source: branches/minix3-book/drivers/libdriver/driver.c@ 20

Last change on this file since 20 was 4, checked in by Mattia Monga, 14 years ago

Importazione sorgenti libro
File size: 11.5 KB
RevLine 
[4]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 PROC_NR 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#define BUF_EXTRA 0
43
44/* Claim space for variables. */
45PRIVATE u8_t buffer[(unsigned) 2 * DMA_BUF_SIZE + BUF_EXTRA];
46u8_t *tmp_buf; /* the DMA buffer eventually */
47phys_bytes tmp_phys; /* phys address of DMA buffer */
48
49FORWARD _PROTOTYPE( void init_buffer, (void) );
50FORWARD _PROTOTYPE( int do_rdwt, (struct driver *dr, message *mp) );
51FORWARD _PROTOTYPE( int do_vrdwt, (struct driver *dr, message *mp) );
52
53int device_caller;
54
55/*===========================================================================*
56 * driver_task *
57 *===========================================================================*/
58PUBLIC void driver_task(dp)
59struct driver *dp; /* Device dependent entry points. */
60{
61/* Main program of any device driver task. */
62
63 int r, proc_nr;
64 message mess;
65
66 /* Get a DMA buffer. */
67 init_buffer();
68
69 /* Here is the main loop of the disk task. It waits for a message, carries
70 * it out, and sends a reply.
71 */
72 while (TRUE) {
73
74 /* Wait for a request to read or write a disk block. */
75 if(receive(ANY, &mess) != OK) continue;
76
77 device_caller = mess.m_source;
78 proc_nr = mess.PROC_NR;
79
80 /* Now carry out the work. */
81 switch(mess.m_type) {
82 case DEV_OPEN: r = (*dp->dr_open)(dp, &mess); break;
83 case DEV_CLOSE: r = (*dp->dr_close)(dp, &mess); break;
84 case DEV_IOCTL: r = (*dp->dr_ioctl)(dp, &mess); break;
85 case CANCEL: r = (*dp->dr_cancel)(dp, &mess);break;
86 case DEV_SELECT: r = (*dp->dr_select)(dp, &mess);break;
87
88 case DEV_READ:
89 case DEV_WRITE: r = do_rdwt(dp, &mess); break;
90 case DEV_GATHER:
91 case DEV_SCATTER: r = do_vrdwt(dp, &mess); break;
92
93 case HARD_INT: /* leftover interrupt or expired timer. */
94 if(dp->dr_hw_int) {
95 (*dp->dr_hw_int)(dp, &mess);
96 }
97 continue;
98 case SYS_SIG: (*dp->dr_signal)(dp, &mess);
99 continue; /* don't reply */
100 case SYN_ALARM: (*dp->dr_alarm)(dp, &mess);
101 continue; /* don't reply */
102 default:
103 if(dp->dr_other)
104 r = (*dp->dr_other)(dp, &mess);
105 else
106 r = EINVAL;
107 break;
108 }
109
110 /* Clean up leftover state. */
111 (*dp->dr_cleanup)();
112
113 /* Finally, prepare and send the reply message. */
114 if (r != EDONTREPLY) {
115 mess.m_type = TASK_REPLY;
116 mess.REP_PROC_NR = proc_nr;
117 /* Status is # of bytes transferred or error code. */
118 mess.REP_STATUS = r;
119 send(device_caller, &mess);
120 }
121 }
122}
123
124/*===========================================================================*
125 * init_buffer *
126 *===========================================================================*/
127PRIVATE void init_buffer()
128{
129/* Select a buffer that can safely be used for DMA transfers. It may also
130 * be used to read partition tables and such. Its absolute address is
131 * 'tmp_phys', the normal address is 'tmp_buf'.
132 */
133
134 unsigned left;
135
136 tmp_buf = buffer;
137 sys_umap(SELF, D, (vir_bytes)buffer, (phys_bytes)sizeof(buffer), &tmp_phys);
138
139 if ((left = dma_bytes_left(tmp_phys)) < DMA_BUF_SIZE) {
140 /* First half of buffer crosses a 64K boundary, can't DMA into that */
141 tmp_buf += left;
142 tmp_phys += left;
143 }
144}
145
146/*===========================================================================*
147 * do_rdwt *
148 *===========================================================================*/
149PRIVATE int do_rdwt(dp, mp)
150struct driver *dp; /* device dependent entry points */
151message *mp; /* pointer to read or write message */
152{
153/* Carry out a single read or write request. */
154 iovec_t iovec1;
155 int r, opcode;
156 phys_bytes phys_addr;
157
158 /* Disk address? Address and length of the user buffer? */
159 if (mp->COUNT < 0) return(EINVAL);
160
161 /* Check the user buffer. */
162 sys_umap(mp->PROC_NR, D, (vir_bytes) mp->ADDRESS, mp->COUNT, &phys_addr);
163 if (phys_addr == 0) return(EFAULT);
164
165 /* Prepare for I/O. */
166 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
167
168 /* Create a one element scatter/gather vector for the buffer. */
169 opcode = mp->m_type == DEV_READ ? DEV_GATHER : DEV_SCATTER;
170 iovec1.iov_addr = (vir_bytes) mp->ADDRESS;
171 iovec1.iov_size = mp->COUNT;
172
173 /* Transfer bytes from/to the device. */
174 r = (*dp->dr_transfer)(mp->PROC_NR, opcode, mp->POSITION, &iovec1, 1);
175
176 /* Return the number of bytes transferred or an error code. */
177 return(r == OK ? (mp->COUNT - iovec1.iov_size) : r);
178}
179
180/*==========================================================================*
181 * do_vrdwt *
182 *==========================================================================*/
183PRIVATE int do_vrdwt(dp, mp)
184struct driver *dp; /* device dependent entry points */
185message *mp; /* pointer to read or write message */
186{
187/* Carry out an device read or write to/from a vector of user addresses.
188 * The "user addresses" are assumed to be safe, i.e. FS transferring to/from
189 * its own buffers, so they are not checked.
190 */
191 static iovec_t iovec[NR_IOREQS];
192 iovec_t *iov;
193 phys_bytes iovec_size;
194 unsigned nr_req;
195 int r;
196
197 nr_req = mp->COUNT; /* Length of I/O vector */
198
199 if (mp->m_source < 0) {
200 /* Called by a task, no need to copy vector. */
201 iov = (iovec_t *) mp->ADDRESS;
202 } else {
203 /* Copy the vector from the caller to kernel space. */
204 if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
205 iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0]));
206
207 if (OK != sys_datacopy(mp->m_source, (vir_bytes) mp->ADDRESS,
208 SELF, (vir_bytes) iovec, iovec_size))
209 panic((*dp->dr_name)(),"bad I/O vector by", mp->m_source);
210 iov = iovec;
211 }
212
213 /* Prepare for I/O. */
214 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO);
215
216 /* Transfer bytes from/to the device. */
217 r = (*dp->dr_transfer)(mp->PROC_NR, mp->m_type, mp->POSITION, iov, nr_req);
218
219 /* Copy the I/O vector back to the caller. */
220 if (mp->m_source >= 0) {
221 sys_datacopy(SELF, (vir_bytes) iovec,
222 mp->m_source, (vir_bytes) mp->ADDRESS, iovec_size);
223 }
224 return(r);
225}
226
227/*===========================================================================*
228 * no_name *
229 *===========================================================================*/
230PUBLIC char *no_name()
231{
232/* Use this default name if there is no specific name for the device. This was
233 * originally done by fetching the name from the task table for this process:
234 * "return(tasktab[proc_number(proc_ptr) + NR_TASKS].name);", but currently a
235 * real "noname" is returned. Perhaps, some system information service can be
236 * queried for a name at a later time.
237 */
238 static char name[] = "noname";
239 return name;
240}
241
242/*============================================================================*
243 * do_nop *
244 *============================================================================*/
245PUBLIC int do_nop(dp, mp)
246struct driver *dp;
247message *mp;
248{
249/* Nothing there, or nothing to do. */
250
251 switch (mp->m_type) {
252 case DEV_OPEN: return(ENODEV);
253 case DEV_CLOSE: return(OK);
254 case DEV_IOCTL: return(ENOTTY);
255 default: return(EIO);
256 }
257}
258
259/*============================================================================*
260 * nop_signal *
261 *============================================================================*/
262PUBLIC void nop_signal(dp, mp)
263struct driver *dp;
264message *mp;
265{
266/* Default action for signal is to ignore. */
267}
268
269/*============================================================================*
270 * nop_alarm *
271 *============================================================================*/
272PUBLIC void nop_alarm(dp, mp)
273struct driver *dp;
274message *mp;
275{
276/* Ignore the leftover alarm. */
277}
278
279/*===========================================================================*
280 * nop_prepare *
281 *===========================================================================*/
282PUBLIC struct device *nop_prepare(device)
283{
284/* Nothing to prepare for. */
285 return(NIL_DEV);
286}
287
288/*===========================================================================*
289 * nop_cleanup *
290 *===========================================================================*/
291PUBLIC void nop_cleanup()
292{
293/* Nothing to clean up. */
294}
295
296/*===========================================================================*
297 * nop_cancel *
298 *===========================================================================*/
299PUBLIC int nop_cancel(struct driver *dr, message *m)
300{
301/* Nothing to do for cancel. */
302 return(OK);
303}
304
305/*===========================================================================*
306 * nop_select *
307 *===========================================================================*/
308PUBLIC int nop_select(struct driver *dr, message *m)
309{
310/* Nothing to do for select. */
311 return(OK);
312}
313
314/*============================================================================*
315 * do_diocntl *
316 *============================================================================*/
317PUBLIC int do_diocntl(dp, mp)
318struct driver *dp;
319message *mp; /* pointer to ioctl request */
320{
321/* Carry out a partition setting/getting request. */
322 struct device *dv;
323 struct partition entry;
324 int s;
325
326 if (mp->REQUEST != DIOCSETP && mp->REQUEST != DIOCGETP) {
327 if(dp->dr_other) {
328 return dp->dr_other(dp, mp);
329 } else return(ENOTTY);
330 }
331
332 /* Decode the message parameters. */
333 if ((dv = (*dp->dr_prepare)(mp->DEVICE)) == NIL_DEV) return(ENXIO);
334
335 if (mp->REQUEST == DIOCSETP) {
336 /* Copy just this one partition table entry. */
337 if (OK != (s=sys_datacopy(mp->PROC_NR, (vir_bytes) mp->ADDRESS,
338 SELF, (vir_bytes) &entry, sizeof(entry))))
339 return s;
340 dv->dv_base = entry.base;
341 dv->dv_size = entry.size;
342 } else {
343 /* Return a partition table entry and the geometry of the drive. */
344 entry.base = dv->dv_base;
345 entry.size = dv->dv_size;
346 (*dp->dr_geometry)(&entry);
347 if (OK != (s=sys_datacopy(SELF, (vir_bytes) &entry,
348 mp->PROC_NR, (vir_bytes) mp->ADDRESS, sizeof(entry))))
349 return s;
350 }
351 return(OK);
352}
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