text: /* Driver for USB Mass Storage compliant devices
   * SCSI layer glue code
   *
   * Current development and maintenance by:
   *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   *
   * Developed with the assistance of:
   *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
   *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
   *
   * Initial work by:
   *   (c) 1999 Michael Gee (michael@linuxspecific.com)
   *
   * This driver is based on the 'USB Mass Storage Class' document. This
   * describes in detail the protocol used to communicate with such
   * devices.  Clearly, the designers had SCSI and ATAPI commands in
   * mind when they created this document.  The commands are all very
   * similar to commands in the SCSI-II and ATAPI specifications.
   *
   * It is important to note that in a number of cases this class
   * exhibits class-specific exemptions from the USB specification.
   * Notably the usage of NAK, STALL and ACK differs from the norm, in
   * that they are used to communicate wait, failed and OK on commands.
   *
   * Also, for certain devices, the interrupt endpoint is used to convey
   * status of a command.
   *
   * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
   * information about this driver.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the
   * Free Software Foundation; either version 2, or (at your option) any
   * later version.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License along
   * with this program; if not, write to the Free Software Foundation, Inc.,
   * 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/module.h>
  #include <linux/mutex.h>
  
  #include <scsi/scsi.h>
  #include <scsi/scsi_cmnd.h>
  #include <scsi/scsi_devinfo.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_eh.h>
  
  #include "usb.h"
  #include "scsiglue.h"
  #include "debug.h"
  #include "transport.h"
  #include "protocol.h"
  
  /* Vendor IDs for companies that seem to include the READ CAPACITY bug
   * in all their devices
   */
  #define VENDOR_ID_NOKIA		0x0421
  #define VENDOR_ID_NIKON		0x04b0
  #define VENDOR_ID_PENTAX	0x0a17
  #define VENDOR_ID_MOTOROLA	0x22b8
  
  /***********************************************************************
   * Host functions 
   ***********************************************************************/
  
  static const char* host_info(struct Scsi_Host *host)
  {
  	struct us_data *us = host_to_us(host);
  	return us->scsi_name;
  }
  
  static int slave_alloc (struct scsi_device *sdev)
  {
  	/*
  	 * Set the INQUIRY transfer length to 36.  We don't use any of
  	 * the extra data and many devices choke if asked for more or
  	 * less than 36 bytes.
  	 */
  	sdev->inquiry_len = 36;
  
  	/* USB has unusual DMA-alignment requirements: Although the
  	 * starting address of each scatter-gather element doesn't matter,
  	 * the length of each element except the last must be divisible
  	 * by the Bulk maxpacket value.  There's currently no way to
  	 * express this by block-layer constraints, so we'll cop out
  	 * and simply require addresses to be aligned at 512-byte
  	 * boundaries.  This is okay since most block I/O involves
  	 * hardware sectors that are multiples of 512 bytes in length,
  	 * and since host controllers up through USB 2.0 have maxpacket
  	 * values no larger than 512.
  	 *
  	 * But it doesn't suffice for Wireless USB, where Bulk maxpacket
  	 * values can be as large as 2048.  To make that work properly
  	 * will require changes to the block layer.
  	 */
  	blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
  
  	return 0;
  }
  
  static int slave_configure(struct scsi_device *sdev)
  {
  	struct us_data *us = host_to_us(sdev->host);
  
  	/* Many devices have trouble transferring more than 32KB at a time,
  	 * while others have trouble with more than 64K. At this time we
  	 * are limiting both to 32K (64 sectores).
  	 */
  	if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
  		unsigned int max_sectors = 64;
  
  		if (us->fflags & US_FL_MAX_SECTORS_MIN)
  			max_sectors = PAGE_CACHE_SIZE >> 9;
  		if (queue_max_hw_sectors(sdev->request_queue) > max_sectors)
  			blk_queue_max_hw_sectors(sdev->request_queue,
  					      max_sectors);
  	} else if (sdev->type == TYPE_TAPE) {
  		/* Tapes need much higher max_sector limits, so just
  		 * raise it to the maximum possible (4 GB / 512) and
  		 * let the queue segment size sort out the real limit.
  		 */
  		blk_queue_max_hw_sectors(sdev->request_queue, 0x7FFFFF);
  	}
  
  	/* Some USB host controllers can't do DMA; they have to use PIO.
  	 * They indicate this by setting their dma_mask to NULL.  For
  	 * such controllers we need to make sure the block layer sets
  	 * up bounce buffers in addressable memory.
  	 */
  	if (!us->pusb_dev->bus->controller->dma_mask)
  		blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_HIGH);
  
  	/* We can't put these settings in slave_alloc() because that gets
  	 * called before the device type is known.  Consequently these
  	 * settings can't be overridden via the scsi devinfo mechanism. */
  	if (sdev->type == TYPE_DISK) {
  
  		/* Some vendors seem to put the READ CAPACITY bug into
  		 * all their devices -- primarily makers of cell phones
  		 * and digital cameras.  Since these devices always use
  		 * flash media and can be expected to have an even number
  		 * of sectors, we will always enable the CAPACITY_HEURISTICS
  		 * flag unless told otherwise. */
  		switch (le16_to_cpu(us->pusb_dev->descriptor.idVendor)) {
  		case VENDOR_ID_NOKIA:
  		case VENDOR_ID_NIKON:
  		case VENDOR_ID_PENTAX:
  		case VENDOR_ID_MOTOROLA:
  			if (!(us->fflags & (US_FL_FIX_CAPACITY |
  					US_FL_CAPACITY_OK)))
  				us->fflags |= US_FL_CAPACITY_HEURISTICS;
  			break;
  		}
  
  		/* Disk-type devices use MODE SENSE(6) if the protocol
  		 * (SubClass) is Transparent SCSI, otherwise they use
  		 * MODE SENSE(10). */
  		if (us->subclass != USB_SC_SCSI && us->subclass != USB_SC_CYP_ATACB)
  			sdev->use_10_for_ms = 1;
  
  		/* Many disks only accept MODE SENSE transfer lengths of
  		 * 192 bytes (that's what Windows uses). */
  		sdev->use_192_bytes_for_3f = 1;
  
  		/* Some devices don't like MODE SENSE with page=0x3f,
  		 * which is the command used for checking if a device
  		 * is write-protected.  Now that we tell the sd driver
  		 * to do a 192-byte transfer with this command the
  		 * majority of devices work fine, but a few still can't
  		 * handle it.  The sd driver will simply assume those
  		 * devices are write-enabled. */
  		if (us->fflags & US_FL_NO_WP_DETECT)
  			sdev->skip_ms_page_3f = 1;
  
  		/* A number of devices have problems with MODE SENSE for
  		 * page x08, so we will skip it. */
  		sdev->skip_ms_page_8 = 1;
  
  		/* Some devices don't handle VPD pages correctly */
  		sdev->skip_vpd_pages = 1;
  
  		/* Some disks return the total number of blocks in response
  		 * to READ CAPACITY rather than the highest block number.
  		 * If this device makes that mistake, tell the sd driver. */
  		if (us->fflags & US_FL_FIX_CAPACITY)
  			sdev->fix_capacity = 1;
  
  		/* A few disks have two indistinguishable version, one of
  		 * which reports the correct capacity and the other does not.
  		 * The sd driver has to guess which is the case. */
  		if (us->fflags & US_FL_CAPACITY_HEURISTICS)
  			sdev->guess_capacity = 1;
  
  		/* Some devices cannot handle READ_CAPACITY_16 */
  		if (us->fflags & US_FL_NO_READ_CAPACITY_16)
  			sdev->no_read_capacity_16 = 1;
  
  		/* assume SPC3 or latter devices support sense size > 18 */
  		if (sdev->scsi_level > SCSI_SPC_2)
  			us->fflags |= US_FL_SANE_SENSE;
  
  		/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
  		 * Hardware Error) when any low-level error occurs,
  		 * recoverable or not.  Setting this flag tells the SCSI
  		 * midlayer to retry such commands, which frequently will
  		 * succeed and fix the error.  The worst this can lead to
  		 * is an occasional series of retries that will all fail. */
  		sdev->retry_hwerror = 1;
  
  		/* USB disks should allow restart.  Some drives spin down
  		 * automatically, requiring a START-STOP UNIT command. */
  		sdev->allow_restart = 1;
  
  		/* Some USB cardreaders have trouble reading an sdcard's last
  		 * sector in a larger then 1 sector read, since the performance
  		 * impact is negible we set this flag for all USB disks */
  		sdev->last_sector_bug = 1;
  
  		/* Enable last-sector hacks for single-target devices using
  		 * the Bulk-only transport, unless we already know the
  		 * capacity will be decremented or is correct. */
  		if (!(us->fflags & (US_FL_FIX_CAPACITY | US_FL_CAPACITY_OK |
  					US_FL_SCM_MULT_TARG)) &&
  				us->protocol == USB_PR_BULK)
  			us->use_last_sector_hacks = 1;
  
  		if (us->sdev_autosuspend_delay >= 0) {
  			sdev->use_rpm_auto = 1;
  			sdev->autosuspend_delay = us->sdev_autosuspend_delay;
  		}
  	} else {
  
  		/* Non-disk-type devices don't need to blacklist any pages
  		 * or to force 192-byte transfer lengths for MODE SENSE.
  		 * But they do need to use MODE SENSE(10). */
  		sdev->use_10_for_ms = 1;
  
  		/* Some (fake) usb cdrom devices don't like READ_DISC_INFO */
  		if (us->fflags & US_FL_NO_READ_DISC_INFO)
  			sdev->no_read_disc_info = 1;
  	}
  
  	/* The CB and CBI transports have no way to pass LUN values
  	 * other than the bits in the second byte of a CDB.  But those
  	 * bits don't get set to the LUN value if the device reports
  	 * scsi_level == 0 (UNKNOWN).  Hence such devices must necessarily
  	 * be single-LUN.
  	 */
  	if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_CBI) &&
  			sdev->scsi_level == SCSI_UNKNOWN)
  		us->max_lun = 0;
  
  	/* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
  	 * REMOVAL command, so suppress those commands. */
  	if (us->fflags & US_FL_NOT_LOCKABLE)
  		sdev->lockable = 0;
  
  	/* this is to satisfy the compiler, tho I don't think the 
  	 * return code is ever checked anywhere. */
  	return 0;
  }
  
  static int target_alloc(struct scsi_target *starget)
  {
  	struct us_data *us = host_to_us(dev_to_shost(starget->dev.parent));
  
  	/*
  	 * Some USB drives don't support REPORT LUNS, even though they
  	 * report a SCSI revision level above 2.  Tell the SCSI layer
  	 * not to issue that command; it will perform a normal sequential
  	 * scan instead.
  	 */
  	starget->no_report_luns = 1;
  
  	/*
  	 * The UFI spec treats the Peripheral Qualifier bits in an
  	 * INQUIRY result as reserved and requires devices to set them
  	 * to 0.  However the SCSI spec requires these bits to be set
  	 * to 3 to indicate when a LUN is not present.
  	 *
  	 * Let the scanning code know if this target merely sets
  	 * Peripheral Device Type to 0x1f to indicate no LUN.
  	 */
  	if (us->subclass == USB_SC_UFI)
  		starget->pdt_1f_for_no_lun = 1;
  
  	return 0;
  }
  
  /* queue a command */
  /* This is always called with scsi_lock(host) held */
  static int queuecommand_lck(struct scsi_cmnd *srb,
  			void (*done)(struct scsi_cmnd *))
  {
  	struct us_data *us = host_to_us(srb->device->host);
  
  	US_DEBUGP("%s called\n", __func__);
  
  	/* check for state-transition errors */
  	if (us->srb != NULL) {
  		printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
  			__func__, us->srb);
  		return SCSI_MLQUEUE_HOST_BUSY;
  	}
  
  	/* fail the command if we are disconnecting */
  	if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
  		US_DEBUGP("Fail command during disconnect\n");
  		srb->result = DID_NO_CONNECT << 16;
  		done(srb);
  		return 0;
  	}
  
  	/* enqueue the command and wake up the control thread */
  	srb->scsi_done = done;
  	us->srb = srb;
  	complete(&us->cmnd_ready);
  
  	return 0;
  }
  
  static DEF_SCSI_QCMD(queuecommand)
  
  /***********************************************************************
   * Error handling functions
   ***********************************************************************/
  
  /* Command timeout and abort */
  static int command_abort(struct scsi_cmnd *srb)
  {
  	struct us_data *us = host_to_us(srb->device->host);
  
  	US_DEBUGP("%s called\n", __func__);
  
  	/* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
  	 * bits are protected by the host lock. */
  	scsi_lock(us_to_host(us));
  
  	/* Is this command still active? */
  	if (us->srb != srb) {
  		scsi_unlock(us_to_host(us));
  		US_DEBUGP ("-- nothing to abort\n");
  		return FAILED;
  	}
  
  	/* Set the TIMED_OUT bit.  Also set the ABORTING bit, but only if
  	 * a device reset isn't already in progress (to avoid interfering
  	 * with the reset).  Note that we must retain the host lock while
  	 * calling usb_stor_stop_transport(); otherwise it might interfere
  	 * with an auto-reset that begins as soon as we release the lock. */
  	set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
  	if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
  		set_bit(US_FLIDX_ABORTING, &us->dflags);
  		usb_stor_stop_transport(us);
  	}
  	scsi_unlock(us_to_host(us));
  
  	/* Wait for the aborted command to finish */
  	wait_for_completion(&us->notify);
  	return SUCCESS;
  }
  
  /* This invokes the transport reset mechanism to reset the state of the
   * device */
  static int device_reset(struct scsi_cmnd *srb)
  {
  	struct us_data *us = host_to_us(srb->device->host);
  	int result;
  
  	US_DEBUGP("%s called\n", __func__);
  
  	/* lock the device pointers and do the reset */
  	mutex_lock(&(us->dev_mutex));
  	result = us->transport_reset(us);
  	mutex_unlock(&us->dev_mutex);
  
  	return result < 0 ? FAILED : SUCCESS;
  }
  
  /* Simulate a SCSI bus reset by resetting the device's USB port. */
  static int bus_reset(struct scsi_cmnd *srb)
  {
  	struct us_data *us = host_to_us(srb->device->host);
  	int result;
  
  	US_DEBUGP("%s called\n", __func__);
  	result = usb_stor_port_reset(us);
  	return result < 0 ? FAILED : SUCCESS;
  }
  
  /* Report a driver-initiated device reset to the SCSI layer.
   * Calling this for a SCSI-initiated reset is unnecessary but harmless.
   * The caller must own the SCSI host lock. */
  void usb_stor_report_device_reset(struct us_data *us)
  {
  	int i;
  	struct Scsi_Host *host = us_to_host(us);
  
  	scsi_report_device_reset(host, 0, 0);
  	if (us->fflags & US_FL_SCM_MULT_TARG) {
  		for (i = 1; i < host->max_id; ++i)
  			scsi_report_device_reset(host, 0, i);
  	}
  }
  
  /* Report a driver-initiated bus reset to the SCSI layer.
   * Calling this for a SCSI-initiated reset is unnecessary but harmless.
   * The caller must not own the SCSI host lock. */
  void usb_stor_report_bus_reset(struct us_data *us)
  {
  	struct Scsi_Host *host = us_to_host(us);
  
  	scsi_lock(host);
  	scsi_report_bus_reset(host, 0);
  	scsi_unlock(host);
  }
  
  /***********************************************************************
   * /proc/scsi/ functions
   ***********************************************************************/
  
  /* we use this macro to help us write into the buffer */
  #undef SPRINTF
  #define SPRINTF(args...) \
  	do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
  
  static int proc_info (struct Scsi_Host *host, char *buffer,
  		char **start, off_t offset, int length, int inout)
  {
  	struct us_data *us = host_to_us(host);
  	char *pos = buffer;
  	const char *string;
  
  	/* if someone is sending us data, just throw it away */
  	if (inout)
  		return length;
  
  	/* print the controller name */
  	SPRINTF("   Host scsi%d: usb-storage\n", host->host_no);
  
  	/* print product, vendor, and serial number strings */
  	if (us->pusb_dev->manufacturer)
  		string = us->pusb_dev->manufacturer;
  	else if (us->unusual_dev->vendorName)
  		string = us->unusual_dev->vendorName;
  	else
  		string = "Unknown";
  	SPRINTF("       Vendor: %s\n", string);
  	if (us->pusb_dev->product)
  		string = us->pusb_dev->product;
  	else if (us->unusual_dev->productName)
  		string = us->unusual_dev->productName;
  	else
  		string = "Unknown";
  	SPRINTF("      Product: %s\n", string);
  	if (us->pusb_dev->serial)
  		string = us->pusb_dev->serial;
  	else
  		string = "None";
  	SPRINTF("Serial Number: %s\n", string);
  
  	/* show the protocol and transport */
  	SPRINTF("     Protocol: %s\n", us->protocol_name);
  	SPRINTF("    Transport: %s\n", us->transport_name);
  
  	/* show the device flags */
  	if (pos < buffer + length) {
  		pos += sprintf(pos, "       Quirks:");
  
  #define US_FLAG(name, value) \
  	if (us->fflags & value) pos += sprintf(pos, " " #name);
  US_DO_ALL_FLAGS
  #undef US_FLAG
  
  		*(pos++) = '\n';
  	}
  
  	/*
  	 * Calculate start of next buffer, and return value.
  	 */
  	*start = buffer + offset;
  
  	if ((pos - buffer) < offset)
  		return (0);
  	else if ((pos - buffer - offset) < length)
  		return (pos - buffer - offset);
  	else
  		return (length);
  }
  
  /***********************************************************************
   * Sysfs interface
   ***********************************************************************/
  
  /* Output routine for the sysfs max_sectors file */
  static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  
  	return sprintf(buf, "%u\n", queue_max_hw_sectors(sdev->request_queue));
  }
  
  /* Input routine for the sysfs max_sectors file */
  static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
  		size_t count)
  {
  	struct scsi_device *sdev = to_scsi_device(dev);
  	unsigned short ms;
  
  	if (sscanf(buf, "%hu", &ms) > 0) {
  		blk_queue_max_hw_sectors(sdev->request_queue, ms);
  		return count;
  	}
  	return -EINVAL;	
  }
  
  static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
  		store_max_sectors);
  
  static struct device_attribute *sysfs_device_attr_list[] = {
  		&dev_attr_max_sectors,
  		NULL,
  		};
  
  /*
   * this defines our host template, with which we'll allocate hosts
   */
  
  struct scsi_host_template usb_stor_host_template = {
  	/* basic userland interface stuff */
  	.name =				"usb-storage",
  	.proc_name =			"usb-storage",
  	.proc_info =			proc_info,
  	.info =				host_info,
  
  	/* command interface -- queued only */
  	.queuecommand =			queuecommand,
  
  	/* error and abort handlers */
  	.eh_abort_handler =		command_abort,
  	.eh_device_reset_handler =	device_reset,
  	.eh_bus_reset_handler =		bus_reset,
  
  	/* queue commands only, only one command per LUN */
  	.can_queue =			1,
  	.cmd_per_lun =			1,
  
  	/* unknown initiator id */
  	.this_id =			-1,
  
  	.slave_alloc =			slave_alloc,
  	.slave_configure =		slave_configure,
  	.target_alloc =			target_alloc,
  
  	/* lots of sg segments can be handled */
  	.sg_tablesize =			SCSI_MAX_SG_CHAIN_SEGMENTS,
  
  	/* limit the total size of a transfer to 120 KB */
  	.max_sectors =                  240,
  
  	/* merge commands... this seems to help performance, but
  	 * periodically someone should test to see which setting is more
  	 * optimal.
  	 */
  	.use_clustering =		1,
  
  	/* emulated HBA */
  	.emulated =			1,
  
  	/* we do our own delay after a device or bus reset */
  	.skip_settle_delay =		1,
  
  	/* sysfs device attributes */
  	.sdev_attrs =			sysfs_device_attr_list,
  
  	/* module management */
  	.module =			THIS_MODULE
  };
  
  /* To Report "Illegal Request: Invalid Field in CDB */
  unsigned char usb_stor_sense_invalidCDB[18] = {
  	[0]	= 0x70,			    /* current error */
  	[2]	= ILLEGAL_REQUEST,	    /* Illegal Request = 0x05 */
  	[7]	= 0x0a,			    /* additional length */
  	[12]	= 0x24			    /* Invalid Field in CDB */
  };
  EXPORT_SYMBOL_GPL(usb_stor_sense_invalidCDB);
  