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

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

On 09/09/2013 02:00 PM, Ian Campbell wrote:
> On Thu, 2013-09-05 at 15:43 +0200, 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@xxxxxxxxxx>
> > ---
> >   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 ) {
> I think Julien's big dtb series adds a helper which would make this
> simpler?
>
> That could be a later fix up, are there any other ordering constraints
> with that series?
Not that I am aware of. I think I will send out my new version so far 
for discussion and review and will happily rebase it later on if needed.
Thanks,
Andre.



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