.o \
drm_trace_points.o drm_global.o drm_prime.o \
- drm_rect.o drm_vma_manager.o
+ drm_rect.o drm_vma_manager.o drm_flip_work.o
drm-$(CONFIG_COMPAT) += drm_ioc32.o
drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
diff --git a/drivers/gpu/drm/drm_flip_work.c b/drivers/gpu/drm/drm_flip_work.c
new file mode 100644
index 0000000..e788882
--- /dev/null
+++ b/drivers/gpu/drm/drm_flip_work.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2013 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "drmP.h"
+#include "drm_flip_work.h"
+
+/**
+ * drm_flip_work_queue - queue work
+ * @work: the flip-work
+ * @val: the value to queue
+ *
+ * Queues work, that will later be run (passed back to drm_flip_func_t
+ * func) on a work queue after drm_flip_work_commit() is called.
+ */
+void drm_flip_work_queue(struct drm_flip_work *work, void *val)
+{
+ if (kfifo_put(&work->fifo, (const void **)&val)) {
+ atomic_inc(&work->pending);
+ } else {
+ DRM_ERROR("%s fifo full!\n", work->name);
+ work->func(work, val);
+ }
+}
+EXPORT_SYMBOL(drm_flip_work_queue);
+
+/**
+ * drm_flip_work_commit - commit queued work
+ * @work: the flip-work
+ * @wq: the work-queue to run the queued work on
+ *
+ * Trigger work previously queued by drm_flip_work_queue() to run
+ * on a workqueue. The typical usage would be to queue work (via
+ * drm_flip_work_queue()) at any point (from vblank irq and/or
+ * prior), and then from vblank irq commit the queued work.
+ */
+void drm_flip_work_commit(struct drm_flip_work *work,
+ struct workqueue_struct *wq)
+{
+ uint32_t pending = atomic_read(&work->pending);
+ atomic_add(pending, &work->count);
+ atomic_sub(pending, &work->pending);
+ queue_work(wq, &work->worker);
+}
+EXPORT_SYMBOL(drm_flip_work_commit);
+
+static void flip_worker(struct work_struct *w)
+{
+ struct drm_flip_work *work = container_of(w, struct drm_flip_work, worker);
+ uint32_t count = atomic_read(&work->count);
+ void *val = NULL;
+
+ atomic_sub(count, &work->count);
+
+ while(count--)
+ if (!WARN_ON(!kfifo_get(&work->fifo, &val)))
+ work->func(work, val);
+}
+
+/**
+ * drm_flip_work_init - initialize flip-work
+ * @work: the flip-work to initialize
+ * @size: the max queue depth
+ * @name: debug name
+ * @func: the callback work function
+ *
+ * Initializes/allocates resources for the flip-work
+ *
+ * RETURNS:
+ * Zero on success, error code on failure.
+ */
+int drm_flip_work_init(struct drm_flip_work *work, int size,
+ const char *name, drm_flip_func_t func)
+{
+ int ret;
+
+ work->name = name;
+ atomic_set(&work->count, 0);
+ atomic_set(&work->pending, 0);
+ work->func = func;
+
+ ret = kfifo_alloc(&work->fifo, size, GFP_KERNEL);
+ if (ret) {
+ DRM_ERROR("could not allocate %s fifo\n", name);
+ return ret;
+ }
+
+ INIT_WORK(&work->worker, flip_worker);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_flip_work_init);
+
+/**
+ * drm_flip_work_cleanup - cleans up flip-work
+ * @work: the flip-work to cleanup
+ *
+ * Destroy resources allocated for the flip-work
+ */
+void drm_flip_work_cleanup(struct drm_flip_work *work)
+{
+ WARN_ON(!kfifo_is_empty(&work->fifo));
+ kfifo_free(&work->fifo);
+}
+EXPORT_SYMBOL(drm_flip_work_cleanup);
diff --git a/include/drm/drm_flip_work.h b/include/drm/drm_flip_work.h
new file mode 100644
index 0000000..7d3840b
--- /dev/null
+++ b/include/drm/drm_flip_work.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2013 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef DRM_FLIP_WORK_H
+#define DRM_FLIP_WORK_H
+
+#include <linux/kfifo.h>
+#include <linux/workqueue.h>
+
+/**
+ * DOC: flip utils
+ *
+ * Util to queue up work to run from work-queue context after flip/vblank.
+ * Typically this can be used to defer unref of framebuffer's, cursor
+ * bo's, etc until after vblank. The APIs are all safe (and lockless)
+ * for up to one producer and once consumer at a time. The single-consumer
+ * aspect is ensured by committing the queued work to a single work-queue.
+ */
+
+struct drm_flip_work;
+
+/**
+ * drm_flip_func_t - callback function
+ *
+ * @work: the flip work
+ * @val: value queued via drm_flip_work_queue()
+ *
+ * Callback function to be called for each of the queue'd work items after
+ * drm_flip_work_commit() is called.
+ */
+typedef void (*drm_flip_func_t)(struct drm_flip_work *work, void *val);
+
+/**
+ * struct drm_flip_work - flip work queue
+ */
+struct drm_flip_work {
+ const char *name;
+ atomic_t pending, count;
+ drm_flip_func_t func;
+ struct work_struct worker;
+ DECLARE_KFIFO_PTR(fifo, void *);
+};
+
+void drm_flip_work_queue(struct drm_flip_work *work, void *val);
+void drm_flip_work_commit(struct drm_flip_work *work,
+ struct workqueue_struct *wq);
+int drm_flip_work_init(struct drm_flip_work *work, int size,
+ const char *name, drm_flip_func_t func);
+void drm_flip_work_cleanup(struct drm_flip_work *work);
+
+#endif /* DRM_FLIP_WORK_H */
--
1.8.3.1
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