USB: xHCI: Introduce urb_priv structure

Add urb_priv data structure to xHCI driver. This structure allows multiple
xhci TDs to be linked to one urb, which is essential for isochronous
transfer. For non-isochronous urb, only one TD is needed for one urb;
for isochronous urb, the TD number for the urb is equal to
urb->number_of_packets.

The length field of urb_priv indicates the number of TDs in the urb.
The td_cnt field indicates the number of TDs already processed by xHC.
When td_cnt matches length, the urb can be given back to usbcore.

When an urb is dequeued or cancelled, add all the unprocessed TDs to the
endpoint's cancelled_td_list. When process a cancelled TD, increase
td_cnt field. When td_cnt equals urb_priv->length, giveback the
cancelled urb.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 64d036804715..44eeaa016f1b 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1390,6 +1390,22 @@ struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
         return command;
 }
 
+void xhci_urb_free_priv(struct xhci_hcd *xhci, struct urb_priv *urb_priv)
+{
+        int last;
+
+        if (!urb_priv)
+                return;
+
+        last = urb_priv->length - 1;
+        if (last >= 0) {
+                int     i;
+                for (i = 0; i <= last; i++)
+                        kfree(urb_priv->td[i]);
+        }
+        kfree(urb_priv);
+}
+
 void xhci_free_command(struct xhci_hcd *xhci,
                 struct xhci_command *command)
 {