source: trunk/minix/drivers/libdriver/driver.c@ 20

Last change on this file since 20 was 9, checked in by Mattia Monga, 14 years ago

Minix 3.1.2a

File size: 12.0 KB
Line 
1/* This file contains device independent device driver interface.
2 *
3 * Changes:
4 * Jul 25, 2005 added SYS_SIG type for signals (Jorrit N. Herder)
5 * Sep 15, 2004 added SYN_ALARM type for timeouts (Jorrit N. Herder)
6 * Jul 23, 2004 removed kernel dependencies (Jorrit N. Herder)
7 * Apr 02, 1992 constructed from AT wini and floppy driver (Kees J. Bot)
8 *
9 *
10 * The drivers support the following operations (using message format m2):
11 *
12 * m_type DEVICE IO_ENDPT COUNT POSITION ADRRESS
13 * ----------------------------------------------------------------
14 * | DEV_OPEN | device | proc nr | | | |
15 * |------------+---------+---------+---------+---------+---------|
16 * | DEV_CLOSE | device | proc nr | | | |
17 * |------------+---------+---------+---------+---------+---------|
18 * | DEV_READ | device | proc nr | bytes | offset | buf ptr |
19 * |------------+---------+---------+---------+---------+---------|
20 * | DEV_WRITE | device | proc nr | bytes | offset | buf ptr |
21 * |------------+---------+---------+---------+---------+---------|
22 * | DEV_GATHER | device | proc nr | iov len | offset | iov ptr |
23 * |------------+---------+---------+---------+---------+---------|
24 * | DEV_SCATTER| device | proc nr | iov len | offset | iov ptr |
25 * |------------+---------+---------+---------+---------+---------|
26 * | DEV_IOCTL | device | proc nr |func code| | buf ptr |
27 * |------------+---------+---------+---------+---------+---------|
28 * | CANCEL | device | proc nr | r/w | | |
29 * |------------+---------+---------+---------+---------+---------|
30 * | HARD_STOP | | | | | |
31 * ----------------------------------------------------------------
32 *
33 * The file contains one entry point:
34 *
35 * driver_task: called by the device dependent task entry
36 */
37
38#include "../drivers.h"
39#include <sys/ioc_disk.h>
40#include "driver.h"
41
42#if (CHIP == INTEL)
43
44#if USE_EXTRA_DMA_BUF && DMA_BUF_SIZE < 2048
45/* A bit extra scratch for the Adaptec driver. */
46#define BUF_EXTRA (2048 - DMA_BUF_SIZE)
47#else
48#define BUF_EXTRA 0
49#endif
50
51/* Claim space for variables. */
52PRIVATE u8_t buffer[(unsigned) 2 * DMA_BUF_SIZE + BUF_EXTRA];
53u8_t *tmp_buf; /* the DMA buffer eventually */
54phys_bytes tmp_phys; /* phys address of DMA buffer */
55
56#else /* CHIP != INTEL */
57
58/* Claim space for variables. */
59u8_t tmp_buf[DMA_BUF_SIZE]; /* the DMA buffer */
60phys_bytes tmp_phys; /* phys address of DMA buffer */
61
62#endif /* CHIP != INTEL */
63
64FORWARD _PROTOTYPE( void init_buffer, (void) );
65FORWARD _PROTOTYPE( int do_rdwt, (struct driver *dr, message *mp) );
66FORWARD _PROTOTYPE( int do_vrdwt, (struct driver *dr, message *mp) );
67
68int device_caller;
69
70/*===========================================================================*
71 * driver_task *
72 *===========================================================================*/
73PUBLIC void driver_task(dp)
74struct driver *dp; /* Device dependent entry points. */
75{
76/* Main program of any device driver task. */
77
78 int r, proc_nr;
79 message mess;
80
81 /* Get a DMA buffer. */
82 init_buffer();
83
84 /* Here is the main loop of the disk task. It waits for a message, carries
85 * it out, and sends a reply.
86 */
87 while (TRUE) {
88
89 /* Wait for a request to read or write a disk block. */
90 if (receive(ANY, &mess) != OK) continue;
91
92 device_caller = mess.m_source;
93 proc_nr = mess.IO_ENDPT;
94
95 /* Now carry out the work. */
96 switch(mess.m_type) {
97 case DEV_OPEN: r = (*dp->dr_open)(dp, &mess); break;
98 case DEV_CLOSE: r = (*dp->dr_close)(dp, &mess); break;
99 case DEV_IOCTL: r = (*dp->dr_ioctl)(dp, &mess); break;
100 case CANCEL: r = (*dp->dr_cancel)(dp, &mess);break;
101 case DEV_SELECT: r = (*dp->dr_select)(dp, &mess);break;
102 case DEV_READ:
103 case DEV_WRITE: r = do_rdwt(dp, &mess); break;
104 case DEV_GATHER:
105 case DEV_SCATTER: r = do_vrdwt(dp, &mess); break;
106
107 case HARD_INT: /* leftover interrupt or expired timer. */
108 if(dp->dr_hw_int) {
109 (*dp->dr_hw_int)(dp, &mess);
110 }
111 continue;
112 case PROC_EVENT:
113 case SYS_SIG: (*dp->dr_signal)(dp, &mess);
114 continue; /* don't reply */
115 case SYN_ALARM: (*dp->dr_alarm)(dp, &mess);
116 continue; /* don't reply */
117 case DEV_PING: notify(mess.m_source);
118 continue;
119 default:
120 if(dp->dr_other)
121 r = (*dp->dr_other)(dp, &mess);
122 else
123 r = EINVAL;
124 break;
125 }
126
127 /* Clean up leftover state. */
128 (*dp->dr_cleanup)();
129
130 /* Finally, prepare and send the reply message. */
131 if (r != EDONTREPLY) {
132 mess.m_type = TASK_REPLY;
133 mess.REP_ENDPT = proc_nr;
134 /* Status is # of bytes transferred or error code. */
135 mess.REP_STATUS = r;
136 send(device_caller, &mess);
137 }
138 }
139}
140
141
142/*===========================================================================*
143 * init_buffer *
144 *===========================================================================*/
145PRIVATE void init_buffer()
146{
147/* Select a buffer that can safely be used for DMA transfers. It may also
148 * be used to read partition tables and such. Its absolute address is
149 * 'tmp_phys', the normal address is 'tmp_buf'.
150 */
151
152#if (CHIP == INTEL)
153 unsigned left;
154
155 tmp_buf = buffer;
156 sys_umap(SELF, D, (vir_bytes)buffer, (phys_bytes)sizeof(buffer), &tmp_phys);
157
158 if ((left = dma_bytes_left(tmp_phys)) < DMA_BUF_SIZE) {
159 /* First half of buffer crosses a 64K boundary, can't DMA into that */
160 tmp_buf += left;
161 tmp_phys += left;
162 }
163#endif /* CHIP == INTEL */
164}
165
166/*===========================================================================*
167 * do_rdwt *
168 *===========================================================================*/
169PRIVATE int do_rdwt(dp, mp)
170struct driver *dp; /* device dependent entry points */
171message *mp; /* pointer to read or write message */
172{
173/* Carry out a single read or write request. */
174 iovec_t iovec1;
175 int r, opcode;
176 phys_bytes phys_addr;
177
178 /* Disk address? Address and length of the user buffer? */
179 if (mp->COUNT < 0) return(EINVAL);
180
181 /* Check the user buffer. */
182 sys_umap(mp->IO_ENDPT, D, (vir_bytes) mp->ADDRESS, mp->COUNT, &phys_addr);
183 if (phys_addr == 0) return(EFAULT);
184
185 /* Prepare for I/O. */
186 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
187
188 /* Create a one element scatter/gather vector for the buffer. */
189 opcode = mp->m_type == DEV_READ ? DEV_GATHER : DEV_SCATTER;
190 iovec1.iov_addr = (vir_bytes) mp->ADDRESS;
191 iovec1.iov_size = mp->COUNT;
192
193 /* Transfer bytes from/to the device. */
194 r = (*dp->dr_transfer)(mp->IO_ENDPT, opcode, mp->POSITION, &iovec1, 1);
195
196 /* Return the number of bytes transferred or an error code. */
197 return(r == OK ? (mp->COUNT - iovec1.iov_size) : r);
198}
199
200/*==========================================================================*
201 * do_vrdwt *
202 *==========================================================================*/
203PRIVATE int do_vrdwt(dp, mp)
204struct driver *dp; /* device dependent entry points */
205message *mp; /* pointer to read or write message */
206{
207/* Carry out an device read or write to/from a vector of user addresses.
208 * The "user addresses" are assumed to be safe, i.e. FS transferring to/from
209 * its own buffers, so they are not checked.
210 */
211 static iovec_t iovec[NR_IOREQS];
212 iovec_t *iov;
213 phys_bytes iovec_size;
214 unsigned nr_req;
215 int r;
216
217 nr_req = mp->COUNT; /* Length of I/O vector */
218
219#if 0
220 if (mp->m_source < 0) {
221 /* Called by a task, no need to copy vector. */
222 iov = (iovec_t *) mp->ADDRESS;
223 } else
224#endif
225 {
226 /* Copy the vector from the caller to kernel space. */
227 if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
228 iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0]));
229
230 if (OK != sys_datacopy(mp->m_source, (vir_bytes) mp->ADDRESS,
231 SELF, (vir_bytes) iovec, iovec_size))
232 panic((*dp->dr_name)(),"bad I/O vector by", mp->m_source);
233 iov = iovec;
234 }
235
236 /* Prepare for I/O. */
237 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
238
239 /* Transfer bytes from/to the device. */
240 r = (*dp->dr_transfer)(mp->IO_ENDPT, mp->m_type, mp->POSITION, iov, nr_req);
241
242 /* Copy the I/O vector back to the caller. */
243#if 0
244 if (mp->m_source >= 0) {
245#endif
246 sys_datacopy(SELF, (vir_bytes) iovec,
247 mp->m_source, (vir_bytes) mp->ADDRESS, iovec_size);
248 return(r);
249}
250
251/*===========================================================================*
252 * no_name *
253 *===========================================================================*/
254PUBLIC char *no_name()
255{
256/* Use this default name if there is no specific name for the device. This was
257 * originally done by fetching the name from the task table for this process:
258 * "return(tasktab[proc_number(proc_ptr) + NR_TASKS].name);", but currently a
259 * real "noname" is returned. Perhaps, some system information service can be
260 * queried for a name at a later time.
261 */
262 static char name[] = "noname";
263 return name;
264}
265
266/*============================================================================*
267 * do_nop *
268 *============================================================================*/
269PUBLIC int do_nop(dp, mp)
270struct driver *dp;
271message *mp;
272{
273/* Nothing there, or nothing to do. */
274
275 switch (mp->m_type) {
276 case DEV_OPEN: return(ENODEV);
277 case DEV_CLOSE: return(OK);
278 case DEV_IOCTL: return(ENOTTY);
279 default: return(EIO);
280 }
281}
282
283/*============================================================================*
284 * nop_signal *
285 *============================================================================*/
286PUBLIC void nop_signal(dp, mp)
287struct driver *dp;
288message *mp;
289{
290/* Default action for signal is to ignore. */
291}
292
293/*============================================================================*
294 * nop_alarm *
295 *============================================================================*/
296PUBLIC void nop_alarm(dp, mp)
297struct driver *dp;
298message *mp;
299{
300/* Ignore the leftover alarm. */
301}
302
303/*===========================================================================*
304 * nop_prepare *
305 *===========================================================================*/
306PUBLIC struct device *nop_prepare(device)
307{
308/* Nothing to prepare for. */
309 return(NIL_DEV);
310}
311
312/*===========================================================================*
313 * nop_cleanup *
314 *===========================================================================*/
315PUBLIC void nop_cleanup()
316{
317/* Nothing to clean up. */
318}
319
320/*===========================================================================*
321 * nop_cancel *
322 *===========================================================================*/
323PUBLIC int nop_cancel(struct driver *dr, message *m)
324{
325/* Nothing to do for cancel. */
326 return(OK);
327}
328
329/*===========================================================================*
330 * nop_select *
331 *===========================================================================*/
332PUBLIC int nop_select(struct driver *dr, message *m)
333{
334/* Nothing to do for select. */
335 return(OK);
336}
337
338/*============================================================================*
339 * do_diocntl *
340 *============================================================================*/
341PUBLIC int do_diocntl(dp, mp)
342struct driver *dp;
343message *mp; /* pointer to ioctl request */
344{
345/* Carry out a partition setting/getting request. */
346 struct device *dv;
347 struct partition entry;
348 int s;
349
350 if (mp->REQUEST != DIOCSETP && mp->REQUEST != DIOCGETP) {
351 if(dp->dr_other) {
352 return dp->dr_other(dp, mp);
353 } else return(ENOTTY);
354 }
355
356 /* Decode the message parameters. */
357 if ((dv = (*dp->dr_prepare)(mp->DEVICE)) == NIL_DEV) return(ENXIO);
358
359 if (mp->REQUEST == DIOCSETP) {
360 /* Copy just this one partition table entry. */
361 if (OK != (s=sys_datacopy(mp->IO_ENDPT, (vir_bytes) mp->ADDRESS,
362 SELF, (vir_bytes) &entry, sizeof(entry))))
363 return s;
364 dv->dv_base = entry.base;
365 dv->dv_size = entry.size;
366 } else {
367 /* Return a partition table entry and the geometry of the drive. */
368 entry.base = dv->dv_base;
369 entry.size = dv->dv_size;
370 (*dp->dr_geometry)(&entry);
371 if (OK != (s=sys_datacopy(SELF, (vir_bytes) &entry,
372 mp->IO_ENDPT, (vir_bytes) mp->ADDRESS, sizeof(entry))))
373 return s;
374 }
375 return(OK);
376}
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