Commit 6f65126c authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: OHCI: add SG support 



Apparently nobody ever remembered to add Scatter-Gather support to
ohci-hcd.  This patch adds it.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1299cff9

drivers/usb/host/ohci-hcd.c

+32 −6
Original line number Diff line number Diff line
@@ -109,6 +109,33 @@ MODULE_PARM_DESC (no_handshake, "true (not default) disables BIOS handshake"); 


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



static int number_of_tds(struct urb *urb)

{

	int			len, i, num, this_sg_len;

	struct scatterlist	*sg;



	len = urb->transfer_buffer_length;

	i = urb->num_mapped_sgs;



	if (len > 0 && i > 0) {		/* Scatter-gather transfer */

		num = 0;

		sg = urb->sg;

		for (;;) {

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

			num += DIV_ROUND_UP(this_sg_len, 4096);

			len -= this_sg_len;

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

				break;

			sg = sg_next(sg);

		}



	} else {			/* Non-SG transfer */

		/* one TD for every 4096 Bytes (could be up to 8K) */

		num = DIV_ROUND_UP(len, 4096);

	}

	return num;

}



/*

 * queue up an urb for anything except the root hub

 */
@@ -142,12 +169,8 @@ static int ohci_urb_enqueue ( 
		// case PIPE_INTERRUPT:

		// case PIPE_BULK:

		default:

			/* one TD for every 4096 Bytes (can be up to 8K) */

			size += urb->transfer_buffer_length / 4096;

			/* ... and for any remaining bytes ... */

			if ((urb->transfer_buffer_length % 4096) != 0)

				size++;

			/* ... and maybe a zero length packet to wrap it up */

			size += number_of_tds(urb);

			/* maybe a zero-length packet to wrap it up */

			if (size == 0)

				size++;

			else if ((urb->transfer_flags & URB_ZERO_PACKET) != 0
@@ -506,6 +529,9 @@ static int ohci_init (struct ohci_hcd *ohci) 
	int ret;

	struct usb_hcd *hcd = ohci_to_hcd(ohci);



	/* Accept arbitrarily long scatter-gather lists */

	hcd->self.sg_tablesize = ~0;



	if (distrust_firmware)

		ohci->flags |= OHCI_QUIRK_HUB_POWER;

drivers/usb/host/ohci-q.c

+41 −13
Original line number Diff line number Diff line
@@ -602,6 +602,8 @@ static void td_submit_urb ( 
	u32		info = 0;

	int		is_out = usb_pipeout (urb->pipe);

	int		periodic = 0;

	int		i, this_sg_len, n;

	struct scatterlist	*sg;



	/* OHCI handles the bulk/interrupt data toggles itself.  We just

	 * use the device toggle bits for resetting, and rely on the fact
@@ -615,10 +617,24 @@ static void td_submit_urb ( 


	list_add (&urb_priv->pending, &ohci->pending);



	i = urb->num_mapped_sgs;

	if (data_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), data_len);

	} else {

		sg = NULL;

		if (data_len)

			data = urb->transfer_dma;

		else

			data = 0;

		this_sg_len = data_len;

	}



	/* NOTE:  TD_CC is set so we can tell which TDs the HC processed by

	 * using TD_CC_GET, as well as by seeing them on the done list.
@@ -639,17 +655,29 @@ static void td_submit_urb ( 
			? TD_T_TOGGLE | TD_CC | TD_DP_OUT

			: TD_T_TOGGLE | TD_CC | TD_DP_IN;

		/* TDs _could_ transfer up to 8K each */

		while (data_len > 4096) {

			td_fill (ohci, info, data, 4096, urb, cnt);

			data += 4096;

			data_len -= 4096;

			cnt++;

		}

		for (;;) {

			n = min(this_sg_len, 4096);



			/* maybe avoid ED halt on final TD short read */

			if (n >= data_len || (i == 1 && n >= this_sg_len)) {

				if (!(urb->transfer_flags & URB_SHORT_NOT_OK))

					info |= TD_R;

		td_fill (ohci, info, data, data_len, urb, cnt);

			}

			td_fill(ohci, info, data, n, urb, cnt);

			this_sg_len -= n;

			data_len -= n;

			data += n;

			cnt++;



			if (this_sg_len <= 0) {

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

					break;

				sg = sg_next(sg);

				data = sg_dma_address(sg);

				this_sg_len = min_t(int, sg_dma_len(sg),

						data_len);

			}

		}

		if ((urb->transfer_flags & URB_ZERO_PACKET)

				&& cnt < urb_priv->length) {

			td_fill (ohci, info, 0, 0, urb, cnt);