Add USB device support

This patch adds support for USB devices. It uses
the Linux Kernel gadget API. Along with this patch
comes driver support for the Freescale (arc) USB OTG
Core and USB Device Firmware Update (DFU)
The serial gadget support is not working at the moment.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 348 insertions, 0 deletions

diff --git a/include/usb/composite.h b/include/usb/composite.h
new file mode 100644
index 0000000000..5f7a75dbe6
--- /dev/null
+++ b/include/usb/composite.h
@@ -0,0 +1,348 @@
+/*
+ * composite.h -- framework for usb gadgets which are composite devices
+ *
+ * Copyright (C) 2006-2008 David Brownell
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef	__LINUX_USB_COMPOSITE_H
+#define	__LINUX_USB_COMPOSITE_H
+
+/*
+ * This framework is an optional layer on top of the USB Gadget interface,
+ * making it easier to build (a) Composite devices, supporting multiple
+ * functions within any single configuration, and (b) Multi-configuration
+ * devices, also supporting multiple functions but without necessarily
+ * having more than one function per configuration.
+ *
+ * Example:  a device with a single configuration supporting both network
+ * link and mass storage functions is a composite device.  Those functions
+ * might alternatively be packaged in individual configurations, but in
+ * the composite model the host can use both functions at the same time.
+ */
+
+#include <usb/ch9.h>
+#include <usb/gadget.h>
+
+
+struct usb_configuration;
+
+/**
+ * struct usb_function - describes one function of a configuration
+ * @name: For diagnostics, identifies the function.
+ * @strings: tables of strings, keyed by identifiers assigned during bind()
+ *	and by language IDs provided in control requests
+ * @descriptors: Table of full (or low) speed descriptors, using interface and
+ *	string identifiers assigned during @bind().  If this pointer is null,
+ *	the function will not be available at full speed (or at low speed).
+ * @hs_descriptors: Table of high speed descriptors, using interface and
+ *	string identifiers assigned during @bind().  If this pointer is null,
+ *	the function will not be available at high speed.
+ * @config: assigned when @usb_add_function() is called; this is the
+ *	configuration with which this function is associated.
+ * @bind: Before the gadget can register, all of its functions bind() to the
+ *	available resources including string and interface identifiers used
+ *	in interface or class descriptors; endpoints; I/O buffers; and so on.
+ * @unbind: Reverses @bind; called as a side effect of unregistering the
+ *	driver which added this function.
+ * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
+ *	initialize usb_ep.driver data at this time (when it is used).
+ *	Note that setting an interface to its current altsetting resets
+ *	interface state, and that all interfaces have a disabled state.
+ * @get_alt: Returns the active altsetting.  If this is not provided,
+ *	then only altsetting zero is supported.
+ * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons
+ *	include host resetting or reconfiguring the gadget, and disconnection.
+ * @setup: Used for interface-specific control requests.
+ * @suspend: Notifies functions when the host stops sending USB traffic.
+ * @resume: Notifies functions when the host restarts USB traffic.
+ *
+ * A single USB function uses one or more interfaces, and should in most
+ * cases support operation at both full and high speeds.  Each function is
+ * associated by @usb_add_function() with a one configuration; that function
+ * causes @bind() to be called so resources can be allocated as part of
+ * setting up a gadget driver.  Those resources include endpoints, which
+ * should be allocated using @usb_ep_autoconfig().
+ *
+ * To support dual speed operation, a function driver provides descriptors
+ * for both high and full speed operation.  Except in rare cases that don't
+ * involve bulk endpoints, each speed needs different endpoint descriptors.
+ *
+ * Function drivers choose their own strategies for managing instance data.
+ * The simplest strategy just declares it "static', which means the function
+ * can only be activated once.  If the function needs to be exposed in more
+ * than one configuration at a given speed, it needs to support multiple
+ * usb_function structures (one for each configuration).
+ *
+ * A more complex strategy might encapsulate a @usb_function structure inside
+ * a driver-specific instance structure to allows multiple activations.  An
+ * example of multiple activations might be a CDC ACM function that supports
+ * two or more distinct instances within the same configuration, providing
+ * several independent logical data links to a USB host.
+ */
+struct usb_function {
+	const char			*name;
+	struct usb_gadget_strings	**strings;
+	struct usb_descriptor_header	**descriptors;
+	struct usb_descriptor_header	**hs_descriptors;
+
+	struct usb_configuration	*config;
+
+	/* REVISIT:  bind() functions can be marked __init, which
+	 * makes trouble for section mismatch analysis.  See if
+	 * we can't restructure things to avoid mismatching.
+	 * Related:  unbind() may kfree() but bind() won't...
+	 */
+
+	/* configuration management:  bind/unbind */
+	int			(*bind)(struct usb_configuration *,
+					struct usb_function *);
+	void			(*unbind)(struct usb_configuration *,
+					struct usb_function *);
+
+	/* runtime state management */
+	int			(*set_alt)(struct usb_function *,
+					unsigned interface, unsigned alt);
+	int			(*get_alt)(struct usb_function *,
+					unsigned interface);
+	void			(*disable)(struct usb_function *);
+	int			(*setup)(struct usb_function *,
+					const struct usb_ctrlrequest *);
+	void			(*suspend)(struct usb_function *);
+	void			(*resume)(struct usb_function *);
+
+	/* private: */
+	/* internals */
+	struct list_head		list;
+};
+
+int usb_add_function(struct usb_configuration *, struct usb_function *);
+
+int usb_function_deactivate(struct usb_function *);
+int usb_function_activate(struct usb_function *);
+
+int usb_interface_id(struct usb_configuration *, struct usb_function *);
+
+/**
+ * ep_choose - select descriptor endpoint at current device speed
+ * @g: gadget, connected and running at some speed
+ * @hs: descriptor to use for high speed operation
+ * @fs: descriptor to use for full or low speed operation
+ */
+static inline struct usb_endpoint_descriptor *
+ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
+		struct usb_endpoint_descriptor *fs)
+{
+	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
+		return hs;
+	return fs;
+}
+
+#define	MAX_CONFIG_INTERFACES		16	/* arbitrary; max 255 */
+
+/**
+ * struct usb_configuration - represents one gadget configuration
+ * @label: For diagnostics, describes the configuration.
+ * @strings: Tables of strings, keyed by identifiers assigned during @bind()
+ *	and by language IDs provided in control requests.
+ * @descriptors: Table of descriptors preceding all function descriptors.
+ *	Examples include OTG and vendor-specific descriptors.
+ * @bind: Called from @usb_add_config() to allocate resources unique to this
+ *	configuration and to call @usb_add_function() for each function used.
+ * @unbind: Reverses @bind; called as a side effect of unregistering the
+ *	driver which added this configuration.
+ * @setup: Used to delegate control requests that aren't handled by standard
+ *	device infrastructure or directed at a specific interface.
+ * @bConfigurationValue: Copied into configuration descriptor.
+ * @iConfiguration: Copied into configuration descriptor.
+ * @bmAttributes: Copied into configuration descriptor.
+ * @bMaxPower: Copied into configuration descriptor.
+ * @cdev: assigned by @usb_add_config() before calling @bind(); this is
+ *	the device associated with this configuration.
+ *
+ * Configurations are building blocks for gadget drivers structured around
+ * function drivers.  Simple USB gadgets require only one function and one
+ * configuration, and handle dual-speed hardware by always providing the same
+ * functionality.  Slightly more complex gadgets may have more than one
+ * single-function configuration at a given speed; or have configurations
+ * that only work at one speed.
+ *
+ * Composite devices are, by definition, ones with configurations which
+ * include more than one function.
+ *
+ * The lifecycle of a usb_configuration includes allocation, initialization
+ * of the fields described above, and calling @usb_add_config() to set up
+ * internal data and bind it to a specific device.  The configuration's
+ * @bind() method is then used to initialize all the functions and then
+ * call @usb_add_function() for them.
+ *
+ * Those functions would normally be independant of each other, but that's
+ * not mandatory.  CDC WMC devices are an example where functions often
+ * depend on other functions, with some functions subsidiary to others.
+ * Such interdependency may be managed in any way, so long as all of the
+ * descriptors complete by the time the composite driver returns from
+ * its bind() routine.
+ */
+struct usb_configuration {
+	const char			*label;
+	struct usb_gadget_strings	**strings;
+	const struct usb_descriptor_header **descriptors;
+
+	/* REVISIT:  bind() functions can be marked __init, which
+	 * makes trouble for section mismatch analysis.  See if
+	 * we can't restructure things to avoid mismatching...
+	 */
+
+	/* configuration management:  bind/unbind */
+	int			(*bind)(struct usb_configuration *);
+	void			(*unbind)(struct usb_configuration *);
+	int			(*setup)(struct usb_configuration *,
+					const struct usb_ctrlrequest *);
+
+	/* fields in the config descriptor */
+	u8			bConfigurationValue;
+	u8			iConfiguration;
+	u8			bmAttributes;
+	u8			bMaxPower;
+
+	struct usb_composite_dev	*cdev;
+
+	/* private: */
+	/* internals */
+	struct list_head	list;
+	struct list_head	functions;
+	u8			next_interface_id;
+	unsigned		highspeed:1;
+	unsigned		fullspeed:1;
+	struct usb_function	*interface[MAX_CONFIG_INTERFACES];
+};
+
+int usb_add_config(struct usb_composite_dev *,
+		struct usb_configuration *);
+
+/**
+ * struct usb_composite_driver - groups configurations into a gadget
+ * @name: For diagnostics, identifies the driver.
+ * @dev: Template descriptor for the device, including default device
+ *	identifiers.
+ * @strings: tables of strings, keyed by identifiers assigned during bind()
+ *	and language IDs provided in control requests
+ * @bind: (REQUIRED) Used to allocate resources that are shared across the
+ *	whole device, such as string IDs, and add its configurations using
+ *	@usb_add_config().  This may fail by returning a negative errno
+ *	value; it should return zero on successful initialization.
+ * @unbind: Reverses @bind(); called as a side effect of unregistering
+ *	this driver.
+ * @suspend: Notifies when the host stops sending USB traffic,
+ *	after function notifications
+ * @resume: Notifies configuration when the host restarts USB traffic,
+ *	before function notifications
+ *
+ * Devices default to reporting self powered operation.  Devices which rely
+ * on bus powered operation should report this in their @bind() method.
+ *
+ * Before returning from @bind, various fields in the template descriptor
+ * may be overridden.  These include the idVendor/idProduct/bcdDevice values
+ * normally to bind the appropriate host side driver, and the three strings
+ * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
+ * meaningful device identifiers.  (The strings will not be defined unless
+ * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
+ * is also reported, as defined by the underlying controller driver.
+ */
+struct usb_composite_driver {
+	const char				*name;
+	const struct usb_device_descriptor	*dev;
+	struct usb_gadget_strings		**strings;
+
+	/* REVISIT:  bind() functions can be marked __init, which
+	 * makes trouble for section mismatch analysis.  See if
+	 * we can't restructure things to avoid mismatching...
+	 */
+
+	int			(*bind)(struct usb_composite_dev *);
+	int			(*unbind)(struct usb_composite_dev *);
+
+	/* global suspend hooks */
+	void			(*suspend)(struct usb_composite_dev *);
+	void			(*resume)(struct usb_composite_dev *);
+};
+
+extern int usb_composite_register(struct usb_composite_driver *);
+extern void usb_composite_unregister(struct usb_composite_driver *);
+
+
+/**
+ * struct usb_composite_device - represents one composite usb gadget
+ * @gadget: read-only, abstracts the gadget's usb peripheral controller
+ * @req: used for control responses; buffer is pre-allocated
+ * @bufsiz: size of buffer pre-allocated in @req
+ * @config: the currently active configuration
+ *
+ * One of these devices is allocated and initialized before the
+ * associated device driver's bind() is called.
+ *
+ * OPEN ISSUE:  it appears that some WUSB devices will need to be
+ * built by combining a normal (wired) gadget with a wireless one.
+ * This revision of the gadget framework should probably try to make
+ * sure doing that won't hurt too much.
+ *
+ * One notion for how to handle Wireless USB devices involves:
+ * (a) a second gadget here, discovery mechanism TBD, but likely
+ *     needing separate "register/unregister WUSB gadget" calls;
+ * (b) updates to usb_gadget to include flags "is it wireless",
+ *     "is it wired", plus (presumably in a wrapper structure)
+ *     bandgroup and PHY info;
+ * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
+ *     wireless-specific parameters like maxburst and maxsequence;
+ * (d) configurations that are specific to wireless links;
+ * (e) function drivers that understand wireless configs and will
+ *     support wireless for (additional) function instances;
+ * (f) a function to support association setup (like CBAF), not
+ *     necessarily requiring a wireless adapter;
+ * (g) composite device setup that can create one or more wireless
+ *     configs, including appropriate association setup support;
+ * (h) more, TBD.
+ */
+struct usb_composite_dev {
+	struct usb_gadget		*gadget;
+	struct usb_request		*req;
+	unsigned			bufsiz;
+
+	struct usb_configuration	*config;
+
+	/* private: */
+	/* internals */
+	struct usb_device_descriptor	desc;
+	struct list_head		configs;
+	struct usb_composite_driver	*driver;
+	u8				next_string_id;
+
+	/* the gadget driver won't enable the data pullup
+	 * while the deactivation count is nonzero.
+	 */
+	unsigned			deactivations;
+};
+
+extern int usb_string_id(struct usb_composite_dev *c);
+
+/* messaging utils */
+#define DBG(d, fmt, args...)
+#define VDBG(d, fmt, args...)
+#define ERROR(d, fmt, args...)
+#define WARNING(d, fmt, args...)
+#define INFO(d, fmt, args...)
+
+#endif	/* __LINUX_USB_COMPOSITE_H */