hcd.c

来自「linux 内核源代码」· C语言 代码 · 共 1,882 行 · 第 1/4 页

	/* ENDPOINT REQUESTS */

	case EndpointRequest | USB_REQ_GET_STATUS:
		// ENDPOINT_HALT flag
		tbuf [0] = 0;
		tbuf [1] = 0;
		len = 2;
			/* FALLTHROUGH */
	case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
	case EndpointOutRequest | USB_REQ_SET_FEATURE:
		dev_dbg (hcd->self.controller, "no endpoint features yet\n");
		break;

	/* CLASS REQUESTS (and errors) */

	default:
		/* non-generic request */
		switch (typeReq) {
		case GetHubStatus:
		case GetPortStatus:
			len = 4;
			break;
		case GetHubDescriptor:
			len = sizeof (struct usb_hub_descriptor);
			break;
		}
		status = hcd->driver->hub_control (hcd,
			typeReq, wValue, wIndex,
			tbuf, wLength);
		break;
error:
		/* "protocol stall" on error */
		status = -EPIPE;
	}

	if (status) {
		len = 0;
		if (status != -EPIPE) {
			dev_dbg (hcd->self.controller,
				"CTRL: TypeReq=0x%x val=0x%x "
				"idx=0x%x len=%d ==> %d\n",
				typeReq, wValue, wIndex,
				wLength, status);
		}
	}
	if (len) {
		if (urb->transfer_buffer_length < len)
			len = urb->transfer_buffer_length;
		urb->actual_length = len;
		// always USB_DIR_IN, toward host
		memcpy (ubuf, bufp, len);

		/* report whether RH hardware supports remote wakeup */
		if (patch_wakeup &&
				len > offsetof (struct usb_config_descriptor,
						bmAttributes))
			((struct usb_config_descriptor *)ubuf)->bmAttributes
				|= USB_CONFIG_ATT_WAKEUP;
	}

	/* any errors get returned through the urb completion */
	spin_lock_irq(&hcd_root_hub_lock);
	usb_hcd_unlink_urb_from_ep(hcd, urb);

	/* This peculiar use of spinlocks echoes what real HC drivers do.
	 * Avoiding calls to local_irq_disable/enable makes the code
	 * RT-friendly.
	 */
	spin_unlock(&hcd_root_hub_lock);
	usb_hcd_giveback_urb(hcd, urb, status);
	spin_lock(&hcd_root_hub_lock);

	spin_unlock_irq(&hcd_root_hub_lock);
	return 0;
}

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

/*
 * Root Hub interrupt transfers are polled using a timer if the
 * driver requests it; otherwise the driver is responsible for
 * calling usb_hcd_poll_rh_status() when an event occurs.
 *
 * Completions are called in_interrupt(), but they may or may not
 * be in_irq().
 */
void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
{
	struct urb	*urb;
	int		length;
	unsigned long	flags;
	char		buffer[4];	/* Any root hubs with > 31 ports? */

	if (unlikely(!hcd->rh_registered))
		return;
	if (!hcd->uses_new_polling && !hcd->status_urb)
		return;

	length = hcd->driver->hub_status_data(hcd, buffer);
	if (length > 0) {

		/* try to complete the status urb */
		spin_lock_irqsave(&hcd_root_hub_lock, flags);
		urb = hcd->status_urb;
		if (urb) {
			hcd->poll_pending = 0;
			hcd->status_urb = NULL;
			urb->actual_length = length;
			memcpy(urb->transfer_buffer, buffer, length);

			usb_hcd_unlink_urb_from_ep(hcd, urb);
			spin_unlock(&hcd_root_hub_lock);
			usb_hcd_giveback_urb(hcd, urb, 0);
			spin_lock(&hcd_root_hub_lock);
		} else {
			length = 0;
			hcd->poll_pending = 1;
		}
		spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
	}

	/* The USB 2.0 spec says 256 ms.  This is close enough and won't
	 * exceed that limit if HZ is 100. The math is more clunky than
	 * maybe expected, this is to make sure that all timers for USB devices
	 * fire at the same time to give the CPU a break inbetween */
	if (hcd->uses_new_polling ? hcd->poll_rh :
			(length == 0 && hcd->status_urb != NULL))
		mod_timer (&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
}
EXPORT_SYMBOL_GPL(usb_hcd_poll_rh_status);

/* timer callback */
static void rh_timer_func (unsigned long _hcd)
{
	usb_hcd_poll_rh_status((struct usb_hcd *) _hcd);
}

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

static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
{
	int		retval;
	unsigned long	flags;
	int		len = 1 + (urb->dev->maxchild / 8);

	spin_lock_irqsave (&hcd_root_hub_lock, flags);
	if (hcd->status_urb || urb->transfer_buffer_length < len) {
		dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
		retval = -EINVAL;
		goto done;
	}

	retval = usb_hcd_link_urb_to_ep(hcd, urb);
	if (retval)
		goto done;

	hcd->status_urb = urb;
	urb->hcpriv = hcd;	/* indicate it's queued */
	if (!hcd->uses_new_polling)
		mod_timer(&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));

	/* If a status change has already occurred, report it ASAP */
	else if (hcd->poll_pending)
		mod_timer(&hcd->rh_timer, jiffies);
	retval = 0;
 done:
	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
	return retval;
}

static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
{
	if (usb_endpoint_xfer_int(&urb->ep->desc))
		return rh_queue_status (hcd, urb);
	if (usb_endpoint_xfer_control(&urb->ep->desc))
		return rh_call_control (hcd, urb);
	return -EINVAL;
}

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

/* Unlinks of root-hub control URBs are legal, but they don't do anything
 * since these URBs always execute synchronously.
 */
static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
	unsigned long	flags;
	int		rc;

	spin_lock_irqsave(&hcd_root_hub_lock, flags);
	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
	if (rc)
		goto done;

	if (usb_endpoint_num(&urb->ep->desc) == 0) {	/* Control URB */
		;	/* Do nothing */

	} else {				/* Status URB */
		if (!hcd->uses_new_polling)
			del_timer (&hcd->rh_timer);
		if (urb == hcd->status_urb) {
			hcd->status_urb = NULL;
			usb_hcd_unlink_urb_from_ep(hcd, urb);

			spin_unlock(&hcd_root_hub_lock);
			usb_hcd_giveback_urb(hcd, urb, status);
			spin_lock(&hcd_root_hub_lock);
		}
	}
 done:
	spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
	return rc;
}



/*
 * Show & store the current value of authorized_default
 */
static ssize_t usb_host_authorized_default_show(struct device *dev,
						struct device_attribute *attr,
						char *buf)
{
	struct usb_device *rh_usb_dev = to_usb_device(dev);
	struct usb_bus *usb_bus = rh_usb_dev->bus;
	struct usb_hcd *usb_hcd;

	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
		return -ENODEV;
	usb_hcd = bus_to_hcd(usb_bus);
	return snprintf(buf, PAGE_SIZE, "%u\n", usb_hcd->authorized_default);
}

static ssize_t usb_host_authorized_default_store(struct device *dev,
						 struct device_attribute *attr,
						 const char *buf, size_t size)
{
	ssize_t result;
	unsigned val;
	struct usb_device *rh_usb_dev = to_usb_device(dev);
	struct usb_bus *usb_bus = rh_usb_dev->bus;
	struct usb_hcd *usb_hcd;

	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
		return -ENODEV;
	usb_hcd = bus_to_hcd(usb_bus);
	result = sscanf(buf, "%u\n", &val);
	if (result == 1) {
		usb_hcd->authorized_default = val? 1 : 0;
		result = size;
	}
	else
		result = -EINVAL;
	return result;
}

static DEVICE_ATTR(authorized_default, 0644,
	    usb_host_authorized_default_show,
	    usb_host_authorized_default_store);


/* Group all the USB bus attributes */
static struct attribute *usb_bus_attrs[] = {
		&dev_attr_authorized_default.attr,
		NULL,
};

static struct attribute_group usb_bus_attr_group = {
	.name = NULL,	/* we want them in the same directory */
	.attrs = usb_bus_attrs,
};



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

static struct class *usb_host_class;

int usb_host_init(void)
{
	int retval = 0;

	usb_host_class = class_create(THIS_MODULE, "usb_host");
	if (IS_ERR(usb_host_class))
		retval = PTR_ERR(usb_host_class);
	return retval;
}

void usb_host_cleanup(void)
{
	class_destroy(usb_host_class);
}

/**
 * usb_bus_init - shared initialization code
 * @bus: the bus structure being initialized
 *
 * This code is used to initialize a usb_bus structure, memory for which is
 * separately managed.
 */
static void usb_bus_init (struct usb_bus *bus)
{
	memset (&bus->devmap, 0, sizeof(struct usb_devmap));

	bus->devnum_next = 1;

	bus->root_hub = NULL;
	bus->busnum = -1;
	bus->bandwidth_allocated = 0;
	bus->bandwidth_int_reqs  = 0;
	bus->bandwidth_isoc_reqs = 0;

	INIT_LIST_HEAD (&bus->bus_list);
}

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

/**
 * usb_register_bus - registers the USB host controller with the usb core
 * @bus: pointer to the bus to register
 * Context: !in_interrupt()
 *
 * Assigns a bus number, and links the controller into usbcore data
 * structures so that it can be seen by scanning the bus list.
 */
static int usb_register_bus(struct usb_bus *bus)
{
	int result = -E2BIG;
	int busnum;

	mutex_lock(&usb_bus_list_lock);
	busnum = find_next_zero_bit (busmap.busmap, USB_MAXBUS, 1);
	if (busnum >= USB_MAXBUS) {
		printk (KERN_ERR "%s: too many buses\n", usbcore_name);
		goto error_find_busnum;
	}
	set_bit (busnum, busmap.busmap);
	bus->busnum = busnum;
	bus->class_dev = class_device_create(usb_host_class, NULL, MKDEV(0,0),
					     bus->controller, "usb_host%d",
					     busnum);
	result = PTR_ERR(bus->class_dev);
	if (IS_ERR(bus->class_dev))
		goto error_create_class_dev;
	class_set_devdata(bus->class_dev, bus);

	/* Add it to the local list of buses */
	list_add (&bus->bus_list, &usb_bus_list);
	mutex_unlock(&usb_bus_list_lock);

	usb_notify_add_bus(bus);

	dev_info (bus->controller, "new USB bus registered, assigned bus "
		  "number %d\n", bus->busnum);
	return 0;

error_create_class_dev:
	clear_bit(busnum, busmap.busmap);
error_find_busnum:
	mutex_unlock(&usb_bus_list_lock);
	return result;
}

/**
 * usb_deregister_bus - deregisters the USB host controller
 * @bus: pointer to the bus to deregister
 * Context: !in_interrupt()
 *
 * Recycles the bus number, and unlinks the controller from usbcore data
 * structures so that it won't be seen by scanning the bus list.
 */
static void usb_deregister_bus (struct usb_bus *bus)
{
	dev_info (bus->controller, "USB bus %d deregistered\n", bus->busnum);

	/*
	 * NOTE: make sure that all the devices are removed by the
	 * controller code, as well as having it call this when cleaning
	 * itself up
	 */
	mutex_lock(&usb_bus_list_lock);
	list_del (&bus->bus_list);
	mutex_unlock(&usb_bus_list_lock);

	usb_notify_remove_bus(bus);

	clear_bit (bus->busnum, busmap.busmap);

	class_device_unregister(bus->class_dev);
}

/**
 * register_root_hub - called by usb_add_hcd() to register a root hub
 * @hcd: host controller for this root hub
 *
 * This function registers the root hub with the USB subsystem.  It sets up
 * the device properly in the device tree and then calls usb_new_device()
 * to register the usb device.  It also assigns the root hub's USB address
 * (always 1).
 */
static int register_root_hub(struct usb_hcd *hcd)
{
	struct device *parent_dev = hcd->self.controller;
	struct usb_device *usb_dev = hcd->self.root_hub;
	const int devnum = 1;
	int retval;

	usb_dev->devnum = devnum;
	usb_dev->bus->devnum_next = devnum + 1;
	memset (&usb_dev->bus->devmap.devicemap, 0,
			sizeof usb_dev->bus->devmap.devicemap);
	set_bit (devnum, usb_dev->bus->devmap.devicemap);
	usb_set_device_state(usb_dev, USB_STATE_ADDRESS);

	mutex_lock(&usb_bus_list_lock);

	usb_dev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
	retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE);
	if (retval != sizeof usb_dev->descriptor) {
		mutex_unlock(&usb_bus_list_lock);
		dev_dbg (parent_dev, "can't read %s device descriptor %d\n",
				usb_dev->dev.bus_id, retval);
		return (retval < 0) ? retval : -EMSGSIZE;
	}

	retval = usb_new_device (usb_dev);
	if (retval) {
		dev_err (parent_dev, "can't register root hub for %s, %d\n",
				usb_dev->dev.bus_id, retval);
	}
	mutex_unlock(&usb_bus_list_lock);

	if (retval == 0) {
		spin_lock_irq (&hcd_root_hub_lock);
		hcd->rh_registered = 1;
		spin_unlock_irq (&hcd_root_hub_lock);

		/* Did the HC die before the root hub was registered? */
		if (hcd->state == HC_STATE_HALT)
			usb_hc_died (hcd);	/* This time clean up */
	}

	return retval;
}

void usb_enable_root_hub_irq (struct usb_bus *bus)
{
	struct usb_hcd *hcd;

	hcd = container_of (bus, struct usb_hcd, self);
	if (hcd->driver->hub_irq_enable && hcd->state != HC_STATE_HALT)
		hcd->driver->hub_irq_enable (hcd);
}


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

/**
 * usb_calc_bus_time - approximate periodic transaction time in nanoseconds
 * @speed: from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
 * @is_input: true iff the transaction sends data to the host
 * @isoc: true for isochronous transactions, false for interrupt ones
 * @bytecount: how many bytes in the transaction.
 *
 * Returns approximate bus time in nanoseconds for a periodic transaction.
 * See USB 2.0 spec section 5.11.3; only periodic transfers need to be
 * scheduled in software, this function is only used for such scheduling.
 */
long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount)
{
	unsigned long	tmp;