USB: OHCI: add SG support

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>

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 6f8ec52c7e0c95646e7dd9da81f14d3013fce50f..7f94c586c5dcb64f2c3a8c50fda6f3dbbc4b9b9f 100644 (file)
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -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;
 

diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c
index d4253e319428ed449e877b1c246101d99e3675ce..517d04d5c150a694511b15f7e8e93db3ba09e505 100644 (file)
--- a/drivers/usb/host/ohci-q.c
+++ b/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);