OvmfPkg/OvmfPkg.dec: Add 8259-related PCDs in OVMF DEC file

[mirror_edk2.git] / OvmfPkg / OvmfPkg.dec

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index d59508db5633a343b39e18266506606cabbb5f82..cc2a4909afd4a874a8dd954d94dac177ea84c8c8 100644 (file)
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -122,6 +122,32 @@
   gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize|0x0|UINT32|0x1a\r
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDecompressionScratchEnd|0x0|UINT32|0x1f\r
 \r
+  ## Pcd8259LegacyModeMask defines the default mask value for platform. This\r
+  #  value is determined.\r
+  #  1) If platform only support pure UEFI, value should be set to 0xFFFF or\r
+  #     0xFFFE; Because only clock interrupt is allowed in legacy mode in pure\r
+  #     UEFI platform.\r
+  #  2) If platform install CSM and use thunk module:\r
+  #     a) If thunk call provided by CSM binary requires some legacy interrupt\r
+  #        support, the corresponding bit should be opened as 0.\r
+  #        For example, if keyboard interfaces provided CSM binary use legacy\r
+  #        keyboard interrupt in 8259 bit 1, then the value should be set to\r
+  #        0xFFFC.\r
+  #     b) If all thunk call provied by CSM binary do not require legacy\r
+  #        interrupt support, value should be set to 0xFFFF or 0xFFFE.\r
+  #\r
+  #  The default value of legacy mode mask could be changed by\r
+  #  EFI_LEGACY_8259_PROTOCOL->SetMask(). But it is rarely need change it\r
+  #  except some special cases such as when initializing the CSM binary, it\r
+  #  should be set to 0xFFFF to mask all legacy interrupt. Please restore the\r
+  #  original legacy mask value if changing is made for these special case.\r
+  gUefiOvmfPkgTokenSpaceGuid.Pcd8259LegacyModeMask|0xFFFF|UINT16|0x3\r
+\r
+  ## Pcd8259LegacyModeEdgeLevel defines the default edge level for legacy\r
+  #  mode's interrrupt controller.\r
+  #  For the corresponding bits, 0 = Edge triggered and 1 = Level triggered.\r
+  gUefiOvmfPkgTokenSpaceGuid.Pcd8259LegacyModeEdgeLevel|0x0000|UINT16|0x5\r
+\r
 [PcdsDynamic, PcdsDynamicEx]\r
   gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent|0|UINT64|2\r
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashVariablesEnable|FALSE|BOOLEAN|0x10\r