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USB: EHCI: add native scatter-gather support 

This patch (as1300) adds native scatter-gather support to ehci-hcd.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2009-11-06 12:29:40 -05:00 committed by Greg Kroah-Hartman
parent 3a2b808e95
commit 40f8db8f8f
2 changed files with 29 additions and 5 deletions
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2
drivers/usb/host/ehci-hcd.c
View File

@ -605,6 +605,8 @@ static int ehci_init(struct usb_hcd *hcd)
}
ehci->command = temp;
/* Accept arbitrarily long scatter-gather lists */
hcd->self.sg_tablesize = ~0;
return 0;
}

32
drivers/usb/host/ehci-q.c
View File

@ -616,9 +616,11 @@ qh_urb_transaction (
) {
struct ehci_qtd *qtd, *qtd_prev;
dma_addr_t buf;
int len, maxpacket;
int len, this_sg_len, maxpacket;
int is_input;
u32 token;
int i;
struct scatterlist *sg;
/*
* URBs map to sequences of QTDs: one logical transaction
@ -659,7 +661,20 @@ qh_urb_transaction (
/*
* data transfer stage: buffer setup
*/
buf = urb->transfer_dma;
i = urb->num_sgs;
if (len > 0 && i > 0) {
sg = urb->sg->sg;
buf = 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;
buf = urb->transfer_dma;
this_sg_len = len;
}
if (is_input)
token |= (1 /* "in" */ << 8);
@ -675,7 +690,9 @@ qh_urb_transaction (
for (;;) {
int this_qtd_len;
this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token,
maxpacket);
this_sg_len -= this_qtd_len;
len -= this_qtd_len;
buf += this_qtd_len;
@ -691,8 +708,13 @@ qh_urb_transaction (
if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
token ^= QTD_TOGGLE;
if (likely (len <= 0))
break;
if (likely(this_sg_len <= 0)) {
if (--i <= 0 || len <= 0)
break;
sg = sg_next(sg);
buf = sg_dma_address(sg);
this_sg_len = min_t(int, sg_dma_len(sg), len);
}
qtd_prev = qtd;
qtd = ehci_qtd_alloc (ehci, flags);