1/*	$NetBSD: radeon_mn.c,v 1.3 2021/12/18 23:45:43 riastradh Exp $	*/
2
3/*
4 * Copyright 2014 Advanced Micro Devices, Inc.
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
21 * USE OR OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * The above copyright notice and this permission notice (including the
24 * next paragraph) shall be included in all copies or substantial portions
25 * of the Software.
26 *
27 */
28/*
29 * Authors:
30 *    Christian K��nig <christian.koenig@amd.com>
31 */
32
33#include <sys/cdefs.h>
34__KERNEL_RCSID(0, "$NetBSD: radeon_mn.c,v 1.3 2021/12/18 23:45:43 riastradh Exp $");
35
36#include <linux/firmware.h>
37#include <linux/module.h>
38#include <linux/mmu_notifier.h>
39
40#include <drm/drm.h>
41
42#include "radeon.h"
43
44/**
45 * radeon_mn_invalidate - callback to notify about mm change
46 *
47 * @mn: our notifier
48 * @range: the VMA under invalidation
49 *
50 * We block for all BOs between start and end to be idle and
51 * unmap them by move them into system domain again.
52 */
53static bool radeon_mn_invalidate(struct mmu_interval_notifier *mn,
54				 const struct mmu_notifier_range *range,
55				 unsigned long cur_seq)
56{
57	struct radeon_bo *bo = container_of(mn, struct radeon_bo, notifier);
58	struct ttm_operation_ctx ctx = { false, false };
59	long r;
60
61	if (!bo->tbo.ttm || bo->tbo.ttm->state != tt_bound)
62		return true;
63
64	if (!mmu_notifier_range_blockable(range))
65		return false;
66
67	r = radeon_bo_reserve(bo, true);
68	if (r) {
69		DRM_ERROR("(%ld) failed to reserve user bo\n", r);
70		return true;
71	}
72
73	r = dma_resv_wait_timeout_rcu(bo->tbo.base.resv, true, false,
74				      MAX_SCHEDULE_TIMEOUT);
75	if (r <= 0)
76		DRM_ERROR("(%ld) failed to wait for user bo\n", r);
77
78	radeon_ttm_placement_from_domain(bo, RADEON_GEM_DOMAIN_CPU);
79	r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
80	if (r)
81		DRM_ERROR("(%ld) failed to validate user bo\n", r);
82
83	radeon_bo_unreserve(bo);
84	return true;
85}
86
87static const struct mmu_interval_notifier_ops radeon_mn_ops = {
88	.invalidate = radeon_mn_invalidate,
89};
90
91/**
92 * radeon_mn_register - register a BO for notifier updates
93 *
94 * @bo: radeon buffer object
95 * @addr: userptr addr we should monitor
96 *
97 * Registers an MMU notifier for the given BO at the specified address.
98 * Returns 0 on success, -ERRNO if anything goes wrong.
99 */
100int radeon_mn_register(struct radeon_bo *bo, unsigned long addr)
101{
102	int ret;
103
104	ret = mmu_interval_notifier_insert(&bo->notifier, current->mm, addr,
105					   radeon_bo_size(bo), &radeon_mn_ops);
106	if (ret)
107		return ret;
108
109	/*
110	 * FIXME: radeon appears to allow get_user_pages to run during
111	 * invalidate_range_start/end, which is not a safe way to read the
112	 * PTEs. It should use the mmu_interval_read_begin() scheme around the
113	 * get_user_pages to ensure that the PTEs are read properly
114	 */
115	mmu_interval_read_begin(&bo->notifier);
116	return 0;
117}
118
119/**
120 * radeon_mn_unregister - unregister a BO for notifier updates
121 *
122 * @bo: radeon buffer object
123 *
124 * Remove any registration of MMU notifier updates from the buffer object.
125 */
126void radeon_mn_unregister(struct radeon_bo *bo)
127{
128	if (!bo->notifier.mm)
129		return;
130	mmu_interval_notifier_remove(&bo->notifier);
131	bo->notifier.mm = NULL;
132}
133