inode.c

LINUX2.4.18内核下的usb GADGET驱动程序

			value = min (ctrl->wLength, (u16) sizeof *dev->dev);
			req->buf = dev->dev;
			break;
#ifdef	HIGHSPEED
		case USB_DT_DEVICE_QUALIFIER:
			if (!dev->hs_config)
				break;
			value = min (ctrl->wLength, (u16)
				sizeof (struct usb_qualifier_descriptor));
			make_qualifier (dev);
			break;
		case USB_DT_OTHER_SPEED_CONFIG:
			// FALLTHROUGH
#endif
		case USB_DT_CONFIG:
			value = config_buf (dev,
					ctrl->wValue >> 8,
					ctrl->wValue & 0xff);
			if (value >= 0)
				value = min (ctrl->wLength, (u16) value);
			break;
		case USB_DT_STRING:
			goto unrecognized;

		default:		// all others are errors
			break;
		}
		break;

	/* currently one config, two speeds */
	case USB_REQ_SET_CONFIGURATION:
		if (ctrl->bRequestType != 0)
			break;
		if (0 == (u8) ctrl->wValue) {
			value = 0;
			dev->current_config = 0;
			// user mode expected to disable endpoints
		} else {
			u8	config;
#ifdef	HIGHSPEED
			if (gadget->speed == USB_SPEED_HIGH)
				config = dev->hs_config->bConfigurationValue;
			else
#endif
				config = dev->config->bConfigurationValue;

			if (config == (u8) ctrl->wValue) {
				value = 0;
				dev->current_config = config;
			}
		}

		/* report SET_CONFIGURATION like any other control request,
		 * except that usermode may not stall this.  the next
		 * request mustn't be allowed start until this finishes:
		 * endpoints and threads set up, etc.
		 *
		 * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
		 * has bad/racey automagic that prevents synchronizing here.
		 * even kernel mode drivers often miss them.
		 */
		if (value == 0) {
			INFO (dev, "configuration #%d\n", dev->current_config);
			if (dev->usermode_setup) {
				dev->setup_can_stall = 0;
				goto delegate;
			}
		}
		break;

#ifndef	CONFIG_USB_GADGETFS_PXA2XX
	/* PXA automagically handles this request too */
	case USB_REQ_GET_CONFIGURATION:
		if (ctrl->bRequestType != 0x80)
			break;
		*(u8 *)req->buf = dev->current_config;
		value = min (ctrl->wLength, (u16) 1);
		break;
#endif

	default:
unrecognized:
		VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
			dev->usermode_setup ? "delegate" : "fail",
			ctrl->bRequestType, ctrl->bRequest,
			ctrl->wValue, ctrl->wIndex, ctrl->wLength);

		/* if there's an ep0 reader, don't stall */
		if (dev->usermode_setup) {
			dev->setup_can_stall = 1;
delegate:
			dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
						? 1 : 0;
			dev->setup_out_ready = 0;
			dev->setup_out_error = 0;
			value = 0;

			/* read DATA stage for OUT right away */
			if (unlikely (!dev->setup_in && ctrl->wLength)) {
				value = setup_req (gadget->ep0, dev->req,
							ctrl->wLength);
				if (value < 0)
					break;
				value = usb_ep_queue (gadget->ep0, dev->req,
							GFP_ATOMIC);
				if (value < 0) {
					clean_req (gadget->ep0, dev->req);
					break;
				}

				/* we can't currently stall these */
				dev->setup_can_stall = 0;
			}

			/* state changes when reader collects event */
			event = next_event (dev, GADGETFS_SETUP);
			event->u.setup = *ctrl;
			ep0_readable (dev);
			spin_unlock (&dev->lock);
			return 0;
		}
	}

	/* proceed with data transfer and status phases? */
	if (value >= 0 && dev->state != STATE_SETUP) {
		req->length = value;
		value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
		if (value < 0) {
			DBG (dev, "ep_queue --> %d\n", value);
			req->status = 0;
		}
	}

	/* device stalls when value < 0 */
	spin_unlock (&dev->lock);
	return value;
}

static void destroy_ep_files (struct dev_data *dev)
{
	struct list_head	*entry, *tmp;

	DBG (dev, "%s %d\n", __FUNCTION__, dev->state);

	/* dev->state must prevent interference */
restart:
	spin_lock_irq (&dev->lock);
	list_for_each_safe (entry, tmp, &dev->epfiles) {
		struct ep_data	*ep;

		/* break link to FS */
		ep = list_entry (entry, struct ep_data, epfiles);
		list_del_init (&ep->epfiles);

		/* break link to controller */
		if (ep->state == STATE_EP_ENABLED)
			(void) usb_ep_disable (ep->ep);
		ep->state = STATE_EP_UNBOUND;
		usb_ep_free_request (ep->ep, ep->req);
		ep->ep = 0;
		wake_up (&ep->wait);
		put_ep (ep);

		spin_unlock_irq (&dev->lock);

		/* fds may still be open */
		goto restart;
	}
	spin_unlock_irq (&dev->lock);
}


static int activate_ep_files (struct dev_data *dev)
{
	struct usb_ep	*ep;

	gadget_for_each_ep (ep, dev->gadget) {
		struct ep_data	*data;

		data = kmalloc (sizeof *data, GFP_KERNEL);
		if (!data)
			goto enomem;
		memset (data, 0, sizeof data);
		data->state = STATE_EP_DISABLED;
		init_MUTEX (&data->lock);
		init_waitqueue_head (&data->wait);

		strncpy (data->name, ep->name, sizeof (data->name) - 1);
		atomic_set (&data->count, 1);
		data->dev = dev;
		get_dev (dev);

		data->ep = ep;
		ep->driver_data = data;

		data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
		if (!data->req)
			goto enomem;

		list_add_tail (&data->epfiles, &dev->epfiles);
	}
	return 0;

enomem:
	DBG (dev, "%s enomem\n", __FUNCTION__);
	destroy_ep_files (dev);
	return -ENOMEM;
}

static void
gadgetfs_unbind (struct usb_gadget *gadget)
{
	struct dev_data		*dev = get_gadget_data (gadget);

	DBG (dev, "%s\n", __FUNCTION__);

	spin_lock_irq (&dev->lock);
	dev->state = STATE_DEV_UNBOUND;
	spin_unlock_irq (&dev->lock);

	destroy_ep_files (dev);
	gadget->ep0->driver_data = 0;
	set_gadget_data (gadget, 0);

	/* we've already been disconnected ... no i/o is active */
	if (dev->req)
		usb_ep_free_request (gadget->ep0, dev->req);
	DBG (dev, "%s done\n", __FUNCTION__);
	put_dev (dev);
}

static struct dev_data		*the_device;

static int
gadgetfs_bind (struct usb_gadget *gadget)
{
	struct dev_data		*dev = the_device;

	if (!dev)
		return -ESRCH;
	if (0 != strcmp (CHIP, gadget->name)) {
		printk (KERN_ERR "%s expected " CHIP " controller not %s\n",
			shortname, gadget->name);
		return -ENODEV;
	}

	set_gadget_data (gadget, dev);
	dev->gadget = gadget;
	gadget->ep0->driver_data = dev;
	dev->dev->bMaxPacketSize0 = gadget->ep0->maxpacket;

	/* preallocate control response and buffer */
	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
	if (!dev->req)
		goto enomem;
	dev->req->context = 0;
	dev->req->complete = epio_complete;

	if (activate_ep_files (dev) < 0)
		goto enomem;

	INFO (dev, "bound to %s driver\n", gadget->name);
	dev->state = STATE_UNCONNECTED;
	get_dev (dev);
	return 0;

enomem:
	gadgetfs_unbind (gadget);
	return -ENOMEM;
}

static void
gadgetfs_disconnect (struct usb_gadget *gadget)
{
	struct dev_data		*dev = get_gadget_data (gadget);

	if (dev->state == STATE_UNCONNECTED) {
		DBG (dev, "already unconnected\n");
		return;
	}
	dev->state = STATE_UNCONNECTED;

	INFO (dev, "disconnected\n");
	spin_lock (&dev->lock);
	next_event (dev, GADGETFS_DISCONNECT);
	ep0_readable (dev);
	spin_unlock (&dev->lock);
}

static void
gadgetfs_suspend (struct usb_gadget *gadget)
{
	struct dev_data		*dev = get_gadget_data (gadget);

	INFO (dev, "suspended from state %d\n", dev->state);
	spin_lock (&dev->lock);
	switch (dev->state) {
	case STATE_SETUP:		// VERY odd... host died??
	case STATE_CONNECTED:
	case STATE_UNCONNECTED:
		next_event (dev, GADGETFS_SUSPEND);
		ep0_readable (dev);
		/* FALLTHROUGH */
	default:
		break;
	}
	spin_unlock (&dev->lock);
}

static struct usb_gadget_driver gadgetfs_driver = {
#ifdef	HIGHSPEED
	.speed		= USB_SPEED_HIGH,
#else
	.speed		= USB_SPEED_FULL,
#endif
	.function	= (char *) driver_desc,
	.bind		= gadgetfs_bind,
	.unbind		= gadgetfs_unbind,
	.setup		= gadgetfs_setup,
	.disconnect	= gadgetfs_disconnect,
	.suspend	= gadgetfs_suspend,

	.driver 	= {
		.name		= (char *) shortname,
		// .shutdown = ...
		// .suspend = ...
		// .resume = ...
	},
};

/*----------------------------------------------------------------------*/

/* DEVICE INITIALIZATION
 *
 *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
 *     status = write (fd, descriptors, sizeof descriptors)
 *
 * That write establishes the device configuration, so the kernel can
 * bind to the controller ... guaranteeing it can handle enumeration
 * at all necessary speeds.  Descriptor order is:
 *
 * . message tag (u32, host order) ... for now, must be zero; it
 *	would change to support features like multi-config devices
 * . full/low speed config ... all wTotalLength bytes (with interface,
 *	class, altsetting, endpoint, and other descriptors)
 * . high speed config ... all descriptors, for high speed operation;
 * 	this one's optional except for high-speed hardware
 * . device descriptor
 *
 * Endpoints are not yet enabled. Drivers may want to immediately
 * initialize them, using the /dev/gadget/ep* files that are available
 * as soon as the kernel sees the configuration, or they can wait
 * until device configuration and interface altsetting changes create
 * the need to configure (or unconfigure) them.
 *
 * After initialization, the device stays active for as long as that
 * $CHIP file is open.  Events may then be read from that descriptor,
 * such configuration notifications.  More complex drivers will handle
 * some control requests in user space.
 */

static int is_valid_config (struct usb_config_descriptor *config)
{
	return config->bDescriptorType == USB_DT_CONFIG
		&& config->bLength == USB_DT_CONFIG_SIZE
		&& config->bConfigurationValue != 0
		&& (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
		&& (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
	/* FIXME check lengths: walk to end */
}

static ssize_t
dev_config (struct file *fd, const char *buf, size_t len, loff_t *ptr)
{
	struct dev_data		*dev = fd->private_data;
	ssize_t			value = len, length = len;
	unsigned		total;
	u32			tag;
	char			*kbuf;

	if (dev->state != STATE_OPENED)
		return -EEXIST;

	if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
		return -EINVAL;

	/* we might need to change message format someday */
	if (copy_from_user (&tag, buf, 4))
		return -EFAULT;
	if (tag != 0)
		return -EINVAL;
	buf += 4;
	length -= 4;

	kbuf = kmalloc (length, SLAB_KERNEL);
	if (!kbuf)
		return -ENOMEM;
	if (copy_from_user (kbuf, buf, length)) {
		kfree (kbuf);
		return -EFAULT;
	}

	spin_lock_irq (&dev->lock);
	value = -EINVAL;
	if (dev->buf)
		goto fail;
	dev->buf = kbuf;

	/* full or low speed config */
	dev->config = (void *) kbuf;
	total = le16_to_cpup (&dev->config->wTotalLength);
	if (!is_valid_config (dev->config) || total >= length)
		goto fail;
	kbuf += total;
	length -= total;

	/* optional high speed config */
	if (kbuf [1] == USB_DT_CONFIG) {
		dev->hs_config = (void *) kbuf;
		total = le16_to_cpup (&dev->hs_config->wTotalLength);
		if (!is_valid_config (dev->hs_config) || total >= length)
			goto fail;
		kbuf += total;
		length -= total;
	}

	/* could support multiple configs, using another encoding! */

	/* device descriptor (tweaked for paranoia) */
	if (length != USB_DT_DEVICE_SIZE)
		goto fail;
	dev->dev = (void *)kbuf;
	if (dev->dev->bLength != USB_DT_DEVICE_SIZE
			|| dev->dev->bDescriptorType != USB_DT_DEVICE
			|| dev->dev->bNumConfigurations != 1)
		goto fail;
	dev->dev->bNumConfigurations = 1;
	dev->dev->bcdUSB = __constant_cpu_to_le16 (0x0200);

	/* triggers gadgetfs_bind(); then we can enumerate. */
	spin_unlock_irq (&dev->lock);
	value = usb_gadget_register_driver (&gadgetfs_driver);
	if (value != 0) {
		kfree (dev->buf);
		dev->buf = 0;
	} else {
		/* at this point "good" hardware has for the first time
		 * let the USB the host see us.  alternatively, if users
		 * unplug/replug that will clear all the error state.
		 *
		 * note:  everything running before here was guaranteed
		 * to choke driver model style diagnostics.  from here
		 * on, they can work ... except in cleanup paths that
		 * kick in after the ep0 descriptor is closed.
		 */
		fd->f_op = &ep0_io_operations;
		value = len;
	}
	return value;

fail:
	spin_unlock_irq (&dev->lock);
	pr_debug ("%s: %s fail %d, %p\n", shortname, __FUNCTION__, value, dev);
	kfree (dev->buf);
	dev->buf = 0;
	return value;
}

static int
dev_open (struct inode *inode, struct file *fd)
{
	struct dev_data		*dev = inode->u.generic_ip;
	int			value = -EBUSY;

	if (dev->state == STATE_DEV_DISABLED) {
		dev->ev_next = 0;
		dev->state = STATE_OPENED;
		fd->private_data = dev;
		get_dev (dev);
		value = 0;
	}
	return value;
}

static struct file_operations dev_init_operations = {
	.owner =	THIS_MODULE,
	.open =		dev_open,
	.write =	dev_config,
	.fasync =	ep0_fasync,
	.ioctl =	dev_ioctl,
	.release =	dev_release,
};

/*----------------------------------------------------------------------*/

/*
 * implementation for 2.4 uses character special files
 *  ep0/device file	MKDEV (c_major, 0)
 *  first data ep	MKDEV (c_major, 1)
 *  second data ep	MKDEV (c_major, 2)
 *  ...
 *
 *  FIXME can do it as a real filesystem on 2.4 too, without libfs
 */
static int c_major = 240;	/* 240 is local/experimental */
MODULE_PARM (c_major, "i");
MODULE_PARM_DESC (c_major, "major number for char special files");

static int gadget_open (struct inode *ino, struct file *fp)
{
	int			num = minor (ino->i_rdev);
	struct dev_data		*dev;
	struct file_operations	*ops;

	/* ep0 file, "/dev/gadget/$CHIP" */
	if (num == 0) {
		int		status;

		if (the_device != 0)
			return -EBUSY;
		the_device = dev_new ();
		if (the_device == 0)
			return -ENOMEM;

		dev = the_device;
		ino->u.generic_ip = dev;
		ops = &dev_init_operations;
		fp->f_op = ops;

		status = ops->open (ino, fp);
		if (status < 0) {
			put_dev (dev);
			the_device = 0;
		}
		return status;

	/* ep files, "/dev/gadget/$ENDPOINT" */
	} else {
		struct list_head	*entry;
		struct ep_data		*data;

		/* unavailable till device is initted */
		dev = the_device;
		if (dev == 0)
			return -ENODEV;

		/* order in controller's name listing matters! */
		list_for_each (entry, &dev->epfiles) {
			if (--num == 0)
				goto found;
		}
		return -ENODEV;
found:
		data = list_entry (entry, struct ep_data, epfiles);
		ino->u.generic_ip = data;
		ops = &ep_config_operations;
		fp->f_op = ops;

		return ops->open (ino, fp);
	}
}

static struct file_operations gadget_fops = {
	.owner =	THIS_MODULE,
	.open =		gadget_open,
};

/*----------------------------------------------------------------------*/

static int __init init (void)
{
	int status;

	status = register_chrdev (c_major, shortname, &gadget_fops);
	if (status < 0) {
		printk (KERN_WARNING "%s: can't get major %d\n",
			shortname, c_major);
		return status;
	}

	/* dynamic assignment */
	if (c_major == 0)
		c_major = status;
	status = 0;

	pr_info ("%s: using char major %d\n", shortname, c_major);

	if (status == 0)
		pr_info ("%s: %s, version " DRIVER_VERSION "\n",
			shortname, driver_desc);
	return status;
}
module_init (init);

static void __exit cleanup (void)
{
	pr_debug ("unregister %s\n", shortname);
	unregister_chrdev (c_major, shortname);
}
module_exit (cleanup);