OvmfPkg/Library/QemuBootOrderLib/ExtraRootBusMap.c

   1 /** @file
   2   Map positions of extra PCI root buses to bus numbers.
   3
   4   Copyright (C) 2015, Red Hat, Inc.
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include <Library/DebugLib.h>
  10 #include <Library/DevicePathLib.h>
  11 #include <Library/MemoryAllocationLib.h>
  12 #include <Library/OrderedCollectionLib.h>
  13 #include <Library/UefiBootServicesTableLib.h>
  14 #include <Protocol/DevicePath.h>
  15 #include <Protocol/PciRootBridgeIo.h>
  16
  17 #include "ExtraRootBusMap.h"
  18
  19 //
  20 // The BusNumbers field is an array with Count elements. The elements increase
  21 // strictry monotonically. Zero is not an element (because the zero bus number
  22 // belongs to the "main" root bus, never to an extra root bus). Offset N in the
  23 // array maps the extra root bus with position (N+1) to its bus number (because
  24 // the root bus with position 0 is always the main root bus, therefore we don't
  25 // store it).
  26 //
  27 // If there are no extra root buses in the system, then Count is 0, and
  28 // BusNumbers is NULL.
  29 //
  30 struct EXTRA_ROOT_BUS_MAP_STRUCT {
  31   UINT32 *BusNumbers;
  32   UINTN  Count;
  33 };
  34
  35
  36 /**
  37   An ORDERED_COLLECTION_USER_COMPARE function that compares root bridge
  38   protocol device paths based on UID.
  39
  40   @param[in] UserStruct1  Pointer to the first ACPI_HID_DEVICE_PATH.
  41
  42   @param[in] UserStruct2  Pointer to the second ACPI_HID_DEVICE_PATH.
  43
  44   @retval <0  If UserStruct1 compares less than UserStruct2.
  45
  46   @retval  0  If UserStruct1 compares equal to UserStruct2.
  47
  48   @retval >0  If UserStruct1 compares greater than UserStruct2.
  49 **/
  50 STATIC
  51 INTN
  52 EFIAPI
  53 RootBridgePathCompare (
  54   IN CONST VOID *UserStruct1,
  55   IN CONST VOID *UserStruct2
  56   )
  57 {
  58   CONST ACPI_HID_DEVICE_PATH *Acpi1;
  59   CONST ACPI_HID_DEVICE_PATH *Acpi2;
  60
  61   Acpi1 = UserStruct1;
  62   Acpi2 = UserStruct2;
  63
  64   return Acpi1->UID < Acpi2->UID ? -1 :
  65          Acpi1->UID > Acpi2->UID ?  1 :
  66          0;
  67 }
  68
  69
  70 /**
  71   An ORDERED_COLLECTION_KEY_COMPARE function that compares a root bridge
  72   protocol device path against a UID.
  73
  74   @param[in] StandaloneKey  Pointer to the bare UINT32 UID.
  75
  76   @param[in] UserStruct     Pointer to the ACPI_HID_DEVICE_PATH with the
  77                             embedded UINT32 UID.
  78
  79   @retval <0  If StandaloneKey compares less than UserStruct's key.
  80
  81   @retval  0  If StandaloneKey compares equal to UserStruct's key.
  82
  83   @retval >0  If StandaloneKey compares greater than UserStruct's key.
  84 **/
  85 STATIC
  86 INTN
  87 EFIAPI
  88 RootBridgePathKeyCompare (
  89   IN CONST VOID *StandaloneKey,
  90   IN CONST VOID *UserStruct
  91   )
  92 {
  93   CONST UINT32               *Uid;
  94   CONST ACPI_HID_DEVICE_PATH *Acpi;
  95
  96   Uid  = StandaloneKey;
  97   Acpi = UserStruct;
  98
  99   return *Uid < Acpi->UID ? -1 :
 100          *Uid > Acpi->UID ?  1 :
 101          0;
 102 }
 103
 104
 105 /**
 106   Create a structure that maps the relative positions of PCI root buses to bus
 107   numbers.
 108
 109   In the "bootorder" fw_cfg file, QEMU refers to extra PCI root buses by their
 110   positions, in relative root bus number order, not by their actual PCI bus
 111   numbers. The ACPI HID device path nodes however that are associated with
 112   PciRootBridgeIo protocol instances in the system have their UID fields set to
 113   the bus numbers. Create a map that gives, for each extra PCI root bus's
 114   position (ie. "serial number") its actual PCI bus number.
 115
 116   @param[out] ExtraRootBusMap  The data structure implementing the map.
 117
 118   @retval EFI_SUCCESS           ExtraRootBusMap has been populated.
 119
 120   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
 121
 122   @retval EFI_ALREADY_STARTED   A duplicate root bus number has been found in
 123                                 the system. (This should never happen.)
 124
 125   @return                       Error codes returned by
 126                                 gBS->LocateHandleBuffer() and
 127                                 gBS->HandleProtocol().
 128
 129 **/
 130 EFI_STATUS
 131 CreateExtraRootBusMap (
 132   OUT EXTRA_ROOT_BUS_MAP **ExtraRootBusMap
 133   )
 134 {
 135   EFI_STATUS               Status;
 136   UINTN                    NumHandles;
 137   EFI_HANDLE               *Handles;
 138   ORDERED_COLLECTION       *Collection;
 139   EXTRA_ROOT_BUS_MAP       *Map;
 140   UINTN                    Idx;
 141   ORDERED_COLLECTION_ENTRY *Entry, *Entry2;
 142
 143   //
 144   // Handles and Collection are temporary / helper variables, while in Map we
 145   // build the return value.
 146   //
 147
 148   Status = gBS->LocateHandleBuffer (ByProtocol,
 149                   &gEfiPciRootBridgeIoProtocolGuid, NULL /* SearchKey */,
 150                   &NumHandles, &Handles);
 151   if (EFI_ERROR (Status))  {
 152     return Status;
 153   }
 154
 155   Collection = OrderedCollectionInit (RootBridgePathCompare,
 156                  RootBridgePathKeyCompare);
 157   if (Collection == NULL) {
 158     Status = EFI_OUT_OF_RESOURCES;
 159     goto FreeHandles;
 160   }
 161
 162   Map = AllocateZeroPool (sizeof *Map);
 163   if (Map == NULL) {
 164     Status = EFI_OUT_OF_RESOURCES;
 165     goto FreeCollection;
 166   }
 167
 168   //
 169   // Collect the ACPI device path protocols of the root bridges.
 170   //
 171   for (Idx = 0; Idx < NumHandles; ++Idx) {
 172     EFI_DEVICE_PATH_PROTOCOL *DevicePath;
 173
 174     Status = gBS->HandleProtocol (Handles[Idx], &gEfiDevicePathProtocolGuid,
 175                     (VOID**)&DevicePath);
 176     if (EFI_ERROR (Status)) {
 177       goto FreeMap;
 178     }
 179
 180     //
 181     // Examine if the device path is an ACPI HID one, and if so, if UID is
 182     // nonzero (ie. the root bridge that the bus number belongs to is "extra",
 183     // not the main one). In that case, link the device path into Collection.
 184     //
 185     if (DevicePathType (DevicePath) == ACPI_DEVICE_PATH &&
 186         DevicePathSubType (DevicePath) == ACPI_DP &&
 187         ((ACPI_HID_DEVICE_PATH *)DevicePath)->HID == EISA_PNP_ID(0x0A03) &&
 188         ((ACPI_HID_DEVICE_PATH *)DevicePath)->UID > 0) {
 189       Status = OrderedCollectionInsert (Collection, NULL, DevicePath);
 190       if (EFI_ERROR (Status)) {
 191         goto FreeMap;
 192       }
 193       ++Map->Count;
 194     }
 195   }
 196
 197   if (Map->Count > 0) {
 198     //
 199     // At least one extra PCI root bus exists.
 200     //
 201     Map->BusNumbers = AllocatePool (Map->Count * sizeof *Map->BusNumbers);
 202     if (Map->BusNumbers == NULL) {
 203       Status = EFI_OUT_OF_RESOURCES;
 204       goto FreeMap;
 205     }
 206   }
 207
 208   //
 209   // Now collect the bus numbers of the extra PCI root buses into Map.
 210   //
 211   Idx = 0;
 212   Entry = OrderedCollectionMin (Collection);
 213   while (Idx < Map->Count) {
 214     ACPI_HID_DEVICE_PATH *Acpi;
 215
 216     ASSERT (Entry != NULL);
 217     Acpi = OrderedCollectionUserStruct (Entry);
 218     Map->BusNumbers[Idx] = Acpi->UID;
 219     DEBUG ((DEBUG_VERBOSE,
 220       "%a: extra bus position 0x%Lx maps to bus number (UID) 0x%x\n",
 221       __FUNCTION__, (UINT64)(Idx + 1), Acpi->UID));
 222     ++Idx;
 223     Entry = OrderedCollectionNext (Entry);
 224   }
 225   ASSERT (Entry == NULL);
 226
 227   *ExtraRootBusMap = Map;
 228   Status = EFI_SUCCESS;
 229
 230   //
 231   // Fall through in order to release temporaries.
 232   //
 233
 234 FreeMap:
 235   if (EFI_ERROR (Status)) {
 236     if (Map->BusNumbers != NULL) {
 237       FreePool (Map->BusNumbers);
 238     }
 239     FreePool (Map);
 240   }
 241
 242 FreeCollection:
 243   for (Entry = OrderedCollectionMin (Collection); Entry != NULL;
 244        Entry = Entry2) {
 245     Entry2 = OrderedCollectionNext (Entry);
 246     OrderedCollectionDelete (Collection, Entry, NULL);
 247   }
 248   OrderedCollectionUninit (Collection);
 249
 250 FreeHandles:
 251   FreePool (Handles);
 252
 253   return Status;
 254 }
 255
 256
 257 /**
 258   Release a map created with CreateExtraRootBusMap().
 259
 260   @param[in] ExtraRootBusMap  The map to release.
 261 */
 262 VOID
 263 DestroyExtraRootBusMap (
 264   IN EXTRA_ROOT_BUS_MAP *ExtraRootBusMap
 265   )
 266 {
 267   if (ExtraRootBusMap->BusNumbers != NULL) {
 268     FreePool (ExtraRootBusMap->BusNumbers);
 269   }
 270   FreePool (ExtraRootBusMap);
 271 }
 272
 273 /**
 274   Map the position (serial number) of an extra PCI root bus to its bus number.
 275
 276   @param[in]  ExtraRootBusMap  The map created with CreateExtraRootBusMap();
 277
 278   @param[in]  RootBusPos       The extra PCI root bus position to map.
 279
 280   @param[out] RootBusNr        The bus number belonging to the extra PCI root
 281                                bus identified by RootBusPos.
 282
 283   @retval EFI_INVALID_PARAMETER  RootBusPos is zero. The zero position
 284                                  identifies the main root bus, whose bus number
 285                                  is always zero, and is therefore never
 286                                  maintained in ExtraRootBusMap.
 287
 288   @retval EFI_NOT_FOUND          RootBusPos is not found in ExtraRootBusMap.
 289
 290   @retval EFI_SUCCESS            Mapping successful.
 291 **/
 292 EFI_STATUS
 293 MapRootBusPosToBusNr (
 294   IN  CONST EXTRA_ROOT_BUS_MAP *ExtraRootBusMap,
 295   IN  UINT64                   RootBusPos,
 296   OUT UINT32                   *RootBusNr
 297   )
 298 {
 299   if (RootBusPos == 0) {
 300     return EFI_INVALID_PARAMETER;
 301   }
 302   if (RootBusPos > ExtraRootBusMap->Count) {
 303     return EFI_NOT_FOUND;
 304   }
 305   *RootBusNr = ExtraRootBusMap->BusNumbers[(UINTN)RootBusPos - 1];
 306   return EFI_SUCCESS;
 307 }