// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*/
#include <linux/init.h>
#include <linux/memblock.h>
#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/code-patching.h>
#include <asm/smp.h>
#include <mm/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;
unsigned long tlb_47x_boltmap[1024/8];
static void __init ppc44x_update_tlb_hwater(void)
{
/* 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
*/
modify_instruction_site(&patch__tlb_44x_hwater_D, 0xffff, tlb_44x_hwater);
modify_instruction_site(&patch__tlb_44x_hwater_I, 0xffff, tlb_44x_hwater);
}
/*
* "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 44x type MMU
*/
static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys)
{
unsigned int entry = tlb_44x_hwater--;
ppc44x_update_tlb_hwater();
mtspr(SPRN_MMUCR, 0);
__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));
}
static int __init ppc47x_find_free_bolted(void)
{
unsigned int mmube0 = mfspr(SPRN_MMUBE0);
unsigned int mmube1 = mfspr(SPRN_MMUBE1);
if (!(mmube0 & MMUBE0_VBE0))
return 0;
if (!(mmube0 & MMUBE0_VBE1))
return 1;
if (!(mmube0 & MMUBE0_VBE2))
return 2;
if (!(mmube1 & MMUBE1_VBE3))
return 3;
if (!(mmube1 & MMUBE1_VBE4))
return 4;
if (!(mmube1 & MMUBE1_VBE5))
return 5;
return -1;
}
static void __init ppc47x_update_boltmap(void)
{
unsigned int mmube0 = mfspr(SPRN_MMUBE0);
unsigned int mmube1 = mfspr(SPRN_MMUBE1);
if (mmube0 & MMUBE0_VBE0)
__set_bit((mmube0 >> MMUBE0_IBE0_SHIFT) & 0xff,
tlb_47x_boltmap);
if (mmube0 & MMUBE0_VBE1)
__set_bit((mmube0 >> MMUBE0_IBE1_SHIFT) & 0xff,
tlb_47x_boltmap);
if (mmube0 & MMUBE0_VBE2)
__set_bit((mmube0 >> MMUBE0_IBE2_SHIFT) & 0xff,
tlb_47x_boltmap);
if (mmube1 & MMUBE1_VBE3)
__set_bit((mmube1 >> MMUBE1_IBE3_SHIFT) & 0xff,
tlb_47x_boltmap);
if (mmube1 & MMUBE1_VBE4)
__set_bit((mmube1 >> MMUBE1_IBE4_SHIFT) & 0xff,
tlb_47x_boltmap);
if (mmube1 & MMUBE1_VBE5)
__set_bit((mmube1 >> MMUBE1_IBE5_SHIFT) & 0xff,
tlb_47x_boltmap);
}
/*
* "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 47x type MMU
*/
static void __init ppc47x_pin_tlb(unsigned int virt, unsigned int phys)
{
unsigned int rA;
int bolted;
/* Base rA is HW way select, way 0, bolted bit set */
rA = 0x88000000;
/* Look for a bolted entry slot */
bolted = ppc47x_find_free_bolted();
BUG_ON(bolted < 0);
/* Insert bolted slot number */
rA |= bolted << 24;
pr_debug("256M TLB entry for 0x%08x->0x%08x in bolt slot %d\n",
virt, phys, bolted);
mtspr(SPRN_MMUCR, 0);
__asm__ __volatile__(
"tlbwe %2,%3,0\n"
"tlbwe %1,%3,1\n"
"tlbwe %0,%3,2\n"
:
: "r" (PPC47x_TLB2_SW | PPC47x_TLB2_SR |
PPC47x_TLB2_SX
#ifdef CONFIG_SMP
| PPC47x_TLB2_M
#endif
),
"r" (phys),
"r" (virt | PPC47x_TLB0_VALID | PPC47x_TLB0_256M),
"r" (rA));
}
void __init MMU_init_hw(void)
{
/* This is not useful on 47x but won't hurt either */
ppc44x_update_tlb_hwater();
flush_instruction_cache();
}
unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
{
unsigned long addr;
unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1);
/* Pin in enough TLBs to cover any lowmem not covered by the
* initial 256M mapping established in head_44x.S */
for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr;
addr += PPC_PIN_SIZE) {
if (mmu_has_feature(MMU_FTR_TYPE_47x))
ppc47x_pin_tlb(addr + PAGE_OFFSET, addr);
else
ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
}
if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
ppc47x_update_boltmap();
#ifdef DEBUG
{
int i;
printk(KERN_DEBUG "bolted entries: ");
for (i = 0; i < 255; i++) {
if (test_bit(i, tlb_47x_boltmap))
printk("%d ", i);
}
printk("\n");
}
#endif /* DEBUG */
}
return total_lowmem;
}
void setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
{
u64 size;
#ifndef CONFIG_NONSTATIC_KERNEL
/* We don't currently support the first MEMBLOCK not mapping 0
* physical on those processors
*/
BUG_ON(first_memblock_base != 0);
#endif
/* 44x has a 256M TLB entry pinned at boot */
size = (min_t(u64, first_memblock_size, PPC_PIN_SIZE));
memblock_set_current_limit(first_memblock_base + size);
}
#ifdef CONFIG_SMP
void __init mmu_init_secondary(int cpu)
{
unsigned long addr;
unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1);
/* Pin in enough TLBs to cover any lowmem not covered by the
* initial 256M mapping established in head_44x.S
*
* WARNING: This is called with only the first 256M of the
* linear mapping in the TLB and we can't take faults yet
* so beware of what this code uses. It runs off a temporary
* stack. current (r2) isn't initialized, smp_processor_id()
* will not work, current thread info isn't accessible, ...
*/
for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr;
addr += PPC_PIN_SIZE) {
if (mmu_has_feature(MMU_FTR_TYPE_47x))
ppc47x_pin_tlb(addr + PAGE_OFFSET, addr);
else
ppc44x_pin_tlb(addr + PAGE_OFFSET, addr);
}
}
#endif /* CONFIG_SMP */