1 | /* $NetBSD: drm_scatter.c,v 1.3 2014/07/16 20:56:25 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_scatter.c,v 1.3 2014/07/16 20:56:25 riastradh Exp $" ); |
34 | |
35 | #include <sys/types.h> |
36 | #include <sys/bus.h> |
37 | #include <sys/errno.h> |
38 | #include <sys/systm.h> |
39 | |
40 | #include <linux/slab.h> |
41 | |
42 | #include <drm/drmP.h> |
43 | |
44 | static int drm_sg_alloc_mem(struct drm_device *, size_t, |
45 | struct drm_sg_mem **); |
46 | static void drm_sg_free_mem(struct drm_device *, struct drm_sg_mem *); |
47 | |
48 | int |
49 | drm_sg_alloc(struct drm_device *dev, void *data, |
50 | struct drm_file *file __unused) |
51 | { |
52 | struct drm_scatter_gather *const request = data; |
53 | struct drm_sg_mem *sg; |
54 | int error; |
55 | |
56 | /* |
57 | * XXX Should not hold this mutex during drm_sg_alloc. For |
58 | * now, we'll just use non-blocking allocations. |
59 | */ |
60 | KASSERT(mutex_is_locked(&drm_global_mutex)); |
61 | |
62 | /* |
63 | * Sanity-check the inputs. |
64 | */ |
65 | if (!drm_core_check_feature(dev, DRIVER_SG)) |
66 | return -ENODEV; |
67 | if (dev->sg != NULL) |
68 | return -EBUSY; |
69 | if (request->size > 0xffffffffUL) |
70 | return -ENOMEM; |
71 | |
72 | /* |
73 | * Do the allocation. |
74 | * |
75 | * XXX Would it be safe to drop drm_global_mutex here to avoid |
76 | * holding it during allocation? |
77 | */ |
78 | error = drm_sg_alloc_mem(dev, request->size, &sg); |
79 | if (error) |
80 | return error; |
81 | |
82 | /* Set it up to be the device's scatter-gather memory. */ |
83 | dev->sg = sg; |
84 | |
85 | /* Success! */ |
86 | request->handle = sg->handle; |
87 | return 0; |
88 | } |
89 | |
90 | int |
91 | drm_sg_free(struct drm_device *dev, void *data, struct drm_file *file) |
92 | { |
93 | struct drm_scatter_gather *const request = data; |
94 | struct drm_sg_mem *sg; |
95 | |
96 | KASSERT(mutex_is_locked(&drm_global_mutex)); |
97 | |
98 | /* |
99 | * Sanity-check the inputs. |
100 | */ |
101 | if (!drm_core_check_feature(dev, DRIVER_SG)) |
102 | return -ENODEV; |
103 | |
104 | sg = dev->sg; |
105 | if (sg == NULL) |
106 | return -ENXIO; |
107 | if (sg->handle != request->handle) |
108 | return -EINVAL; |
109 | |
110 | /* Remove dev->sg. */ |
111 | dev->sg = NULL; |
112 | |
113 | /* Free it. */ |
114 | drm_sg_free_mem(dev, sg); |
115 | |
116 | /* Success! */ |
117 | return 0; |
118 | } |
119 | |
120 | void |
121 | drm_legacy_sg_cleanup(struct drm_device *dev) |
122 | { |
123 | |
124 | if (!drm_core_check_feature(dev, DRIVER_SG)) |
125 | return; |
126 | if (dev->sg == NULL) |
127 | return; |
128 | if (drm_core_check_feature(dev, DRIVER_MODESET)) |
129 | return; |
130 | |
131 | drm_sg_free_mem(dev, dev->sg); |
132 | } |
133 | |
134 | static int |
135 | drm_sg_alloc_mem(struct drm_device *dev, size_t size, struct drm_sg_mem **sgp) |
136 | { |
137 | int nsegs; |
138 | int error; |
139 | |
140 | KASSERT(drm_core_check_feature(dev, DRIVER_SG)); |
141 | |
142 | KASSERT(size <= (size_t)0xffffffffUL); /* XXX 32-bit sizes only? */ |
143 | const size_t nbytes = PAGE_ALIGN(size); |
144 | const size_t npages = nbytes >> PAGE_SHIFT; |
145 | KASSERT(npages <= (size_t)INT_MAX); |
146 | |
147 | /* |
148 | * Allocate a drm_sg_mem record. |
149 | */ |
150 | struct drm_sg_mem *const sg = |
151 | kmem_zalloc(offsetof(struct drm_sg_mem, sg_segs[npages]), |
152 | KM_NOSLEEP); |
153 | if (sg == NULL) |
154 | return -ENOMEM; |
155 | sg->sg_tag = dev->dmat; |
156 | sg->sg_nsegs_max = (unsigned int)npages; |
157 | |
158 | /* |
159 | * Allocate the requested amount of DMA-safe memory. |
160 | */ |
161 | KASSERT(sg->sg_nsegs_max <= (unsigned int)INT_MAX); |
162 | /* XXX errno NetBSD->Linux */ |
163 | error = -bus_dmamem_alloc(sg->sg_tag, nbytes, PAGE_SIZE, 0, |
164 | sg->sg_segs, (int)sg->sg_nsegs_max, &nsegs, BUS_DMA_NOWAIT); |
165 | if (error) |
166 | goto fail0; |
167 | KASSERT(0 <= nsegs); |
168 | sg->sg_nsegs = (unsigned int)nsegs; |
169 | |
170 | /* |
171 | * XXX Old drm passed DRM_BUS_NOWAIT below but BUS_DMA_WAITOK |
172 | * above. WTF? |
173 | */ |
174 | |
175 | /* |
176 | * Map the DMA-safe memory into kernel virtual address space. |
177 | */ |
178 | /* XXX errno NetBSD->Linux */ |
179 | error = -bus_dmamem_map(sg->sg_tag, sg->sg_segs, nsegs, nbytes, |
180 | &sg->virtual, |
181 | (BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_NOCACHE)); |
182 | if (error) |
183 | goto fail1; |
184 | sg->sg_size = nbytes; |
185 | |
186 | /* |
187 | * Create a map for DMA transfers. |
188 | */ |
189 | /* XXX errno NetBSD->Linux */ |
190 | error = -bus_dmamap_create(sg->sg_tag, nbytes, nsegs, nbytes, 0, |
191 | BUS_DMA_NOWAIT, &sg->sg_map); |
192 | if (error) |
193 | goto fail2; |
194 | |
195 | /* |
196 | * Load the kva buffer into the map for DMA transfers. |
197 | */ |
198 | /* XXX errno NetBSD->Linux */ |
199 | error = -bus_dmamap_load(sg->sg_tag, sg->sg_map, sg->virtual, nbytes, |
200 | NULL, (BUS_DMA_NOWAIT | BUS_DMA_NOCACHE)); |
201 | if (error) |
202 | goto fail3; |
203 | |
204 | /* |
205 | * Use the kernel virtual address as the userland handle. |
206 | * |
207 | * XXX This leaks some information about kernel virtual |
208 | * addresses to userland; should we use an idr instead? |
209 | */ |
210 | sg->handle = (unsigned long)(uintptr_t)sg->virtual; |
211 | KASSERT(sg->virtual == (void *)(uintptr_t)sg->handle); |
212 | |
213 | /* Success! */ |
214 | *sgp = sg; |
215 | return 0; |
216 | |
217 | fail3: bus_dmamap_destroy(sg->sg_tag, sg->sg_map); |
218 | fail2: bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); |
219 | fail1: KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); |
220 | bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); |
221 | fail0: sg->sg_tag = NULL; /* XXX paranoia */ |
222 | kmem_free(sg, offsetof(struct drm_sg_mem, sg_segs[sg->sg_nsegs_max])); |
223 | return error; |
224 | } |
225 | |
226 | static void |
227 | drm_sg_free_mem(struct drm_device *dev, struct drm_sg_mem *sg) |
228 | { |
229 | |
230 | bus_dmamap_unload(sg->sg_tag, sg->sg_map); |
231 | bus_dmamap_destroy(sg->sg_tag, sg->sg_map); |
232 | bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); |
233 | KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); |
234 | bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); |
235 | sg->sg_tag = NULL; /* XXX paranoia */ |
236 | kmem_free(sg, offsetof(struct drm_sg_mem, sg_segs[sg->sg_nsegs_max])); |
237 | } |
238 | |