sd.c

Linux Kernel 2.6.9 for OMAP1710

	
	if (!longrc) {
		sector_size = (buffer[4] << 24) |
			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
		if (buffer[0] == 0xff && buffer[1] == 0xff &&
		    buffer[2] == 0xff && buffer[3] == 0xff) {
			if(sizeof(sdkp->capacity) > 4) {
				printk(KERN_NOTICE "%s : very big device. try to use"
				       " READ CAPACITY(16).\n", diskname);
				longrc = 1;
				goto repeat;
			} else {
				printk(KERN_ERR "%s: too big for kernel.  Assuming maximum 2Tb\n", diskname);
			}
		}
		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
			(buffer[1] << 16) |
			(buffer[2] << 8) |
			buffer[3]);			
	} else {
		sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
			((u64)buffer[1] << 48) |
			((u64)buffer[2] << 40) |
			((u64)buffer[3] << 32) |
			((sector_t)buffer[4] << 24) |
			((sector_t)buffer[5] << 16) |
			((sector_t)buffer[6] << 8)  |
			(sector_t)buffer[7]);
			
		sector_size = (buffer[8] << 24) |
			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
	}	

got_data:
	if (sector_size == 0) {
		sector_size = 512;
		printk(KERN_NOTICE "%s : sector size 0 reported, "
		       "assuming 512.\n", diskname);
	}

	if (sector_size != 512 &&
	    sector_size != 1024 &&
	    sector_size != 2048 &&
	    sector_size != 4096 &&
	    sector_size != 256) {
		printk(KERN_NOTICE "%s : unsupported sector size "
		       "%d.\n", diskname, sector_size);
		/*
		 * The user might want to re-format the drive with
		 * a supported sectorsize.  Once this happens, it
		 * would be relatively trivial to set the thing up.
		 * For this reason, we leave the thing in the table.
		 */
		sdkp->capacity = 0;
	}
	{
		/*
		 * The msdos fs needs to know the hardware sector size
		 * So I have created this table. See ll_rw_blk.c
		 * Jacques Gelinas ([e-mail])
		 */
		int hard_sector = sector_size;
		sector_t sz = sdkp->capacity * (hard_sector/256);
		request_queue_t *queue = sdp->request_queue;
		sector_t mb;

		blk_queue_hardsect_size(queue, hard_sector);
		/* avoid 64-bit division on 32-bit platforms */
		mb = sz >> 1;
		sector_div(sz, 1250);
		mb -= sz - 974;
		sector_div(mb, 1950);

		printk(KERN_NOTICE "SCSI device %s: "
		       "%llu %d-byte hdwr sectors (%llu MB)\n",
		       diskname, (unsigned long long)sdkp->capacity,
		       hard_sector, (unsigned long long)mb);
	}

	/* Rescale capacity to 512-byte units */
	if (sector_size == 4096)
		sdkp->capacity <<= 3;
	else if (sector_size == 2048)
		sdkp->capacity <<= 2;
	else if (sector_size == 1024)
		sdkp->capacity <<= 1;
	else if (sector_size == 256)
		sdkp->capacity >>= 1;

	sdkp->device->sector_size = sector_size;
}

/* called with buffer of length 512 */
static inline int
sd_do_mode_sense(struct scsi_request *SRpnt, int dbd, int modepage,
		 unsigned char *buffer, int len, struct scsi_mode_data *data)
{
	return __scsi_mode_sense(SRpnt, dbd, modepage, buffer, len,
				 SD_TIMEOUT, SD_MAX_RETRIES, data);
}

/*
 * read write protect setting, if possible - called only in sd_revalidate_disk()
 * called with buffer of length 512
 */
static void
sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
		   struct scsi_request *SRpnt, unsigned char *buffer) {
	int res;
	struct scsi_mode_data data;

	set_disk_ro(sdkp->disk, 0);
	if (sdkp->device->skip_ms_page_3f) {
		printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
		return;
	}

	if (sdkp->device->use_192_bytes_for_3f) {
		res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 192, &data);
	} else {
		/*
		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
		 * We have to start carefully: some devices hang if we ask
		 * for more than is available.
		 */
		res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 4, &data);

		/*
		 * Second attempt: ask for page 0 When only page 0 is
		 * implemented, a request for page 3F may return Sense Key
		 * 5: Illegal Request, Sense Code 24: Invalid field in
		 * CDB.
		 */
		if (!scsi_status_is_good(res))
			res = sd_do_mode_sense(SRpnt, 0, 0, buffer, 4, &data);

		/*
		 * Third attempt: ask 255 bytes, as we did earlier.
		 */
		if (!scsi_status_is_good(res))
			res = sd_do_mode_sense(SRpnt, 0, 0x3F, buffer, 255,
					       &data);
	}

	if (!scsi_status_is_good(res)) {
		printk(KERN_WARNING
		       "%s: test WP failed, assume Write Enabled\n", diskname);
	} else {
		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
		set_disk_ro(sdkp->disk, sdkp->write_prot);
		printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname,
		       sdkp->write_prot ? "on" : "off");
		printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n",
		       diskname, buffer[0], buffer[1], buffer[2], buffer[3]);
	}
}

/*
 * sd_read_cache_type - called only from sd_revalidate_disk()
 * called with buffer of length 512
 */
static void
sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
		   struct scsi_request *SRpnt, unsigned char *buffer) {
	int len = 0, res;

	const int dbd = 0;	   /* DBD */
	const int modepage = 0x08; /* current values, cache page */
	struct scsi_mode_data data;

	if (sdkp->device->skip_ms_page_8)
		goto defaults;

	/* cautiously ask */
	res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, 4, &data);

	if (!scsi_status_is_good(res))
		goto bad_sense;

	/* that went OK, now ask for the proper length */
	len = data.length;

	/*
	 * We're only interested in the first three bytes, actually.
	 * But the data cache page is defined for the first 20.
	 */
	if (len < 3)
		goto bad_sense;
	if (len > 20)
		len = 20;

	/* Take headers and block descriptors into account */
	len += data.header_length + data.block_descriptor_length;

	/* Get the data */
	res = sd_do_mode_sense(SRpnt, dbd, modepage, buffer, len, &data);

	if (scsi_status_is_good(res)) {
		const char *types[] = {
			"write through", "none", "write back",
			"write back, no read (daft)"
		};
		int ct = 0;
		int offset = data.header_length +
			data.block_descriptor_length + 2;

		sdkp->WCE = ((buffer[offset] & 0x04) != 0);
		sdkp->RCD = ((buffer[offset] & 0x01) != 0);

		ct =  sdkp->RCD + 2*sdkp->WCE;

		printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
		       diskname, types[ct]);

		return;
	}

bad_sense:
	if ((SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
	     && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
	     /* ASC 0x24 ASCQ 0x00: Invalid field in CDB */
	     && SRpnt->sr_sense_buffer[12] == 0x24
	     && SRpnt->sr_sense_buffer[13] == 0x00) {
		printk(KERN_NOTICE "%s: cache data unavailable\n",
		       diskname);
	} else {
		printk(KERN_ERR "%s: asking for cache data failed\n",
		       diskname);
	}

defaults:
	printk(KERN_ERR "%s: assuming drive cache: write through\n",
	       diskname);
	sdkp->WCE = 0;
	sdkp->RCD = 0;
}

/**
 *	sd_revalidate_disk - called the first time a new disk is seen,
 *	performs disk spin up, read_capacity, etc.
 *	@disk: struct gendisk we care about
 **/
static int sd_revalidate_disk(struct gendisk *disk)
{
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdp = sdkp->device;
	struct scsi_request *sreq;
	unsigned char *buffer;

	SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));

	/*
	 * If the device is offline, don't try and read capacity or any
	 * of the other niceties.
	 */
	if (!scsi_device_online(sdp))
		goto out;

	sreq = scsi_allocate_request(sdp, GFP_KERNEL);
	if (!sreq) {
		printk(KERN_WARNING "(sd_revalidate_disk:) Request allocation "
		       "failure.\n");
		goto out;
	}

	buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA);
	if (!buffer) {
		printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
		       "failure.\n");
		goto out_release_request;
	}

	/* defaults, until the device tells us otherwise */
	sdp->sector_size = 512;
	sdkp->capacity = 0;
	sdkp->media_present = 1;
	sdkp->write_prot = 0;
	sdkp->WCE = 0;
	sdkp->RCD = 0;

	sd_spinup_disk(sdkp, disk->disk_name, sreq, buffer);

	/*
	 * Without media there is no reason to ask; moreover, some devices
	 * react badly if we do.
	 */
	if (sdkp->media_present) {
		sd_read_capacity(sdkp, disk->disk_name, sreq, buffer);
		if (sdp->removable)
			sd_read_write_protect_flag(sdkp, disk->disk_name,
					sreq, buffer);
		sd_read_cache_type(sdkp, disk->disk_name, sreq, buffer);
	}
		
	set_capacity(disk, sdkp->capacity);
	kfree(buffer);

 out_release_request: 
	scsi_release_request(sreq);
 out:
	return 0;
}

/**
 *	sd_probe - called during driver initialization and whenever a
 *	new scsi device is attached to the system. It is called once
 *	for each scsi device (not just disks) present.
 *	@dev: pointer to device object
 *
 *	Returns 0 if successful (or not interested in this scsi device 
 *	(e.g. scanner)); 1 when there is an error.
 *
 *	Note: this function is invoked from the scsi mid-level.
 *	This function sets up the mapping between a given 
 *	<host,channel,id,lun> (found in sdp) and new device name 
 *	(e.g. /dev/sda). More precisely it is the block device major 
 *	and minor number that is chosen here.
 *
 *	Assume sd_attach is not re-entrant (for time being)
 *	Also think about sd_attach() and sd_remove() running coincidentally.
 **/
static int sd_probe(struct device *dev)
{
	struct scsi_device *sdp = to_scsi_device(dev);
	struct scsi_disk *sdkp;
	struct gendisk *gd;
	u32 index;
	int error;

	error = -ENODEV;
	if ((sdp->type != TYPE_DISK) && (sdp->type != TYPE_MOD))
		goto out;

	SCSI_LOG_HLQUEUE(3, printk("sd_attach: scsi device: <%d,%d,%d,%d>\n", 
			 sdp->host->host_no, sdp->channel, sdp->id, sdp->lun));

	error = -ENOMEM;
	sdkp = kmalloc(sizeof(*sdkp), GFP_KERNEL);
	if (!sdkp)
		goto out;

	memset (sdkp, 0, sizeof(*sdkp));
	kref_init(&sdkp->kref);

	gd = alloc_disk(16);
	if (!gd)
		goto out_free;

	if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))
		goto out_put;

	spin_lock(&sd_index_lock);
	error = idr_get_new(&sd_index_idr, NULL, &index);
	spin_unlock(&sd_index_lock);

	if (index >= SD_MAX_DISKS)
		error = -EBUSY;
	if (error)
		goto out_put;

	sdkp->device = sdp;
	sdkp->driver = &sd_template;
	sdkp->disk = gd;
	sdkp->index = index;
	sdkp->openers = 0;

	if (!sdp->timeout) {
		if (sdp->type == TYPE_DISK)
			sdp->timeout = SD_TIMEOUT;
		else
			sdp->timeout = SD_MOD_TIMEOUT;
	}

	gd->major = sd_major((index & 0xf0) >> 4);
	gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
	gd->minors = 16;
	gd->fops = &sd_fops;

	if (index < 26) {
		sprintf(gd->disk_name, "sd%c", 'a' + index % 26);
	} else if (index < (26 + 1) * 26) {
		sprintf(gd->disk_name, "sd%c%c",
			'a' + index / 26 - 1,'a' + index % 26);
	} else {
		const unsigned int m1 = (index / 26 - 1) / 26 - 1;
		const unsigned int m2 = (index / 26 - 1) % 26;
		const unsigned int m3 =  index % 26;
		sprintf(gd->disk_name, "sd%c%c%c",
			'a' + m1, 'a' + m2, 'a' + m3);
	}

	strcpy(gd->devfs_name, sdp->devfs_name);

	gd->private_data = &sdkp->driver;

	sd_revalidate_disk(gd);

	gd->driverfs_dev = &sdp->sdev_gendev;
	gd->flags = GENHD_FL_DRIVERFS;
	if (sdp->removable)
		gd->flags |= GENHD_FL_REMOVABLE;
	gd->queue = sdkp->device->request_queue;

	dev_set_drvdata(dev, sdkp);
	add_disk(gd);

	printk(KERN_NOTICE "Attached scsi %sdisk %s at scsi%d, channel %d, "
	       "id %d, lun %d\n", sdp->removable ? "removable " : "",
	       gd->disk_name, sdp->host->host_no, sdp->channel,
	       sdp->id, sdp->lun);

	return 0;

out_put:
	put_disk(gd);
out_free:
	kfree(sdkp);
out:
	return error;
}

/**
 *	sd_remove - called whenever a scsi disk (previously recognized by
 *	sd_probe) is detached from the system. It is called (potentially
 *	multiple times) during sd module unload.
 *	@sdp: pointer to mid level scsi device object
 *
 *	Note: this function is invoked from the scsi mid-level.
 *	This function potentially frees up a device name (e.g. /dev/sdc)
 *	that could be re-used by a subsequent sd_probe().
 *	This function is not called when the built-in sd driver is "exit-ed".
 **/
static int sd_remove(struct device *dev)
{
	struct scsi_disk *sdkp = dev_get_drvdata(dev);

	del_gendisk(sdkp->disk);
	sd_shutdown(dev);
	down(&sd_ref_sem);
	kref_put(&sdkp->kref, scsi_disk_release);
	up(&sd_ref_sem);

	return 0;
}

/**
 *	scsi_disk_release - Called to free the scsi_disk structure
 *	@kref: pointer to embedded kref
 *
 *	sd_ref_sem must be held entering this routine.  Because it is
 *	called on last put, you should always use the scsi_disk_get()
 *	scsi_disk_put() helpers which manipulate the semaphore directly
 *	and never do a direct kref_put().
 **/
static void scsi_disk_release(struct kref *kref)
{
	struct scsi_disk *sdkp = to_scsi_disk(kref);
	struct gendisk *disk = sdkp->disk;
	
	spin_lock(&sd_index_lock);
	idr_remove(&sd_index_idr, sdkp->index);
	spin_unlock(&sd_index_lock);

	disk->private_data = NULL;

	put_disk(disk);

	kfree(sdkp);
}

/*
 * Send a SYNCHRONIZE CACHE instruction down to the device through
 * the normal SCSI command structure.  Wait for the command to
 * complete.
 */
static void sd_shutdown(struct device *dev)
{
	struct scsi_device *sdp = to_scsi_device(dev);
	struct scsi_disk *sdkp = dev_get_drvdata(dev);

	if (!sdkp)
		return;         /* this can happen */

	if (!sdkp->WCE)
		return;

	printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
			sdkp->disk->disk_name);
	sd_sync_cache(sdp);
}	

/**
 *	init_sd - entry point for this driver (both when built in or when
 *	a module).
 *
 *	Note: this function registers this driver with the scsi mid-level.
 **/
static int __init init_sd(void)
{
	int majors = 0, i;

	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));

	for (i = 0; i < SD_MAJORS; i++)
		if (register_blkdev(sd_major(i), "sd") == 0)
			majors++;

	if (!majors)
		return -ENODEV;

	return scsi_register_driver(&sd_template.gendrv);
}

/**
 *	exit_sd - exit point for this driver (when it is a module).
 *
 *	Note: this function unregisters this driver from the scsi mid-level.
 **/
static void __exit exit_sd(void)
{
	int i;

	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));

	scsi_unregister_driver(&sd_template.gendrv);
	for (i = 0; i < SD_MAJORS; i++)
		unregister_blkdev(sd_major(i), "sd");
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eric Youngdale");
MODULE_DESCRIPTION("SCSI disk (sd) driver");

module_init(init_sd);
module_exit(exit_sd);