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 - 2014, Intel Corporation. All rights reserved.<BR>
   8
   9   SPDX-License-Identifier: BSD-2-Clause-Patent
  10
  11 **/
  12
  13 #include <Library/BaseLib.h>
  14 #include <Library/UefiBootServicesTableLib.h>
  15
  16 #include "VirtioNet.h"
  17
  18 /**
  19   Reads the current interrupt status and recycled transmit buffer status from
  20   a network interface.
  21
  22   @param  This            The protocol instance pointer.
  23   @param  InterruptStatus A pointer to the bit mask of the currently active
  24                           interrupts If this is NULL, the interrupt status will
  25                           not be read from the device. If this is not NULL, the
  26                           interrupt status will be read from the device. When
  27                           the  interrupt status is read, it will also be
  28                           cleared. Clearing the transmit  interrupt does not
  29                           empty the recycled transmit buffer array.
  30   @param  TxBuf           Recycled transmit buffer address. The network
  31                           interface will not transmit if its internal recycled
  32                           transmit buffer array is full. Reading the transmit
  33                           buffer does not clear the transmit interrupt. If this
  34                           is NULL, then the transmit buffer status will not be
  35                           read. If there are no transmit buffers to recycle and
  36                           TxBuf is not NULL, * TxBuf will be set to NULL.
  37
  38   @retval EFI_SUCCESS           The status of the network interface was
  39                                 retrieved.
  40   @retval EFI_NOT_STARTED       The network interface has not been started.
  41   @retval EFI_INVALID_PARAMETER One or more of the parameters has an
  42                                 unsupported value.
  43   @retval EFI_DEVICE_ERROR      The command could not be sent to the network
  44                                 interface.
  45   @retval EFI_UNSUPPORTED       This function is not supported by the network
  46                                 interface.
  47
  48 **/
  49 EFI_STATUS
  50 EFIAPI
  51 VirtioNetGetStatus (
  52   IN EFI_SIMPLE_NETWORK_PROTOCOL  *This,
  53   OUT UINT32                      *InterruptStatus OPTIONAL,
  54   OUT VOID                        **TxBuf OPTIONAL
  55   )
  56 {
  57   VNET_DEV              *Dev;
  58   EFI_TPL               OldTpl;
  59   EFI_STATUS            Status;
  60   UINT16                RxCurUsed;
  61   UINT16                TxCurUsed;
  62   EFI_PHYSICAL_ADDRESS  DeviceAddress;
  63
  64   if (This == NULL) {
  65     return EFI_INVALID_PARAMETER;
  66   }
  67
  68   Dev    = VIRTIO_NET_FROM_SNP (This);
  69   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
  70   switch (Dev->Snm.State) {
  71     case EfiSimpleNetworkStopped:
  72       Status = EFI_NOT_STARTED;
  73       goto Exit;
  74     case EfiSimpleNetworkStarted:
  75       Status = EFI_DEVICE_ERROR;
  76       goto Exit;
  77     default:
  78       break;
  79   }
  80
  81   //
  82   // update link status
  83   //
  84   if (Dev->Snm.MediaPresentSupported) {
  85     UINT16  LinkStatus;
  86
  87     Status = VIRTIO_CFG_READ (Dev, LinkStatus, &LinkStatus);
  88     if (EFI_ERROR (Status)) {
  89       goto Exit;
  90     }
  91
  92     Dev->Snm.MediaPresent =
  93       (BOOLEAN)((LinkStatus & VIRTIO_NET_S_LINK_UP) != 0);
  94   }
  95
  96   //
  97   // virtio-0.9.5, 2.4.2 Receiving Used Buffers From the Device
  98   //
  99   MemoryFence ();
 100   RxCurUsed = *Dev->RxRing.Used.Idx;
 101   TxCurUsed = *Dev->TxRing.Used.Idx;
 102   MemoryFence ();
 103
 104   if (InterruptStatus != NULL) {
 105     //
 106     // report the receive interrupt if there is data available for reception,
 107     // report the transmit interrupt if we have transmitted at least one buffer
 108     //
 109     *InterruptStatus = 0;
 110     if (Dev->RxLastUsed != RxCurUsed) {
 111       *InterruptStatus |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
 112     }
 113
 114     if (Dev->TxLastUsed != TxCurUsed) {
 115       ASSERT (Dev->TxCurPending > 0);
 116       *InterruptStatus |= EFI_SIMPLE_NETWORK_TRANSMIT_INTERRUPT;
 117     }
 118   }
 119
 120   if (TxBuf != NULL) {
 121     if (Dev->TxLastUsed == TxCurUsed) {
 122       *TxBuf = NULL;
 123     } else {
 124       UINT16  UsedElemIdx;
 125       UINT32  DescIdx;
 126
 127       //
 128       // fetch the first descriptor among those that the hypervisor reports
 129       // completed
 130       //
 131       ASSERT (Dev->TxCurPending > 0);
 132       ASSERT (Dev->TxCurPending <= Dev->TxMaxPending);
 133
 134       UsedElemIdx = Dev->TxLastUsed++ % Dev->TxRing.QueueSize;
 135       DescIdx     = Dev->TxRing.Used.UsedElem[UsedElemIdx].Id;
 136       ASSERT (DescIdx < (UINT32)(2 * Dev->TxMaxPending - 1));
 137
 138       //
 139       // get the device address that has been enqueued for the caller's
 140       // transmit buffer
 141       //
 142       DeviceAddress = Dev->TxRing.Desc[DescIdx + 1].Addr;
 143
 144       //
 145       // now this descriptor can be used again to enqueue a transmit buffer
 146       //
 147       Dev->TxFreeStack[--Dev->TxCurPending] = (UINT16)DescIdx;
 148
 149       //
 150       // Unmap the device address and perform the reverse mapping to find the
 151       // caller buffer address.
 152       //
 153       Status = VirtioNetUnmapTxBuf (
 154                  Dev,
 155                  TxBuf,
 156                  DeviceAddress
 157                  );
 158       if (EFI_ERROR (Status)) {
 159         //
 160         // VirtioNetUnmapTxBuf should never fail, if we have reached here
 161         // that means our internal state has been corrupted
 162         //
 163         ASSERT (FALSE);
 164         Status = EFI_DEVICE_ERROR;
 165         goto Exit;
 166       }
 167     }
 168   }
 169
 170   Status = EFI_SUCCESS;
 171
 172 Exit:
 173   gBS->RestoreTPL (OldTpl);
 174   return Status;
 175 }