path: root/hw/char/debugcon.c

/*
 * QEMU Bochs-style debug console ("port E9") emulation
 *
 * Copyright (c) 2003-2004 Fabrice Bellard
 * Copyright (c) 2008 Citrix Systems, Inc.
 * Copyright (c) Intel Corporation; author: H. Peter Anvin
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "chardev/char-fe.h"
#include "hw/isa/isa.h"
#include "hw/qdev-properties.h"
#include "qom/object.h"

#define TYPE_ISA_DEBUGCON_DEVICE "isa-debugcon"
OBJECT_DECLARE_SIMPLE_TYPE(ISADebugconState, ISA_DEBUGCON_DEVICE)

//#define DEBUG_DEBUGCON

typedef struct DebugconState {
    MemoryRegion io;
    CharBackend chr;
    uint32_t readback;
} DebugconState;

struct ISADebugconState {
    ISADevice parent_obj;

    uint32_t iobase;
    DebugconState state;
};

static void debugcon_ioport_write(void *opaque, hwaddr addr, uint64_t val,
                                  unsigned width)
{
    DebugconState *s = opaque;
    unsigned char ch = val;

#ifdef DEBUG_DEBUGCON
    printf(" [debugcon: write addr=0x%04" HWADDR_PRIx " val=0x%02" PRIx64 "]\n", addr, val);
#endif

    /* XXX this blocks entire thread. Rewrite to use
     * qemu_chr_fe_write and background I/O callbacks */
    qemu_chr_fe_write_all(&s->chr, &ch, 1);
}


static uint64_t debugcon_ioport_read(void *opaque, hwaddr addr, unsigned width)
{
    DebugconState *s = opaque;

#ifdef DEBUG_DEBUGCON
    printf("debugcon: read addr=0x%04" HWADDR_PRIx "\n", addr);
#endif

    return s->readback;
}

static const MemoryRegionOps debugcon_ops = {
    .read = debugcon_ioport_read,
    .write = debugcon_ioport_write,
    .valid.min_access_size = 1,
    .valid.max_access_size = 1,
    .endianness = DEVICE_LITTLE_ENDIAN,
};

static void debugcon_realize_core(DebugconState *s, Error **errp)
{
    if (!qemu_chr_fe_backend_connected(&s->chr)) {
        error_setg(errp, "Can't create debugcon device, empty char device");
        return;
    }

    qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, s, NULL, true);
}

static void debugcon_isa_realizefn(DeviceState *dev, Error **errp)
{
    ISADevice *d = ISA_DEVICE(dev);
    ISADebugconState *isa = ISA_DEBUGCON_DEVICE(dev);
    DebugconState *s = &isa->state;
    Error *err = NULL;

    debugcon_realize_core(s, &err);
    if (err != NULL) {
        error_propagate(errp, err);
        return;
    }
    memory_region_init_io(&s->io, OBJECT(dev), &debugcon_ops, s,
                          TYPE_ISA_DEBUGCON_DEVICE, 1);
    memory_region_add_subregion(isa_address_space_io(d),
                                isa->iobase, &s->io);
}

static Property debugcon_isa_properties[] = {
    DEFINE_PROP_UINT32("iobase", ISADebugconState, iobase, 0xe9),
    DEFINE_PROP_CHR("chardev",  ISADebugconState, state.chr),
    DEFINE_PROP_UINT32("readback", ISADebugconState, state.readback, 0xe9),
    DEFINE_PROP_END_OF_LIST(),
};

static void debugcon_isa_class_initfn(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);

    dc->realize = debugcon_isa_realizefn;
    device_class_set_props(dc, debugcon_isa_properties);
    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}

static const TypeInfo debugcon_isa_info = {
    .name          = TYPE_ISA_DEBUGCON_DEVICE,
    .parent        = TYPE_ISA_DEVICE,
    .instance_size = sizeof(ISADebugconState),
    .class_init    = debugcon_isa_class_initfn,
};

static void debugcon_register_types(void)
{
    type_register_static(&debugcon_isa_info);
}

type_init(debugcon_register_types)