USB: add IAD support to usbfs and sysfs

USB_IAD: Adds support for USB Interface Association Descriptors.

This patch adds support to the USB host stack for parsing, storing, and
displaying Interface Association Descriptors. In /proc/bus/usb/devices
lines starting with A: show the fields in an IAD. In sysfs if an
interface on a USB device is referenced by an IAD the following files
will be added to the sysfs directory for that interface:
iad_bFirstInterface, iad_bInterfaceCount, iad_bFunctionClass, and
iad_bFunctionSubClass, iad_bFunctionProtocol

Signed-off-by: Craig W. Nadler <craig@nadler.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 4c1432314711..530e854961ce 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1384,6 +1384,36 @@ struct device_type usb_if_device_type = {
 	.uevent =	usb_if_uevent,
 };
 
+static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
+						       struct usb_host_config *config,
+						       u8 inum)
+{
+	struct usb_interface_assoc_descriptor *retval = NULL;
+	struct usb_interface_assoc_descriptor *intf_assoc;
+	int first_intf;
+	int last_intf;
+	int i;
+
+	for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
+		intf_assoc = config->intf_assoc[i];
+		if (intf_assoc->bInterfaceCount == 0)
+			continue;
+
+		first_intf = intf_assoc->bFirstInterface;
+		last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
+		if (inum >= first_intf && inum <= last_intf) {
+			if (!retval)
+				retval = intf_assoc;
+			else
+				dev_err(&dev->dev, "Interface #%d referenced"
+					" by multiple IADs\n", inum);
+		}
+	}
+
+	return retval;
+}
+
+
 /*
  * usb_set_configuration - Makes a particular device setting be current
  * @dev: the device whose configuration is being updated
@@ -1530,6 +1560,7 @@ free_interfaces:
 		intfc = cp->intf_cache[i];
 		intf->altsetting = intfc->altsetting;
 		intf->num_altsetting = intfc->num_altsetting;
+		intf->intf_assoc = find_iad(dev, cp, i);
 		kref_get(&intfc->ref);
 
 		alt = usb_altnum_to_altsetting(intf, 0);