ArmVirtPkg: introduce FdtSerialPortAddressLib

Introduce a new library class + instance for:

- collecting serial port base addresses from the device tree,

- collecting the /chosen stdout-path serial port base address from the
  device tree.

The logic is loosely based on the following functions:

- SerialPortGetBaseAddress()
  [ArmVirtPkg/Library/FdtPL011SerialPortLib/EarlyFdtPL011SerialPortLib.c]

- PlatformPeim() [ArmVirtPkg/Library/PlatformPeiLib/PlatformPeiLib.c]

- GetSerialConsolePortAddress()
  [ArmVirtPkg/Library/Fdt16550SerialPortHookLib/EarlyFdt16550SerialPortHookLib.c]

which are going to be converted to clients of the new library later.
Copyright notices from those other files are preserved.

The new library fixes the following warts, found by reading the existent
code:

- Neither of the three functions check whether the "reg" property exists.
  (This may be implicitly checked when they compare the property size to
  16.)

- GetSerialConsolePortAddress() uses ScanMem8() for locating a colon (":")
  node path separator in "stdout-path", when AsciiStrStr() could work just
  as fine. While ScanMem8() is likely faster, "stdout-path" is presumably
  very short, and ScanMem8() introduces an extra lib class dependency
  (namely BaseMemoryLib).

- If ScanMem8() fails to locate a colon in "stdout-path", then
  GetSerialConsolePortAddress() re-measures the length of the whole
  "stdout-path" property. This is conceptually (if not performance-wise)
  disturbing, because we know the whole size of the "stdout-path" property
  from the property lookup just before, so we only need to subtract the
  NUL-terminator for learning the length.

- GetSerialConsolePortAddress() does not check if the first (or only) node
  path inside the "stdout-path" property is empty. (Not a big deal, the
  subsequent alias resolution should simply fail.)

- GetSerialConsolePortAddress() does not verify if the node path retrieved
  (and potentially alias-resolved) from "stdout-path" can be located in
  the device tree; it assumes it.

- Code is duplicated (of course) between SerialPortGetBaseAddress() and
  PlatformPeim(), but more surprisingly, all three functions embed the
  same code for verifying the "status" property of the serial port node,
  and for checking and reading its "reg" property.

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: <20231008153912.175941-2-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]

5 files changed, 368 insertions, 0 deletions

diff --git a/ArmVirtPkg/ArmVirt.dsc.inc b/ArmVirtPkg/ArmVirt.dsc.inc
index 3f7bac6bf3..0d71155254 100644
--- a/ArmVirtPkg/ArmVirt.dsc.inc
+++ b/ArmVirtPkg/ArmVirt.dsc.inc
@@ -121,6 +121,7 @@
   # ARM PL011 UART Driver

   PL011UartLib|ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf

   SerialPortLib|ArmVirtPkg/Library/FdtPL011SerialPortLib/FdtPL011SerialPortLib.inf

+  FdtSerialPortAddressLib|ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.inf

 

   PeCoffExtraActionLib|ArmPkg/Library/DebugPeCoffExtraActionLib/DebugPeCoffExtraActionLib.inf

   #PeCoffExtraActionLib|MdePkg/Library/BasePeCoffExtraActionLibNull/BasePeCoffExtraActionLibNull.inf

diff --git a/ArmVirtPkg/ArmVirtPkg.dec b/ArmVirtPkg/ArmVirtPkg.dec
index 4645c91a83..0f2d787327 100644
--- a/ArmVirtPkg/ArmVirtPkg.dec
+++ b/ArmVirtPkg/ArmVirtPkg.dec
@@ -27,6 +27,7 @@
 

 [LibraryClasses]

   ArmVirtMemInfoLib|Include/Library/ArmVirtMemInfoLib.h

+  FdtSerialPortAddressLib|Include/Library/FdtSerialPortAddressLib.h

 

 [Guids.common]

   gArmVirtTokenSpaceGuid = { 0x0B6F5CA7, 0x4F53, 0x445A, { 0xB7, 0x6E, 0x2E, 0x36, 0x5B, 0x80, 0x63, 0x66 } }

diff --git a/ArmVirtPkg/Include/Library/FdtSerialPortAddressLib.h b/ArmVirtPkg/Include/Library/FdtSerialPortAddressLib.h
new file mode 100644
index 0000000000..3d4c911f58
--- /dev/null
+++ b/ArmVirtPkg/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

diff --git a/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.c b/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.c
new file mode 100644
index 0000000000..f6508e0989
--- /dev/null
+++ b/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.c
@@ -0,0 +1,256 @@
+/** @file

+  Determine the base addresses of serial ports from the Device Tree.

+

+  Copyright (C) Red Hat

+  Copyright (c) 2011 - 2023, Arm Ltd. All rights reserved.<BR>

+  Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>

+  Copyright (c) 2014 - 2020, Linaro Ltd. All rights reserved.<BR>

+  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+**/

+

+#include <Library/BaseLib.h>

+#include <Library/FdtSerialPortAddressLib.h>

+#include <libfdt.h>

+

+/**

+  Read the "reg" property of Node in DeviceTree as a UINT64 base address.

+

+  @param[in] DeviceTree    The flat device tree (FDT) to scan.

+

+  @param[in] Node          The node to read the "reg" property of.

+

+  @param[out] BaseAddress  On success, the base address read out of Node's "reg"

+                           property. On error, not modified.

+

+  @retval RETURN_DEVICE_ERROR     Node has a "status" property with value

+                                  different from "okay".

+

+  @retval RETURN_NOT_FOUND        Node does not have a "reg" property.

+

+  @retval RETURN_BAD_BUFFER_SIZE  The size of Node's "reg" property is not 16

+                                  bytes.

+

+  @retval RETURN_SUCCESS          BaseAddress has been populated.

+**/

+STATIC

+RETURN_STATUS

+GetBaseAddress (

+  IN  CONST VOID  *DeviceTree,

+  IN  INT32       Node,

+  OUT UINT64      *BaseAddress

+  )

+{

+  CONST CHAR8  *NodeStatus;

+  CONST VOID   *RegProp;

+  INT32        PropSize;

+

+  NodeStatus = fdt_getprop (DeviceTree, Node, "status", NULL);

+  if ((NodeStatus != NULL) && (AsciiStrCmp (NodeStatus, "okay") != 0)) {

+    return RETURN_DEVICE_ERROR;

+  }

+

+  RegProp = fdt_getprop (DeviceTree, Node, "reg", &PropSize);

+  if (RegProp == NULL) {

+    return RETURN_NOT_FOUND;

+  }

+

+  if (PropSize != 16) {

+    return RETURN_BAD_BUFFER_SIZE;

+  }

+

+  *BaseAddress = fdt64_to_cpu (ReadUnaligned64 (RegProp));

+  return RETURN_SUCCESS;

+}

+

+/**

+  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

+  )

+{

+  INT32  Node;

+

+  if (fdt_check_header (DeviceTree) != 0) {

+    return RETURN_INVALID_PARAMETER;

+  }

+

+  Ports->NumberOfPorts = 0;

+  Node                 = fdt_next_node (DeviceTree, 0, NULL);

+  while ((Node > 0) &&

+         (Ports->NumberOfPorts < ARRAY_SIZE (Ports->BaseAddress)))

+  {

+    CONST CHAR8  *CompatProp;

+    INT32        PropSize;

+

+    CompatProp = fdt_getprop (DeviceTree, Node, "compatible", &PropSize);

+    if (CompatProp != NULL) {

+      CONST CHAR8  *CompatItem;

+

+      CompatItem = CompatProp;

+      while ((CompatItem < CompatProp + PropSize) &&

+             (AsciiStrCmp (CompatItem, Compatible) != 0))

+      {

+        CompatItem += AsciiStrLen (CompatItem) + 1;

+      }

+

+      if (CompatItem < CompatProp + PropSize) {

+        RETURN_STATUS  Status;

+        UINT64         BaseAddress;

+

+        Status = GetBaseAddress (DeviceTree, Node, &BaseAddress);

+        if (!RETURN_ERROR (Status)) {

+          Ports->BaseAddress[Ports->NumberOfPorts++] = BaseAddress;

+        }

+      }

+    }

+

+    Node = fdt_next_node (DeviceTree, Node, NULL);

+  }

+

+  return Ports->NumberOfPorts > 0 ? RETURN_SUCCESS : RETURN_NOT_FOUND;

+}

+

+/**

+  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

+  )

+{

+  INT32          ChosenNode;

+  CONST CHAR8    *StdoutPathProp;

+  INT32          PropSize;

+  CONST CHAR8    *StdoutPathEnd;

+  UINTN          StdoutPathLength;

+  INT32          ConsoleNode;

+  RETURN_STATUS  Status;

+

+  if (fdt_check_header (DeviceTree) != 0) {

+    return RETURN_INVALID_PARAMETER;

+  }

+

+  ChosenNode = fdt_path_offset (DeviceTree, "/chosen");

+  if (ChosenNode < 0) {

+    return RETURN_NOT_FOUND;

+  }

+

+  StdoutPathProp = fdt_getprop (

+                     DeviceTree,

+                     ChosenNode,

+                     "stdout-path",

+                     &PropSize

+                     );

+  if (StdoutPathProp == NULL) {

+    return RETURN_NOT_FOUND;

+  }

+

+  //

+  // If StdoutPathProp contains a colon (":"), then the colon terminates the

+  // path we're interested in.

+  //

+  StdoutPathEnd = AsciiStrStr (StdoutPathProp, ":");

+  if (StdoutPathEnd == NULL) {

+    StdoutPathLength = PropSize - 1;

+  } else {

+    StdoutPathLength = StdoutPathEnd - StdoutPathProp;

+  }

+

+  if (StdoutPathLength == 0) {

+    return RETURN_PROTOCOL_ERROR;

+  }

+

+  if (StdoutPathProp[0] == '/') {

+    //

+    // StdoutPathProp starts with an absolute node path.

+    //

+    ConsoleNode = fdt_path_offset_namelen (

+                    DeviceTree,

+                    StdoutPathProp,

+                    (INT32)StdoutPathLength

+                    );

+  } else {

+    //

+    // StdoutPathProp starts with an alias.

+    //

+    CONST CHAR8  *ResolvedStdoutPath;

+

+    ResolvedStdoutPath = fdt_get_alias_namelen (

+                           DeviceTree,

+                           StdoutPathProp,

+                           (INT32)StdoutPathLength

+                           );

+    if (ResolvedStdoutPath == NULL) {

+      return RETURN_NOT_FOUND;

+    }

+

+    ConsoleNode = fdt_path_offset (DeviceTree, ResolvedStdoutPath);

+  }

+

+  if (ConsoleNode < 0) {

+    return RETURN_NOT_FOUND;

+  }

+

+  Status = GetBaseAddress (DeviceTree, ConsoleNode, BaseAddress);

+  switch (Status) {

+    case RETURN_NOT_FOUND:

+    case RETURN_BAD_BUFFER_SIZE:

+      return RETURN_PROTOCOL_ERROR;

+    case RETURN_SUCCESS:

+      return RETURN_SUCCESS;

+    default:

+      return RETURN_NOT_FOUND;

+  }

+}

diff --git a/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.inf b/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.inf
new file mode 100644
index 0000000000..ae6d0d374b
--- /dev/null
+++ b/ArmVirtPkg/Library/FdtSerialPortAddressLib/FdtSerialPortAddressLib.inf
@@ -0,0 +1,27 @@
+## @file

+# Determine the base addresses of serial ports from the Device Tree.

+#

+# Copyright (C) Red Hat

+#

+# SPDX-License-Identifier: BSD-2-Clause-Patent

+##

+

+[Defines]

+  INF_VERSION    = 1.27

+  BASE_NAME      = FdtSerialPortAddressLib

+  FILE_GUID      = AEBE813B-25EA-40E5-95C4-2B864FE1E951

+  MODULE_TYPE    = BASE

+  VERSION_STRING = 1.0

+  LIBRARY_CLASS  = FdtSerialPortAddressLib

+

+[Sources]

+  FdtSerialPortAddressLib.c

+

+[Packages]

+  ArmVirtPkg/ArmVirtPkg.dec

+  EmbeddedPkg/EmbeddedPkg.dec

+  MdePkg/MdePkg.dec

+

+[LibraryClasses]

+  BaseLib

+  FdtLib