Apparently nobody ever remembered to add Scatter-Gather support to
ohci-hcd. This patch adds it.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
[as1760]
drivers/usb/host/ohci-hcd.c | 38 ++++++++++++++++++++++++++----
drivers/usb/host/ohci-q.c | 54 +++++++++++++++++++++++++++++++++-----------
2 files changed, 73 insertions(+), 19 deletions(-)
Index: usb-3.16/drivers/usb/host/ohci-hcd.c
===================================================================
--- usb-3.16.orig/drivers/usb/host/ohci-hcd.c
+++ usb-3.16/drivers/usb/host/ohci-hcd.c
@@ -109,6 +109,33 @@ MODULE_PARM_DESC (no_handshake, "true (n
/*-------------------------------------------------------------------------*/
+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 *o
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;
Index: usb-3.16/drivers/usb/host/ohci-q.c
===================================================================
--- usb-3.16.orig/drivers/usb/host/ohci-q.c
+++ usb-3.16/drivers/usb/host/ohci-q.c
@@ -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);
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
