[PATCH] powerpc: Export flat device tree via debugfs for debugging

[Kumar Gala]

On May 1, 2006, at 2:40 AM, Michael Ellerman wrote:

> If DEBUG is turned on in prom.c, export the flat device tree via  
> debugfs.
> This has been handy on several occasions.
>
> To look at it:
>  # mount -t debugfs none /sys/kernel/debug
>  # od -a /sys/kernel/debug/powerpc/flat-device-tree
>  and/or
>  # dtc -fI dtb /sys/kernel/debug/powerpc/flat-device-tree -O dts
>
> Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
> ---
>
>  arch/powerpc/kernel/prom.c |   25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>
> Index: to-merge/arch/powerpc/kernel/prom.c
> ===================================================================
> --- to-merge.orig/arch/powerpc/kernel/prom.c
> +++ to-merge/arch/powerpc/kernel/prom.c
> @@ -30,6 +30,7 @@
>  #include <linux/bitops.h>
>  #include <linux/module.h>
>  #include <linux/kexec.h>
> +#include <linux/debugfs.h>
>
>  #include <asm/prom.h>
>  #include <asm/rtas.h>
> @@ -2009,3 +2010,27 @@ void kdump_move_device_tree(void)
>  	/* XXX should we unreserve the old DT? */
>  }
>  #endif /* CONFIG_KEXEC */
> +
> +#ifdef DEBUG

Shouldn't this also depend on DEBUGFS being built in.

> +static struct debugfs_blob_wrapper flat_dt_blob;
> +
> +static int __init export_flat_device_tree(void)
> +{
> +	struct dentry *d;
> +
> +	d = debugfs_create_dir("powerpc", NULL);
> +	if (!d)
> +		return 1;
> +
> +	flat_dt_blob.data = initial_boot_params;
> +	flat_dt_blob.size = initial_boot_params->totalsize;
> +
> +	d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
> +				d, &flat_dt_blob);
> +	if (!d)
> +		return 1;
> +
> +	return 0;
> +}
> +__initcall(export_flat_device_tree);
> +#endif
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