[PATCH 08/36] m68k: init the MMU hardware for the 54xx ColdFire

gerg
2011-10-25T07:19:22Z

If we want to run with the MMU enabled on the 54xx ColdFire CPUs then
we need to initialize it at startup. We also need to reserve some space
for the kernel's page table directory.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
arch/m68k/platform/coldfire/head.S | 38 +++++++++++++++++++++++++++++++++++-
1 files changed, 37 insertions(+), 1 deletions(-)

diff --git a/arch/m68k/platform/coldfire/head.S b/arch/m68k/platform/coldfire/head.S
index c334838..00ba371 100644
--- a/arch/m68k/platform/coldfire/head.S
+++ b/arch/m68k/platform/coldfire/head.S
@@ -3,7 +3,7 @@
/*
* head.S -- common startup code for ColdFire CPUs.
*
- * (C) Copyright 1999-2010, Greg Ungerer <gerg@snapgear.com>.
+ * (C) Copyright 1999-2011, Greg Ungerer <gerg@snapgear.com>.
*/

/*****************************************************************************/
@@ -13,6 +13,7 @@
#include <asm/asm-offsets.h>
#include <asm/coldfire.h>
#include <asm/mcfsim.h>
+#include <asm/mcfmmu.h>
#include <asm/thread_info.h>

/*****************************************************************************/
@@ -135,6 +136,14 @@ _init_sp:

__HEAD

+#ifdef CONFIG_MMU
+_start0:
+ jmp _start
+.global kernel_pg_dir
+.equ kernel_pg_dir,_start0
+.equ .,_start0+0x1000
+#endif
+
/*
* This is the codes first entry point. This is where it all
* begins...
@@ -193,6 +202,26 @@ _start:
movec %d0,%CACR
nop

+#ifdef CONFIG_MMU
+ /*
+ * Identity mapping for the kernel region.
+ */
+ movel #(MMUBASE+1),%d0 /* enable MMUBAR registers */
+ movec %d0,%MMUBAR
+ movel #MMUOR_CA,%d0 /* clear TLB entries */
+ movel %d0,MMUOR
+ movel #0,%d0 /* set ASID to 0 */
+ movec %d0,%asid
+
+ movel #MMUCR_EN,%d0 /* Enable the identity map */
+ movel %d0,MMUCR
+ nop /* sync i-pipeline */
+
+ movel #_vstart,%a0 /* jump to "virtual" space */
+ jmp %a0@
+_vstart:
+#endif /* CONFIG_MMU */
+
#ifdef CONFIG_ROMFS_FS
/*
* Move ROM filesystem above bss :-)
@@ -238,6 +267,13 @@ _clear_bss:
lea init_thread_union,%a0
lea THREAD_SIZE(%a0),%sp

+#ifdef CONFIG_MMU
+.global m68k_machtype
+ movel #MACH_M54XX,%d0
+ movel %d0,m68k_machtype /* Mark us as a ColdFire */
+ lea init_task,%a2 /* Set "current" init task */
+#endif
+
/*
* Assember start up done, start code proper.
*/
--
1.7.0.4