1 /* $NetBSD: linux_dma_buf.c,v 1.1 2018/08/27 15:22:54 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 1.1 2018/08/27 15:22:54 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 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 fail1; 136 } 137 if (file->f_type != DTYPE_MISC || file->f_ops != &dmabuf_fileops) { 138 error = EINVAL; 139 goto fail0; 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 if (dmabuf->resv == &dmabuf->db_resv_int[0]) 170 reservation_object_fini(dmabuf->resv); 171 if (dmabuf->resv == &dmabuf->db_resv_int[0]) { 172 kmem_free(dmabuf, offsetof(struct dma_buf, db_resv_int[1])); 173 } else { 174 kmem_free(dmabuf, sizeof(*dmabuf)); 175 } 176 } 177 178 struct dma_buf_attachment * 179 dma_buf_attach(struct dma_buf *dmabuf, struct device *dev) 180 { 181 struct dma_buf_attachment *attach; 182 int ret = 0; 183 184 attach = kmem_zalloc(sizeof(*attach), KM_SLEEP); 185 attach->dmabuf = dmabuf; 186 187 mutex_enter(&dmabuf->db_lock); 188 if (dmabuf->ops->attach) 189 ret = dmabuf->ops->attach(dmabuf, dev, attach); 190 mutex_exit(&dmabuf->db_lock); 191 if (ret) 192 goto fail0; 193 194 return attach; 195 196 fail0: kmem_free(attach, sizeof(*attach)); 197 return ERR_PTR(ret); 198 } 199 200 void 201 dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 202 { 203 204 mutex_enter(&dmabuf->db_lock); 205 if (dmabuf->ops->detach) 206 dmabuf->ops->detach(dmabuf, attach); 207 mutex_exit(&dmabuf->db_lock); 208 209 kmem_free(attach, sizeof(*attach)); 210 } 211 212 struct sg_table * 213 dma_buf_map_attachment(struct dma_buf_attachment *attach, 214 enum dma_data_direction dir) 215 { 216 217 return attach->dmabuf->ops->map_dma_buf(attach, dir); 218 } 219 220 void 221 dma_buf_unmap_attachment(struct dma_buf_attachment *attach, 222 struct sg_table *sg, enum dma_data_direction dir) 223 { 224 225 return attach->dmabuf->ops->unmap_dma_buf(attach, sg, dir); 226 } 227 228 static int 229 dmabuf_fop_close(struct file *file) 230 { 231 struct dma_buf_file *dbf = file->f_data; 232 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 233 234 dma_buf_put(dmabuf); 235 return 0; 236 } 237 238 static int 239 dmabuf_fop_poll(struct file *file, int events) 240 { 241 #ifdef notyet 242 struct dma_buf_file *dbf = file->f_data; 243 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 244 245 return reservation_object_poll(dmabuf->resv, events); 246 #else 247 return -ENOSYS; 248 #endif 249 } 250 251 static int 252 dmabuf_fop_kqfilter(struct file *file, struct knote *knote) 253 { 254 #ifdef notyet 255 struct dma_buf_file *dbf = file->f_data; 256 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 257 258 return reservation_object_kqfilter(dmabuf->resv, knote); 259 #else 260 return -ENOSYS; 261 #endif 262 } 263 264 static int 265 dmabuf_fop_mmap(struct file *file, off_t *offp, size_t size, int prot, 266 int *flagsp, int *advicep, struct uvm_object **uobjp, int *maxprotp) 267 { 268 struct dma_buf_file *dbf = file->f_data; 269 struct dma_buf *dmabuf = dbf->dbf_dmabuf; 270 271 if (size > dmabuf->size) 272 return EINVAL; 273 274 return dmabuf->ops->mmap(dmabuf, offp, size, prot, flagsp, advicep, 275 uobjp, maxprotp); 276 } 277