[edk2-platforms PATCH v5 1/4] SbsaQemu: Add FdtHelperLib


Rebecca Cran
 

The CountCpusFromFdt function is now used in two places. Create
FdtHelperLib for this and similar functions.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
---
Platform/Qemu/SbsaQemu/SbsaQemu.dsc | 2 +
Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h | 24 ++++++++
Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c | 62 ++++++++++++++++++++
Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf | 28 +++++++++
4 files changed, 116 insertions(+)

diff --git a/Platform/Qemu/SbsaQemu/SbsaQemu.dsc b/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
index f6af3f9111ee..8faad3eda217 100644
--- a/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
+++ b/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
@@ -121,6 +121,8 @@ DEFINE NETWORK_HTTP_BOOT_ENABLE = FALSE
# ARM PL011 UART Driver
PL011UartLib|ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf

+ FdtHelperLib|Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
+
# Debug Support
PeCoffExtraActionLib|ArmPkg/Library/DebugPeCoffExtraActionLib/DebugPeCoffExtraActionLib.inf
DebugAgentLib|MdeModulePkg/Library/DebugAgentLibNull/DebugAgentLibNull.inf
diff --git a/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h b/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h
new file mode 100644
index 000000000000..e9e7281c1342
--- /dev/null
+++ b/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h
@@ -0,0 +1,24 @@
+/** @file
+* FdtHelperLib.h
+*
+* Copyright (c) 2021, NUVIA Inc. All rights reserved.
+*
+* SPDX-License-Identifier: BSD-2-Clause-Patent
+*
+**/
+
+#ifndef FDT_HELPER_LIB_
+#define FDT_HELPER_LIB_
+
+/** Walks through the Device Tree created by Qemu and counts the number
+ of CPUs present in it.
+
+ @return The number of CPUs present.
+**/
+EFIAPI
+UINT32
+FdtHelperCountCpus (
+ VOID
+ );
+
+#endif /* FDT_HELPER_LIB_ */
diff --git a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c
new file mode 100644
index 000000000000..411f035ee7d8
--- /dev/null
+++ b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c
@@ -0,0 +1,62 @@
+/** @file
+* FdtHelperLib.c
+*
+* Copyright (c) 2021, NUVIA Inc. All rights reserved.
+* Copyright (c) 2020, Linaro Ltd. All rights reserved.
+*
+* SPDX-License-Identifier: BSD-2-Clause-Patent
+*
+**/
+
+#include <Uefi.h>
+#include <Library/DebugLib.h>
+#include <Library/FdtHelperLib.h>
+#include <Library/PcdLib.h>
+#include <libfdt.h>
+
+/** Walks through the Device Tree created by Qemu and counts the number
+ of CPUs present in it.
+
+ @return The number of CPUs present.
+**/
+EFIAPI
+UINT32
+FdtHelperCountCpus (
+ VOID
+ )
+{
+ VOID *DeviceTreeBase;
+ INT32 Node;
+ INT32 Prev;
+ INT32 CpuNode;
+ UINT32 CpuCount;
+
+ DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeBaseAddress);
+ ASSERT (DeviceTreeBase != NULL);
+
+ // Make sure we have a valid device tree blob
+ ASSERT (fdt_check_header (DeviceTreeBase) == 0);
+
+ CpuNode = fdt_path_offset (DeviceTreeBase, "/cpus");
+ if (CpuNode <= 0) {
+ DEBUG ((DEBUG_ERROR, "Unable to locate /cpus in device tree\n"));
+ return 0;
+ }
+
+ CpuCount = 0;
+
+ // Walk through /cpus node and count the number of subnodes.
+ // The count of these subnodes corresponds to the number of
+ // CPUs created by Qemu.
+ Prev = fdt_first_subnode (DeviceTreeBase, CpuNode);
+ while (1) {
+ CpuCount++;
+ Node = fdt_next_subnode (DeviceTreeBase, Prev);
+ if (Node < 0) {
+ break;
+ }
+ Prev = Node;
+ }
+
+ return CpuCount;
+}
diff --git a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
new file mode 100644
index 000000000000..d84c16f888d1
--- /dev/null
+++ b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
@@ -0,0 +1,28 @@
+#/** @file
+#
+# Component description file for FdtHelperLib module
+#
+# Copyright (c) 2021, NUVIA Inc. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#**/
+
+[Defines]
+ INF_VERSION = 1.29
+ BASE_NAME = FdtHelperLib
+ FILE_GUID = 34e4396f-c2fc-4f9e-ad58-0f98e99e3875
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = FdtHelperLib
+
+[Sources.common]
+ FdtHelperLib.c
+
+[Packages]
+ EmbeddedPkg/EmbeddedPkg.dec
+ MdePkg/MdePkg.dec
+ Silicon/Qemu/SbsaQemu/SbsaQemu.dec
+
+[FixedPcd]
+ gArmVirtSbsaQemuPlatformTokenSpaceGuid.PcdDeviceTreeBaseAddress
--
2.26.2

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