/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 *
 * Copyright (C) by Linux Kernel Developers
 *
 * Based on code from the Linux Kernel
 * available at http://www.kernel.org
 * Original file: <kernel>/include/linux/usb/ch9.h
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

/*
 * 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 _CH9_H_
#define _CH9_H_

#include "stdint.h"

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

/* CONTROL REQUEST SUPPORT */

/*
 * USB directions
 *
 * This bit flag is used in endpoint descriptors' bEndpointAddress field.
 * It's also one of three fields in control requests bRequestType.
 */
#define USB_DIR_OUT                     0               /* to device */
#define USB_DIR_IN                      0x80            /* to host */

/*
 * USB types, the second of three bRequestType fields
 */
#define USB_TYPE_MASK                   (0x03 << 5)
#define USB_TYPE_STANDARD               (0x00 << 5)
#define USB_TYPE_CLASS                  (0x01 << 5)
#define USB_TYPE_VENDOR                 (0x02 << 5)
#define USB_TYPE_RESERVED               (0x03 << 5)

/*
 * USB recipients, the third of three bRequestType fields
 */
#define USB_RECIP_MASK                  0x1f
#define USB_RECIP_DEVICE                0x00
#define USB_RECIP_INTERFACE             0x01
#define USB_RECIP_ENDPOINT              0x02
#define USB_RECIP_OTHER                 0x03

/*
 * Standard requests, for the bRequest field of a SETUP packet.
 *
 * These are qualified by the bRequestType field, so that for example
 * TYPE_CLASS or TYPE_VENDOR specific feature flags could be retrieved
 * by a GET_STATUS request.
 */
#define USB_REQ_GET_STATUS              0x00
#define USB_REQ_CLEAR_FEATURE           0x01
#define USB_REQ_SET_FEATURE             0x03
#define USB_REQ_SET_ADDRESS             0x05
#define USB_REQ_GET_DESCRIPTOR          0x06
#define USB_REQ_SET_DESCRIPTOR          0x07
#define USB_REQ_GET_CONFIGURATION       0x08
#define USB_REQ_SET_CONFIGURATION       0x09
#define USB_REQ_GET_INTERFACE           0x0A
#define USB_REQ_SET_INTERFACE           0x0B
#define USB_REQ_SYNCH_FRAME             0x0C
/*
 * USB feature flags are written using USB_REQ_{CLEAR,SET}_FEATURE, and
 * are read as a bit array returned by USB_REQ_GET_STATUS.  (So there
 * are at most sixteen features of each type.)  Hubs may also support a
 * new USB_REQ_TEST_AND_SET_FEATURE to put ports into L1 suspend.
 */
#define USB_DEVICE_SELF_POWERED         0   /* (read only) */
#define USB_DEVICE_REMOTE_WAKEUP        1   /* dev may initiate wakeup */
#define USB_DEVICE_TEST_MODE            2   /* (wired high speed only) */
#define USB_DEVICE_BATTERY              2   /* (wireless) */
#define USB_DEVICE_B_HNP_ENABLE         3   /* (otg) dev may initiate HNP */
#define USB_DEVICE_WUSB_DEVICE          3   /* (wireless)*/
#define USB_DEVICE_A_HNP_SUPPORT        4   /* (otg) RH port supports HNP */
#define USB_DEVICE_A_ALT_HNP_SUPPORT    5   /* (otg) other RH port does */
#define USB_DEVICE_DEBUG_MODE           6   /* (special devices only) */

#define USB_ENDPOINT_HALT       0   /* IN/OUT will STALL */


/**
 * struct usb_ctrlrequest - SETUP data for a USB device control request
 * @bRequestType: matches the USB bmRequestType field
 * @bRequest: matches the USB bRequest field
 * @wValue: matches the USB wValue field (le16 byte order)
 * @wIndex: matches the USB wIndex field (le16 byte order)
 * @wLength: matches the USB wLength field (le16 byte order)
 *
 * This structure is used to send control requests to a USB device.  It matches
 * the different fields of the USB 2.0 Spec section 9.3, table 9-2.  See the
 * USB spec for a fuller description of the different fields, and what they are
 * used for.
 *
 * Note that the driver for any interface can issue control requests.
 * For most devices, interfaces don't coordinate with each other, so
 * such requests may be made at any time.
 */
struct usb_ctrlrequest {
        uint8_t bRequestType;
        uint8_t bRequest;
        uint16_t wValue;
        uint16_t wIndex;
        uint16_t wLength;
} __attribute__ ((packed));

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

/*
 * STANDARD DESCRIPTORS ... as returned by GET_DESCRIPTOR, or
 * (rarely) accepted by SET_DESCRIPTOR.
 *
 * Note that all multi-byte values here are encoded in little endian
 * byte order "on the wire".  But when exposed through Linux-USB APIs,
 * they've been converted to cpu byte order.
 */

/*
 * Descriptor types ... USB 2.0 spec table 9.5
 */
#define USB_DT_DEVICE                   0x01
#define USB_DT_CONFIG                   0x02
#define USB_DT_STRING                   0x03
#define USB_DT_INTERFACE                0x04
#define USB_DT_ENDPOINT                 0x05
#define USB_DT_DEVICE_QUALIFIER         0x06
#define USB_DT_OTHER_SPEED_CONFIG       0x07
#define USB_DT_INTERFACE_POWER          0x08
/* these are from a minor usb 2.0 revision (ECN) */
#define USB_DT_OTG                      0x09
#define USB_DT_DEBUG                    0x0a
#define USB_DT_INTERFACE_ASSOCIATION    0x0b
/* these are from the Wireless USB spec */
#define USB_DT_SECURITY                 0x0c
#define USB_DT_KEY                      0x0d
#define USB_DT_ENCRYPTION_TYPE          0x0e
#define USB_DT_BOS                      0x0f
#define USB_DT_DEVICE_CAPABILITY        0x10
#define USB_DT_WIRELESS_ENDPOINT_COMP   0x11
#define USB_DT_WIRE_ADAPTER             0x21
#define USB_DT_RPIPE                    0x22
#define USB_DT_CS_RADIO_CONTROL         0x23

/* Conventional codes for class-specific descriptors.  The convention is
 * defined in the USB "Common Class" Spec (3.11).  Individual class specs
 * are authoritative for their usage, not the "common class" writeup.
 */
#define USB_DT_CS_DEVICE                (USB_TYPE_CLASS | USB_DT_DEVICE)
#define USB_DT_CS_CONFIG                (USB_TYPE_CLASS | USB_DT_CONFIG)
#define USB_DT_CS_STRING                (USB_TYPE_CLASS | USB_DT_STRING)
#define USB_DT_CS_INTERFACE             (USB_TYPE_CLASS | USB_DT_INTERFACE)
#define USB_DT_CS_ENDPOINT              (USB_TYPE_CLASS | USB_DT_ENDPOINT)

/* All standard descriptors have these 2 fields at the beginning */
struct usb_descriptor_header {
        uint8_t  bLength;
        uint8_t  bDescriptorType;
} __attribute__ ((packed));


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

/* USB_DT_DEVICE: Device descriptor */
struct usb_device_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint16_t bcdUSB;
        uint8_t  bDeviceClass;
        uint8_t  bDeviceSubClass;
        uint8_t  bDeviceProtocol;
        uint8_t  bMaxPacketSize0;
        uint16_t idVendor;
        uint16_t idProduct;
        uint16_t bcdDevice;
        uint8_t  iManufacturer;
        uint8_t  iProduct;
        uint8_t  iSerialNumber;
        uint8_t  bNumConfigurations;
} __attribute__ ((packed));

#define USB_DT_DEVICE_SIZE              18


/*
 * Device and/or Interface Class codes
 * as found in bDeviceClass or bInterfaceClass
 * and defined by www.usb.org documents
 */
#define USB_CLASS_PER_INTERFACE         0       /* for DeviceClass */
#define USB_CLASS_AUDIO                 1
#define USB_CLASS_COMM                  2
#define USB_CLASS_HID                   3
#define USB_CLASS_PHYSICAL              5
#define USB_CLASS_STILL_IMAGE           6
#define USB_CLASS_PRINTER               7
#define USB_CLASS_MASS_STORAGE          8
#define USB_CLASS_HUB                   9
#define USB_CLASS_CDC_DATA              0x0a
#define USB_CLASS_CSCID                 0x0b    /* chip+ smart card */
#define USB_CLASS_CONTENT_SEC           0x0d    /* content security */
#define USB_CLASS_VIDEO                 0x0e
#define USB_CLASS_WIRELESS_CONTROLLER   0xe0
#define USB_CLASS_MISC                  0xef
#define USB_CLASS_APP_SPEC              0xfe
#define USB_CLASS_VENDOR_SPEC           0xff

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

/* USB_DT_CONFIG: Configuration descriptor information.
 *
 * USB_DT_OTHER_SPEED_CONFIG is the same descriptor, except that the
 * descriptor type is different.  Highspeed-capable devices can look
 * different depending on what speed they're currently running.  Only
 * devices with a USB_DT_DEVICE_QUALIFIER have any OTHER_SPEED_CONFIG
 * descriptors.
 */
struct usb_config_descriptor {
       uint8_t  bLength;
       uint8_t  bDescriptorType;

       uint16_t wTotalLength;
       uint8_t  bNumInterfaces;
       uint8_t  bConfigurationValue;
       uint8_t  iConfiguration;
       uint8_t  bmAttributes;
       uint8_t  bMaxPower;
} __attribute__ ((packed));

#define USB_DT_CONFIG_SIZE              9

/* from config descriptor bmAttributes */
#define USB_CONFIG_ATT_ONE              (1 << 7)        /* must be set */
#define USB_CONFIG_ATT_SELFPOWER        (1 << 6)        /* self powered */
#define USB_CONFIG_ATT_WAKEUP           (1 << 5)        /* can wakeup */
#define USB_CONFIG_ATT_BATTERY          (1 << 4)        /* battery powered */

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

/* USB_DT_STRING: String descriptor */
struct usb_string_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint16_t wString[];             /* UTF-16LE encoded */
} __attribute__ ((packed));

/* note that "string" zero is special, it holds language codes that
 * the device supports, not Unicode characters.
 */

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

/* USB_DT_INTERFACE: Interface descriptor */
struct usb_interface_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint8_t  bInterfaceNumber;
        uint8_t  bAlternateSetting;
        uint8_t  bNumEndpoints;
        uint8_t  bInterfaceClass;
        uint8_t  bInterfaceSubClass;
        uint8_t  bInterfaceProtocol;
        uint8_t  iInterface;
} __attribute__ ((packed));

#define USB_DT_INTERFACE_SIZE           9

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

/* USB_DT_ENDPOINT: Endpoint descriptor */
struct usb_endpoint_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint8_t  bEndpointAddress;
        uint8_t  bmAttributes;
        uint16_t wMaxPacketSize;
        uint8_t  bInterval;
} __attribute__ ((packed));

#define USB_DT_ENDPOINT_SIZE            7
#define USB_DT_ENDPOINT_AUDIO_SIZE      9       /* Audio extension */


/*
 * Endpoints
 */
#define USB_ENDPOINT_NUMBER_MASK        0x0f    /* in bEndpointAddress */
#define USB_ENDPOINT_DIR_MASK           0x80

#define USB_ENDPOINT_XFERTYPE_MASK      0x03    /* in bmAttributes */
#define USB_ENDPOINT_XFER_CONTROL       0
#define USB_ENDPOINT_XFER_ISOC          1
#define USB_ENDPOINT_XFER_BULK          2
#define USB_ENDPOINT_XFER_INT           3
#define USB_ENDPOINT_MAX_ADJUSTABLE     0x80


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

/* USB_DT_DEVICE_QUALIFIER: Device Qualifier descriptor */
struct usb_qualifier_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint16_t bcdUSB;
        uint8_t  bDeviceClass;
        uint8_t  bDeviceSubClass;
        uint8_t  bDeviceProtocol;
        uint8_t  bMaxPacketSize0;
        uint8_t  bNumConfigurations;
        uint8_t  bRESERVED;
} __attribute__ ((packed));


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

/* USB_DT_OTG (from OTG 1.0a supplement) */
struct usb_otg_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        uint8_t  bmAttributes;  /* support for HNP, SRP, etc */
} __attribute__ ((packed));

/* from usb_otg_descriptor.bmAttributes */
#define USB_OTG_SRP             (1 << 0)
#define USB_OTG_HNP             (1 << 1)        /* swap host/device roles */

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

/* USB_DT_DEBUG:  for special highspeed devices, replacing serial console */
struct usb_debug_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;

        /* bulk endpoints with 8 byte maxpacket */
        uint8_t  bDebugInEndpoint;
        uint8_t  bDebugOutEndpoint;
} __attribute__((packed));

/*-------------------------------------------------------------------------*/
/* USB 2.0 defines three speeds, here's how Linux identifies them */

enum usb_device_speed {
        USB_SPEED_UNKNOWN = 0,                  /* enumerating */
        USB_SPEED_LOW, USB_SPEED_FULL,          /* usb 1.1 */
        USB_SPEED_HIGH,                         /* usb 2.0 */
        USB_SPEED_VARIABLE,                     /* wireless (usb 2.5) */
};

enum usb_device_state {
        /* NOTATTACHED isn't in the USB spec, and this state acts
         * the same as ATTACHED ... but it's clearer this way.
         */
        USB_STATE_NOTATTACHED = 0,

        /* chapter 9 and authentication (wireless) device states */
        USB_STATE_ATTACHED,
        USB_STATE_POWERED,                      /* wired */
        USB_STATE_UNAUTHENTICATED,              /* auth */
        USB_STATE_RECONNECTING,                 /* auth */
        USB_STATE_DEFAULT,                      /* limited function */
        USB_STATE_ADDRESS,
        USB_STATE_CONFIGURED,                   /* most functions */

        USB_STATE_SUSPENDED

        /* NOTE:  there are actually four different SUSPENDED
         * states, returning to POWERED, DEFAULT, ADDRESS, or
         * CONFIGURED respectively when SOF tokens flow again.
         * At this level there's no difference between L1 and L2
         * suspend states.  (L2 being original USB 1.1 suspend.)
         */
};

/**
 * struct usb_string - wraps a C string and its USB id
 * @id:the (nonzero) ID for this string
 * @s:the string, in UTF-8 encoding
 *
 * If you're using usb_gadget_get_string(), use this to wrap a string
 * together with its ID.
 */
struct usb_string {
        uint8_t id;
        const char* s;
};

/**
 * struct usb_gadget_strings - a set of USB strings in a given language
 * @language:identifies the strings' language (0x0409 for en-us)
 * @strings:array of strings with their ids
 *
 * If you're using usb_gadget_get_string(), use this to wrap all the
 * strings for a given language.
 */
struct usb_gadget_strings {
        uint16_t language;                      /* 0x0409 for en-us */
        struct usb_string* strings;
};

#endif /*_CH9_H_*/
