hw/nios2/generic_nommu.c

   1 /*
   2  * Generic simulator target with no MMU or devices.  This emulation is
   3  * compatible with the libgloss qemu-hosted.ld linker script for using
   4  * QEMU as an instruction set simulator.
   5  *
   6  * Copyright (c) 2018-2019 Mentor Graphics
   7  *
   8  * Copyright (c) 2016 Marek Vasut <marek.vasut@gmail.com>
   9  *
  10  * Based on LabX device code
  11  *
  12  * Copyright (c) 2012 Chris Wulff <crwulff@gmail.com>
  13  *
  14  * This library is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU Lesser General Public
  16  * License as published by the Free Software Foundation; either
  17  * version 2.1 of the License, or (at your option) any later version.
  18  *
  19  * This library is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  * Lesser General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Lesser General Public
  25  * License along with this library; if not, see
  26  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "qapi/error.h"
  31 #include "qemu-common.h"
  32 #include "cpu.h"
  33
  34 #include "hw/sysbus.h"
  35 #include "hw/char/serial.h"
  36 #include "hw/boards.h"
  37 #include "exec/memory.h"
  38 #include "exec/address-spaces.h"
  39 #include "qemu/config-file.h"
  40
  41 #include "boot.h"
  42
  43 #define BINARY_DEVICE_TREE_FILE    "generic-nommu.dtb"
  44
  45 static void nios2_generic_nommu_init(MachineState *machine)
  46 {
  47     Nios2CPU *cpu;
  48     MemoryRegion *address_space_mem = get_system_memory();
  49     MemoryRegion *phys_tcm = g_new(MemoryRegion, 1);
  50     MemoryRegion *phys_tcm_alias = g_new(MemoryRegion, 1);
  51     MemoryRegion *phys_ram = g_new(MemoryRegion, 1);
  52     MemoryRegion *phys_ram_alias = g_new(MemoryRegion, 1);
  53     ram_addr_t tcm_base = 0x0;
  54     ram_addr_t tcm_size = 0x1000;    /* 1 kiB, but QEMU limit is 4 kiB */
  55     ram_addr_t ram_base = 0x10000000;
  56     ram_addr_t ram_size = 0x08000000;
  57
  58     /* Physical TCM (tb_ram_1k) with alias at 0xc0000000 */
  59     memory_region_init_ram(phys_tcm, NULL, "nios2.tcm", tcm_size,
  60                            &error_abort);
  61     memory_region_init_alias(phys_tcm_alias, NULL, "nios2.tcm.alias",
  62                              phys_tcm, 0, tcm_size);
  63     memory_region_add_subregion(address_space_mem, tcm_base, phys_tcm);
  64     memory_region_add_subregion(address_space_mem, 0xc0000000 + tcm_base,
  65                                 phys_tcm_alias);
  66
  67     /* Physical DRAM with alias at 0xc0000000 */
  68     memory_region_init_ram(phys_ram, NULL, "nios2.ram", ram_size,
  69                            &error_abort);
  70     memory_region_init_alias(phys_ram_alias, NULL, "nios2.ram.alias",
  71                              phys_ram, 0, ram_size);
  72     memory_region_add_subregion(address_space_mem, ram_base, phys_ram);
  73     memory_region_add_subregion(address_space_mem, 0xc0000000 + ram_base,
  74                                 phys_ram_alias);
  75
  76     cpu = NIOS2_CPU(cpu_create(TYPE_NIOS2_CPU));
  77
  78     /* Remove MMU */
  79     cpu->mmu_present = false;
  80
  81     /* Reset vector is the first 32 bytes of RAM.  */
  82     cpu->reset_addr = ram_base;
  83
  84     /* The interrupt vector comes right after reset.  */
  85     cpu->exception_addr = ram_base + 0x20;
  86
  87     /*
  88      * The linker script does have a TLB miss memory region declared,
  89      * but this should never be used with no MMU.
  90      */
  91     cpu->fast_tlb_miss_addr = 0x7fff400;
  92
  93     nios2_load_kernel(cpu, ram_base, ram_size, machine->initrd_filename,
  94                       BINARY_DEVICE_TREE_FILE, NULL);
  95 }
  96
  97 static void nios2_generic_nommu_machine_init(struct MachineClass *mc)
  98 {
  99     mc->desc = "Generic NOMMU Nios II design";
 100     mc->init = nios2_generic_nommu_init;
 101 }
 102
 103 DEFINE_MACHINE("nios2-generic-nommu", nios2_generic_nommu_machine_init);