[PATCH 2/4] state: warn when a state node will be overwritten

[Uwe Kleine-König]

On Thu, May 04, 2017 at 01:02:17PM +0200, Sascha Hauer wrote:
> People do not seem to know that a state node in the kernel
> device tree will be overwritten by barebox. Print a warning
> when this happens so that people can get an idea why changes
> in the kernel device tree state node do not have any effect.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  common/state/state.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/common/state/state.c b/common/state/state.c
> index 6db77f2c18..c3c8b768c7 100644
> --- a/common/state/state.c
> +++ b/common/state/state.c
> @@ -416,6 +416,15 @@ static int of_state_fixup(struct device_node *root, void *ctx)
>  	if (node) {
>  		/* replace existing node - it will be deleted later */
>  		parent = node->parent;
> +
> +		/*
> +		 * barebox replaces the state node in the device tree it starts the
> +		 * kernel with, so a state node that already exists in the device tree
> +		 * will be overwritten. Warn about this so people do not wonder why
> +		 * changes in the kernels state node do not have any effect.
> +		 */
> +		if (root != of_get_root_node())
> +			dev_warn(&state->dev, "Warning: Kernel devicetree contains state node, replacing it\n");

Would it make sense to only issue this warning if there are differences
between the replacing and the replaced node? Otherwise I think this
warning will trigger in many cases where it doesn't really matter. At
least in my projects I take care to have only minimal differences
between barebox' and linux' device tree and so the latter usually also
contains the state stuff.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |