OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c

   1 /** @file
   2   OVMF's instance of the PCI Host Bridge Library.
   3
   4   Copyright (C) 2016, Red Hat, Inc.
   5   Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
   6
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php.
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  13   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16 #include <PiDxe.h>
  17
  18 #include <IndustryStandard/Pci.h>
  19
  20 #include <Library/DebugLib.h>
  21 #include <Library/MemoryAllocationLib.h>
  22 #include <Library/PciHostBridgeLib.h>
  23 #include <Library/PciLib.h>
  24 #include <Library/QemuFwCfgLib.h>
  25
  26
  27 GLOBAL_REMOVE_IF_UNREFERENCED
  28 CHAR16 *mPciHostBridgeLibAcpiAddressSpaceTypeStr[] = {
  29   L"Mem", L"I/O", L"Bus"
  30 };
  31
  32
  33 /**
  34   Initialize a PCI_ROOT_BRIDGE structure.
  35
  36   param[in]  RootBusNumber     The bus number to store in RootBus.
  37
  38   param[in]  MaxSubBusNumber   The inclusive maximum bus number that can be
  39                                assigned to any subordinate bus found behind any
  40                                PCI bridge hanging off this root bus.
  41
  42                                The caller is repsonsible for ensuring that
  43                                RootBusNumber <= MaxSubBusNumber. If
  44                                RootBusNumber equals MaxSubBusNumber, then the
  45                                root bus has no room for subordinate buses.
  46
  47   param[out] RootBus           The PCI_ROOT_BRIDGE structure (allocated by the
  48                                caller) that should be filled in by this
  49                                function.
  50
  51   @retval EFI_SUCCESS           Initialization successful. A device path
  52                                 consisting of an ACPI device path node, with
  53                                 UID = RootBusNumber, has been allocated and
  54                                 linked into RootBus.
  55
  56   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
  57 **/
  58 STATIC
  59 EFI_STATUS
  60 InitRootBridge (
  61   IN  UINT8           RootBusNumber,
  62   IN  UINT8           MaxSubBusNumber,
  63   OUT PCI_ROOT_BRIDGE *RootBus
  64   )
  65 {
  66   return EFI_OUT_OF_RESOURCES;
  67 }
  68
  69
  70 /**
  71   Uninitialize a PCI_ROOT_BRIDGE structure set up with InitRootBridge().
  72
  73   param[in] RootBus  The PCI_ROOT_BRIDGE structure, allocated by the caller and
  74                      initialized with InitRootBridge(), that should be
  75                      uninitialized. This function doesn't free RootBus.
  76 **/
  77 STATIC
  78 VOID
  79 UninitRootBridge (
  80   IN PCI_ROOT_BRIDGE *RootBus
  81   )
  82 {
  83 }
  84
  85
  86 /**
  87   Return all the root bridge instances in an array.
  88
  89   @param Count  Return the count of root bridge instances.
  90
  91   @return All the root bridge instances in an array.
  92           The array should be passed into PciHostBridgeFreeRootBridges()
  93           when it's not used.
  94 **/
  95 PCI_ROOT_BRIDGE *
  96 EFIAPI
  97 PciHostBridgeGetRootBridges (
  98   UINTN *Count
  99   )
 100 {
 101   EFI_STATUS           Status;
 102   FIRMWARE_CONFIG_ITEM FwCfgItem;
 103   UINTN                FwCfgSize;
 104   UINT64               ExtraRootBridges;
 105   PCI_ROOT_BRIDGE      *Bridges;
 106   UINTN                Initialized;
 107   UINTN                LastRootBridgeNumber;
 108   UINTN                RootBridgeNumber;
 109
 110   *Count = 0;
 111
 112   //
 113   // QEMU provides the number of extra root buses, shortening the exhaustive
 114   // search below. If there is no hint, the feature is missing.
 115   //
 116   Status = QemuFwCfgFindFile ("etc/extra-pci-roots", &FwCfgItem, &FwCfgSize);
 117   if (EFI_ERROR (Status) || FwCfgSize != sizeof ExtraRootBridges) {
 118     ExtraRootBridges = 0;
 119   } else {
 120     QemuFwCfgSelectItem (FwCfgItem);
 121     QemuFwCfgReadBytes (FwCfgSize, &ExtraRootBridges);
 122
 123     if (ExtraRootBridges > PCI_MAX_BUS) {
 124       DEBUG ((EFI_D_ERROR, "%a: invalid count of extra root buses (%Lu) "
 125         "reported by QEMU\n", __FUNCTION__, ExtraRootBridges));
 126       return NULL;
 127     }
 128     DEBUG ((EFI_D_INFO, "%a: %Lu extra root buses reported by QEMU\n",
 129       __FUNCTION__, ExtraRootBridges));
 130   }
 131
 132   //
 133   // Allocate the "main" root bridge, and any extra root bridges.
 134   //
 135   Bridges = AllocatePool ((1 + (UINTN)ExtraRootBridges) * sizeof *Bridges);
 136   if (Bridges == NULL) {
 137     DEBUG ((EFI_D_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
 138     return NULL;
 139   }
 140   Initialized = 0;
 141
 142   //
 143   // The "main" root bus is always there.
 144   //
 145   LastRootBridgeNumber = 0;
 146
 147   //
 148   // Scan all other root buses. If function 0 of any device on a bus returns a
 149   // VendorId register value different from all-bits-one, then that bus is
 150   // alive.
 151   //
 152   for (RootBridgeNumber = 1;
 153        RootBridgeNumber <= PCI_MAX_BUS && Initialized < ExtraRootBridges;
 154        ++RootBridgeNumber) {
 155     UINTN Device;
 156
 157     for (Device = 0; Device <= PCI_MAX_DEVICE; ++Device) {
 158       if (PciRead16 (PCI_LIB_ADDRESS (RootBridgeNumber, Device, 0,
 159                        PCI_VENDOR_ID_OFFSET)) != MAX_UINT16) {
 160         break;
 161       }
 162     }
 163     if (Device <= PCI_MAX_DEVICE) {
 164       //
 165       // Found the next root bus. We can now install the *previous* one,
 166       // because now we know how big a bus number range *that* one has, for any
 167       // subordinate buses that might exist behind PCI bridges hanging off it.
 168       //
 169       Status = InitRootBridge ((UINT8)LastRootBridgeNumber,
 170                  (UINT8)(RootBridgeNumber - 1), &Bridges[Initialized]);
 171       if (EFI_ERROR (Status)) {
 172         goto FreeBridges;
 173       }
 174       ++Initialized;
 175       LastRootBridgeNumber = RootBridgeNumber;
 176     }
 177   }
 178
 179   //
 180   // Install the last root bus (which might be the only, ie. main, root bus, if
 181   // we've found no extra root buses).
 182   //
 183   Status = InitRootBridge ((UINT8)LastRootBridgeNumber, PCI_MAX_BUS,
 184              &Bridges[Initialized]);
 185   if (EFI_ERROR (Status)) {
 186     goto FreeBridges;
 187   }
 188   ++Initialized;
 189
 190   *Count = Initialized;
 191   return Bridges;
 192
 193 FreeBridges:
 194   while (Initialized > 0) {
 195     --Initialized;
 196     UninitRootBridge (&Bridges[Initialized]);
 197   }
 198
 199   FreePool (Bridges);
 200   return NULL;
 201 }
 202
 203
 204 /**
 205   Free the root bridge instances array returned from
 206   PciHostBridgeGetRootBridges().
 207
 208   @param  The root bridge instances array.
 209   @param  The count of the array.
 210 **/
 211 VOID
 212 EFIAPI
 213 PciHostBridgeFreeRootBridges (
 214   PCI_ROOT_BRIDGE *Bridges,
 215   UINTN           Count
 216   )
 217 {
 218   return;
 219 }
 220
 221
 222 /**
 223   Inform the platform that the resource conflict happens.
 224
 225   @param HostBridgeHandle Handle of the Host Bridge.
 226   @param Configuration    Pointer to PCI I/O and PCI memory resource
 227                           descriptors. The Configuration contains the resources
 228                           for all the root bridges. The resource for each root
 229                           bridge is terminated with END descriptor and an
 230                           additional END is appended indicating the end of the
 231                           entire resources. The resource descriptor field
 232                           values follow the description in
 233                           EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL
 234                           .SubmitResources().
 235 **/
 236 VOID
 237 EFIAPI
 238 PciHostBridgeResourceConflict (
 239   EFI_HANDLE                        HostBridgeHandle,
 240   VOID                              *Configuration
 241   )
 242 {
 243   EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Descriptor;
 244   UINTN                             RootBridgeIndex;
 245   DEBUG ((EFI_D_ERROR, "PciHostBridge: Resource conflict happens!\n"));
 246
 247   RootBridgeIndex = 0;
 248   Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *) Configuration;
 249   while (Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {
 250     DEBUG ((EFI_D_ERROR, "RootBridge[%d]:\n", RootBridgeIndex++));
 251     for (; Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR; Descriptor++) {
 252       ASSERT (Descriptor->ResType <
 253               (sizeof (mPciHostBridgeLibAcpiAddressSpaceTypeStr) /
 254                sizeof (mPciHostBridgeLibAcpiAddressSpaceTypeStr[0])
 255                )
 256               );
 257       DEBUG ((EFI_D_ERROR, " %s: Length/Alignment = 0x%lx / 0x%lx\n",
 258               mPciHostBridgeLibAcpiAddressSpaceTypeStr[Descriptor->ResType],
 259               Descriptor->AddrLen, Descriptor->AddrRangeMax
 260               ));
 261       if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {
 262         DEBUG ((EFI_D_ERROR, "     Granularity/SpecificFlag = %ld / %02x%s\n",
 263                 Descriptor->AddrSpaceGranularity, Descriptor->SpecificFlag,
 264                 ((Descriptor->SpecificFlag &
 265                   EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE
 266                   ) != 0) ? L" (Prefetchable)" : L""
 267                 ));
 268       }
 269     }
 270     //
 271     // Skip the END descriptor for root bridge
 272     //
 273     ASSERT (Descriptor->Desc == ACPI_END_TAG_DESCRIPTOR);
 274     Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)(
 275                    (EFI_ACPI_END_TAG_DESCRIPTOR *)Descriptor + 1
 276                    );
 277   }
 278 }