kexec: Add common device tree routines

Common device tree routines that can be shared between all arches
that have device tree support.

Signed-off-by: Geoff Levand <geoff@infradead.org>
Tested-By: Pratyush Anand <panand@redhat.com>
Tested-By: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

3 files changed, 162 insertions, 0 deletions

diff --git a/kexec/Makefile b/kexec/Makefile
index e2aee84..cc3f08b 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -73,6 +73,10 @@ dist				+= kexec/mem_regions.c kexec/mem_regions.h
 $(ARCH)_MEM_REGIONS		=
 KEXEC_SRCS			+= $($(ARCH)_MEM_REGIONS)
 
+dist				+= kexec/dt-ops.c kexec/dt-ops.h
+$(ARCH)_DT_OPS		=
+KEXEC_SRCS			+= $($(ARCH)_DT_OPS)
+
 include $(srcdir)/kexec/arch/alpha/Makefile
 include $(srcdir)/kexec/arch/arm/Makefile
 include $(srcdir)/kexec/arch/i386/Makefile
diff --git a/kexec/dt-ops.c b/kexec/dt-ops.c
new file mode 100644
index 0000000..915dbf5
--- /dev/null
+++ b/kexec/dt-ops.c
@@ -0,0 +1,145 @@
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <libfdt.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "kexec.h"
+#include "dt-ops.h"
+
+static const char n_chosen[] = "/chosen";
+
+static const char p_bootargs[] = "bootargs";
+static const char p_initrd_start[] = "linux,initrd-start";
+static const char p_initrd_end[] = "linux,initrd-end";
+
+int dtb_set_initrd(char **dtb, off_t *dtb_size, off_t start, off_t end)
+{
+	int result;
+	uint64_t value;
+
+	dbgprintf("%s: start %jd, end %jd, size %jd (%jd KiB)\n",
+		__func__, (intmax_t)start, (intmax_t)end,
+		(intmax_t)(end - start),
+		(intmax_t)(end - start) / 1024);
+
+	value = cpu_to_fdt64(start);
+
+	result = dtb_set_property(dtb, dtb_size, n_chosen, p_initrd_start,
+		&value, sizeof(value));
+
+	if (result)
+		return result;
+
+	value = cpu_to_fdt64(end);
+
+	result = dtb_set_property(dtb, dtb_size, n_chosen, p_initrd_end,
+		&value, sizeof(value));
+
+	if (result) {
+		dtb_delete_property(*dtb, n_chosen, p_initrd_start);
+		return result;
+	}
+
+	return 0;
+}
+
+int dtb_set_bootargs(char **dtb, off_t *dtb_size, const char *command_line)
+{
+	return dtb_set_property(dtb, dtb_size, n_chosen, p_bootargs,
+		command_line, strlen(command_line) + 1);
+}
+
+int dtb_set_property(char **dtb, off_t *dtb_size, const char *node,
+	const char *prop, const void *value, int value_len)
+{
+	int result;
+	int nodeoffset;
+	void *new_dtb;
+	int new_size;
+
+	value_len = FDT_TAGALIGN(value_len);
+
+	new_size = FDT_TAGALIGN(*dtb_size + fdt_node_len(node)
+		+ fdt_prop_len(prop, value_len));
+
+	new_dtb = malloc(new_size);
+
+	if (!new_dtb) {
+		dbgprintf("%s: malloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	result = fdt_open_into(*dtb, new_dtb, new_size);
+
+	if (result) {
+		dbgprintf("%s: fdt_open_into failed: %s\n", __func__,
+			fdt_strerror(result));
+		goto on_error;
+	}
+
+	nodeoffset = fdt_path_offset(new_dtb, node);
+	
+	if (nodeoffset == -FDT_ERR_NOTFOUND) {
+		result = fdt_add_subnode(new_dtb, nodeoffset, node);
+
+		if (result) {
+			dbgprintf("%s: fdt_add_subnode failed: %s\n", __func__,
+				fdt_strerror(result));
+			goto on_error;
+		}
+	} else if (nodeoffset < 0) {
+		dbgprintf("%s: fdt_path_offset failed: %s\n", __func__,
+			fdt_strerror(nodeoffset));
+		goto on_error;
+	}
+
+	result = fdt_setprop(new_dtb, nodeoffset, prop, value, value_len);
+
+	if (result) {
+		dbgprintf("%s: fdt_setprop failed: %s\n", __func__,
+			fdt_strerror(result));
+		goto on_error;
+	}
+
+	/*
+	 * Can't call free on dtb since dtb may have been mmaped by
+	 * slurp_file().
+	 */
+
+	result = fdt_pack(new_dtb);
+
+	if (result)
+		dbgprintf("%s: Unable to pack device tree: %s\n", __func__,
+			fdt_strerror(result));
+
+	*dtb = new_dtb;
+	*dtb_size = fdt_totalsize(*dtb);
+
+	return 0;
+
+on_error:
+	free(new_dtb);
+	return result;
+}
+
+int dtb_delete_property(char *dtb, const char *node, const char *prop)
+{
+	int result;
+	int nodeoffset = fdt_path_offset(dtb, node);
+
+	if (nodeoffset < 0) {
+		dbgprintf("%s: fdt_path_offset failed: %s\n", __func__,
+			fdt_strerror(nodeoffset));
+		return nodeoffset;
+	}
+
+	result = fdt_delprop(dtb, nodeoffset, prop);
+
+	if (result)
+		dbgprintf("%s: fdt_delprop failed: %s\n", __func__,
+			fdt_strerror(nodeoffset));
+
+	return result;
+}
diff --git a/kexec/dt-ops.h b/kexec/dt-ops.h
new file mode 100644
index 0000000..e70d15d
--- /dev/null
+++ b/kexec/dt-ops.h
@@ -0,0 +1,13 @@
+#if !defined(KEXEC_DT_OPS_H)
+#define KEXEC_DT_OPS_H
+
+#include <sys/types.h>
+
+int dtb_set_initrd(char **dtb, off_t *dtb_size, off_t start, off_t end);
+int dtb_set_bootargs(char **dtb, off_t *dtb_size, const char *command_line);
+int dtb_set_property(char **dtb, off_t *dtb_size, const char *node,
+	const char *prop, const void *value, int value_len);
+
+int dtb_delete_property(char *dtb, const char *node, const char *prop);
+
+#endif