drm_scatter.c revision 1.1.2.3
1 /* $NetBSD: drm_scatter.c,v 1.1.2.3 2013/09/08 15:44:14 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 1.1.2.3 2013/09/08 15:44:14 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 47 int 48 drm_sg_alloc_ioctl(struct drm_device *dev, void *data, 49 struct drm_file *file __unused) 50 { 51 struct drm_scatter_gather *const request = data; 52 struct drm_sg_mem *sg; 53 int error; 54 55 /* 56 * XXX Should not hold this mutex during drm_sg_alloc. For 57 * now, we'll just use non-blocking allocations. 58 */ 59 KASSERT(mutex_is_locked(&drm_global_mutex)); 60 61 /* 62 * Sanity-check the inputs. 63 */ 64 if (!drm_core_check_feature(dev, DRIVER_SG)) 65 return -ENODEV; 66 if (dev->sg != NULL) 67 return -EBUSY; 68 if (request->size > 0xffffffffUL) 69 return -ENOMEM; 70 71 /* 72 * Do the allocation. 73 * 74 * XXX Would it be safe to drop drm_global_mutex here to avoid 75 * holding it during allocation? 76 */ 77 error = drm_sg_alloc_mem(dev, request->size, &sg); 78 if (error) 79 return error; 80 81 /* Set it up to be the device's scatter-gather memory. */ 82 dev->sg = sg; 83 84 /* Success! */ 85 request->handle = sg->handle; 86 return 0; 87 } 88 89 int 90 drm_sg_free(struct drm_device *dev, void *data, struct drm_file *file) 91 { 92 struct drm_scatter_gather *const request = data; 93 struct drm_sg_mem *sg; 94 95 KASSERT(mutex_is_locked(&drm_global_mutex)); 96 97 /* 98 * Sanity-check the inputs. 99 */ 100 if (!drm_core_check_feature(dev, DRIVER_SG)) 101 return -ENODEV; 102 103 sg = dev->sg; 104 if (sg == NULL) 105 return -ENXIO; 106 if (sg->handle != request->handle) 107 return -EINVAL; 108 109 /* Remove dev->sg. */ 110 dev->sg = NULL; 111 112 /* Success! */ 113 drm_sg_cleanup(sg); 114 return 0; 115 } 116 117 static int 118 drm_sg_alloc_mem(struct drm_device *dev, size_t size, struct drm_sg_mem **sgp) 119 { 120 int nsegs; 121 int error; 122 123 KASSERT(drm_core_check_feature(dev, DRIVER_SG)); 124 125 KASSERT(size <= (size_t)0xffffffffUL); /* XXX 32-bit sizes only? */ 126 const size_t nbytes = PAGE_ALIGN(size); 127 const size_t npages = nbytes >> PAGE_SHIFT; 128 KASSERT(npages <= (size_t)INT_MAX); 129 130 /* 131 * Allocate a drm_sg_mem record. 132 */ 133 struct drm_sg_mem *const sg = 134 kmem_zalloc(offsetof(struct drm_sg_mem, sg_segs[npages]), 135 KM_NOSLEEP); 136 if (sg == NULL) 137 return -ENOMEM; 138 sg->sg_tag = dev->dmat; 139 sg->sg_nsegs_max = (unsigned int)npages; 140 141 /* 142 * Allocate the requested amount of DMA-safe memory. 143 */ 144 KASSERT(sg->sg_nsegs_max <= (unsigned int)INT_MAX); 145 /* XXX errno NetBSD->Linux */ 146 error = -bus_dmamem_alloc(sg->sg_tag, nbytes, PAGE_SIZE, 0, 147 sg->sg_segs, (int)sg->sg_nsegs_max, &nsegs, BUS_DMA_NOWAIT); 148 if (error) 149 goto fail0; 150 KASSERT(0 <= nsegs); 151 sg->sg_nsegs = (unsigned int)nsegs; 152 153 /* 154 * XXX Old drm passed DRM_BUS_NOWAIT below but BUS_DMA_WAITOK 155 * above. WTF? 156 */ 157 158 /* 159 * Map the DMA-safe memory into kernel virtual address space. 160 */ 161 /* XXX errno NetBSD->Linux */ 162 error = -bus_dmamem_map(sg->sg_tag, sg->sg_segs, nsegs, nbytes, 163 &sg->virtual, 164 (BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_NOCACHE)); 165 if (error) 166 goto fail1; 167 sg->sg_size = nbytes; 168 169 /* 170 * Create a map for DMA transfers. 171 */ 172 /* XXX errno NetBSD->Linux */ 173 error = -bus_dmamap_create(sg->sg_tag, nbytes, nsegs, nbytes, 0, 174 BUS_DMA_NOWAIT, &sg->sg_map); 175 if (error) 176 goto fail2; 177 178 /* 179 * Load the kva buffer into the map for DMA transfers. 180 */ 181 /* XXX errno NetBSD->Linux */ 182 error = -bus_dmamap_load(sg->sg_tag, sg->sg_map, sg->virtual, nbytes, 183 NULL, (BUS_DMA_NOWAIT | BUS_DMA_NOCACHE)); 184 if (error) 185 goto fail3; 186 187 /* 188 * Use the kernel virtual address as the userland handle. 189 * 190 * XXX This leaks some information about kernel virtual 191 * addresses to userland; should we use an idr instead? 192 */ 193 sg->handle = (unsigned long)(uintptr_t)sg->virtual; 194 KASSERT(sg->virtual == (void *)(uintptr_t)sg->handle); 195 196 /* Success! */ 197 *sgp = sg; 198 return 0; 199 200 fail3: bus_dmamap_destroy(sg->sg_tag, sg->sg_map); 201 fail2: bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); 202 fail1: KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); 203 bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); 204 fail0: sg->sg_tag = NULL; /* XXX paranoia */ 205 kfree(sg); 206 return error; 207 } 208 209 void 210 drm_sg_cleanup(struct drm_sg_mem *sg) 211 { 212 213 bus_dmamap_unload(sg->sg_tag, sg->sg_map); 214 bus_dmamap_destroy(sg->sg_tag, sg->sg_map); 215 bus_dmamem_unmap(sg->sg_tag, sg->virtual, sg->sg_size); 216 KASSERT(sg->sg_nsegs <= (unsigned int)INT_MAX); 217 bus_dmamem_free(sg->sg_tag, sg->sg_segs, (int)sg->sg_nsegs); 218 sg->sg_tag = NULL; /* XXX paranoia */ 219 kmem_free(sg, offsetof(struct drm_sg_mem, sg_segs[sg->sg_nsegs_max])); 220 } 221
Indexes created Fri Oct 03 02:09:57 GMT 2025