path: root/include/linux/usb_ch9.h

/*
 * 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:
 *
 * - the master/host side Linux-USB kernel driver API;
 * - the "usbfs" user space API; and
 * - (eventually) a Linux "gadget" slave/device 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 will benefit from working well together.
 */

#ifndef __LINUX_USB_CH9_H
#define __LINUX_USB_CH9_H

#include <asm/types.h>		/* __u8 etc */

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

/* 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.)
 */
#define USB_DEVICE_SELF_POWERED		0	/* (read only) */
#define USB_DEVICE_REMOTE_WAKEUP	1	/* dev may initiate wakeup */
#define USB_DEVICE_TEST_MODE		2	/* (high speed only) */
#define USB_DEVICE_B_HNP_ENABLE		3	/* dev may initiate HNP */
#define USB_DEVICE_A_HNP_SUPPORT	4	/* RH port supports HNP */
#define USB_DEVICE_A_ALT_HNP_SUPPORT	5	/* 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 {
	__u8 bRequestType;
	__u8 bRequest;
	__le16 wValue;
	__le16 wIndex;
	__le16 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

/* conventional codes for class-specific descriptors */
#define USB_DT_CS_DEVICE		0x21
#define USB_DT_CS_CONFIG		0x22
#define USB_DT_CS_STRING		0x23
#define USB_DT_CS_INTERFACE		0x24
#define USB_DT_CS_ENDPOINT		0x25

/* All standard descriptors have these 2 fields at the beginning */
struct usb_descriptor_header {
	__u8  bLength;
	__u8  bDescriptorType;
} __attribute__ ((packed));


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

/* USB_DT_DEVICE: Device descriptor */
struct usb_device_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__le16 bcdUSB;
	__u8  bDeviceClass;
	__u8  bDeviceSubClass;
	__u8  bDeviceProtocol;
	__u8  bMaxPacketSize0;
	__le16 idVendor;
	__le16 idProduct;
	__le16 bcdDevice;
	__u8  iManufacturer;
	__u8  iProduct;
	__u8  iSerialNumber;
	__u8  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_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 {
	__u8  bLength;
	__u8  bDescriptorType;

	__le16 wTotalLength;
	__u8  bNumInterfaces;
	__u8  bConfigurationValue;
	__u8  iConfiguration;
	__u8  bmAttributes;
	__u8  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 */

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

/* USB_DT_STRING: String descriptor */
struct usb_string_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__le16 wData[1];		/* 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 {
	__u8  bLength;
	__u8  bDescriptorType;

	__u8  bInterfaceNumber;
	__u8  bAlternateSetting;
	__u8  bNumEndpoints;
	__u8  bInterfaceClass;
	__u8  bInterfaceSubClass;
	__u8  bInterfaceProtocol;
	__u8  iInterface;
} __attribute__ ((packed));

#define USB_DT_INTERFACE_SIZE		9

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

/* USB_DT_ENDPOINT: Endpoint descriptor */
struct usb_endpoint_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__u8  bEndpointAddress;
	__u8  bmAttributes;
	__le16 wMaxPacketSize;
	__u8  bInterval;

	// NOTE:  these two are _only_ in audio endpoints.
	// use USB_DT_ENDPOINT*_SIZE in bLength, not sizeof.
	__u8  bRefresh;
	__u8  bSynchAddress;
} __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


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

/* USB_DT_DEVICE_QUALIFIER: Device Qualifier descriptor */
struct usb_qualifier_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__le16 bcdUSB;
	__u8  bDeviceClass;
	__u8  bDeviceSubClass;
	__u8  bDeviceProtocol;
	__u8  bMaxPacketSize0;
	__u8  bNumConfigurations;
	__u8  bRESERVED;
} __attribute__ ((packed));


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

/* USB_DT_OTG (from OTG 1.0a supplement) */
struct usb_otg_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__u8  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 {
	__u8  bLength;
	__u8  bDescriptorType;

	/* bulk endpoints with 8 byte maxpacket */
	__u8  bDebugInEndpoint;
	__u8  bDebugOutEndpoint;
};

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

/* USB_DT_INTERFACE_ASSOCIATION: groups interfaces */
struct usb_interface_assoc_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;

	__u8  bFirstInterface;
	__u8  bInterfaceCount;
	__u8  bFunctionClass;
	__u8  bFunctionSubClass;
	__u8  bFunctionProtocol;
	__u8  iFunction;
} __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 */
};

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,

	/* the chapter 9 device states */
	USB_STATE_ATTACHED,
	USB_STATE_POWERED,
	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.
	 */
};

#endif	/* __LINUX_USB_CH9_H */