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/BaseMemoryLib.h>
  21 #include <Library/DebugLib.h>
  22 #include <Library/MemoryAllocationLib.h>
  23 #include <Library/PciHostBridgeLib.h>
  24 #include <Library/PciLib.h>
  25 #include <Library/QemuFwCfgLib.h>
  26
  27
  28 GLOBAL_REMOVE_IF_UNREFERENCED
  29 CHAR16 *mPciHostBridgeLibAcpiAddressSpaceTypeStr[] = {
  30   L"Mem", L"I/O", L"Bus"
  31 };
  32
  33
  34 /**
  35   Initialize a PCI_ROOT_BRIDGE structure.
  36
  37   param[in]  RootBusNumber     The bus number to store in RootBus.
  38
  39   param[in]  MaxSubBusNumber   The inclusive maximum bus number that can be
  40                                assigned to any subordinate bus found behind any
  41                                PCI bridge hanging off this root bus.
  42
  43                                The caller is repsonsible for ensuring that
  44                                RootBusNumber <= MaxSubBusNumber. If
  45                                RootBusNumber equals MaxSubBusNumber, then the
  46                                root bus has no room for subordinate buses.
  47
  48   param[out] RootBus           The PCI_ROOT_BRIDGE structure (allocated by the
  49                                caller) that should be filled in by this
  50                                function.
  51
  52   @retval EFI_SUCCESS           Initialization successful. A device path
  53                                 consisting of an ACPI device path node, with
  54                                 UID = RootBusNumber, has been allocated and
  55                                 linked into RootBus.
  56
  57   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
  58 **/
  59 STATIC
  60 EFI_STATUS
  61 InitRootBridge (
  62   IN  UINT8           RootBusNumber,
  63   IN  UINT8           MaxSubBusNumber,
  64   OUT PCI_ROOT_BRIDGE *RootBus
  65   )
  66 {
  67   //
  68   // Be safe if other fields are added to PCI_ROOT_BRIDGE later.
  69   //
  70   ZeroMem (RootBus, sizeof *RootBus);
  71
  72   RootBus->Segment = 0;
  73
  74   return EFI_OUT_OF_RESOURCES;
  75 }
  76
  77
  78 /**
  79   Uninitialize a PCI_ROOT_BRIDGE structure set up with InitRootBridge().
  80
  81   param[in] RootBus  The PCI_ROOT_BRIDGE structure, allocated by the caller and
  82                      initialized with InitRootBridge(), that should be
  83                      uninitialized. This function doesn't free RootBus.
  84 **/
  85 STATIC
  86 VOID
  87 UninitRootBridge (
  88   IN PCI_ROOT_BRIDGE *RootBus
  89   )
  90 {
  91 }
  92
  93
  94 /**
  95   Return all the root bridge instances in an array.
  96
  97   @param Count  Return the count of root bridge instances.
  98
  99   @return All the root bridge instances in an array.
 100           The array should be passed into PciHostBridgeFreeRootBridges()
 101           when it's not used.
 102 **/
 103 PCI_ROOT_BRIDGE *
 104 EFIAPI
 105 PciHostBridgeGetRootBridges (
 106   UINTN *Count
 107   )
 108 {
 109   EFI_STATUS           Status;
 110   FIRMWARE_CONFIG_ITEM FwCfgItem;
 111   UINTN                FwCfgSize;
 112   UINT64               ExtraRootBridges;
 113   PCI_ROOT_BRIDGE      *Bridges;
 114   UINTN                Initialized;
 115   UINTN                LastRootBridgeNumber;
 116   UINTN                RootBridgeNumber;
 117
 118   *Count = 0;
 119
 120   //
 121   // QEMU provides the number of extra root buses, shortening the exhaustive
 122   // search below. If there is no hint, the feature is missing.
 123   //
 124   Status = QemuFwCfgFindFile ("etc/extra-pci-roots", &FwCfgItem, &FwCfgSize);
 125   if (EFI_ERROR (Status) || FwCfgSize != sizeof ExtraRootBridges) {
 126     ExtraRootBridges = 0;
 127   } else {
 128     QemuFwCfgSelectItem (FwCfgItem);
 129     QemuFwCfgReadBytes (FwCfgSize, &ExtraRootBridges);
 130
 131     if (ExtraRootBridges > PCI_MAX_BUS) {
 132       DEBUG ((EFI_D_ERROR, "%a: invalid count of extra root buses (%Lu) "
 133         "reported by QEMU\n", __FUNCTION__, ExtraRootBridges));
 134       return NULL;
 135     }
 136     DEBUG ((EFI_D_INFO, "%a: %Lu extra root buses reported by QEMU\n",
 137       __FUNCTION__, ExtraRootBridges));
 138   }
 139
 140   //
 141   // Allocate the "main" root bridge, and any extra root bridges.
 142   //
 143   Bridges = AllocatePool ((1 + (UINTN)ExtraRootBridges) * sizeof *Bridges);
 144   if (Bridges == NULL) {
 145     DEBUG ((EFI_D_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
 146     return NULL;
 147   }
 148   Initialized = 0;
 149
 150   //
 151   // The "main" root bus is always there.
 152   //
 153   LastRootBridgeNumber = 0;
 154
 155   //
 156   // Scan all other root buses. If function 0 of any device on a bus returns a
 157   // VendorId register value different from all-bits-one, then that bus is
 158   // alive.
 159   //
 160   for (RootBridgeNumber = 1;
 161        RootBridgeNumber <= PCI_MAX_BUS && Initialized < ExtraRootBridges;
 162        ++RootBridgeNumber) {
 163     UINTN Device;
 164
 165     for (Device = 0; Device <= PCI_MAX_DEVICE; ++Device) {
 166       if (PciRead16 (PCI_LIB_ADDRESS (RootBridgeNumber, Device, 0,
 167                        PCI_VENDOR_ID_OFFSET)) != MAX_UINT16) {
 168         break;
 169       }
 170     }
 171     if (Device <= PCI_MAX_DEVICE) {
 172       //
 173       // Found the next root bus. We can now install the *previous* one,
 174       // because now we know how big a bus number range *that* one has, for any
 175       // subordinate buses that might exist behind PCI bridges hanging off it.
 176       //
 177       Status = InitRootBridge ((UINT8)LastRootBridgeNumber,
 178                  (UINT8)(RootBridgeNumber - 1), &Bridges[Initialized]);
 179       if (EFI_ERROR (Status)) {
 180         goto FreeBridges;
 181       }
 182       ++Initialized;
 183       LastRootBridgeNumber = RootBridgeNumber;
 184     }
 185   }
 186
 187   //
 188   // Install the last root bus (which might be the only, ie. main, root bus, if
 189   // we've found no extra root buses).
 190   //
 191   Status = InitRootBridge ((UINT8)LastRootBridgeNumber, PCI_MAX_BUS,
 192              &Bridges[Initialized]);
 193   if (EFI_ERROR (Status)) {
 194     goto FreeBridges;
 195   }
 196   ++Initialized;
 197
 198   *Count = Initialized;
 199   return Bridges;
 200
 201 FreeBridges:
 202   while (Initialized > 0) {
 203     --Initialized;
 204     UninitRootBridge (&Bridges[Initialized]);
 205   }
 206
 207   FreePool (Bridges);
 208   return NULL;
 209 }
 210
 211
 212 /**
 213   Free the root bridge instances array returned from
 214   PciHostBridgeGetRootBridges().
 215
 216   @param  The root bridge instances array.
 217   @param  The count of the array.
 218 **/
 219 VOID
 220 EFIAPI
 221 PciHostBridgeFreeRootBridges (
 222   PCI_ROOT_BRIDGE *Bridges,
 223   UINTN           Count
 224   )
 225 {
 226   if (Bridges == NULL && Count == 0) {
 227     return;
 228   }
 229   ASSERT (Bridges != NULL && Count > 0);
 230
 231   do {
 232     --Count;
 233     UninitRootBridge (&Bridges[Count]);
 234   } while (Count > 0);
 235
 236   FreePool (Bridges);
 237 }
 238
 239
 240 /**
 241   Inform the platform that the resource conflict happens.
 242
 243   @param HostBridgeHandle Handle of the Host Bridge.
 244   @param Configuration    Pointer to PCI I/O and PCI memory resource
 245                           descriptors. The Configuration contains the resources
 246                           for all the root bridges. The resource for each root
 247                           bridge is terminated with END descriptor and an
 248                           additional END is appended indicating the end of the
 249                           entire resources. The resource descriptor field
 250                           values follow the description in
 251                           EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL
 252                           .SubmitResources().
 253 **/
 254 VOID
 255 EFIAPI
 256 PciHostBridgeResourceConflict (
 257   EFI_HANDLE                        HostBridgeHandle,
 258   VOID                              *Configuration
 259   )
 260 {
 261   EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *Descriptor;
 262   UINTN                             RootBridgeIndex;
 263   DEBUG ((EFI_D_ERROR, "PciHostBridge: Resource conflict happens!\n"));
 264
 265   RootBridgeIndex = 0;
 266   Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *) Configuration;
 267   while (Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR) {
 268     DEBUG ((EFI_D_ERROR, "RootBridge[%d]:\n", RootBridgeIndex++));
 269     for (; Descriptor->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR; Descriptor++) {
 270       ASSERT (Descriptor->ResType <
 271               (sizeof (mPciHostBridgeLibAcpiAddressSpaceTypeStr) /
 272                sizeof (mPciHostBridgeLibAcpiAddressSpaceTypeStr[0])
 273                )
 274               );
 275       DEBUG ((EFI_D_ERROR, " %s: Length/Alignment = 0x%lx / 0x%lx\n",
 276               mPciHostBridgeLibAcpiAddressSpaceTypeStr[Descriptor->ResType],
 277               Descriptor->AddrLen, Descriptor->AddrRangeMax
 278               ));
 279       if (Descriptor->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM) {
 280         DEBUG ((EFI_D_ERROR, "     Granularity/SpecificFlag = %ld / %02x%s\n",
 281                 Descriptor->AddrSpaceGranularity, Descriptor->SpecificFlag,
 282                 ((Descriptor->SpecificFlag &
 283                   EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE
 284                   ) != 0) ? L" (Prefetchable)" : L""
 285                 ));
 286       }
 287     }
 288     //
 289     // Skip the END descriptor for root bridge
 290     //
 291     ASSERT (Descriptor->Desc == ACPI_END_TAG_DESCRIPTOR);
 292     Descriptor = (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *)(
 293                    (EFI_ACPI_END_TAG_DESCRIPTOR *)Descriptor + 1
 294                    );
 295   }
 296 }