Archipelago » qemu

/*

 *  QEMU model of the LatticeMico32 UART block.

 *

 *  Copyright (c) 2010 Michael Walle <michael@walle.cc>

 *

 * 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 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/>.

 *

 *

 * Specification available at:

 *   http://www.latticesemi.com/documents/mico32uart.pdf

 */

#include "hw.h"

#include "sysbus.h"

#include "trace.h"

#include "qemu-char.h"

#include "qemu-error.h"

enum {

    R_RXTX = 0,

    R_IER,

    R_IIR,

    R_LCR,

    R_MCR,

    R_LSR,

    R_MSR,

    R_DIV,

    R_MAX

};

enum {

    IER_RBRI = (1<<0),

    IER_THRI = (1<<1),

    IER_RLSI = (1<<2),

    IER_MSI  = (1<<3),

};

enum {

    IIR_STAT = (1<<0),

    IIR_ID0  = (1<<1),

    IIR_ID1  = (1<<2),

};

enum {

    LCR_WLS0 = (1<<0),

    LCR_WLS1 = (1<<1),

    LCR_STB  = (1<<2),

    LCR_PEN  = (1<<3),

    LCR_EPS  = (1<<4),

    LCR_SP   = (1<<5),

    LCR_SB   = (1<<6),

};

enum {

    MCR_DTR  = (1<<0),

    MCR_RTS  = (1<<1),

};

enum {

    LSR_DR   = (1<<0),

    LSR_OE   = (1<<1),

    LSR_PE   = (1<<2),

    LSR_FE   = (1<<3),

    LSR_BI   = (1<<4),

    LSR_THRE = (1<<5),

    LSR_TEMT = (1<<6),

};

enum {

    MSR_DCTS = (1<<0),

    MSR_DDSR = (1<<1),

    MSR_TERI = (1<<2),

    MSR_DDCD = (1<<3),

    MSR_CTS  = (1<<4),

    MSR_DSR  = (1<<5),

    MSR_RI   = (1<<6),

    MSR_DCD  = (1<<7),

};

struct LM32UartState {

    SysBusDevice busdev;

    CharDriverState *chr;

    qemu_irq irq;

    uint32_t regs[R_MAX];

};

typedef struct LM32UartState LM32UartState;

static void uart_update_irq(LM32UartState *s)

{

    unsigned int irq;

    if ((s->regs[R_LSR] & (LSR_OE | LSR_PE | LSR_FE | LSR_BI))

            && (s->regs[R_IER] & IER_RLSI)) {

        irq = 1;

        s->regs[R_IIR] = IIR_ID1 | IIR_ID0;

    } else if ((s->regs[R_LSR] & LSR_DR) && (s->regs[R_IER] & IER_RBRI)) {

        irq = 1;

        s->regs[R_IIR] = IIR_ID1;

    } else if ((s->regs[R_LSR] & LSR_THRE) && (s->regs[R_IER] & IER_THRI)) {

        irq = 1;

        s->regs[R_IIR] = IIR_ID0;

    } else if ((s->regs[R_MSR] & 0x0f) && (s->regs[R_IER] & IER_MSI)) {

        irq = 1;

        s->regs[R_IIR] = 0;

    } else {

        irq = 0;

        s->regs[R_IIR] = IIR_STAT;

    }

    trace_lm32_uart_irq_state(irq);

    qemu_set_irq(s->irq, irq);

}

static uint32_t uart_read(void *opaque, target_phys_addr_t addr)

{

    LM32UartState *s = opaque;

    uint32_t r = 0;

    addr >>= 2;

    switch (addr) {

    case R_RXTX:

        r = s->regs[R_RXTX];

        s->regs[R_LSR] &= ~LSR_DR;

        uart_update_irq(s);

        break;

    case R_IIR:

    case R_LSR:

    case R_MSR:

        r = s->regs[addr];

        break;

    case R_IER:

    case R_LCR:

    case R_MCR:

    case R_DIV:

        error_report("lm32_uart: read access to write only register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    default:

        error_report("lm32_uart: read access to unkown register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    }

    trace_lm32_uart_memory_read(addr << 2, r);

    return r;

}

static void uart_write(void *opaque, target_phys_addr_t addr, uint32_t value)

{

    LM32UartState *s = opaque;

    unsigned char ch = value;

    trace_lm32_uart_memory_write(addr, value);

    addr >>= 2;

    switch (addr) {

    case R_RXTX:

        if (s->chr) {

            qemu_chr_write(s->chr, &ch, 1);

        }

        break;

    case R_IER:

    case R_LCR:

    case R_MCR:

    case R_DIV:

        s->regs[addr] = value;

        break;

    case R_IIR:

    case R_LSR:

    case R_MSR:

        error_report("lm32_uart: write access to read only register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    default:

        error_report("lm32_uart: write access to unkown register 0x"

                TARGET_FMT_plx, addr << 2);

        break;

    }

    uart_update_irq(s);

}

static CPUReadMemoryFunc * const uart_read_fn[] = {

    NULL,

    NULL,

    &uart_read,

};

static CPUWriteMemoryFunc * const uart_write_fn[] = {

    NULL,

    NULL,

    &uart_write,

};

static void uart_rx(void *opaque, const uint8_t *buf, int size)

{

    LM32UartState *s = opaque;

    if (s->regs[R_LSR] & LSR_DR) {

        s->regs[R_LSR] |= LSR_OE;

    }

    s->regs[R_LSR] |= LSR_DR;

    s->regs[R_RXTX] = *buf;

    uart_update_irq(s);

}

static int uart_can_rx(void *opaque)

{

    LM32UartState *s = opaque;

    return !(s->regs[R_LSR] & LSR_DR);

}

static void uart_event(void *opaque, int event)

{

}

static void uart_reset(DeviceState *d)

{

    LM32UartState *s = container_of(d, LM32UartState, busdev.qdev);

    int i;

    for (i = 0; i < R_MAX; i++) {

        s->regs[i] = 0;

    }

    /* defaults */

    s->regs[R_LSR] = LSR_THRE | LSR_TEMT;

}

static int lm32_uart_init(SysBusDevice *dev)

{

    LM32UartState *s = FROM_SYSBUS(typeof(*s), dev);

    int uart_regs;

    sysbus_init_irq(dev, &s->irq);

    uart_regs = cpu_register_io_memory(uart_read_fn, uart_write_fn, s,

            DEVICE_NATIVE_ENDIAN);

    sysbus_init_mmio(dev, R_MAX * 4, uart_regs);

    s->chr = qdev_init_chardev(&dev->qdev);

    if (s->chr) {

        qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s);

    }

    return 0;

}

static const VMStateDescription vmstate_lm32_uart = {

    .name = "lm32-uart",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .fields      = (VMStateField[]) {

        VMSTATE_UINT32_ARRAY(regs, LM32UartState, R_MAX),

        VMSTATE_END_OF_LIST()

    }

};

static SysBusDeviceInfo lm32_uart_info = {

    .init = lm32_uart_init,

    .qdev.name  = "lm32-uart",

    .qdev.size  = sizeof(LM32UartState),

    .qdev.vmsd  = &vmstate_lm32_uart,

    .qdev.reset = uart_reset,

};

static void lm32_uart_register(void)

{

    sysbus_register_withprop(&lm32_uart_info);

}

device_init(lm32_uart_register)