Re: [Xen-devel] [PATCH] arm64/xen: Add missing #address-cells and #size-cells properties

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

On Wed, Nov 29, 2017 at 05:08:12PM +0000, Julien Grall wrote:
> The properties #address-cells and #size-cells are used to know the
> number of cells for ranges provided by "regs". If they don't exist, the
> value are resp. 2 and 1.
>
> Currently, when multiboot nodes are created it is assumed that #address-cells

IIRC ARM boot protocol is not related to Multiboot protocol in any way.
So, calling it in that way is very confusing. Could you invent a better
not confusion name. Or at least provide a spec. I am happy to see it
in GRUB2 tree.

> and #size-cells are exactly 2. However, they are never set by GRUB and
> will result to later failure when the device-tree is generated by GRUB
> or contain different values.
>
> To prevent this failure, create the both properties in the chosen nodes.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> ---
>  grub-core/loader/arm64/xen_boot.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/grub-core/loader/arm64/xen_boot.c 
> b/grub-core/loader/arm64/xen_boot.c
> index c95d6c5a8..6780b1f0c 100644
> --- a/grub-core/loader/arm64/xen_boot.c
> +++ b/grub-core/loader/arm64/xen_boot.c
> @@ -115,6 +115,17 @@ prepare_xen_hypervisor_params (void *xen_boot_fdt)
>    if (chosen_node < 1)
>      return grub_error (GRUB_ERR_IO, "failed to get chosen node in FDT");
>
> +  /*
> +   * The address and size are always written using 64-bits value. Set

Here you say "64-bits value"...

> +   * #address-cells and #size-cells accordingly.
> +   */
> +  retval = grub_fdt_set_prop32 (xen_boot_fdt, chosen_node, "#address-cells", 
> 2);

...and then call grub_fdt_set_prop32(). I am confused...

> +  if (retval)
> +    return grub_error (GRUB_ERR_IO, "failed to set #address-cells");
> +  retval = grub_fdt_set_prop32 (xen_boot_fdt, chosen_node, "#size-cells", 2);

Ditto.

Daniel

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