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>

5 files changed, 116 insertions, 0 deletions

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 5e113db41b59..cb69aa1e02e8 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -295,6 +295,7 @@ static int usb_parse_configuration(struct device *ddev, int cfgidx,
         struct usb_descriptor_header *header;
         int len, retval;
         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
+        unsigned iad_num = 0;
 
         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
@@ -372,6 +373,20 @@ static int usb_parse_configuration(struct device *ddev, int cfgidx,
                                 ++n;
                         }
 
+                } else if (header->bDescriptorType ==
+                                USB_DT_INTERFACE_ASSOCIATION) {
+                        if (iad_num == USB_MAXIADS) {
+                                dev_warn(ddev, "found more Interface "
+                                               "Association Descriptors "
+                                               "than allocated for in "
+                                               "configuration %d\n", cfgno);
+                        } else {
+                                config->intf_assoc[iad_num] =
+                                        (struct usb_interface_assoc_descriptor
+                                        *)header;
+                                iad_num++;
+                        }
+
                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
                             header->bDescriptorType == USB_DT_CONFIG)
                         dev_warn(ddev, "config %d contains an unexpected "
diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index 6753ca059ee4..87c794d60aa0 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -102,6 +102,10 @@ static const char *format_config =
 /* C:  #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA */
   "C:%c #Ifs=%2d Cfg#=%2d Atr=%02x MxPwr=%3dmA\n";
   
+static const char *format_iad =
+/* A:  FirstIf#=dd IfCount=dd Cls=xx(sssss) Sub=xx Prot=xx */
+  "A:  FirstIf#=%2d IfCount=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x\n";
+
 static const char *format_iface =
 /* I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=xxxx*/
   "I:%c If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";
@@ -146,6 +150,7 @@ static const struct class_info clas_info[] =
         {USB_CLASS_STILL_IMAGE,         "still"},
         {USB_CLASS_CSCID,               "scard"},
         {USB_CLASS_CONTENT_SEC,         "c-sec"},
+        {USB_CLASS_VIDEO,               "video"},
         {-1,                            "unk."}         /* leave as last */
 };
 
@@ -286,6 +291,21 @@ static char *usb_dump_interface(
         return start;
 }
 
+static char *usb_dump_iad_descriptor(char *start, char *end,
+        const struct usb_interface_assoc_descriptor *iad)
+{
+        if (start > end)
+                return start;
+        start += sprintf(start, format_iad,
+                         iad->bFirstInterface,
+                         iad->bInterfaceCount,
+                         iad->bFunctionClass,
+                         class_decode(iad->bFunctionClass),
+                         iad->bFunctionSubClass,
+                         iad->bFunctionProtocol);
+        return start;
+}
+
 /* TBD:
  * 0. TBDs
  * 1. marking active interface altsettings (code lists all, but should mark
@@ -322,6 +342,12 @@ static char *usb_dump_config (
         if (!config)            /* getting these some in 2.3.7; none in 2.3.6 */
                 return start + sprintf(start, "(null Cfg. desc.)\n");
         start = usb_dump_config_descriptor(start, end, &config->desc, active);
+        for (i = 0; i < USB_MAXIADS; i++) {
+                if (config->intf_assoc[i] == NULL)
+                        break;
+                start = usb_dump_iad_descriptor(start, end,
+                                        config->intf_assoc[i]);
+        }
         for (i = 0; i < config->desc.bNumInterfaces; i++) {
                 intfc = config->intf_cache[i];
                 interface = config->interface[i];
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);
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 5dfe31bc32ba..d47ae89154a7 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -495,6 +495,25 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev)
         sysfs_remove_group(&dev->kobj, &dev_attr_grp);
 }
 
+/* Interface Accociation Descriptor fields */
+#define usb_intf_assoc_attr(field, format_string)                       \
+static ssize_t                                                          \
+show_iad_##field (struct device *dev, struct device_attribute *attr,    \
+                char *buf)                                              \
+{                                                                       \
+        struct usb_interface *intf = to_usb_interface (dev);            \
+                                                                        \
+        return sprintf (buf, format_string,                             \
+                        intf->intf_assoc->field);               \
+}                                                                       \
+static DEVICE_ATTR(iad_##field, S_IRUGO, show_iad_##field, NULL);
+
+usb_intf_assoc_attr (bFirstInterface, "%02x\n")
+usb_intf_assoc_attr (bInterfaceCount, "%02d\n")
+usb_intf_assoc_attr (bFunctionClass, "%02x\n")
+usb_intf_assoc_attr (bFunctionSubClass, "%02x\n")
+usb_intf_assoc_attr (bFunctionProtocol, "%02x\n")
+
 /* Interface fields */
 #define usb_intf_attr(field, format_string)                             \
 static ssize_t                                                          \
@@ -558,6 +577,18 @@ static ssize_t show_modalias(struct device *dev,
 }
 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 
+static struct attribute *intf_assoc_attrs[] = {
+        &dev_attr_iad_bFirstInterface.attr,
+        &dev_attr_iad_bInterfaceCount.attr,
+        &dev_attr_iad_bFunctionClass.attr,
+        &dev_attr_iad_bFunctionSubClass.attr,
+        &dev_attr_iad_bFunctionProtocol.attr,
+        NULL,
+};
+static struct attribute_group intf_assoc_attr_grp = {
+        .attrs = intf_assoc_attrs,
+};
+
 static struct attribute *intf_attrs[] = {
         &dev_attr_bInterfaceNumber.attr,
         &dev_attr_bAlternateSetting.attr,
@@ -609,6 +640,8 @@ int usb_create_sysfs_intf_files(struct usb_interface *intf)
                 alt->string = usb_cache_string(udev, alt->desc.iInterface);
         if (alt->string)
                 retval = device_create_file(dev, &dev_attr_interface);
+        if (intf->intf_assoc)
+                retval = sysfs_create_group(&dev->kobj, &intf_assoc_attr_grp);
         usb_create_intf_ep_files(intf, udev);
         return 0;
 }
@@ -620,4 +653,5 @@ void usb_remove_sysfs_intf_files(struct usb_interface *intf)
         usb_remove_intf_ep_files(intf);
         device_remove_file(dev, &dev_attr_interface);
         sysfs_remove_group(&dev->kobj, &intf_attr_grp);
+        sysfs_remove_group(&intf->dev.kobj, &intf_assoc_attr_grp);
 }
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 533c32374e01..7a60946df3b6 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -146,6 +146,10 @@ struct usb_interface {
                                          * active alternate setting */
         unsigned num_altsetting;        /* number of alternate settings */
 
+        /* If there is an interface association descriptor then it will list
+         * the associated interfaces */
+        struct usb_interface_assoc_descriptor *intf_assoc;
+
         int minor;                      /* minor number this interface is
                                          * bound to */
         enum usb_interface_condition condition;         /* state of binding */
@@ -175,6 +179,7 @@ void usb_put_intf(struct usb_interface *intf);
 
 /* this maximum is arbitrary */
 #define USB_MAXINTERFACES       32
+#define USB_MAXIADS             USB_MAXINTERFACES/2
 
 /**
  * struct usb_interface_cache - long-term representation of a device interface
@@ -245,6 +250,11 @@ struct usb_host_config {
         struct usb_config_descriptor    desc;
 
         char *string;           /* iConfiguration string, if present */
+
+        /* List of any Interface Association Descriptors in this
+         * configuration. */
+        struct usb_interface_assoc_descriptor *intf_assoc[USB_MAXIADS];
+
         /* the interfaces associated with this configuration,
          * stored in no particular order */
         struct usb_interface *interface[USB_MAXINTERFACES];