[POWERPC] Cleanup zImage handling of kernel entry with flat device tree

This makes 2 changes to clean up the flat device tree handling
logic in the zImage wrapper.

First, there were two callbacks from the dt_ops structure used for
producing a final flat tree to pass to the kerne: dt_ops.ft_pack()
which packed the flat tree (possibly a no-op) and dt_ops.ft_addr()
which retreived the address of the final blob.  Since they were only
ever called together, this patch combines the two into a single new
callback, dt_ops.finalize().  This new callback does whatever
platform-dependent things are necessary to produce a final flat device
tree blob, and returns the blob's addres.

Second, the current logic calls the kernel with a flat device tree if
one is build into the zImage wrapper, otherwise it boots the kernel
with a PROM pointer, expecting the kernel to copy the OF device tree
itself.  This approach precludes the possibility of the platform
wrapper code building a flat device tree from whatever
platform-specific information firmware provides.  Thus, this patch
takes the more sensible approach of invoking the kernel with a flat
tree if the dt_ops.finalize callback provides one (by whatever means).

So, the dt_ops.finalize callback can be NULL, or can be a function
which returns NULL.  In either case, the zImage wrapper logic assumes
that this is a platform with OF and invokes the kernel accordingly.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/powerpc/boot/flatdevtree_misc.c b/arch/powerpc/boot/flatdevtree_misc.c
index c7f9adbf827..04da38fa477 100644
--- a/arch/powerpc/boot/flatdevtree_misc.c
+++ b/arch/powerpc/boot/flatdevtree_misc.c
@@ -33,13 +33,9 @@ static int ft_setprop(const void *phandle, const char *propname,
 	return ft_set_prop(&cxt, phandle, propname, buf, buflen);
 }
 
-static void ft_pack(void)
+static unsigned long ft_finalize(void)
 {
 	ft_end_tree(&cxt);
-}
-
-static unsigned long ft_addr(void)
-{
 	return (unsigned long)cxt.bph;
 }
 
@@ -48,8 +44,7 @@ int ft_init(void *dt_blob, unsigned int max_size, unsigned int max_find_device)
 	dt_ops.finddevice = ft_finddevice;
 	dt_ops.getprop = ft_getprop;
 	dt_ops.setprop = ft_setprop;
-	dt_ops.ft_pack = ft_pack;
-	dt_ops.ft_addr = ft_addr;
+	dt_ops.finalize = ft_finalize;
 
 	return ft_open(&cxt, dt_blob, max_size, max_find_device,
 			platform_ops.realloc);