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* QEMU model of the LatticeMico32 UART block.
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* Copyright (c) 2010 Michael Walle <michael@walle.cc>
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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* Specification available at:
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* http://www.latticesemi.com/documents/mico32uart.pdf
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#include "qemu-char.h"
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#include "qemu-error.h"
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struct LM32UartState {
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typedef struct LM32UartState LM32UartState;
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static void uart_update_irq(LM32UartState *s)
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if ((s->regs[R_LSR] & (LSR_OE | LSR_PE | LSR_FE | LSR_BI))
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&& (s->regs[R_IER] & IER_RLSI)) {
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s->regs[R_IIR] = IIR_ID1 | IIR_ID0;
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} else if ((s->regs[R_LSR] & LSR_DR) && (s->regs[R_IER] & IER_RBRI)) {
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s->regs[R_IIR] = IIR_ID1;
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} else if ((s->regs[R_LSR] & LSR_THRE) && (s->regs[R_IER] & IER_THRI)) {
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s->regs[R_IIR] = IIR_ID0;
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} else if ((s->regs[R_MSR] & 0x0f) && (s->regs[R_IER] & IER_MSI)) {
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s->regs[R_IIR] = IIR_STAT;
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trace_lm32_uart_irq_state(irq);
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qemu_set_irq(s->irq, irq);
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static uint32_t uart_read(void *opaque, target_phys_addr_t addr)
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LM32UartState *s = opaque;
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s->regs[R_LSR] &= ~LSR_DR;
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error_report("lm32_uart: read access to write only register 0x"
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TARGET_FMT_plx, addr << 2);
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error_report("lm32_uart: read access to unknown register 0x"
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TARGET_FMT_plx, addr << 2);
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trace_lm32_uart_memory_read(addr << 2, r);
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static void uart_write(void *opaque, target_phys_addr_t addr, uint32_t value)
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LM32UartState *s = opaque;
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unsigned char ch = value;
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trace_lm32_uart_memory_write(addr, value);
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qemu_chr_fe_write(s->chr, &ch, 1);
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s->regs[addr] = value;
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error_report("lm32_uart: write access to read only register 0x"
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TARGET_FMT_plx, addr << 2);
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error_report("lm32_uart: write access to unknown register 0x"
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TARGET_FMT_plx, addr << 2);
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static CPUReadMemoryFunc * const uart_read_fn[] = {
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static CPUWriteMemoryFunc * const uart_write_fn[] = {
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static void uart_rx(void *opaque, const uint8_t *buf, int size)
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LM32UartState *s = opaque;
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if (s->regs[R_LSR] & LSR_DR) {
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s->regs[R_LSR] |= LSR_OE;
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s->regs[R_LSR] |= LSR_DR;
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s->regs[R_RXTX] = *buf;
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static int uart_can_rx(void *opaque)
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LM32UartState *s = opaque;
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return !(s->regs[R_LSR] & LSR_DR);
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static void uart_event(void *opaque, int event)
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static void uart_reset(DeviceState *d)
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LM32UartState *s = container_of(d, LM32UartState, busdev.qdev);
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for (i = 0; i < R_MAX; i++) {
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s->regs[R_LSR] = LSR_THRE | LSR_TEMT;
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static int lm32_uart_init(SysBusDevice *dev)
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LM32UartState *s = FROM_SYSBUS(typeof(*s), dev);
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sysbus_init_irq(dev, &s->irq);
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uart_regs = cpu_register_io_memory(uart_read_fn, uart_write_fn, s,
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DEVICE_NATIVE_ENDIAN);
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sysbus_init_mmio(dev, R_MAX * 4, uart_regs);
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s->chr = qdev_init_chardev(&dev->qdev);
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qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s);
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static const VMStateDescription vmstate_lm32_uart = {
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.minimum_version_id = 1,
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.minimum_version_id_old = 1,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32_ARRAY(regs, LM32UartState, R_MAX),
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VMSTATE_END_OF_LIST()
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static SysBusDeviceInfo lm32_uart_info = {
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.init = lm32_uart_init,
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.qdev.name = "lm32-uart",
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.qdev.size = sizeof(LM32UartState),
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.qdev.vmsd = &vmstate_lm32_uart,
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.qdev.reset = uart_reset,
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static void lm32_uart_register(void)
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sysbus_register_withprop(&lm32_uart_info);
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device_init(lm32_uart_register)