Archipelago » qemu

/*

 * ARMV7M System emulation.

 *

 * Copyright (c) 2006-2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the GPL.

 */

#include "hw.h"

#include "arm-misc.h"

#include "sysemu.h"

/* Bitbanded IO.  Each word corresponds to a single bit.  */

/* Get the byte address of the real memory for a bitband acess.  */

static inline uint32_t bitband_addr(uint32_t addr)

{

    uint32_t res;

    res = addr & 0xe0000000;

    res |= (addr & 0x1ffffff) >> 5;

    return res;

}

static uint32_t bitband_readb(void *opaque, target_phys_addr_t offset)

{

    uint8_t v;

    cpu_physical_memory_read(bitband_addr(offset), &v, 1);

    return (v & (1 << ((offset >> 2) & 7))) != 0;

}

static void bitband_writeb(void *opaque, target_phys_addr_t offset,

                           uint32_t value)

{

    uint32_t addr;

    uint8_t mask;

    uint8_t v;

    addr = bitband_addr(offset);

    mask = (1 << ((offset >> 2) & 7));

    cpu_physical_memory_read(addr, &v, 1);

    if (value & 1)

        v |= mask;

    else

        v &= ~mask;

    cpu_physical_memory_write(addr, &v, 1);

}

static uint32_t bitband_readw(void *opaque, target_phys_addr_t offset)

{

    uint32_t addr;

    uint16_t mask;

    uint16_t v;

    addr = bitband_addr(offset) & ~1;

    mask = (1 << ((offset >> 2) & 15));

    mask = tswap16(mask);

    cpu_physical_memory_read(addr, (uint8_t *)&v, 2);

    return (v & mask) != 0;

}

static void bitband_writew(void *opaque, target_phys_addr_t offset,

                           uint32_t value)

{

    uint32_t addr;

    uint16_t mask;

    uint16_t v;

    addr = bitband_addr(offset) & ~1;

    mask = (1 << ((offset >> 2) & 15));

    mask = tswap16(mask);

    cpu_physical_memory_read(addr, (uint8_t *)&v, 2);

    if (value & 1)

        v |= mask;

    else

        v &= ~mask;

    cpu_physical_memory_write(addr, (uint8_t *)&v, 2);

}

static uint32_t bitband_readl(void *opaque, target_phys_addr_t offset)

{

    uint32_t addr;

    uint32_t mask;

    uint32_t v;

    addr = bitband_addr(offset) & ~3;

    mask = (1 << ((offset >> 2) & 31));

    mask = tswap32(mask);

    cpu_physical_memory_read(addr, (uint8_t *)&v, 4);

    return (v & mask) != 0;

}

static void bitband_writel(void *opaque, target_phys_addr_t offset,

                           uint32_t value)

{

    uint32_t addr;

    uint32_t mask;

    uint32_t v;

    addr = bitband_addr(offset) & ~3;

    mask = (1 << ((offset >> 2) & 31));

    mask = tswap32(mask);

    cpu_physical_memory_read(addr, (uint8_t *)&v, 4);

    if (value & 1)

        v |= mask;

    else

        v &= ~mask;

    cpu_physical_memory_write(addr, (uint8_t *)&v, 4);

}

static CPUReadMemoryFunc *bitband_readfn[] = {

   bitband_readb,

   bitband_readw,

   bitband_readl

};

static CPUWriteMemoryFunc *bitband_writefn[] = {

   bitband_writeb,

   bitband_writew,

   bitband_writel

};

static void armv7m_bitband_init(void)

{

    int iomemtype;

    iomemtype = cpu_register_io_memory(0, bitband_readfn, bitband_writefn,

                                       NULL);

    cpu_register_physical_memory(0x22000000, 0x02000000, iomemtype);

    cpu_register_physical_memory(0x42000000, 0x02000000, iomemtype);

}

/* Board init.  */

/* Init CPU and memory for a v7-M based board.

   flash_size and sram_size are in kb.

   Returns the NVIC array.  */

qemu_irq *armv7m_init(int flash_size, int sram_size,

                      const char *kernel_filename, const char *cpu_model)

{

    CPUState *env;

    qemu_irq *pic;

    uint32_t pc;

    int image_size;

    uint64_t entry;

    uint64_t lowaddr;

    flash_size *= 1024;

    sram_size *= 1024;

    if (!cpu_model)

        cpu_model = "cortex-m3";

    env = cpu_init(cpu_model);

    if (!env) {

        fprintf(stderr, "Unable to find CPU definition\n");

        exit(1);

    }

#if 0

    /* > 32Mb SRAM gets complicated because it overlaps the bitband area.

       We don't have proper commandline options, so allocate half of memory

       as SRAM, up to a maximum of 32Mb, and the rest as code.  */

    if (ram_size > (512 + 32) * 1024 * 1024)

        ram_size = (512 + 32) * 1024 * 1024;

    sram_size = (ram_size / 2) & TARGET_PAGE_MASK;

    if (sram_size > 32 * 1024 * 1024)

        sram_size = 32 * 1024 * 1024;

    code_size = ram_size - sram_size;

#endif

    /* Flash programming is done via the SCU, so pretend it is ROM.  */

    cpu_register_physical_memory(0, flash_size, IO_MEM_ROM);

    cpu_register_physical_memory(0x20000000, sram_size,

                                 flash_size + IO_MEM_RAM);

    armv7m_bitband_init();

    pic = armv7m_nvic_init(env);

    image_size = load_elf(kernel_filename, 0, &entry, &lowaddr, NULL);

    if (image_size < 0) {

        image_size = load_image(kernel_filename, phys_ram_base);

        lowaddr = 0;

    }

    if (image_size < 0) {

        fprintf(stderr, "qemu: could not load kernel '%s'\n",

                kernel_filename);

        exit(1);

    }

    /* If the image was loaded at address zero then assume it is a

       regular ROM image and perform the normal CPU reset sequence.

       Otherwise jump directly to the entry point.  */

    if (lowaddr == 0) {

        env->regs[13] = tswap32(*(uint32_t *)phys_ram_base);

        pc = tswap32(*(uint32_t *)(phys_ram_base + 4));

    } else {

        pc = entry;

    }

    env->thumb = pc & 1;

    env->regs[15] = pc & ~1;

    /* Hack to map an additional page of ram at the top of the address

       space.  This stops qemu complaining about executing code outside RAM

       when returning from an exception.  */

    cpu_register_physical_memory(0xfffff000, 0x1000, IO_MEM_RAM + ram_size);

    return pic;

}