1 files changed, 83 insertions, 0 deletions
diff --git a/OvmfPkg/Include/Library/FdtSerialPortAddressLib.h b/OvmfPkg/Include/Library/FdtSerialPortAddressLib.h
new file mode 100644
index 0000000000..3d4c911f58
--- /dev/null
+++ b/OvmfPkg/Include/Library/FdtSerialPortAddressLib.h
@@ -0,0 +1,83 @@
+/** @file
+  Determine the base addresses of serial ports from the Device Tree.
+
+  Copyright (C) Red Hat
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef FDT_SERIAL_PORT_ADDRESS_LIB_H_
+#define FDT_SERIAL_PORT_ADDRESS_LIB_H_
+
+#include <Base.h>
+
+typedef struct {
+  UINTN     NumberOfPorts;
+  UINT64    BaseAddress[2];
+} FDT_SERIAL_PORTS;
+
+/**
+  Collect the first ARRAY_SIZE (Ports->BaseAddress) serial ports into Ports from
+  DeviceTree.
+
+  @param[in] DeviceTree  The flat device tree (FDT) to scan.
+
+  @param[in] Compatible  Look for Compatible in the "compatible" property of the
+                         scanned nodes.
+
+  @param[out] Ports      On successful return, Ports->NumberOfPorts contains the
+                         number of serial ports found; it is (a) positive and
+                         (b) at most ARRAY_SIZE (Ports->BaseAddress). If the FDT
+                         had more serial ports, those are not reported. On
+                         error, the contents of Ports are indeterminate.
+
+  @retval RETURN_INVALID_PARAMETER  DeviceTree does not point to a valid FDT
+                                    header.
+
+  @retval RETURN_NOT_FOUND          No compatible and enabled serial port has
+                                    been found.
+
+  @retval RETURN_SUCCESS            At least one compatible and enabled serial
+                                    port has been found; Ports has been filled
+                                    in.
+**/
+RETURN_STATUS
+EFIAPI
+FdtSerialGetPorts (
+  IN  CONST VOID        *DeviceTree,
+  IN  CONST CHAR8       *Compatible,
+  OUT FDT_SERIAL_PORTS  *Ports
+  );
+
+/**
+  Fetch the base address of the serial port identified in the "stdout-path"
+  property of the "/chosen" node in DeviceTree.
+
+  @param[in] DeviceTree    The flat device tree (FDT) to scan.
+
+  @param[out] BaseAddress  On success, the base address of the preferred serial
+                           port (to be used as console). On error, BaseAddress
+                           is not modified.
+
+  @retval RETURN_INVALID_PARAMETER  DeviceTree does not point to a valid FDT
+                                    header.
+
+  @retval RETURN_NOT_FOUND          No enabled console port has been found.
+
+  @retval RETURN_PROTOCOL_ERROR     The first (or only) node path in the
+                                    "stdout-path" property is an empty string.
+
+  @retval RETURN_PROTOCOL_ERROR     The console port has been found in the FDT,
+                                    but its base address is not correctly
+                                    represented.
+
+  @retval RETURN_SUCCESS            BaseAddress has been populated.
+**/
+RETURN_STATUS
+EFIAPI
+FdtSerialGetConsolePort (
+  IN  CONST VOID  *DeviceTree,
+  OUT UINT64      *BaseAddress
+  );
+
+#endif