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@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 */