/* * 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/hw.h" #include "hw/sysbus.h" #include "trace.h" #include "char/char.h" #include "qemu/error-report.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; MemoryRegion iomem; 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 uint64_t uart_read(void *opaque, hwaddr addr, unsigned size) { 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); qemu_chr_accept_input(s->chr); 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 unknown register 0x" TARGET_FMT_plx, addr << 2); break; } trace_lm32_uart_memory_read(addr << 2, r); return r; } static void uart_write(void *opaque, hwaddr addr, uint64_t value, unsigned size) { 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_fe_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 unknown register 0x" TARGET_FMT_plx, addr << 2); break; } uart_update_irq(s); } static const MemoryRegionOps uart_ops = { .read = uart_read, .write = uart_write, .endianness = DEVICE_NATIVE_ENDIAN, .valid = { .min_access_size = 4, .max_access_size = 4, }, }; 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); sysbus_init_irq(dev, &s->irq); memory_region_init_io(&s->iomem, &uart_ops, s, "uart", R_MAX * 4); sysbus_init_mmio(dev, &s->iomem); s->chr = qemu_char_get_next_serial(); 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 void lm32_uart_class_init(ObjectClass *klass, void *data) { DeviceClass *dc = DEVICE_CLASS(klass); SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass); k->init = lm32_uart_init; dc->reset = uart_reset; dc->vmsd = &vmstate_lm32_uart; } static const TypeInfo lm32_uart_info = { .name = "lm32-uart", .parent = TYPE_SYS_BUS_DEVICE, .instance_size = sizeof(LM32UartState), .class_init = lm32_uart_class_init, }; static void lm32_uart_register_types(void) { type_register_static(&lm32_uart_info); } type_init(lm32_uart_register_types)