inode.c

ARM S3C2410 USB SLAVE LINUX驱动

	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;

		data->inode = gadgetfs_create_file (dev->sb, data->name,
				data, &ep_config_operations,
				&data->dentry);
		if (!data->inode) {
			kfree (data);
			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 = NULL;
	set_gadget_data (gadget, NULL);

	/* 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 %s controller not %s\n",
			shortname, CHIP, 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 = NULL;
	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 = ...
	},
};

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

static void gadgetfs_nop(struct usb_gadget *arg) { }

static int gadgetfs_probe (struct usb_gadget *gadget)
{
	CHIP = gadget->name;
	return -EISNAM;
}

static struct usb_gadget_driver probe_driver = {
	.speed		= USB_SPEED_HIGH,
	.bind		= gadgetfs_probe,
	.unbind		= gadgetfs_nop,
	.setup		= (void *)gadgetfs_nop,
	.disconnect	= gadgetfs_nop,
	.driver 	= {
		.name		= "nop",
	},
};


/* 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 if gadget->is_otg, _must_ include an otg descriptor */
	/* FIXME check lengths: walk to end */
}

static ssize_t
dev_config (struct file *fd, const char __user *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 = NULL;
	} 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 %Zd, %p\n", shortname, __FUNCTION__, value, dev);
	kfree (dev->buf);
	dev->buf = NULL;
	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,
	.llseek =	no_llseek,

	.open =		dev_open,
	.write =	dev_config,
	.fasync =	ep0_fasync,
	.ioctl =	dev_ioctl,
	.release =	dev_release,
};

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

/* FILESYSTEM AND SUPERBLOCK OPERATIONS
 *
 * Mounting the filesystem creates a controller file, used first for
 * device configuration then later for event monitoring.
 */


/* FIXME PAM etc could set this security policy without mount options
 * if epfiles inherited ownership and permissons from ep0 ...
 */

static unsigned default_uid;
static unsigned default_gid;
static unsigned default_perm = S_IRUSR | S_IWUSR;

module_param (default_uid, uint, 0644);
module_param (default_gid, uint, 0644);
module_param (default_perm, uint, 0644);


static struct inode *
gadgetfs_make_inode (struct super_block *sb,
		void *data, struct file_operations *fops,
		int mode)
{
	struct inode *inode = new_inode (sb);

	if (inode) {
		inode->i_mode = mode;
		inode->i_uid = default_uid;
		inode->i_gid = default_gid;
		inode->i_blksize = PAGE_CACHE_SIZE;
		inode->i_blocks = 0;
		inode->i_atime = inode->i_mtime = inode->i_ctime
				= CURRENT_TIME;
		inode->u.generic_ip = data;
		inode->i_fop = fops;
	}
	return inode;
}

/* creates in fs root directory, so non-renamable and non-linkable.
 * so inode and dentry are paired, until device reconfig.
 */
static struct inode *
gadgetfs_create_file (struct super_block *sb, char const *name,
		void *data, struct file_operations *fops,
		struct dentry **dentry_p)
{
	struct dentry	*dentry;
	struct inode	*inode;

	dentry = d_alloc_name(sb->s_root, name);
	if (!dentry)
		return NULL;

	inode = gadgetfs_make_inode (sb, data, fops,
			S_IFREG | (default_perm & S_IRWXUGO));
	if (!inode) {
		dput(dentry);
		return NULL;
	}
	d_add (dentry, inode);
	*dentry_p = dentry;
	return inode;
}

static struct super_operations gadget_fs_operations = {
	.statfs =	simple_statfs,
	.drop_inode =	generic_delete_inode,
};

static int
gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
{
	struct inode	*inode;
	struct dentry	*d;
	struct dev_data	*dev;

	if (the_device)
		return -ESRCH;

	/* fake probe to determine $CHIP */
	(void) usb_gadget_register_driver (&probe_driver);
	if (!CHIP)
		return -ENODEV;

	/* superblock */
	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = GADGETFS_MAGIC;
	sb->s_op = &gadget_fs_operations;
	sb->s_time_gran = 1;

	/* root inode */
	inode = gadgetfs_make_inode (sb,
			NULL, &simple_dir_operations,
			S_IFDIR | S_IRUGO | S_IXUGO);
	if (!inode)
		return -ENOMEM;
	inode->i_op = &simple_dir_inode_operations;
	if (!(d = d_alloc_root (inode))) {
		iput (inode);
		return -ENOMEM;
	}
	sb->s_root = d;

	/* the ep0 file is named after the controller we expect;
	 * user mode code can use it for sanity checks, like we do.
	 */
	dev = dev_new ();
	if (!dev)
		return -ENOMEM;

	dev->sb = sb;
	if (!(inode = gadgetfs_create_file (sb, CHIP,
				dev, &dev_init_operations,
				&dev->dentry))) {
		put_dev(dev);
		return -ENOMEM;
	}

	/* other endpoint files are available after hardware setup,
	 * from binding to a controller.
	 */
	the_device = dev;
	return 0;
}

/* "mount -t gadgetfs path /dev/gadget" ends up here */
static struct super_block *
gadgetfs_get_sb (struct file_system_type *t, int flags,
		const char *path, void *opts)
{
	return get_sb_single (t, flags, opts, gadgetfs_fill_super);
}

static void
gadgetfs_kill_sb (struct super_block *sb)
{
	kill_litter_super (sb);
	if (the_device) {
		put_dev (the_device);
		the_device = NULL;
	}
}

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

static struct file_system_type gadgetfs_type = {
	.owner		= THIS_MODULE,
	.name		= shortname,
	.get_sb		= gadgetfs_get_sb,
	.kill_sb	= gadgetfs_kill_sb,
};

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

static int __init init (void)
{
	int status;

	status = register_filesystem (&gadgetfs_type);
	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_filesystem (&gadgetfs_type);
}
module_exit (cleanup);