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usb: dwc3: core: Do not perform GCTL_CORE_SOFTRESET during bootup
authorRohith Kollalsi <quic_rkollals@quicinc.com>
Thu, 14 Jul 2022 04:56:25 +0000 (10:26 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 14 Jul 2022 14:10:30 +0000 (16:10 +0200)
commit07903626d98853e605fe63e5ce149f1b7314bbea
treeba3f577572a80e6869de47c20c193502563f206a
parent220fafb4ed04187e9c17be4152da5a7f2ffbdd8c
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: 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>
drivers/usb/dwc3/core.c