1 /* $NetBSD: linux_dma_buf.c,v 1.4 2018/08/27 15:25:13 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 1.4 2018/08/27 15:25:13 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 reservation_poll_init(&dmabuf->db_resv_poll); 91 92 if (dmabuf->resv == NULL) { 93 dmabuf->resv = &dmabuf->db_resv_int[0]; 94 reservation_object_init(dmabuf->resv); 95 } 96 97 return dmabuf; 98 } 99 100 int 101 dma_buf_fd(struct dma_buf *dmabuf, int flags) 102 { 103 struct file *file; 104 int fd; 105 unsigned refcnt __diagused; 106 int ret; 107 108 ret = -fd_allocfile(&file, &fd); 109 if (ret) 110 goto out0; 111 112 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 113 KASSERT(refcnt > 1); 114 115 file->f_type = DTYPE_MISC; 116 file->f_flag = 0; /* XXX DRM code allows only O_CLOEXEC. */ 117 file->f_ops = &dmabuf_fileops; 118 file->f_data = dmabuf; 119 fd_set_exclose(curlwp, fd, (flags & O_CLOEXEC) != 0); 120 fd_affix(curproc, file, fd); 121 122 fd_putfile(fd); 123 ret = fd; 124 out0: return ret; 125 } 126 127 struct dma_buf * 128 dma_buf_get(int fd) 129 { 130 struct file *file; 131 struct dma_buf *dmabuf; 132 unsigned refcnt __diagused; 133 int error; 134 135 if ((file = fd_getfile(fd)) == NULL) { 136 error = EBADF; 137 goto fail1; 138 } 139 if (file->f_type != DTYPE_MISC || file->f_ops != &dmabuf_fileops) { 140 error = EINVAL; 141 goto fail0; 142 } 143 144 dmabuf = file->f_data; 145 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 146 KASSERT(refcnt > 1); 147 fd_putfile(fd); 148 return dmabuf; 149 150 fail1: fd_putfile(fd); 151 fail0: KASSERT(error); 152 return ERR_PTR(-error); 153 } 154 155 void 156 get_dma_buf(struct dma_buf *dmabuf) 157 { 158 unsigned refcnt __diagused; 159 160 refcnt = atomic_inc_uint_nv(&dmabuf->db_refcnt); 161 KASSERT(refcnt > 1); 162 } 163 164 void 165 dma_buf_put(struct dma_buf *dmabuf) 166 { 167 168 if (atomic_dec_uint_nv(&dmabuf->db_refcnt) != 0) 169 return; 170 171 reservation_poll_fini(&dmabuf->db_resv_poll); 172 mutex_destroy(&dmabuf->db_lock); 173 if (dmabuf->resv == &dmabuf->db_resv_int[0]) { 174 reservation_object_fini(dmabuf->resv); 175 kmem_free(dmabuf, offsetof(struct dma_buf, db_resv_int[1])); 176 } else { 177 kmem_free(dmabuf, sizeof(*dmabuf)); 178 } 179 } 180 181 struct dma_buf_attachment * 182 dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) 183 { 184 struct dma_buf_attachment *attach; 185 int ret = 0; 186 187 attach = kmem_zalloc(sizeof(*attach), KM_SLEEP); 188 attach->dmabuf = dmabuf; 189 190 mutex_enter(&dmabuf->db_lock); 191 if (dmabuf->ops->attach) 192 ret = dmabuf->ops->attach(dmabuf, dev, attach); 193 mutex_exit(&dmabuf->db_lock); 194 if (ret) 195 goto fail0; 196 197 return attach; 198 199 fail0: kmem_free(attach, sizeof(*attach)); 200 return ERR_PTR(ret); 201 } 202 203 void 204 dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 205 { 206 207 mutex_enter(&dmabuf->db_lock); 208 if (dmabuf->ops->detach) 209 dmabuf->ops->detach(dmabuf, attach); 210 mutex_exit(&dmabuf->db_lock); 211 212 kmem_free(attach, sizeof(*attach)); 213 } 214 215 struct sg_table * 216 dma_buf_map_attachment(struct dma_buf_attachment *attach, 217 enum dma_data_direction dir) 218 { 219 220 return attach->dmabuf->ops->map_dma_buf(attach, dir); 221 } 222 223 void 224 dma_buf_unmap_attachment(struct dma_buf_attachment *attach, 225 struct sg_table *sg, enum dma_data_direction dir) 226 { 227 228 return attach->dmabuf->ops->unmap_dma_buf(attach, sg, dir); 229 } 230 231 static int 232 dmabuf_fop_close(struct file *file) 233 { 234 struct dma_buf_file *dbf = file->f_data; 235 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 236 237 dma_buf_put(dmabuf); 238 return 0; 239 } 240 241 static int 242 dmabuf_fop_poll(struct file *file, int events) 243 { 244 struct dma_buf_file *dbf = file->f_data; 245 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 246 struct reservation_poll *rpoll = &dmabuf->db_resv_poll; 247 248 return reservation_object_poll(dmabuf->resv, events, rpoll); 249 } 250 251 static int 252 dmabuf_fop_kqfilter(struct file *file, struct knote *kn) 253 { 254 struct dma_buf_file *dbf = file->f_data; 255 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 256 struct reservation_poll *rpoll = &dmabuf->db_resv_poll; 257 258 return reservation_object_kqfilter(dmabuf->resv, kn, rpoll); 259 } 260 261 static int 262 dmabuf_fop_mmap(struct file *file, off_t *offp, size_t size, int prot, 263 int *flagsp, int *advicep, struct uvm_object **uobjp, int *maxprotp) 264 { 265 struct dma_buf_file *dbf = file->f_data; 266 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 267 268 if (size > dmabuf->size) 269 return EINVAL; 270 271 return dmabuf->ops->mmap(dmabuf, offp, size, prot, flagsp, advicep, 272 uobjp, maxprotp); 273 } 274