Merge branch 'for-linus' of master.kernel.org:/pub/scm/linux/kernel/git/dtor/input

[linux-2.6-omap-h63xx.git] / include / linux / usb / ch9.h

diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index ae7833749fa2c3b0f6e0cbc69744efe6734dcdff..1122a6c2c1a3dc3759c1dee7ef6988f24240dee3 100644 (file)
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -1,8 +1,9 @@
 /*
- * This file holds USB constants and structures that are needed for USB
- * device APIs.  These are used by the USB device model, which is defined
- * in chapter 9 of the USB 2.0 specification.  Linux has several APIs in C
- * that need these:
+ * This file holds USB constants and structures that are needed for
+ * USB device APIs.  These are used by the USB device model, which is
+ * defined in chapter 9 of the USB 2.0 specification and in the
+ * Wireless USB 1.0 (spread around).  Linux has several APIs in C that
+ * need these:
  *
  * - the master/host side Linux-USB kernel driver API;
  * - the "usbfs" user space API; and
@@ -14,6 +15,19 @@
  *
  * There's also "Wireless USB", using low power short range radios for
  * peripheral interconnection but otherwise building on the USB framework.
+ *
+ * Note all descriptors are declared '__attribute__((packed))' so that:
+ *
+ * [a] they never get padded, either internally (USB spec writers
+ *     probably handled that) or externally;
+ *
+ * [b] so that accessing bigger-than-a-bytes fields will never
+ *     generate bus errors on any platform, even when the location of
+ *     its descriptor inside a bundle isn't "naturally aligned", and
+ *
+ * [c] for consistency, removing all doubt even when it appears to
+ *     someone that the two other points are non-issues for that
+ *     particular descriptor type.
  */
 
 #ifndef __LINUX_USB_CH9_H
@@ -367,7 +381,7 @@ struct usb_debug_descriptor {
        /* bulk endpoints with 8 byte maxpacket */
        __u8  bDebugInEndpoint;
        __u8  bDebugOutEndpoint;
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -396,7 +410,7 @@ struct usb_security_descriptor {
 
        __le16 wTotalLength;
        __u8  bNumEncryptionTypes;
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -410,7 +424,7 @@ struct usb_key_descriptor {
        __u8  tTKID[3];
        __u8  bReserved;
        __u8  bKeyData[0];
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -426,7 +440,7 @@ struct usb_encryption_descriptor {
 #define        USB_ENC_TYPE_RSA_1              3       /* rsa3072/sha1 auth */
        __u8  bEncryptionValue;         /* use in SET_ENCRYPTION */
        __u8  bAuthKeyIndex;
-};
+} __attribute__((packed));
 
 
 /*-------------------------------------------------------------------------*/
@@ -438,7 +452,7 @@ struct usb_bos_descriptor {
 
        __le16 wTotalLength;
        __u8  bNumDeviceCaps;
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -447,7 +461,7 @@ struct usb_dev_cap_header {
        __u8  bLength;
        __u8  bDescriptorType;
        __u8  bDevCapabilityType;
-};
+} __attribute__((packed));
 
 #define        USB_CAP_TYPE_WIRELESS_USB       1
 
@@ -475,7 +489,7 @@ struct usb_wireless_cap_descriptor {        /* Ultra Wide Band */
        __u8  bmFFITXPowerInfo; /* FFI power levels */
        __le16 bmBandGroup;
        __u8  bReserved;
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -496,7 +510,7 @@ struct usb_wireless_ep_comp_descriptor {
 #define USB_ENDPOINT_SWITCH_NO         0
 #define USB_ENDPOINT_SWITCH_SWITCH     1
 #define USB_ENDPOINT_SWITCH_SCALE      2
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -512,7 +526,7 @@ struct usb_handshake {
        __u8 CDID[16];
        __u8 nonce[16];
        __u8 MIC[8];
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/
 
@@ -524,7 +538,7 @@ struct usb_connection_context {
        __u8 CHID[16];          /* persistent host id */
        __u8 CDID[16];          /* device id (unique w/in host context) */
        __u8 CK[16];            /* connection key */
-};
+} __attribute__((packed));
 
 /*-------------------------------------------------------------------------*/