avr32: Add simple paging support
Use the MMU hardware to set up 1:1 mappings between physical and virtual
addresses. This allows us to bypass the cache when accessing the flash
without having to do any physical-to-virtual address mapping in the CFI
driver.
The virtual memory mappings are defined at compile time through a sorted
array of virtual memory range objects. When a TLB miss exception
happens, the exception handler does a binary search through the array
until it finds a matching entry and loads it into the TLB. The u-boot
image itself is covered by a fixed TLB entry which is never replaced.
This makes the 'saveenv' command work again on ATNGW100 and other boards
using the CFI driver, hopefully without breaking any rules.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/arch/avr32/lib/board.c b/arch/avr32/lib/board.c
index 9e741d2..aa589bb 100644
--- a/arch/avr32/lib/board.c
+++ b/arch/avr32/lib/board.c
@@ -33,6 +33,7 @@
#include <asm/initcalls.h>
#include <asm/sections.h>
+#include <asm/arch/mmu.h>
#ifndef CONFIG_IDENT_STRING
#define CONFIG_IDENT_STRING ""
@@ -265,6 +266,9 @@
gd->flags |= GD_FLG_RELOC;
gd->reloc_off = dest_addr - CONFIG_SYS_MONITOR_BASE;
+ /* Enable the MMU so that we can keep u-boot simple */
+ mmu_init_r(dest_addr);
+
board_early_init_r();
monitor_flash_len = _edata - _text;