ArmVirtPkg: store separate console and debug PL011 addresses in GUID HOB

PlatformPeiLib produces the EarlyPL011BaseAddress GUID HOB, and
FdtPL011SerialPortLib consumes it. Extend the HOB such that it also carry
the base address of the PL011 UART meant for DebugLib usage -- namely the
first UART that is *not* designated by the /chosen node's "stdout-path"
property. Implement this policy in PlatformPeiLib.

Note that as far as the SerialPortLib+console UART is concerned, this
patch makes no difference. That selection remains consistent with the
pre-patch state, and therefore consistent with EarlyFdtPL011SerialPortLib.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20231008153912.175941-6-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4577
[lersek@redhat.com: add TianoCore BZ reference]

ArmVirtPkg/Include/Guid/EarlyPL011BaseAddress.h

@@ -1,6 +1,6 @@
 /** @file
-  GUID for the HOB that caches the base address of the PL011 serial port, for
+  GUID for the HOB that caches the base address(es) of the PL011 serial port(s),
-  when PCD access is not available.
+  for when PCD access is not available.
 
   Copyright (C) 2014, Red Hat, Inc.
 
@@ -18,4 +18,15 @@
 
 extern EFI_GUID  gEarlyPL011BaseAddressGuid;
 
+typedef struct {
+  //
+  // for SerialPortLib and console IO
+  //
+  UINT64    ConsoleAddress;
+  //
+  // for DebugLib; may equal ConsoleAddress if there's only one PL011 UART
+  //
+  UINT64    DebugAddress;
+} EARLY_PL011_BASE_ADDRESS;
+
 #endif

ArmVirtPkg/Library/FdtPL011SerialPortLib/FdtPL011SerialPortLib.c

@@ -46,7 +46,7 @@ SerialPortInitialize (
 {
   VOID                            *Hob;
   RETURN_STATUS                   Status;
-  CONST UINT64                    *UartBase;
+  CONST EARLY_PL011_BASE_ADDRESS  *UartBase;
   UINTN                           SerialBaseAddress;
   UINT64                          BaudRate;
   UINT32                          ReceiveFifoDepth;
@@ -70,7 +70,7 @@ SerialPortInitialize (
 
   UartBase = GET_GUID_HOB_DATA (Hob);
 
-  SerialBaseAddress = (UINTN)*UartBase;
+  SerialBaseAddress = (UINTN)UartBase->ConsoleAddress;
   if (SerialBaseAddress == 0) {
     Status = RETURN_NOT_FOUND;
     goto Failed;

ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c

@@ -9,6 +9,7 @@
 
 #include <PiPei.h>
 
+#include <Library/BaseMemoryLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/DebugLib.h>
 #include <Library/HobLib.h>
@@ -43,7 +44,7 @@ PlatformPeim (
   UINTN                     FdtSize;
   UINTN                     FdtPages;
   UINT64                    *FdtHobData;
-  UINT64                    *UartHobData;
+  EARLY_PL011_BASE_ADDRESS  *UartHobData;
   FDT_SERIAL_PORTS          Ports;
   INT32                     Node, Prev;
   INT32                     Parent, Depth;
@@ -72,24 +73,55 @@ PlatformPeim (
 
   UartHobData = BuildGuidHob (&gEarlyPL011BaseAddressGuid, sizeof *UartHobData);
   ASSERT (UartHobData != NULL);
-  *UartHobData = 0;
+  SetMem (UartHobData, sizeof *UartHobData, 0);
 
   Status = FdtSerialGetPorts (Base, "arm,pl011", &Ports);
   if (!EFI_ERROR (Status)) {
-    UINT64  UartBase;
+    if (Ports.NumberOfPorts == 1) {
+      //
+      // Just one UART; direct both SerialPortLib+console and DebugLib to it.
+      //
+      UartHobData->ConsoleAddress = Ports.BaseAddress[0];
+      UartHobData->DebugAddress   = Ports.BaseAddress[0];
+    } else {
+      UINT64  ConsoleAddress;
 
-    //
+      Status = FdtSerialGetConsolePort (Base, &ConsoleAddress);
-    // Default to the first port found, but (if there are multiple ports) allow
+      if (EFI_ERROR (Status)) {
-    // the "/chosen" node to override it. Note that if FdtSerialGetConsolePort()
+        //
-    // fails, it does not modify UartBase.
+        // At least two UARTs; but failed to get the console preference. Use the
-    //
+        // first UART for SerialPortLib+console, and the second one for
-    UartBase = Ports.BaseAddress[0];
+        // DebugLib.
-    if (Ports.NumberOfPorts > 1) {
+        //
-      FdtSerialGetConsolePort (Base, &UartBase);
+        UartHobData->ConsoleAddress = Ports.BaseAddress[0];
+        UartHobData->DebugAddress   = Ports.BaseAddress[1];
+      } else {
+        //
+        // At least two UARTs; and console preference available. Use the
+        // preferred UART for SerialPortLib+console, and *another* UART for
+        // DebugLib.
+        //
+        UartHobData->ConsoleAddress = ConsoleAddress;
+        if (ConsoleAddress == Ports.BaseAddress[0]) {
+          UartHobData->DebugAddress = Ports.BaseAddress[1];
+        } else {
+          UartHobData->DebugAddress = Ports.BaseAddress[0];
+        }
+      }
     }
 
-    DEBUG ((DEBUG_INFO, "%a: PL011 UART @ 0x%lx\n", __func__, UartBase));
+    DEBUG ((
-    *UartHobData = UartBase;
+      DEBUG_INFO,
+      "%a: PL011 UART (console) @ 0x%lx\n",
+      __func__,
+      UartHobData->ConsoleAddress
+      ));
+    DEBUG ((
+      DEBUG_INFO,
+      "%a: PL011 UART (debug) @ 0x%lx\n",
+      __func__,
+      UartHobData->DebugAddress
+      ));
   }
 
   TpmBase = 0;

ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.inf

@@ -31,6 +31,7 @@
   gArmVirtTokenSpaceGuid.PcdTpm2SupportEnabled
 
 [LibraryClasses]
+  BaseMemoryLib
   DebugLib
   HobLib
   FdtLib