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Issue doorbell twice before finally freeing the DMA descriptors. This

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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
This commit is contained in:
hselasky 2014-02-12 08:04:38 +00:00
parent 29185a5d58
commit cdbc178e94
1 changed files with 54 additions and 8 deletions
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62
sys/dev/usb/controller/ehci.c
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@ -2260,11 +2260,27 @@ ehci_device_bulk_enter(struct usb_xfer *xfer)
return;
}
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 *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_bus_methods =
.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,
};