linux_dma_buf.c revision 1.9
1 /* $NetBSD: linux_dma_buf.c,v 1.9 2021/12/19 10:19:53 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 1.9 2021/12/19 10:19:53 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/dma-resv.h> 45 46 struct dma_buf_file { 47 struct dma_buf *dbf_dmabuf; 48 }; 49 50 static int dmabuf_fop_poll(struct file *, int); 51 static int dmabuf_fop_close(struct file *); 52 static int dmabuf_fop_kqfilter(struct file *, struct knote *); 53 static int dmabuf_fop_mmap(struct file *, off_t *, size_t, int, int *, 54 int *, struct uvm_object **, int *); 55 56 static const struct fileops dmabuf_fileops = { 57 .fo_name = "dmabuf", 58 .fo_read = fbadop_read, 59 .fo_write = fbadop_write, 60 .fo_ioctl = fbadop_ioctl, 61 .fo_fcntl = fnullop_fcntl, 62 .fo_poll = dmabuf_fop_poll, 63 .fo_stat = fbadop_stat, 64 .fo_close = dmabuf_fop_close, 65 .fo_kqfilter = dmabuf_fop_kqfilter, 66 .fo_restart = fnullop_restart, 67 .fo_mmap = dmabuf_fop_mmap, 68 }; 69 70 struct dma_buf * 71 dma_buf_export(struct dma_buf_export_info *info) 72 { 73 struct dma_buf *dmabuf; 74 75 if (info->resv == NULL) { 76 dmabuf = kmem_zalloc(offsetof(struct dma_buf, db_resv_int[1]), 77 KM_SLEEP); 78 } else { 79 dmabuf = kmem_zalloc(sizeof(*dmabuf), KM_SLEEP); 80 } 81 82 dmabuf->priv = info->priv; 83 dmabuf->ops = info->ops; 84 dmabuf->size = info->size; 85 dmabuf->resv = info->resv; 86 87 mutex_init(&dmabuf->db_lock, MUTEX_DEFAULT, IPL_NONE); 88 dmabuf->db_refcnt = 1; 89 dma_resv_poll_init(&dmabuf->db_resv_poll); 90 91 if (dmabuf->resv == NULL) { 92 dmabuf->resv = &dmabuf->db_resv_int[0]; 93 dma_resv_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 ret = fd; 122 out0: return ret; 123 } 124 125 struct dma_buf * 126 dma_buf_get(int fd) 127 { 128 struct file *file; 129 struct dma_buf *dmabuf; 130 unsigned refcnt __diagused; 131 int error; 132 133 if ((file = fd_getfile(fd)) == NULL) { 134 error = EBADF; 135 goto fail0; 136 } 137 if (file->f_type != DTYPE_MISC || file->f_ops != &dmabuf_fileops) { 138 error = EINVAL; 139 goto fail1; 140 } 141 142 dmabuf = file->f_data; 143 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 144 KASSERT(refcnt > 1); 145 fd_putfile(fd); 146 return dmabuf; 147 148 fail1: fd_putfile(fd); 149 fail0: KASSERT(error); 150 return ERR_PTR(-error); 151 } 152 153 void 154 get_dma_buf(struct dma_buf *dmabuf) 155 { 156 unsigned refcnt __diagused; 157 158 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 159 KASSERT(refcnt > 1); 160 } 161 162 void 163 dma_buf_put(struct dma_buf *dmabuf) 164 { 165 166 if (atomic_dec_uint_nv(&dmabuf->db_refcnt) != 0) 167 return; 168 169 dma_resv_poll_fini(&dmabuf->db_resv_poll); 170 mutex_destroy(&dmabuf->db_lock); 171 if (dmabuf->resv == &dmabuf->db_resv_int[0]) { 172 dma_resv_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 attach->dev = dev; 188 189 mutex_enter(&dmabuf->db_lock); 190 if (dmabuf->ops->attach) 191 ret = dmabuf->ops->attach(dmabuf, attach); 192 mutex_exit(&dmabuf->db_lock); 193 if (ret) 194 goto fail0; 195 196 return attach; 197 198 fail0: kmem_free(attach, sizeof(*attach)); 199 return ERR_PTR(ret); 200 } 201 202 void 203 dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 204 { 205 206 mutex_enter(&dmabuf->db_lock); 207 if (dmabuf->ops->detach) 208 dmabuf->ops->detach(dmabuf, attach); 209 mutex_exit(&dmabuf->db_lock); 210 211 kmem_free(attach, sizeof(*attach)); 212 } 213 214 struct sg_table * 215 dma_buf_map_attachment(struct dma_buf_attachment *attach, 216 enum dma_data_direction dir) 217 { 218 219 return attach->dmabuf->ops->map_dma_buf(attach, dir); 220 } 221 222 void 223 dma_buf_unmap_attachment(struct dma_buf_attachment *attach, 224 struct sg_table *sg, enum dma_data_direction dir) 225 { 226 227 return attach->dmabuf->ops->unmap_dma_buf(attach, sg, dir); 228 } 229 230 static int 231 dmabuf_fop_close(struct file *file) 232 { 233 struct dma_buf_file *dbf = file->f_data; 234 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 235 236 dma_buf_put(dmabuf); 237 return 0; 238 } 239 240 static int 241 dmabuf_fop_poll(struct file *file, int events) 242 { 243 struct dma_buf_file *dbf = file->f_data; 244 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 245 struct dma_resv_poll *rpoll = &dmabuf->db_resv_poll; 246 247 return dma_resv_do_poll(dmabuf->resv, events, rpoll); 248 } 249 250 static int 251 dmabuf_fop_kqfilter(struct file *file, struct knote *kn) 252 { 253 struct dma_buf_file *dbf = file->f_data; 254 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 255 struct dma_resv_poll *rpoll = &dmabuf->db_resv_poll; 256 257 return dma_resv_kqfilter(dmabuf->resv, kn, rpoll); 258 } 259 260 static int 261 dmabuf_fop_mmap(struct file *file, off_t *offp, size_t size, int prot, 262 int *flagsp, int *advicep, struct uvm_object **uobjp, int *maxprotp) 263 { 264 struct dma_buf_file *dbf = file->f_data; 265 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 266 267 if (size > dmabuf->size) 268 return EINVAL; 269 270 return dmabuf->ops->mmap(dmabuf, offp, size, prot, flagsp, advicep, 271 uobjp, maxprotp); 272 } 273
Indexes created Fri Sep 26 08:10:20 GMT 2025