// SPDX-License-Identifier: MIT
/*
 * Copyright 2024 Advanced Micro Devices, Inc.
 *
 * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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 <linux/sched.h>
#include <drm/drm_exec.h>
#include "amdgpu.h"

#define work_to_evf_mgr(w, name) container_of(w, struct amdgpu_eviction_fence_mgr, name)
#define evf_mgr_to_fpriv(e) container_of(e, struct amdgpu_fpriv, evf_mgr)

static const char *
amdgpu_eviction_fence_get_driver_name(struct dma_fence *fence)
{
	return "amdgpu_eviction_fence";
}

static const char *
amdgpu_eviction_fence_get_timeline_name(struct dma_fence *f)
{
	struct amdgpu_eviction_fence *ef;

	ef = container_of(f, struct amdgpu_eviction_fence, base);
	return ef->timeline_name;
}

int
amdgpu_eviction_fence_replace_fence(struct amdgpu_eviction_fence_mgr *evf_mgr,
				    struct drm_exec *exec)
{
	struct amdgpu_eviction_fence *old_ef, *new_ef;
	struct drm_gem_object *obj;
	unsigned long index;
	int ret;

	if (evf_mgr->ev_fence &&
	    !dma_fence_is_signaled(&evf_mgr->ev_fence->base))
		return 0;
	/*
	 * Steps to replace eviction fence:
	 * * lock all objects in exec (caller)
	 * * create a new eviction fence
	 * * update new eviction fence in evf_mgr
	 * * attach the new eviction fence to BOs
	 * * release the old fence
	 * * unlock the objects (caller)
	 */
	new_ef = amdgpu_eviction_fence_create(evf_mgr);
	if (!new_ef) {
		DRM_ERROR("Failed to create new eviction fence\n");
		return -ENOMEM;
	}

	/* Update the eviction fence now */
	spin_lock(&evf_mgr->ev_fence_lock);
	old_ef = evf_mgr->ev_fence;
	evf_mgr->ev_fence = new_ef;
	spin_unlock(&evf_mgr->ev_fence_lock);

	/* Attach the new fence */
	drm_exec_for_each_locked_object(exec, index, obj) {
		struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

		if (!bo)
			continue;
		ret = amdgpu_eviction_fence_attach(evf_mgr, bo);
		if (ret) {
			DRM_ERROR("Failed to attch new eviction fence\n");
			goto free_err;
		}
	}

	/* Free old fence */
	if (old_ef)
		dma_fence_put(&old_ef->base);
	return 0;

free_err:
	kfree(new_ef);
	return ret;
}

static void
amdgpu_eviction_fence_suspend_worker(struct work_struct *work)
{
	struct amdgpu_eviction_fence_mgr *evf_mgr = work_to_evf_mgr(work, suspend_work.work);
	struct amdgpu_fpriv *fpriv = evf_mgr_to_fpriv(evf_mgr);
	struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr;
	struct amdgpu_eviction_fence *ev_fence;

	mutex_lock(&uq_mgr->userq_mutex);
	spin_lock(&evf_mgr->ev_fence_lock);
	ev_fence = evf_mgr->ev_fence;
	if (ev_fence)
		dma_fence_get(&ev_fence->base);
	else
		goto unlock;
	spin_unlock(&evf_mgr->ev_fence_lock);

	amdgpu_userq_evict(uq_mgr, ev_fence);

	mutex_unlock(&uq_mgr->userq_mutex);
	dma_fence_put(&ev_fence->base);
	return;

unlock:
	spin_unlock(&evf_mgr->ev_fence_lock);
	mutex_unlock(&uq_mgr->userq_mutex);
}

static bool amdgpu_eviction_fence_enable_signaling(struct dma_fence *f)
{
	struct amdgpu_eviction_fence_mgr *evf_mgr;
	struct amdgpu_eviction_fence *ev_fence;

	if (!f)
		return true;

	ev_fence = to_ev_fence(f);
	evf_mgr = ev_fence->evf_mgr;

	schedule_delayed_work(&evf_mgr->suspend_work, 0);
	return true;
}

static const struct dma_fence_ops amdgpu_eviction_fence_ops = {
	.use_64bit_seqno = true,
	.get_driver_name = amdgpu_eviction_fence_get_driver_name,
	.get_timeline_name = amdgpu_eviction_fence_get_timeline_name,
	.enable_signaling = amdgpu_eviction_fence_enable_signaling,
};

void amdgpu_eviction_fence_signal(struct amdgpu_eviction_fence_mgr *evf_mgr,
				  struct amdgpu_eviction_fence *ev_fence)
{
	spin_lock(&evf_mgr->ev_fence_lock);
	dma_fence_signal(&ev_fence->base);
	spin_unlock(&evf_mgr->ev_fence_lock);
}

struct amdgpu_eviction_fence *
amdgpu_eviction_fence_create(struct amdgpu_eviction_fence_mgr *evf_mgr)
{
	struct amdgpu_eviction_fence *ev_fence;

	ev_fence = kzalloc(sizeof(*ev_fence), GFP_KERNEL);
	if (!ev_fence)
		return NULL;

	ev_fence->evf_mgr = evf_mgr;
	get_task_comm(ev_fence->timeline_name, current);
	spin_lock_init(&ev_fence->lock);
	dma_fence_init(&ev_fence->base, &amdgpu_eviction_fence_ops,
		       &ev_fence->lock, evf_mgr->ev_fence_ctx,
		       atomic_inc_return(&evf_mgr->ev_fence_seq));
	return ev_fence;
}

void amdgpu_eviction_fence_destroy(struct amdgpu_eviction_fence_mgr *evf_mgr)
{
	struct amdgpu_eviction_fence *ev_fence;

	/* Wait for any pending work to execute */
	flush_delayed_work(&evf_mgr->suspend_work);

	spin_lock(&evf_mgr->ev_fence_lock);
	ev_fence = evf_mgr->ev_fence;
	spin_unlock(&evf_mgr->ev_fence_lock);

	if (!ev_fence)
		return;

	dma_fence_wait(&ev_fence->base, false);

	/* Last unref of ev_fence */
	dma_fence_put(&ev_fence->base);
}

int amdgpu_eviction_fence_attach(struct amdgpu_eviction_fence_mgr *evf_mgr,
				 struct amdgpu_bo *bo)
{
	struct amdgpu_eviction_fence *ev_fence;
	struct dma_resv *resv = bo->tbo.base.resv;
	int ret;

	if (!resv)
		return 0;

	ret = dma_resv_reserve_fences(resv, 1);
	if (ret) {
		DRM_DEBUG_DRIVER("Failed to resv fence space\n");
		return ret;
	}

	spin_lock(&evf_mgr->ev_fence_lock);
	ev_fence = evf_mgr->ev_fence;
	if (ev_fence)
		dma_resv_add_fence(resv, &ev_fence->base, DMA_RESV_USAGE_BOOKKEEP);
	spin_unlock(&evf_mgr->ev_fence_lock);

	return 0;
}

void amdgpu_eviction_fence_detach(struct amdgpu_eviction_fence_mgr *evf_mgr,
				  struct amdgpu_bo *bo)
{
	struct dma_fence *stub = dma_fence_get_stub();

	dma_resv_replace_fences(bo->tbo.base.resv, evf_mgr->ev_fence_ctx,
				stub, DMA_RESV_USAGE_BOOKKEEP);
	dma_fence_put(stub);
}

int amdgpu_eviction_fence_init(struct amdgpu_eviction_fence_mgr *evf_mgr)
{
	/* This needs to be done one time per open */
	atomic_set(&evf_mgr->ev_fence_seq, 0);
	evf_mgr->ev_fence_ctx = dma_fence_context_alloc(1);
	spin_lock_init(&evf_mgr->ev_fence_lock);

	INIT_DELAYED_WORK(&evf_mgr->suspend_work, amdgpu_eviction_fence_suspend_worker);
	return 0;
}