qemu/include/hw/char/avr_usart.h
Michael Rolnik 429ca9d665 hw/char: avr: Add limited support for USART peripheral
These were designed to facilitate testing but should provide enough
function to be useful in other contexts.  Only a subset of the functions
of each peripheral is implemented, mainly due to the lack of a standard
way to handle electrical connections (like GPIO pins).

[AM: Remove word 'Atmel' from filenames and all elements of code]
Suggested-by: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
Signed-off-by: Sarah Harris <S.E.Harris@kent.ac.uk>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
[rth: Squash I/O size fix and file rename from f4bug]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
Reviewed-by: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>
Message-Id: <20200705140315.260514-20-huth@tuxfamily.org>
2020-07-11 11:02:05 +02:00

94 lines
2.4 KiB
C

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