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

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

Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Ming Lei 2010-09-30 20:32:44 +08:00 committed by Greg Kroah-Hartman
parent 00be545e49
commit 689d6eacd1
1 changed files with 30 additions and 5 deletions
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35
drivers/usb/host/uhci-q.c
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@ -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;
data += pktsze;
len -= maxsze;
toggle ^= 1;
} while (len > 0);
data += pktsze;
this_sg_len -= pktsze;
len -= maxsze;
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