sr.c

GNU Mach 微内核源代码, 基于美国卡内基美隆大学的 Mach 研究项目

/*
 *  sr.c Copyright (C) 1992 David Giller
 *	     Copyright (C) 1993, 1994, 1995 Eric Youngdale
 *
 *  adapted from:
 *	sd.c Copyright (C) 1992 Drew Eckhardt 
 *	Linux scsi disk driver by
 *		Drew Eckhardt <[e-mail]>
 *
 *      Modified by Eric Youngdale [e-mail] to
 *      add scatter-gather, multiple outstanding request, and other
 *      enhancements.
 *
 *	    Modified by Eric Youngdale [e-mail] to support loadable
 *	    low-level scsi drivers.
 *
 *	 Modified by Thomas Quinot [e-mail] to
 *	 provide auto-eject.
 *
 */

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/cdrom.h>
#include <linux/interrupt.h>
#include <asm/system.h>

#define MAJOR_NR SCSI_CDROM_MAJOR
#include <linux/blk.h>
#include "scsi.h"
#include "hosts.h"
#include "sr.h"
#include <scsi/scsi_ioctl.h>   /* For the door lock/unlock commands */
#include "constants.h"

#define MAX_RETRIES 3
#define SR_TIMEOUT (30 * HZ)

static int sr_init(void);
static void sr_finish(void);
static int sr_attach(Scsi_Device *);
static int sr_detect(Scsi_Device *);
static void sr_detach(Scsi_Device *);

struct Scsi_Device_Template sr_template = {NULL, "cdrom", "sr", NULL, TYPE_ROM, 
					       SCSI_CDROM_MAJOR, 0, 0, 0, 1,
					       sr_detect, sr_init,
					       sr_finish, sr_attach, sr_detach};

Scsi_CD * scsi_CDs = NULL;
static int * sr_sizes;

static int * sr_blocksizes;

static int sr_open(struct inode *, struct file *);
void get_sectorsize(int);
void sr_photocd(struct inode *);

extern int sr_ioctl(struct inode *, struct file *, unsigned int, unsigned long);

void requeue_sr_request (Scsi_Cmnd * SCpnt);
static int check_cdrom_media_change(kdev_t);

static void sr_release(struct inode * inode, struct file * file)
{
	sync_dev(inode->i_rdev);
	if(! --scsi_CDs[MINOR(inode->i_rdev)].device->access_count)
	{
	    sr_ioctl(inode, NULL, SCSI_IOCTL_DOORUNLOCK, 0);
	    if (scsi_CDs[MINOR(inode->i_rdev)].auto_eject)
		sr_ioctl(inode, NULL, CDROMEJECT, 0);
	}
	if (scsi_CDs[MINOR(inode->i_rdev)].device->host->hostt->usage_count)
	    (*scsi_CDs[MINOR(inode->i_rdev)].device->host->hostt->usage_count)--;
	if(sr_template.usage_count) (*sr_template.usage_count)--;
}

static struct file_operations sr_fops = 
{
	NULL,			/* lseek - default */
	block_read,		/* read - general block-dev read */
	block_write,		/* write - general block-dev write */
	NULL,			/* readdir - bad */
	NULL,			/* select */
	sr_ioctl,		/* ioctl */
	NULL,			/* mmap */
	sr_open,       	/* special open code */
	sr_release,		/* release */
	NULL,			/* fsync */
	NULL,			/* fasync */
	check_cdrom_media_change,  /* Disk change */
	NULL			/* revalidate */
};

/*
 * This function checks to see if the media has been changed in the
 * CDROM drive.  It is possible that we have already sensed a change,
 * or the drive may have sensed one and not yet reported it.  We must
 * be ready for either case. This function always reports the current
 * value of the changed bit.  If flag is 0, then the changed bit is reset.
 * This function could be done as an ioctl, but we would need to have
 * an inode for that to work, and we do not always have one.
 */

int check_cdrom_media_change(kdev_t full_dev){
	int retval, target;
	struct inode inode;
	int flag = 0;
    
	target =  MINOR(full_dev);
    
	if (target >= sr_template.nr_dev) {
		printk("CD-ROM request error: invalid device.\n");
		return 0;
	};
    
	inode.i_rdev = full_dev;  /* This is all we really need here */
	retval = sr_ioctl(&inode, NULL, SCSI_IOCTL_TEST_UNIT_READY, 0);
    
	if(retval){ /* Unable to test, unit probably not ready.  This usually
		 * means there is no disc in the drive.  Mark as changed,
		 * and we will figure it out later once the drive is
		 * available again.  */
	
	scsi_CDs[target].device->changed = 1;
	return 1; /* This will force a flush, if called from
		   * check_disk_change */
	};
    
	retval = scsi_CDs[target].device->changed;
	if(!flag) {
	scsi_CDs[target].device->changed = 0;
	/* If the disk changed, the capacity will now be different,
	 * so we force a re-read of this information */
	if (retval) scsi_CDs[target].needs_sector_size = 1;
	};
	return retval;
}

/*
 * rw_intr is the interrupt routine for the device driver.  It will be notified on the 
 * end of a SCSI read / write, and will take on of several actions based on success or failure.
 */

static void rw_intr (Scsi_Cmnd * SCpnt)
{
	int result = SCpnt->result;
	int this_count = SCpnt->this_count;
	int good_sectors = (result == 0 ? this_count : 0);
	int block_sectors = 0;
    
#ifdef DEBUG
	printk("sr.c done: %x %x\n",result, SCpnt->request.bh->b_data);
#endif
    /*
      Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial success.
      Since this is a relatively rare error condition, no care is taken to
      avoid unnecessary additional work such as memcpy's that could be avoided.
    */

	if (driver_byte(result) != 0 &&		    /* An error occurred */
	    SCpnt->sense_buffer[0] == 0xF0 &&	    /* Sense data is valid */
	    (SCpnt->sense_buffer[2] == MEDIUM_ERROR ||
	     SCpnt->sense_buffer[2] == VOLUME_OVERFLOW ||
	     SCpnt->sense_buffer[2] == ILLEGAL_REQUEST))
	  {
	    long error_sector = (SCpnt->sense_buffer[3] << 24) |
				(SCpnt->sense_buffer[4] << 16) |
				(SCpnt->sense_buffer[5] << 8) |
				SCpnt->sense_buffer[6];
	    int device_nr = DEVICE_NR(SCpnt->request.rq_dev);
	    if (SCpnt->request.bh != NULL)
	      block_sectors = SCpnt->request.bh->b_size >> 9;
	    if (block_sectors < 4) block_sectors = 4;
	    if (scsi_CDs[device_nr].sector_size == 2048)
	      error_sector <<= 2;
	    error_sector &= ~ (block_sectors - 1);
	    good_sectors = error_sector - SCpnt->request.sector;
	    if (good_sectors < 0 || good_sectors >= this_count)
	      good_sectors = 0;
	    /*
	      The SCSI specification allows for the value returned by READ
	      CAPACITY to be up to 75 2K sectors past the last readable
	      block.  Therefore, if we hit a medium error within the last
	      75 2K sectors, we decrease the saved size value.
	    */
	    if ((error_sector >> 1) < sr_sizes[device_nr] &&
		scsi_CDs[device_nr].capacity - error_sector < 4*75)
	      sr_sizes[device_nr] = error_sector >> 1;
	  }

	if (good_sectors > 0)
    { /* Some sectors were read successfully. */
	if (SCpnt->use_sg == 0) {
		    if (SCpnt->buffer != SCpnt->request.buffer)
	    {
		int offset;
		offset = (SCpnt->request.sector % 4) << 9;
		memcpy((char *)SCpnt->request.buffer, 
		       (char *)SCpnt->buffer + offset, 
		       good_sectors << 9);
		/* Even though we are not using scatter-gather, we look
		 * ahead and see if there is a linked request for the
		 * other half of this buffer.  If there is, then satisfy
		 * it. */
		if((offset == 0) && good_sectors == 2 &&
		   SCpnt->request.nr_sectors > good_sectors && 
		   SCpnt->request.bh &&
		   SCpnt->request.bh->b_reqnext &&
		   SCpnt->request.bh->b_reqnext->b_size == 1024) {
		    memcpy((char *)SCpnt->request.bh->b_reqnext->b_data, 
			   (char *)SCpnt->buffer + 1024, 
			   1024);
		    good_sectors += 2;
		};
		
		scsi_free(SCpnt->buffer, 2048);
	    }
	} else {
		    struct scatterlist * sgpnt;
		    int i;
		    sgpnt = (struct scatterlist *) SCpnt->buffer;
		    for(i=0; i<SCpnt->use_sg; i++) {
		if (sgpnt[i].alt_address) {
		    if (sgpnt[i].alt_address != sgpnt[i].address) {
			memcpy(sgpnt[i].alt_address, sgpnt[i].address, sgpnt[i].length);
		    };
		    scsi_free(sgpnt[i].address, sgpnt[i].length);
		};
		    };
		    scsi_free(SCpnt->buffer, SCpnt->sglist_len);  /* Free list of scatter-gather pointers */
		    if(SCpnt->request.sector % 4) good_sectors -= 2;
	    /* See   if there is a padding record at the end that needs to be removed */
		    if(good_sectors > SCpnt->request.nr_sectors)
		good_sectors -= 2;
	};
	
#ifdef DEBUG
		printk("(%x %x %x) ",SCpnt->request.bh, SCpnt->request.nr_sectors, 
		       good_sectors);
#endif
		if (SCpnt->request.nr_sectors > this_count)
	{	 
			SCpnt->request.errors = 0;
			if (!SCpnt->request.bh)
			    panic("sr.c: linked page request (%lx %x)",
		      SCpnt->request.sector, this_count);
	}
	
	SCpnt = end_scsi_request(SCpnt, 1, good_sectors);  /* All done */
	if (result == 0)
	  {
	    requeue_sr_request(SCpnt);
	    return;
	  }
    }
    
    if (good_sectors == 0) {
	/* We only come through here if no sectors were read successfully. */
    
    /* Free up any indirection buffers we allocated for DMA purposes. */
	if (SCpnt->use_sg) {
	struct scatterlist * sgpnt;
	int i;
	sgpnt = (struct scatterlist *) SCpnt->buffer;
	for(i=0; i<SCpnt->use_sg; i++) {
	    if (sgpnt[i].alt_address) {
		scsi_free(sgpnt[i].address, sgpnt[i].length);
	    }
	}
	scsi_free(SCpnt->buffer, SCpnt->sglist_len);  /* Free list of scatter-gather pointers */
	} else {
	if (SCpnt->buffer != SCpnt->request.buffer)
	    scsi_free(SCpnt->buffer, SCpnt->bufflen);
	}
    
    }

	if (driver_byte(result) != 0) {
		if ((SCpnt->sense_buffer[0] & 0x7f) == 0x70) {
			if ((SCpnt->sense_buffer[2] & 0xf) == UNIT_ATTENTION) {
				/* detected disc change.  set a bit and quietly refuse 
				 * further access.	*/
		
				scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].device->changed = 1;
				SCpnt = end_scsi_request(SCpnt, 0, this_count);
				requeue_sr_request(SCpnt);
				return;
			}
		}
	    
		if (SCpnt->sense_buffer[2] == ILLEGAL_REQUEST) {
			printk("CD-ROM error: ");
			print_sense("sr", SCpnt);
			printk("command was: ");
			print_command(SCpnt->cmnd);
			if (scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].ten) {
				scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].ten = 0;
				requeue_sr_request(SCpnt);
				result = 0;
				return;
			} else {
				SCpnt = end_scsi_request(SCpnt, 0, this_count);
				requeue_sr_request(SCpnt); /* Do next request */
				return;
			}
	    
		}

		if (SCpnt->sense_buffer[2] == NOT_READY) {
			printk("CD-ROM not ready.  Make sure you have a disc in the drive.\n");
			SCpnt = end_scsi_request(SCpnt, 0, this_count);
			requeue_sr_request(SCpnt); /* Do next request */
			return;
		}

		if (SCpnt->sense_buffer[2] == MEDIUM_ERROR) {
		    printk("scsi%d: MEDIUM ERROR on "
			   "channel %d, id %d, lun %d, CDB: ",
			   SCpnt->host->host_no, (int) SCpnt->channel, 
			   (int) SCpnt->target, (int) SCpnt->lun);
		    print_command(SCpnt->cmnd);
		    print_sense("sr", SCpnt);
		    SCpnt = end_scsi_request(SCpnt, 0, block_sectors);
		    requeue_sr_request(SCpnt);
		    return;
		}

		if (SCpnt->sense_buffer[2] == VOLUME_OVERFLOW) {
		    printk("scsi%d: VOLUME OVERFLOW on "
			   "channel %d, id %d, lun %d, CDB: ",
			   SCpnt->host->host_no, (int) SCpnt->channel, 
			   (int) SCpnt->target, (int) SCpnt->lun);
		    print_command(SCpnt->cmnd);
		    print_sense("sr", SCpnt);
		    SCpnt = end_scsi_request(SCpnt, 0, block_sectors);
		    requeue_sr_request(SCpnt);
		    return;
		}
    }
	
	/* We only get this far if we have an error we have not recognized */
	if(result) {
	printk("SCSI CD error : host %d id %d lun %d return code = %03x\n", 
	       scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].device->host->host_no, 
	       scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].device->id,
	       scsi_CDs[DEVICE_NR(SCpnt->request.rq_dev)].device->lun,
	       result);
	    
	if (status_byte(result) == CHECK_CONDITION)
	    print_sense("sr", SCpnt);
	
	SCpnt = end_scsi_request(SCpnt, 0, SCpnt->request.current_nr_sectors);
	requeue_sr_request(SCpnt);
    }
}

/*
 * Here I tried to implement support for multisession-CD's
 * 
 * Much of this has do be done with vendor-specific SCSI-commands, because
 * multisession is newer than the SCSI-II standard.
 * So I have to complete it step by step. Useful information is welcome.
 *
 * Actually works:
 *   - NEC:     Detection and support of multisession CD's. Special handling
 *              for XA-disks is not necessary.
 *     
 *   - TOSHIBA: setting density is done here now, mounting PhotoCD's should
 *              work now without running the program "set_density"
 *              Multisession CD's are supported too.
 *
 *   Gerd Knorr <[e-mail]> 
 */
/*
 * 19950704 [e-mail] (Thomas Quinot)
 *
 *   - SONY:	Same as Nec.
 *
 *   - PIONEER: works with SONY code (may be others too ?)
 */

void sr_photocd(struct inode *inode)
{
    unsigned long   sector,min,sec,frame;
    unsigned char   buf[40];    /* the buffer for the ioctl */
    unsigned char   *cmd;       /* the scsi-command */
    unsigned char   *send;      /* the data we send to the drive ... */
    unsigned char   *rec;       /* ... and get back */
    int             rc,is_xa,no_multi;
    
    if (scsi_CDs[MINOR(inode->i_rdev)].xa_flags & 0x02) {
#ifdef DEBUG
	printk(KERN_DEBUG "sr_photocd: CDROM and/or driver do not support multisession CD's");
#endif
	return;
    }
    
    if (!suser()) {
	/* I'm not the superuser, so SCSI_IOCTL_SEND_COMMAND isn't allowed
         * for me. That's why mpcd_sector will be initialized with zero,
         * because I'm not able to get the right value. Necessary only if
         * access_count is 1, else no disk change happened since the last
         * call of this function and we can keep the old value.
	 */
	if (1 == scsi_CDs[MINOR(inode->i_rdev)].device->access_count) {
	    scsi_CDs[MINOR(inode->i_rdev)].mpcd_sector = 0;
	    scsi_CDs[MINOR(inode->i_rdev)].xa_flags &= ~0x01;
	}
	return;
    }
    
    sector   = 0;
    is_xa    = 0;
    no_multi = 0;
    cmd = rec = &buf[8];
    
    switch(scsi_CDs[MINOR(inode->i_rdev)].device->manufacturer) {
	
    case SCSI_MAN_NEC:
#ifdef DEBUG
	printk(KERN_DEBUG "sr_photocd: use NEC code\n");
#endif
	memset(buf,0,40);
	*((unsigned int*)buf)   = 0x0;   /* we send nothing...     */