311 lines
7.0 KiB
C
311 lines
7.0 KiB
C
/*
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* QEMU model of the LatticeMico32 UART block.
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*
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* Copyright (c) 2010 Michael Walle <michael@walle.cc>
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*
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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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*
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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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*
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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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*
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*
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* Specification available at:
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* http://www.latticesemi.com/documents/mico32uart.pdf
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*/
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#include "qemu/osdep.h"
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#include "hw/hw.h"
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#include "hw/sysbus.h"
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#include "trace.h"
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#include "chardev/char-fe.h"
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#include "qemu/error-report.h"
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enum {
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R_RXTX = 0,
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R_IER,
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R_IIR,
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R_LCR,
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R_MCR,
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R_LSR,
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R_MSR,
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R_DIV,
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R_MAX
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};
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enum {
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IER_RBRI = (1<<0),
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IER_THRI = (1<<1),
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IER_RLSI = (1<<2),
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IER_MSI = (1<<3),
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};
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enum {
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IIR_STAT = (1<<0),
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IIR_ID0 = (1<<1),
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IIR_ID1 = (1<<2),
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};
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enum {
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LCR_WLS0 = (1<<0),
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LCR_WLS1 = (1<<1),
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LCR_STB = (1<<2),
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LCR_PEN = (1<<3),
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LCR_EPS = (1<<4),
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LCR_SP = (1<<5),
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LCR_SB = (1<<6),
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};
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enum {
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MCR_DTR = (1<<0),
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MCR_RTS = (1<<1),
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};
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enum {
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LSR_DR = (1<<0),
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LSR_OE = (1<<1),
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LSR_PE = (1<<2),
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LSR_FE = (1<<3),
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LSR_BI = (1<<4),
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LSR_THRE = (1<<5),
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LSR_TEMT = (1<<6),
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};
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enum {
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MSR_DCTS = (1<<0),
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MSR_DDSR = (1<<1),
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MSR_TERI = (1<<2),
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MSR_DDCD = (1<<3),
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MSR_CTS = (1<<4),
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MSR_DSR = (1<<5),
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MSR_RI = (1<<6),
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MSR_DCD = (1<<7),
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};
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#define TYPE_LM32_UART "lm32-uart"
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#define LM32_UART(obj) OBJECT_CHECK(LM32UartState, (obj), TYPE_LM32_UART)
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struct LM32UartState {
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SysBusDevice parent_obj;
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MemoryRegion iomem;
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CharBackend chr;
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qemu_irq irq;
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uint32_t regs[R_MAX];
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};
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typedef struct LM32UartState LM32UartState;
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static void uart_update_irq(LM32UartState *s)
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{
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unsigned int irq;
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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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irq = 1;
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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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irq = 1;
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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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irq = 1;
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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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irq = 1;
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s->regs[R_IIR] = 0;
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} else {
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irq = 0;
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s->regs[R_IIR] = IIR_STAT;
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}
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trace_lm32_uart_irq_state(irq);
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qemu_set_irq(s->irq, irq);
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}
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static uint64_t uart_read(void *opaque, hwaddr addr,
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unsigned size)
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{
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LM32UartState *s = opaque;
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uint32_t r = 0;
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addr >>= 2;
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switch (addr) {
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case R_RXTX:
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r = s->regs[R_RXTX];
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s->regs[R_LSR] &= ~LSR_DR;
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uart_update_irq(s);
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qemu_chr_fe_accept_input(&s->chr);
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break;
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case R_IIR:
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case R_LSR:
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case R_MSR:
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r = s->regs[addr];
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break;
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case R_IER:
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case R_LCR:
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case R_MCR:
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case R_DIV:
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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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break;
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default:
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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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break;
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}
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trace_lm32_uart_memory_read(addr << 2, r);
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return r;
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}
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static void uart_write(void *opaque, hwaddr addr,
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uint64_t value, unsigned size)
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{
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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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addr >>= 2;
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switch (addr) {
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case R_RXTX:
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/* XXX this blocks entire thread. Rewrite to use
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* qemu_chr_fe_write and background I/O callbacks */
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qemu_chr_fe_write_all(&s->chr, &ch, 1);
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break;
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case R_IER:
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case R_LCR:
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case R_MCR:
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case R_DIV:
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s->regs[addr] = value;
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break;
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case R_IIR:
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case R_LSR:
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case R_MSR:
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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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break;
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default:
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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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break;
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}
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uart_update_irq(s);
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}
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static const MemoryRegionOps uart_ops = {
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.read = uart_read,
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.write = uart_write,
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.endianness = DEVICE_NATIVE_ENDIAN,
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.valid = {
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.min_access_size = 4,
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.max_access_size = 4,
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},
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};
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static void uart_rx(void *opaque, const uint8_t *buf, int size)
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{
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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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}
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s->regs[R_LSR] |= LSR_DR;
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s->regs[R_RXTX] = *buf;
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uart_update_irq(s);
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}
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static int uart_can_rx(void *opaque)
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{
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LM32UartState *s = opaque;
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return !(s->regs[R_LSR] & LSR_DR);
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}
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static void uart_event(void *opaque, int event)
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{
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}
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static void uart_reset(DeviceState *d)
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{
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LM32UartState *s = LM32_UART(d);
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int i;
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for (i = 0; i < R_MAX; i++) {
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s->regs[i] = 0;
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}
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/* defaults */
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s->regs[R_LSR] = LSR_THRE | LSR_TEMT;
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}
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static void lm32_uart_init(Object *obj)
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{
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LM32UartState *s = LM32_UART(obj);
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SysBusDevice *dev = SYS_BUS_DEVICE(obj);
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sysbus_init_irq(dev, &s->irq);
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memory_region_init_io(&s->iomem, obj, &uart_ops, s,
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"uart", R_MAX * 4);
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sysbus_init_mmio(dev, &s->iomem);
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}
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static void lm32_uart_realize(DeviceState *dev, Error **errp)
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{
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LM32UartState *s = LM32_UART(dev);
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qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
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uart_event, NULL, s, NULL, true);
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}
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static const VMStateDescription vmstate_lm32_uart = {
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.name = "lm32-uart",
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.version_id = 1,
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.minimum_version_id = 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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}
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};
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static Property lm32_uart_properties[] = {
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DEFINE_PROP_CHR("chardev", LM32UartState, chr),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void lm32_uart_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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dc->reset = uart_reset;
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dc->vmsd = &vmstate_lm32_uart;
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dc->props = lm32_uart_properties;
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dc->realize = lm32_uart_realize;
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}
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static const TypeInfo lm32_uart_info = {
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.name = TYPE_LM32_UART,
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.parent = TYPE_SYS_BUS_DEVICE,
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.instance_size = sizeof(LM32UartState),
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.instance_init = lm32_uart_init,
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.class_init = lm32_uart_class_init,
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};
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static void lm32_uart_register_types(void)
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{
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type_register_static(&lm32_uart_info);
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}
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type_init(lm32_uart_register_types)
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