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USB: OHCI: add SG support

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

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern
2014-07-17 16:30:01 -04:00
committed by Greg Kroah-Hartman
parent 1299cff9fa
commit 6f65126c76
2 changed files with 73 additions and 19 deletions
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54
drivers/usb/host/ohci-q.c
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@@ -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);
if (data_len)
data = urb->transfer_dma;
else
data = 0;
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;
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, 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);
}
}
/* maybe avoid ED halt on final TD short read */
if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
info |= TD_R;
td_fill (ohci, info, data, data_len, urb, cnt);
cnt++;
if ((urb->transfer_flags & URB_ZERO_PACKET)
&& cnt < urb_priv->length) {
td_fill (ohci, info, 0, 0, urb, cnt);