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   An ORDERED_COLLECTION_USER_COMPARE function that compares root bridge
  37   protocol device paths based on UID.
  38
  39   @param[in] UserStruct1  Pointer to the first ACPI_HID_DEVICE_PATH.
  40
  41   @param[in] UserStruct2  Pointer to the second ACPI_HID_DEVICE_PATH.
  42
  43   @retval <0  If UserStruct1 compares less than UserStruct2.
  44
  45   @retval  0  If UserStruct1 compares equal to UserStruct2.
  46
  47   @retval >0  If UserStruct1 compares greater than UserStruct2.
  48 **/
  49 STATIC
  50 INTN
  51 EFIAPI
  52 RootBridgePathCompare (
  53   IN CONST VOID  *UserStruct1,
  54   IN CONST VOID  *UserStruct2
  55   )
  56 {
  57   CONST ACPI_HID_DEVICE_PATH  *Acpi1;
  58   CONST ACPI_HID_DEVICE_PATH  *Acpi2;
  59
  60   Acpi1 = UserStruct1;
  61   Acpi2 = UserStruct2;
  62
  63   return Acpi1->UID < Acpi2->UID ? -1 :
  64          Acpi1->UID > Acpi2->UID ?  1 :
  65          0;
  66 }
  67
  68 /**
  69   An ORDERED_COLLECTION_KEY_COMPARE function that compares a root bridge
  70   protocol device path against a UID.
  71
  72   @param[in] StandaloneKey  Pointer to the bare UINT32 UID.
  73
  74   @param[in] UserStruct     Pointer to the ACPI_HID_DEVICE_PATH with the
  75                             embedded UINT32 UID.
  76
  77   @retval <0  If StandaloneKey compares less than UserStruct's key.
  78
  79   @retval  0  If StandaloneKey compares equal to UserStruct's key.
  80
  81   @retval >0  If StandaloneKey compares greater than UserStruct's key.
  82 **/
  83 STATIC
  84 INTN
  85 EFIAPI
  86 RootBridgePathKeyCompare (
  87   IN CONST VOID  *StandaloneKey,
  88   IN CONST VOID  *UserStruct
  89   )
  90 {
  91   CONST UINT32                *Uid;
  92   CONST ACPI_HID_DEVICE_PATH  *Acpi;
  93
  94   Uid  = StandaloneKey;
  95   Acpi = UserStruct;
  96
  97   return *Uid < Acpi->UID ? -1 :
  98          *Uid > Acpi->UID ?  1 :
  99          0;
 100 }
 101
 102 /**
 103   Create a structure that maps the relative positions of PCI root buses to bus
 104   numbers.
 105
 106   In the "bootorder" fw_cfg file, QEMU refers to extra PCI root buses by their
 107   positions, in relative root bus number order, not by their actual PCI bus
 108   numbers. The ACPI HID device path nodes however that are associated with
 109   PciRootBridgeIo protocol instances in the system have their UID fields set to
 110   the bus numbers. Create a map that gives, for each extra PCI root bus's
 111   position (ie. "serial number") its actual PCI bus number.
 112
 113   @param[out] ExtraRootBusMap  The data structure implementing the map.
 114
 115   @retval EFI_SUCCESS           ExtraRootBusMap has been populated.
 116
 117   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
 118
 119   @retval EFI_ALREADY_STARTED   A duplicate root bus number has been found in
 120                                 the system. (This should never happen.)
 121
 122   @return                       Error codes returned by
 123                                 gBS->LocateHandleBuffer() and
 124                                 gBS->HandleProtocol().
 125
 126 **/
 127 EFI_STATUS
 128 CreateExtraRootBusMap (
 129   OUT EXTRA_ROOT_BUS_MAP  **ExtraRootBusMap
 130   )
 131 {
 132   EFI_STATUS                Status;
 133   UINTN                     NumHandles;
 134   EFI_HANDLE                *Handles;
 135   ORDERED_COLLECTION        *Collection;
 136   EXTRA_ROOT_BUS_MAP        *Map;
 137   UINTN                     Idx;
 138   ORDERED_COLLECTION_ENTRY  *Entry, *Entry2;
 139
 140   //
 141   // Handles and Collection are temporary / helper variables, while in Map we
 142   // build the return value.
 143   //
 144
 145   Status = gBS->LocateHandleBuffer (
 146                   ByProtocol,
 147                   &gEfiPciRootBridgeIoProtocolGuid,
 148                   NULL /* SearchKey */,
 149                   &NumHandles,
 150                   &Handles
 151                   );
 152   if (EFI_ERROR (Status)) {
 153     return Status;
 154   }
 155
 156   Collection = OrderedCollectionInit (
 157                  RootBridgePathCompare,
 158                  RootBridgePathKeyCompare
 159                  );
 160   if (Collection == NULL) {
 161     Status = EFI_OUT_OF_RESOURCES;
 162     goto FreeHandles;
 163   }
 164
 165   Map = AllocateZeroPool (sizeof *Map);
 166   if (Map == NULL) {
 167     Status = EFI_OUT_OF_RESOURCES;
 168     goto FreeCollection;
 169   }
 170
 171   //
 172   // Collect the ACPI device path protocols of the root bridges.
 173   //
 174   for (Idx = 0; Idx < NumHandles; ++Idx) {
 175     EFI_DEVICE_PATH_PROTOCOL  *DevicePath;
 176
 177     Status = gBS->HandleProtocol (
 178                     Handles[Idx],
 179                     &gEfiDevicePathProtocolGuid,
 180                     (VOID **)&DevicePath
 181                     );
 182     if (EFI_ERROR (Status)) {
 183       goto FreeMap;
 184     }
 185
 186     //
 187     // Examine if the device path is an ACPI HID one, and if so, if UID is
 188     // nonzero (ie. the root bridge that the bus number belongs to is "extra",
 189     // not the main one). In that case, link the device path into Collection.
 190     //
 191     if ((DevicePathType (DevicePath) == ACPI_DEVICE_PATH) &&
 192         (DevicePathSubType (DevicePath) == ACPI_DP) &&
 193         (((ACPI_HID_DEVICE_PATH *)DevicePath)->HID == EISA_PNP_ID (0x0A03)) &&
 194         (((ACPI_HID_DEVICE_PATH *)DevicePath)->UID > 0))
 195     {
 196       Status = OrderedCollectionInsert (Collection, NULL, DevicePath);
 197       if (EFI_ERROR (Status)) {
 198         goto FreeMap;
 199       }
 200
 201       ++Map->Count;
 202     }
 203   }
 204
 205   if (Map->Count > 0) {
 206     //
 207     // At least one extra PCI root bus exists.
 208     //
 209     Map->BusNumbers = AllocatePool (Map->Count * sizeof *Map->BusNumbers);
 210     if (Map->BusNumbers == NULL) {
 211       Status = EFI_OUT_OF_RESOURCES;
 212       goto FreeMap;
 213     }
 214   }
 215
 216   //
 217   // Now collect the bus numbers of the extra PCI root buses into Map.
 218   //
 219   Idx   = 0;
 220   Entry = OrderedCollectionMin (Collection);
 221   while (Idx < Map->Count) {
 222     ACPI_HID_DEVICE_PATH  *Acpi;
 223
 224     ASSERT (Entry != NULL);
 225     Acpi                 = OrderedCollectionUserStruct (Entry);
 226     Map->BusNumbers[Idx] = Acpi->UID;
 227     DEBUG ((
 228       DEBUG_VERBOSE,
 229       "%a: extra bus position 0x%Lx maps to bus number (UID) 0x%x\n",
 230       __FUNCTION__,
 231       (UINT64)(Idx + 1),
 232       Acpi->UID
 233       ));
 234     ++Idx;
 235     Entry = OrderedCollectionNext (Entry);
 236   }
 237
 238   ASSERT (Entry == NULL);
 239
 240   *ExtraRootBusMap = Map;
 241   Status           = EFI_SUCCESS;
 242
 243   //
 244   // Fall through in order to release temporaries.
 245   //
 246
 247 FreeMap:
 248   if (EFI_ERROR (Status)) {
 249     if (Map->BusNumbers != NULL) {
 250       FreePool (Map->BusNumbers);
 251     }
 252
 253     FreePool (Map);
 254   }
 255
 256 FreeCollection:
 257   for (Entry = OrderedCollectionMin (Collection); Entry != NULL;
 258        Entry = Entry2)
 259   {
 260     Entry2 = OrderedCollectionNext (Entry);
 261     OrderedCollectionDelete (Collection, Entry, NULL);
 262   }
 263
 264   OrderedCollectionUninit (Collection);
 265
 266 FreeHandles:
 267   FreePool (Handles);
 268
 269   return Status;
 270 }
 271
 272 /**
 273   Release a map created with CreateExtraRootBusMap().
 274
 275   @param[in] ExtraRootBusMap  The map to release.
 276 */
 277 VOID
 278 DestroyExtraRootBusMap (
 279   IN EXTRA_ROOT_BUS_MAP  *ExtraRootBusMap
 280   )
 281 {
 282   if (ExtraRootBusMap->BusNumbers != NULL) {
 283     FreePool (ExtraRootBusMap->BusNumbers);
 284   }
 285
 286   FreePool (ExtraRootBusMap);
 287 }
 288
 289 /**
 290   Map the position (serial number) of an extra PCI root bus to its bus number.
 291
 292   @param[in]  ExtraRootBusMap  The map created with CreateExtraRootBusMap();
 293
 294   @param[in]  RootBusPos       The extra PCI root bus position to map.
 295
 296   @param[out] RootBusNr        The bus number belonging to the extra PCI root
 297                                bus identified by RootBusPos.
 298
 299   @retval EFI_INVALID_PARAMETER  RootBusPos is zero. The zero position
 300                                  identifies the main root bus, whose bus number
 301                                  is always zero, and is therefore never
 302                                  maintained in ExtraRootBusMap.
 303
 304   @retval EFI_NOT_FOUND          RootBusPos is not found in ExtraRootBusMap.
 305
 306   @retval EFI_SUCCESS            Mapping successful.
 307 **/
 308 EFI_STATUS
 309 MapRootBusPosToBusNr (
 310   IN  CONST EXTRA_ROOT_BUS_MAP  *ExtraRootBusMap,
 311   IN  UINT64                    RootBusPos,
 312   OUT UINT32                    *RootBusNr
 313   )
 314 {
 315   if (RootBusPos == 0) {
 316     return EFI_INVALID_PARAMETER;
 317   }
 318
 319   if (RootBusPos > ExtraRootBusMap->Count) {
 320     return EFI_NOT_FOUND;
 321   }
 322
 323   *RootBusNr = ExtraRootBusMap->BusNumbers[(UINTN)RootBusPos - 1];
 324   return EFI_SUCCESS;
 325 }