Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/drivers/libdriver/driver.c
Version:
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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 #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. */ 52 PRIVATE u8_t buffer[(unsigned) 2 * DMA_BUF_SIZE + BUF_EXTRA]; 53 u8_t *tmp_buf; /* the DMA buffer eventually */ 54 phys_bytes tmp_phys; /* phys address of DMA buffer */ 55 56 #else /* CHIP != INTEL */ 57 58 /* Claim space for variables. */ 59 u8_t tmp_buf[DMA_BUF_SIZE]; /* the DMA buffer */ 60 phys_bytes tmp_phys; /* phys address of DMA buffer */ 61 62 #endif /* CHIP != INTEL */ 63 64 FORWARD _PROTOTYPE( void init_buffer, (void) ); 65 FORWARD _PROTOTYPE( int do_rdwt, (struct driver *dr, message *mp) ); 66 FORWARD _PROTOTYPE( int do_vrdwt, (struct driver *dr, message *mp) ); 67 68 int device_caller; 69 70 /*===========================================================================* 71 * driver_task * 72 *===========================================================================*/ 73 PUBLIC void driver_task(dp) 74 struct 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.PROC_NR; 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 SYS_SIG: (*dp->dr_signal)(dp, &mess); 113 continue; /* don't reply */ 114 case SYN_ALARM: (*dp->dr_alarm)(dp, &mess); 115 continue; /* don't reply */ 116 case DEV_PING: notify(mess.m_source); 117 continue; 118 default: 119 if(dp->dr_other) 120 r = (*dp->dr_other)(dp, &mess); 121 else 122 r = EINVAL; 123 break; 124 } 125 126 /* Clean up leftover state. */ 127 (*dp->dr_cleanup)(); 128 129 /* Finally, prepare and send the reply message. */ 130 if (r != EDONTREPLY) { 131 mess.m_type = TASK_REPLY; 132 mess.REP_PROC_NR = proc_nr; 133 /* Status is # of bytes transferred or error code. */ 134 mess.REP_STATUS = r; 135 send(device_caller, &mess); 136 } 137 } 138 } 139 140 141 /*===========================================================================* 142 * init_buffer * 143 *===========================================================================*/ 144 PRIVATE void init_buffer() 145 { 146 /* Select a buffer that can safely be used for DMA transfers. It may also 147 * be used to read partition tables and such. Its absolute address is 148 * 'tmp_phys', the normal address is 'tmp_buf'. 149 */ 150 151 #if (CHIP == INTEL) 152 unsigned left; 153 154 tmp_buf = buffer; 155 sys_umap(SELF, D, (vir_bytes)buffer, (phys_bytes)sizeof(buffer), &tmp_phys); 156 157 if ((left = dma_bytes_left(tmp_phys)) < DMA_BUF_SIZE) { 158 /* First half of buffer crosses a 64K boundary, can't DMA into that */ 159 tmp_buf += left; 160 tmp_phys += left; 161 } 162 #endif /* CHIP == INTEL */ 163 } 164 165 /*===========================================================================* 166 * do_rdwt * 167 *===========================================================================*/ 168 PRIVATE int do_rdwt(dp, mp) 169 struct driver *dp; /* device dependent entry points */ 170 message *mp; /* pointer to read or write message */ 171 { 172 /* Carry out a single read or write request. */ 173 iovec_t iovec1; 174 int r, opcode; 175 phys_bytes phys_addr; 176 177 /* Disk address? Address and length of the user buffer? */ 178 if (mp->COUNT < 0) return(EINVAL); 179 180 /* Check the user buffer. */ 181 sys_umap(mp->PROC_NR, D, (vir_bytes) mp->ADDRESS, mp->COUNT, &phys_addr); 182 if (phys_addr == 0) return(EFAULT); 183 184 /* Prepare for I/O. */ 185 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO); 186 187 /* Create a one element scatter/gather vector for the buffer. */ 188 opcode = mp->m_type == DEV_READ ? DEV_GATHER : DEV_SCATTER; 189 iovec1.iov_addr = (vir_bytes) mp->ADDRESS; 190 iovec1.iov_size = mp->COUNT; 191 192 /* Transfer bytes from/to the device. */ 193 r = (*dp->dr_transfer)(mp->PROC_NR, opcode, mp->POSITION, &iovec1, 1); 194 195 /* Return the number of bytes transferred or an error code. */ 196 return(r == OK ? (mp->COUNT - iovec1.iov_size) : r); 197 } 198 199 /*==========================================================================* 200 * do_vrdwt * 201 *==========================================================================*/ 202 PRIVATE int do_vrdwt(dp, mp) 203 struct driver *dp; /* device dependent entry points */ 204 message *mp; /* pointer to read or write message */ 205 { 206 /* Carry out an device read or write to/from a vector of user addresses. 207 * The "user addresses" are assumed to be safe, i.e. FS transferring to/from 208 * its own buffers, so they are not checked. 209 */ 210 static iovec_t iovec[NR_IOREQS]; 211 iovec_t *iov; 212 phys_bytes iovec_size; 213 unsigned nr_req; 214 int r; 215 216 nr_req = mp->COUNT; /* Length of I/O vector */ 217 218 if (mp->m_source < 0) { 219 /* Called by a task, no need to copy vector. */ 220 iov = (iovec_t *) mp->ADDRESS; 221 } else { 222 /* Copy the vector from the caller to kernel space. */ 223 if (nr_req > NR_IOREQS) nr_req = NR_IOREQS; 224 iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0])); 225 226 if (OK != sys_datacopy(mp->m_source, (vir_bytes) mp->ADDRESS, 227 SELF, (vir_bytes) iovec, iovec_size)) 228 panic((*dp->dr_name)(),"bad I/O vector by", mp->m_source); 229 iov = iovec; 230 } 231 232 /* Prepare for I/O. */ 233 if ((*dp->dr_prepare)(mp->DEVICE) == NIL_DEV) return(ENXIO); 234 235 /* Transfer bytes from/to the device. */ 236 r = (*dp->dr_transfer)(mp->PROC_NR, mp->m_type, mp->POSITION, iov, nr_req); 237 238 /* Copy the I/O vector back to the caller. */ 239 if (mp->m_source >= 0) { 240 sys_datacopy(SELF, (vir_bytes) iovec, 241 mp->m_source, (vir_bytes) mp->ADDRESS, iovec_size); 242 } 243 return(r); 244 } 245 246 /*===========================================================================* 247 * no_name * 248 *===========================================================================*/ 249 PUBLIC char *no_name() 250 { 251 /* Use this default name if there is no specific name for the device. This was 252 * originally done by fetching the name from the task table for this process: 253 * "return(tasktab[proc_number(proc_ptr) + NR_TASKS].name);", but currently a 254 * real "noname" is returned. Perhaps, some system information service can be 255 * queried for a name at a later time. 256 */ 257 static char name[] = "noname"; 258 return name; 259 } 260 261 /*============================================================================* 262 * do_nop * 263 *============================================================================*/ 264 PUBLIC int do_nop(dp, mp) 265 struct driver *dp; 266 message *mp; 267 { 268 /* Nothing there, or nothing to do. */ 269 270 switch (mp->m_type) { 271 case DEV_OPEN: return(ENODEV); 272 case DEV_CLOSE: return(OK); 273 case DEV_IOCTL: return(ENOTTY); 274 default: return(EIO); 275 } 276 } 277 278 /*============================================================================* 279 * nop_signal * 280 *============================================================================*/ 281 PUBLIC void nop_signal(dp, mp) 282 struct driver *dp; 283 message *mp; 284 { 285 /* Default action for signal is to ignore. */ 286 } 287 288 /*============================================================================* 289 * nop_alarm * 290 *============================================================================*/ 291 PUBLIC void nop_alarm(dp, mp) 292 struct driver *dp; 293 message *mp; 294 { 295 /* Ignore the leftover alarm. */ 296 } 297 298 /*===========================================================================* 299 * nop_prepare * 300 *===========================================================================*/ 301 PUBLIC struct device *nop_prepare(device) 302 { 303 /* Nothing to prepare for. */ 304 return(NIL_DEV); 305 } 306 307 /*===========================================================================* 308 * nop_cleanup * 309 *===========================================================================*/ 310 PUBLIC void nop_cleanup() 311 { 312 /* Nothing to clean up. */ 313 } 314 315 /*===========================================================================* 316 * nop_cancel * 317 *===========================================================================*/ 318 PUBLIC int nop_cancel(struct driver *dr, message *m) 319 { 320 /* Nothing to do for cancel. */ 321 return(OK); 322 } 323 324 /*===========================================================================* 325 * nop_select * 326 *===========================================================================*/ 327 PUBLIC int nop_select(struct driver *dr, message *m) 328 { 329 /* Nothing to do for select. */ 330 return(OK); 331 } 332 333 /*============================================================================* 334 * do_diocntl * 335 *============================================================================*/ 336 PUBLIC int do_diocntl(dp, mp) 337 struct driver *dp; 338 message *mp; /* pointer to ioctl request */ 339 { 340 /* Carry out a partition setting/getting request. */ 341 struct device *dv; 342 struct partition entry; 343 int s; 344 345 if (mp->REQUEST != DIOCSETP && mp->REQUEST != DIOCGETP) { 346 if(dp->dr_other) { 347 return dp->dr_other(dp, mp); 348 } else return(ENOTTY); 349 } 350 351 /* Decode the message parameters. */ 352 if ((dv = (*dp->dr_prepare)(mp->DEVICE)) == NIL_DEV) return(ENXIO); 353 354 if (mp->REQUEST == DIOCSETP) { 355 /* Copy just this one partition table entry. */ 356 if (OK != (s=sys_datacopy(mp->PROC_NR, (vir_bytes) mp->ADDRESS, 357 SELF, (vir_bytes) &entry, sizeof(entry)))) 358 return s; 359 dv->dv_base = entry.base; 360 dv->dv_size = entry.size; 361 } else { 362 /* Return a partition table entry and the geometry of the drive. */ 363 entry.base = dv->dv_base; 364 entry.size = dv->dv_size; 365 (*dp->dr_geometry)(&entry); 366 if (OK != (s=sys_datacopy(SELF, (vir_bytes) &entry, 367 mp->PROC_NR, (vir_bytes) mp->ADDRESS, sizeof(entry)))) 368 return s; 369 } 370 return(OK); 371 }
Cache object: 692dc8a553541265270185ff63711368
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