drm_scatter.c revision 1.4
1 /* $NetBSD: drm_scatter.c,v 1.4 2018/02/07 06:18:46 mrg 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 1.4 2018/02/07 06:18:46 mrg 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 = NULL; 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
Indexes created Thu Oct 02 07:10:07 GMT 2025