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FROMGIT: usb: dwc3: core: Do not perform GCTL_CORE_SOFTRESET during bootup

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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>

 (cherry picked from commit 07903626d98853e605fe63e5ce149f1b7314bbea
 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/
 usb-next)

BUG: 239121944
Change-Id: Ice6da5dd64896d5deeab425dd1ac5389425a1cc8
Signed-off-by: Rohith Kollalsi <quic_rkollals@quicinc.com>
This commit is contained in:
Rohith Kollalsi
2022-07-15 11:56:27 +05:30
committed by Treehugger Robot
parent 8b19ed264b
commit c301d142e8
1 changed files with 7 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/usb/dwc3/core.c
View File

@@ -156,9 +156,13 @@ static void __dwc3_set_mode(struct work_struct *work)
break; break;
} }
/* For DRD host or device mode only */ /*
if ((DWC3_IP_IS(DWC3) || DWC3_VER_IS_PRIOR(DWC31, 190A)) && * When current_dr_role is not set, there's no role switching.
dwc->desired_dr_role != DWC3_GCTL_PRTCAP_OTG) { * 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_readl(dwc->regs, DWC3_GCTL);
reg |= DWC3_GCTL_CORESOFTRESET; reg |= DWC3_GCTL_CORESOFTRESET;
dwc3_writel(dwc->regs, DWC3_GCTL, reg); dwc3_writel(dwc->regs, DWC3_GCTL, reg);