OvmfPkg/VirtioNetDxe/SnpGetStatus.c

   1 /** @file
   2
   3   Implementation of the SNP.GetStatus() function and its private helpers if
   4   any.
   5
   6   Copyright (C) 2013, Red Hat, Inc.
   7   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   8
   9   This program and the accompanying materials are licensed and made available
  10   under the terms and conditions of the BSD License which accompanies this
  11   distribution. The full text of the license may be found at
  12   http://opensource.org/licenses/bsd-license.php
  13
  14   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  15   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  16
  17 **/
  18
  19 #include <Library/BaseLib.h>
  20 #include <Library/UefiBootServicesTableLib.h>
  21
  22 #include "VirtioNet.h"
  23
  24 /**
  25   Reads the current interrupt status and recycled transmit buffer status from
  26   a network interface.
  27
  28   @param  This            The protocol instance pointer.
  29   @param  InterruptStatus A pointer to the bit mask of the currently active
  30                           interrupts If this is NULL, the interrupt status will
  31                           not be read from the device. If this is not NULL, the
  32                           interrupt status will be read from the device. When
  33                           the  interrupt status is read, it will also be
  34                           cleared. Clearing the transmit  interrupt does not
  35                           empty the recycled transmit buffer array.
  36   @param  TxBuf           Recycled transmit buffer address. The network
  37                           interface will not transmit if its internal recycled
  38                           transmit buffer array is full. Reading the transmit
  39                           buffer does not clear the transmit interrupt. If this
  40                           is NULL, then the transmit buffer status will not be
  41                           read. If there are no transmit buffers to recycle and
  42                           TxBuf is not NULL, * TxBuf will be set to NULL.
  43
  44   @retval EFI_SUCCESS           The status of the network interface was
  45                                 retrieved.
  46   @retval EFI_NOT_STARTED       The network interface has not been started.
  47   @retval EFI_INVALID_PARAMETER One or more of the parameters has an
  48                                 unsupported value.
  49   @retval EFI_DEVICE_ERROR      The command could not be sent to the network
  50                                 interface.
  51   @retval EFI_UNSUPPORTED       This function is not supported by the network
  52                                 interface.
  53
  54 **/
  55
  56 EFI_STATUS
  57 EFIAPI
  58 VirtioNetGetStatus (
  59   IN EFI_SIMPLE_NETWORK_PROTOCOL *This,
  60   OUT UINT32                     *InterruptStatus OPTIONAL,
  61   OUT VOID                       **TxBuf OPTIONAL
  62   )
  63 {
  64   VNET_DEV   *Dev;
  65   EFI_TPL    OldTpl;
  66   EFI_STATUS Status;
  67   UINT16     RxCurUsed;
  68   UINT16     TxCurUsed;
  69
  70   if (This == NULL) {
  71     return EFI_INVALID_PARAMETER;
  72   }
  73
  74   Dev = VIRTIO_NET_FROM_SNP (This);
  75   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
  76   switch (Dev->Snm.State) {
  77   case EfiSimpleNetworkStopped:
  78     Status = EFI_NOT_STARTED;
  79     goto Exit;
  80   case EfiSimpleNetworkStarted:
  81     Status = EFI_DEVICE_ERROR;
  82     goto Exit;
  83   default:
  84     break;
  85   }
  86
  87   //
  88   // update link status
  89   //
  90   if (Dev->Snm.MediaPresentSupported) {
  91     UINT16 LinkStatus;
  92
  93     Status = VIRTIO_CFG_READ (Dev, VhdrLinkStatus, &LinkStatus);
  94     if (EFI_ERROR (Status)) {
  95       goto Exit;
  96     }
  97     Dev->Snm.MediaPresent = !!(LinkStatus & VIRTIO_NET_S_LINK_UP);
  98   }
  99
 100   //
 101   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
 102   //
 103   MemoryFence ();
 104   RxCurUsed = *Dev->RxRing.Used.Idx;
 105   TxCurUsed = *Dev->TxRing.Used.Idx;
 106
 107   if (InterruptStatus != NULL) {
 108     //
 109     // report the receive interrupt if there is data available for reception,
 110     // report the transmit interrupt if we have transmitted at least one buffer
 111     //
 112     *InterruptStatus = 0;
 113     if (Dev->RxLastUsed != RxCurUsed) {
 114       *InterruptStatus |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
 115     }
 116     if (Dev->TxLastUsed != TxCurUsed) {
 117       ASSERT (Dev->TxCurPending > 0);
 118       *InterruptStatus |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
 119     }
 120   }
 121
 122   if (TxBuf != NULL) {
 123     if (Dev->TxLastUsed == TxCurUsed) {
 124       *TxBuf = NULL;
 125     }
 126     else {
 127       UINT16 UsedElemIdx;
 128       UINT32 DescIdx;
 129
 130       //
 131       // fetch the first descriptor among those that the hypervisor reports
 132       // completed
 133       //
 134       ASSERT (Dev->TxCurPending > 0);
 135       ASSERT (Dev->TxCurPending <= Dev->TxMaxPending);
 136
 137       UsedElemIdx = Dev->TxLastUsed++ % Dev->TxRing.QueueSize;
 138       DescIdx = Dev->TxRing.Used.UsedElem[UsedElemIdx].Id;
 139       ASSERT (DescIdx < 2 * Dev->TxMaxPending - 1);
 140
 141       //
 142       // report buffer address to caller that has been enqueued by caller
 143       //
 144       *TxBuf = (VOID *) Dev->TxRing.Desc[DescIdx + 1].Addr;
 145
 146       //
 147       // now this descriptor can be used again to enqueue a transmit buffer
 148       //
 149       Dev->TxFreeStack[--Dev->TxCurPending] = (UINT16) DescIdx;
 150     }
 151   }
 152
 153   Status = EFI_SUCCESS;
 154
 155 Exit:
 156   gBS->RestoreTPL (OldTpl);
 157   return Status;
 158 }