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1.1 root 1: #define _DDI_DKI 1
2: #define _SYSV4 1
3:
4: /*
5: * Routines for manipulating device numbers.
6: *
7: * System V defines "dev_t" as 32-bit, which makes some things problematic
8: * when attempting to run SVR4 drivers in an iBCS2 environment. The concept
9: * of external and internal numbers, introduced at the same time as the 32-
10: * bit "dev_t", provides an effective solution.
11: *
12: * This is of primary importance to clone devices which may want to support
13: * more than 256 connections, but any driver which wants or needs to encode
14: * more that 8 bits of information in the minor number may also benefit from
15: * use of the external/internal mapping regime.
16: */
17:
18: /*
19: *-IMPORTS:
20: * <sys/types.h>
21: * dev_t
22: * <limits.h>
23: * CHAR_BIT
24: */
25:
26: #include <sys/types.h>
27: #include <limits.h>
28:
29: /*
30: * Define this symbol to make the code in this module ignore the _max_minor,
31: * _major [], and _minor [] configuration tables, and simply map internal and
32: * external major and minor numbers one-to-one.
33: */
34: /* #define ONE_TO_ONE */
35:
36: /*
37: * If we are dealing with a situation where we are trying to run DDI/DKI code
38: * side-by-side with code that uses a different "dev_t", we rely on a layer
39: * that can may the pre-SVR4 or alien calling sequence for the DDI/DKI entry
40: * points. This code must deal with converting the old-style "dev_t" to a
41: * new-style "dev_t" and vice-versa.
42: *
43: * In particular, if a device generates a minor number outside the range of
44: * precision of the old-style system, the mapping layer must use these
45: * functions to select an appropriate major number to overflow to.
46: */
47:
48: #define DSHIFT (sizeof (dev_t) * CHAR_BIT / 2)
49:
50: #define GETEMAJOR(dev) ((major_t) ((dev) >> DSHIFT))
51: #define GETEMINOR(dev) ((minor_t) ((dev) & ~ (1L << DSHIFT)))
52: #define MAKEDEVICE(maj,min) (((dev_t) (maj) << DSHIFT) + (min))
53:
54:
55: /*
56: * The following external reference is to a table generated by the kernel
57: * configuration process for all the devices configured in the system. It
58: * defines a many-to-one mapping between external and internal major device
59: * numbers.
60: *
61: * This mapping can also affect internal device numbers; for instance,
62: * external major device 10, minor 5 might map to internal 2, minor 30.
63: */
64:
65: #ifndef ONE_TO_ONE
66:
67: extern major_t _maxmajor;
68: extern major_t _major []; /* internal major number for external major */
69: extern minor_t _minor []; /* value added to external minor number */
70:
71: #endif
72:
73: /*
74: *-STATUS:
75: * DDI/DKI
76: *
77: *-NAME:
78: * etoimajor Convert external to internal major device number.
79: *
80: *-SYNOPSIS:
81: * #include <sys/types.h>
82: * #include <sys/ddi.h>
83: *
84: * major_t etoimajor (major_t emaj);
85: *
86: *-ARGUMENTS:
87: * emaj External major number.
88: *
89: *-DESCRIPTION:
90: * etoimajor () converts the external major number (emaj) to an internal
91: * major number. See getemajor () for a description of external and
92: * internal major numbers.
93: *
94: *-RETURN VALUE:
95: * etoimajor () returns the internal major number or NODEV if the
96: * external major number is not valid.
97: *
98: *-LEVEL:
99: * Base or interrupt.
100: *
101: *-NOTES:
102: * Does not sleep.
103: *
104: * Driver-defined basic locks, read/write locks, and sleep locks may be
105: * held across calls to this function.
106: *
107: *-SEE ALSO:
108: * getemajor (), geteminor (), getmajor (), getminor (), itoemajor (),
109: * makedevice ().
110: */
111:
112: #if __USE_PROTO__
113: major_t (etoimajor) (major_t emaj)
114: #else
115: major_t
116: etoimajor __ARGS ((emaj))
117: major_t emaj;
118: #endif
119: {
120: #ifdef ONE_TO_ONE
121: return emaj;
122: #else
123: return (emaj >= _maxmajor ? NODEV : _major [emaj]);
124: #endif
125: }
126:
127:
128: /*
129: *-STATUS:
130: * DDI/DKI
131: *
132: *-NAME:
133: * getemajor Get external major device number.
134: *
135: *-SYNOPSIS:
136: * #include <sys/types.h>
137: * #include <sys/ddi.h>
138: *
139: * major_t getemajor (dev_t dev);
140: *
141: *-ARGUMENTS:
142: * dev External device number.
143: *
144: *-DESCRIPTION:
145: * getemajor () returns the external major number given a device number,
146: * "dev". External major numbers are visible to the user. Internal major
147: * numbers are only visible in the kernel. Since the range of major
148: * numbers may be large and sparsely populated, the kernel keeps a
149: * mapping between external and internal major numbers to save space.
150: *
151: * All driver entry points are passed device numbers using external
152: * major numbers.
153: *
154: * Usually, a driver with more than one external major number will have
155: * only one internal major number. However, some system implementations
156: * map one-to-one between internal and external major numbers. Here, the
157: * internal major number is the same as the external major number and the
158: * driver may have more than one internal major number.
159: *
160: *-RETURN VALUE:
161: * The external major number.
162: *
163: *-LEVEL:
164: * Base or interrupt.
165: *
166: *-NOTES:
167: * Does not sleep.
168: *
169: * Driver-defined basic locks, read/write locks, and sleep locks may be
170: * held across calls to this function.
171: *
172: *-SEE ALSO:
173: * etoimajor (), geteminor (), getmajor (), getminor (), makedevice ().
174: */
175:
176: #if __USE_PROTO__
177: major_t (getemajor) (n_dev_t dev)
178: #else
179: major_t
180: getemajor __ARGS ((dev))
181: n_dev_t dev;
182: #endif
183: {
184: return GETEMAJOR (dev);
185: }
186:
187:
188: /*
189: *-STATUS:
190: * DDI/DKI
191: *
192: *-NAME:
193: * geteminor Get external minor device number.
194: *
195: *-SYNOPSIS:
196: * #include <sys/types.h>
197: * #include <sys/ddi.h>
198: *
199: * minor_t geteminor (dev_t dev);
200: *
201: *-ARGUMENTS:
202: * dev External device number.
203: *
204: *-DESCRIPTION:
205: * geteminor () returns the external minor number given a device number,
206: * "dev". External minor numbers are visible to the user. Internal minor
207: * numbers are only visible in the kernel. Since a driver can support
208: * more than one external major device that maps to the same internal
209: * major device, the kernel keeps a mapping between external minor
210: * numbers and internal minor numbers to allow drivers to index arrays
211: * more easily. For example, a driver may support two devices, each with
212: * five minor numbers. The user may see each set of minor numbers
213: * numbered from zero to four, but the driver sees them as one set of
214: * minor numbers numbered zero to nine.
215: *
216: * All driver entry points are passed device numbers using external minor
217: * numbers.
218: *
219: * Systems that map external major numbers one-to-one with internal major
220: * numbers also map external minor numbers one-to-one with internal minor
221: * numbers.
222: *
223: *-RETURN VALUE:
224: * The external minor number.
225: *
226: *-LEVEL:
227: * Base or interrupt.
228: *
229: *-NOTES:
230: * Does not sleep.
231: *
232: * Driver-defined basic locks, read/write locks, and sleep locks may be
233: * held across calls to this function.
234: *
235: *-SEE ALSO:
236: * etoimajor (), getemajor (), getmajor (), getminor (), makedevice ()
237: */
238:
239: #if __USE_PROTO__
240: minor_t (geteminor) (n_dev_t dev)
241: #else
242: minor_t
243: geteminor __ARGS ((dev))
244: n_dev_t dev;
245: #endif
246: {
247: return GETEMINOR (dev);
248: }
249:
250:
251: /*
252: *-STATUS:
253: * DDI/DKI
254: *
255: *-NAME:
256: * getmajor Get internal major device number.
257: *
258: *-SYNOPSIS:
259: * #include <sys/types.h>
260: * #include <sys/ddi.h>
261: *
262: * major_t getemajor (dev_t dev);
263: *
264: *-ARGUMENTS:
265: * dev Device number.
266: *
267: *-DESCRIPTION:
268: * The getmajor () function extracts the internal major number from a
269: * device number. See getemajor () for an explanation of external and
270: * internal major numbers.
271: *
272: *-RETURN VALUE:
273: * The internal major number.
274: *
275: *-LEVEL:
276: * Base or interrupt.
277: *
278: *-NOTES:
279: * No validity checking is performed. If "dev" is invalid, an invalid
280: * number is returned.
281: *
282: * Does not sleep.
283: *
284: * Driver-defined basic locks, read/write locks, and sleep locks may be
285: * held across calls to this function.
286: *
287: *-SEE ALSO:
288: * etoimajor (), getemajor (), geteminor (), getminor (), makedevice ()
289: */
290:
291: #if __USE_PROTO__
292: major_t (getmajor) (n_dev_t dev)
293: #else
294: major_t
295: getmajor __ARGS ((dev))
296: n_dev_t dev;
297: #endif
298: {
299: #ifdef ONE_TO_ONE
300: return GETEMAJOR (dev);
301: #else
302: return _major [GETEMAJOR (dev)];
303: #endif
304: }
305:
306:
307: /*
308: *-STATUS:
309: * DDI/DKI
310: *
311: *-NAME:
312: * getminor Get internal minor device number.
313: *
314: *-SYNOPSIS:
315: * #include <sys/types.h>
316: * #include <sys/ddi.h>
317: *
318: * minor_t getminor (dev_t dev);
319: *
320: *-ARGUMENTS:
321: * dev Device number.
322: *
323: *-DESCRIPTION:
324: * The getminor () function extracts the internal minor number from a
325: * device number. See getemajor () for an explanation of external and
326: * internal major numbers.
327: *
328: *-RETURN VALUE:
329: * The internal minor number.
330: *
331: *-LEVEL:
332: * Base or interrupt.
333: *
334: *-NOTES:
335: * No validity checking is performed. If "dev" is invalid, an invalid
336: * number is returned.
337: *
338: * Does not sleep.
339: *
340: * Driver-defined basic locks, read/write locks, and sleep locks may be
341: * held across calls to this function.
342: *
343: *-SEE ALSO:
344: * etoimajor (), getemajor (), geteminor (), getmajor (), makedevice ()
345: */
346:
347: #if __USE_PROTO__
348: minor_t (getminor) (n_dev_t dev)
349: #else
350: minor_t
351: getminor __ARGS ((dev))
352: n_dev_t dev;
353: #endif
354: {
355: #ifdef ONE_TO_ONE
356: return GETEMINOR (dev);
357: #else
358: return GETEMINOR (dev) + _minor [GETEMAJOR (dev)];
359: #endif
360: }
361:
362:
363: /*
364: *-STATUS:
365: * DDI/DKI
366: *
367: *-NAME:
368: * itoemajor Convert internal to external major number.
369: *
370: *-SYNOPSIS:
371: * #include <sys/types.h>
372: * #include <sys/ddi.h>
373: *
374: * major_t itoemajor (major_t imaj, major_t prevemaj);
375: *
376: *-ARGUMENTS:
377: * imaj Internal major number.
378: *
379: * prevemaj Most recently obtained external major number (or
380: * NODEV, if this is the first time the function has been
381: * called).
382: *
383: *-DESCRIPTION:
384: * itoemajor () converts the internal major number to the external major
385: * number. The external-to-internal major number mapping can be many-to-
386: * one, and so any internal major number may correspond to more than one
387: * external major number. By repeatedly invoking this function, the
388: * driver can obtain all possible external major number values. See
389: * getemajor () for an explanation of external and internal major
390: * numbers.
391: *
392: *-RETURN VALUE:
393: * External major number, or NODEV if all have been searched.
394: *
395: *-LEVEL:
396: * Base or interrupt.
397: *
398: *-NOTES:
399: * Does not sleep.
400: *
401: * Driver-defined basic locks, read/write locks, and sleep locks may be
402: * held across calls to this function.
403: *
404: *-SEE ALSO:
405: * etoimajor (), getemajor (), geteminor (), getmajor (), getminor (),
406: * makedevice ()
407: */
408:
409: #if __USE_PROTO__
410: major_t (itoemajor) (major_t imaj, major_t prevemaj)
411: #else
412: major_t
413: itoemajor __ARGS ((imaj, prevemaj))
414: major_t imaj;
415: major_t prevemaj;
416: #endif
417: {
418: #ifdef ONE_TO_ONE
419: return prevemaj == NODEV ? imaj : NODEV;
420: #else
421: if (prevemaj == NODEV)
422: prevemaj = 0;
423: else
424: prevemaj ++;
425:
426: while (prevemaj ++ < _maxmajor)
427: if (_major [prevemaj] == imaj)
428: return prevemaj;
429:
430: return NODEV;
431: #endif
432: }
433:
434:
435: /*
436: *-STATUS:
437: * DDI/DKI
438: *
439: *-NAME:
440: * makedevice Make device number from major and minor numbers.
441: *
442: *-SYNOPSIS:
443: * #include <sys/types.h>
444: * #include <sys/ddi.h>
445: *
446: * dev_t makedevice (major_t majnum, minor_t minnum);
447: *
448: *-ARGUMENTS:
449: * majnum Major number.
450: *
451: * minnum Minor number.
452: *
453: *-DESCRIPTION:
454: * The makedevice () function creates a device number from a major and
455: * minor device number. makedevice () should be used to create device
456: * numbers so that the driver will port easily to releases that treat
457: * device numbers differently.
458: *
459: *-RETURN VALUE:
460: * The device number, containing both the major number and the minor
461: * number, is returned. No validation of the major or number numbers is
462: * performed.
463: *
464: *-LEVEL:
465: * Base or interrupt.
466: *
467: *-NOTES:
468: * Does not sleep.
469: *
470: * Driver-defined basic locks, read/write locks, and sleep locks may be
471: * held across calls to this function.
472: *
473: *-SEE ALSO:
474: * getemajor (), geteminor (), getmajor (), getminor ()
475: */
476:
477: #if __USE_PROTO__
478: n_dev_t (makedevice) (major_t majnum, minor_t minnum)
479: #else
480: n_dev_t
481: makedevice __ARGS ((majnum, minnum))
482: major_t majnum;
483: minor_t minnum;
484: #endif
485: {
486: return MAKEDEVICE (majnum, minnum);
487: }
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