svn commit: r261795 - head/sys/dev/usb/controller

[Hans Petter Selasky]

Author: hselasky
Date: Wed Feb 12 08:04:38 2014
New Revision: 261795
URL: http://svnweb.freebsd.org/changeset/base/261795

Log:
  Issue doorbell twice before finally freeing the DMA descriptors. This
  should fix DMA descriptor caching issues seen with the EHCI controller
  found in Google Chromebook C720 during removal and insertion of USB
  devices.
  
  MFC after:	1 week
  Reported by:	Matthew Dillon at DragonFlyBSD

Modified:
  head/sys/dev/usb/controller/ehci.c

Modified: head/sys/dev/usb/controller/ehci.c
==============================================================================
--- head/sys/dev/usb/controller/ehci.c	Wed Feb 12 07:51:14 2014	(r261794)
+++ head/sys/dev/usb/controller/ehci.c	Wed Feb 12 08:04:38 2014	(r261795)
@@ -2261,10 +2261,26 @@ ehci_device_bulk_enter(struct usb_xfer *
 }
 
 static void
+ehci_doorbell_async(struct ehci_softc *sc)
+{
+	uint32_t temp;
+
+	/*
+	 * XXX Performance quirk: Some Host Controllers have a too low
+	 * interrupt rate. Issue an IAAD to stimulate the Host
+	 * Controller after queueing the BULK transfer.
+	 *
+	 * XXX Force the host controller to refresh any QH caches.
+	 */
+	temp = EOREAD4(sc, EHCI_USBCMD);
+	if (!(temp & EHCI_CMD_IAAD))
+		EOWRITE4(sc, EHCI_USBCMD, temp | EHCI_CMD_IAAD);
+}
+
+static void
 ehci_device_bulk_start(struct usb_xfer *xfer)
 {
 	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
-	uint32_t temp;
 
 	/* setup TD's and QH */
 	ehci_setup_standard_chain(xfer, &sc->sc_async_p_last);
@@ -2279,13 +2295,7 @@ ehci_device_bulk_start(struct usb_xfer *
 	if (sc->sc_flags & EHCI_SCFLG_IAADBUG)
 		return;
 
-	/* XXX Performance quirk: Some Host Controllers have a too low
-	 * interrupt rate. Issue an IAAD to stimulate the Host
-	 * Controller after queueing the BULK transfer.
-	 */
-	temp = EOREAD4(sc, EHCI_USBCMD);
-	if (!(temp & EHCI_CMD_IAAD))
-		EOWRITE4(sc, EHCI_USBCMD, temp | EHCI_CMD_IAAD);
+	ehci_doorbell_async(sc);
 }
 
 static const struct usb_pipe_methods ehci_device_bulk_methods =
@@ -3902,6 +3912,41 @@ ehci_set_hw_power(struct usb_bus *bus)
 	return;
 }
 
+static void
+ehci_start_dma_delay_second(struct usb_xfer *xfer)
+{
+	struct ehci_softc *sc = EHCI_BUS2SC(xfer->xroot->bus);
+
+	DPRINTF("\n");
+
+	/* trigger doorbell */
+	ehci_doorbell_async(sc);
+
+	/* give the doorbell 4ms */
+	usbd_transfer_timeout_ms(xfer,
+	    (void (*)(void *))&usb_dma_delay_done_cb, 4);
+}
+
+/*
+ * Ring the doorbell twice before freeing any DMA descriptors. Some host
+ * controllers apparently cache the QH descriptors and need a message
+ * that the cache needs to be discarded.
+ */
+static void
+ehci_start_dma_delay(struct usb_xfer *xfer)
+{
+	struct ehci_softc *sc = EHCI_BUS2SC(xfer->xroot->bus);
+
+	DPRINTF("\n");
+
+	/* trigger doorbell */
+	ehci_doorbell_async(sc);
+
+	/* give the doorbell 4ms */
+	usbd_transfer_timeout_ms(xfer,
+	    (void (*)(void *))&ehci_start_dma_delay_second, 4);
+}
+
 static const struct usb_bus_methods ehci_bus_methods =
 {
 	.endpoint_init = ehci_ep_init,
@@ -3914,4 +3959,5 @@ static const struct usb_bus_methods ehci
 	.set_hw_power_sleep = ehci_set_hw_power_sleep,
 	.roothub_exec = ehci_roothub_exec,
 	.xfer_poll = ehci_do_poll,
+	.start_dma_delay = ehci_start_dma_delay,
 };