hw/grlib_apbuart.c

   1 /*
   2  * QEMU GRLIB APB UART Emulator
   3  *
   4  * Copyright (c) 2010-2011 AdaCore
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "sysbus.h"
  26 #include "qemu-char.h"
  27 #include "ptimer.h"
  28
  29 #include "trace.h"
  30
  31 #define UART_REG_SIZE 20     /* Size of memory mapped registers */
  32
  33 /* UART status register fields */
  34 #define UART_DATA_READY           (1 <<  0)
  35 #define UART_TRANSMIT_SHIFT_EMPTY (1 <<  1)
  36 #define UART_TRANSMIT_FIFO_EMPTY  (1 <<  2)
  37 #define UART_BREAK_RECEIVED       (1 <<  3)
  38 #define UART_OVERRUN              (1 <<  4)
  39 #define UART_PARITY_ERROR         (1 <<  5)
  40 #define UART_FRAMING_ERROR        (1 <<  6)
  41 #define UART_TRANSMIT_FIFO_HALF   (1 <<  7)
  42 #define UART_RECEIVE_FIFO_HALF    (1 <<  8)
  43 #define UART_TRANSMIT_FIFO_FULL   (1 <<  9)
  44 #define UART_RECEIVE_FIFO_FULL    (1 << 10)
  45
  46 /* UART control register fields */
  47 #define UART_RECEIVE_ENABLE          (1 <<  0)
  48 #define UART_TRANSMIT_ENABLE         (1 <<  1)
  49 #define UART_RECEIVE_INTERRUPT       (1 <<  2)
  50 #define UART_TRANSMIT_INTERRUPT      (1 <<  3)
  51 #define UART_PARITY_SELECT           (1 <<  4)
  52 #define UART_PARITY_ENABLE           (1 <<  5)
  53 #define UART_FLOW_CONTROL            (1 <<  6)
  54 #define UART_LOOPBACK                (1 <<  7)
  55 #define UART_EXTERNAL_CLOCK          (1 <<  8)
  56 #define UART_RECEIVE_FIFO_INTERRUPT  (1 <<  9)
  57 #define UART_TRANSMIT_FIFO_INTERRUPT (1 << 10)
  58 #define UART_FIFO_DEBUG_MODE         (1 << 11)
  59 #define UART_OUTPUT_ENABLE           (1 << 12)
  60 #define UART_FIFO_AVAILABLE          (1 << 31)
  61
  62 /* Memory mapped register offsets */
  63 #define DATA_OFFSET       0x00
  64 #define STATUS_OFFSET     0x04
  65 #define CONTROL_OFFSET    0x08
  66 #define SCALER_OFFSET     0x0C  /* not supported */
  67 #define FIFO_DEBUG_OFFSET 0x10  /* not supported */
  68
  69 typedef struct UART {
  70     SysBusDevice busdev;
  71     MemoryRegion iomem;
  72     qemu_irq irq;
  73
  74     CharDriverState *chr;
  75
  76     /* registers */
  77     uint32_t receive;
  78     uint32_t status;
  79     uint32_t control;
  80 } UART;
  81
  82 static int grlib_apbuart_can_receive(void *opaque)
  83 {
  84     UART *uart = opaque;
  85
  86     return !!(uart->status & UART_DATA_READY);
  87 }
  88
  89 static void grlib_apbuart_receive(void *opaque, const uint8_t *buf, int size)
  90 {
  91     UART *uart = opaque;
  92
  93     uart->receive  = *buf;
  94     uart->status  |= UART_DATA_READY;
  95
  96     if (uart->control & UART_RECEIVE_INTERRUPT) {
  97         qemu_irq_pulse(uart->irq);
  98     }
  99 }
 100
 101 static void grlib_apbuart_event(void *opaque, int event)
 102 {
 103     trace_grlib_apbuart_event(event);
 104 }
 105
 106 static void
 107 grlib_apbuart_write(void *opaque, target_phys_addr_t addr,
 108                     uint64_t value, unsigned size)
 109 {
 110     UART          *uart = opaque;
 111     unsigned char  c    = 0;
 112
 113     addr &= 0xff;
 114
 115     /* Unit registers */
 116     switch (addr) {
 117     case DATA_OFFSET:
 118         c = value & 0xFF;
 119         qemu_chr_fe_write(uart->chr, &c, 1);
 120         return;
 121
 122     case STATUS_OFFSET:
 123         /* Read Only */
 124         return;
 125
 126     case CONTROL_OFFSET:
 127         /* Not supported */
 128         return;
 129
 130     case SCALER_OFFSET:
 131         /* Not supported */
 132         return;
 133
 134     default:
 135         break;
 136     }
 137
 138     trace_grlib_apbuart_writel_unknown(addr, value);
 139 }
 140
 141 static bool grlib_apbuart_accepts(void *opaque, target_phys_addr_t addr,
 142                                   unsigned size, bool is_write)
 143 {
 144     return is_write && size == 4;
 145 }
 146
 147 static const MemoryRegionOps grlib_apbuart_ops = {
 148     .write = grlib_apbuart_write,
 149     .valid.accepts = grlib_apbuart_accepts,
 150     .endianness = DEVICE_NATIVE_ENDIAN,
 151 };
 152
 153 static int grlib_apbuart_init(SysBusDevice *dev)
 154 {
 155     UART *uart      = FROM_SYSBUS(typeof(*uart), dev);
 156
 157     qemu_chr_add_handlers(uart->chr,
 158                           grlib_apbuart_can_receive,
 159                           grlib_apbuart_receive,
 160                           grlib_apbuart_event,
 161                           uart);
 162
 163     sysbus_init_irq(dev, &uart->irq);
 164
 165     memory_region_init_io(&uart->iomem, &grlib_apbuart_ops, uart,
 166                           "uart", UART_REG_SIZE);
 167
 168     sysbus_init_mmio(dev, &uart->iomem);
 169
 170     return 0;
 171 }
 172
 173 static SysBusDeviceInfo grlib_gptimer_info = {
 174     .init       = grlib_apbuart_init,
 175     .qdev.name  = "grlib,apbuart",
 176     .qdev.size  = sizeof(UART),
 177     .qdev.props = (Property[]) {
 178         DEFINE_PROP_CHR("chrdev", UART, chr),
 179         DEFINE_PROP_END_OF_LIST()
 180     }
 181 };
 182
 183 static void grlib_gptimer_register(void)
 184 {
 185     sysbus_register_withprop(&grlib_gptimer_info);
 186 }
 187
 188 device_init(grlib_gptimer_register)