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 "qom/object.h"
  28
  29 /* Offsets of registers. */
  30 #define USART_DR   0x06
  31 #define USART_CSRA  0x00
  32 #define USART_CSRB  0x01
  33 #define USART_CSRC  0x02
  34 #define USART_BRRH 0x05
  35 #define USART_BRRL 0x04
  36
  37 /* Relevant bits in regiters. */
  38 #define USART_CSRA_RXC    (1 << 7)
  39 #define USART_CSRA_TXC    (1 << 6)
  40 #define USART_CSRA_DRE    (1 << 5)
  41 #define USART_CSRA_MPCM   (1 << 0)
  42
  43 #define USART_CSRB_RXCIE  (1 << 7)
  44 #define USART_CSRB_TXCIE  (1 << 6)
  45 #define USART_CSRB_DREIE  (1 << 5)
  46 #define USART_CSRB_RXEN   (1 << 4)
  47 #define USART_CSRB_TXEN   (1 << 3)
  48 #define USART_CSRB_CSZ2   (1 << 2)
  49 #define USART_CSRB_RXB8   (1 << 1)
  50 #define USART_CSRB_TXB8   (1 << 0)
  51
  52 #define USART_CSRC_MSEL1  (1 << 7)
  53 #define USART_CSRC_MSEL0  (1 << 6)
  54 #define USART_CSRC_PM1    (1 << 5)
  55 #define USART_CSRC_PM0    (1 << 4)
  56 #define USART_CSRC_CSZ1   (1 << 2)
  57 #define USART_CSRC_CSZ0   (1 << 1)
  58
  59 #define TYPE_AVR_USART "avr-usart"
  60 OBJECT_DECLARE_SIMPLE_TYPE(AVRUsartState, AVR_USART)
  61
  62 struct AVRUsartState {
  63     /* <private> */
  64     SysBusDevice parent_obj;
  65
  66     /* <public> */
  67     MemoryRegion mmio;
  68
  69     CharBackend chr;
  70
  71     bool enabled;
  72
  73     uint8_t data;
  74     bool data_valid;
  75     uint8_t char_mask;
  76     /* Control and Status Registers */
  77     uint8_t csra;
  78     uint8_t csrb;
  79     uint8_t csrc;
  80     /* Baud Rate Registers (low/high byte) */
  81     uint8_t brrh;
  82     uint8_t brrl;
  83
  84     /* Receive Complete */
  85     qemu_irq rxc_irq;
  86     /* Transmit Complete */
  87     qemu_irq txc_irq;
  88     /* Data Register Empty */
  89     qemu_irq dre_irq;
  90 };
  91
  92 #endif /* HW_CHAR_AVR_USART_H */