Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="media-g-topology"> 2 <refmeta> 3 <refentrytitle>ioctl MEDIA_IOC_G_TOPOLOGY</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>MEDIA_IOC_G_TOPOLOGY</refname> 9 <refpurpose>Enumerate the graph topology and graph element properties</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct media_v2_topology *<parameter>argp</parameter></paramdef> 19 </funcprototype> 20 </funcsynopsis> 21 </refsynopsisdiv> 22 23 <refsect1> 24 <title>Arguments</title> 25 26 <variablelist> 27 <varlistentry> 28 <term><parameter>fd</parameter></term> 29 <listitem> 30 <para>File descriptor returned by 31 <link linkend='media-func-open'><function>open()</function></link>.</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>MEDIA_IOC_G_TOPOLOGY</para> 38 </listitem> 39 </varlistentry> 40 <varlistentry> 41 <term><parameter>argp</parameter></term> 42 <listitem> 43 <para></para> 44 </listitem> 45 </varlistentry> 46 </variablelist> 47 </refsect1> 48 49 <refsect1> 50 <title>Description</title> 51 <para>The typical usage of this ioctl is to call it twice. 52 On the first call, the structure defined at &media-v2-topology; should 53 be zeroed. At return, if no errors happen, this ioctl will return the 54 <constant>topology_version</constant> and the total number of entities, 55 interfaces, pads and links.</para> 56 <para>Before the second call, the userspace should allocate arrays to 57 store the graph elements that are desired, putting the pointers to them 58 at the ptr_entities, ptr_interfaces, ptr_links and/or ptr_pads, keeping 59 the other values untouched.</para> 60 <para>If the <constant>topology_version</constant> remains the same, the 61 ioctl should fill the desired arrays with the media graph elements.</para> 62 63 <table pgwide="1" frame="none" id="media-v2-topology"> 64 <title>struct <structname>media_v2_topology</structname></title> 65 <tgroup cols="5"> 66 <colspec colname="c1" /> 67 <colspec colname="c2" /> 68 <colspec colname="c3" /> 69 <colspec colname="c4" /> 70 <colspec colname="c5" /> 71 <tbody valign="top"> 72 <row> 73 <entry>__u64</entry> 74 <entry><structfield>topology_version</structfield></entry> 75 <entry></entry> 76 <entry></entry> 77 <entry>Version of the media graph topology. When the graph is 78 created, this field starts with zero. Every time a graph 79 element is added or removed, this field is 80 incremented.</entry> 81 </row> 82 <row> 83 <entry>__u64</entry> 84 <entry><structfield>num_entities</structfield></entry> 85 <entry></entry> 86 <entry></entry> 87 <entry>Number of entities in the graph</entry> 88 </row> 89 <row> 90 <entry>__u64</entry> 91 <entry><structfield>ptr_entities</structfield></entry> 92 <entry></entry> 93 <entry></entry> 94 <entry>A pointer to a memory area where the entities array 95 will be stored, converted to a 64-bits integer. 96 It can be zero. if zero, the ioctl won't store the 97 entities. It will just update 98 <constant>num_entities</constant></entry> 99 </row> 100 <row> 101 <entry>__u64</entry> 102 <entry><structfield>num_interfaces</structfield></entry> 103 <entry></entry> 104 <entry></entry> 105 <entry>Number of interfaces in the graph</entry> 106 </row> 107 <row> 108 <entry>__u64</entry> 109 <entry><structfield>ptr_interfaces</structfield></entry> 110 <entry></entry> 111 <entry></entry> 112 <entry>A pointer to a memory area where the interfaces array 113 will be stored, converted to a 64-bits integer. 114 It can be zero. if zero, the ioctl won't store the 115 interfaces. It will just update 116 <constant>num_interfaces</constant></entry> 117 </row> 118 <row> 119 <entry>__u64</entry> 120 <entry><structfield>num_pads</structfield></entry> 121 <entry></entry> 122 <entry></entry> 123 <entry>Total number of pads in the graph</entry> 124 </row> 125 <row> 126 <entry>__u64</entry> 127 <entry><structfield>ptr_pads</structfield></entry> 128 <entry></entry> 129 <entry></entry> 130 <entry>A pointer to a memory area where the pads array 131 will be stored, converted to a 64-bits integer. 132 It can be zero. if zero, the ioctl won't store the 133 pads. It will just update 134 <constant>num_pads</constant></entry> 135 </row> 136 <row> 137 <entry>__u64</entry> 138 <entry><structfield>num_links</structfield></entry> 139 <entry></entry> 140 <entry></entry> 141 <entry>Total number of data and interface links in the graph</entry> 142 </row> 143 <row> 144 <entry>__u64</entry> 145 <entry><structfield>ptr_links</structfield></entry> 146 <entry></entry> 147 <entry></entry> 148 <entry>A pointer to a memory area where the links array 149 will be stored, converted to a 64-bits integer. 150 It can be zero. if zero, the ioctl won't store the 151 links. It will just update 152 <constant>num_links</constant></entry> 153 </row> 154 </tbody> 155 </tgroup> 156 </table> 157 158 <table pgwide="1" frame="none" id="media-v2-entity"> 159 <title>struct <structname>media_v2_entity</structname></title> 160 <tgroup cols="5"> 161 <colspec colname="c1" /> 162 <colspec colname="c2" /> 163 <colspec colname="c3" /> 164 <colspec colname="c4" /> 165 <colspec colname="c5" /> 166 <tbody valign="top"> 167 <row> 168 <entry>__u32</entry> 169 <entry><structfield>id</structfield></entry> 170 <entry></entry> 171 <entry></entry> 172 <entry>Unique ID for the entity.</entry> 173 </row> 174 <row> 175 <entry>char</entry> 176 <entry><structfield>name</structfield>[64]</entry> 177 <entry></entry> 178 <entry></entry> 179 <entry>Entity name as an UTF-8 NULL-terminated string.</entry> 180 </row> 181 <row> 182 <entry>__u32</entry> 183 <entry><structfield>function</structfield></entry> 184 <entry></entry> 185 <entry></entry> 186 <entry>Entity main function, see <xref linkend="media-entity-type" /> for details.</entry> 187 </row> 188 <row> 189 <entry>__u32</entry> 190 <entry><structfield>reserved</structfield>[12]</entry> 191 <entry>Reserved for future extensions. Drivers and applications must 192 set this array to zero.</entry> 193 </row> 194 </tbody> 195 </tgroup> 196 </table> 197 198 <table pgwide="1" frame="none" id="media-v2-interface"> 199 <title>struct <structname>media_v2_interface</structname></title> 200 <tgroup cols="5"> 201 <colspec colname="c1" /> 202 <colspec colname="c2" /> 203 <colspec colname="c3" /> 204 <colspec colname="c4" /> 205 <colspec colname="c5" /> 206 <tbody valign="top"> 207 <row> 208 <entry>__u32</entry> 209 <entry><structfield>id</structfield></entry> 210 <entry></entry> 211 <entry></entry> 212 <entry>Unique ID for the interface.</entry> 213 </row> 214 <row> 215 <entry>__u32</entry> 216 <entry><structfield>intf_type</structfield></entry> 217 <entry></entry> 218 <entry></entry> 219 <entry>Interface type, see <xref linkend="media-intf-type" /> for details.</entry> 220 </row> 221 <row> 222 <entry>__u32</entry> 223 <entry><structfield>flags</structfield></entry> 224 <entry></entry> 225 <entry></entry> 226 <entry>Interface flags. Currently unused.</entry> 227 </row> 228 <row> 229 <entry>__u32</entry> 230 <entry><structfield>reserved</structfield>[9]</entry> 231 <entry></entry> 232 <entry></entry> 233 <entry>Reserved for future extensions. Drivers and applications must 234 set this array to zero.</entry> 235 </row> 236 <row> 237 <entry>struct media_v2_intf_devnode</entry> 238 <entry><structfield>devnode</structfield></entry> 239 <entry></entry> 240 <entry></entry> 241 <entry>Used only for device node interfaces. See <xref linkend="media-v2-intf-devnode" /> for details..</entry> 242 </row> 243 </tbody> 244 </tgroup> 245 </table> 246 247 <table pgwide="1" frame="none" id="media-v2-intf-devnode"> 248 <title>struct <structname>media_v2_interface</structname></title> 249 <tgroup cols="5"> 250 <colspec colname="c1" /> 251 <colspec colname="c2" /> 252 <colspec colname="c3" /> 253 <colspec colname="c4" /> 254 <colspec colname="c5" /> 255 <tbody valign="top"> 256 <row> 257 <entry>__u32</entry> 258 <entry><structfield>major</structfield></entry> 259 <entry></entry> 260 <entry></entry> 261 <entry>Device node major number.</entry> 262 </row> 263 <row> 264 <entry>__u32</entry> 265 <entry><structfield>minor</structfield></entry> 266 <entry></entry> 267 <entry></entry> 268 <entry>Device node minor number.</entry> 269 </row> 270 </tbody> 271 </tgroup> 272 </table> 273 274 <table pgwide="1" frame="none" id="media-v2-pad"> 275 <title>struct <structname>media_v2_pad</structname></title> 276 <tgroup cols="5"> 277 <colspec colname="c1" /> 278 <colspec colname="c2" /> 279 <colspec colname="c3" /> 280 <colspec colname="c4" /> 281 <colspec colname="c5" /> 282 <tbody valign="top"> 283 <row> 284 <entry>__u32</entry> 285 <entry><structfield>id</structfield></entry> 286 <entry></entry> 287 <entry></entry> 288 <entry>Unique ID for the pad.</entry> 289 </row> 290 <row> 291 <entry>__u32</entry> 292 <entry><structfield>entity_id</structfield></entry> 293 <entry></entry> 294 <entry></entry> 295 <entry>Unique ID for the entity where this pad belongs.</entry> 296 </row> 297 <row> 298 <entry>__u32</entry> 299 <entry><structfield>flags</structfield></entry> 300 <entry></entry> 301 <entry></entry> 302 <entry>Pad flags, see <xref linkend="media-pad-flag" /> for more details.</entry> 303 </row> 304 <row> 305 <entry>__u32</entry> 306 <entry><structfield>reserved</structfield>[9]</entry> 307 <entry></entry> 308 <entry></entry> 309 <entry>Reserved for future extensions. Drivers and applications must 310 set this array to zero.</entry> 311 </row> 312 </tbody> 313 </tgroup> 314 </table> 315 316 <table pgwide="1" frame="none" id="media-v2-link"> 317 <title>struct <structname>media_v2_pad</structname></title> 318 <tgroup cols="5"> 319 <colspec colname="c1" /> 320 <colspec colname="c2" /> 321 <colspec colname="c3" /> 322 <colspec colname="c4" /> 323 <colspec colname="c5" /> 324 <tbody valign="top"> 325 <row> 326 <entry>__u32</entry> 327 <entry><structfield>id</structfield></entry> 328 <entry></entry> 329 <entry></entry> 330 <entry>Unique ID for the pad.</entry> 331 </row> 332 <row> 333 <entry>__u32</entry> 334 <entry><structfield>source_id</structfield></entry> 335 <entry></entry> 336 <entry></entry> 337 <entry> 338 <para>On pad to pad links: unique ID for the source pad.</para> 339 <para>On interface to entity links: unique ID for the interface.</para> 340 </entry> 341 </row> 342 <row> 343 <entry>__u32</entry> 344 <entry><structfield>sink_id</structfield></entry> 345 <entry></entry> 346 <entry></entry> 347 <entry> 348 <para>On pad to pad links: unique ID for the sink pad.</para> 349 <para>On interface to entity links: unique ID for the entity.</para> 350 </entry> 351 </row> 352 <row> 353 <entry>__u32</entry> 354 <entry><structfield>flags</structfield></entry> 355 <entry></entry> 356 <entry></entry> 357 <entry>Link flags, see <xref linkend="media-link-flag" /> for more details.</entry> 358 </row> 359 <row> 360 <entry>__u32</entry> 361 <entry><structfield>reserved</structfield>[5]</entry> 362 <entry></entry> 363 <entry></entry> 364 <entry>Reserved for future extensions. Drivers and applications must 365 set this array to zero.</entry> 366 </row> 367 </tbody> 368 </tgroup> 369 </table> 370 371 </refsect1> 372 373 <refsect1> 374 &return-value; 375 376 <variablelist> 377 <varlistentry> 378 <term><errorcode>ENOSPC</errorcode></term> 379 <listitem> 380 <para>This is returned when either one or more of the num_entities, 381 num_interfaces, num_links or num_pads are non-zero and are smaller 382 than the actual number of elements inside the graph. This may happen 383 if the <constant>topology_version</constant> changed when compared 384 to the last time this ioctl was called. Userspace should usually 385 free the area for the pointers, zero the struct elements and call 386 this ioctl again.</para> 387 </listitem> 388 </varlistentry> 389 </variablelist> 390 </refsect1> 391 </refentry>
