From: "Du, Changbin" <changbin...@intel.com>

Enabling a already enabled ep is illegal, because the ep may has trbs
running. Reprogram the ep may break running transfer. So udc driver
must avoid this happening by return an error -EBUSY. Gadget function
driver also should avoid such things, but that is out of udc driver.

Similarly, disable a disabled ep makes no sense, but no need return
an error here.

Signed-off-by: Du, Changbin <changbin...@intel.com>
---
 drivers/usb/dwc2/core.h   |  1 +
 drivers/usb/dwc2/gadget.c | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index a66d3cb..cf7eccd 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -162,6 +162,7 @@ struct dwc2_hsotg_ep {
        unsigned char           mc;
        unsigned char           interval;
 
+       unsigned int            enabled:1;
        unsigned int            halted:1;
        unsigned int            periodic:1;
        unsigned int            isochronous:1;
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 0abf73c..586bbcd 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -2423,6 +2423,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg 
*hsotg,
        /* enable, but don't activate EP0in */
        dwc2_writel(dwc2_hsotg_ep0_mps(hsotg->eps_out[0]->ep.maxpacket) |
               DXEPCTL_USBACTEP, hsotg->regs + DIEPCTL0);
+       hsotg->eps_out[0]->enabled = 1;
 
        dwc2_hsotg_enqueue_setup(hsotg);
 
@@ -2680,6 +2681,14 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
                return -EINVAL;
        }
 
+       spin_lock_irqsave(&hsotg->lock, flags);
+       if (hs_ep->enabled) {
+               dev_warn(hsotg->dev, "%s: ep %s already enabled\n",
+                       __func__, hs_ep->name);
+               ret = -EBUSY;
+               goto error;
+       }
+
        mps = usb_endpoint_maxp(desc);
 
        /* note, we handle this here instead of dwc2_hsotg_set_ep_maxpacket */
@@ -2690,7 +2699,6 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
        dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x from 0x%08x\n",
                __func__, epctrl, epctrl_reg);
 
-       spin_lock_irqsave(&hsotg->lock, flags);
 
        epctrl &= ~(DXEPCTL_EPTYPE_MASK | DXEPCTL_MPS_MASK);
        epctrl |= DXEPCTL_MPS(mps);
@@ -2806,6 +2814,8 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
        /* enable the endpoint interrupt */
        dwc2_hsotg_ctrl_epint(hsotg, index, dir_in, 1);
 
+       hs_ep->enabled = 1;
+
 error:
        spin_unlock_irqrestore(&hsotg->lock, flags);
        return ret;
@@ -2835,6 +2845,11 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
        epctrl_reg = dir_in ? DIEPCTL(index) : DOEPCTL(index);
 
        spin_lock_irqsave(&hsotg->lock, flags);
+       if (!hs_ep->enabled) {
+               dev_warn(hsotg->dev, "%s: ep %s already disabled\n",
+                       __func__, hs_ep->name);
+               goto out;
+       }
 
        hsotg->fifo_map &= ~(1<<hs_ep->fifo_index);
        hs_ep->fifo_index = 0;
@@ -2854,6 +2869,9 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
        /* terminate all requests with shutdown */
        kill_all_requests(hsotg, hs_ep, -ESHUTDOWN);
 
+       hs_ep->enabled = 0;
+
+out:
        spin_unlock_irqrestore(&hsotg->lock, flags);
        return 0;
 }
-- 
2.5.0

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