When cdns3_gadget_start() fails, the DRD hardware is left in gadget mode
while software state remains INACTIVE, creating hardware/software state
inconsistency.

When switching to host mode via sysfs:
  echo host > /sys/class/usb_role/13180000.usb-role-switch/role

The role state is not set to CDNS_ROLE_STATE_ACTIVE due to the error,
so cdns_role_stop() skips cleanup because state is still INACTIVE.
This violates the DRD controller design specification (Figure22),
which requires returning to idle state before switching roles.

This leads to a synchronous external abort in xhci_gen_setup() when
setting up the host controller:

[  516.440698] configfs-gadget 13180000.usb: failed to start g1: -19
[  516.442035] cdns-usb3 13180000.usb: Failed to add gadget
[  516.443278] cdns-usb3 13180000.usb: set role 2 has failed
...
[ 1301.375722] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller
[ 1301.377716] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
[ 1301.382485] pc : xhci_gen_setup+0xa4/0x408
[ 1301.393391] backtrace:
    ...
    xhci_gen_setup+0xa4/0x408    <-- CRASH
    xhci_plat_setup+0x44/0x58
    usb_add_hcd+0x284/0x678
    ...
    cdns_role_set+0x9c/0xbc        <-- Role switch

Fix by calling cdns_drd_gadget_off() in the error path to properly
clean up the DRD gadget state.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Cc: stable@kernel.org
Signed-off-by: Yongchao Wu <yongchao.wu@autochips.com>

---
Changes in v2:
  - Update commit title to reflect state inconsistency
  - Add more detailed description with error logs
  - Add Fixes tag and Cc to stable
---
 drivers/usb/cdns3/cdns3-gadget.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index d59a60a16..4cc3f2ffb 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -3428,6 +3428,7 @@ static int __cdns3_gadget_init(struct cdns *cdns)
 	ret = cdns3_gadget_start(cdns);
 	if (ret) {
 		pm_runtime_put_sync(cdns->dev);
+		cdns_drd_gadget_off(cdns);
 		return ret;
 	}
 
-- 
2.43.0