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Commit 689d6eac authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
Browse files

USB: UHCI: add native scatter-gather support(v1) 



This patch adds native scatter-gather support to uhci-hcd.

Reviewed-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 00be545e

drivers/usb/host/uhci-q.c

+29 −4
Original line number Diff line number Diff line
@@ -917,10 +917,13 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb, 
	unsigned long destination, status;

	int maxsze = le16_to_cpu(qh->hep->desc.wMaxPacketSize);

	int len = urb->transfer_buffer_length;

	dma_addr_t data = urb->transfer_dma;

	int this_sg_len;

	dma_addr_t data;

	__le32 *plink;

	struct urb_priv *urbp = urb->hcpriv;

	unsigned int toggle;

	struct scatterlist  *sg;

	int i;



	if (len < 0)

		return -EINVAL;
@@ -937,12 +940,26 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb, 
	if (usb_pipein(urb->pipe))

		status |= TD_CTRL_SPD;



	i = urb->num_sgs;

	if (len > 0 && i > 0) {

		sg = urb->sg;

		data = sg_dma_address(sg);



		/* urb->transfer_buffer_length may be smaller than the

		 * size of the scatterlist (or vice versa)

		 */

		this_sg_len = min_t(int, sg_dma_len(sg), len);

	} else {

		sg = NULL;

		data = urb->transfer_dma;

		this_sg_len = len;

	}

	/*

	 * Build the DATA TDs

	 */

	plink = NULL;

	td = qh->dummy_td;

	do {	/* Allow zero length packets */

	for (;;) {	/* Allow zero length packets */

		int pktsze = maxsze;



		if (len <= pktsze) {		/* The last packet */
@@ -965,10 +982,18 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb, 
		plink = &td->link;

		status |= TD_CTRL_ACTIVE;



		toggle ^= 1;

		data += pktsze;

		this_sg_len -= pktsze;

		len -= maxsze;

		toggle ^= 1;

	} while (len > 0);

		if (this_sg_len <= 0) {

			if (--i <= 0 || len <= 0)

				break;

			sg = sg_next(sg);

			data = sg_dma_address(sg);

			this_sg_len = min_t(int, sg_dma_len(sg), len);

		}

	}



	/*

	 * URB_ZERO_PACKET means adding a 0-length packet, if direction