usb.h

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#ifndef _IPXE_USB_H
#define _IPXE_USB_H

/** @file
 *
 * Universal Serial Bus (USB)
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <byteswap.h>
#include <ipxe/list.h>
#include <ipxe/device.h>
#include <ipxe/process.h>
#include <ipxe/iobuf.h>
#include <ipxe/tables.h>

/** USB protocols */
enum usb_protocol {
        /** USB 2.0 */
        USB_PROTO_2_0 = 0x0200,
        /** USB 3.0 */
        USB_PROTO_3_0 = 0x0300,
        /** USB 3.1 */
        USB_PROTO_3_1 = 0x0301,
};

/** Define a USB speed
 *
 * @v mantissa          Mantissa
 * @v exponent          Exponent (in engineering terms: 1=k, 2=M, 3=G)
 * @ret speed           USB speed
 */
#define USB_SPEED( mantissa, exponent ) ( (exponent << 16) | (mantissa) )

/** Extract USB speed mantissa */
#define USB_SPEED_MANTISSA(speed) ( (speed) & 0xffff )

/** Extract USB speed exponent */
#define USB_SPEED_EXPONENT(speed) ( ( (speed) >> 16 ) & 0x3 )

/** USB device speeds */
enum usb_speed {
        /** Not connected */
        USB_SPEED_NONE = 0,
        /** Low speed (1.5Mbps) */
        USB_SPEED_LOW = USB_SPEED ( 1500, 1 ),
        /** Full speed (12Mbps) */
        USB_SPEED_FULL = USB_SPEED ( 12, 2 ),
        /** High speed (480Mbps) */
        USB_SPEED_HIGH = USB_SPEED ( 480, 2 ),
        /** Super speed (5Gbps) */
        USB_SPEED_SUPER = USB_SPEED ( 5, 3 ),
};

/** Define a USB bus:device address
 *
 * @v bus               Bus address
 * @v dev               Device address
 * @ret busdev          Bus:device address
 */
#define USB_BUSDEV( bus, dev ) ( ( (bus) << 8 ) | (dev) )

/** Extract USB bus address */
#define USB_BUS( busdev ) ( (busdev) >> 8 )

/** Extract USB device address */
#define USB_DEV( busdev ) ( (busdev) & 0xff )

/** USB packet IDs */
enum usb_pid {
        /** IN PID */
        USB_PID_IN = 0x69,
        /** OUT PID */
        USB_PID_OUT = 0xe1,
        /** SETUP PID */
        USB_PID_SETUP = 0x2d,
};

/** A USB setup data packet */
struct usb_setup_packet {
        /** Request */
        uint16_t request;
        /** Value parameter */
        uint16_t value;
        /** Index parameter */
        uint16_t index;
        /** Length of data stage */
        uint16_t len;
} __attribute__ (( packed ));

/** Data transfer is from host to device */
#define USB_DIR_OUT ( 0 << 7 )

/** Data transfer is from device to host */
#define USB_DIR_IN ( 1 << 7 )

/** Standard request type */
#define USB_TYPE_STANDARD ( 0 << 5 )

/** Class-specific request type */
#define USB_TYPE_CLASS ( 1 << 5 )

/** Vendor-specific request type */
#define USB_TYPE_VENDOR ( 2 << 5 )

/** Request recipient mask */
#define USB_RECIP_MASK ( 0x1f << 0 )

/** Request recipient is the device */
#define USB_RECIP_DEVICE ( 0 << 0 )

/** Request recipient is an interface */
#define USB_RECIP_INTERFACE ( 1 << 0 )

/** Request recipient is an endpoint */
#define USB_RECIP_ENDPOINT ( 2 << 0 )

/** Construct USB request type */
#define USB_REQUEST_TYPE(type) ( (type) << 8 )

/** Get status */
#define USB_GET_STATUS ( USB_DIR_IN | USB_REQUEST_TYPE ( 0 ) )

/** Clear feature */
#define USB_CLEAR_FEATURE ( USB_DIR_OUT | USB_REQUEST_TYPE ( 1 ) )

/** Set feature */
#define USB_SET_FEATURE ( USB_DIR_OUT | USB_REQUEST_TYPE ( 3 ) )

/** Set address */
#define USB_SET_ADDRESS ( USB_DIR_OUT | USB_REQUEST_TYPE ( 5 ) )

/** Get descriptor */
#define USB_GET_DESCRIPTOR ( USB_DIR_IN | USB_REQUEST_TYPE ( 6 ) )

/** Set descriptor */
#define USB_SET_DESCRIPTOR ( USB_DIR_OUT | USB_REQUEST_TYPE ( 7 ) )

/** Get configuration */
#define USB_GET_CONFIGURATION ( USB_DIR_IN | USB_REQUEST_TYPE ( 8 ) )

/** Set configuration */
#define USB_SET_CONFIGURATION ( USB_DIR_OUT | USB_REQUEST_TYPE ( 9 ) )

/** Get interface */
#define USB_GET_INTERFACE \
        ( USB_DIR_IN | USB_RECIP_INTERFACE | USB_REQUEST_TYPE ( 10 ) )

/** Set interface */
#define USB_SET_INTERFACE \
        ( USB_DIR_OUT | USB_RECIP_INTERFACE | USB_REQUEST_TYPE ( 11 ) )

/** Endpoint halt feature */
#define USB_ENDPOINT_HALT 0

/** A USB class code tuple */
struct usb_class {
        /** Class code */
        uint8_t class;
        /** Subclass code */
        uint8_t subclass;
        /** Protocol code */
        uint8_t protocol;
} __attribute__ (( packed ));

/** Class code for USB hubs */
#define USB_CLASS_HUB 9

/** A USB descriptor header */
struct usb_descriptor_header {
        /** Length of descriptor */
        uint8_t len;
        /** Descriptor type */
        uint8_t type;
} __attribute__ (( packed ));

/** A USB device descriptor */
struct usb_device_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** USB specification release number in BCD */
        uint16_t protocol;
        /** Device class */
        struct usb_class class;
        /** Maximum packet size for endpoint zero */
        uint8_t mtu;
        /** Vendor ID */
        uint16_t vendor;
        /** Product ID */
        uint16_t product;
        /** Device release number in BCD */
        uint16_t release;
        /** Manufacturer string */
        uint8_t manufacturer;
        /** Product string */
        uint8_t name;
        /** Serial number string */
        uint8_t serial;
        /** Number of possible configurations */
        uint8_t configurations;
} __attribute__ (( packed ));

/** A USB device descriptor */
#define USB_DEVICE_DESCRIPTOR 1

/** A USB configuration descriptor */
struct usb_configuration_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** Total length */
        uint16_t len;
        /** Number of interfaces */
        uint8_t interfaces;
        /** Configuration value */
        uint8_t config;
        /** Configuration string */
        uint8_t name;
        /** Attributes */
        uint8_t attributes;
        /** Maximum power consumption */
        uint8_t power;
} __attribute__ (( packed ));

/** A USB configuration descriptor */
#define USB_CONFIGURATION_DESCRIPTOR 2

/** A USB string descriptor */
struct usb_string_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** String */
        char string[0];
} __attribute__ (( packed ));

/** A USB string descriptor */
#define USB_STRING_DESCRIPTOR 3

/** Language ID for English */
#define USB_LANG_ENGLISH 0x0409

/** A USB interface descriptor */
struct usb_interface_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** Interface number */
        uint8_t interface;
        /** Alternate setting */
        uint8_t alternate;
        /** Number of endpoints */
        uint8_t endpoints;
        /** Interface class */
        struct usb_class class;
        /** Interface name */
        uint8_t name;
} __attribute__ (( packed ));

/** A USB interface descriptor */
#define USB_INTERFACE_DESCRIPTOR 4

/** A USB endpoint descriptor */
struct usb_endpoint_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** Endpoint address */
        uint8_t endpoint;
        /** Attributes */
        uint8_t attributes;
        /** Maximum packet size and burst size */
        uint16_t sizes;
        /** Polling interval */
        uint8_t interval;
} __attribute__ (( packed ));

/** A USB endpoint descriptor */
#define USB_ENDPOINT_DESCRIPTOR 5

/** Endpoint attribute transfer type mask */
#define USB_ENDPOINT_ATTR_TYPE_MASK 0x03

/** Endpoint periodic type */
#define USB_ENDPOINT_ATTR_PERIODIC 0x01

/** Control endpoint transfer type */
#define USB_ENDPOINT_ATTR_CONTROL 0x00

/** Bulk endpoint transfer type */
#define USB_ENDPOINT_ATTR_BULK 0x02

/** Interrupt endpoint transfer type */
#define USB_ENDPOINT_ATTR_INTERRUPT 0x03

/** Bulk OUT endpoint (internal) type */
#define USB_BULK_OUT ( USB_ENDPOINT_ATTR_BULK | USB_DIR_OUT )

/** Bulk IN endpoint (internal) type */
#define USB_BULK_IN ( USB_ENDPOINT_ATTR_BULK | USB_DIR_IN )

/** Interrupt IN endpoint (internal) type */
#define USB_INTERRUPT_IN ( USB_ENDPOINT_ATTR_INTERRUPT | USB_DIR_IN )

/** Interrupt OUT endpoint (internal) type */
#define USB_INTERRUPT_OUT ( USB_ENDPOINT_ATTR_INTERRUPT | USB_DIR_OUT )

/** USB endpoint MTU */
#define USB_ENDPOINT_MTU(sizes) ( ( (sizes) >> 0 ) & 0x07ff )

/** USB endpoint maximum burst size */
#define USB_ENDPOINT_BURST(sizes) ( ( (sizes) >> 11 ) & 0x0003 )

/** A USB endpoint companion descriptor */
struct usb_endpoint_companion_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** Maximum burst size */
        uint8_t burst;
        /** Extended attributes */
        uint8_t extended;
        /** Number of bytes per service interval */
        uint16_t periodic;
} __attribute__ (( packed ));

/** A USB endpoint companion descriptor */
#define USB_ENDPOINT_COMPANION_DESCRIPTOR 48

/** A USB interface association descriptor */
struct usb_interface_association_descriptor {
        /** Descriptor header */
        struct usb_descriptor_header header;
        /** First interface number */
        uint8_t first;
        /** Interface count */
        uint8_t count;
        /** Association class */
        struct usb_class class;
        /** Association name */
        uint8_t name;
} __attribute__ (( packed ));

/** A USB interface association descriptor */
#define USB_INTERFACE_ASSOCIATION_DESCRIPTOR 11

/** A class-specific interface descriptor */
#define USB_CS_INTERFACE_DESCRIPTOR 36

/** A class-specific endpoint descriptor */
#define USB_CS_ENDPOINT_DESCRIPTOR 37

/**
 * Get next USB descriptor
 *
 * @v desc              USB descriptor header
 * @ret next            Next USB descriptor header
 */
static inline __attribute__ (( always_inline )) struct usb_descriptor_header *
usb_next_descriptor ( struct usb_descriptor_header *desc ) {

        return ( ( ( void * ) desc ) + desc->len );
}

/**
 * Check that descriptor lies within a configuration descriptor
 *
 * @v config            Configuration descriptor
 * @v desc              Descriptor header
 * @v is_within         Descriptor is within the configuration descriptor
 */
static inline __attribute__ (( always_inline )) int
usb_is_within_config ( struct usb_configuration_descriptor *config,
                       struct usb_descriptor_header *desc ) {
        struct usb_descriptor_header *end =
                ( ( ( void * ) config ) + le16_to_cpu ( config->len ) );

        /* Check that descriptor starts within the configuration
         * descriptor, and that the length does not exceed the
         * configuration descriptor.  This relies on the fact that
         * usb_next_descriptor() needs to access only the first byte
         * of the descriptor in order to determine the length.
         */
        return ( ( desc < end ) && ( usb_next_descriptor ( desc ) <= end ) );
}

/** Iterate over all configuration descriptors */
#define for_each_config_descriptor( desc, config )                         \
        for ( desc = container_of ( &(config)->header,                     \
                                    typeof ( *desc ), header ) ;           \
              usb_is_within_config ( (config), &desc->header ) ;           \
              desc = container_of ( usb_next_descriptor ( &desc->header ), \
                                    typeof ( *desc ), header ) )

/** Iterate over all configuration descriptors within an interface descriptor */
#define for_each_interface_descriptor( desc, config, interface )           \
        for ( desc = container_of ( usb_next_descriptor ( &(interface)->   \
                                                          header ),        \
                                    typeof ( *desc ), header ) ;           \
              ( usb_is_within_config ( (config), &desc->header ) &&        \
                ( desc->header.type != USB_INTERFACE_DESCRIPTOR ) ) ;      \
              desc = container_of ( usb_next_descriptor ( &desc->header ), \
                                    typeof ( *desc ), header ) )

/** A USB endpoint */
struct usb_endpoint {
        /** USB device */
        struct usb_device *usb;
        /** Endpoint address */
        unsigned int address;
        /** Attributes */
        unsigned int attributes;
        /** Maximum transfer size */
        size_t mtu;
        /** Maximum burst size */
        unsigned int burst;
        /** Interval (in microframes) */
        unsigned int interval;

        /** Endpoint is open */
        int open;
        /** Buffer fill level */
        unsigned int fill;

        /** List of halted endpoints */
        struct list_head halted;

        /** Host controller operations */
        struct usb_endpoint_host_operations *host;
        /** Host controller private data */
        void *priv;
        /** Driver operations */
        struct usb_endpoint_driver_operations *driver;

        /** Recycled I/O buffer list */
        struct list_head recycled;
        /** Refill buffer reserved header length */
        size_t reserve;
        /** Refill buffer payload length */
        size_t len;
        /** Maximum fill level */
        unsigned int max;
};

/** USB endpoint host controller operations */
struct usb_endpoint_host_operations {
        /** Open endpoint
         *
         * @v ep                USB endpoint
         * @ret rc              Return status code
         */
        int ( * open ) ( struct usb_endpoint *ep );
        /** Close endpoint
         *
         * @v ep                USB endpoint
         */
        void ( * close ) ( struct usb_endpoint *ep );
        /**
         * Reset endpoint
         *
         * @v ep                USB endpoint
         * @ret rc              Return status code
         */
        int ( * reset ) ( struct usb_endpoint *ep );
        /** Update MTU
         *
         * @v ep                USB endpoint
         * @ret rc              Return status code
         */
        int ( * mtu ) ( struct usb_endpoint *ep );
        /** Enqueue message transfer
         *
         * @v ep                USB endpoint
         * @v iobuf             I/O buffer
         * @ret rc              Return status code
         */
        int ( * message ) ( struct usb_endpoint *ep,
                            struct io_buffer *iobuf );
        /** Enqueue stream transfer
         *
         * @v ep                USB endpoint
         * @v iobuf             I/O buffer
         * @v zlp               Append a zero-length packet
         * @ret rc              Return status code
         */
        int ( * stream ) ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                           int zlp );
};

/** USB endpoint driver operations */
struct usb_endpoint_driver_operations {
        /** Complete transfer
         *
         * @v ep                USB endpoint
         * @v iobuf             I/O buffer
         * @v rc                Completion status code
         */
        void ( * complete ) ( struct usb_endpoint *ep,
                              struct io_buffer *iobuf, int rc );
};

/** Control endpoint address */
#define USB_EP0_ADDRESS 0x00

/** Control endpoint attributes */
#define USB_EP0_ATTRIBUTES 0x00

/** Calculate default MTU based on device speed
 *
 * @v speed             Device speed
 * @ret mtu             Default MTU
 */
#define USB_EP0_DEFAULT_MTU(speed)                      \
        ( ( (speed) >= USB_SPEED_SUPER ) ? 512 :        \
          ( ( (speed) >= USB_SPEED_FULL ) ? 64 : 8 ) )

/** Control endpoint maximum burst size */
#define USB_EP0_BURST 0

/** Control endpoint interval */
#define USB_EP0_INTERVAL 0

/** Maximum endpoint number */
#define USB_ENDPOINT_MAX 0x0f

/** Endpoint direction is in */
#define USB_ENDPOINT_IN 0x80

/** Construct endpoint index from endpoint address */
#define USB_ENDPOINT_IDX(address)                                       \
        ( ( (address) & USB_ENDPOINT_MAX ) |                            \
          ( ( (address) & USB_ENDPOINT_IN ) >> 3 ) )

/**
 * Initialise USB endpoint
 *
 * @v ep                USB endpoint
 * @v usb               USB device
 * @v driver            Driver operations
 */
static inline __attribute__ (( always_inline )) void
usb_endpoint_init ( struct usb_endpoint *ep, struct usb_device *usb,
                    struct usb_endpoint_driver_operations *driver ) {

        ep->usb = usb;
        ep->driver = driver;
}

/**
 * Describe USB endpoint
 *
 * @v ep                USB endpoint
 * @v address           Endpoint address
 * @v attributes        Attributes
 * @v mtu               Maximum packet size
 * @v burst             Maximum burst size
 * @v interval          Interval (in microframes)
 */
static inline __attribute__ (( always_inline )) void
usb_endpoint_describe ( struct usb_endpoint *ep, unsigned int address,
                        unsigned int attributes, size_t mtu,
                        unsigned int burst, unsigned int interval ) {

        ep->address = address;
        ep->attributes = attributes;
        ep->mtu = mtu;
        ep->burst = burst;
        ep->interval = interval;
}

/**
 * Set USB endpoint host controller private data
 *
 * @v ep                USB endpoint
 * @v priv              Host controller private data
 */
static inline __attribute__ (( always_inline )) void
usb_endpoint_set_hostdata ( struct usb_endpoint *ep, void *priv ) {
        ep->priv = priv;
}

/**
 * Get USB endpoint host controller private data
 *
 * @v ep                USB endpoint
 * @ret priv            Host controller private data
 */
static inline __attribute__ (( always_inline )) void *
usb_endpoint_get_hostdata ( struct usb_endpoint *ep ) {
        return ep->priv;
}

extern const char * usb_endpoint_name ( struct usb_endpoint *ep );
extern int
usb_endpoint_described ( struct usb_endpoint *ep,
                         struct usb_configuration_descriptor *config,
                         struct usb_interface_descriptor *interface,
                         unsigned int type, unsigned int index );
extern int usb_endpoint_open ( struct usb_endpoint *ep );
extern int usb_endpoint_clear_halt ( struct usb_endpoint *ep );
extern void usb_endpoint_close ( struct usb_endpoint *ep );
extern int usb_message ( struct usb_endpoint *ep, unsigned int request,
                         unsigned int value, unsigned int index,
                         struct io_buffer *iobuf );
extern int usb_stream ( struct usb_endpoint *ep, struct io_buffer *iobuf,
                        int terminate );
extern void usb_complete_err ( struct usb_endpoint *ep,
                               struct io_buffer *iobuf, int rc );

/**
 * Initialise USB endpoint refill
 *
 * @v ep                USB endpoint
 * @v reserve           Refill buffer reserved header length
 * @v len               Refill buffer payload length (zero for endpoint's MTU)
 * @v max               Maximum fill level
 */
static inline __attribute__ (( always_inline )) void
usb_refill_init ( struct usb_endpoint *ep, size_t reserve, size_t len,
                  unsigned int max ) {

        INIT_LIST_HEAD ( &ep->recycled );
        ep->reserve = reserve;
        ep->len = len;
        ep->max = max;
}

/**
 * Recycle I/O buffer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 */
static inline __attribute__ (( always_inline )) void
usb_recycle ( struct usb_endpoint *ep, struct io_buffer *iobuf ) {

        list_add_tail ( &iobuf->list, &ep->recycled );
}

extern int usb_prefill ( struct usb_endpoint *ep );
extern int usb_refill_limit ( struct usb_endpoint *ep, unsigned int max );
extern int usb_refill ( struct usb_endpoint *ep );
extern void usb_flush ( struct usb_endpoint *ep );

/** A USB class descriptor */
union usb_class_descriptor {
        /** Class */
        struct usb_class class;
        /** Scalar value */
        uint32_t scalar;
};

/**
 * A USB function descriptor
 *
 * This is an internal descriptor used to represent an association of
 * interfaces within a USB device.
 */
struct usb_function_descriptor {
        /** Vendor ID */
        uint16_t vendor;
        /** Product ID */
        uint16_t product;
        /** Class */
        union usb_class_descriptor class;
        /** Number of interfaces */
        unsigned int count;
};

/**
 * A USB function
 *
 * A USB function represents an association of interfaces within a USB
 * device.
 */
struct usb_function {
        /** Name */
        const char *name;
        /** USB device */
        struct usb_device *usb;
        /** Function descriptor */
        struct usb_function_descriptor desc;
        /** Generic device */
        struct device dev;
        /** List of functions within this USB device */
        struct list_head list;

        /** Driver */
        struct usb_driver *driver;
        /** Driver private data */
        void *priv;
        /** Driver device ID */
        struct usb_device_id *id;

        /** List of interface numbers
         *
         * This must be the last field within the structure.
         */
        uint8_t interface[0];
};

/**
 * Set USB function driver private data
 *
 * @v func              USB function
 * @v priv              Driver private data
 */
static inline __attribute__ (( always_inline )) void
usb_func_set_drvdata ( struct usb_function *func, void *priv ) {
        func->priv = priv;
}

/**
 * Get USB function driver private data
 *
 * @v function          USB function
 * @ret priv            Driver private data
 */
static inline __attribute__ (( always_inline )) void *
usb_func_get_drvdata ( struct usb_function *func ) {
        return func->priv;
}

/** A USB device */
struct usb_device {
        /** Name */
        char name[32];
        /** USB port */
        struct usb_port *port;
        /** Device speed */
        unsigned int speed;
        /** List of devices on this bus */
        struct list_head list;
        /** Device address, if assigned */
        unsigned int address;
        /** Device descriptor */
        struct usb_device_descriptor device;
        /** List of functions */
        struct list_head functions;

        /** Host controller operations */
        struct usb_device_host_operations *host;
        /** Host controller private data */
        void *priv;

        /** Endpoint list */
        struct usb_endpoint *ep[32];

        /** Control endpoint */
        struct usb_endpoint control;
        /** Completed control transfers */
        struct list_head complete;

        /** Default language ID (if known) */
        unsigned int language;
};

/** USB device host controller operations */
struct usb_device_host_operations {
        /** Open device
         *
         * @v usb               USB device
         * @ret rc              Return status code
         */
        int ( * open ) ( struct usb_device *usb );
        /** Close device
         *
         * @v usb               USB device
         */
        void ( * close ) ( struct usb_device *usb );
        /** Assign device address
         *
         * @v usb               USB device
         * @ret rc              Return status code
         */
        int ( * address ) ( struct usb_device *usb );
};

/**
 * Set USB device host controller private data
 *
 * @v usb               USB device
 * @v priv              Host controller private data
 */
static inline __attribute__ (( always_inline )) void
usb_set_hostdata ( struct usb_device *usb, void *priv ) {
        usb->priv = priv;
}

/**
 * Get USB device host controller private data
 *
 * @v usb               USB device
 * @ret priv            Host controller private data
 */
static inline __attribute__ (( always_inline )) void *
usb_get_hostdata ( struct usb_device *usb ) {
        return usb->priv;
}

/**
 * Get USB endpoint
 *
 * @v usb               USB device
 * @v address           Endpoint address
 * @ret ep              USB endpoint, or NULL if not opened
 */
static inline struct usb_endpoint * usb_endpoint ( struct usb_device *usb,
                                                   unsigned int address ) {

        return usb->ep[ USB_ENDPOINT_IDX ( address ) ];
}

/** A USB port */
struct usb_port {
        /** USB hub */
        struct usb_hub *hub;
        /** Port address */
        unsigned int address;
        /** Port protocol */
        unsigned int protocol;
        /** Port speed */
        unsigned int speed;
        /** Port disconnection has been detected
         *
         * This should be set whenever the underlying hardware reports
         * a connection status change.
         */
        int disconnected;
        /** Port has an attached device */
        int attached;
        /** Currently attached device (if in use)
         *
         * Note that this field will be NULL if the attached device
         * has been freed (e.g. because there were no drivers found).
         */
        struct usb_device *usb;
        /** List of changed ports */
        struct list_head changed;
};

/** A USB hub */
struct usb_hub {
        /** Name */
        const char *name;
        /** USB bus */
        struct usb_bus *bus;
        /** Underlying USB device, if any */
        struct usb_device *usb;
        /** Hub protocol */
        unsigned int protocol;
        /** Number of ports */
        unsigned int ports;

        /** List of hubs */
        struct list_head list;

        /** Host controller operations */
        struct usb_hub_host_operations *host;
        /** Driver operations */
        struct usb_hub_driver_operations *driver;
        /** Driver private data */
        void *priv;

        /** Port list
         *
         * This must be the last field within the structure.
         */
        struct usb_port port[0];
};

/** USB hub host controller operations */
struct usb_hub_host_operations {
        /** Open hub
         *
         * @v hub               USB hub
         * @ret rc              Return status code
         */
        int ( * open ) ( struct usb_hub *hub );
        /** Close hub
         *
         * @v hub               USB hub
         */
        void ( * close ) ( struct usb_hub *hub );
};

/** USB hub driver operations */
struct usb_hub_driver_operations {
        /** Open hub
         *
         * @v hub               USB hub
         * @ret rc              Return status code
         */
        int ( * open ) ( struct usb_hub *hub );
        /** Close hub
         *
         * @v hub               USB hub
         */
        void ( * close ) ( struct usb_hub *hub );
        /** Enable port
         *
         * @v hub               USB hub
         * @v port              USB port
         * @ret rc              Return status code
         */
        int ( * enable ) ( struct usb_hub *hub, struct usb_port *port );
        /** Disable port
         *
         * @v hub               USB hub
         * @v port              USB port
         * @ret rc              Return status code
         */
        int ( * disable ) ( struct usb_hub *hub, struct usb_port *port );
        /** Update port speed
         *
         * @v hub               USB hub
         * @v port              USB port
         * @ret rc              Return status code
         */
        int ( * speed ) ( struct usb_hub *hub, struct usb_port *port );
        /** Clear transaction translator buffer
         *
         * @v hub               USB hub
         * @v port              USB port
         * @v ep                USB endpoint
         * @ret rc              Return status code
         */
        int ( * clear_tt ) ( struct usb_hub *hub, struct usb_port *port,
                             struct usb_endpoint *ep );
};

/**
 * Set USB hub driver private data
 *
 * @v hub               USB hub
 * @v priv              Driver private data
 */
static inline __attribute__ (( always_inline )) void
usb_hub_set_drvdata ( struct usb_hub *hub, void *priv ) {
        hub->priv = priv;
}

/**
 * Get USB hub driver private data
 *
 * @v hub               USB hub
 * @ret priv            Driver private data
 */
static inline __attribute__ (( always_inline )) void *
usb_hub_get_drvdata ( struct usb_hub *hub ) {
        return hub->priv;
}

/**
 * Get USB port
 *
 * @v hub               USB hub
 * @v address           Port address
 * @ret port            USB port
 */
static inline __attribute__ (( always_inline )) struct usb_port *
usb_port ( struct usb_hub *hub, unsigned int address ) {

        return &hub->port[ address - 1 ];
}

/** A USB bus */
struct usb_bus {
        /** Name */
        const char *name;
        /** Underlying hardware device */
        struct device *dev;
        /** Host controller operations set */
        struct usb_host_operations *op;

        /** Bus address
         *
         * This is an internal index used only to allow a USB device
         * to be identified via a nominal bus:device address.
         */
        unsigned int address;
        /** Largest transfer allowed on the bus */
        size_t mtu;
        /** Address in-use mask
         *
         * This is used only by buses which perform manual address
         * assignment.  USB allows for addresses in the range [1,127].
         * We use a simple bitmask which restricts us to the range
         * [1,64]; this is unlikely to be a problem in practice.  For
         * comparison: controllers which perform autonomous address
         * assignment (such as xHCI) typically allow for only 32
         * devices per bus anyway.
         */
        unsigned long long addresses;

        /** Root hub */
        struct usb_hub *hub;

        /** List of USB buses */
        struct list_head list;
        /** List of devices */
        struct list_head devices;
        /** List of hubs */
        struct list_head hubs;

        /** Host controller operations */
        struct usb_bus_host_operations *host;
        /** Host controller private data */
        void *priv;
};

/** USB bus host controller operations */
struct usb_bus_host_operations {
        /** Open bus
         *
         * @v bus               USB bus
         * @ret rc              Return status code
         */
        int ( * open ) ( struct usb_bus *bus );
        /** Close bus
         *
         * @v bus               USB bus
         */
        void ( * close ) ( struct usb_bus *bus );
        /** Poll bus
         *
         * @v bus               USB bus
         */
        void ( * poll ) ( struct usb_bus *bus );
};

/** USB host controller operations */
struct usb_host_operations {
        /** Endpoint operations */
        struct usb_endpoint_host_operations endpoint;
        /** Device operations */
        struct usb_device_host_operations device;
        /** Bus operations */
        struct usb_bus_host_operations bus;
        /** Hub operations */
        struct usb_hub_host_operations hub;
        /** Root hub operations */
        struct usb_hub_driver_operations root;
};

/**
 * Set USB bus host controller private data
 *
 * @v bus               USB bus
 * @v priv              Host controller private data
 */
static inline __attribute__ (( always_inline )) void
usb_bus_set_hostdata ( struct usb_bus *bus, void *priv ) {
        bus->priv = priv;
}

/**
 * Get USB bus host controller private data
 *
 * @v bus               USB bus
 * @ret priv            Host controller private data
 */
static inline __attribute__ (( always_inline )) void *
usb_bus_get_hostdata ( struct usb_bus *bus ) {
        return bus->priv;
}

/**
 * Poll USB bus
 *
 * @v bus               USB bus
 */
static inline __attribute__ (( always_inline )) void
usb_poll ( struct usb_bus *bus ) {
        bus->host->poll ( bus );
}

/** Iterate over all USB buses */
#define for_each_usb_bus( bus ) \
        list_for_each_entry ( (bus), &usb_buses, list )

/**
 * Complete transfer (without error)
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 */
static inline __attribute__ (( always_inline )) void
usb_complete ( struct usb_endpoint *ep, struct io_buffer *iobuf ) {
        usb_complete_err ( ep, iobuf, 0 );
}

extern int usb_control ( struct usb_device *usb, unsigned int request,
                         unsigned int value, unsigned int index, void *data,
                         size_t len );
extern int usb_get_string_descriptor ( struct usb_device *usb,
                                       unsigned int index,
                                       unsigned int language,
                                       char *buf, size_t len );

/**
 * Get status
 *
 * @v usb               USB device
 * @v type              Request type
 * @v index             Target index
 * @v data              Status to fill in
 * @v len               Length of status descriptor
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_get_status ( struct usb_device *usb, unsigned int type, unsigned int index,
                 void *data, size_t len ) {

        return usb_control ( usb, ( USB_GET_STATUS | type ), 0, index,
                             data, len );
}

/**
 * Clear feature
 *
 * @v usb               USB device
 * @v type              Request type
 * @v feature           Feature selector
 * @v index             Target index
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_clear_feature ( struct usb_device *usb, unsigned int type,
                    unsigned int feature, unsigned int index ) {

        return usb_control ( usb, ( USB_CLEAR_FEATURE | type ),
                             feature, index, NULL, 0 );
}

/**
 * Set feature
 *
 * @v usb               USB device
 * @v type              Request type
 * @v feature           Feature selector
 * @v index             Target index
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_set_feature ( struct usb_device *usb, unsigned int type,
                  unsigned int feature, unsigned int index ) {

        return usb_control ( usb, ( USB_SET_FEATURE | type ),
                             feature, index, NULL, 0 );
}

/**
 * Set address
 *
 * @v usb               USB device
 * @v address           Device address
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_set_address ( struct usb_device *usb, unsigned int address ) {

        return usb_control ( usb, USB_SET_ADDRESS, address, 0, NULL, 0 );
}

/**
 * Get USB descriptor
 *
 * @v usb               USB device
 * @v type              Request type
 * @v desc              Descriptor type
 * @v index             Descriptor index
 * @v language          Language ID (for string descriptors)
 * @v data              Descriptor to fill in
 * @v len               Maximum length of descriptor
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_get_descriptor ( struct usb_device *usb, unsigned int type,
                     unsigned int desc, unsigned int index,
                     unsigned int language, struct usb_descriptor_header *data,
                     size_t len ) {

        return usb_control ( usb, ( USB_GET_DESCRIPTOR | type ),
                             ( ( desc << 8 ) | index ), language, data, len );
}

/**
 * Get first part of USB device descriptor (up to and including MTU)
 *
 * @v usb               USB device
 * @v data              Device descriptor to (partially) fill in
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_get_mtu ( struct usb_device *usb, struct usb_device_descriptor *data ) {

        return usb_get_descriptor ( usb, 0, USB_DEVICE_DESCRIPTOR, 0, 0,
                                    &data->header,
                                    ( offsetof ( typeof ( *data ), mtu ) +
                                      sizeof ( data->mtu ) ) );
}

/**
 * Get USB device descriptor
 *
 * @v usb               USB device
 * @v data              Device descriptor to fill in
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_get_device_descriptor ( struct usb_device *usb,
                            struct usb_device_descriptor *data ) {

        return usb_get_descriptor ( usb, 0, USB_DEVICE_DESCRIPTOR, 0, 0,
                                    &data->header, sizeof ( *data ) );
}

/**
 * Get USB configuration descriptor
 *
 * @v usb               USB device
 * @v index             Configuration index
 * @v data              Configuration descriptor to fill in
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_get_config_descriptor ( struct usb_device *usb, unsigned int index,
                            struct usb_configuration_descriptor *data,
                            size_t len ) {

        return usb_get_descriptor ( usb, 0, USB_CONFIGURATION_DESCRIPTOR, index,
                                    0, &data->header, len );
}

/**
 * Set USB configuration
 *
 * @v usb               USB device
 * @v index             Configuration index
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_set_configuration ( struct usb_device *usb, unsigned int index ) {

        return usb_control ( usb, USB_SET_CONFIGURATION, index, 0, NULL, 0 );
}

/**
 * Set USB interface alternate setting
 *
 * @v usb               USB device
 * @v interface         Interface number
 * @v alternate         Alternate setting
 * @ret rc              Return status code
 */
static inline __attribute__ (( always_inline )) int
usb_set_interface ( struct usb_device *usb, unsigned int interface,
                    unsigned int alternate ) {

        return usb_control ( usb, USB_SET_INTERFACE, alternate, interface,
                             NULL, 0 );
}

/**
 * Get USB depth
 *
 * @v usb               USB device
 * @ret depth           Hub depth
 */
static inline unsigned int usb_depth ( struct usb_device *usb ) {
        struct usb_device *parent;
        unsigned int depth;

        /* Navigate up to root hub, constructing depth as we go */
        for ( depth = 0 ; ( parent = usb->port->hub->usb ) ; usb = parent )
                depth++;

        return depth;
}

extern struct list_head usb_buses;

extern struct usb_interface_descriptor *
usb_interface_descriptor ( struct usb_configuration_descriptor *config,
                           unsigned int interface, unsigned int alternate );
extern struct usb_endpoint_descriptor *
usb_endpoint_descriptor ( struct usb_configuration_descriptor *config,
                          struct usb_interface_descriptor *interface,
                          unsigned int type, unsigned int index );
extern struct usb_endpoint_companion_descriptor *
usb_endpoint_companion_descriptor ( struct usb_configuration_descriptor *config,
                                    struct usb_endpoint_descriptor *desc );

extern struct usb_device * find_usb ( struct usb_bus *bus,
                                      unsigned int address );

extern struct usb_hub * alloc_usb_hub ( struct usb_bus *bus,
                                        struct usb_device *usb,
                                        unsigned int ports,
                                        struct usb_hub_driver_operations *op );
extern int register_usb_hub ( struct usb_hub *hub );
extern void unregister_usb_hub ( struct usb_hub *hub );
extern void free_usb_hub ( struct usb_hub *hub );

extern void usb_port_changed ( struct usb_port *port );

extern struct usb_bus * alloc_usb_bus ( struct device *dev,
                                        unsigned int ports, size_t mtu,
                                        struct usb_host_operations *op );
extern int register_usb_bus ( struct usb_bus *bus );
extern void unregister_usb_bus ( struct usb_bus *bus );
extern void free_usb_bus ( struct usb_bus *bus );
extern struct usb_bus * find_usb_bus ( unsigned int address );
extern struct usb_bus * find_usb_bus_by_location ( unsigned int bus_type,
                                                   unsigned int location );

extern int usb_alloc_address ( struct usb_bus *bus );
extern void usb_free_address ( struct usb_bus *bus, unsigned int address );
extern int usb_find_next ( struct usb_device **usb, uint16_t *busdev );
extern unsigned int usb_route_string ( struct usb_device *usb );
extern struct usb_port * usb_root_hub_port ( struct usb_device *usb );
extern struct usb_port * usb_transaction_translator ( struct usb_device *usb );

/** Minimum reset time
 *
 * Section 7.1.7.5 of the USB2 specification states that root hub
 * ports should assert reset signalling for at least 50ms.
 */
#define USB_RESET_DELAY_MS 50

/** Reset recovery time
 *
 * Section 9.2.6.2 of the USB2 specification states that the
 * "recovery" interval after a port reset is 10ms.
 */
#define USB_RESET_RECOVER_DELAY_MS 10

/** Maximum time to wait for a control transaction to complete
 *
 * Section 9.2.6.1 of the USB2 specification states that the upper
 * limit for commands to be processed is 5 seconds.
 */
#define USB_CONTROL_MAX_WAIT_MS 5000

/** Set address recovery time
 *
 * Section 9.2.6.3 of the USB2 specification states that devices are
 * allowed a 2ms recovery interval after receiving a new address.
 */
#define USB_SET_ADDRESS_RECOVER_DELAY_MS 2

/** Time to wait for ports to stabilise
 *
 * Section 7.1.7.3 of the USB specification states that we must allow
 * 100ms for devices to signal attachment, and an additional 100ms for
 * connection debouncing.  (This delay is parallelised across all
 * ports on a hub; we do not delay separately for each port.)
 */
#define USB_PORT_DELAY_MS 200

/** A USB device ID */
struct usb_device_id {
        /** Name */
        const char *name;
        /** Vendor ID */
        uint16_t vendor;
        /** Product ID */
        uint16_t product;
        /** Arbitrary driver data */
        unsigned long driver_data;
};

/** Match-anything ID */
#define USB_ANY_ID 0xffff

/** A USB class ID */
struct usb_class_id {
        /** Class */
        union usb_class_descriptor class;
        /** Class mask */
        union usb_class_descriptor mask;
};

/** Construct USB class ID
 *
 * @v base              Base class code (or USB_ANY_ID)
 * @v subclass          Subclass code (or USB_ANY_ID)
 * @v protocol          Protocol code (or USB_ANY_ID)
 */
#define USB_CLASS_ID( base, subclass, protocol ) {                      \
        .class = {                                                      \
                .class = {                                              \
                        ( (base) & 0xff ),                              \
                        ( (subclass) & 0xff ),                          \
                        ( (protocol) & 0xff ),                          \
                },                                                      \
        },                                                              \
        .mask = {                                                       \
                .class = {                                              \
                        ( ( (base) == USB_ANY_ID ) ? 0x00 : 0xff ),     \
                        ( ( (subclass) == USB_ANY_ID ) ? 0x00 : 0xff ), \
                        ( ( (protocol) == USB_ANY_ID ) ? 0x00 : 0xff ), \
                },                                                      \
                },                                                      \
        }

/** A USB driver */
struct usb_driver {
        /** USB ID table */
        struct usb_device_id *ids;
        /** Number of entries in ID table */
        unsigned int id_count;
        /** Class ID */
        struct usb_class_id class;
        /** Driver score
         *
         * This is used to determine the preferred configuration for a
         * USB device.
         */
        unsigned int score;
        /**
         * Probe device
         *
         * @v func              USB function
         * @v config            Configuration descriptor
         * @ret rc              Return status code
         */
        int ( * probe ) ( struct usb_function *func,
                          struct usb_configuration_descriptor *config );
        /**
         * Remove device
         *
         * @v func              USB function
         */
        void ( * remove ) ( struct usb_function *func );
};

/** USB driver table */
#define USB_DRIVERS __table ( struct usb_driver, "usb_drivers" )

/** Declare a USB driver */
#define __usb_driver __table_entry ( USB_DRIVERS, 01 )

/** Declare a USB fallback driver */
#define __usb_fallback_driver __table_entry ( USB_DRIVERS, 02 )

/** USB driver scores */
enum usb_driver_score {
        /** Fallback driver (has no effect on overall score) */
        USB_SCORE_FALLBACK = 0,
        /** Deprecated driver */
        USB_SCORE_DEPRECATED = 1,
        /** Normal driver */
        USB_SCORE_NORMAL = 2,
};

extern struct usb_driver *
usb_find_driver ( struct usb_function_descriptor *desc,
                  struct usb_device_id **id );

#endif /* _IPXE_USB_H */