efi/dtb: Find potential FDT on UEFI

* Makes our UEFI bootloader somewhat FDT/DTB aware on all
  architectures.
* Will report when an FDT is found, and provide it to kernels
  that want it.

Change-Id: I90324fc0579a9c835e60568fa9b654c2df0aba27
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3543
Reviewed-by: Fredrik Holmqvist <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>

headers/private/kernel/arch/arm/arch_kernel_args.h

@@ -30,6 +30,7 @@ typedef struct {
 
 	// needed for UEFI, otherwise kernel acpi support can't find ACPI root
 	FixedWidthPointer<void> acpi_root;
+	FixedWidthPointer<void> fdt;
 } _PACKED arch_kernel_args;
 
 #endif	/* KERNEL_ARCH_ARM_KERNEL_ARGS_H */

headers/private/kernel/platform/efi/types.h

@@ -68,6 +68,9 @@
     {0xeb9d2d31, 0x2d88, 0x11d3, {0x9a, 0x16, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d}}
 #define SMBIOS3_TABLE_GUID \
     {0xf2fd1544, 0x9794, 0x4a2c, {0x99, 0x2e, 0xe5, 0xbb, 0xcf, 0x20, 0xe3, 0x94}}
+#define DEVICE_TREE_GUID \
+    {0xb1b621d5, 0xf19c, 0x41a5, {0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0}}
+
 
 typedef struct {
     uint64_t Signature;

src/system/boot/platform/efi/Jamfile

@@ -23,6 +23,7 @@ local platform_src =
 	mmu.cpp
 	heap.cpp
 	acpi.cpp
+	dtb.cpp
 	timer.cpp
 	menu.cpp
 	devices.cpp

src/system/boot/platform/efi/dtb.cpp

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2019-2020 Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *   Alexander von Gluck IV <[email protected]>
+ */
+
+
+#include <boot/addr_range.h>
+#include <boot/platform.h>
+#include <boot/stage2.h>
+#include <kernel/kernel.h>
+
+#include <ByteOrder.h>
+
+#include "efi_platform.h"
+
+
+#define INFO(x...) dprintf("efi/fdt: " x)
+#define ERROR(x...) dprintf("efi/fdt: " x)
+
+
+static bool
+fdt_valid(void* fdt, uint32* size)
+{
+	if (fdt == NULL)
+		return false;
+	uint32* words = (uint32*)fdt;
+	if (B_BENDIAN_TO_HOST_INT32(words[0]) != 0xd00dfeed)
+		return false;
+	*size = B_BENDIAN_TO_HOST_INT32(words[1]);
+	if (size == 0)
+		return false;
+
+	return true;
+}
+
+
+void
+dtb_init()
+{
+	efi_configuration_table *table = kSystemTable->ConfigurationTable;
+	size_t entries = kSystemTable->NumberOfTableEntries;
+
+	INFO("Probing for device trees from UEFI...\n");
+
+	// Try to find an FDT
+	for (uint32 i = 0; i < entries; i++) {
+		if (!table[i].VendorGuid.equals(DEVICE_TREE_GUID))
+			continue;
+
+		void* dtbPtr = (void*)(table[i].VendorTable);
+
+		uint32 fdtSize = 0;
+		if (!fdt_valid(dtbPtr, &fdtSize)) {
+			ERROR("Invalid FDT from UEFI table %d\n", i);
+			break;
+		}
+
+		INFO("Valid FDT from UEFI table %d (%d)\n", i, fdtSize);
+
+		// pack into proper location if the architecture cares
+		#ifdef __ARM__
+		gKernelArgs.arch_args.fdt = kernel_args_malloc(fdtSize);
+		if (gKernelArgs.arch_args.fdt != NULL) {
+			memcpy(gKernelArgs.arch_args.fdt, dtbPtr, fdtSize);
+		} else
+			ERROR("unable to malloc for fdt!\n");
+		#endif
+	}
+}

src/system/boot/platform/efi/dtb.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2019-2020, Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef DTB_H
+#define DTB_H
+
+#ifndef _ASSEMBLER
+
+#include "efi_platform.h"
+
+#include <util/FixedWidthPointer.h>
+
+
+extern void dtb_init();
+
+
+#endif /* !_ASSEMBLER */
+
+#endif /* DTB_H */

src/system/boot/platform/efi/start.cpp

@@ -24,6 +24,7 @@
 #include "acpi.h"
 #include "console.h"
 #include "cpu.h"
+#include "dtb.h"
 #include "efi_platform.h"
 #include "mmu.h"
 #include "quirks.h"
@@ -213,6 +214,7 @@ efi_main(efi_handle image, efi_system_table *systemTable)
 
 	cpu_init();
 	acpi_init();
+	dtb_init();
 	timer_init();
 	smp_init();