linux_dma_buf.c revision 1.3
1 /* $NetBSD: linux_dma_buf.c,v 1.3 2018/08/27 15:24:40 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2018 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: linux_dma_buf.c,v 1.3 2018/08/27 15:24:40 riastradh Exp $"); 34 35 #include <sys/types.h> 36 #include <sys/atomic.h> 37 #include <sys/file.h> 38 #include <sys/filedesc.h> 39 #include <sys/kmem.h> 40 #include <sys/mutex.h> 41 42 #include <linux/dma-buf.h> 43 #include <linux/err.h> 44 #include <linux/fence.h> 45 #include <linux/reservation.h> 46 47 struct dma_buf_file { 48 struct dma_buf *dbf_dmabuf; 49 }; 50 51 static int dmabuf_fop_poll(struct file *, int); 52 static int dmabuf_fop_close(struct file *); 53 static int dmabuf_fop_kqfilter(struct file *, struct knote *); 54 static int dmabuf_fop_mmap(struct file *, off_t *, size_t, int, int *, 55 int *, struct uvm_object **, int *); 56 57 static const struct fileops dmabuf_fileops = { 58 .fo_name = "dmabuf", 59 .fo_read = fbadop_read, 60 .fo_write = fbadop_write, 61 .fo_ioctl = fbadop_ioctl, 62 .fo_fcntl = fnullop_fcntl, 63 .fo_poll = dmabuf_fop_poll, 64 .fo_stat = fbadop_stat, 65 .fo_close = dmabuf_fop_close, 66 .fo_kqfilter = dmabuf_fop_kqfilter, 67 .fo_restart = fnullop_restart, 68 .fo_mmap = dmabuf_fop_mmap, 69 }; 70 71 struct dma_buf * 72 dma_buf_export(struct dma_buf_export_info *info) 73 { 74 struct dma_buf *dmabuf; 75 76 if (info->resv == NULL) { 77 dmabuf = kmem_zalloc(offsetof(struct dma_buf, db_resv_int[1]), 78 KM_SLEEP); 79 } else { 80 dmabuf = kmem_zalloc(sizeof(*dmabuf), KM_SLEEP); 81 } 82 83 dmabuf->priv = info->priv; 84 dmabuf->ops = info->ops; 85 dmabuf->size = info->size; 86 dmabuf->resv = info->resv; 87 88 mutex_init(&dmabuf->db_lock, MUTEX_DEFAULT, IPL_NONE); 89 dmabuf->db_refcnt = 1; 90 91 if (dmabuf->resv == NULL) { 92 dmabuf->resv = &dmabuf->db_resv_int[0]; 93 reservation_object_init(dmabuf->resv); 94 } 95 96 return dmabuf; 97 } 98 99 int 100 dma_buf_fd(struct dma_buf *dmabuf, int flags) 101 { 102 struct file *file; 103 int fd; 104 unsigned refcnt __diagused; 105 int ret; 106 107 ret = -fd_allocfile(&file, &fd); 108 if (ret) 109 goto out0; 110 111 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 112 KASSERT(refcnt > 1); 113 114 file->f_type = DTYPE_MISC; 115 file->f_flag = 0; /* XXX DRM code allows only O_CLOEXEC. */ 116 file->f_ops = &dmabuf_fileops; 117 file->f_data = dmabuf; 118 fd_set_exclose(curlwp, fd, (flags & O_CLOEXEC) != 0); 119 fd_affix(curproc, file, fd); 120 121 fd_putfile(fd); 122 ret = fd; 123 out0: return ret; 124 } 125 126 struct dma_buf * 127 dma_buf_get(int fd) 128 { 129 struct file *file; 130 struct dma_buf *dmabuf; 131 unsigned refcnt __diagused; 132 int error; 133 134 if ((file = fd_getfile(fd)) == NULL) { 135 error = EBADF; 136 goto fail1; 137 } 138 if (file->f_type != DTYPE_MISC || file->f_ops != &dmabuf_fileops) { 139 error = EINVAL; 140 goto fail0; 141 } 142 143 dmabuf = file->f_data; 144 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 145 KASSERT(refcnt > 1); 146 fd_putfile(fd); 147 return dmabuf; 148 149 fail1: fd_putfile(fd); 150 fail0: KASSERT(error); 151 return ERR_PTR(-error); 152 } 153 154 void 155 get_dma_buf(struct dma_buf *dmabuf) 156 { 157 unsigned refcnt __diagused; 158 159 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 160 KASSERT(refcnt > 1); 161 } 162 163 void 164 dma_buf_put(struct dma_buf *dmabuf) 165 { 166 167 if (atomic_dec_uint_nv(&dmabuf->db_refcnt) != 0) 168 return; 169 170 mutex_destroy(&dmabuf->db_lock); 171 if (dmabuf->resv == &dmabuf->db_resv_int[0]) { 172 reservation_object_fini(dmabuf->resv); 173 kmem_free(dmabuf, offsetof(struct dma_buf, db_resv_int[1])); 174 } else { 175 kmem_free(dmabuf, sizeof(*dmabuf)); 176 } 177 } 178 179 struct dma_buf_attachment * 180 dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) 181 { 182 struct dma_buf_attachment *attach; 183 int ret = 0; 184 185 attach = kmem_zalloc(sizeof(*attach), KM_SLEEP); 186 attach->dmabuf = dmabuf; 187 188 mutex_enter(&dmabuf->db_lock); 189 if (dmabuf->ops->attach) 190 ret = dmabuf->ops->attach(dmabuf, dev, attach); 191 mutex_exit(&dmabuf->db_lock); 192 if (ret) 193 goto fail0; 194 195 return attach; 196 197 fail0: kmem_free(attach, sizeof(*attach)); 198 return ERR_PTR(ret); 199 } 200 201 void 202 dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 203 { 204 205 mutex_enter(&dmabuf->db_lock); 206 if (dmabuf->ops->detach) 207 dmabuf->ops->detach(dmabuf, attach); 208 mutex_exit(&dmabuf->db_lock); 209 210 kmem_free(attach, sizeof(*attach)); 211 } 212 213 struct sg_table * 214 dma_buf_map_attachment(struct dma_buf_attachment *attach, 215 enum dma_data_direction dir) 216 { 217 218 return attach->dmabuf->ops->map_dma_buf(attach, dir); 219 } 220 221 void 222 dma_buf_unmap_attachment(struct dma_buf_attachment *attach, 223 struct sg_table *sg, enum dma_data_direction dir) 224 { 225 226 return attach->dmabuf->ops->unmap_dma_buf(attach, sg, dir); 227 } 228 229 static int 230 dmabuf_fop_close(struct file *file) 231 { 232 struct dma_buf_file *dbf = file->f_data; 233 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 234 235 dma_buf_put(dmabuf); 236 return 0; 237 } 238 239 static int 240 dmabuf_fop_poll(struct file *file, int events) 241 { 242 #ifdef notyet 243 struct dma_buf_file *dbf = file->f_data; 244 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 245 246 return reservation_object_poll(dmabuf->resv, events); 247 #else 248 return -ENOSYS; 249 #endif 250 } 251 252 static int 253 dmabuf_fop_kqfilter(struct file *file, struct knote *knote) 254 { 255 #ifdef notyet 256 struct dma_buf_file *dbf = file->f_data; 257 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 258 259 return reservation_object_kqfilter(dmabuf->resv, knote); 260 #else 261 return -ENOSYS; 262 #endif 263 } 264 265 static int 266 dmabuf_fop_mmap(struct file *file, off_t *offp, size_t size, int prot, 267 int *flagsp, int *advicep, struct uvm_object **uobjp, int *maxprotp) 268 { 269 struct dma_buf_file *dbf = file->f_data; 270 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 271 272 if (size > dmabuf->size) 273 return EINVAL; 274 275 return dmabuf->ops->mmap(dmabuf, offp, size, prot, flagsp, advicep, 276 uobjp, maxprotp); 277 } 278
Indexes created Fri Sep 26 08:10:20 GMT 2025