message.c

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/*
 * 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 <linux/scatterlist.h>
#include <linux/usb/quirks.h>
#include <asm/byteorder.h>

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

struct api_context {
	struct completion	done;
	int			status;
};

static void usb_api_blocking_completion(struct urb *urb)
{
	struct api_context *ctx = urb->context;

	ctx->status = urb->status;
	complete(&ctx->done);
}


/*
 * Starts urb and waits for completion or timeout. Note that this call
 * is NOT interruptible. Many device driver i/o requests should be
 * interruptible and therefore these drivers should implement their
 * own interruptible routines.
 */
static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
{ 
	struct api_context ctx;
	unsigned long expire;
	int retval;

	init_completion(&ctx.done);
	urb->context = &ctx;
	urb->actual_length = 0;
	retval = usb_submit_urb(urb, GFP_NOIO);
	if (unlikely(retval))
		goto out;

	expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
	if (!wait_for_completion_timeout(&ctx.done, expire)) {
		usb_kill_urb(urb);
		retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);

		dev_dbg(&urb->dev->dev,
			"%s timed out on ep%d%s len=%d/%d\n",
			current->comm,
			usb_endpoint_num(&urb->ep->desc),
			usb_urb_dir_in(urb) ? "in" : "out",
			urb->actual_length,
			urb->transfer_buffer_length);
	} else
		retval = ctx.status;
out:
	if (actual_length)
		*actual_length = urb->actual_length;

	usb_free_urb(urb);
	return retval;
}

/*-------------------------------------------------------------------*/
// 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 it to submit
 *	URBs for interrupt endpoints.  We will take the liberty of creating
 *	an interrupt URB (with the default interval) if the target is an
 *	interrupt endpoint.
 */
int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, 
			void *data, int len, int *actual_length, int timeout)
{
	struct urb *urb;
	struct usb_host_endpoint *ep;

	ep = (usb_pipein(pipe) ? usb_dev->ep_in : usb_dev->ep_out)
			[usb_pipeendpoint(pipe)];
	if (!ep || len < 0)
		return -EINVAL;

	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!urb)
		return -ENOMEM;

	if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
			USB_ENDPOINT_XFER_INT) {
		pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
		usb_fill_int_urb(urb, usb_dev, pipe, data, len,
				usb_api_blocking_completion, NULL,
				ep->desc.bInterval);
	} else
		usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
				usb_api_blocking_completion, NULL);

	return usb_start_wait_urb(urb, timeout, actual_length);
}

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

static void sg_clean (struct usb_sg_request *io)
{
	if (io->urbs) {
		while (io->entries--)
			usb_free_urb (io->urbs [io->entries]);
		kfree (io->urbs);
		io->urbs = NULL;
	}
	if (io->dev->dev.dma_mask != NULL)
		usb_buffer_unmap_sg (io->dev, usb_pipein(io->pipe),
				io->sg, io->nents);
	io->dev = NULL;
}

static void sg_complete (struct urb *urb)
{
	struct usb_sg_request	*io = urb->context;
	int status = urb->status;

	spin_lock (&io->lock);

	/* In 2.5 we require hcds' endpoint queues not to progress after fault
	 * reports, until the completion callback (this!) returns.  That lets
	 * device driver code (like this routine) unlink queued urbs first,
	 * if it needs to, since the HC won't work on them at all.  So it's
	 * not possible for page N+1 to overwrite page N, and so on.
	 *
	 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
	 * complete before the HCD can get requests away from hardware,
	 * though never during cleanup after a hard fault.
	 */
	if (io->status
			&& (io->status != -ECONNRESET
				|| status != -ECONNRESET)
			&& urb->actual_length) {
		dev_err (io->dev->bus->controller,
			"dev %s ep%d%s scatterlist error %d/%d\n",
			io->dev->devpath,
			usb_endpoint_num(&urb->ep->desc),
			usb_urb_dir_in(urb) ? "in" : "out",
			status, io->status);
		// BUG ();
	}

	if (io->status == 0 && status && status != -ECONNRESET) {
		int i, found, retval;

		io->status = status;

		/* the previous urbs, and this one, completed already.
		 * unlink pending urbs so they won't rx/tx bad data.
		 * careful: unlink can sometimes be synchronous...
		 */
		spin_unlock (&io->lock);
		for (i = 0, found = 0; i < io->entries; i++) {
			if (!io->urbs [i] || !io->urbs [i]->dev)
				continue;
			if (found) {
				retval = usb_unlink_urb (io->urbs [i]);
				if (retval != -EINPROGRESS &&
				    retval != -ENODEV &&
				    retval != -EBUSY)
					dev_err (&io->dev->dev,
						"%s, unlink --> %d\n",
						__FUNCTION__, retval);
			} else if (urb == io->urbs [i])
				found = 1;
		}
		spin_lock (&io->lock);
	}
	urb->dev = NULL;

	/* on the last completion, signal usb_sg_wait() */
	io->bytes += urb->actual_length;
	io->count--;
	if (!io->count)
		complete (&io->complete);

	spin_unlock (&io->lock);
}


/**
 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
 * @io: request block being initialized.  until usb_sg_wait() returns,
 *	treat this as a pointer to an opaque block of memory,
 * @dev: the usb device that will send or receive the data
 * @pipe: endpoint "pipe" used to transfer the data
 * @period: polling rate for interrupt endpoints, in frames or
 * 	(for high speed endpoints) microframes; ignored for bulk
 * @sg: scatterlist entries
 * @nents: how many entries in the scatterlist
 * @length: how many bytes to send from the scatterlist, or zero to
 * 	send every byte identified in the list.
 * @mem_flags: SLAB_* flags affecting memory allocations in this call
 *
 * Returns zero for success, else a negative errno value.  This initializes a
 * scatter/gather request, allocating resources such as I/O mappings and urb
 * memory (except maybe memory used by USB controller drivers).
 *
 * The request must be issued using usb_sg_wait(), which waits for the I/O to
 * complete (or to be canceled) and then cleans up all resources allocated by
 * usb_sg_init().
 *
 * The request may be canceled with usb_sg_cancel(), either before or after
 * usb_sg_wait() is called.
 */
int usb_sg_init (
	struct usb_sg_request	*io,
	struct usb_device	*dev,
	unsigned		pipe, 
	unsigned		period,
	struct scatterlist	*sg,
	int			nents,
	size_t			length,
	gfp_t			mem_flags
)
{
	int			i;
	int			urb_flags;
	int			dma;

	if (!io || !dev || !sg
			|| usb_pipecontrol (pipe)
			|| usb_pipeisoc (pipe)
			|| nents <= 0)
		return -EINVAL;

	spin_lock_init (&io->lock);
	io->dev = dev;
	io->pipe = pipe;
	io->sg = sg;
	io->nents = nents;

	/* not all host controllers use DMA (like the mainstream pci ones);
	 * they can use PIO (sl811) or be software over another transport.
	 */
	dma = (dev->dev.dma_mask != NULL);
	if (dma)
		io->entries = usb_buffer_map_sg(dev, usb_pipein(pipe),
				sg, nents);
	else
		io->entries = nents;

	/* initialize all the urbs we'll use */
	if (io->entries <= 0)
		return io->entries;

	io->count = io->entries;
	io->urbs = kmalloc (io->entries * sizeof *io->urbs, mem_flags);
	if (!io->urbs)
		goto nomem;

	urb_flags = URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT;
	if (usb_pipein (pipe))
		urb_flags |= URB_SHORT_NOT_OK;

	for (i = 0; i < io->entries; i++) {
		unsigned		len;

		io->urbs [i] = usb_alloc_urb (0, mem_flags);
		if (!io->urbs [i]) {
			io->entries = i;
			goto nomem;
		}

		io->urbs [i]->dev = NULL;
		io->urbs [i]->pipe = pipe;
		io->urbs [i]->interval = period;
		io->urbs [i]->transfer_flags = urb_flags;

		io->urbs [i]->complete = sg_complete;
		io->urbs [i]->context = io;

		/*
		 * Some systems need to revert to PIO when DMA is temporarily
		 * unavailable.  For their sakes, both transfer_buffer and
		 * transfer_dma are set when possible.  However this can only
		 * work on systems without:
		 *
		 *  - HIGHMEM, since DMA buffers located in high memory are
		 *    not directly addressable by the CPU for PIO;