m68k: add ColdFire 54xx CPU MMU memory init code

Add code to the 54xx ColdFire CPU init to setup memory ready for the m68k
paged memory start up.

Some of the RAM variables that were specific to the non-mmu code paths
now need to be used during this setup, so when CONFIG_MMU is enabled.
Move these out of page_no.h and into page.h.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Matt Waddel <mwaddel@yahoo.com>
Acked-by: Kurt Mahan <kmahan@xmission.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/include/asm/page.h

@@ -36,6 +36,10 @@ typedef struct page *pgtable_t;
 #define __pgd(x)	((pgd_t) { (x) } )
 #define __pgprot(x)	((pgprot_t) { (x) } )
 
+extern unsigned long _rambase;
+extern unsigned long _ramstart;
+extern unsigned long _ramend;
+
 #endif /* !__ASSEMBLY__ */
 
 #ifdef CONFIG_MMU

arch/m68k/include/asm/page_no.h

@@ -5,9 +5,6 @@
  
 extern unsigned long memory_start;
 extern unsigned long memory_end;
-extern unsigned long _rambase;
-extern unsigned long _ramstart;
-extern unsigned long _ramend;
 
 #define get_user_page(vaddr)		__get_free_page(GFP_KERNEL)
 #define free_user_page(page, addr)	free_page(addr)

arch/m68k/platform/54xx/config.c

@@ -13,11 +13,17 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/bootmem.h>
+#include <asm/pgalloc.h>
 #include <asm/machdep.h>
 #include <asm/coldfire.h>
 #include <asm/m54xxsim.h>
 #include <asm/mcfuart.h>
 #include <asm/m54xxgpt.h>
+#ifdef CONFIG_MMU
+#include <asm/mmu_context.h>
+#endif
 
 /***************************************************************************/
 
@@ -95,8 +101,49 @@ static void mcf54xx_reset(void)
 
 /***************************************************************************/
 
+#ifdef CONFIG_MMU
+
+unsigned long num_pages;
+
+static void __init mcf54xx_bootmem_alloc(void)
+{
+	unsigned long start_pfn;
+	unsigned long memstart;
+
+	/* _rambase and _ramend will be naturally page aligned */
+	m68k_memory[0].addr = _rambase;
+	m68k_memory[0].size = _ramend - _rambase;
+
+	/* compute total pages in system */
+	num_pages = (_ramend - _rambase) >> PAGE_SHIFT;
+
+	/* page numbers */
+	memstart = PAGE_ALIGN(_ramstart);
+	min_low_pfn = _rambase >> PAGE_SHIFT;
+	start_pfn = memstart >> PAGE_SHIFT;
+	max_low_pfn = _ramend >> PAGE_SHIFT;
+	high_memory = (void *)_ramend;
+
+	m68k_virt_to_node_shift = fls(_ramend - _rambase - 1) - 6;
+	module_fixup(NULL, __start_fixup, __stop_fixup);
+
+	/* setup bootmem data */
+	m68k_setup_node(0);
+	memstart += init_bootmem_node(NODE_DATA(0), start_pfn,
+		min_low_pfn, max_low_pfn);
+	free_bootmem_node(NODE_DATA(0), memstart, _ramend - memstart);
+}
+
+#endif /* CONFIG_MMU */
+
+/***************************************************************************/
+
 void __init config_BSP(char *commandp, int size)
 {
+#ifdef CONFIG_MMU
+	mcf54xx_bootmem_alloc();
+	mmu_context_init();
+#endif
 	mach_reset = mcf54xx_reset;
 	m54xx_uarts_init();
 }