/*
* Modifications by Matt Porter (mporter@mvista.com) to support
* PPC44x Book E processors.
*
* This file contains the routines for initializing the MMU
* on the 4xx series of chips.
* -- paulus
*
* Derived from arch/ppc/mm/init.c:
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
* and Cort Dougan (PReP) (cort@cs.nmt.edu)
* Copyright (C) 1996 Paul Mackerras
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/init.h>
#include <asm/mmu.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include "mmu_decl.h"
/* Used by the 44x TLB replacement exception handler.
* Just needed it declared someplace.
*/
unsigned int tlb_44x_index; /* = 0 */
unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS;
int icache_44x_need_flush;
static void __init ppc44x_update_tlb_hwater(void)
{
extern unsigned int tlb_44x_patch_hwater_D[];
extern unsigned int tlb_44x_patch_hwater_I[];
/* The TLB miss handlers hard codes the watermark in a cmpli
* instruction to improve performances rather than loading it
* from the global variable. Thus, we patch the instructions
* in the 2 TLB miss handlers when updating the value
*/
tlb_44x_patch_hwater_D[0] = (tlb_44x_patch_hwater_D[0] & 0xffff0000) |
tlb_44x_hwater;
flush_icache_range((unsigned long)&tlb_44x_patch_hwater_D[0],
(unsigned long)&tlb_44x_patch_hwater_D[1]);
tlb_44x_patch_hwater_I[0] = (tlb_44x_patch_hwater_I[0] & 0xffff0000) |
tlb_44x_hwater;
flush_icache_range((unsigned long)&tlb_44x_patch_hwater_I[0],
(unsigned long)&tlb_44x_patch_hwater_I[1]);
}
/*
* "Pins" a 256MB TLB entry in AS0 for kernel lowmem
*/
static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys)
{
unsigned int entry = tlb_44x_hwater--;
ppc44x_update_tlb_hwater();
__asm__ __volatile__(
"tlbwe %2,%3,%4\n"
"tlbwe %1,%3,%5\n"
"tlbwe %0,%3,%6\n"
:
: "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G),
"r" (phys),
"r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M),
"r" (entry),
"i" (PPC44x_TLB_PAGEID),
"i" (PPC44x_TLB_XLAT),
"i" (PPC44x_TLB_ATTRIB));
}
void __init MMU_init_hw(void)
{
ppc44x_update_tlb_hwater();
flush_instruction_cache();
}
unsigned long __init mmu_mapin_ram(unsigned long top)
{
unsigned long addr;
/* Pin in enough TLBs to cover any lowmem not covered by the
* initial 256M mapping established in head_44x.S */
for (addr = PPC_PIN_SIZE; addr < lowmem_end_addr;
addr += PPC_PIN_SIZE)
ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
return total_lowmem;
}
