94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
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/*
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* AVR USART
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*
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* Copyright (c) 2018 University of Kent
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* Author: Sarah Harris
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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 2.1 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
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* <http://www.gnu.org/licenses/lgpl-2.1.html>
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*/
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#ifndef HW_CHAR_AVR_USART_H
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#define HW_CHAR_AVR_USART_H
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#include "hw/sysbus.h"
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#include "chardev/char-fe.h"
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#include "hw/hw.h"
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/* Offsets of registers. */
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#define USART_DR 0x06
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#define USART_CSRA 0x00
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#define USART_CSRB 0x01
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#define USART_CSRC 0x02
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#define USART_BRRH 0x05
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#define USART_BRRL 0x04
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/* Relevant bits in regiters. */
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#define USART_CSRA_RXC (1 << 7)
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#define USART_CSRA_TXC (1 << 6)
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#define USART_CSRA_DRE (1 << 5)
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#define USART_CSRA_MPCM (1 << 0)
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#define USART_CSRB_RXCIE (1 << 7)
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#define USART_CSRB_TXCIE (1 << 6)
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#define USART_CSRB_DREIE (1 << 5)
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#define USART_CSRB_RXEN (1 << 4)
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#define USART_CSRB_TXEN (1 << 3)
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#define USART_CSRB_CSZ2 (1 << 2)
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#define USART_CSRB_RXB8 (1 << 1)
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#define USART_CSRB_TXB8 (1 << 0)
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#define USART_CSRC_MSEL1 (1 << 7)
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#define USART_CSRC_MSEL0 (1 << 6)
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#define USART_CSRC_PM1 (1 << 5)
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#define USART_CSRC_PM0 (1 << 4)
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#define USART_CSRC_CSZ1 (1 << 2)
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#define USART_CSRC_CSZ0 (1 << 1)
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#define TYPE_AVR_USART "avr-usart"
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#define AVR_USART(obj) \
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OBJECT_CHECK(AVRUsartState, (obj), TYPE_AVR_USART)
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typedef struct {
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/* <private> */
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SysBusDevice parent_obj;
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/* <public> */
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MemoryRegion mmio;
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CharBackend chr;
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bool enabled;
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uint8_t data;
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bool data_valid;
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uint8_t char_mask;
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/* Control and Status Registers */
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uint8_t csra;
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uint8_t csrb;
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uint8_t csrc;
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/* Baud Rate Registers (low/high byte) */
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uint8_t brrh;
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uint8_t brrl;
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/* Receive Complete */
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qemu_irq rxc_irq;
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/* Transmit Complete */
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qemu_irq txc_irq;
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/* Data Register Empty */
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qemu_irq dre_irq;
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} AVRUsartState;
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#endif /* HW_CHAR_AVR_USART_H */
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