Re: [Xen-devel] [PATCH 5/5] device tree: print a warning if a node is nested too deep

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2012-03-22 at 19:17 +0000, David Vrabel wrote:
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
> 
> Since device_tree_for_each_node() is called before printk() works, a
> variable is used to switch between using early_printk() and printk().
> 
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

(although I separately wonder if generic printk ought not to redirect to
early_printk early on)

>  xen/common/device_tree.c |   19 ++++++++++++++++++-
>  1 files changed, 18 insertions(+), 1 deletions(-)
> 
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index 8fb6d46..04619f4 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -23,6 +23,10 @@
>  struct dt_early_info __initdata early_info;
>  void *device_tree_flattened;
>  
> +/* Some device tree functions may be called both before and after the
> +   console is initialized. */
> +static void (*dt_printk)(const char *fmt, ...) = early_printk;
> +
>  bool_t device_tree_node_matches(const void *fdt, int node, const char *match)
>  {
>      const char *name;
> @@ -90,6 +94,11 @@ u32 device_tree_get_u32(const void *fdt, int node, const 
> char *prop_name)
>   * @fdt: flat device tree.
>   * @func: function to call for each node.
>   * @data: data to pass to @func.
> + *
> + * Any nodes nested at DEVICE_TREE_MAX_DEPTH or deeper are ignored.
> + *
> + * Returns 0 if all nodes were iterated over successfully.  If @func
> + * returns a negative value, that value is returned immediately.
>   */
>  int device_tree_for_each_node(const void *fdt,
>                                device_tree_node_func func, void *data)
> @@ -104,13 +113,19 @@ int device_tree_for_each_node(const void *fdt,
>            node >=0 && depth >= 0;
>            node = fdt_next_node(fdt, node, &depth) )
>      {
> +        const char *name = fdt_get_name(fdt, node, NULL);
> +
>          if ( depth >= DEVICE_TREE_MAX_DEPTH )
> +        {
> +            dt_printk("Warning: device tree node `%s' is nested too deep\n",
> +                      name);
>              continue;
> +        }
>  
>          address_cells[depth] = device_tree_get_u32(fdt, node, 
> "#address-cells");
>          size_cells[depth] = device_tree_get_u32(fdt, node, "#size-cells");
>  
> -        ret = func(fdt, node, fdt_get_name(fdt, node, NULL), depth,
> +        ret = func(fdt, node, name, depth,
>                     address_cells[depth-1], size_cells[depth-1], data);
>          if ( ret < 0 )
>              return ret;
> @@ -253,6 +268,8 @@ size_t __init device_tree_early_init(const void *fdt)
>      device_tree_for_each_node((void *)fdt, early_scan_node, NULL);
>      early_print_info();
>  
> +    dt_printk = printk;
> +
>      return fdt_totalsize(fdt);
>  }
>  



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