powerpc/mm: Add mmu_early_init_devtree()

Empty for now, but we'll add to it in the next patch.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/book3s/64/mmu.h

@@ -107,6 +107,7 @@ extern int mmu_vmemmap_psize;
 extern int mmu_io_psize;
 
 /* MMU initialization */
+void mmu_early_init_devtree(void);
 extern void radix_init_native(void);
 extern void hash__early_init_mmu(void);
 extern void radix__early_init_mmu(void);

arch/powerpc/include/asm/mmu.h

@@ -210,6 +210,7 @@ extern void early_init_mmu(void);
 extern void early_init_mmu_secondary(void);
 extern void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				       phys_addr_t first_memblock_size);
+static inline void mmu_early_init_devtree(void) { }
 #endif /* __ASSEMBLY__ */
 #endif
 

arch/powerpc/kernel/prom.c

@@ -750,6 +750,8 @@ void __init early_init_devtree(void *params)
 	if (disable_radix)
 		cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;
 
+	mmu_early_init_devtree();
+
 #ifdef CONFIG_PPC_POWERNV
 	/* Scan and build the list of machine check recoverable ranges */
 	of_scan_flat_dt(early_init_dt_scan_recoverable_ranges, NULL);

arch/powerpc/mm/init_64.c

@@ -411,3 +411,9 @@ struct page *realmode_pfn_to_page(unsigned long pfn)
 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
 
 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */
+
+#ifdef CONFIG_PPC_STD_MMU_64
+void __init mmu_early_init_devtree(void)
+{
+}
+#endif /* CONFIG_PPC_STD_MMU_64 */