From c40cf7705e13d288d900e044c0a2f756e9e4909a Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 16 Apr 2019 14:53:49 -0700 Subject: usb: dwc2: optionally assert phy reset when waking up On the rk3288 USB host-only port (the one that's not the OTG-enabled port) the PHY can get into a bad state when a wakeup is asserted (not just a wakeup from full system suspend but also a wakeup from autosuspend). We can get the PHY out of its bad state by asserting its "port reset", but unfortunately that seems to assert a reset onto the USB bus so it could confuse things if we don't actually deenumerate / reenumerate the device. We can also get the PHY out of its bad state by fully resetting it using the reset from the CRU (clock reset unit), which does a more full reset. The CRU-based reset appears to actually cause devices on the bus to be removed and reinserted, which fixes the problem (albeit in a hacky way). It's unfortunate that we need to do a full re-enumeration of devices at wakeup time, but this is better than alternative of letting the bus get wedged. Signed-off-by: Douglas Anderson Signed-off-by: Yunzhi Li Signed-off-by: Felipe Balbi --- drivers/usb/dwc2/core_intr.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/usb/dwc2/core_intr.c') diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c index 19ae2595f1c3..6af6add3d4c0 100644 --- a/drivers/usb/dwc2/core_intr.c +++ b/drivers/usb/dwc2/core_intr.c @@ -435,6 +435,18 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg) /* Restart the Phy Clock */ pcgcctl &= ~PCGCTL_STOPPCLK; dwc2_writel(hsotg, pcgcctl, PCGCTL); + + /* + * If we've got this quirk then the PHY is stuck upon + * wakeup. Assert reset. This will propagate out and + * eventually we'll re-enumerate the device. Not great + * but the best we can do. We can't call phy_reset() + * at interrupt time but there's no hurry, so we'll + * schedule it for later. + */ + if (hsotg->reset_phy_on_wake) + dwc2_host_schedule_phy_reset(hsotg); + mod_timer(&hsotg->wkp_timer, jiffies + msecs_to_jiffies(71)); } else { -- cgit v1.2.3