sd.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

	 * So I have created this table. See ll_rw_blk.c
	 * Jacques Gelinas ([e-mail])
	 */
	int m, mb;
        int sz_quot, sz_rem;
	int hard_sector = rscsi_disks[i].sector_size;
	/* There are 16 minors allocated for each major device */
	for (m=i<<4; m<((i+1)<<4); m++){
	    sd_hardsizes[m] = hard_sector;
	}
        mb = rscsi_disks[i].capacity / 1024 * hard_sector / 1024;
        /* sz = div(m/100, 10);  this seems to not be in the libr */
        m = (mb + 50) / 100;
        sz_quot = m / 10;
        sz_rem = m - (10 * sz_quot);
#ifdef MACH
	printk ("SCSI device sd%d: hdwr sector= %d bytes."
               " Sectors= %d [%d MB] [%d.%1d GB]\n",
		i, hard_sector, rscsi_disks[i].capacity, 
                mb, sz_quot, sz_rem);
#else
	printk ("SCSI device sd%c: hdwr sector= %d bytes."
               " Sectors= %d [%d MB] [%d.%1d GB]\n",
		i+'a', hard_sector, rscsi_disks[i].capacity, 
                mb, sz_quot, sz_rem);
#endif
    }
	if(rscsi_disks[i].sector_size == 1024)
	    rscsi_disks[i].capacity <<= 1;  /* Change into 512 byte sectors */
	if(rscsi_disks[i].sector_size == 256)
	    rscsi_disks[i].capacity >>= 1;  /* Change into 512 byte sectors */
    }
    

    /*
     * Unless otherwise specified, this is not write protected.
     */
    rscsi_disks[i].write_prot = 0;
    if ( rscsi_disks[i].device->removable && rscsi_disks[i].ready ) {
	/* FLOPTICAL */

	/* 
	 *	for removable scsi disk ( FLOPTICAL ) we have to recognise  
	 * the Write Protect Flag. This flag is kept in the Scsi_Disk struct
	 * and tested at open !
	 * Daniel Roche ( [e-mail] )
	 */
	
	memset ((void *) &cmd[0], 0, 8);
	cmd[0] = MODE_SENSE;
	cmd[1] = (rscsi_disks[i].device->lun << 5) & 0xe0;
	cmd[2] = 1;	 /* page code 1 ?? */
	cmd[4] = 12;
	SCpnt->cmd_len = 0;
	SCpnt->sense_buffer[0] = 0;
	SCpnt->sense_buffer[2] = 0;

	/* same code as READCAPA !! */
	{
	    struct semaphore sem = MUTEX_LOCKED;
	    SCpnt->request.rq_status = RQ_SCSI_BUSY;  /* Mark as really busy again */
	    SCpnt->request.sem = &sem;
	    scsi_do_cmd (SCpnt,
			 (void *) cmd, (void *) buffer,
			 512, sd_init_done,  SD_TIMEOUT,
			 MAX_RETRIES);
	    down(&sem);
	}
	
	the_result = SCpnt->result;
	SCpnt->request.rq_status = RQ_INACTIVE;  /* Mark as not busy */
	wake_up(&SCpnt->device->device_wait); 
	
	if ( the_result ) {
#ifdef MACH
	    printk ("sd%d: test WP failed, assume Write Protected\n",i);
#else
	    printk ("sd%c: test WP failed, assume Write Protected\n",i+'a');
#endif
	    rscsi_disks[i].write_prot = 1;
	} else {
	    rscsi_disks[i].write_prot = ((buffer[2] & 0x80) != 0);
#ifdef MACH
	    printk ("sd%d: Write Protect is %s\n",i,
	            rscsi_disks[i].write_prot ? "on" : "off");
#else
	    printk ("sd%c: Write Protect is %s\n",i+'a',
	            rscsi_disks[i].write_prot ? "on" : "off");
#endif
	}
	
    }	/* check for write protect */
 
    rscsi_disks[i].ten = 1;
    rscsi_disks[i].remap = 1;
    scsi_free(buffer, 512);
    return i;
}

/*
 * The sd_init() function looks at all SCSI drives present, determines
 * their size, and reads partition table entries for them.
 */

static int sd_registered = 0;

static int sd_init()
{
    int i;
    
    if (sd_template.dev_noticed == 0) return 0;
    
    if(!sd_registered) {
	  if (register_blkdev(MAJOR_NR,"sd",&sd_fops)) {
	      printk("Unable to get major %d for SCSI disk\n",MAJOR_NR);
	      return 1;
	  }
	  sd_registered++;
      }
    
    /* We do not support attaching loadable devices yet. */
    if(rscsi_disks) return 0;
    
    sd_template.dev_max = sd_template.dev_noticed + SD_EXTRA_DEVS;
    
    rscsi_disks = (Scsi_Disk *) 
	scsi_init_malloc(sd_template.dev_max * sizeof(Scsi_Disk), GFP_ATOMIC);
    memset(rscsi_disks, 0, sd_template.dev_max * sizeof(Scsi_Disk));
    
    sd_sizes = (int *) scsi_init_malloc((sd_template.dev_max << 4) * 
					sizeof(int), GFP_ATOMIC);
    memset(sd_sizes, 0, (sd_template.dev_max << 4) * sizeof(int));
    
    sd_blocksizes = (int *) scsi_init_malloc((sd_template.dev_max << 4) * 
					     sizeof(int), GFP_ATOMIC);
    
    sd_hardsizes = (int *) scsi_init_malloc((sd_template.dev_max << 4) * 
					    sizeof(int), GFP_ATOMIC);
    
    for(i=0;i<(sd_template.dev_max << 4);i++){
	sd_blocksizes[i] = 1024;
	sd_hardsizes[i] = 512;
    }
    blksize_size[MAJOR_NR] = sd_blocksizes;
    hardsect_size[MAJOR_NR] = sd_hardsizes;
    sd = (struct hd_struct *) scsi_init_malloc((sd_template.dev_max << 4) *
					       sizeof(struct hd_struct),
					       GFP_ATOMIC);
    
    
    sd_gendisk.max_nr = sd_template.dev_max;
    sd_gendisk.part = sd;
    sd_gendisk.sizes = sd_sizes;
    sd_gendisk.real_devices = (void *) rscsi_disks;
    return 0;
}

static void sd_finish(void)
{
    struct gendisk *gendisk;
    int i;

    blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
    
    for (gendisk = gendisk_head; gendisk != NULL; gendisk = gendisk->next)
      if (gendisk == &sd_gendisk)
	break;
    if (gendisk == NULL)
      {
	sd_gendisk.next = gendisk_head;
	gendisk_head = &sd_gendisk;
      }
    
    for (i = 0; i < sd_template.dev_max; ++i)
	if (!rscsi_disks[i].capacity && 
	    rscsi_disks[i].device)
	{
	    if (MODULE_FLAG
		&& !rscsi_disks[i].has_part_table) {
		sd_sizes[i << 4] = rscsi_disks[i].capacity;
		/* revalidate does sd_init_onedisk via MAYBE_REINIT*/
		revalidate_scsidisk(MKDEV(MAJOR_NR, i << 4), 0);
	    }
	    else
	    	i=sd_init_onedisk(i);
	    rscsi_disks[i].has_part_table = 1;
	}
    
    /* If our host adapter is capable of scatter-gather, then we increase
     * the read-ahead to 16 blocks (32 sectors).  If not, we use
     * a two block (4 sector) read ahead. 
     */
    if(rscsi_disks[0].device && rscsi_disks[0].device->host->sg_tablesize)
	read_ahead[MAJOR_NR] = 120;  /* 120 sector read-ahead */
    else
	read_ahead[MAJOR_NR] = 4;  /* 4 sector read-ahead */

    return;
}

static int sd_detect(Scsi_Device * SDp){
    if(SDp->type != TYPE_DISK && SDp->type != TYPE_MOD) return 0;

#ifdef MACH
    printk("Detected scsi %sdisk sd%d at scsi%d, channel %d, id %d, lun %d\n", 
           SDp->removable ? "removable " : "",
	   sd_template.dev_noticed++,
	   SDp->host->host_no, SDp->channel, SDp->id, SDp->lun);
#else
    printk("Detected scsi %sdisk sd%c at scsi%d, channel %d, id %d, lun %d\n", 
           SDp->removable ? "removable " : "",
	   'a'+ (sd_template.dev_noticed++),
	   SDp->host->host_no, SDp->channel, SDp->id, SDp->lun);
#endif
    
    return 1;
}

static int sd_attach(Scsi_Device * SDp){
    Scsi_Disk * dpnt;
    int i;
    
    if(SDp->type != TYPE_DISK && SDp->type != TYPE_MOD) return 0;
    
    if(sd_template.nr_dev >= sd_template.dev_max) {
	SDp->attached--;
	return 1;
    }
    
    for(dpnt = rscsi_disks, i=0; i<sd_template.dev_max; i++, dpnt++) 
	if(!dpnt->device) break;
    
    if(i >= sd_template.dev_max) panic ("scsi_devices corrupt (sd)");
    
    SDp->scsi_request_fn = do_sd_request;
    rscsi_disks[i].device = SDp;
    rscsi_disks[i].has_part_table = 0;
    sd_template.nr_dev++;
    sd_gendisk.nr_real++;
    return 0;
}

#define DEVICE_BUSY rscsi_disks[target].device->busy
#define USAGE rscsi_disks[target].device->access_count
#define CAPACITY rscsi_disks[target].capacity
#define MAYBE_REINIT  sd_init_onedisk(target)
#define GENDISK_STRUCT sd_gendisk

/* This routine is called to flush all partitions and partition tables
 * for a changed scsi disk, and then re-read the new partition table.
 * If we are revalidating a disk because of a media change, then we
 * enter with usage == 0.  If we are using an ioctl, we automatically have
 * usage == 1 (we need an open channel to use an ioctl :-), so this
 * is our limit.
 */
int revalidate_scsidisk(kdev_t dev, int maxusage){
    int target;
    struct gendisk * gdev;
    unsigned long flags;
    int max_p;
    int start;
    int i;
    
    target =  DEVICE_NR(dev);
    gdev = &GENDISK_STRUCT;
    
    save_flags(flags);
    cli();
    if (DEVICE_BUSY || USAGE > maxusage) {
	restore_flags(flags);
	printk("Device busy for revalidation (usage=%d)\n", USAGE);
	return -EBUSY;
    }
    DEVICE_BUSY = 1;
    restore_flags(flags);
    
    max_p = gdev->max_p;
    start = target << gdev->minor_shift;
    
    for (i=max_p - 1; i >=0 ; i--) {
	int minor = start+i;
	kdev_t devi = MKDEV(MAJOR_NR, minor);
	sync_dev(devi);
	invalidate_inodes(devi);
	invalidate_buffers(devi);
	gdev->part[minor].start_sect = 0;
	gdev->part[minor].nr_sects = 0;
        /*
         * Reset the blocksize for everything so that we can read
         * the partition table.
         */
        blksize_size[MAJOR_NR][minor] = 1024;
    }
    
#ifdef MAYBE_REINIT
    MAYBE_REINIT;
#endif
    
    gdev->part[start].nr_sects = CAPACITY;
    resetup_one_dev(gdev, target);
    
    DEVICE_BUSY = 0;
    return 0;
}

static int fop_revalidate_scsidisk(kdev_t dev){
    return revalidate_scsidisk(dev, 0);
}


static void sd_detach(Scsi_Device * SDp)
{
    Scsi_Disk * dpnt;
    int i;
    int max_p;
    int start;
    
    for(dpnt = rscsi_disks, i=0; i<sd_template.dev_max; i++, dpnt++) 
	if(dpnt->device == SDp) {
	    
	    /* If we are disconnecting a disk driver, sync and invalidate 
	     * everything */
	    max_p = sd_gendisk.max_p;
	    start = i << sd_gendisk.minor_shift;
	    
	    for (i=max_p - 1; i >=0 ; i--) {
		int minor = start+i;
		kdev_t devi = MKDEV(MAJOR_NR, minor);
		sync_dev(devi);
		invalidate_inodes(devi);
		invalidate_buffers(devi);
		sd_gendisk.part[minor].start_sect = 0;
		sd_gendisk.part[minor].nr_sects = 0;
		sd_sizes[minor] = 0;
	    }
	    
	    dpnt->has_part_table = 0;
	    dpnt->device = NULL;
	    dpnt->capacity = 0;
	    SDp->attached--;
	    sd_template.dev_noticed--;
	    sd_template.nr_dev--;
	    sd_gendisk.nr_real--;
	    return;
	}
    return;
}

#ifdef MODULE

int init_module(void) {
    sd_template.usage_count = &mod_use_count_;
    return scsi_register_module(MODULE_SCSI_DEV, &sd_template);
}

void cleanup_module( void) 
{
    struct gendisk * prev_sdgd;
    struct gendisk * sdgd;
    
    scsi_unregister_module(MODULE_SCSI_DEV, &sd_template);
    unregister_blkdev(SCSI_DISK_MAJOR, "sd");
    sd_registered--;
    if( rscsi_disks != NULL )
    {
	scsi_init_free((char *) rscsi_disks,
		       (sd_template.dev_noticed + SD_EXTRA_DEVS) 
		       * sizeof(Scsi_Disk));
	
	scsi_init_free((char *) sd_sizes, sd_template.dev_max * sizeof(int));
	scsi_init_free((char *) sd_blocksizes, sd_template.dev_max * sizeof(int));
	scsi_init_free((char *) sd_hardsizes, sd_template.dev_max * sizeof(int));
	scsi_init_free((char *) sd, 
		       (sd_template.dev_max << 4) * sizeof(struct hd_struct));
	/*
	 * Now remove sd_gendisk from the linked list
	 */
	sdgd = gendisk_head;
	prev_sdgd = NULL;
	while(sdgd != &sd_gendisk)
	{
	    prev_sdgd = sdgd;
	    sdgd = sdgd->next;
	}
	
	if(sdgd != &sd_gendisk)
	    printk("sd_gendisk not in disk chain.\n");
	else {
	    if(prev_sdgd != NULL)
		prev_sdgd->next = sdgd->next;
	    else
		gendisk_head = sdgd->next;
	}
    }
    
    blksize_size[MAJOR_NR] = NULL;
    blk_dev[MAJOR_NR].request_fn = NULL;
    blk_size[MAJOR_NR] = NULL;  
    hardsect_size[MAJOR_NR] = NULL;
    read_ahead[MAJOR_NR] = 0;
    sd_template.dev_max = 0;
}
#endif /* MODULE */

/*
 * Overrides for Emacs so that we almost follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-indent-level: 4
 * c-brace-imaginary-offset: 0
 * c-brace-offset: -4
 * c-argdecl-indent: 4
 * c-label-offset: -4
 * c-continued-statement-offset: 4
 * c-continued-brace-offset: 0
 * indent-tabs-mode: nil
 * tab-width: 8
 * End:
 */