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   This program and the accompanying materials are licensed and made available
  12   under the terms and conditions of the BSD License which accompanies this
  13   distribution. The full text of the license may be found at
  14   http://opensource.org/licenses/bsd-license.php
  15
  16   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  17   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  18
  19 **/
  20
  21 #include <Library/BaseLib.h>
  22 #include <Library/UefiBootServicesTableLib.h>
  23
  24 #include "VirtioNet.h"
  25
  26 /**
  27   Invoke a notification event
  28
  29   @param  Event                 Event whose notification function is being
  30                                 invoked.
  31   @param  Context               The pointer to the notification function's
  32                                 context, which is implementation-dependent.
  33
  34 **/
  35
  36 VOID
  37 EFIAPI
  38 VirtioNetIsPacketAvailable (
  39   IN  EFI_EVENT Event,
  40   IN  VOID      *Context
  41   )
  42 {
  43   //
  44   // This callback has been enqueued by an external application and is
  45   // running at TPL_CALLBACK already.
  46   //
  47   // The WaitForPacket logic is similar to that of WaitForKey. The former has
  48   // almost no documentation in either the UEFI-2.3.1+errC spec or the
  49   // DWG-2.3.1, but WaitForKey does have some.
  50   //
  51   VNET_DEV *Dev;
  52   UINT16   RxCurUsed;
  53
  54   Dev = Context;
  55   if (Dev->Snm.State != EfiSimpleNetworkInitialized) {
  56     return;
  57   }
  58
  59   //
  60   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
  61   //
  62   MemoryFence ();
  63   RxCurUsed = *Dev->RxRing.Used.Idx;
  64   MemoryFence ();
  65
  66   if (Dev->RxLastUsed != RxCurUsed) {
  67     gBS->SignalEvent (&Dev->Snp.WaitForPacket);
  68   }
  69 }
  70
  71 VOID
  72 EFIAPI
  73 VirtioNetExitBoot (
  74   IN  EFI_EVENT Event,
  75   IN  VOID      *Context
  76   )
  77 {
  78   //
  79   // This callback has been enqueued by ExitBootServices() and is running at
  80   // TPL_CALLBACK already.
  81   //
  82   // Shut down pending transfers according to DWG-2.3.1, "25.5.1 Exit Boot
  83   // Services Event".
  84   //
  85   VNET_DEV *Dev;
  86
  87   DEBUG ((DEBUG_VERBOSE, "%a: Context=0x%p\n", __FUNCTION__, Context));
  88   Dev = Context;
  89   if (Dev->Snm.State == EfiSimpleNetworkInitialized) {
  90     Dev->VirtIo->SetDeviceStatus (Dev->VirtIo, 0);
  91   }
  92 }