dummy_hcd.c

h内核

/*
 * dummy_hcd.c -- Dummy/Loopback USB host and device emulator driver.
 *
 * Maintainer: Alan Stern <[e-mail]>
 *
 * Copyright (C) 2003 David Brownell
 * Copyright (C) 2003, 2004 Alan Stern
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


/*
 * This exposes a device side "USB gadget" API, driven by requests to a
 * Linux-USB host controller driver.  USB traffic is simulated; there's
 * no need for USB hardware.  Use this with two other drivers:
 *
 *  - Gadget driver, responding to requests (slave);
 *  - Host-side device driver, as already familiar in Linux.
 *
 * Having this all in one kernel can help some stages of development,
 * bypassing some hardware (and driver) issues.  UML could help too.
 */

#define DEBUG

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/version.h>

#include <linux/usb.h>
#include <linux/usb_gadget.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/unaligned.h>


#include "../core/hcd.h"


#define DRIVER_DESC	"USB Host+Gadget Emulator"
#define DRIVER_VERSION	"17 Dec 2004"

static const char	driver_name [] = "dummy_hcd";
static const char	driver_desc [] = "USB Host+Gadget Emulator";

static const char	gadget_name [] = "dummy_udc";

MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_AUTHOR ("David Brownell");
MODULE_LICENSE ("GPL");

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

/* gadget side driver data structres */
struct dummy_ep {
	struct list_head		queue;
	unsigned long			last_io;	/* jiffies timestamp */
	struct usb_gadget		*gadget;
	const struct usb_endpoint_descriptor *desc;
	struct usb_ep			ep;
	unsigned			halted : 1;
	unsigned			already_seen : 1;
	unsigned			setup_stage : 1;
};

struct dummy_request {
	struct list_head		queue;		/* ep's requests */
	struct usb_request		req;
};

static inline struct dummy_ep *usb_ep_to_dummy_ep (struct usb_ep *_ep)
{
	return container_of (_ep, struct dummy_ep, ep);
}

static inline struct dummy_request *usb_request_to_dummy_request
		(struct usb_request *_req)
{
	return container_of (_req, struct dummy_request, req);
}

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

/*
 * Every device has ep0 for control requests, plus up to 30 more endpoints,
 * in one of two types:
 *
 *   - Configurable:  direction (in/out), type (bulk, iso, etc), and endpoint
 *     number can be changed.  Names like "ep-a" are used for this type.
 *
 *   - Fixed Function:  in other cases.  some characteristics may be mutable;
 *     that'd be hardware-specific.  Names like "ep12out-bulk" are used.
 *
 * Gadget drivers are responsible for not setting up conflicting endpoint
 * configurations, illegal or unsupported packet lengths, and so on.
 */

static const char ep0name [] = "ep0";

static const char *const ep_name [] = {
	ep0name,				/* everyone has ep0 */

	/* act like a net2280: high speed, six configurable endpoints */
	"ep-a", "ep-b", "ep-c", "ep-d", "ep-e", "ep-f",

	/* or like pxa250: fifteen fixed function endpoints */
	"ep1in-bulk", "ep2out-bulk", "ep3in-iso", "ep4out-iso", "ep5in-int",
	"ep6in-bulk", "ep7out-bulk", "ep8in-iso", "ep9out-iso", "ep10in-int",
	"ep11in-bulk", "ep12out-bulk", "ep13in-iso", "ep14out-iso",
		"ep15in-int",

	/* or like sa1100: two fixed function endpoints */
	"ep1out-bulk", "ep2in-bulk",
};
#define DUMMY_ENDPOINTS	(sizeof(ep_name)/sizeof(char *))

#define FIFO_SIZE		64

struct urbp {
	struct urb		*urb;
	struct list_head	urbp_list;
};

struct dummy {
	spinlock_t			lock;

	/*
	 * SLAVE/GADGET side support
	 */
	struct dummy_ep			ep [DUMMY_ENDPOINTS];
	int				address;
	struct usb_gadget		gadget;
	struct usb_gadget_driver	*driver;
	struct dummy_request		fifo_req;
	u8				fifo_buf [FIFO_SIZE];
	u16				devstatus;

	/*
	 * MASTER/HOST side support
	 */
	struct timer_list		timer;
	u32				port_status;
	unsigned			started:1;
	unsigned			resuming:1;
	unsigned long			re_timeout;

	struct usb_device		*udev;
	struct list_head		urbp_list;
};

static inline struct dummy *hcd_to_dummy (struct usb_hcd *hcd)
{
	return (struct dummy *) (hcd->hcd_priv);
}

static inline struct usb_hcd *dummy_to_hcd (struct dummy *dum)
{
	return container_of((void *) dum, struct usb_hcd, hcd_priv);
}

static inline struct device *dummy_dev (struct dummy *dum)
{
	return dummy_to_hcd(dum)->self.controller;
}

static inline struct dummy *ep_to_dummy (struct dummy_ep *ep)
{
	return container_of (ep->gadget, struct dummy, gadget);
}

static inline struct dummy *gadget_to_dummy (struct usb_gadget *gadget)
{
	return container_of (gadget, struct dummy, gadget);
}

static inline struct dummy *gadget_dev_to_dummy (struct device *dev)
{
	return container_of (dev, struct dummy, gadget.dev);
}

static struct dummy			*the_controller;

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

/*
 * This "hardware" may look a bit odd in diagnostics since it's got both
 * host and device sides; and it binds different drivers to each side.
 */
static struct platform_device		the_pdev;

static struct device_driver dummy_driver = {
	.name		= (char *) driver_name,
	.bus		= &platform_bus_type,
};

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

/* SLAVE/GADGET SIDE DRIVER
 *
 * This only tracks gadget state.  All the work is done when the host
 * side tries some (emulated) i/o operation.  Real device controller
 * drivers would do real i/o using dma, fifos, irqs, timers, etc.
 */

#define is_enabled(dum) \
	(dum->port_status & USB_PORT_STAT_ENABLE)

static int
dummy_enable (struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
{
	struct dummy		*dum;
	struct dummy_ep		*ep;
	unsigned		max;
	int			retval;

	ep = usb_ep_to_dummy_ep (_ep);
	if (!_ep || !desc || ep->desc || _ep->name == ep0name
			|| desc->bDescriptorType != USB_DT_ENDPOINT)
		return -EINVAL;
	dum = ep_to_dummy (ep);
	if (!dum->driver || !is_enabled (dum))
		return -ESHUTDOWN;
	max = le16_to_cpu(desc->wMaxPacketSize) & 0x3ff;

	/* drivers must not request bad settings, since lower levels
	 * (hardware or its drivers) may not check.  some endpoints
	 * can't do iso, many have maxpacket limitations, etc.
	 *
	 * since this "hardware" driver is here to help debugging, we
	 * have some extra sanity checks.  (there could be more though,
	 * especially for "ep9out" style fixed function ones.)
	 */
	retval = -EINVAL;
	switch (desc->bmAttributes & 0x03) {
	case USB_ENDPOINT_XFER_BULK:
		if (strstr (ep->ep.name, "-iso")
				|| strstr (ep->ep.name, "-int")) {
			goto done;
		}
		switch (dum->gadget.speed) {
		case USB_SPEED_HIGH:
			if (max == 512)
				break;
			/* conserve return statements */
		default:
			switch (max) {
			case 8: case 16: case 32: case 64:
				/* we'll fake any legal size */
				break;
			default:
		case USB_SPEED_LOW:
				goto done;
			}
		}
		break;
	case USB_ENDPOINT_XFER_INT:
		if (strstr (ep->ep.name, "-iso")) /* bulk is ok */
			goto done;
		/* real hardware might not handle all packet sizes */
		switch (dum->gadget.speed) {
		case USB_SPEED_HIGH:
			if (max <= 1024)
				break;
			/* save a return statement */
		case USB_SPEED_FULL:
			if (max <= 64)
				break;
			/* save a return statement */
		default:
			if (max <= 8)
				break;
			goto done;
		}
		break;
	case USB_ENDPOINT_XFER_ISOC:
		if (strstr (ep->ep.name, "-bulk")
				|| strstr (ep->ep.name, "-int"))
			goto done;
		/* real hardware might not handle all packet sizes */
		switch (dum->gadget.speed) {
		case USB_SPEED_HIGH:
			if (max <= 1024)
				break;
			/* save a return statement */
		case USB_SPEED_FULL:
			if (max <= 1023)
				break;
			/* save a return statement */
		default:
			goto done;
		}
		break;
	default:
		/* few chips support control except on ep0 */
		goto done;
	}

	_ep->maxpacket = max;
	ep->desc = desc;

	dev_dbg (dummy_dev(dum), "enabled %s (ep%d%s-%s) maxpacket %d\n",
		_ep->name,
		desc->bEndpointAddress & 0x0f,
		(desc->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
		({ char *val;
		 switch (desc->bmAttributes & 0x03) {
		 case USB_ENDPOINT_XFER_BULK: val = "bulk"; break;
		 case USB_ENDPOINT_XFER_ISOC: val = "iso"; break;
		 case USB_ENDPOINT_XFER_INT: val = "intr"; break;
		 default: val = "ctrl"; break;
		 }; val; }),
		max);

	/* at this point real hardware should be NAKing transfers
	 * to that endpoint, until a buffer is queued to it.
	 */
	retval = 0;
done:
	return retval;
}

/* called with spinlock held */
static void nuke (struct dummy *dum, struct dummy_ep *ep)
{
	while (!list_empty (&ep->queue)) {
		struct dummy_request	*req;

		req = list_entry (ep->queue.next, struct dummy_request, queue);
		list_del_init (&req->queue);
		req->req.status = -ESHUTDOWN;

		spin_unlock (&dum->lock);
		req->req.complete (&ep->ep, &req->req);
		spin_lock (&dum->lock);
	}
}

static int dummy_disable (struct usb_ep *_ep)
{
	struct dummy_ep		*ep;
	struct dummy		*dum;
	unsigned long		flags;
	int			retval;

	ep = usb_ep_to_dummy_ep (_ep);
	if (!_ep || !ep->desc || _ep->name == ep0name)
		return -EINVAL;
	dum = ep_to_dummy (ep);

	spin_lock_irqsave (&dum->lock, flags);
	ep->desc = NULL;
	retval = 0;
	nuke (dum, ep);
	spin_unlock_irqrestore (&dum->lock, flags);

	dev_dbg (dummy_dev(dum), "disabled %s\n", _ep->name);
	return retval;
}

static struct usb_request *
dummy_alloc_request (struct usb_ep *_ep, int mem_flags)
{
	struct dummy_ep		*ep;
	struct dummy_request	*req;

	if (!_ep)
		return NULL;
	ep = usb_ep_to_dummy_ep (_ep);

	req = kmalloc (sizeof *req, mem_flags);
	if (!req)
		return NULL;
	memset (req, 0, sizeof *req);
	INIT_LIST_HEAD (&req->queue);
	return &req->req;
}

static void
dummy_free_request (struct usb_ep *_ep, struct usb_request *_req)
{
	struct dummy_ep		*ep;
	struct dummy_request	*req;

	ep = usb_ep_to_dummy_ep (_ep);
	if (!ep || !_req || (!ep->desc && _ep->name != ep0name))
		return;

	req = usb_request_to_dummy_request (_req);
	WARN_ON (!list_empty (&req->queue));
	kfree (req);
}

static void *
dummy_alloc_buffer (
	struct usb_ep *_ep,
	unsigned bytes,
	dma_addr_t *dma,
	int mem_flags
) {
	char			*retval;
	struct dummy_ep		*ep;
	struct dummy		*dum;

	ep = usb_ep_to_dummy_ep (_ep);
	dum = ep_to_dummy (ep);

	if (!dum->driver)
		return NULL;
	retval = kmalloc (bytes, mem_flags);
	*dma = (dma_addr_t) retval;
	return retval;
}

static void
dummy_free_buffer (
	struct usb_ep *_ep,
	void *buf,
	dma_addr_t dma,
	unsigned bytes
) {
	if (bytes)
		kfree (buf);
}

static void
fifo_complete (struct usb_ep *ep, struct usb_request *req)
{
}

static int
dummy_queue (struct usb_ep *_ep, struct usb_request *_req, int mem_flags)
{
	struct dummy_ep		*ep;
	struct dummy_request	*req;
	struct dummy		*dum;
	unsigned long		flags;

	req = usb_request_to_dummy_request (_req);
	if (!_req || !list_empty (&req->queue) || !_req->complete)
		return -EINVAL;

	ep = usb_ep_to_dummy_ep (_ep);
	if (!_ep || (!ep->desc && _ep->name != ep0name))
		return -EINVAL;

	dum = ep_to_dummy (ep);
	if (!dum->driver || !is_enabled (dum))
		return -ESHUTDOWN;

#if 0
	dev_dbg (dummy_dev(dum), "ep %p queue req %p to %s, len %d buf %p\n",
			ep, _req, _ep->name, _req->length, _req->buf);
#endif

	_req->status = -EINPROGRESS;
	_req->actual = 0;
	spin_lock_irqsave (&dum->lock, flags);

	/* implement an emulated single-request FIFO */
	if (ep->desc && (ep->desc->bEndpointAddress & USB_DIR_IN) &&
			list_empty (&dum->fifo_req.queue) &&
			list_empty (&ep->queue) &&
			_req->length <= FIFO_SIZE) {
		req = &dum->fifo_req;
		req->req = *_req;
		req->req.buf = dum->fifo_buf;
		memcpy (dum->fifo_buf, _req->buf, _req->length);
		req->req.context = dum;
		req->req.complete = fifo_complete;

		spin_unlock (&dum->lock);
		_req->actual = _req->length;
		_req->status = 0;
		_req->complete (_ep, _req);
		spin_lock (&dum->lock);
	}
	list_add_tail (&req->queue, &ep->queue);
	spin_unlock_irqrestore (&dum->lock, flags);

	/* real hardware would likely enable transfers here, in case
	 * it'd been left NAKing.
	 */
	return 0;
}

static int dummy_dequeue (struct usb_ep *_ep, struct usb_request *_req)
{
	struct dummy_ep		*ep;
	struct dummy		*dum;
	int			retval = -EINVAL;
	unsigned long		flags;
	struct dummy_request	*req = NULL;

	if (!_ep || !_req)
		return retval;
	ep = usb_ep_to_dummy_ep (_ep);
	dum = ep_to_dummy (ep);

	if (!dum->driver)
		return -ESHUTDOWN;

	spin_lock_irqsave (&dum->lock, flags);
	list_for_each_entry (req, &ep->queue, queue) {
		if (&req->req == _req) {
			list_del_init (&req->queue);
			_req->status = -ECONNRESET;
			retval = 0;
			break;
		}
	}
	spin_unlock_irqrestore (&dum->lock, flags);

	if (retval == 0) {
		dev_dbg (dummy_dev(dum),
				"dequeued req %p from %s, len %d buf %p\n",
				req, _ep->name, _req->length, _req->buf);
		_req->complete (_ep, _req);
	}
	return retval;
}

static int
dummy_set_halt (struct usb_ep *_ep, int value)
{
	struct dummy_ep		*ep;
	struct dummy		*dum;

	if (!_ep)
		return -EINVAL;
	ep = usb_ep_to_dummy_ep (_ep);
	dum = ep_to_dummy (ep);
	if (!dum->driver)
		return -ESHUTDOWN;
	if (!value)
		ep->halted = 0;
	else if (ep->desc && (ep->desc->bEndpointAddress & USB_DIR_IN) &&
			!list_empty (&ep->queue))
		return -EAGAIN;
	else
		ep->halted = 1;
	/* FIXME clear emulated data toggle too */
	return 0;
}

static const struct usb_ep_ops dummy_ep_ops = {
	.enable		= dummy_enable,
	.disable	= dummy_disable,

	.alloc_request	= dummy_alloc_request,
	.free_request	= dummy_free_request,

	.alloc_buffer	= dummy_alloc_buffer,
	.free_buffer	= dummy_free_buffer,
	/* map, unmap, ... eventually hook the "generic" dma calls */

	.queue		= dummy_queue,
	.dequeue	= dummy_dequeue,

	.set_halt	= dummy_set_halt,
};

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

/* there are both host and device side versions of this call ... */
static int dummy_g_get_frame (struct usb_gadget *_gadget)
{
	struct timeval	tv;

	do_gettimeofday (&tv);
	return tv.tv_usec / 1000;
}

static int dummy_wakeup (struct usb_gadget *_gadget)
{
	struct dummy	*dum;

	dum = gadget_to_dummy (_gadget);
	if ((dum->devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) == 0
			|| !(dum->port_status & (1 << USB_PORT_FEAT_SUSPEND)))
		return -EINVAL;

	/* hub notices our request, issues downstream resume, etc */
	dum->resuming = 1;
	dum->port_status |= (1 << USB_PORT_FEAT_C_SUSPEND);
	return 0;
}