OvmfPkg/VirtioNetDxe/Events.c

   1 /** @file
   2
   3   Implements
   4   - the SNM.WaitForPacket EVT_NOTIFY_WAIT event,
   5   - the EVT_SIGNAL_EXIT_BOOT_SERVICES event
   6   for the virtio-net driver.
   7
   8   Copyright (C) 2013, Red Hat, Inc.
   9   Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
  10
  11   SPDX-License-Identifier: BSD-2-Clause-Patent
  12
  13 **/
  14
  15 #include <Library/BaseLib.h>
  16 #include <Library/UefiBootServicesTableLib.h>
  17
  18 #include "VirtioNet.h"
  19
  20 /**
  21   Invoke a notification event
  22
  23   @param  Event                 Event whose notification function is being
  24                                 invoked.
  25   @param  Context               The pointer to the notification function's
  26                                 context, which is implementation-dependent.
  27
  28 **/
  29
  30 VOID
  31 EFIAPI
  32 VirtioNetIsPacketAvailable (
  33   IN  EFI_EVENT Event,
  34   IN  VOID      *Context
  35   )
  36 {
  37   //
  38   // This callback has been enqueued by an external application and is
  39   // running at TPL_CALLBACK already.
  40   //
  41   // The WaitForPacket logic is similar to that of WaitForKey. The former has
  42   // almost no documentation in either the UEFI-2.3.1+errC spec or the
  43   // DWG-2.3.1, but WaitForKey does have some.
  44   //
  45   VNET_DEV *Dev;
  46   UINT16   RxCurUsed;
  47
  48   Dev = Context;
  49   if (Dev->Snm.State != EfiSimpleNetworkInitialized) {
  50     return;
  51   }
  52
  53   //
  54   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
  55   //
  56   MemoryFence ();
  57   RxCurUsed = *Dev->RxRing.Used.Idx;
  58   MemoryFence ();
  59
  60   if (Dev->RxLastUsed != RxCurUsed) {
  61     gBS->SignalEvent (&Dev->Snp.WaitForPacket);
  62   }
  63 }
  64
  65 VOID
  66 EFIAPI
  67 VirtioNetExitBoot (
  68   IN  EFI_EVENT Event,
  69   IN  VOID      *Context
  70   )
  71 {
  72   //
  73   // This callback has been enqueued by ExitBootServices() and is running at
  74   // TPL_CALLBACK already.
  75   //
  76   // Shut down pending transfers according to DWG-2.3.1, "25.5.1 Exit Boot
  77   // Services Event".
  78   //
  79   VNET_DEV *Dev;
  80
  81   DEBUG ((DEBUG_VERBOSE, "%a: Context=0x%p\n", __FUNCTION__, Context));
  82   Dev = Context;
  83   if (Dev->Snm.State == EfiSimpleNetworkInitialized) {
  84     Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
  85   }
  86 }