hw/char/stm32f2xx_usart.c

   1 /*
   2  * STM32F2XX USART
   3  *
   4  * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
   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 "hw/char/stm32f2xx_usart.h"
  26
  27 #ifndef STM_USART_ERR_DEBUG
  28 #define STM_USART_ERR_DEBUG 0
  29 #endif
  30
  31 #define DB_PRINT_L(lvl, fmt, args...) do { \
  32     if (STM_USART_ERR_DEBUG >= lvl) { \
  33         qemu_log("%s: " fmt, __func__, ## args); \
  34     } \
  35 } while (0);
  36
  37 #define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
  38
  39 static int stm32f2xx_usart_can_receive(void *opaque)
  40 {
  41     STM32F2XXUsartState *s = opaque;
  42
  43     if (!(s->usart_sr & USART_SR_RXNE)) {
  44         return 1;
  45     }
  46
  47     return 0;
  48 }
  49
  50 static void stm32f2xx_usart_receive(void *opaque, const uint8_t *buf, int size)
  51 {
  52     STM32F2XXUsartState *s = opaque;
  53
  54     s->usart_dr = *buf;
  55
  56     if (!(s->usart_cr1 & USART_CR1_UE && s->usart_cr1 & USART_CR1_RE)) {
  57         /* USART not enabled - drop the chars */
  58         DB_PRINT("Dropping the chars\n");
  59         return;
  60     }
  61
  62     s->usart_sr |= USART_SR_RXNE;
  63
  64     if (s->usart_cr1 & USART_CR1_RXNEIE) {
  65         qemu_set_irq(s->irq, 1);
  66     }
  67
  68     DB_PRINT("Receiving: %c\n", s->usart_dr);
  69 }
  70
  71 static void stm32f2xx_usart_reset(DeviceState *dev)
  72 {
  73     STM32F2XXUsartState *s = STM32F2XX_USART(dev);
  74
  75     s->usart_sr = USART_SR_RESET;
  76     s->usart_dr = 0x00000000;
  77     s->usart_brr = 0x00000000;
  78     s->usart_cr1 = 0x00000000;
  79     s->usart_cr2 = 0x00000000;
  80     s->usart_cr3 = 0x00000000;
  81     s->usart_gtpr = 0x00000000;
  82
  83     qemu_set_irq(s->irq, 0);
  84 }
  85
  86 static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
  87                                        unsigned int size)
  88 {
  89     STM32F2XXUsartState *s = opaque;
  90     uint64_t retvalue;
  91
  92     DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);
  93
  94     switch (addr) {
  95     case USART_SR:
  96         retvalue = s->usart_sr;
  97         s->usart_sr &= ~USART_SR_TC;
  98         if (s->chr) {
  99             qemu_chr_accept_input(s->chr);
 100         }
 101         return retvalue;
 102     case USART_DR:
 103         DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
 104         s->usart_sr |= USART_SR_TXE;
 105         s->usart_sr &= ~USART_SR_RXNE;
 106         if (s->chr) {
 107             qemu_chr_accept_input(s->chr);
 108         }
 109         qemu_set_irq(s->irq, 0);
 110         return s->usart_dr & 0x3FF;
 111     case USART_BRR:
 112         return s->usart_brr;
 113     case USART_CR1:
 114         return s->usart_cr1;
 115     case USART_CR2:
 116         return s->usart_cr2;
 117     case USART_CR3:
 118         return s->usart_cr3;
 119     case USART_GTPR:
 120         return s->usart_gtpr;
 121     default:
 122         qemu_log_mask(LOG_GUEST_ERROR,
 123                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
 124         return 0;
 125     }
 126
 127     return 0;
 128 }
 129
 130 static void stm32f2xx_usart_write(void *opaque, hwaddr addr,
 131                                   uint64_t val64, unsigned int size)
 132 {
 133     STM32F2XXUsartState *s = opaque;
 134     uint32_t value = val64;
 135     unsigned char ch;
 136
 137     DB_PRINT("Write 0x%" PRIx32 ", 0x%"HWADDR_PRIx"\n", value, addr);
 138
 139     switch (addr) {
 140     case USART_SR:
 141         if (value <= 0x3FF) {
 142             s->usart_sr = value;
 143         } else {
 144             s->usart_sr &= value;
 145         }
 146         if (!(s->usart_sr & USART_SR_RXNE)) {
 147             qemu_set_irq(s->irq, 0);
 148         }
 149         return;
 150     case USART_DR:
 151         if (value < 0xF000) {
 152             ch = value;
 153             if (s->chr) {
 154                 qemu_chr_fe_write_all(s->chr, &ch, 1);
 155             }
 156             s->usart_sr |= USART_SR_TC;
 157             s->usart_sr &= ~USART_SR_TXE;
 158         }
 159         return;
 160     case USART_BRR:
 161         s->usart_brr = value;
 162         return;
 163     case USART_CR1:
 164         s->usart_cr1 = value;
 165             if (s->usart_cr1 & USART_CR1_RXNEIE &&
 166                 s->usart_sr & USART_SR_RXNE) {
 167                 qemu_set_irq(s->irq, 1);
 168             }
 169         return;
 170     case USART_CR2:
 171         s->usart_cr2 = value;
 172         return;
 173     case USART_CR3:
 174         s->usart_cr3 = value;
 175         return;
 176     case USART_GTPR:
 177         s->usart_gtpr = value;
 178         return;
 179     default:
 180         qemu_log_mask(LOG_GUEST_ERROR,
 181                       "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
 182     }
 183 }
 184
 185 static const MemoryRegionOps stm32f2xx_usart_ops = {
 186     .read = stm32f2xx_usart_read,
 187     .write = stm32f2xx_usart_write,
 188     .endianness = DEVICE_NATIVE_ENDIAN,
 189 };
 190
 191 static void stm32f2xx_usart_init(Object *obj)
 192 {
 193     STM32F2XXUsartState *s = STM32F2XX_USART(obj);
 194
 195     sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
 196
 197     memory_region_init_io(&s->mmio, obj, &stm32f2xx_usart_ops, s,
 198                           TYPE_STM32F2XX_USART, 0x2000);
 199     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
 200
 201     /* FIXME use a qdev chardev prop instead of qemu_char_get_next_serial() */
 202     s->chr = qemu_char_get_next_serial();
 203
 204     if (s->chr) {
 205         qemu_chr_add_handlers(s->chr, stm32f2xx_usart_can_receive,
 206                               stm32f2xx_usart_receive, NULL, s);
 207     }
 208 }
 209
 210 static void stm32f2xx_usart_class_init(ObjectClass *klass, void *data)
 211 {
 212     DeviceClass *dc = DEVICE_CLASS(klass);
 213
 214     dc->reset = stm32f2xx_usart_reset;
 215     /* Reason: instance_init() method uses qemu_char_get_next_serial() */
 216     dc->cannot_instantiate_with_device_add_yet = true;
 217 }
 218
 219 static const TypeInfo stm32f2xx_usart_info = {
 220     .name          = TYPE_STM32F2XX_USART,
 221     .parent        = TYPE_SYS_BUS_DEVICE,
 222     .instance_size = sizeof(STM32F2XXUsartState),
 223     .instance_init = stm32f2xx_usart_init,
 224     .class_init    = stm32f2xx_usart_class_init,
 225 };
 226
 227 static void stm32f2xx_usart_register_types(void)
 228 {
 229     type_register_static(&stm32f2xx_usart_info);
 230 }
 231
 232 type_init(stm32f2xx_usart_register_types)