diff options
Diffstat (limited to 'OvmfPkg/VirtMmCommunicationDxe/QemuFdt.c')
| -rw-r--r-- | OvmfPkg/VirtMmCommunicationDxe/QemuFdt.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/OvmfPkg/VirtMmCommunicationDxe/QemuFdt.c b/OvmfPkg/VirtMmCommunicationDxe/QemuFdt.c new file mode 100644 index 0000000..bb86290 --- /dev/null +++ b/OvmfPkg/VirtMmCommunicationDxe/QemuFdt.c @@ -0,0 +1,186 @@ +/** @file
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <IndustryStandard/QemuUefiVars.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/DxeServicesTableLib.h>
+#include <Library/IoLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+
+#include <Protocol/FdtClient.h>
+
+#include "VirtMmCommunication.h"
+
+/*
+ Qemu hooks up the uefi vars communication device like this:
+
+ platform-bus@c000000 {
+ interrupt-parent = <0x8002>;
+ ranges = <0x00 0x00 0xc000000 0x2000000>;
+ #address-cells = <0x01>;
+ #size-cells = <0x01>;
+ compatible = "qemu,platform", "simple-bus";
+
+ qemu-uefi-vars@0 {
+ reg = <0x00 0x10>;
+ compatible = "qemu,uefi-vars";
+ };
+ };
+
+ So we have to lookup both platform bus and our device to figure where it
+ actually is mapped in mmio space.
+
+ The code assumes the uefi-vars device is connected to the platform bus without
+ checking that this is actually the case due to FdtClientDxe API limitations.
+*/
+STATIC
+UINT64
+VirtMmGetValue (
+ CONST VOID *Data,
+ UINT32 Size,
+ UINT32 *Pos,
+ UINT32 Cells
+ )
+{
+ UINT32 *Ptr32;
+ UINT64 *Ptr64;
+ UINT64 Value;
+
+ switch (Cells) {
+ case 1:
+ ASSERT (*Pos + 4 <= Size);
+ Ptr32 = (UINT32 *)(Data + *Pos);
+ *Pos += 4;
+ Value = SwapBytes32 (*Ptr32);
+ break;
+ case 2:
+ ASSERT (*Pos + 8 <= Size);
+ Ptr64 = (UINT64 *)(Data + *Pos);
+ *Pos += 8;
+ Value = SwapBytes64 (ReadUnaligned64 (Ptr64));
+ break;
+ default:
+ ASSERT (!"unsupported cell size");
+ Value = 0;
+ }
+
+ return Value;
+}
+
+STATIC
+EFI_STATUS
+EFIAPI
+VirtMmGetProp (
+ IN FDT_CLIENT_PROTOCOL *FdtClient,
+ IN CHAR8 *Compatible,
+ IN CHAR8 *Property,
+ OUT CONST VOID **Values,
+ OUT UINT32 *ValSize
+ )
+{
+ EFI_STATUS Status;
+
+ Status = FdtClient->FindCompatibleNodeProperty (
+ FdtClient,
+ Compatible,
+ Property,
+ Values,
+ ValSize
+ );
+ if (EFI_ERROR (Status)) {
+ DEBUG ((
+ DEBUG_ERROR,
+ "%a: node compatible=\"%a/%a\" not found (%r)\n",
+ __func__,
+ Compatible,
+ Property,
+ Status
+ ));
+ return EFI_NOT_FOUND;
+ }
+
+ DEBUG ((DEBUG_VERBOSE, "%a: %a/%a: ok\n", __func__, Compatible, Property));
+ return EFI_SUCCESS;
+}
+
+EFI_STATUS
+EFIAPI
+VirtMmHwFind (
+ VOID
+ )
+{
+ FDT_CLIENT_PROTOCOL *FdtClient;
+ EFI_STATUS Status;
+ UINT32 Pos;
+ CONST VOID *Ranges;
+ UINT32 RangesSize;
+ CONST VOID *Reg;
+ UINT32 RegSize;
+
+ UINT64 DevAddr;
+ UINT64 DevSize;
+ UINT64 BusChildAddr;
+ UINT64 BusParentAddr;
+ UINT64 BusSize;
+
+ Status = gBS->LocateProtocol (
+ &gFdtClientProtocolGuid,
+ NULL,
+ (VOID **)&FdtClient
+ );
+ ASSERT_EFI_ERROR (Status);
+
+ VirtMmGetProp (
+ FdtClient,
+ "qemu,platform",
+ "ranges",
+ &Ranges,
+ &RangesSize
+ );
+ if (EFI_ERROR (Status)) {
+ return EFI_NOT_FOUND;
+ }
+
+ VirtMmGetProp (
+ FdtClient,
+ UEFI_VARS_FDT_COMPAT,
+ "reg",
+ &Reg,
+ &RegSize
+ );
+ if (EFI_ERROR (Status)) {
+ return EFI_NOT_FOUND;
+ }
+
+ if (RegSize == 2 * sizeof (UINT32)) {
+ ASSERT (RangesSize == RegSize + sizeof (UINT64));
+ Pos = 0;
+ BusChildAddr = VirtMmGetValue (Ranges, RangesSize, &Pos, 1);
+ BusParentAddr = VirtMmGetValue (Ranges, RangesSize, &Pos, 2);
+ BusSize = VirtMmGetValue (Ranges, RangesSize, &Pos, 1);
+ Pos = 0;
+ DevAddr = VirtMmGetValue (Reg, RegSize, &Pos, 1);
+ DevSize = VirtMmGetValue (Reg, RegSize, &Pos, 1);
+ } else {
+ DEBUG ((DEBUG_ERROR, "%a: unexpected regsize\n", __func__));
+ return RETURN_UNSUPPORTED;
+ }
+
+ DEBUG ((DEBUG_VERBOSE, "%a: %a\n", __func__, "qemu,platform"));
+ DEBUG ((DEBUG_VERBOSE, "%a: bus child %8lx\n", __func__, BusChildAddr));
+ DEBUG ((DEBUG_VERBOSE, "%a: bus parent %8lx\n", __func__, BusParentAddr));
+ DEBUG ((DEBUG_VERBOSE, "%a: bus size %8lx\n", __func__, BusSize));
+ DEBUG ((DEBUG_VERBOSE, "%a: %a\n", __func__, UEFI_VARS_FDT_COMPAT));
+ DEBUG ((DEBUG_VERBOSE, "%a: dev addr %8lx\n", __func__, DevAddr));
+ DEBUG ((DEBUG_VERBOSE, "%a: dev size %8lx\n", __func__, DevSize));
+
+ mUefiVarsAddr = DevAddr - BusChildAddr + BusParentAddr;
+ DEBUG ((DEBUG_VERBOSE, "%a: -> mmio at %8lx\n", __func__, mUefiVarsAddr));
+ return RETURN_SUCCESS;
+}
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