[PATCH 5.16 129/164] usb: dwc2: drd: fix soft connect when gadget is unconfigured

Greg Kroah-Hartman
2022-02-28T18:11:52Z

From: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

commit 32fde84362c40961726a5c91f35ad37355ccc0c6 upstream.

When the gadget driver hasn't been (yet) configured, and the cable is
connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
HOST tries to enumerate it.
At the host side, this can result in a stuck USB port or worse. When
getting lucky, some dmesg can be observed at the host side:
new high-speed USB device number ...
device descriptor read/64, error -110

Fix it in drd, by checking the enabled flag before calling
dwc2_hsotg_core_connect(). It will be called later, once configured,
by the normal flow:
- udc_bind_to_driver
- usb_gadget_connect
- dwc2_hsotg_pullup
- dwc2_hsotg_core_connect

Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/1644999135-13478-1-git-send-email-fabrice.gasnier@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/dwc2/core.h | 2 ++
drivers/usb/dwc2/drd.c | 6 ++++--
2 files changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -1416,6 +1416,7 @@ void dwc2_hsotg_core_connect(struct dwc2
void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
#define dwc2_is_device_connected(hsotg) (hsotg->connected)
+#define dwc2_is_device_enabled(hsotg) (hsotg->enabled)
int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg);
int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg, int remote_wakeup);
int dwc2_gadget_enter_hibernation(struct dwc2_hsotg *hsotg);
@@ -1452,6 +1453,7 @@ static inline int dwc2_hsotg_set_test_mo
int testmode)
{ return 0; }
#define dwc2_is_device_connected(hsotg) (0)
+#define dwc2_is_device_enabled(hsotg) (0)
static inline int dwc2_backup_device_registers(struct dwc2_hsotg *hsotg)
{ return 0; }
static inline int dwc2_restore_device_registers(struct dwc2_hsotg *hsotg,
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -109,8 +109,10 @@ static int dwc2_drd_role_sw_set(struct u
already = dwc2_ovr_avalid(hsotg, true);
} else if (role == USB_ROLE_DEVICE) {
already = dwc2_ovr_bvalid(hsotg, true);
- /* This clear DCTL.SFTDISCON bit */
- dwc2_hsotg_core_connect(hsotg);
+ if (dwc2_is_device_enabled(hsotg)) {
+ /* This clear DCTL.SFTDISCON bit */
+ dwc2_hsotg_core_connect(hsotg);
+ }
} else {
if (dwc2_is_device_mode(hsotg)) {
if (!dwc2_ovr_bvalid(hsotg, false))