driver.h

一个简单的操作系统minix的核心代码

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				src/kernel/driver.h	 	 
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09000	/* Types and constants shared between the generic and device dependent
09001	 * device driver code.
09002	 */
09003	
09004	#include <minix/callnr.h>
09005	#include <minix/com.h>
09006	#include "proc.h"
09007	#include <minix/partition.h>
09008	
09009	/* Info about and entry points into the device dependent code. */
09010	struct driver {
09011	  _PROTOTYPE( char *(*dr_name), (void) );
09012	  _PROTOTYPE( int (*dr_open), (struct driver *dp, message *m_ptr) );
09013	  _PROTOTYPE( int (*dr_close), (struct driver *dp, message *m_ptr) );
09014	  _PROTOTYPE( int (*dr_ioctl), (struct driver *dp, message *m_ptr) );
09015	  _PROTOTYPE( struct device *(*dr_prepare), (int device) );
09016	  _PROTOTYPE( int (*dr_schedule), (int proc_nr, struct iorequest_s *request) );
09017	  _PROTOTYPE( int (*dr_finish), (void) );
09018	  _PROTOTYPE( void (*dr_cleanup), (void) );
09019	  _PROTOTYPE( void (*dr_geometry), (struct partition *entry) );
09020	};
09021	
09022	#if (CHIP == INTEL)
09023	
09024	/* Number of bytes you can DMA before hitting a 64K boundary: */
09025	#define dma_bytes_left(phys)    \
09026	   ((unsigned) (sizeof(int) == 2 ? 0 : 0x10000) - (unsigned) ((phys) & 0xFFFF))
09027	
09028	#endif /* CHIP == INTEL */
09029	
09030	/* Base and size of a partition in bytes. */
09031	struct device {
09032	  unsigned long dv_base;
09033	  unsigned long dv_size;
09034	};
09035	
09036	#define NIL_DEV         ((struct device *) 0)
09037	
09038	/* Functions defined by driver.c: */
09039	_PROTOTYPE( void driver_task, (struct driver *dr) );
09040	_PROTOTYPE( int do_rdwt, (struct driver *dr, message *m_ptr) );
09041	_PROTOTYPE( int do_vrdwt, (struct driver *dr, message *m_ptr) );
09042	_PROTOTYPE( char *no_name, (void) );
09043	_PROTOTYPE( int do_nop, (struct driver *dp, message *m_ptr) );
09044	_PROTOTYPE( int nop_finish, (void) );
09045	_PROTOTYPE( void nop_cleanup, (void) );
09046	_PROTOTYPE( void clock_mess, (int ticks, watchdog_t func) );
09047	_PROTOTYPE( int do_diocntl, (struct driver *dr, message *m_ptr) );
09048	
09049	/* Parameters for the disk drive. */
09050	#define SECTOR_SIZE      512    /* physical sector size in bytes */
09051	#define SECTOR_SHIFT       9    /* for division */
09052	#define SECTOR_MASK      511    /* and remainder */
09053	
09054	/* Size of the DMA buffer buffer in bytes. */
09055	#define DMA_BUF_SIZE    (DMA_SECTORS * SECTOR_SIZE)
09056	
09057	#if (CHIP == INTEL)
09058	extern u8_t *tmp_buf;                   /* the DMA buffer */
09059	#else
09060	extern u8_t tmp_buf[];                  /* the DMA buffer */
09061	#endif
09062	extern phys_bytes tmp_phys;             /* phys address of DMA buffer */

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				src/kernel/driver.c	 	 
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09100	/* This file contains device independent device driver interface.
09101	 *                                                      Author: Kees J. Bot.
09102	 *
09103	 * The drivers support the following operations (using message format m2):
09104	 *
09105	 *    m_type      DEVICE    PROC_NR     COUNT    POSITION  ADRRESS
09106	 * ----------------------------------------------------------------
09107	 * |  DEV_OPEN  | device  | proc nr |         |         |         |
09108	 * |------------+---------+---------+---------+---------+---------|
09109	 * |  DEV_CLOSE | device  | proc nr |         |         |         |
09110	 * |------------+---------+---------+---------+---------+---------|
09111	 * |  DEV_READ  | device  | proc nr |  bytes  |  offset | buf ptr |
09112	 * |------------+---------+---------+---------+---------+---------|
09113	 * |  DEV_WRITE | device  | proc nr |  bytes  |  offset | buf ptr |
09114	 * |------------+---------+---------+---------+---------+---------|
09115	 * |SCATTERED_IO| device  | proc nr | requests|         | iov ptr |
09116	 * ----------------------------------------------------------------
09117	 * |  DEV_IOCTL | device  | proc nr |func code|         | buf ptr |
09118	 * ----------------------------------------------------------------
09119	 *
09120	 * The file contains one entry point:
09121	 *
09122	 *   driver_task:       called by the device dependent task entry
09123	 *
09124	 *
09125	 * Constructed 92/04/02 by Kees J. Bot from the old AT wini and floppy driver.
09126	 */
09127	
09128	#include "kernel.h"
09129	#include <sys/ioctl.h>
09130	#include "driver.h"
09131	
09132	#define BUF_EXTRA       0
09133	
09134	/* Claim space for variables. */
09135	PRIVATE u8_t buffer[(unsigned) 2 * DMA_BUF_SIZE + BUF_EXTRA];
09136	u8_t *tmp_buf;                  /* the DMA buffer eventually */
09137	phys_bytes tmp_phys;            /* phys address of DMA buffer */
09138	
09139	FORWARD _PROTOTYPE( void init_buffer, (void) );
09140	
09141	/*===========================================================================*
09142	 *                              driver_task                                  *
09143	 *===========================================================================*/
09144	PUBLIC void driver_task(dp)
09145	struct driver *dp;      /* Device dependent entry points. */
09146	{
09147	/* Main program of any device driver task. */
09148	
09149	  int r, caller, proc_nr;
09150	  message mess;
09151	
09152	  init_buffer();        /* Get a DMA buffer. */
09153	
09154	  /* Here is the main loop of the disk task.  It waits for a message, carries
09155	   * it out, and sends a reply.
09156	   */
09157	
09158	  while (TRUE) {
09159	        /* First wait for a request to read or write a disk block. */
09160	        receive(ANY, &mess);
09161	
09162	        caller = mess.m_source;
09163	        proc_nr = mess.PROC_NR;
09164	
09165	        switch (caller) {
09166	        case HARDWARE:
09167	                /* Leftover interrupt. */
09168	                continue;
09169	        case FS_PROC_NR:
09170	                /* The only legitimate caller. */
09171	                break;
09172	        default:
09173	                printf("%s: got message from %d\n", (*dp->dr_name)(), caller);
09174	                continue;
09175	        }
09176	
09177	        /* Now carry out the work. */
09178	        switch(mess.m_type) {
09179	            case DEV_OPEN:      r = (*dp->dr_open)(dp, &mess);  break;
09180	            case DEV_CLOSE:     r = (*dp->dr_close)(dp, &mess); break;
09181	            case DEV_IOCTL:     r = (*dp->dr_ioctl)(dp, &mess); break;
09182	
09183	            case DEV_READ:
09184	            case DEV_WRITE:     r = do_rdwt(dp, &mess);         break;
09185	
09186	            case SCATTERED_IO:  r = do_vrdwt(dp, &mess);        break;
09187	            default:            r = EINVAL;                     break;
09188	        }
09189	
09190	        /* Clean up leftover state. */
09191	        (*dp->dr_cleanup)();
09192	
09193	        /* Finally, prepare and send the reply message. */
09194	        mess.m_type = TASK_REPLY;
09195	        mess.REP_PROC_NR = proc_nr;
09196	
09197	        mess.REP_STATUS = r;    /* # of bytes transferred or error code */
09198	        send(caller, &mess);    /* send reply to caller */
09199	  }
09200	}
	
09202	/*===========================================================================*
09203	 *                              init_buffer                                  *
09204	 *===========================================================================*/
09205	PRIVATE void init_buffer()
09206	{
09207	/* Select a buffer that can safely be used for dma transfers.  It may also
09208	 * be used to read partition tables and such.  Its absolute address is
09209	 * 'tmp_phys', the normal address is 'tmp_buf'.
09210	 */
09211	
09212	  tmp_buf = buffer;
09213	  tmp_phys = vir2phys(buffer);
09214	
09215	  if (tmp_phys == 0) panic("no DMA buffer", NO_NUM);
09216	
09217	  if (dma_bytes_left(tmp_phys) < DMA_BUF_SIZE) {
09218	        /* First half of buffer crosses a 64K boundary, can't DMA into that */
09219	        tmp_buf += DMA_BUF_SIZE;