usb.c

底层驱动开发

		 * their inquiry data */
		else if ((us->srb->cmnd[0] == INQUIRY) &&
			    (us->flags & US_FL_FIX_INQUIRY)) {
			unsigned char data_ptr[36] = {
			    0x00, 0x80, 0x02, 0x02,
			    0x1F, 0x00, 0x00, 0x00};

			US_DEBUGP("Faking INQUIRY command\n");
			fill_inquiry_response(us, data_ptr, 36);
			us->srb->result = SAM_STAT_GOOD;
		}

		/* we've got a command, let's do it! */
		else {
			US_DEBUG(usb_stor_show_command(us->srb));
			us->proto_handler(us->srb, us);
		}

		/* lock access to the state */
		scsi_lock(host);

		/* indicate that the command is done */
		if (us->srb->result != DID_ABORT << 16) {
			US_DEBUGP("scsi cmd done, result=0x%x\n", 
				   us->srb->result);
			us->srb->scsi_done(us->srb);
		} else {
SkipForAbort:
			US_DEBUGP("scsi command aborted\n");
		}

		/* If an abort request was received we need to signal that
		 * the abort has finished.  The proper test for this is
		 * the TIMED_OUT flag, not srb->result == DID_ABORT, because
		 * the timeout might have occurred after the command had
		 * already completed with a different result code. */
		if (test_bit(US_FLIDX_TIMED_OUT, &us->flags)) {
			complete(&(us->notify));

			/* Allow USB transfers to resume */
			clear_bit(US_FLIDX_ABORTING, &us->flags);
			clear_bit(US_FLIDX_TIMED_OUT, &us->flags);
		}

		/* finished working on this command */
		us->srb = NULL;
		scsi_unlock(host);

		/* unlock the device pointers */
		up(&(us->dev_semaphore));
	} /* for (;;) */

	scsi_host_put(host);

	/* notify the exit routine that we're actually exiting now 
	 *
	 * complete()/wait_for_completion() is similar to up()/down(),
	 * except that complete() is safe in the case where the structure
	 * is getting deleted in a parallel mode of execution (i.e. just
	 * after the down() -- that's necessary for the thread-shutdown
	 * case.
	 *
	 * complete_and_exit() goes even further than this -- it is safe in
	 * the case that the thread of the caller is going away (not just
	 * the structure) -- this is necessary for the module-remove case.
	 * This is important in preemption kernels, which transfer the flow
	 * of execution immediately upon a complete().
	 */
	complete_and_exit(&threads_gone, 0);
}	

/***********************************************************************
 * Device probing and disconnecting
 ***********************************************************************/

/* Associate our private data with the USB device */
static int associate_dev(struct us_data *us, struct usb_interface *intf)
{
	US_DEBUGP("-- %s\n", __FUNCTION__);

	/* Fill in the device-related fields */
	us->pusb_dev = interface_to_usbdev(intf);
	us->pusb_intf = intf;
	us->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
	US_DEBUGP("Vendor: 0x%04x, Product: 0x%04x, Revision: 0x%04x\n",
			le16_to_cpu(us->pusb_dev->descriptor.idVendor),
			le16_to_cpu(us->pusb_dev->descriptor.idProduct),
			le16_to_cpu(us->pusb_dev->descriptor.bcdDevice));
	US_DEBUGP("Interface Subclass: 0x%02x, Protocol: 0x%02x\n",
			intf->cur_altsetting->desc.bInterfaceSubClass,
			intf->cur_altsetting->desc.bInterfaceProtocol);

	/* Store our private data in the interface */
	usb_set_intfdata(intf, us);

	/* Allocate the device-related DMA-mapped buffers */
	us->cr = usb_buffer_alloc(us->pusb_dev, sizeof(*us->cr),
			GFP_KERNEL, &us->cr_dma);
	if (!us->cr) {
		US_DEBUGP("usb_ctrlrequest allocation failed\n");
		return -ENOMEM;
	}

	us->iobuf = usb_buffer_alloc(us->pusb_dev, US_IOBUF_SIZE,
			GFP_KERNEL, &us->iobuf_dma);
	if (!us->iobuf) {
		US_DEBUGP("I/O buffer allocation failed\n");
		return -ENOMEM;
	}
	return 0;
}

/* Get the unusual_devs entries and the string descriptors */
static void get_device_info(struct us_data *us, int id_index)
{
	struct usb_device *dev = us->pusb_dev;
	struct usb_interface_descriptor *idesc =
		&us->pusb_intf->cur_altsetting->desc;
	struct us_unusual_dev *unusual_dev = &us_unusual_dev_list[id_index];
	struct usb_device_id *id = &storage_usb_ids[id_index];

	/* Store the entries */
	us->unusual_dev = unusual_dev;
	us->subclass = (unusual_dev->useProtocol == US_SC_DEVICE) ?
			idesc->bInterfaceSubClass :
			unusual_dev->useProtocol;
	us->protocol = (unusual_dev->useTransport == US_PR_DEVICE) ?
			idesc->bInterfaceProtocol :
			unusual_dev->useTransport;
	us->flags = unusual_dev->flags;

	/*
	 * This flag is only needed when we're in high-speed, so let's
	 * disable it if we're in full-speed
	 */
	if (dev->speed != USB_SPEED_HIGH)
		us->flags &= ~US_FL_GO_SLOW;

	/* Log a message if a non-generic unusual_dev entry contains an
	 * unnecessary subclass or protocol override.  This may stimulate
	 * reports from users that will help us remove unneeded entries
	 * from the unusual_devs.h table.
	 */
	if (id->idVendor || id->idProduct) {
		static char *msgs[3] = {
			"an unneeded SubClass entry",
			"an unneeded Protocol entry",
			"unneeded SubClass and Protocol entries"};
		struct usb_device_descriptor *ddesc = &dev->descriptor;
		int msg = -1;

		if (unusual_dev->useProtocol != US_SC_DEVICE &&
			us->subclass == idesc->bInterfaceSubClass)
			msg += 1;
		if (unusual_dev->useTransport != US_PR_DEVICE &&
			us->protocol == idesc->bInterfaceProtocol)
			msg += 2;
		if (msg >= 0 && !(unusual_dev->flags & US_FL_NEED_OVERRIDE))
			printk(KERN_NOTICE USB_STORAGE "This device "
				"(%04x,%04x,%04x S %02x P %02x)"
				" has %s in unusual_devs.h\n"
				"   Please send a copy of this message to "
				"<[e-mail]>\n",
				le16_to_cpu(ddesc->idVendor),
				le16_to_cpu(ddesc->idProduct),
				le16_to_cpu(ddesc->bcdDevice),
				idesc->bInterfaceSubClass,
				idesc->bInterfaceProtocol,
				msgs[msg]);
	}
}

/* Get the transport settings */
static int get_transport(struct us_data *us)
{
	switch (us->protocol) {
	case US_PR_CB:
		us->transport_name = "Control/Bulk";
		us->transport = usb_stor_CB_transport;
		us->transport_reset = usb_stor_CB_reset;
		us->max_lun = 7;
		break;

	case US_PR_CBI:
		us->transport_name = "Control/Bulk/Interrupt";
		us->transport = usb_stor_CBI_transport;
		us->transport_reset = usb_stor_CB_reset;
		us->max_lun = 7;
		break;

	case US_PR_BULK:
		us->transport_name = "Bulk";
		us->transport = usb_stor_Bulk_transport;
		us->transport_reset = usb_stor_Bulk_reset;
		break;

#ifdef CONFIG_USB_STORAGE_USBAT
	case US_PR_SCM_ATAPI:
		us->transport_name = "SCM/ATAPI";
		us->transport = usbat_transport;
		us->transport_reset = usb_stor_CB_reset;
		us->max_lun = 1;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_SDDR09
	case US_PR_EUSB_SDDR09:
		us->transport_name = "EUSB/SDDR09";
		us->transport = sddr09_transport;
		us->transport_reset = usb_stor_CB_reset;
		us->max_lun = 0;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_SDDR55
	case US_PR_SDDR55:
		us->transport_name = "SDDR55";
		us->transport = sddr55_transport;
		us->transport_reset = sddr55_reset;
		us->max_lun = 0;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_DPCM
	case US_PR_DPCM_USB:
		us->transport_name = "Control/Bulk-EUSB/SDDR09";
		us->transport = dpcm_transport;
		us->transport_reset = usb_stor_CB_reset;
		us->max_lun = 1;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_FREECOM
	case US_PR_FREECOM:
		us->transport_name = "Freecom";
		us->transport = freecom_transport;
		us->transport_reset = usb_stor_freecom_reset;
		us->max_lun = 0;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_DATAFAB
	case US_PR_DATAFAB:
		us->transport_name  = "Datafab Bulk-Only";
		us->transport = datafab_transport;
		us->transport_reset = usb_stor_Bulk_reset;
		us->max_lun = 1;
		break;
#endif

#ifdef CONFIG_USB_STORAGE_JUMPSHOT
	case US_PR_JUMPSHOT:
		us->transport_name  = "Lexar Jumpshot Control/Bulk";
		us->transport = jumpshot_transport;
		us->transport_reset = usb_stor_Bulk_reset;
		us->max_lun = 1;
		break;
#endif

	default:
		return -EIO;
	}
	US_DEBUGP("Transport: %s\n", us->transport_name);

	/* fix for single-lun devices */
	if (us->flags & US_FL_SINGLE_LUN)
		us->max_lun = 0;
	return 0;
}

/* Get the protocol settings */
static int get_protocol(struct us_data *us)
{
	switch (us->subclass) {
	case US_SC_RBC:
		us->protocol_name = "Reduced Block Commands (RBC)";
		us->proto_handler = usb_stor_transparent_scsi_command;
		break;

	case US_SC_8020:
		us->protocol_name = "8020i";
		us->proto_handler = usb_stor_ATAPI_command;
		us->max_lun = 0;
		break;

	case US_SC_QIC:
		us->protocol_name = "QIC-157";
		us->proto_handler = usb_stor_qic157_command;
		us->max_lun = 0;
		break;

	case US_SC_8070:
		us->protocol_name = "8070i";
		us->proto_handler = usb_stor_ATAPI_command;
		us->max_lun = 0;
		break;

	case US_SC_SCSI:
		us->protocol_name = "Transparent SCSI";
		us->proto_handler = usb_stor_transparent_scsi_command;
		break;

	case US_SC_UFI:
		us->protocol_name = "Uniform Floppy Interface (UFI)";
		us->proto_handler = usb_stor_ufi_command;
		break;

#ifdef CONFIG_USB_STORAGE_ISD200
	case US_SC_ISD200:
		us->protocol_name = "ISD200 ATA/ATAPI";
		us->proto_handler = isd200_ata_command;
		break;
#endif

	default:
		return -EIO;
	}
	US_DEBUGP("Protocol: %s\n", us->protocol_name);
	return 0;
}

/* Get the pipe settings */
static int get_pipes(struct us_data *us)
{
	struct usb_host_interface *altsetting =
		us->pusb_intf->cur_altsetting;
	int i;
	struct usb_endpoint_descriptor *ep;
	struct usb_endpoint_descriptor *ep_in = NULL;
	struct usb_endpoint_descriptor *ep_out = NULL;
	struct usb_endpoint_descriptor *ep_int = NULL;

	/*
	 * Find the endpoints we need.
	 * We are expecting a minimum of 2 endpoints - in and out (bulk).
	 * An optional interrupt is OK (necessary for CBI protocol).
	 * We will ignore any others.
	 */
	for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
		ep = &altsetting->endpoint[i].desc;

		/* Is it a BULK endpoint? */
		if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
				== USB_ENDPOINT_XFER_BULK) {
			/* BULK in or out? */
			if (ep->bEndpointAddress & USB_DIR_IN)
				ep_in = ep;
			else
				ep_out = ep;
		}

		/* Is it an interrupt endpoint? */
		else if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
				== USB_ENDPOINT_XFER_INT) {
			ep_int = ep;
		}
	}

	if (!ep_in || !ep_out || (us->protocol == US_PR_CBI && !ep_int)) {
		US_DEBUGP("Endpoint sanity check failed! Rejecting dev.\n");