Commit 07903626 authored by Rohith Kollalsi's avatar Rohith Kollalsi Committed by Greg Kroah-Hartman
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usb: dwc3: core: Do not perform GCTL_CORE_SOFTRESET during bootup 



According to the programming guide, it is recommended to
perform a GCTL_CORE_SOFTRESET only when switching the mode
from device to host or host to device. However, it is found
that during bootup when __dwc3_set_mode() is called for the
first time, GCTL_CORESOFTRESET is done with suspendable bit(BIT 17)
of DWC3_GUSB3PIPECTL set. This some times leads to issues
like controller going into bad state and controller registers
reading value zero. Until GCTL_CORESOFTRESET is done and
run/stop bit is set core initialization is not complete.
Setting suspendable bit of DWC3_GUSB3PIPECTL and then
performing GCTL_CORESOFTRESET is therefore not recommended.
Avoid this by only performing the reset if current_dr_role is set,
that is, when doing subsequent role switching.

Fixes: f88359e1 ("usb: dwc3: core: Do core softreset when switch mode")
Signed-off-by: default avatarRohith Kollalsi <quic_rkollals@quicinc.com>
Link: https://lore.kernel.org/r/20220714045625.20377-1-quic_rkollals@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 220fafb4

drivers/usb/dwc3/core.c

+7 −3
Original line number Diff line number Diff line
@@ -158,9 +158,13 @@ static void __dwc3_set_mode(struct work_struct *work) 
		break;

	}



	/* For DRD host or device mode only */

	if ((DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC31, 190A)) &&

	    dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG) {

	/*

	 * When current_dr_role is not set, there's no role switching.

	 * Only perform GCTL.CoreSoftReset when there's DRD role switching.

	 */

	if (dwc->current_dr_role && ((DWC3_IP_IS(DWC3) ||

			DWC3_VER_IS_PRIOR(DWC31, 190A)) &&

			dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG)) {

		reg = dwc3_readl(dwc->regs, DWC3_GCTL);

		reg |= DWC3_GCTL_CORESOFTRESET;

		dwc3_writel(dwc->regs, DWC3_GCTL, reg);