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

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

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 ) {
+            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;
 }
-- 
1.7.12.1


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