From: Rohith Kollalsi quic_rkollals@quicinc.com
[ Upstream commit 07903626d98853e605fe63e5ce149f1b7314bbea ]
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: f88359e1588b ("usb: dwc3: core: Do core softreset when switch mode") Signed-off-by: Rohith Kollalsi quic_rkollals@quicinc.com Link: https://lore.kernel.org/r/20220714045625.20377-1-quic_rkollals@quicinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/dwc3/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 46a3b8941e40..ecec9cdfa0a6 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -157,9 +157,13 @@ 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);