[POWERPC] Add device tree utility functions to zImage

This patch adds a library of useful device tree manipulation functions
to the zImage library, for use by platform code.  These functions are
based on the hooks already in dt_ops, so they're not dependent on a
particular device tree implementation.  This patch also slightly
streamlines the code in main.c using these new functions.

This is a consolidation of my work in this area with Scott Wood's
patches to a very similar end.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 11 insertions, 16 deletions

diff --git a/arch/powerpc/boot/main.c b/arch/powerpc/boot/main.c
index e1df8feaf16d..ab9dfe2b38f1 100644
--- a/arch/powerpc/boot/main.c
+++ b/arch/powerpc/boot/main.c
@@ -153,13 +153,10 @@ static struct addr_range prep_kernel(void)
         return (struct addr_range){addr, ei.memsize};
 }
 
-static struct addr_range prep_initrd(struct addr_range vmlinux,
+static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
                                      unsigned long initrd_addr,
                                      unsigned long initrd_size)
 {
-        void *devp;
-        u32 initrd_start, initrd_end;
-
         /* If we have an image attached to us, it overrides anything
          * supplied by the loader. */
         if (_initrd_end > _initrd_start) {
@@ -198,16 +195,8 @@ static struct addr_range prep_initrd(struct addr_range vmlinux,
         printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
 
         /* Tell the kernel initrd address via device tree */
-        devp = finddevice("/chosen");
-        if (! devp)
-                fatal("Device tree has no chosen node!\n\r");
-
-        initrd_start = (u32)initrd_addr;
-        initrd_end = (u32)initrd_addr + initrd_size;
-
-        setprop(devp, "linux,initrd-start", &initrd_start,
-                sizeof(initrd_start));
-        setprop(devp, "linux,initrd-end", &initrd_end, sizeof(initrd_end));
+        setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
+        setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
 
         return (struct addr_range){(void *)initrd_addr, initrd_size};
 }
@@ -254,6 +243,7 @@ void start(void)
         kernel_entry_t kentry;
         char cmdline[COMMAND_LINE_SIZE];
         unsigned long ft_addr = 0;
+        void *chosen;
 
         if (console_ops.open && (console_ops.open() < 0))
                 exit();
@@ -263,9 +253,14 @@ void start(void)
         printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
                _start, get_sp());
 
+        /* Ensure that the device tree has a /chosen node */
+        chosen = finddevice("/chosen");
+        if (!chosen)
+                chosen = create_node(NULL, "chosen");
+
         vmlinux = prep_kernel();
-        initrd = prep_initrd(vmlinux, loader_info.initrd_addr,
-                             loader_info.initrd_size);
+        initrd = prep_initrd(vmlinux, chosen,
+                             loader_info.initrd_addr, loader_info.initrd_size);
 
         /* If cmdline came from zimage wrapper or if we can edit the one
          * in the dt, print it out and edit it, if possible.