usb: dwc2: Disable all EP’s on disconnect [Linux 4.19.64]

This Linux kernel change "usb: dwc2: Disable all EP’s on disconnect" is included in the Linux 4.19.64 release. This change is authored by Minas Harutyunyan <Minas.Harutyunyan [at] synopsys.com> on Wed Sep 19 18:13:52 2018 +0400. The commit for this change in Linux stable tree is ec58bfa (patch) which is from upstream commit dccf1ba. The same Linux upstream change may have been applied to various maintained Linux releases and you can find all Linux releases containing changes from upstream dccf1ba.

usb: dwc2: Disable all EP's on disconnect

commit dccf1bad4be7eaa096c1f3697bd37883f9a08ecb upstream.

Disabling all EP's allow to reset EP's to initial state.
On disconnect disable all EP's instead of just killing
all requests. Because of some platform didn't catch
disconnect event, same stuff added to
dwc2_hsotg_core_init_disconnected() function when USB
reset detected on the bus.

Changed from version 1:
Changed lock acquire flow in dwc2_hsotg_ep_disable()
function.

Signed-off-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There are 30 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/usb/dwc2/gadget.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 03614ef..ed79bdf 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3107,6 +3107,8 @@ static void kill_all_requests(struct dwc2_hsotg *hsotg,
        dwc2_hsotg_txfifo_flush(hsotg, ep->fifo_index);
 }

+static int dwc2_hsotg_ep_disable(struct usb_ep *ep);
+
 /**
  * dwc2_hsotg_disconnect - disconnect service
  * @hsotg: The device state.
@@ -3125,13 +3127,12 @@ void dwc2_hsotg_disconnect(struct dwc2_hsotg *hsotg)
    hsotg->connected = 0;
    hsotg->test_mode = 0;

+   /* all endpoints should be shutdown */
    for (ep = 0; ep < hsotg->num_of_eps; ep++) {
        if (hsotg->eps_in[ep])
-           kill_all_requests(hsotg, hsotg->eps_in[ep],
-                     -ESHUTDOWN);
+           dwc2_hsotg_ep_disable(&hsotg->eps_in[ep]->ep);
        if (hsotg->eps_out[ep])
-           kill_all_requests(hsotg, hsotg->eps_out[ep],
-                     -ESHUTDOWN);
+           dwc2_hsotg_ep_disable(&hsotg->eps_out[ep]->ep);
    }

    call_gadget(hsotg, disconnect);
@@ -3189,13 +3190,23 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
    u32 val;
    u32 usbcfg;
    u32 dcfg = 0;
+   int ep;

    /* Kill any ep0 requests as controller will be reinitialized */
    kill_all_requests(hsotg, hsotg->eps_out[0], -ECONNRESET);

-   if (!is_usb_reset)
+   if (!is_usb_reset) {
        if (dwc2_core_reset(hsotg, true))
            return;
+   } else {
+       /* all endpoints should be shutdown */
+       for (ep = 1; ep < hsotg->num_of_eps; ep++) {
+           if (hsotg->eps_in[ep])
+               dwc2_hsotg_ep_disable(&hsotg->eps_in[ep]->ep);
+           if (hsotg->eps_out[ep])
+               dwc2_hsotg_ep_disable(&hsotg->eps_out[ep]->ep);
+       }
+   }

    /*
     * we must now enable ep0 ready for host detection and then
@@ -3996,6 +4007,7 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
    unsigned long flags;
    u32 epctrl_reg;
    u32 ctrl;
+   int locked;

    dev_dbg(hsotg->dev, "%s(ep %p)\n", __func__, ep);

@@ -4011,7 +4023,9 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)

    epctrl_reg = dir_in ? DIEPCTL(index) : DOEPCTL(index);

-   spin_lock_irqsave(&hsotg->lock, flags);
+   locked = spin_is_locked(&hsotg->lock);
+   if (!locked)
+       spin_lock_irqsave(&hsotg->lock, flags);

    ctrl = dwc2_readl(hsotg, epctrl_reg);

@@ -4035,7 +4049,9 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
    hs_ep->fifo_index = 0;
    hs_ep->fifo_size = 0;

-   spin_unlock_irqrestore(&hsotg->lock, flags);
+   if (!locked)
+       spin_unlock_irqrestore(&hsotg->lock, flags);
+
    return 0;
 }

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