USB: xhci: Support interrupt transfers.

Interrupt transfers are submitted to the xHCI hardware using the same TRB
type as bulk transfers.  Re-use the bulk transfer enqueueing code to
enqueue interrupt transfers.

Interrupt transfers are a bit different than bulk transfers.  When the
interrupt endpoint is to be serviced, the xHC will consume (at most) one
TD.  A TD (comprised of sg list entries) can take several service
intervals to transmit.  The important thing for device drivers to note is
that if they use the scatter gather interface to submit interrupt
requests, they will not get data sent from two different scatter gather
lists in the same service interval.

For now, the xHCI driver will use the service interval from the endpoint's
descriptor (bInterval).  Drivers will need a hook to poll at a more
frequent interval.  Set urb->interval to the interval that the xHCI
hardware will use.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 1d4a1e3f953354deefa1c28ece7f3a311401455d..e478a63488fbd7c355a12dff6924bc2f4cbf6d6e 100644 (file)
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -727,6 +727,11 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
                ret = xhci_queue_bulk_tx(xhci, GFP_ATOMIC, urb,
                                slot_id, ep_index);
                spin_unlock_irqrestore(&xhci->lock, flags);
+       } else if (usb_endpoint_xfer_int(&urb->ep->desc)) {
+               spin_lock_irqsave(&xhci->lock, flags);
+               ret = xhci_queue_intr_tx(xhci, GFP_ATOMIC, urb,
+                               slot_id, ep_index);
+               spin_unlock_irqrestore(&xhci->lock, flags);
        } else {
                ret = -EINVAL;
        }

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index aac379e1c88373a6f37af30798e431f1502d127c..ff5e6bc2299d560d2a1340151015a5e910c7b955 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1072,7 +1072,12 @@ static int handle_tx_event(struct xhci_hcd *xhci,
                                else
                                        status = 0;
                        } else {
-                               xhci_dbg(xhci, "Successful bulk transfer!\n");
+                               if (usb_endpoint_xfer_bulk(&td->urb->ep->desc))
+                                       xhci_dbg(xhci, "Successful bulk "
+                                                       "transfer!\n");
+                               else
+                                       xhci_dbg(xhci, "Successful interrupt "
+                                                       "transfer!\n");
                                status = 0;
                        }
                        break;
@@ -1464,6 +1469,47 @@ static void giveback_first_trb(struct xhci_hcd *xhci, int slot_id,
        ring_ep_doorbell(xhci, slot_id, ep_index);
 }
 
+/*
+ * xHCI uses normal TRBs for both bulk and interrupt.  When the interrupt
+ * endpoint is to be serviced, the xHC will consume (at most) one TD.  A TD
+ * (comprised of sg list entries) can take several service intervals to
+ * transmit.
+ */
+int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+               struct urb *urb, int slot_id, unsigned int ep_index)
+{
+       struct xhci_ep_ctx *ep_ctx = xhci_get_ep_ctx(xhci,
+                       xhci->devs[slot_id]->out_ctx, ep_index);
+       int xhci_interval;
+       int ep_interval;
+
+       xhci_interval = EP_INTERVAL_TO_UFRAMES(ep_ctx->ep_info);
+       ep_interval = urb->interval;
+       /* Convert to microframes */
+       if (urb->dev->speed == USB_SPEED_LOW ||
+                       urb->dev->speed == USB_SPEED_FULL)
+               ep_interval *= 8;
+       /* FIXME change this to a warning and a suggestion to use the new API
+        * to set the polling interval (once the API is added).
+        */
+       if (xhci_interval != ep_interval) {
+               if (!printk_ratelimit())
+                       dev_dbg(&urb->dev->dev, "Driver uses different interval"
+                                       " (%d microframe%s) than xHCI "
+                                       "(%d microframe%s)\n",
+                                       ep_interval,
+                                       ep_interval == 1 ? "" : "s",
+                                       xhci_interval,
+                                       xhci_interval == 1 ? "" : "s");
+               urb->interval = xhci_interval;
+               /* Convert back to frames for LS/FS devices */
+               if (urb->dev->speed == USB_SPEED_LOW ||
+                               urb->dev->speed == USB_SPEED_FULL)
+                       urb->interval /= 8;
+       }
+       return xhci_queue_bulk_tx(xhci, GFP_ATOMIC, urb, slot_id, ep_index);
+}
+
 static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                struct urb *urb, int slot_id, unsigned int ep_index)
 {

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index bc64b500feb8b7f02a9deb58e6df9731bf2d123f..a7728aa91582ed700fb7620c56f6d6cca641d69a 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -581,6 +581,7 @@ struct xhci_ep_ctx {
 /* bit 15 is Linear Stream Array */
 /* Interval - period between requests to an endpoint - 125u increments. */
 #define EP_INTERVAL(p)         ((p & 0xff) << 16)
+#define EP_INTERVAL_TO_UFRAMES(p)              (1 << (((p) >> 16) & 0xff))
 
 /* ep_info2 bitmasks */
 /*
@@ -1223,6 +1224,8 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb,
                int slot_id, unsigned int ep_index);
 int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb,
                int slot_id, unsigned int ep_index);
+int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb,
+               int slot_id, unsigned int ep_index);
 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
                u32 slot_id);
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,