[usb] Add basic support for USB devices

Signed-off-by: Michael Brown <mcb30@ipxe.org>

3 files changed, 1154 insertions, 1 deletions

diff --git a/src/include/ipxe/device.h b/src/include/ipxe/device.h
index fd17b252..03e29851 100644
--- a/src/include/ipxe/device.h
+++ b/src/include/ipxe/device.h
@@ -66,10 +66,13 @@ struct device_description {
 /** Hyper-V bus type */
 #define BUS_TYPE_HV 9
 
+/** USB bus type */
+#define BUS_TYPE_USB 10
+
 /** A hardware device */
 struct device {
 	/** Name */
-	char name[16];
+	char name[32];
 	/** Driver name */
 	const char *driver_name;
 	/** Device description */
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 94de8aeb..d84cd712 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -76,6 +76,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_pci		     ( ERRFILE_DRIVER | 0x00040000 )
 #define ERRFILE_linux		     ( ERRFILE_DRIVER | 0x00050000 )
 #define ERRFILE_pcivpd		     ( ERRFILE_DRIVER | 0x00060000 )
+#define ERRFILE_usb		     ( ERRFILE_DRIVER | 0x00070000 )
 
 #define ERRFILE_nvs		     ( ERRFILE_DRIVER | 0x00100000 )
 #define ERRFILE_spi		     ( ERRFILE_DRIVER | 0x00110000 )
diff --git a/src/include/ipxe/usb.h b/src/include/ipxe/usb.h
new file mode 100644
index 00000000..5faa8dc2
--- /dev/null
+++ b/src/include/ipxe/usb.h
@@ -0,0 +1,1149 @@
+#ifndef _IPXE_USB_H
+#define _IPXE_USB_H
+
+/** @file
+ *
+ * Universal Serial Bus (USB)
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#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 ),
+};
+
+/** A USB setup data packet */
+struct usb_setup_packet {
+	/** Request */
+	uint16_t request;
+	/** Value paramer */
+	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 )
+
+/** 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
+
+/** 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
+
+/** 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 endpoint (internal) type */
+#define USB_INTERRUPT ( USB_ENDPOINT_ATTR_INTERRUPT | USB_DIR_IN )
+
+/** 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;
+
+	/** Endpoint is open */
+	int open;
+	/** Current failure state (if any) */
+	int rc;
+
+	/** Host controller operations */
+	struct usb_endpoint_host_operations *host;
+	/** Host controller private data */
+	void *priv;
+	/** Driver operations */
+	struct usb_endpoint_driver_operations *driver;
+};
+
+/** 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 packet		Setup packet
+	 * @v iobuf		I/O buffer (if any)
+	 * @ret rc		Return status code
+	 */
+	int ( * message ) ( struct usb_endpoint *ep,
+			    struct usb_setup_packet *setup,
+			    struct io_buffer *iobuf );
+	/** Enqueue stream transfer
+	 *
+	 * @v ep		USB endpoint
+	 * @v iobuf		I/O buffer
+	 * @ret rc		Return status code
+	 */
+	int ( * stream ) ( struct usb_endpoint *ep,
+			   struct io_buffer *iobuf );
+};
+
+/** 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
+
+/** 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
+ */
+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 ) {
+
+	ep->address = address;
+	ep->attributes = attributes;
+	ep->mtu = mtu;
+	ep->burst = burst;
+}
+
+/**
+ * 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 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 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 );
+extern void usb_complete_err ( struct usb_endpoint *ep,
+			       struct io_buffer *iobuf, int rc );
+
+/**
+ * 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;
+	/** Class */
+	struct usb_class class;
+	/** Number of interfaces */
+	unsigned int count;
+	/** 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;
+
+	/** 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;
+	/** 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;
+};
+
+/** 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;
+	/** Currently attached device (if any) */
+	struct usb_device *usb;
+	/** List of changed ports */
+	struct list_head list;
+};
+
+/** 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;
+
+	/** 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 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 );
+};
+
+/**
+ * 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;
+
+	/** Root hub */
+	struct usb_hub *hub;
+
+	/** List of devices */
+	struct list_head devices;
+	/** List of hubs */
+	struct list_head hubs;
+	/** List of changed ports */
+	struct list_head changed;
+	/** Process */
+	struct process process;
+
+	/** 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;
+	/** Root hub operations */
+	struct usb_hub_driver_operations hub;
+};
+
+/**
+ * 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 );
+}
+
+/**
+ * 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 );
+}
+
+/**
+ * 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 config		Configuration value
+ * @ret rc		Return status code
+ */
+static inline __attribute__ (( always_inline )) int
+usb_set_configuration ( struct usb_device *usb, unsigned int config ) {
+
+	return usb_control ( usb, USB_SET_CONFIGURATION, config, 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 );
+}
+
+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_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,
+					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 unsigned int usb_route_string ( struct usb_device *usb );
+extern unsigned int usb_depth ( struct usb_device *usb );
+extern struct usb_port * usb_root_hub_port ( struct usb_device *usb );
+
+/** Maximum time to wait for a control transaction to complete
+ *
+ * This is a policy decision.
+ */
+#define USB_CONTROL_MAX_WAIT_MS 100
+
+/** Time to wait for ports to stabilise
+ *
+ * This is a policy decision.
+ */
+#define USB_PORT_DELAY_MS 100
+
+/** A USB device ID */
+struct usb_device_id {
+	/** Name */
+	const char *name;
+	/** Vendor ID */
+	uint16_t vendor;
+	/** Product ID */
+	uint16_t product;
+	/** Class */
+	struct usb_class class;
+};
+
+/** Match-anything ID */
+#define USB_ANY_ID 0xffff
+
+/** A USB driver */
+struct usb_driver {
+	/** USB ID table */
+	struct usb_device_id *ids;
+	/** Number of entries in ID table */
+	unsigned int id_count;
+	/**
+	 * 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 )
+
+#endif /* _IPXE_USB_H */