i2o_block.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

	*hds  = (unsigned char) heads; 
}


/*
 *	Rescan the partition tables
 */
 
static int do_i2ob_revalidate(kdev_t dev, int maxu)
{
	int minor=MINOR(dev);
	int i;
	
	minor&=0xF0;

	i2ob_dev[minor].refcnt++;
	if(i2ob_dev[minor].refcnt>maxu+1)
	{
		i2ob_dev[minor].refcnt--;
		return -EBUSY;
	}
	
	for( i = 15; i>=0 ; i--)
	{
		int m = minor+i;
		invalidate_device(MKDEV(MAJOR_NR, m), 1);
		i2ob_gendisk.part[m].start_sect = 0;
		i2ob_gendisk.part[m].nr_sects = 0;
	}

	/*
	 *	Do a physical check and then reconfigure
	 */
	 
	i2ob_install_device(i2ob_dev[minor].controller, i2ob_dev[minor].i2odev,
		minor);
	i2ob_dev[minor].refcnt--;
	return 0;
}

/*
 *	Issue device specific ioctl calls.
 */

static int i2ob_ioctl(struct inode *inode, struct file *file,
		     unsigned int cmd, unsigned long arg)
{
	struct i2ob_device *dev;
	int minor;

	/* Anyone capable of this syscall can do *real bad* things */

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (!inode)
		return -EINVAL;
	minor = MINOR(inode->i_rdev);
	if (minor >= (MAX_I2OB<<4))
		return -ENODEV;

	dev = &i2ob_dev[minor];
	switch (cmd) {
		case HDIO_GETGEO:
		{
			struct hd_geometry g;
			int u=minor&0xF0;
			i2o_block_biosparam(i2ob_sizes[u]<<1, 
				&g.cylinders, &g.heads, &g.sectors);
			g.start = i2ob[minor].start_sect;
			return copy_to_user((void *)arg,&g, sizeof(g))?-EFAULT:0;
		}
		
		case BLKI2OGRSTRAT:
			return put_user(dev->rcache, (int *)arg);
		case BLKI2OGWSTRAT:
			return put_user(dev->wcache, (int *)arg);
		case BLKI2OSRSTRAT:
			if(arg<0||arg>CACHE_SMARTFETCH)
				return -EINVAL;
			dev->rcache = arg;
			break;
		case BLKI2OSWSTRAT:
			if(arg!=0 && (arg<CACHE_WRITETHROUGH || arg>CACHE_SMARTBACK))
				return -EINVAL;
			dev->wcache = arg;
			break;
	
		case BLKRRPART:
			if(!capable(CAP_SYS_ADMIN))
				return -EACCES;
			return do_i2ob_revalidate(inode->i_rdev,1);
			
		default:
			return blk_ioctl(inode->i_rdev, cmd, arg);
	}
	return 0;
}

/*
 *	Close the block device down
 */
 
static int i2ob_release(struct inode *inode, struct file *file)
{
	struct i2ob_device *dev;
	int minor;

	minor = MINOR(inode->i_rdev);
	if (minor >= (MAX_I2OB<<4))
		return -ENODEV;
	dev = &i2ob_dev[(minor&0xF0)];

	/*
	 * This is to deail with the case of an application
	 * opening a device and then the device dissapears while
	 * it's in use, and then the application tries to release
	 * it.  ex: Unmounting a deleted RAID volume at reboot. 
	 * If we send messages, it will just cause FAILs since
	 * the TID no longer exists.
	 */
	if(!dev->i2odev)
		return 0;

	if (dev->refcnt <= 0)
		printk(KERN_ALERT "i2ob_release: refcount(%d) <= 0\n", dev->refcnt);
	dev->refcnt--;
	if(dev->refcnt==0)
	{
		/*
		 *	Flush the onboard cache on unmount
		 */
		u32 msg[5];
		int *query_done = &dev->done_flag;
		msg[0] = (FIVE_WORD_MSG_SIZE|SGL_OFFSET_0);
		msg[1] = I2O_CMD_BLOCK_CFLUSH<<24|HOST_TID<<12|dev->tid;
		msg[2] = i2ob_context|0x40000000;
		msg[3] = (u32)query_done;
		msg[4] = 60<<16;
		DEBUG("Flushing...");
		i2o_post_wait(dev->controller, msg, 20, 60);

		/*
		 *	Unlock the media
		 */
		msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
		msg[1] = I2O_CMD_BLOCK_MUNLOCK<<24|HOST_TID<<12|dev->tid;
		msg[2] = i2ob_context|0x40000000;
		msg[3] = (u32)query_done;
		msg[4] = -1;
		DEBUG("Unlocking...");
		i2o_post_wait(dev->controller, msg, 20, 2);
		DEBUG("Unlocked.\n");

		msg[0] = FOUR_WORD_MSG_SIZE|SGL_OFFSET_0;
		msg[1] = I2O_CMD_BLOCK_POWER<<24 | HOST_TID << 12 | dev->tid;
		if(dev->flags & (1<<3|1<<4))	/* Removable */
			msg[4] = 0x21 << 24;
		else
			msg[4] = 0x24 << 24;

		if(i2o_post_wait(dev->controller, msg, 20, 60)==0)
			dev->power = 0x24;

		/*
 		 * Now unclaim the device.
		 */

		if (i2o_release_device(dev->i2odev, &i2o_block_handler))
			printk(KERN_ERR "i2ob_release: controller rejected unclaim.\n");
		
		DEBUG("Unclaim\n");
	}
	return 0;
}

/*
 *	Open the block device.
 */
 
static int i2ob_open(struct inode *inode, struct file *file)
{
	int minor;
	struct i2ob_device *dev;
	
	if (!inode)
		return -EINVAL;
	minor = MINOR(inode->i_rdev);
	if (minor >= MAX_I2OB<<4)
		return -ENODEV;
	dev=&i2ob_dev[(minor&0xF0)];

	if(!dev->i2odev)	
		return -ENODEV;
	
	if(dev->refcnt++==0)
	{ 
		u32 msg[6];
		
		DEBUG("Claim ");
		if(i2o_claim_device(dev->i2odev, &i2o_block_handler))
		{
			dev->refcnt--;
			printk(KERN_INFO "I2O Block: Could not open device\n");
			return -EBUSY;
		}
		DEBUG("Claimed ");
		/*
	 	 *	Power up if needed
	 	 */

		if(dev->power > 0x1f)
		{
			msg[0] = FOUR_WORD_MSG_SIZE|SGL_OFFSET_0;
			msg[1] = I2O_CMD_BLOCK_POWER<<24 | HOST_TID << 12 | dev->tid;
			msg[4] = 0x02 << 24;
			if(i2o_post_wait(dev->controller, msg, 20, 60) == 0)
				dev->power = 0x02;
		}

		/*
		 *	Mount the media if needed. Note that we don't use
		 *	the lock bit. Since we have to issue a lock if it
		 *	refuses a mount (quite possible) then we might as
		 *	well just send two messages out.
		 */
		msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;		
		msg[1] = I2O_CMD_BLOCK_MMOUNT<<24|HOST_TID<<12|dev->tid;
		msg[4] = -1;
		msg[5] = 0;
		DEBUG("Mount ");
		i2o_post_wait(dev->controller, msg, 24, 2);

		/*
		 *	Lock the media
		 */
		msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
		msg[1] = I2O_CMD_BLOCK_MLOCK<<24|HOST_TID<<12|dev->tid;
		msg[4] = -1;
		DEBUG("Lock ");
		i2o_post_wait(dev->controller, msg, 20, 2);
		DEBUG("Ready.\n");
	}		
	return 0;
}

/*
 *	Issue a device query
 */
 
static int i2ob_query_device(struct i2ob_device *dev, int table, 
	int field, void *buf, int buflen)
{
	return i2o_query_scalar(dev->controller, dev->tid,
		table, field, buf, buflen);
}


/*
 *	Install the I2O block device we found.
 */
 
static int i2ob_install_device(struct i2o_controller *c, struct i2o_device *d, int unit)
{
	u64 size;
	u32 blocksize;
	u8 type;
	u16 power;
	u32 flags, status;
	struct i2ob_device *dev=&i2ob_dev[unit];
	int i;

	/*
	 * For logging purposes...
	 */
	printk(KERN_INFO "i2ob: Installing tid %d device at unit %d\n", 
			d->lct_data.tid, unit);	

	/*
	 *	Ask for the current media data. If that isn't supported
	 *	then we ask for the device capacity data
	 */
	if(i2ob_query_device(dev, 0x0004, 1, &blocksize, 4) != 0
	  || i2ob_query_device(dev, 0x0004, 0, &size, 8) !=0 )
	{
		i2ob_query_device(dev, 0x0000, 3, &blocksize, 4);
		i2ob_query_device(dev, 0x0000, 4, &size, 8);
	}
	
	if(i2ob_query_device(dev, 0x0000, 2, &power, 2)!=0)
		power = 0;
	i2ob_query_device(dev, 0x0000, 5, &flags, 4);
	i2ob_query_device(dev, 0x0000, 6, &status, 4);
	i2ob_sizes[unit] = (int)(size>>10);
	for(i=unit; i <= unit+15 ; i++)
		i2ob_hardsizes[i] = blocksize;
	i2ob_gendisk.part[unit].nr_sects = size>>9;
	i2ob[unit].nr_sects = (int)(size>>9);

	/*
	 * Max number of Scatter-Gather Elements
	 */	

	i2ob_dev[unit].power = power;	/* Save power state in device proper */
	i2ob_dev[unit].flags = flags;

	for(i=unit;i<=unit+15;i++)
	{
		i2ob_dev[i].power = power;	/* Save power state */
		i2ob_dev[unit].flags = flags;	/* Keep the type info */
		i2ob_max_sectors[i] = 96;	/* 256 might be nicer but many controllers 
						   explode on 65536 or higher */
		i2ob_dev[i].max_segments = (d->controller->status_block->inbound_frame_size - 7) / 2;
		
		i2ob_dev[i].rcache = CACHE_SMARTFETCH;
		i2ob_dev[i].wcache = CACHE_WRITETHROUGH;
		
		if(d->controller->battery == 0)
			i2ob_dev[i].wcache = CACHE_WRITETHROUGH;

		if(d->controller->type == I2O_TYPE_PCI && d->controller->bus.pci.promise)
			i2ob_dev[i].wcache = CACHE_WRITETHROUGH;

		if(d->controller->type == I2O_TYPE_PCI && d->controller->bus.pci.short_req)
		{
			i2ob_max_sectors[i] = 8;
			i2ob_dev[i].max_segments = 8;
		}
	}

	sprintf(d->dev_name, "%s%c", i2ob_gendisk.major_name, 'a' + (unit>>4));

	printk(KERN_INFO "%s: Max segments %d, queue depth %d, byte limit %d.\n",
		 d->dev_name, i2ob_dev[unit].max_segments, i2ob_dev[unit].depth, i2ob_max_sectors[unit]<<9);

	i2ob_query_device(dev, 0x0000, 0, &type, 1);

	printk(KERN_INFO "%s: ", d->dev_name);
	switch(type)
	{
		case 0: printk("Disk Storage");break;
		case 4: printk("WORM");break;
		case 5: printk("CD-ROM");break;
		case 7:	printk("Optical device");break;
		default:
			printk("Type %d", type);
	}
	if(status&(1<<10))
		printk("(RAID)");

	if((flags^status)&(1<<4|1<<3))	/* Missing media or device */
	{
		printk(KERN_INFO " Not loaded.\n");
		/* Device missing ? */
		if((flags^status)&(1<<4))
			return 1;
	}
	else
	{
		printk(": %dMB, %d byte sectors",
			(int)(size>>20), blocksize);
	}
	if(status&(1<<0))
	{
		u32 cachesize;
		i2ob_query_device(dev, 0x0003, 0, &cachesize, 4);
		cachesize>>=10;
		if(cachesize>4095)
			printk(", %dMb cache", cachesize>>10);
		else
			printk(", %dKb cache", cachesize);
	}
	printk(".\n");
	printk(KERN_INFO "%s: Maximum sectors/read set to %d.\n", 
		d->dev_name, i2ob_max_sectors[unit]);

	/* 
	 * If this is the first I2O block device found on this IOP,
	 * we need to initialize all the queue data structures
	 * before any I/O can be performed. If it fails, this
	 * device is useless.
	 */
	if(!i2ob_queues[c->unit]) {
		if(i2ob_init_iop(c->unit))
			return 1;
	}

	/* 
	 * This will save one level of lookup/indirection in critical 
	 * code so that we can directly get the queue ptr from the
	 * device instead of having to go the IOP data structure.
	 */
	dev->req_queue = &i2ob_queues[c->unit]->req_queue;

	grok_partitions(&i2ob_gendisk, unit>>4, 1<<4, (long)(size>>9));

	/*
	 * Register for the events we're interested in and that the
	 * device actually supports.
	 */
	i2o_event_register(c, d->lct_data.tid, i2ob_context, unit, 
		(I2OB_EVENT_MASK & d->lct_data.event_capabilities));

	return 0;
}

/*
 * Initialize IOP specific queue structures.  This is called
 * once for each IOP that has a block device sitting behind it.
 */
static int i2ob_init_iop(unsigned int unit)
{
	int i;

	i2ob_queues[unit] = (struct i2ob_iop_queue *) kmalloc(sizeof(struct i2ob_iop_queue), GFP_ATOMIC);
	if(!i2ob_queues[unit])
	{
		printk(KERN_WARNING "Could not allocate request queue for I2O block device!\n");
		return -1;
	}

	for(i = 0; i< MAX_I2OB_DEPTH; i++)
	{
		i2ob_queues[unit]->request_queue[i].next =  &i2ob_queues[unit]->request_queue[i+1];
		i2ob_queues[unit]->request_queue[i].num = i;
	}
	
	/* Queue is MAX_I2OB + 1... */
	i2ob_queues[unit]->request_queue[i].next = NULL;
	i2ob_queues[unit]->i2ob_qhead = &i2ob_queues[unit]->request_queue[0];
	atomic_set(&i2ob_queues[unit]->queue_depth, 0);

	blk_init_queue(&i2ob_queues[unit]->req_queue, i2ob_request);
	blk_queue_headactive(&i2ob_queues[unit]->req_queue, 0);
	i2ob_queues[unit]->req_queue.back_merge_fn = i2ob_back_merge;
	i2ob_queues[unit]->req_queue.front_merge_fn = i2ob_front_merge;
	i2ob_queues[unit]->req_queue.merge_requests_fn = i2ob_merge_requests;
	i2ob_queues[unit]->req_queue.queuedata = &i2ob_queues[unit];

	return 0;
}

/*
 * Get the request queue for the given device.
 */	
static request_queue_t* i2ob_get_queue(kdev_t dev)
{
	int unit = MINOR(dev)&0xF0;
	return i2ob_dev[unit].req_queue;
}

/*
 * Probe the I2O subsytem for block class devices
 */
static void i2ob_scan(int bios)
{
	int i;
	int warned = 0;

	struct i2o_device *d, *b=NULL;
	struct i2o_controller *c;
	struct i2ob_device *dev;
		
	for(i=0; i< MAX_I2O_CONTROLLERS; i++)
	{
		c=i2o_find_controller(i);
	
		if(c==NULL)
			continue;

		/*
		 *    The device list connected to the I2O Controller is doubly linked
		 * Here we traverse the end of the list , and start claiming devices
		 * from that end. This assures that within an I2O controller atleast
		 * the newly created volumes get claimed after the older ones, thus
		 * mapping to same major/minor (and hence device file name) after 
		 * every reboot.
		 * The exception being: 
		 * 1. If there was a TID reuse.
		 * 2. There was more than one I2O controller. 
		 */

		if(!bios)
		{
			for (d=c->devices;d!=NULL;d=d->next)
			if(d->next == NULL)