drm_scatter.c revision 1.6
1 /* $NetBSD: drm_scatter.c,v 1.6 2021/12/19 00:28:20 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 1.6 2021/12/19 00:28:20 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 #include "../dist/drm/drm_internal.h" 45 #include "../dist/drm/drm_legacy.h" 46 47 static int drm_sg_alloc_mem(struct drm_device *, size_t, 48 struct drm_sg_mem **); 49 static void drm_sg_free_mem(struct drm_device *, struct drm_sg_mem *); 50 51 int 52 drm_legacy_sg_alloc(struct drm_device *dev, void *data, 53 struct drm_file *file __unused) 54 { 55 struct drm_scatter_gather *const request = data; 56 struct drm_sg_mem *sg = NULL; 57 int error; 58 59 /* 60 * XXX Should not hold this mutex during drm_sg_alloc. For 61 * now, we'll just use non-blocking allocations. 62 */ 63 KASSERT(mutex_is_locked(&drm_global_mutex)); 64 65 /* 66 * Sanity-check the inputs. 67 */ 68 if (!drm_core_check_feature(dev, DRIVER_SG)) 69 return -ENODEV; 70 if (dev->sg != NULL) 71 return -EBUSY; 72 if (request->size > 0xffffffffUL) 73 return -ENOMEM; 74 75 /* 76 * Do the allocation. 77 * 78 * XXX Would it be safe to drop drm_global_mutex here to avoid 79 * holding it during allocation? 80 */ 81 error = drm_sg_alloc_mem(dev, request->size, &sg); 82 if (error) 83 return error; 84 85 /* Set it up to be the device's scatter-gather memory. */ 86 dev->sg = sg; 87 88 /* Success! */ 89 request->handle = sg->handle; 90 return 0; 91 } 92 93 int 94 drm_legacy_sg_free(struct drm_device *dev, void *data, struct drm_file *file) 95 { 96 struct drm_scatter_gather *const request = data; 97 struct drm_sg_mem *sg; 98 99 KASSERT(mutex_is_locked(&drm_global_mutex)); 100 101 /* 102 * Sanity-check the inputs. 103 */ 104 if (!drm_core_check_feature(dev, DRIVER_SG)) 105 return -ENODEV; 106 107 sg = dev->sg; 108 if (sg == NULL) 109 return -ENXIO; 110 if (sg->handle != request->handle) 111 return -EINVAL; 112 113 /* Remove dev->sg. */ 114 dev->sg = NULL; 115 116 /* Free it. */ 117 drm_sg_free_mem(dev, sg); 118 119 /* Success! */ 120 return 0; 121 } 122 123 void 124 drm_legacy_sg_cleanup(struct drm_device *dev) 125 { 126 127 if (!drm_core_check_feature(dev, DRIVER_SG)) 128 return; 129 if (dev->sg == NULL) 130 return; 131 if (drm_core_check_feature(dev, DRIVER_MODESET)) 132 return; 133 134 drm_sg_free_mem(dev, dev->sg); 135 } 136 137 static int 138 drm_sg_alloc_mem(struct drm_device *dev, size_t size, struct drm_sg_mem **sgp) 139 { 140 int nsegs; 141 int error; 142 143 KASSERT(drm_core_check_feature(dev, DRIVER_SG)); 144 145 KASSERT(size <= (size_t)0xffffffffUL); /* XXX 32-bit sizes only? */ 146 const size_t nbytes = PAGE_ALIGN(size); 147 const size_t npages = nbytes >> PAGE_SHIFT; 148 KASSERT(npages <= (size_t)INT_MAX); 149 150 /* 151 * Allocate a drm_sg_mem record. 152 */ 153 struct drm_sg_mem *const sg = 154 kmem_zalloc(offsetof(struct drm_sg_mem, sg_segs[npages]), 155 KM_NOSLEEP); 156 if (sg == NULL) 157 return -ENOMEM; 158 sg->sg_tag = dev->dmat; 159 sg->sg_nsegs_max = (unsigned int)npages; 160 161 /* 162 * Allocate the requested amount of DMA-safe memory. 163 */ 164 KASSERT(sg->sg_nsegs_max <= (unsigned int)INT_MAX); 165 /* XXX errno NetBSD->Linux */ 166 error = -bus_dmamem_alloc(sg->sg_tag, nbytes, PAGE_SIZE, 0, 167 sg->sg_segs, (int)sg->sg_nsegs_max, &nsegs, BUS_DMA_NOWAIT); 168 if (error) 169 goto fail0; 170 KASSERT(0 <= nsegs); 171 sg->sg_nsegs = (unsigned int)nsegs; 172 173 /* 174 * XXX Old drm passed DRM_BUS_NOWAIT below but BUS_DMA_WAITOK 175 * above. WTF? 176 */ 177 178 /* 179 * Map the DMA-safe memory into kernel virtual address space. 180 */ 181 /* XXX errno NetBSD->Linux */ 182 error = -bus_dmamem_map(sg->sg_tag, sg->sg_segs, nsegs, nbytes, 183 &sg->virtual, 184 (BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_NOCACHE)); 185 if (error) 186 goto fail1; 187 sg->sg_size = nbytes; 188 189 /* 190 * Create a map for DMA transfers. 191 */ 192 /* XXX errno NetBSD->Linux */ 193 error = -bus_dmamap_create(sg->sg_tag, nbytes, nsegs, nbytes, 0, 194 BUS_DMA_NOWAIT, &sg->sg_map); 195 if (error) 196 goto fail2; 197 198 /* 199 * Load the kva buffer into the map for DMA transfers. 200 */ 201 /* XXX errno NetBSD->Linux */ 202 error = -bus_dmamap_load(sg->sg_tag, sg->sg_map, sg->virtual, nbytes, 203 NULL, (BUS_DMA_NOWAIT | BUS_DMA_NOCACHE)); 204 if (error) 205 goto fail3; 206 207 /* 208 * Use the kernel virtual address as the userland handle. 209 * 210 * XXX This leaks some information about kernel virtual 211 * addresses to userland; should we use an idr instead? 212 */ 213 sg->handle = (unsigned long)(uintptr_t)sg->virtual; 214 KASSERT(sg->virtual == (void *)(uintptr_t)sg->handle); 215 216 /* Success! */ 217 *sgp = sg; 218 return 0; 219 220 fail3: bus_dmamap_destroy(sg->sg_tag, sg->sg_map); 221 fail2: bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); 222 fail1: KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); 223 bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); 224 fail0: sg->sg_tag = NULL; /* XXX paranoia */ 225 kmem_free(sg, offsetof(struct drm_sg_mem, sg_segs[sg->sg_nsegs_max])); 226 return error; 227 } 228 229 static void 230 drm_sg_free_mem(struct drm_device *dev, struct drm_sg_mem *sg) 231 { 232 233 bus_dmamap_unload(sg->sg_tag, sg->sg_map); 234 bus_dmamap_destroy(sg->sg_tag, sg->sg_map); 235 bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); 236 KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); 237 bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); 238 sg->sg_tag = NULL; /* XXX paranoia */ 239 kmem_free(sg, offsetof(struct drm_sg_mem, sg_segs[sg->sg_nsegs_max])); 240 } 241
Indexes created Thu Oct 02 01:09:59 GMT 2025