Fix infinite loop in CDC/ACM driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4655 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -2681,4 +2681,9 @@
 	  PIC32MX7 Multimedia Board (MMB).
 	* net/recvfrom.c:  Fix a compilation problem.  Some UDP logic was conditioned
 	  on TCP, not UDP.
+	* drivers/usbdev/cdcacm.c: Fix an infinite loop that occurs when the serial
+	  device is unregisters.
+	* arch/arm/src/stm32/stm32_otgfs.c: The driver needs to reset the software (in
+	  order to flush the requests) and to disable the software connection when the
+	  device is unregistered.
 

arch/arm/src/stm32/stm32_otgfsdev.c

@@ -1870,6 +1870,7 @@ static void stm32_usbreset(struct stm32_usbdev_s *priv)
 
       privep->stalled = false;
     }
+
   stm32_putreg(0xffffffff, STM32_OTGFS_DAINT);
 
   /* Mask all device endpoint interrupts except EP0 */
@@ -5283,6 +5284,7 @@ int usbdev_unregister(struct usbdevclass_driver_s *driver)
    */
 
   FAR struct stm32_usbdev_s *priv = &g_otgfsdev;
+  irqstate_t flags;
 
   usbtrace(TRACE_DEVUNREGISTER, 0);
 
@@ -5294,6 +5296,13 @@ int usbdev_unregister(struct usbdevclass_driver_s *driver)
     }
 #endif
 
+  /* Reset the hardware and cancel all requests.  All requests must be
+   * canceled while the class driver is still bound.
+   */
+
+  flags = irqsave();
+  stm32_usbreset(priv);
+
   /* Unbind the class driver */
 
   CLASS_UNBIND(driver, &priv->usbdev);
@@ -5302,9 +5311,15 @@ int usbdev_unregister(struct usbdevclass_driver_s *driver)
 
   up_disable_irq(STM32_IRQ_OTGFS);
 
+  /* Disconnect device */
+
+  stm32_pullup(&priv->usbdev, false);
+
   /* Unhook the driver */
 
   priv->driver = NULL;
+  irqrestore(flags);
+
   return OK;
 }
 

drivers/usbdev/cdcacm.c

@@ -2182,14 +2182,16 @@ void cdcacm_uninitialize(FAR void *handle)
       usbtrace(TRACE_CLSERROR(USBSER_TRACEERR_UARTUNREGISTER), (uint16_t)-ret);
     }
 
-  /* Unbind the class (if still bound) */
-
-  if (priv->usbdev)
-    {
-       cdcacm_unbind(&drvr->drvr, priv->usbdev);
-    }
-
-  /* Unregister the driver (unless we are a part of a composite device) */
+  /* Unregister the driver (unless we are a part of a composite device).  The
+   * device unregister logic will (1) return all of the requests to us then
+   * (2) all the unbind method.
+   *
+   * The same thing will happen in the composite case except that: (1) the
+   * composite driver will call usbdev_unregister() which will (2) return the
+   * requests for all members of the composite, and (3) call the unbind
+   * method in the composite device which will (4) call the unbind method
+   * for this device.
+   */
 
 #ifndef CONFIG_CDCACM_COMPOSITE
   usbdev_unregister(&drvr->drvr);