Re: [PATCH] ARM/multiboot: use more flexible node naming

["Egger, Christoph" <chegger@amazon.de>]

Is there a chance to get NetBSD Dom0 [1] to boot to justify that your
approach is *really* generic.

xen,linux-zimage and xen,linux-initrd do not sound generic
but xen,dom0-kernel and xen,ramdisk do sound generic at least.

Christoph

[1] NetBSD Dom0 hasn't been ported to ARM yet.


On 05.09.13 15:43, Andre Przywara wrote:
> For the current "multiboot" on ARM support we look for a compatible
> string of "xen,multiboot-module" in the device tree, and then
> use "xen,linux-zimage" and "xen,linux-initrd" to differentiate
> between the two supported module types.
> To meet the more generic multiboot proposal in the device tree [1],
> allow Xen to be more flexible in the compatible naming and also use
> the new generic base name "boot,module".
> The mapping to either Dom0 kernel or RAM disk works either by
> providing a more specific name ("xen,dom0-kernel" and "xen,ramdisk"),
> or by using the enumeration order of the device tree nodes
> (module@0 = kernel, module@1 = initrd). This allows bootloaders
> without any specific Xen knowledge to boot Xen anyways.
> 
> [1] http://lists.xen.org/archives/html/xen-devel/2013-09/msg00083.html
> 
> Signed-off-by: Andre Przywara <andre.przywara@linaro.org>
> ---
>  xen/common/device_tree.c | 57 ++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 50 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index ec0d5e2..e10c035 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -439,22 +439,63 @@ static void __init process_cpu_node(const void *fdt, int node,
>      cpumask_set_cpu(start, &cpu_possible_map);
>  }
>  
> +static const char * const kernel_module_names[] = {
> +	"xen,linux-zimage",
> +	"xen,dom0-kernel",
> +	"boot,kernel",
> +	NULL
> +};
> +
> +static const char * const initrd_module_names[] = {
> +	"xen,linux-initrd",
> +	"xen,ramdisk",
> +	"boot,ramdisk",
> +	NULL
> +};
> +
>  static void __init process_multiboot_node(const void *fdt, int node,
>                                            const char *name,
>                                            u32 address_cells, u32 size_cells)
>  {
>      const struct fdt_property *prop;
>      const u32 *cell;
> -    int nr;
> +    int nr = -1;
>      struct dt_mb_module *mod;
>      int len;
> +    const char* const * name_list;
>  
> -    if ( fdt_node_check_compatible(fdt, node, "xen,linux-zimage") == 0 )
> -        nr = MOD_KERNEL;
> -    else if ( fdt_node_check_compatible(fdt, node, "xen,linux-initrd") == 0)
> -        nr = MOD_INITRD;
> -    else
> -        early_panic("%s not a known xen multiboot type\n", name);
> +    for (name_list = kernel_module_names; *name_list != NULL; name_list++)
> +        if ( fdt_node_check_compatible(fdt, node, *name_list) == 0 ) {
> +            nr = MOD_KERNEL;
> +            break;
> +        }
> +
> +    for (name_list = initrd_module_names; *name_list != NULL; name_list++)
> +        if ( fdt_node_check_compatible(fdt, node, *name_list) == 0 ) {
> +            nr = MOD_INITRD;
> +            break;
> +        }
> +
> +    if (nr == -1) {
> +    	char *s;
> +
> +        if ( fdt_node_check_compatible(fdt, node, "boot,module") != 0 ) {
> +            early_panic("%s not a known xen multiboot type\n", name);
> +            return;
> +        }
> +        s = strchr(name, '@');
> +        if (s == NULL)
> +            nr = early_info.modules.nr_mods + 1;
> +        else {
> +            nr = simple_strtoll(s + 1, NULL, 10) + 1;
> +        }
> +    }
> +
> +    if (nr >= NR_MODULES) {
> +        early_panic("only supporting %d multiboot modules\n",
> +            NR_MODULES - MOD_DISCARD_FIRST);
> +        return;
> +    }
>  
>      mod = &early_info.modules.module[nr];
>  
> @@ -492,6 +533,8 @@ static int __init early_scan_node(const void *fdt,
>          process_cpu_node(fdt, node, name, address_cells, size_cells);
>      else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module" ) )
>          process_multiboot_node(fdt, node, name, address_cells, size_cells);
> +    else if ( device_tree_node_compatible(fdt, node, "boot,module" ) )
> +        process_multiboot_node(fdt, node, name, address_cells, size_cells);
>  
>      return 0;
>  }
>