Re: [Xen-devel] [PATCH v7 1/4] dtb: correct handling of #address-cells and #size-cells.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Mon, 18 Feb 2013, Ian Campbell wrote:
> If a node does not have #*-cells then the parent's value should be
> used. Currently we were asssuming zero which is useless.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>


Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

> v7: assert we don't skip any levels in the tree
> ---
>  xen/arch/arm/domain_build.c   |    9 +++++++--
>  xen/common/device_tree.c      |   12 ++++++++----
>  xen/include/xen/device_tree.h |    3 ++-
>  3 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 7403f1a..9ce661b 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -195,11 +195,16 @@ static int write_nodes(struct domain *d, struct 
> kernel_info *kinfo,
>              continue;
>          }
>  
> +        /* We cannot handle descending more than one level at a time */
> +        ASSERT( depth <= last_depth + 1 );
> +
>          while ( last_depth-- >= depth )
>              fdt_end_node(kinfo->fdt);
>  
> -        address_cells[depth] = device_tree_get_u32(fdt, node, 
> "#address-cells");
> -        size_cells[depth] = device_tree_get_u32(fdt, node, "#size-cells");
> +        address_cells[depth] = device_tree_get_u32(fdt, node, 
> "#address-cells",
> +                                    depth > 0 ? address_cells[depth-1] : 0);
> +        size_cells[depth] = device_tree_get_u32(fdt, node, "#size-cells",
> +                                    depth > 0 ? size_cells[depth-1] : 0);
>  
>          fdt_begin_node(kinfo->fdt, name);
>  
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index 5301d63..f3d3aa1 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -120,13 +120,14 @@ void device_tree_set_reg(u32 **cell, u32 address_cells, 
> u32 size_cells,
>      set_val(cell, size_cells, size);
>  }
>  
> -u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name)
> +u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name,
> +                        u32 dflt)
>  {
>      const struct fdt_property *prop;
>  
>      prop = fdt_get_property(fdt, node, prop_name, NULL);
>      if ( !prop || prop->len < sizeof(u32) )
> -        return 0; /* default to 0 */
> +        return dflt;
>  
>      return fdt32_to_cpu(*(uint32_t*)prop->data);
>  }
> @@ -164,8 +165,11 @@ int device_tree_for_each_node(const void *fdt,
>              continue;
>          }
>  
> -        address_cells[depth] = device_tree_get_u32(fdt, node, 
> "#address-cells");
> -        size_cells[depth] = device_tree_get_u32(fdt, node, "#size-cells");
> +        address_cells[depth] = device_tree_get_u32(fdt, node, 
> "#address-cells",
> +                                depth > 0 ? address_cells[depth-1] : 0);
> +        size_cells[depth] = device_tree_get_u32(fdt, node, "#size-cells",
> +                                depth > 0 ? size_cells[depth-1] : 0);
> +
>  
>          ret = func(fdt, node, name, depth,
>                     address_cells[depth-1], size_cells[depth-1], data);
> diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
> index 1d04e4f..19bda98 100644
> --- a/xen/include/xen/device_tree.h
> +++ b/xen/include/xen/device_tree.h
> @@ -66,7 +66,8 @@ void device_tree_get_reg(const u32 **cell, u32 
> address_cells, u32 size_cells,
>                           u64 *start, u64 *size);
>  void device_tree_set_reg(u32 **cell, u32 address_cells, u32 size_cells,
>                           u64 start, u64 size);
> -u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name);
> +u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name,
> +                     u32 dflt);
>  bool_t device_tree_node_matches(const void *fdt, int node, const char 
> *match);
>  bool_t device_tree_node_compatible(const void *fdt, int node, const char 
> *match);
>  int find_compatible_node(const char *compatible, int *node, int *depth,
> -- 
> 1.7.9.1
> 

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