1 files changed, 55 insertions, 0 deletions
diff --git a/kernel/include/linux/usb/ch9.h b/kernel/include/linux/usb/ch9.h
new file mode 100644
index 000000000..27603bcbb
--- /dev/null
+++ b/kernel/include/linux/usb/ch9.h
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+/*
+ * 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
+ * - the Linux "gadget" slave/device/peripheral side driver API.
+ *
+ * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
+ * act either as a USB master/host or as a USB slave/device.  That means
+ * the master and slave side APIs benefit from working well together.
+ *
+ * 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
+#define __LINUX_USB_CH9_H
+
+#include <uapi/linux/usb/ch9.h>
+
+
+/**
+ * usb_speed_string() - Returns human readable-name of the speed.
+ * @speed: The speed to return human-readable name for.  If it's not
+ *   any of the speeds defined in usb_device_speed enum, string for
+ *   USB_SPEED_UNKNOWN will be returned.
+ */
+extern const char *usb_speed_string(enum usb_device_speed speed);
+
+
+/**
+ * usb_state_string - Returns human readable name for the state.
+ * @state: The state to return a human-readable name for. If it's not
+ *	any of the states devices in usb_device_state_string enum,
+ *	the string UNKNOWN will be returned.
+ */
+extern const char *usb_state_string(enum usb_device_state state);
+
+#endif /* __LINUX_USB_CH9_H */