linux/arch/powerpc/boot/flatdevtree_misc.c
David Gibson 35af89eb49 [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>
2006-12-04 20:39:34 +11:00

52 lines
1.3 KiB
C

/*
* This file does the necessary interface mapping between the bootwrapper
* device tree operations and the interface provided by shared source
* files flatdevicetree.[ch].
*
* Author: Mark A. Greer <mgreer@mvista.com>
*
* 2006 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <stddef.h>
#include "flatdevtree.h"
#include "ops.h"
static struct ft_cxt cxt;
static void *ft_finddevice(const char *name)
{
return ft_find_device(&cxt, name);
}
static int ft_getprop(const void *phandle, const char *propname, void *buf,
const int buflen)
{
return ft_get_prop(&cxt, phandle, propname, buf, buflen);
}
static int ft_setprop(const void *phandle, const char *propname,
const void *buf, const int buflen)
{
return ft_set_prop(&cxt, phandle, propname, buf, buflen);
}
static unsigned long ft_finalize(void)
{
ft_end_tree(&cxt);
return (unsigned long)cxt.bph;
}
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.finalize = ft_finalize;
return ft_open(&cxt, dt_blob, max_size, max_find_device,
platform_ops.realloc);
}