CHROMIUM: xhci: stop roothub port polling timer in shutdown

The xhci hcd use the port polling timer (rh_timer) to poll the
roothub for port events. But we can't allow the USB core to poll
the port events during shutdown because the xhci controller may
be disable and can't be accessed in shutdown. If we access xhci
port registers with port polling timer after xhci shutdown, it
may cause kernel crash or unexpected behavior. So we need to stop
the port polling timer while shutdown xhci.

I can easily reproduce the issue on rk3399 platform, plug in a
Type-C hub and an USB ethernet dongle, then do reboot test,
result in a crash with the following backtrace.

Unhandled fault: synchronous external abort (0x96000010) at 0xffffff80002f0430
Internal error: : 96000010 [#1] PREEMPT SMP
task: ffffffc001092cb0 ti: ffffffc00107c000 task.ti: ffffffc00107c000
PC is at xhci_hub_status_data+0xec/0x1e4
LR is at xhci_hub_status_data+0xb0/0x1e4
[<ffffffc00067a210>] xhci_hub_status_data+0xec/0x1e4
[<ffffffc00063ebf8>] usb_hcd_poll_rh_status+0x54/0x148
[<ffffffc00063ed0c>] rh_timer_func+0x20/0x2c
[<ffffffc0002845cc>] call_timer_fn+0xa4/0x1c8
[<ffffffc000284964>] run_timer_softirq+0x248/0x2cc
[<ffffffc000200928>] __do_softirq+0x178/0x338
[<ffffffc000224b08>] irq_exit+0x78/0xc0
[<ffffffc00027089c>] __handle_domain_irq+0x9c/0xbc
[<ffffffc0002006f4>] gic_handle_irq+0xcc/0x188

BUG=chrome-os-partner:59111
TEST=Plug in a Type-C hub, then do reboot test, check if
kernel crash during shutdown.

Change-Id: I3ca3d12d101241cd78138ea5d995708a2893d1a0
Signed-off-by: William wu <wulf@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/401121
Commit-Ready: Guenter Roeck <groeck@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 0b48f7d97ddf433aba70912fe766b1d93d7809e1..6373f159de12486bb7c8c37f967a07424d29ed40 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -744,6 +744,12 @@ void xhci_shutdown(struct usb_hcd *hcd)
        if (!hcd->rh_registered)
                return;
 
+       /* Don't poll the roothubs on shutdown */
+       clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
+       del_timer_sync(&hcd->rh_timer);
+       clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
+       del_timer_sync(&xhci->shared_hcd->rh_timer);
+
        if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
                usb_disable_xhci_ports(to_pci_dev(hcd->self.controller));