path: root/drivers/usb/core/message.c

/*
 * message.c - synchronous message handling
 */

#include <linux/pci.h>	/* for scatterlist macros */
#include <linux/usb.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <asm/byteorder.h>
#include <asm/scatterlist.h>

#include "hcd.h"	/* for usbcore internals */
#include "usb.h"

static void usb_api_blocking_completion(struct urb *urb, struct pt_regs *regs)
{
	complete((struct completion *)urb->context);
}


static void timeout_kill(unsigned long data)
{
	struct urb	*urb = (struct urb *) data;

	usb_unlink_urb(urb);
}

// Starts urb and waits for completion or timeout
// note that this call is NOT interruptible, while
// many device driver i/o requests should be interruptible
static int usb_start_wait_urb(struct urb *urb, int timeout, int* actual_length)
{ 
	struct completion	done;
	struct timer_list	timer;
	int			status;

	init_completion(&done); 	
	urb->context = &done;
	urb->actual_length = 0;
	status = usb_submit_urb(urb, GFP_NOIO);

	if (status == 0) {
		if (timeout > 0) {
			init_timer(&timer);
			timer.expires = jiffies + msecs_to_jiffies(timeout);
			timer.data = (unsigned long)urb;
			timer.function = timeout_kill;
			/* grr.  timeout _should_ include submit delays. */
			add_timer(&timer);
		}
		wait_for_completion(&done);
		status = urb->status;
		/* note:  HCDs return ETIMEDOUT for other reasons too */
		if (status == -ECONNRESET) {
			dev_dbg(&urb->dev->dev,
				"%s timed out on ep%d%s len=%d/%d\n",
				current->comm,
				usb_pipeendpoint(urb->pipe),
				usb_pipein(urb->pipe) ? "in" : "out",
				urb->actual_length,
				urb->transfer_buffer_length
				);
			if (urb->actual_length > 0)
				status = 0;
			else
				status = -ETIMEDOUT;
		}
		if (timeout > 0)
			del_timer_sync(&timer);
	}

	if (actual_length)
		*actual_length = urb->actual_length;
	usb_free_urb(urb);
	return status;
}

/*-------------------------------------------------------------------*/
// returns status (negative) or length (positive)
static int usb_internal_control_msg(struct usb_device *usb_dev,
				    unsigned int pipe, 
				    struct usb_ctrlrequest *cmd,
				    void *data, int len, int timeout)
{
	struct urb *urb;
	int retv;
	int length;

	urb = usb_alloc_urb(0, GFP_NOIO);
	if (!urb)
		return -ENOMEM;
  
	usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
			     len, usb_api_blocking_completion, NULL);

	retv = usb_start_wait_urb(urb, timeout, &length);
	if (retv < 0)
		return retv;
	else
		return length;
}

/**
 *	usb_control_msg - Builds a control urb, sends it off and waits for completion
 *	@dev: pointer to the usb device to send the message to
 *	@pipe: endpoint "pipe" to send the message to
 *	@request: USB message request value
 *	@requesttype: USB message request type value
 *	@value: USB message value
 *	@index: USB message index value
 *	@data: pointer to the data to send
 *	@size: length in bytes of the data to send
 *	@timeout: time in msecs to wait for the message to complete before
 *		timing out (if 0 the wait is forever)
 *	Context: !in_interrupt ()
 *
 *	This function sends a simple control message to a specified endpoint
 *	and waits for the message to complete, or timeout.
 *	
 *	If successful, it returns the number of bytes transferred, otherwise a negative error number.
 *
 *	Don't use this function from within an interrupt context, like a
 *	bottom half handler.  If you need an asynchronous message, or need to send
 *	a message from within interrupt context, use usb_submit_urb()
 *      If a thread in your driver uses this call, make sure your disconnect()
 *      method can wait for it to complete.  Since you don't have a handle on
 *      the URB used, you can't cancel the request.
 */
int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request, __u8 requesttype,
			 __u16 value, __u16 index, void *data, __u16 size, int timeout)
{
	struct usb_ctrlrequest *dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
	int ret;
	
	if (!dr)
		return -ENOMEM;

	dr->bRequestType= requesttype;
	dr->bRequest = request;
	dr->wValue = cpu_to_le16p(&value);
	dr->wIndex = cpu_to_le16p(&index);
	dr->wLength = cpu_to_le16p(&size);

	//dbg("usb_control_msg");	

	ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);

	kfree(dr);

	return ret;
}


/**
 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
 * @usb_dev: pointer to the usb device to send the message to
 * @pipe: endpoint "pipe" to send the message to
 * @data: pointer to the data to send
 * @len: length in bytes of the data to send
 * @actual_length: pointer to a location to put the actual length transferred in bytes
 * @timeout: time in msecs to wait for the message to complete before
 *	timing out (if 0 the wait is forever)
 * Context: !in_interrupt ()
 *
 * This function sends a simple interrupt message to a specified endpoint and
 * waits for the message to complete, or timeout.
 *
 * If successful, it returns 0, otherwise a negative error number.  The number
 * of actual bytes transferred will be stored in the actual_length paramater.
 *
 * Don't use this function from within an interrupt context, like a bottom half
 * handler.  If you need an asynchronous message, or need to send a message
 * from within interrupt context, use usb_submit_urb() If a thread in your
 * driver uses this call, make sure your disconnect() method can wait for it to
 * complete.  Since you don't have a handle on the URB used, you can't cancel
 * the request.
 */
int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
		      void *data, int len, int *actual_length, int timeout)
{
	return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
}
EXPORT_SYMBOL_GPL(usb_interrupt_msg);

/**
 *	usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
 *	@usb_dev: pointer to the usb device to send the message to
 *	@pipe: endpoint "pipe" to send the message to
 *	@data: pointer to the data to send
 *	@len: length in bytes of the data to send
 *	@actual_length: pointer to a location to put the actual length transferred in bytes
 *	@timeout: time in msecs to wait for the message to complete before
 *		timing out (if 0 the wait is forever)
 *	Context: !in_interrupt ()
 *
 *	This function sends a simple bulk message to a specified endpoint
 *	and waits for the message to complete, or timeout.
 *	
 *	If successful, it returns 0, otherwise a negative error number.
 *	The number of actual bytes transferred will be stored in the 
 *	actual_length paramater.
 *
 *	Don't use this function from within an interrupt context, like a
 *	bottom half handler.  If you need an asynchronous message, or need to
 *	send a message from within interrupt context, use usb_submit_urb()
 *      If a thread in your driver uses this call, make sure your disconnect()
 *      method can wait for it to complete.  Since you don't have a handle on
 *      the URB used, you can't cancel the request.
 *
 *	Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT
 *	ioctl, users are forced to abuse this routine by using