/*
* Altera Nios II MMU emulation for qemu.
*
* Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/lgpl-2.1.html>
*/
#include "qemu/osdep.h"
#include "qemu/qemu-print.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "mmu.h"
#if !defined(CONFIG_USER_ONLY)
/* Define this to enable MMU debug messages */
/* #define DEBUG_MMU */
#ifdef DEBUG_MMU
#define MMU_LOG(x) x
#else
#define MMU_LOG(x)
#endif
void mmu_read_debug(CPUNios2State *env, uint32_t rn)
{
switch (rn) {
case CR_TLBACC:
MMU_LOG(qemu_log("TLBACC READ %08X\n", env->regs[rn]));
break;
case CR_TLBMISC:
MMU_LOG(qemu_log("TLBMISC READ %08X\n", env->regs[rn]));
break;
case CR_PTEADDR:
MMU_LOG(qemu_log("PTEADDR READ %08X\n", env->regs[rn]));
break;
default:
break;
}
}
/* rw - 0 = read, 1 = write, 2 = fetch. */
unsigned int mmu_translate(CPUNios2State *env,
Nios2MMULookup *lu,
target_ulong vaddr, int rw, int mmu_idx)
{
Nios2CPU *cpu = env_archcpu(env);
int pid = (env->mmu.tlbmisc_wr & CR_TLBMISC_PID_MASK) >> 4;
int vpn = vaddr >> 12;
MMU_LOG(qemu_log("mmu_translate vaddr %08X, pid %08X, vpn %08X\n",
vaddr, pid, vpn));
int way;
for (way = 0; way < cpu->tlb_num_ways; way++) {
Nios2TLBEntry *entry =
&env->mmu.tlb[(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask)];
MMU_LOG(qemu_log("TLB[%d] TAG %08X, VPN %08X\n",
(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask),
entry->tag, (entry->tag >> 12)));
if (((entry->tag >> 12) != vpn) ||
(((entry->tag & (1 << 11)) == 0) &&
((entry->tag & ((1 << cpu->pid_num_bits) - 1)) != pid))) {
continue;
}
lu->vaddr = vaddr & TARGET_PAGE_MASK;
lu->paddr = (entry->data & CR_TLBACC_PFN_MASK) << TARGET_PAGE_BITS;
lu->prot = ((entry->data & CR_TLBACC_R) ? PAGE_READ : 0) |
((entry->data & CR_TLBACC_W) ? PAGE_WRITE : 0) |
((entry->data & CR_TLBACC_X) ? PAGE_EXEC : 0);
MMU_LOG(qemu_log("HIT TLB[%d] %08X %08X %08X\n",
(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask),
lu->vaddr, lu->paddr, lu->prot));
return 1;
}
return 0;
}
static void mmu_flush_pid(CPUNios2State *env, uint32_t pid)
{
CPUState *cs = env_cpu(env);
Nios2CPU *cpu = env_archcpu(env);
int idx;
MMU_LOG(qemu_log("TLB Flush PID %d\n", pid));
for (idx = 0; idx < cpu->tlb_num_entries; idx++) {
Nios2TLBEntry *entry = &env->mmu.tlb[idx];
MMU_LOG(qemu_log("TLB[%d] => %08X %08X\n",
idx, entry->tag, entry->data));
if ((entry->tag & (1 << 10)) && (!(entry->tag & (1 << 11))) &&
((entry->tag & ((1 << cpu->pid_num_bits) - 1)) == pid)) {
uint32_t vaddr = entry->tag & TARGET_PAGE_MASK;
MMU_LOG(qemu_log("TLB Flush Page %08X\n", vaddr));
tlb_flush_page(cs, vaddr);
}
}
}
void mmu_write(CPUNios2State *env, uint32_t rn, uint32_t v)
{
CPUState *cs = env_cpu(env);
Nios2CPU *cpu = env_archcpu(env);
MMU_LOG(qemu_log("mmu_write %08X = %08X\n", rn, v));
switch (rn) {
case CR_TLBACC:
MMU_LOG(qemu_log("TLBACC: IG %02X, FLAGS %c%c%c%c%c, PFN %05X\n",
v >> CR_TLBACC_IGN_SHIFT,
(v & CR_TLBACC_C) ? 'C' : '.',
(v & CR_TLBACC_R) ? 'R' : '.',
(v & CR_TLBACC_W) ? 'W' : '.',
(v & CR_TLBACC_X) ? 'X' : '.',
(v & CR_TLBACC_G) ? 'G' : '.',
v & CR_TLBACC_PFN_MASK));
/* if tlbmisc.WE == 1 then trigger a TLB write on writes to TLBACC */
if (env->regs[CR_TLBMISC] & CR_TLBMISC_WR) {
int way = (env->regs[CR_TLBMISC] >> CR_TLBMISC_WAY_SHIFT);
int vpn = (env->mmu.pteaddr_wr & CR_PTEADDR_VPN_MASK) >> 2;
int pid = (env->mmu.tlbmisc_wr & CR_TLBMISC_PID_MASK) >> 4;
int g = (v & CR_TLBACC_G) ? 1 : 0;
int valid = ((vpn & CR_TLBACC_PFN_MASK) < 0xC0000) ? 1 : 0;
Nios2TLBEntry *entry =
&env->mmu.tlb[(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask)];
uint32_t newTag = (vpn << 12) | (g << 11) | (valid << 10) | pid;
uint32_t newData = v & (CR_TLBACC_C | CR_TLBACC_R | CR_TLBACC_W |
CR_TLBACC_X | CR_TLBACC_PFN_MASK);
if ((entry->tag != newTag) || (entry->data != newData)) {
if (entry->tag & (1 << 10)) {
/* Flush existing entry */
MMU_LOG(qemu_log("TLB Flush Page (OLD) %08X\n",
entry->tag & TARGET_PAGE_MASK));
tlb_flush_page(cs, entry->tag & TARGET_PAGE_MASK);
}
entry->tag = newTag;
entry->data = newData;
MMU_LOG(qemu_log("TLB[%d] = %08X %08X\n",
(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask),
entry->tag, entry->data));
}
/* Auto-increment tlbmisc.WAY */
env->regs[CR_TLBMISC] =
(env->regs[CR_TLBMISC] & ~CR_TLBMISC_WAY_MASK) |
(((way + 1) & (cpu->tlb_num_ways - 1)) <<
CR_TLBMISC_WAY_SHIFT);
}
/* Writes to TLBACC don't change the read-back value */
env->mmu.tlbacc_wr = v;
break;
case CR_TLBMISC:
MMU_LOG(qemu_log("TLBMISC: WAY %X, FLAGS %c%c%c%c%c%c, PID %04X\n",
v >> CR_TLBMISC_WAY_SHIFT,
(v & CR_TLBMISC_RD) ? 'R' : '.',
(v & CR_TLBMISC_WR) ? 'W' : '.',
(v & CR_TLBMISC_DBL) ? '2' : '.',
(v & CR_TLBMISC_BAD) ? 'B' : '.',
(v & CR_TLBMISC_PERM) ? 'P' : '.',
(v & CR_TLBMISC_D) ? 'D' : '.',
(v & CR_TLBMISC_PID_MASK) >> 4));
if ((v & CR_TLBMISC_PID_MASK) !=
(env->mmu.tlbmisc_wr & CR_TLBMISC_PID_MASK)) {
mmu_flush_pid(env, (env->mmu.tlbmisc_wr & CR_TLBMISC_PID_MASK) >>
CR_TLBMISC_PID_SHIFT);
}
/* if tlbmisc.RD == 1 then trigger a TLB read on writes to TLBMISC */
if (v & CR_TLBMISC_RD) {
int way = (v >> CR_TLBMISC_WAY_SHIFT);
int vpn = (env->mmu.pteaddr_wr & CR_PTEADDR_VPN_MASK) >> 2;
Nios2TLBEntry *entry =
&env->mmu.tlb[(way * cpu->tlb_num_ways) +
(vpn & env->mmu.tlb_entry_mask)];
env->regs[CR_TLBACC] &= CR_TLBACC_IGN_MASK;
env->regs[CR_TLBACC] |= entry->data;
env->regs[CR_TLBACC] |= (entry->tag & (1 << 11)) ? CR_TLBACC_G : 0;
env->regs[CR_TLBMISC] =
(v & ~CR_TLBMISC_PID_MASK) |
((entry->tag & ((1 << cpu->pid_num_bits) - 1)) <<
CR_TLBMISC_PID_SHIFT);
env->regs[CR_PTEADDR] &= ~CR_PTEADDR_VPN_MASK;
env->regs[CR_PTEADDR] |= (entry->tag >> 12) << CR_PTEADDR_VPN_SHIFT;
MMU_LOG(qemu_log("TLB READ way %d, vpn %05X, tag %08X, data %08X, "
"tlbacc %08X, tlbmisc %08X, pteaddr %08X\n",
way, vpn, entry->tag, entry->data,
env->regs[CR_TLBACC], env->regs[CR_TLBMISC],
env->regs[CR_PTEADDR]));
} else {
env->regs[CR_TLBMISC] = v;
}
env->mmu.tlbmisc_wr = v;
break;
case CR_PTEADDR:
MMU_LOG(qemu_log("PTEADDR: PTBASE %03X, VPN %05X\n",
v >> CR_PTEADDR_PTBASE_SHIFT,
(v & CR_PTEADDR_VPN_MASK) >> CR_PTEADDR_VPN_SHIFT));
/* Writes to PTEADDR don't change the read-back VPN value */
env->regs[CR_PTEADDR] = (v & ~CR_PTEADDR_VPN_MASK) |
(env->regs[CR_PTEADDR] & CR_PTEADDR_VPN_MASK);
env->mmu.pteaddr_wr = v;
break;
default:
break;
}
}
void mmu_init(CPUNios2State *env)
{
Nios2CPU *cpu = env_archcpu(env);
Nios2MMU *mmu = &env->mmu;
MMU_LOG(qemu_log("mmu_init\n"));
mmu->tlb_entry_mask = (cpu->tlb_num_entries / cpu->tlb_num_ways) - 1;
mmu->tlb = g_new0(Nios2TLBEntry, cpu->tlb_num_entries);
}
void dump_mmu(CPUNios2State *env)
{
Nios2CPU *cpu = env_archcpu(env);
int i;
qemu_printf("MMU: ways %d, entries %d, pid bits %d\n",
cpu->tlb_num_ways, cpu->tlb_num_entries,
cpu->pid_num_bits);
for (i = 0; i < cpu->tlb_num_entries; i++) {
Nios2TLBEntry *entry = &env->mmu.tlb[i];
qemu_printf("TLB[%d] = %08X %08X %c VPN %05X "
"PID %02X %c PFN %05X %c%c%c%c\n",
i, entry->tag, entry->data,
(entry->tag & (1 << 10)) ? 'V' : '-',
entry->tag >> 12,
entry->tag & ((1 << cpu->pid_num_bits) - 1),
(entry->tag & (1 << 11)) ? 'G' : '-',
entry->data & CR_TLBACC_PFN_MASK,
(entry->data & CR_TLBACC_C) ? 'C' : '-',
(entry->data & CR_TLBACC_R) ? 'R' : '-',
(entry->data & CR_TLBACC_W) ? 'W' : '-',
(entry->data & CR_TLBACC_X) ? 'X' : '-');
}
}
#endif /* !CONFIG_USER_ONLY */
