include/hw/char/avr_usart.h

   1 /*
   2  * AVR USART
   3  *
   4  * Copyright (c) 2018 University of Kent
   5  * Author: Sarah Harris
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, see
  19  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  20  */
  21
  22 #ifndef HW_CHAR_AVR_USART_H
  23 #define HW_CHAR_AVR_USART_H
  24
  25 #include "hw/sysbus.h"
  26 #include "chardev/char-fe.h"
  27 #include "hw/hw.h"
  28 #include "qom/object.h"
  29
  30 /* Offsets of registers. */
  31 #define USART_DR   0x06
  32 #define USART_CSRA  0x00
  33 #define USART_CSRB  0x01
  34 #define USART_CSRC  0x02
  35 #define USART_BRRH 0x05
  36 #define USART_BRRL 0x04
  37
  38 /* Relevant bits in regiters. */
  39 #define USART_CSRA_RXC    (1 << 7)
  40 #define USART_CSRA_TXC    (1 << 6)
  41 #define USART_CSRA_DRE    (1 << 5)
  42 #define USART_CSRA_MPCM   (1 << 0)
  43
  44 #define USART_CSRB_RXCIE  (1 << 7)
  45 #define USART_CSRB_TXCIE  (1 << 6)
  46 #define USART_CSRB_DREIE  (1 << 5)
  47 #define USART_CSRB_RXEN   (1 << 4)
  48 #define USART_CSRB_TXEN   (1 << 3)
  49 #define USART_CSRB_CSZ2   (1 << 2)
  50 #define USART_CSRB_RXB8   (1 << 1)
  51 #define USART_CSRB_TXB8   (1 << 0)
  52
  53 #define USART_CSRC_MSEL1  (1 << 7)
  54 #define USART_CSRC_MSEL0  (1 << 6)
  55 #define USART_CSRC_PM1    (1 << 5)
  56 #define USART_CSRC_PM0    (1 << 4)
  57 #define USART_CSRC_CSZ1   (1 << 2)
  58 #define USART_CSRC_CSZ0   (1 << 1)
  59
  60 #define TYPE_AVR_USART "avr-usart"
  61 typedef struct AVRUsartState AVRUsartState;
  62 #define AVR_USART(obj) \
  63     OBJECT_CHECK(AVRUsartState, (obj), TYPE_AVR_USART)
  64
  65 struct AVRUsartState {
  66     /* <private> */
  67     SysBusDevice parent_obj;
  68
  69     /* <public> */
  70     MemoryRegion mmio;
  71
  72     CharBackend chr;
  73
  74     bool enabled;
  75
  76     uint8_t data;
  77     bool data_valid;
  78     uint8_t char_mask;
  79     /* Control and Status Registers */
  80     uint8_t csra;
  81     uint8_t csrb;
  82     uint8_t csrc;
  83     /* Baud Rate Registers (low/high byte) */
  84     uint8_t brrh;
  85     uint8_t brrl;
  86
  87     /* Receive Complete */
  88     qemu_irq rxc_irq;
  89     /* Transmit Complete */
  90     qemu_irq txc_irq;
  91     /* Data Register Empty */
  92     qemu_irq dre_irq;
  93 };
  94
  95 #endif /* HW_CHAR_AVR_USART_H */