1/*	$NetBSD: ttm_bus_dma.c,v 1.10 2021/12/19 11:32:54 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: ttm_bus_dma.c,v 1.10 2021/12/19 11:32:54 riastradh Exp $");
34
35#include <sys/bus.h>
36
37#include <uvm/uvm_extern.h>
38
39#include <drm/bus_dma_hacks.h>
40#include <ttm/ttm_bo_driver.h>
41#include <ttm/ttm_page_alloc.h>
42
43/*
44 * ttm_bus_dma_populate(ttm_dma)
45 *
46 *	If ttm_dma is not already populated, wire its pages and load
47 *	its DMA map.  The wiring and loading are stable as long as the
48 *	associated bo is reserved.
49 *
50 *	Transitions from tt_unpopulated to tt_unbound.  Marks as wired,
51 *	a.k.a. !swapped.
52 */
53int
54ttm_bus_dma_populate(struct ttm_dma_tt *ttm_dma)
55{
56	int ret;
57
58	KASSERT(ttm_dma->ttm.state == tt_unpopulated);
59
60	/* If it's unpopulated, it can't be swapped.  */
61	KASSERT(!ISSET(ttm_dma->ttm.page_flags, TTM_PAGE_FLAG_SWAPPED));
62	/* Pretend it is now, for the sake of ttm_tt_wire.  */
63	ttm_dma->ttm.page_flags |= TTM_PAGE_FLAG_SWAPPED;
64
65	/* Wire the uvm pages and fill the ttm page array.  */
66	ret = ttm_tt_wire(&ttm_dma->ttm);
67	if (ret)
68		goto fail0;
69
70	/* Mark it populated but unbound.  */
71	ttm_dma->ttm.state = tt_unbound;
72
73	/* Mark it wired.  */
74	ttm_dma->ttm.page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
75
76	/* Load the DMA map.  */
77	/* XXX errno NetBSD->Linux */
78	ret = -bus_dmamap_load_pages(ttm_dma->ttm.bdev->dmat,
79	    ttm_dma->dma_address, ttm_dma->ttm.pages,
80	    (ttm_dma->ttm.num_pages << PAGE_SHIFT), BUS_DMA_NOWAIT);
81	if (ret)
82		goto fail1;
83
84	/* Success!  */
85	return 0;
86
87fail2: __unused
88	bus_dmamap_unload(ttm_dma->ttm.bdev->dmat, ttm_dma->dma_address);
89fail1:	KASSERT(ttm_dma->ttm.state == tt_unbound);
90	ttm_tt_unwire(&ttm_dma->ttm);
91	ttm_dma->ttm.state = tt_unpopulated;
92fail0:	KASSERT(ret);
93	return ret;
94}
95
96static void
97ttm_bus_dma_put(struct ttm_dma_tt *ttm_dma, int flags)
98{
99	struct uvm_object *const uobj = ttm_dma->ttm.swap_storage;
100	const size_t size = (ttm_dma->ttm.num_pages << PAGE_SHIFT);
101
102	/*
103	 * Can't be tt_bound -- still in use and needs to be removed
104	 * from GPU page tables.  Can't be tt_unpopulated -- if it
105	 * were, why are you hnadling this?  Hence tt_unbound.
106	 */
107	KASSERTMSG((ttm_dma->ttm.state == tt_unbound),
108	    "ttm_tt %p in invalid state for unpopulate/swapout: %d",
109	    &ttm_dma->ttm, (int)ttm_dma->ttm.state);
110
111	/* If pages are wired and loaded, unload and unwire them.  */
112	if (!ISSET(ttm_dma->ttm.page_flags, TTM_PAGE_FLAG_SWAPPED)) {
113		bus_dmamap_unload(ttm_dma->ttm.bdev->dmat,
114		    ttm_dma->dma_address);
115		ttm_tt_unwire(&ttm_dma->ttm);
116		ttm_dma->ttm.page_flags |= TTM_PAGE_FLAG_SWAPPED;
117	}
118
119	/* We are using uvm_aobj, which had better have a pgo_put.  */
120	KASSERT(uobj->pgops->pgo_put);
121
122	/* Release or deactivate the pages.  */
123	rw_enter(uobj->vmobjlock, RW_WRITER);
124	(void)(*uobj->pgops->pgo_put)(uobj, 0, size, flags);
125	/* pgo_put unlocks uobj->vmobjlock.  */
126
127	/* Mark it unpopulated.  */
128	ttm_dma->ttm.state = tt_unpopulated;
129}
130
131/*
132 * ttmm_bus_dma_unpopulate(ttm_dma)
133 *
134 *	Unload any DMA map, unwire any pages, and release any pages
135 *	associated with ttm_dma.
136 *
137 *	Transitions from tt_unbound to tt_unpopulated.  Marks as
138 *	unwired, a.k.a. swapped.
139 */
140void
141ttm_bus_dma_unpopulate(struct ttm_dma_tt *ttm_dma)
142{
143
144	ttm_bus_dma_put(ttm_dma, PGO_CLEANIT|PGO_FREE);
145}
146
147/*
148 * ttm_bus_dma_swapout(ttm_dma)
149 *
150 *	Unload any DMA map, unwire any pages, and deactivate any pages
151 *	associated with ttm_dma so that they can be swapped out, but
152 *	don't release them.
153 *
154 *	Transitions from tt_unbound to tt_unpopulated.  Marks as
155 *	unwired, a.k.a. swapped.
156 */
157void
158ttm_bus_dma_swapout(struct ttm_dma_tt *ttm_dma)
159{
160
161	ttm_bus_dma_put(ttm_dma, PGO_DEACTIVATE);
162}
163