hc_simple.c

linux客户机函数定义的实际例子

/*-------------------------------------------------------------------------*/
/*-------------------------------------------------------------------------*
 * simple generic USB HCD frontend Version 0.9.5 (10/28/2001)
 * for embedded HCs (SL811HS)
 * 
 * USB URB handling, hci_ hcs_
 * URB queueing, qu_
 * Transfer scheduling, sh_
 * 
 *
 *-------------------------------------------------------------------------*
 * 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
 *
 *-------------------------------------------------------------------------*/

/* main lock for urb access */
static spinlock_t usb_urb_lock = SPIN_LOCK_UNLOCKED;

/*-------------------------------------------------------------------------*/
/*-------------------------------------------------------------------------*/
/* URB HCD API function layer
 * * * */

/***************************************************************************
 * Function Name : hcs_urb_queue
 *
 * This function initializes the urb status and length before queueing the 
 * urb. 
 *
 * Input:  hci = data structure for the host controller
 *         urb = USB request block data structure 
 *
 * Return: 0 
 **************************************************************************/
static inline int hcs_urb_queue (hci_t * hci, struct urb * urb)
{
	int i;

	DBGFUNC ("enter hcs_urb_queue\n");
	if (usb_pipeisoc (urb->pipe)) {
		DBGVERBOSE ("hcs_urb_queue: isoc pipe\n");
		for (i = 0; i < urb->number_of_packets; i++) {
			urb->iso_frame_desc[i].actual_length = 0;
			urb->iso_frame_desc[i].status = -EXDEV;
		}

		/* urb->next hack : 1 .. resub, 0 .. single shot */
		/* urb->interval = urb->next ? 1 : 0; */
	}

	urb->status = -EINPROGRESS;
	urb->actual_length = 0;
	urb->error_count = 0;

	if (usb_pipecontrol (urb->pipe))
		hc_flush_data_cache (hci, urb->setup_packet, 8);
	if (usb_pipeout (urb->pipe))
		hc_flush_data_cache (hci, urb->transfer_buffer,
				     urb->transfer_buffer_length);

	qu_queue_urb (hci, urb);

	return 0;
}

/***************************************************************************
 * Function Name : hcs_return_urb
 *
 * This function the return path of URB back to the USB core. It calls the
 * the urb complete function if exist, and also handles the resubmition of
 * interrupt URBs.
 *
 * Input:  hci = data structure for the host controller
 *         urb = USB request block data structure 
 *         resub_ok = resubmit flag: 1 = submit urb again, 0 = not submit 
 *
 * Return: 0 
 **************************************************************************/
static int hcs_return_urb (hci_t * hci, struct urb * urb, int resub_ok)
{
	struct usb_device *dev = urb->dev;
	int resubmit = 0;

	DBGFUNC ("enter hcs_return_urb, urb pointer = 0x%x, "
		 "transferbuffer point = 0x%x, "
		 " setup packet pointer = 0x%x, context pointer = 0x%x \n",
		 (__u32 *) urb, (__u32 *) urb->transfer_buffer,
		 (__u32 *) urb->setup_packet, (__u32 *) urb->context);
	if (urb_debug)
		urb_print (urb, "RET", usb_pipeout (urb->pipe));

	resubmit = urb->interval && resub_ok;

	urb->dev = urb->hcpriv = NULL;

	if (urb->complete) {
		urb->complete (urb);	/* call complete */
	}

	if (resubmit) {
		/* requeue the URB */
		urb->dev = dev;
		hcs_urb_queue (hci, urb);
	} else {
		usb_put_urb(urb);
	}

	return 0;
}

/***************************************************************************
 * Function Name : hci_submit_urb
 *
 * This function is called by the USB core API when an URB is available to
 * process.  This function does the following
 *
 * 1) Check the validity of the URB
 * 2) Parse the device number from the URB
 * 3) Pass the URB to the root hub routine if its intended for the hub, else
 *    queue the urb for the attached device. 
 *
 * Input: urb = USB request block data structure 
 *
 * Return: 0 if success or error code 
 **************************************************************************/
static int hci_submit_urb (struct urb * urb, int mem_flags)
{
	hci_t *hci;
	unsigned int pipe = urb->pipe;
	unsigned long flags;
	int ret;

	DBGFUNC ("enter hci_submit_urb, pipe = 0x%x\n", urb->pipe);
	if (!urb->dev || !urb->dev->bus || urb->hcpriv)
		return -EINVAL;

	if (usb_endpoint_halted
	    (urb->dev, usb_pipeendpoint (pipe), usb_pipeout (pipe))) {
		printk ("hci_submit_urb: endpoint_halted\n");
		return -EPIPE;
	}
	hci = (hci_t *) urb->dev->bus->hcpriv;

	/* a request to the virtual root hub */
	if (usb_pipedevice (pipe) == hci->rh.devnum) {
		if (urb_debug > 1)
			urb_print (urb, "SUB-RH", usb_pipein (pipe));

		return rh_submit_urb (urb);
	}

	/* increment urb's reference count, we now control it. */
	urb = usb_get_urb (urb);

	/* queue the URB to its endpoint-queue */
	spin_lock_irqsave (&usb_urb_lock, flags);
	ret = hcs_urb_queue (hci, urb);
	if (ret != 0) {
		/* error on return */
		DBGERR ("hci_submit_urb: return err, ret = 0x%x, urb->status = 0x%x\n",
			ret, urb->status);
		usb_put_urb (urb);
	}

	spin_unlock_irqrestore (&usb_urb_lock, flags);

	return ret;

}

/***************************************************************************
 * Function Name : hci_unlink_urb
 *
 * This function mark the URB to unlink
 *
 * Input: urb = USB request block data structure 
 *
 * Return: 0 if success or error code 
 **************************************************************************/
static int hci_unlink_urb (struct urb * urb)
{
	unsigned long flags;
	hci_t *hci;
	DECLARE_WAITQUEUE (wait, current);
	void *comp = NULL;

	DBGFUNC ("enter hci_unlink_urb\n");

	if (!urb)		/* just to be sure */
		return -EINVAL;

	if (!urb->dev || !urb->dev->bus)
		return -ENODEV;

	hci = (hci_t *) urb->dev->bus->hcpriv;

	/* a request to the virtual root hub */
	if (usb_pipedevice (urb->pipe) == hci->rh.devnum) {
		return rh_unlink_urb (urb);
	}

	if (urb_debug)
		urb_print (urb, "UNLINK", 1);

	spin_lock_irqsave (&usb_urb_lock, flags);

	if (!list_empty (&urb->urb_list) && urb->status == -EINPROGRESS) {
		/* URB active? */

		if (urb->transfer_flags & (USB_ASYNC_UNLINK | USB_TIMEOUT_KILLED)) {
			/* asynchron with callback */

			list_del (&urb->urb_list);	/* relink the urb to the del list */
			list_add (&urb->urb_list, &hci->del_list);
			spin_unlock_irqrestore (&usb_urb_lock, flags);

		} else {
			/* synchron without callback */

			add_wait_queue (&hci->waitq, &wait);

			set_current_state (TASK_UNINTERRUPTIBLE);
			comp = urb->complete;
			urb->complete = NULL;

			list_del (&urb->urb_list);	/* relink the urb to the del list */
			list_add (&urb->urb_list, &hci->del_list);

			spin_unlock_irqrestore (&usb_urb_lock, flags);

			schedule_timeout (HZ / 50);

			if (!list_empty (&urb->urb_list))
				list_del (&urb->urb_list);

			urb->complete = comp;
			urb->hcpriv = NULL;
			remove_wait_queue (&hci->waitq, &wait);
		}
	} else {
		/* hcd does not own URB but we keep the driver happy anyway */
		spin_unlock_irqrestore (&usb_urb_lock, flags);

		if (urb->complete && (urb->transfer_flags & USB_ASYNC_UNLINK)) {
			urb->status = -ENOENT;
			urb->actual_length = 0;
			urb->complete (urb);
			urb->status = 0;
		} else {
			urb->status = -ENOENT;
		}
	}

	return 0;
}

/***************************************************************************
 * Function Name : hci_alloc_dev
 *
 * This function allocates private data space for the usb device and 
 * initialize the endpoint descriptor heads.
 *
 * Input: usb_dev = pointer to the usb device 
 *
 * Return: 0 if success or error code 
 **************************************************************************/
static int hci_alloc_dev (struct usb_device *usb_dev)
{
	struct hci_device *dev;
	int i;

	DBGFUNC ("enter hci_alloc_dev\n");
	dev = kmalloc (sizeof (*dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	memset (dev, 0, sizeof (*dev));

	for (i = 0; i < 32; i++) {
		INIT_LIST_HEAD (&(dev->ed[i].urb_queue));
		dev->ed[i].pipe_head = NULL;
	}

	usb_dev->hcpriv = dev;

	DBGVERBOSE ("USB HC dev alloc %d bytes\n", sizeof (*dev));

	return 0;

}

/***************************************************************************
 * Function Name : hci_free_dev
 *
 * This function de-allocates private data space for the usb devic
 *
 * Input: usb_dev = pointer to the usb device 
 *
 * Return: 0  
 **************************************************************************/
static int hci_free_dev (struct usb_device *usb_dev)
{
	DBGFUNC ("enter hci_free_dev\n");

	if (usb_dev->hcpriv)
		kfree (usb_dev->hcpriv);

	usb_dev->hcpriv = NULL;

	return 0;
}

/***************************************************************************
 * Function Name : hci_get_current_frame_number
 *
 * This function get the current USB frame number
 *
 * Input: usb_dev = pointer to the usb device 
 *
 * Return: frame number  
 **************************************************************************/
static int hci_get_current_frame_number (struct usb_device *usb_dev)
{
	hci_t *hci = usb_dev->bus->hcpriv;
	DBGFUNC ("enter hci_get_current_frame_number, frame = 0x%x \r\n",
		 hci->frame_number);

	return (hci->frame_number);
}

/***************************************************************************
 * List of all io-functions 
 **************************************************************************/

static struct usb_operations hci_device_operations = {
	allocate:		hci_alloc_dev,
	deallocate:		hci_free_dev,
	get_frame_number:	hci_get_current_frame_number,
	submit_urb:		hci_submit_urb,
	unlink_urb:		hci_unlink_urb,
};

/***************************************************************************
 * URB queueing:
 * 
 * For each type of transfer (INTR, BULK, ISO, CTRL) there is a list of 
 * active URBs.