sh: Handle early ioremaps through fixed mappings.

This adds in a mem_init_done to work out when a standard ioremap() is
possible, falling back to the fixmap based ioremap otherwise.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/processor.h

@@ -101,6 +101,9 @@ struct seq_operations;
 
 extern struct pt_regs fake_swapper_regs;
 
+/* arch/sh/mm/init.c */
+extern unsigned int mem_init_done;
+
 /* arch/sh/kernel/setup.c */
 const char *get_cpu_subtype(struct sh_cpuinfo *c);
 extern const struct seq_operations cpuinfo_op;

arch/sh/mm/init.c

@@ -237,6 +237,8 @@ static void __init iommu_init(void)
 	no_iommu_init();
 }
 
+unsigned int mem_init_done = 0;
+
 void __init mem_init(void)
 {
 	int codesize, datasize, initsize;
@@ -287,6 +289,8 @@ void __init mem_init(void)
 
 	/* Initialize the vDSO */
 	vsyscall_init();
+
+	mem_init_done = 1;
 }
 
 void free_initmem(void)

arch/sh/mm/ioremap_32.c

@@ -1,13 +1,13 @@
 /*
  * arch/sh/mm/ioremap.c
  *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ * (C) Copyright 2005 - 2010  Paul Mundt
+ *
  * Re-map IO memory to kernel address space so that we can access it.
  * This is needed for high PCI addresses that aren't mapped in the
  * 640k-1MB IO memory area on PC's
  *
- * (C) Copyright 1995 1996 Linus Torvalds
- * (C) Copyright 2005, 2006 Paul Mundt
- *
  * This file is subject to the terms and conditions of the GNU General
  * Public License. See the file "COPYING" in the main directory of this
  * archive for more details.
@@ -64,6 +64,12 @@ void __iomem *__ioremap_caller(unsigned long phys_addr, unsigned long size,
 	phys_addr &= PAGE_MASK;
 	size = PAGE_ALIGN(last_addr+1) - phys_addr;
 
+	/*
+	 * If we can't yet use the regular approach, go the fixmap route.
+	 */
+	if (!mem_init_done)
+		return ioremap_fixed(phys_addr, size, __pgprot(flags));
+
 	/*
 	 * Ok, go for it..
 	 */