From 00fc82f17cff9295387d516384ecdc443acb1b22 Mon Sep 17 00:00:00 2001
From: Bradley Morgan <brads@mainlining.org>
Date: Sat, 3 Oct 2026 18:57:38 +0000
Subject: tashaboot: arm64 bringup, semihosting payload loader

consoles on the pl011 the dtb points at, walks the memory node and
chosen, loads an arm64 kernel Image over semihosting and jumps to it
with the documented register state. string functions, printf and
libfdt are vendored from lk (lk2nd) and u-boot so the libc surface is
the one those projects already proved. built and booted on qemu virt,
payload exits clean through semihosting.
---
 lib/libfdt/fdt_wip.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 lib/libfdt/fdt_wip.c

(limited to 'lib/libfdt/fdt_wip.c')

diff --git a/lib/libfdt/fdt_wip.c b/lib/libfdt/fdt_wip.c
new file mode 100644
index 0000000..c2d7566
--- /dev/null
+++ b/lib/libfdt/fdt_wip.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+int fdt_setprop_inplace_namelen_partial(void *fdt, int nodeoffset,
+					const char *name, int namelen,
+					uint32_t idx, const void *val,
+					int len)
+{
+	void *propval;
+	int proplen;
+
+	propval = fdt_getprop_namelen_w(fdt, nodeoffset, name, namelen,
+					&proplen);
+	if (!propval)
+		return proplen;
+
+	if ((unsigned)proplen < (len + idx))
+		return -FDT_ERR_NOSPACE;
+
+	memcpy((char *)propval + idx, val, len);
+	return 0;
+}
+
+int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,
+			const void *val, int len)
+{
+	const void *propval;
+	int proplen;
+
+	propval = fdt_getprop(fdt, nodeoffset, name, &proplen);
+	if (!propval)
+		return proplen;
+
+	if (proplen != len)
+		return -FDT_ERR_NOSPACE;
+
+	return fdt_setprop_inplace_namelen_partial(fdt, nodeoffset, name,
+						   strlen(name), 0,
+						   val, len);
+}
+
+static void fdt_nop_region_(void *start, int len)
+{
+	fdt32_t *p;
+
+	for (p = start; (char *)p < ((char *)start + len); p++)
+		*p = cpu_to_fdt32(FDT_NOP);
+}
+
+int fdt_nop_property(void *fdt, int nodeoffset, const char *name)
+{
+	struct fdt_property *prop;
+	int len;
+
+	prop = fdt_get_property_w(fdt, nodeoffset, name, &len);
+	if (!prop)
+		return len;
+
+	fdt_nop_region_(prop, len + sizeof(*prop));
+
+	return 0;
+}
+
+int fdt_node_end_offset_(void *fdt, int offset)
+{
+	int depth = 0;
+
+	while ((offset >= 0) && (depth >= 0))
+		offset = fdt_next_node(fdt, offset, &depth);
+
+	return offset;
+}
+
+int fdt_nop_node(void *fdt, int nodeoffset)
+{
+	int endoffset;
+
+	endoffset = fdt_node_end_offset_(fdt, nodeoffset);
+	if (endoffset < 0)
+		return endoffset;
+
+	fdt_nop_region_(fdt_offset_ptr_w(fdt, nodeoffset, 0),
+			endoffset - nodeoffset);
+	return 0;
+}
-- 
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