xen/dt: Extract helper to map nodes to module kinds

This will be required later by x86 code in order to do early identification
of boot modules when booting off a DTB.

Not a functional change.

Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/common/device-tree/bootfdt.c

@@ -5,6 +5,24 @@
 #include <xen/libfdt/libfdt.h>
 #include <xen/unaligned.h>
 
+boot_module_kind __init fdt_node_to_kind(const void *fdt, int node)
+{
+    if ( fdt_node_check_compatible(fdt, node, "xen,linux-zimage") == 0 ||
+         fdt_node_check_compatible(fdt, node, "multiboot,kernel") == 0 )
+        return BOOTMOD_KERNEL;
+    if ( fdt_node_check_compatible(fdt, node, "xen,linux-initrd") == 0 ||
+         fdt_node_check_compatible(fdt, node, "multiboot,ramdisk") == 0 )
+        return BOOTMOD_RAMDISK;
+    if ( fdt_node_check_compatible(fdt, node, "xen,xsm-policy") == 0 )
+        return BOOTMOD_XSM_POLICY;
+    if ( fdt_node_check_compatible(fdt, node, "multiboot,device-tree") == 0 )
+        return BOOTMOD_GUEST_DTB;
+    if ( fdt_node_check_compatible(fdt, node, "multiboot,microcode") == 0 )
+        return BOOTMOD_MICROCODE;
+
+    return BOOTMOD_UNKNOWN;
+}
+
 void __init device_tree_get_reg(const __be32 **cell, uint32_t address_cells,
                                 uint32_t size_cells, paddr_t *start,
                                 paddr_t *size)

xen/common/device-tree/bootinfo-fdt.c

@@ -237,21 +237,7 @@ static void __init process_multiboot_node(const void *fdt, int node,
 
     cell = (const __be32 *)prop->data;
     device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
-
-    if ( fdt_node_check_compatible(fdt, node, "xen,linux-zimage") == 0 ||
-         fdt_node_check_compatible(fdt, node, "multiboot,kernel") == 0 )
-        kind = BOOTMOD_KERNEL;
-    else if ( fdt_node_check_compatible(fdt, node, "xen,linux-initrd") == 0 ||
-              fdt_node_check_compatible(fdt, node, "multiboot,ramdisk") == 0 )
-        kind = BOOTMOD_RAMDISK;
-    else if ( fdt_node_check_compatible(fdt, node, "xen,xsm-policy") == 0 )
-        kind = BOOTMOD_XSM_POLICY;
-    else if ( fdt_node_check_compatible(fdt, node, "multiboot,device-tree") == 0 )
-        kind = BOOTMOD_GUEST_DTB;
-    else if ( fdt_node_check_compatible(fdt, node, "multiboot,microcode") == 0 )
-        kind = BOOTMOD_MICROCODE;
-    else
-        kind = BOOTMOD_UNKNOWN;
+    kind = fdt_node_to_kind(fdt, node);
 
     /**
      * Guess the kind of these first two unknowns respectively:

xen/include/xen/bootfdt.h

@@ -157,4 +157,11 @@ u32 device_tree_get_u32(const void *fdt, int node,
 void device_tree_get_reg(const __be32 **cell, uint32_t address_cells,
                          uint32_t size_cells, paddr_t *start, paddr_t *size);
 
+/*
+ * Probe an FDT node thought to be a boot module to identify its kind.
+ *
+ * If correctly identified, returns the detected kind, otherwise BOOTMOD_UNKNOWN
+ */
+boot_module_kind fdt_node_to_kind(const void *fdt, int node);
+
 #endif /* XEN_BOOTFDT_H */