usb.c

LINUX下USB驱动程序的开发

				us->srb = NULL;
				break;
			}

			if (us->srb->lun > us->max_lun) {
				US_DEBUGP("Bad LUN (%d/%d)\n",
					  us->srb->target, us->srb->lun);
				us->srb->result = DID_BAD_TARGET << 16;

				set_current_state(TASK_INTERRUPTIBLE);
				us->srb->scsi_done(us->srb);
				us->srb = NULL;
				break;
			}

			/* lock the device pointers */
			down(&(us->dev_semaphore));

			/* our device has gone - pretend not ready */
			if (!us->pusb_dev) {
				US_DEBUGP("Request is for removed device\n");
				/* For REQUEST_SENSE, it's the data.  But
				 * for anything else, it should look like
				 * we auto-sensed for it.
				 */
				if (us->srb->cmnd[0] == REQUEST_SENSE) {
					memcpy(us->srb->request_buffer, 
					       usb_stor_sense_notready, 
					       sizeof(usb_stor_sense_notready));
					us->srb->result = GOOD << 1;
				} else if(us->srb->cmnd[0] == INQUIRY) {
					unsigned char data_ptr[36] = {
					    0x20, 0x80, 0x02, 0x02,
					    0x1F, 0x00, 0x00, 0x00};
					US_DEBUGP("Faking INQUIRY command for disconnected device\n");
					fill_inquiry_response(us, data_ptr, 36);
					us->srb->result = GOOD << 1;
				} else {
					memcpy(us->srb->sense_buffer, 
					       usb_stor_sense_notready, 
					       sizeof(usb_stor_sense_notready));
					us->srb->result = CHECK_CONDITION << 1;
				}
			} else { /* !us->pusb_dev */

				/* Handle those devices which need us to fake 
				 * their inquiry data */
				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 = GOOD << 1;
				} else {
					/* we've got a command, let's do it! */
					US_DEBUG(usb_stor_show_command(us->srb));
					us->proto_handler(us->srb, us);
				}
			}

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

			/* 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);
				set_current_state(TASK_INTERRUPTIBLE);
				us->srb->scsi_done(us->srb);
			};
			if (atomic_read(&us->abortcnt) != 0) {			
				US_DEBUGP("scsi command aborted\n");
				set_current_state(TASK_INTERRUPTIBLE);
				complete(&(us->notify));
			}
			us->srb = NULL;
			break;

		case US_ACT_DEVICE_RESET:
			break;

		case US_ACT_BUS_RESET:
			break;

		case US_ACT_HOST_RESET:
			break;

		} /* end switch on action */

		/* exit if we get a signal to exit */
		if (action == US_ACT_EXIT) {
			US_DEBUGP("-- US_ACT_EXIT command received\n");
			break;
		}
	} /* for (;;) */

	/* clean up after ourselves */
	set_current_state(TASK_INTERRUPTIBLE);

	/* notify the exit routine that we're actually exiting now */
	complete(&(us->notify));

	return 0;
}	

/* Set up the IRQ pipe and handler
 * Note that this function assumes that all the data in the us_data
 * strucuture is current.  This includes the ep_int field, which gives us
 * the endpoint for the interrupt.
 * Returns non-zero on failure, zero on success
 *
 * ss->dev_semaphore is expected taken, except for a newly minted,
 * unregistered device.
 */ 
static int usb_stor_allocate_irq(struct us_data *ss)
{
	unsigned int pipe;
	int maxp;
	int result;

	US_DEBUGP("Allocating IRQ for CBI transport\n");

	/* allocate the URB */
	ss->irq_urb = usb_alloc_urb(0);
	if (!ss->irq_urb) {
		US_DEBUGP("couldn't allocate interrupt URB");
		return 1;
	}

	/* calculate the pipe and max packet size */
	pipe = usb_rcvintpipe(ss->pusb_dev, ss->ep_int->bEndpointAddress & 
			      USB_ENDPOINT_NUMBER_MASK);
	maxp = usb_maxpacket(ss->pusb_dev, pipe, usb_pipeout(pipe));
	if (maxp > sizeof(ss->irqbuf))
		maxp = sizeof(ss->irqbuf);

	/* fill in the URB with our data */
	FILL_INT_URB(ss->irq_urb, ss->pusb_dev, pipe, ss->irqbuf, maxp, 
		     usb_stor_CBI_irq, ss, ss->ep_int->bInterval); 

	/* submit the URB for processing */
	result = usb_submit_urb(ss->irq_urb);
	US_DEBUGP("usb_submit_urb() returns %d\n", result);
	if (result) {
		usb_free_urb(ss->irq_urb);
		return 2;
	}

	return 0;
}

/* Probe to see if a new device is actually a SCSI device */
static void * storage_probe(struct usb_device *dev, unsigned int ifnum,
			    const struct usb_device_id *id)
{
	int i;
	const int id_index = id - storage_usb_ids; 
	char mf[USB_STOR_STRING_LEN];		     /* manufacturer */
	char prod[USB_STOR_STRING_LEN];		     /* product */
	char serial[USB_STOR_STRING_LEN];	     /* serial number */
	GUID(guid);			   /* Global Unique Identifier */
	unsigned int flags;
	struct us_unusual_dev *unusual_dev;
	struct us_data *ss = NULL;
#ifdef CONFIG_USB_STORAGE_SDDR09
	int result;
#endif

	/* these are temporary copies -- we test on these, then put them
	 * in the us-data structure 
	 */
	struct usb_endpoint_descriptor *ep_in = NULL;
	struct usb_endpoint_descriptor *ep_out = NULL;
	struct usb_endpoint_descriptor *ep_int = NULL;
	u8 subclass = 0;
	u8 protocol = 0;

	/* the altsettting on the interface we're probing that matched our
	 * usb_match_id table
	 */
	struct usb_interface *intf = dev->actconfig->interface;
	struct usb_interface_descriptor *altsetting =
		intf[ifnum].altsetting + intf[ifnum].act_altsetting;
	US_DEBUGP("act_altsettting is %d\n", intf[ifnum].act_altsetting);

	/* clear the temporary strings */
	memset(mf, 0, sizeof(mf));
	memset(prod, 0, sizeof(prod));
	memset(serial, 0, sizeof(serial));

	/* 
	 * Can we support this device, either because we know about it
	 * from our unusual device list, or because it advertises that it's
	 * compliant to the specification?
	 *
	 * id_index is calculated in the declaration to be the index number
	 * of the match from the usb_device_id table, so we can find the
	 * corresponding entry in the private table.
	 */
	US_DEBUGP("id_index calculated to be: %d\n", id_index);
	US_DEBUGP("Array length appears to be: %d\n", sizeof(us_unusual_dev_list) / sizeof(us_unusual_dev_list[0]));
	if (id_index <
	    sizeof(us_unusual_dev_list) / sizeof(us_unusual_dev_list[0])) {
		unusual_dev = &us_unusual_dev_list[id_index];
		if (unusual_dev->vendorName)
			US_DEBUGP("Vendor: %s\n", unusual_dev->vendorName);
		if (unusual_dev->productName)
			US_DEBUGP("Product: %s\n", unusual_dev->productName);
	} else
		/* no, we can't support it */
		return NULL;

	/* At this point, we know we've got a live one */
	US_DEBUGP("USB Mass Storage device detected\n");

	/* Determine subclass and protocol, or copy from the interface */
	subclass = (unusual_dev->useProtocol == US_SC_DEVICE) ?
			altsetting->bInterfaceSubClass :
			unusual_dev->useProtocol;
	protocol = (unusual_dev->useTransport == US_PR_DEVICE) ?
			altsetting->bInterfaceProtocol :
			unusual_dev->useTransport;
	flags = unusual_dev->flags;

	/*
	 * 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->bNumEndpoints; i++) {
		/* is it an BULK endpoint? */
		if ((altsetting->endpoint[i].bmAttributes & 
		     USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_BULK) {
			/* BULK in or out? */
			if (altsetting->endpoint[i].bEndpointAddress & 
			    USB_DIR_IN)
				ep_in = &altsetting->endpoint[i];
			else
				ep_out = &altsetting->endpoint[i];
		}

		/* is it an interrupt endpoint? */
		if ((altsetting->endpoint[i].bmAttributes & 
		     USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT) {
			ep_int = &altsetting->endpoint[i];
		}
	}
	US_DEBUGP("Endpoints: In: 0x%p Out: 0x%p Int: 0x%p (Period %d)\n",
		  ep_in, ep_out, ep_int, ep_int ? ep_int->bInterval : 0);

#ifdef CONFIG_USB_STORAGE_SDDR09
	if (protocol == US_PR_EUSB_SDDR09 || protocol == US_PR_DPCM_USB) {
		/* set the configuration -- STALL is an acceptable response here */
		result = usb_set_configuration(dev, 1);

		US_DEBUGP("Result from usb_set_configuration is %d\n", result);
		if (result == -EPIPE) {
			US_DEBUGP("-- clearing stall on control interface\n");
			usb_clear_halt(dev, usb_sndctrlpipe(dev, 0));
		} else if (result != 0) {
			/* it's not a stall, but another error -- time to bail */
			US_DEBUGP("-- Unknown error.  Rejecting device\n");
			return NULL;
		}
	}
#endif

	/* Do some basic sanity checks, and bail if we find a problem */
	if (!ep_in || !ep_out || (protocol == US_PR_CBI && !ep_int)) {
		US_DEBUGP("Endpoint sanity check failed! Rejecting dev.\n");
		return NULL;
	}

	/* At this point, we're committed to using the device */
	usb_inc_dev_use(dev);

	/* clear the GUID and fetch the strings */
	GUID_CLEAR(guid);
	if (dev->descriptor.iManufacturer)
		usb_string(dev, dev->descriptor.iManufacturer, 
			   mf, sizeof(mf));
	if (dev->descriptor.iProduct)
		usb_string(dev, dev->descriptor.iProduct, 
			   prod, sizeof(prod));
	if (dev->descriptor.iSerialNumber && !(flags & US_FL_IGNORE_SER))
		usb_string(dev, dev->descriptor.iSerialNumber, 
			   serial, sizeof(serial));

	/* Create a GUID for this device */
	if (dev->descriptor.iSerialNumber && serial[0]) {
		/* If we have a serial number, and it's a non-NULL string */
		make_guid(guid, dev->descriptor.idVendor, 
			  dev->descriptor.idProduct, serial);
	} else {
		/* We don't have a serial number, so we use 0 */
		make_guid(guid, dev->descriptor.idVendor, 
			  dev->descriptor.idProduct, "0");
	}

	/*
	 * Now check if we have seen this GUID before
	 * We're looking for a device with a matching GUID that isn't
	 * already on the system
	 */
	ss = us_list;
	while ((ss != NULL) && 
	       ((ss->pusb_dev) || !GUID_EQUAL(guid, ss->guid)))
		ss = ss->next;

	if (ss != NULL) {
		/* Existing device -- re-connect */
		US_DEBUGP("Found existing GUID " GUID_FORMAT "\n",
			  GUID_ARGS(guid));

		/* lock the device pointers */
		down(&(ss->dev_semaphore));

		/* establish the connection to the new device upon reconnect */
		ss->ifnum = ifnum;
		ss->pusb_dev = dev;

		/* copy over the endpoint data */
		if (ep_in)
			ss->ep_in = ep_in->bEndpointAddress & 
				USB_ENDPOINT_NUMBER_MASK;
		if (ep_out)
			ss->ep_out = ep_out->bEndpointAddress & 
				USB_ENDPOINT_NUMBER_MASK;
		ss->ep_int = ep_int;

		/* allocate an IRQ callback if one is needed */
		if ((ss->protocol == US_PR_CBI) && usb_stor_allocate_irq(ss)) {
			up(&(ss->dev_semaphore));
			usb_dec_dev_use(dev);
			return NULL;
		}

		/* allocate the URB we're going to use */
		ss->current_urb = usb_alloc_urb(0);
		if (!ss->current_urb) {
			up(&(ss->dev_semaphore));
			usb_dec_dev_use(dev);
			return NULL;
		}

                /* Re-Initialize the device if it needs it */
		if (unusual_dev && unusual_dev->initFunction)
			(unusual_dev->initFunction)(ss);

		/* unlock the device pointers */
		up(&(ss->dev_semaphore));

	} else { 
		/* New device -- allocate memory and initialize */
		US_DEBUGP("New GUID " GUID_FORMAT "\n", GUID_ARGS(guid));

		if ((ss = (struct us_data *)kmalloc(sizeof(struct us_data), 
						    GFP_KERNEL)) == NULL) {
			printk(KERN_WARNING USB_STORAGE "Out of memory\n");
			usb_dec_dev_use(dev);
			return NULL;
		}
		memset(ss, 0, sizeof(struct us_data));

		/* allocate the URB we're going to use */
		ss->current_urb = usb_alloc_urb(0);
		if (!ss->current_urb) {
			kfree(ss);
			usb_dec_dev_use(dev);
			return NULL;
		}

		/* Initialize the mutexes only when the struct is new */
		init_completion(&(ss->notify));
		init_MUTEX_LOCKED(&(ss->ip_waitq));
		spin_lock_init(&(ss->queue_exclusion));
		init_MUTEX(&(ss->current_urb_sem));
		init_MUTEX(&(ss->dev_semaphore));

		/* copy over the subclass and protocol data */
		ss->subclass = subclass;
		ss->protocol = protocol;
		ss->flags = flags;
		ss->unusual_dev = unusual_dev;

		/* copy over the endpoint data */