usb: core: hcd: Add support for deferring roothub registration

commit 58877b0824da15698bd85a0a9dbfa8c354e6ecb7 upstream.

It has been observed with certain PCIe USB cards (like Inateck connected
to AM64 EVM or J7200 EVM) that as soon as the primary roothub is
registered, port status change is handled even before xHC is running
leading to cold plug USB devices not detected. For such cases, registering
both the root hubs along with the second HCD is required. Add support for
deferring roothub registration in usb_add_hcd(), so that both primary and
secondary roothubs are registered along with the second HCD.

CC: stable@vger.kernel.org # 5.4+
Suggested-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Tested-by: Chris Chiu <chris.chiu@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Link: https://lore.kernel.org/r/20210909064200.16216-2-kishon@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 99908d8d2dd36d5e9018257883e7d7969385d9ee..4bbf3316a9a53164f276ba112533bd866f7bf1de 100644 (file)
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2640,6 +2640,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
 {
        int retval;
        struct usb_device *rhdev;
+       struct usb_hcd *shared_hcd;
 
        if (!hcd->skip_phy_initialization && usb_hcd_is_primary_hcd(hcd)) {
                hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
@@ -2796,13 +2797,26 @@ int usb_add_hcd(struct usb_hcd *hcd,
                goto err_hcd_driver_start;
        }
 
+       /* starting here, usbcore will pay attention to the shared HCD roothub */
+       shared_hcd = hcd->shared_hcd;
+       if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd)) {
+               retval = register_root_hub(shared_hcd);
+               if (retval != 0)
+                       goto err_register_root_hub;
+
+               if (shared_hcd->uses_new_polling && HCD_POLL_RH(shared_hcd))
+                       usb_hcd_poll_rh_status(shared_hcd);
+       }
+
        /* starting here, usbcore will pay attention to this root hub */
-       retval = register_root_hub(hcd);
-       if (retval != 0)
-               goto err_register_root_hub;
+       if (!HCD_DEFER_RH_REGISTER(hcd)) {
+               retval = register_root_hub(hcd);
+               if (retval != 0)
+                       goto err_register_root_hub;
 
-       if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
-               usb_hcd_poll_rh_status(hcd);
+               if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
+                       usb_hcd_poll_rh_status(hcd);
+       }
 
        return retval;
 
@@ -2845,6 +2859,7 @@ EXPORT_SYMBOL_GPL(usb_add_hcd);
 void usb_remove_hcd(struct usb_hcd *hcd)
 {
        struct usb_device *rhdev = hcd->self.root_hub;
+       bool rh_registered;
 
        dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);
 
@@ -2855,6 +2870,7 @@ void usb_remove_hcd(struct usb_hcd *hcd)
 
        dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
        spin_lock_irq (&hcd_root_hub_lock);
+       rh_registered = hcd->rh_registered;
        hcd->rh_registered = 0;
        spin_unlock_irq (&hcd_root_hub_lock);
 
@@ -2864,7 +2880,8 @@ void usb_remove_hcd(struct usb_hcd *hcd)
        cancel_work_sync(&hcd->died_work);
 
        mutex_lock(&usb_bus_idr_lock);
-       usb_disconnect(&rhdev);         /* Sets rhdev to NULL */
+       if (rh_registered)
+               usb_disconnect(&rhdev);         /* Sets rhdev to NULL */
        mutex_unlock(&usb_bus_idr_lock);
 
        /*

diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 3dbb42c637c142d0652ccc33dd8d6814a6706ef5..9f05016d823f80cf584b9d957bd987db2ceac8c5 100644 (file)
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -124,6 +124,7 @@ struct usb_hcd {
 #define HCD_FLAG_RH_RUNNING            5       /* root hub is running? */
 #define HCD_FLAG_DEAD                  6       /* controller has died? */
 #define HCD_FLAG_INTF_AUTHORIZED       7       /* authorize interfaces? */
+#define HCD_FLAG_DEFER_RH_REGISTER     8       /* Defer roothub registration */
 
        /* The flags can be tested using these macros; they are likely to
         * be slightly faster than test_bit().
@@ -134,6 +135,7 @@ struct usb_hcd {
 #define HCD_WAKEUP_PENDING(hcd)        ((hcd)->flags & (1U << HCD_FLAG_WAKEUP_PENDING))
 #define HCD_RH_RUNNING(hcd)    ((hcd)->flags & (1U << HCD_FLAG_RH_RUNNING))
 #define HCD_DEAD(hcd)          ((hcd)->flags & (1U << HCD_FLAG_DEAD))
+#define HCD_DEFER_RH_REGISTER(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEFER_RH_REGISTER))
 
        /*
         * Specifies if interfaces are authorized by default