1 /* $NetBSD: drm_vm.c,v 1.13 2022/07/06 01:12:45 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2013 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: drm_vm.c,v 1.13 2022/07/06 01:12:45 riastradh Exp $");
34
35 #include <sys/types.h>
36 #include <sys/conf.h>
37
38 #include <uvm/uvm.h>
39 #include <uvm/uvm_extern.h>
40 #include <uvm/uvm_device.h>
41
42 #include <linux/capability.h>
43
44 #include <drm/drm_device.h>
45 #include <drm/drm_file.h>
46 #include <drm/drm_legacy.h>
47
48 static paddr_t drm_legacy_mmap_paddr_locked(struct drm_device *, off_t, int);
49 static paddr_t drm_legacy_mmap_dma_paddr(struct drm_device *, off_t, int);
50 static paddr_t drm_legacy_mmap_map_paddr(struct drm_device *,
51 struct drm_local_map *, off_t, int);
52
53 int
drm_legacy_mmap_object(struct drm_device * dev,off_t offset,size_t size,int prot,struct uvm_object ** uobjp,voff_t * uoffsetp,struct file * file __unused)54 drm_legacy_mmap_object(struct drm_device *dev, off_t offset, size_t size,
55 int prot, struct uvm_object **uobjp, voff_t *uoffsetp,
56 struct file *file __unused)
57 {
58 devmajor_t maj = cdevsw_lookup_major(&drm_cdevsw);
59 dev_t devno = makedev(maj, dev->primary->index);
60 struct uvm_object *uobj;
61
62 KASSERT(offset == (offset & ~(PAGE_SIZE-1)));
63 KASSERT(size > 0);
64
65 /*
66 * Attach the device. The size and offset are used only for
67 * access checks; offset does not become a base address for the
68 * subsequent uvm_map, hence we set *uoffsetp to offset, not 0.
69 */
70 uobj = udv_attach(devno, prot, offset, size);
71 if (uobj == NULL)
72 return -EINVAL;
73
74 *uobjp = uobj;
75 *uoffsetp = offset;
76 return 0;
77 }
78
79 paddr_t
drm_legacy_mmap_paddr(struct drm_device * dev,off_t byte_offset,int prot)80 drm_legacy_mmap_paddr(struct drm_device *dev, off_t byte_offset, int prot)
81 {
82 paddr_t paddr;
83
84 if (byte_offset != (byte_offset & ~(PAGE_SIZE-1)))
85 return -1;
86
87 mutex_lock(&dev->struct_mutex);
88 paddr = drm_legacy_mmap_paddr_locked(dev, byte_offset, prot);
89 mutex_unlock(&dev->struct_mutex);
90
91 return paddr;
92 }
93
94 static paddr_t
drm_legacy_mmap_paddr_locked(struct drm_device * dev,off_t byte_offset,int prot)95 drm_legacy_mmap_paddr_locked(struct drm_device *dev, off_t byte_offset,
96 int prot)
97 {
98 const off_t page_offset = (byte_offset >> PAGE_SHIFT);
99 struct drm_hash_item *hash;
100
101 KASSERT(mutex_is_locked(&dev->struct_mutex));
102 KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1)));
103
104 if ((dev->dma != NULL) &&
105 (0 <= byte_offset) &&
106 (page_offset <= dev->dma->page_count))
107 return drm_legacy_mmap_dma_paddr(dev, byte_offset, prot);
108
109 if (drm_ht_find_item(&dev->map_hash, page_offset, &hash))
110 return -1;
111
112 struct drm_local_map *const map = drm_hash_entry(hash,
113 struct drm_map_list, hash)->map;
114 if (map == NULL)
115 return -1;
116
117 /*
118 * XXX FreeBSD drops the mutex at this point, which would be
119 * nice, to allow sleeping in bus_dma cruft, but I don't know
120 * what guarantees the map will continue to exist.
121 */
122
123 if (ISSET(map->flags, _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))
124 return -1;
125
126 if (!(map->offset <= byte_offset))
127 return -1;
128 if (map->size < (map->offset - byte_offset))
129 return -1;
130
131 return drm_legacy_mmap_map_paddr(dev, map, (byte_offset - map->offset),
132 prot);
133 }
134
135 static paddr_t
drm_legacy_mmap_dma_paddr(struct drm_device * dev,off_t byte_offset,int prot)136 drm_legacy_mmap_dma_paddr(struct drm_device *dev, off_t byte_offset, int prot)
137 {
138 const off_t page_offset = (byte_offset >> PAGE_SHIFT);
139
140 KASSERT(mutex_is_locked(&dev->struct_mutex));
141 KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1)));
142 KASSERT(page_offset <= dev->dma->page_count);
143
144 if (dev->dma->pagelist == NULL)
145 return (paddr_t)-1;
146
147 return dev->dma->pagelist[page_offset];
148 }
149
150 static paddr_t
drm_legacy_mmap_map_paddr(struct drm_device * dev,struct drm_local_map * map,off_t byte_offset,int prot)151 drm_legacy_mmap_map_paddr(struct drm_device *dev, struct drm_local_map *map,
152 off_t byte_offset, int prot)
153 {
154 int flags = 0;
155
156 KASSERT(byte_offset <= map->size);
157
158 switch (map->type) {
159 case _DRM_FRAME_BUFFER:
160 case _DRM_AGP:
161 flags |= BUS_SPACE_MAP_PREFETCHABLE;
162 /* Fall through. */
163
164 case _DRM_REGISTERS:
165 flags |= BUS_SPACE_MAP_LINEAR; /* XXX Why? */
166
167 return bus_space_mmap(map->lm_data.bus_space.bst, map->offset,
168 byte_offset, prot, flags);
169
170 case _DRM_CONSISTENT: {
171 struct drm_dma_handle *const dmah = map->lm_data.dmah;
172
173 return bus_dmamem_mmap(dev->dmat, &dmah->dmah_seg, 1,
174 byte_offset, prot,
175 /* XXX BUS_DMA_WAITOK? We're holding a mutex... */
176 /* XXX What else? BUS_DMA_COHERENT? */
177 (BUS_DMA_WAITOK | BUS_DMA_NOCACHE));
178 }
179
180 case _DRM_SCATTER_GATHER: {
181 struct drm_sg_mem *const sg = dev->sg;
182
183 #if 0 /* XXX */
184 KASSERT(sg == map->lm_data.sg);
185 #endif
186
187 return bus_dmamem_mmap(dev->dmat, sg->sg_segs, sg->sg_nsegs,
188 byte_offset, prot,
189 /* XXX BUS_DMA_WAITOK? We're holding a mutex... */
190 /* XXX What else? BUS_DMA_COHERENT? */
191 (BUS_DMA_WAITOK | BUS_DMA_NOCACHE));
192 }
193
194 case _DRM_SHM:
195 default:
196 return (paddr_t)-1;
197 }
198 }
199