dma-buf: nuke seqno-fence

# SPDX-License-Identifier: GPL-2.0-only

obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \

	 dma-resv.o seqno-fence.o

	 dma-resv.o

obj-$(CONFIG_DMABUF_HEAPS)	+= dma-heap.o

obj-$(CONFIG_DMABUF_HEAPS)	+= heaps/

obj-$(CONFIG_SYNC_FILE)		+= sync_file.o

// SPDX-License-Identifier: GPL-2.0-only

/*

 * seqno-fence, using a dma-buf to synchronize fencing

 *

 * Copyright (C) 2012 Texas Instruments

 * Copyright (C) 2012-2014 Canonical Ltd

 * Authors:

 *   Rob Clark <robdclark@gmail.com>

 *   Maarten Lankhorst <maarten.lankhorst@canonical.com>

 */

#include <linux/slab.h>

#include <linux/export.h>

#include <linux/seqno-fence.h>

static const char *seqno_fence_get_driver_name(struct dma_fence *fence)

{

	struct seqno_fence *seqno_fence = to_seqno_fence(fence);

	return seqno_fence->ops->get_driver_name(fence);

}

static const char *seqno_fence_get_timeline_name(struct dma_fence *fence)

{

	struct seqno_fence *seqno_fence = to_seqno_fence(fence);

	return seqno_fence->ops->get_timeline_name(fence);

}

static bool seqno_enable_signaling(struct dma_fence *fence)

{

	struct seqno_fence *seqno_fence = to_seqno_fence(fence);

	return seqno_fence->ops->enable_signaling(fence);

}

static bool seqno_signaled(struct dma_fence *fence)

{

	struct seqno_fence *seqno_fence = to_seqno_fence(fence);

	return seqno_fence->ops->signaled && seqno_fence->ops->signaled(fence);

}

static void seqno_release(struct dma_fence *fence)

{

	struct seqno_fence *f = to_seqno_fence(fence);

	dma_buf_put(f->sync_buf);

	if (f->ops->release)

		f->ops->release(fence);

	else

		dma_fence_free(&f->base);

}

static signed long seqno_wait(struct dma_fence *fence, bool intr,

			      signed long timeout)

{

	struct seqno_fence *f = to_seqno_fence(fence);

	return f->ops->wait(fence, intr, timeout);

}

const struct dma_fence_ops seqno_fence_ops = {

	.get_driver_name = seqno_fence_get_driver_name,

	.get_timeline_name = seqno_fence_get_timeline_name,

	.enable_signaling = seqno_enable_signaling,

	.signaled = seqno_signaled,

	.wait = seqno_wait,

	.release = seqno_release,

};

EXPORT_SYMBOL(seqno_fence_ops);

/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * seqno-fence, using a dma-buf to synchronize fencing

 *

 * Copyright (C) 2012 Texas Instruments

 * Copyright (C) 2012 Canonical Ltd

 * Authors:

 *   Rob Clark <robdclark@gmail.com>

 *   Maarten Lankhorst <maarten.lankhorst@canonical.com>

 */

#ifndef __LINUX_SEQNO_FENCE_H

#define __LINUX_SEQNO_FENCE_H

#include <linux/dma-fence.h>

#include <linux/dma-buf.h>

enum seqno_fence_condition {

	SEQNO_FENCE_WAIT_GEQUAL,

	SEQNO_FENCE_WAIT_NONZERO

};

struct seqno_fence {

	struct dma_fence base;

	const struct dma_fence_ops *ops;

	struct dma_buf *sync_buf;

	uint32_t seqno_ofs;

	enum seqno_fence_condition condition;

};

extern const struct dma_fence_ops seqno_fence_ops;

/**

 * to_seqno_fence - cast a fence to a seqno_fence

 * @fence: fence to cast to a seqno_fence

 *

 * Returns NULL if the fence is not a seqno_fence,

 * or the seqno_fence otherwise.

 */

static inline struct seqno_fence *

to_seqno_fence(struct dma_fence *fence)

{

	if (fence->ops != &seqno_fence_ops)

		return NULL;

	return container_of(fence, struct seqno_fence, base);

}

/**

 * seqno_fence_init - initialize a seqno fence

 * @fence: seqno_fence to initialize

 * @lock: pointer to spinlock to use for fence

 * @sync_buf: buffer containing the memory location to signal on

 * @context: the execution context this fence is a part of

 * @seqno_ofs: the offset within @sync_buf

 * @seqno: the sequence # to signal on

 * @cond: fence wait condition

 * @ops: the fence_ops for operations on this seqno fence

 *

 * This function initializes a struct seqno_fence with passed parameters,

 * and takes a reference on sync_buf which is released on fence destruction.

 *

 * A seqno_fence is a dma_fence which can complete in software when

 * enable_signaling is called, but it also completes when

 * (s32)((sync_buf)[seqno_ofs] - seqno) >= 0 is true

 *

 * The seqno_fence will take a refcount on the sync_buf until it's

 * destroyed, but actual lifetime of sync_buf may be longer if one of the

 * callers take a reference to it.

 *

 * Certain hardware have instructions to insert this type of wait condition

 * in the command stream, so no intervention from software would be needed.

 * This type of fence can be destroyed before completed, however a reference

 * on the sync_buf dma-buf can be taken. It is encouraged to re-use the same

 * dma-buf for sync_buf, since mapping or unmapping the sync_buf to the

 * device's vm can be expensive.

 *

 * It is recommended for creators of seqno_fence to call dma_fence_signal()

 * before destruction. This will prevent possible issues from wraparound at

 * time of issue vs time of check, since users can check dma_fence_is_signaled()

 * before submitting instructions for the hardware to wait on the fence.

 * However, when ops.enable_signaling is not called, it doesn't have to be

 * done as soon as possible, just before there's any real danger of seqno

 * wraparound.

 */

static inline void

seqno_fence_init(struct seqno_fence *fence, spinlock_t *lock,

		 struct dma_buf *sync_buf,  uint32_t context,

		 uint32_t seqno_ofs, uint32_t seqno,

		 enum seqno_fence_condition cond,

		 const struct dma_fence_ops *ops)

{

	BUG_ON(!fence || !sync_buf || !ops);

	BUG_ON(!ops->wait || !ops->enable_signaling ||

	       !ops->get_driver_name || !ops->get_timeline_name);

	/*

	 * ops is used in dma_fence_init for get_driver_name, so needs to be

	 * initialized first

	 */

	fence->ops = ops;

	dma_fence_init(&fence->base, &seqno_fence_ops, lock, context, seqno);

	get_dma_buf(sync_buf);

	fence->sync_buf = sync_buf;

	fence->seqno_ofs = seqno_ofs;

	fence->condition = cond;

}

#endif /* __LINUX_SEQNO_FENCE_H */