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   1 /*
   2  * Copyright © 2016 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #include <ao.h>
  16 #include <ao_exti.h>
  17
  18 void
  19 ao_debug_out(char c)
  20 {
  21         if (c == '\n')
  22                 ao_debug_out('\r');
  23         while (!(stm_usart1.isr & (1 << STM_USART_ISR_TXE)));
  24         stm_usart1.tdr = c;
  25 }
  26
  27 static int
  28 _ao_usart_tx_start(struct ao_stm_usart *usart)
  29 {
  30         if (!ao_fifo_empty(usart->tx_fifo)) {
  31 #if HAS_SERIAL_SW_FLOW
  32                 if (usart->gpio_cts && ao_gpio_get(usart->gpio_cts, usart->pin_cts, foo) == 1) {
  33                         ao_exti_enable(usart->gpio_cts, usart->pin_cts);
  34                         return 0;
  35                 }
  36 #endif
  37                 if (usart->reg->isr & (1 << STM_USART_ISR_TXE))
  38                 {
  39                         usart->tx_running = 1;
  40                         usart->reg->cr1 |= (1 << STM_USART_CR1_TXEIE) | (1 << STM_USART_CR1_TCIE);
  41                         ao_fifo_remove(usart->tx_fifo, usart->reg->tdr);
  42                         ao_wakeup(&usart->tx_fifo);
  43                         return 1;
  44                 }
  45         }
  46         return 0;
  47 }
  48
  49 #if HAS_SERIAL_SW_FLOW
  50 static void
  51 _ao_usart_cts(struct ao_stm_usart *usart)
  52 {
  53         if (_ao_usart_tx_start(usart))
  54                 ao_exti_disable(usart->gpio_cts, usart->pin_cts);
  55 }
  56 #endif
  57
  58 static void
  59 _ao_usart_rx(struct ao_stm_usart *usart, int is_stdin)
  60 {
  61         if (usart->reg->isr & (1 << STM_USART_ISR_RXNE)) {
  62                 usart->reg->icr = (1 << STM_USART_ICR_ORECF);
  63                 if (!ao_fifo_full(usart->rx_fifo)) {
  64                         ao_fifo_insert(usart->rx_fifo, usart->reg->rdr);
  65                         ao_wakeup(&usart->rx_fifo);
  66                         if (is_stdin)
  67                                 ao_wakeup(&ao_stdin_ready);
  68 #if HAS_SERIAL_SW_FLOW
  69                         /* If the fifo is nearly full, turn off RTS and wait
  70                          * for it to drain a bunch
  71                          */
  72                         if (usart->gpio_rts && ao_fifo_mostly(usart->rx_fifo)) {
  73                                 ao_gpio_set(usart->gpio_rts, usart->pin_rts, usart->pin_rts, 1);
  74                                 usart->rts = 0;
  75                         }
  76 #endif
  77                 } else {
  78                         usart->reg->cr1 &= ~(1 << STM_USART_CR1_RXNEIE);
  79                 }
  80         }
  81 }
  82
  83 static void
  84 ao_usart_isr(struct ao_stm_usart *usart, int is_stdin)
  85 {
  86         _ao_usart_rx(usart, is_stdin);
  87
  88         if (!_ao_usart_tx_start(usart))
  89                 usart->reg->cr1 &= ~(1<< STM_USART_CR1_TXEIE);
  90
  91         if (usart->reg->isr & (1 << STM_USART_ISR_TC)) {
  92                 usart->tx_running = 0;
  93                 usart->reg->cr1 &= ~(1 << STM_USART_CR1_TCIE);
  94                 if (usart->draining) {
  95                         usart->draining = 0;
  96                         ao_wakeup(&usart->tx_fifo);
  97                 }
  98         }
  99 }
 100
 101 static int
 102 _ao_usart_pollchar(struct ao_stm_usart *usart)
 103 {
 104         int     c;
 105
 106         if (ao_fifo_empty(usart->rx_fifo))
 107                 c = AO_READ_AGAIN;
 108         else {
 109                 uint8_t u;
 110                 ao_fifo_remove(usart->rx_fifo,u);
 111                 if ((usart->reg->cr1 & (1 << STM_USART_CR1_RXNEIE)) == 0) {
 112                         if (ao_fifo_barely(usart->rx_fifo))
 113                                 usart->reg->cr1 |= (1 << STM_USART_CR1_RXNEIE);
 114                 }
 115 #if HAS_SERIAL_SW_FLOW
 116                 /* If we've cleared RTS, check if there's space now and turn it back on */
 117                 if (usart->gpio_rts && usart->rts == 0 && ao_fifo_barely(usart->rx_fifo)) {
 118                         ao_gpio_set(usart->gpio_rts, usart->pin_rts, foo, 0);
 119                         usart->rts = 1;
 120                 }
 121 #endif
 122                 c = u;
 123         }
 124         return c;
 125 }
 126
 127 static char
 128 ao_usart_getchar(struct ao_stm_usart *usart)
 129 {
 130         int c;
 131         ao_arch_block_interrupts();
 132         while ((c = _ao_usart_pollchar(usart)) == AO_READ_AGAIN)
 133                 ao_sleep(&usart->rx_fifo);
 134         ao_arch_release_interrupts();
 135         return (char) c;
 136 }
 137
 138 static inline uint8_t
 139 _ao_usart_sleep_for(struct ao_stm_usart *usart, uint16_t timeout)
 140 {
 141         return ao_sleep_for(&usart->rx_fifo, timeout);
 142 }
 143
 144 static void
 145 ao_usart_putchar(struct ao_stm_usart *usart, char c)
 146 {
 147         ao_arch_block_interrupts();
 148         while (ao_fifo_full(usart->tx_fifo))
 149                 ao_sleep(&usart->tx_fifo);
 150         ao_fifo_insert(usart->tx_fifo, c);
 151         _ao_usart_tx_start(usart);
 152         ao_arch_release_interrupts();
 153 }
 154
 155 static void
 156 ao_usart_drain(struct ao_stm_usart *usart)
 157 {
 158         ao_arch_block_interrupts();
 159         while (!ao_fifo_empty(usart->tx_fifo) || usart->tx_running) {
 160                 usart->draining = 1;
 161                 ao_sleep(&usart->tx_fifo);
 162         }
 163         ao_arch_release_interrupts();
 164 }
 165
 166 static const uint32_t ao_usart_speeds[] = {
 167         [AO_SERIAL_SPEED_4800] = 4800,
 168         [AO_SERIAL_SPEED_9600] = 9600,
 169         [AO_SERIAL_SPEED_19200] = 19200,
 170         [AO_SERIAL_SPEED_57600] = 57600,
 171         [AO_SERIAL_SPEED_115200] = 115200,
 172 };
 173
 174 static void
 175 ao_usart_set_speed(struct ao_stm_usart *usart, uint8_t speed)
 176 {
 177         if (speed > AO_SERIAL_SPEED_115200)
 178                 return;
 179         usart->reg->brr = AO_PCLK / ao_usart_speeds[speed];
 180 }
 181
 182 static void
 183 ao_usart_init(struct ao_stm_usart *usart, int hw_flow)
 184 {
 185         usart->reg->cr1 = ((0 << STM_USART_CR1_M1) |
 186                            (0 << STM_USART_CR1_EOBIE) |
 187                            (0 << STM_USART_CR1_RTOIE) |
 188                            (0 << STM_USART_CR1_DEAT) |
 189                            (0 << STM_USART_CR1_DEDT) |
 190                            (0 << STM_USART_CR1_OVER8) |
 191                            (0 << STM_USART_CR1_CMIE) |
 192                            (0 << STM_USART_CR1_MME) |
 193                            (0 << STM_USART_CR1_M0) |
 194                            (0 << STM_USART_CR1_WAKE) |
 195                            (0 << STM_USART_CR1_PCE) |
 196                            (0 << STM_USART_CR1_PS) |
 197                            (0 << STM_USART_CR1_PEIE) |
 198                            (0 << STM_USART_CR1_TXEIE) |
 199                            (0 << STM_USART_CR1_TCIE) |
 200                            (1 << STM_USART_CR1_RXNEIE) |
 201                            (0 << STM_USART_CR1_IDLEIE) |
 202                            (1 << STM_USART_CR1_TE) |
 203                            (1 << STM_USART_CR1_RE) |
 204                            (0 << STM_USART_CR1_UESM) |
 205                            (0 << STM_USART_CR1_UE));
 206
 207         usart->reg->cr2 = ((0 << STM_USART_CR2_ADD) |
 208                            (0 << STM_USART_CR2_RTOEN) |
 209                            (0 << STM_USART_CR2_ABRMOD) |
 210                            (0 << STM_USART_CR2_ABREN) |
 211                            (0 << STM_USART_CR2_MSBFIRST) |
 212                            (0 << STM_USART_CR2_DATAINV) |
 213                            (0 << STM_USART_CR2_TXINV) |
 214                            (0 << STM_USART_CR2_RXINV) |
 215                            (0 << STM_USART_CR2_SWAP) |
 216                            (0 << STM_USART_CR2_LINEN) |
 217                            (0 << STM_USART_CR2_STOP) |
 218                            (0 << STM_USART_CR2_CLKEN) |
 219                            (0 << STM_USART_CR2_CPOL) |
 220                            (0 << STM_USART_CR2_CHPA) |
 221                            (0 << STM_USART_CR2_LBCL) |
 222                            (0 << STM_USART_CR2_LBDIE) |
 223                            (0 << STM_USART_CR2_LBDL) |
 224                            (0 << STM_USART_CR2_ADDM7));
 225
 226         uint32_t cr3 = ((0 << STM_USART_CR3_WUFIE) |
 227                         (0 << STM_USART_CR3_WUS) |
 228                         (0 << STM_USART_CR3_SCARCNT) |
 229                         (0 << STM_USART_CR3_DEP) |
 230                         (0 << STM_USART_CR3_DEM) |
 231                         (0 << STM_USART_CR3_DDRE) |
 232                         (0 << STM_USART_CR3_OVRDIS) |
 233                         (0 << STM_USART_CR3_ONEBIT) |
 234                         (0 << STM_USART_CR3_CTIIE) |
 235                         (0 << STM_USART_CR3_CTSE) |
 236                         (0 << STM_USART_CR3_RTSE) |
 237                         (0 << STM_USART_CR3_DMAT) |
 238                         (0 << STM_USART_CR3_DMAR) |
 239                         (0 << STM_USART_CR3_SCEN) |
 240                         (0 << STM_USART_CR3_NACK) |
 241                         (0 << STM_USART_CR3_HDSEL) |
 242                         (0 << STM_USART_CR3_IRLP) |
 243                         (0 << STM_USART_CR3_IREN) |
 244                         (0 << STM_USART_CR3_EIE));
 245
 246         if (hw_flow)
 247                 cr3 |= ((1 << STM_USART_CR3_CTSE) |
 248                         (1 << STM_USART_CR3_RTSE));
 249
 250         usart->reg->cr3 = cr3;
 251
 252         /* Pick a 9600 baud rate */
 253         ao_usart_set_speed(usart, AO_SERIAL_SPEED_9600);
 254
 255         /* Enable the usart */
 256         usart->reg->cr1 |= (1 << STM_USART_CR1_UE);
 257 }
 258
 259 #if HAS_SERIAL_1
 260
 261 struct ao_stm_usart ao_stm_usart1;
 262
 263 void stm_usart1_isr(void) { ao_usart_isr(&ao_stm_usart1, USE_SERIAL_1_STDIN); }
 264
 265 char
 266 ao_serial1_getchar(void)
 267 {
 268         return ao_usart_getchar(&ao_stm_usart1);
 269 }
 270
 271 void
 272 ao_serial1_putchar(char c)
 273 {
 274         ao_usart_putchar(&ao_stm_usart1, c);
 275 }
 276
 277 int
 278 _ao_serial1_pollchar(void)
 279 {
 280         return _ao_usart_pollchar(&ao_stm_usart1);
 281 }
 282
 283 uint8_t
 284 _ao_serial1_sleep_for(uint16_t timeout)
 285 {
 286         return _ao_usart_sleep_for(&ao_stm_usart1, timeout);
 287 }
 288
 289 void
 290 ao_serial1_drain(void)
 291 {
 292         ao_usart_drain(&ao_stm_usart1);
 293 }
 294
 295 void
 296 ao_serial1_set_speed(uint8_t speed)
 297 {
 298         ao_usart_drain(&ao_stm_usart1);
 299         ao_usart_set_speed(&ao_stm_usart1, speed);
 300 }
 301 #endif  /* HAS_SERIAL_1 */
 302
 303 #if HAS_SERIAL_2
 304
 305 struct ao_stm_usart ao_stm_usart2;
 306
 307 void stm_usart2_isr(void) { ao_usart_isr(&ao_stm_usart2, USE_SERIAL_2_STDIN); }
 308
 309 char
 310 ao_serial2_getchar(void)
 311 {
 312         return ao_usart_getchar(&ao_stm_usart2);
 313 }
 314
 315 void
 316 ao_serial2_putchar(char c)
 317 {
 318         ao_usart_putchar(&ao_stm_usart2, c);
 319 }
 320
 321 int
 322 _ao_serial2_pollchar(void)
 323 {
 324         return _ao_usart_pollchar(&ao_stm_usart2);
 325 }
 326
 327 uint8_t
 328 _ao_serial2_sleep_for(uint16_t timeout)
 329 {
 330         return _ao_usart_sleep_for(&ao_stm_usart2, timeout);
 331 }
 332
 333 void
 334 ao_serial2_drain(void)
 335 {
 336         ao_usart_drain(&ao_stm_usart2);
 337 }
 338
 339 void
 340 ao_serial2_set_speed(uint8_t speed)
 341 {
 342         ao_usart_drain(&ao_stm_usart2);
 343         ao_usart_set_speed(&ao_stm_usart2, speed);
 344 }
 345
 346 #if USE_SERIAL_2_FLOW && USE_SERIAL_2_SW_FLOW
 347 void
 348 ao_serial2_cts(void)
 349 {
 350         _ao_usart_cts(&ao_stm_usart2);
 351 }
 352 #endif
 353
 354 #endif  /* HAS_SERIAL_2 */
 355
 356 #if HAS_SERIAL_SW_FLOW
 357 static void
 358 ao_serial_set_sw_rts_cts(struct ao_stm_usart *usart,
 359                          void (*isr)(void),
 360                          struct stm_gpio *port_rts,
 361                          int pin_rts,
 362                          struct stm_gpio *port_cts,
 363                          int pin_cts)
 364 {
 365         /* Pull RTS low to note that there's space in the FIFO
 366          */
 367         ao_enable_output(port_rts, pin_rts, foo, 0);
 368         usart->gpio_rts = port_rts;
 369         usart->pin_rts = pin_rts;
 370         usart->rts = 1;
 371
 372         ao_exti_setup(port_cts, pin_cts, AO_EXTI_MODE_FALLING|AO_EXTI_PRIORITY_MED, isr);
 373         usart->gpio_cts = port_cts;
 374         usart->pin_cts = pin_cts;
 375 }
 376 #endif
 377
 378 void
 379 ao_serial_init(void)
 380 {
 381 #if HAS_SERIAL_1
 382         /*
 383          *      TX      RX
 384          *      PA9     PA10
 385          *      PB6     PB7
 386          */
 387
 388 #if SERIAL_1_PA9_PA10
 389         ao_enable_port(&stm_gpioa);
 390
 391         stm_afr_set(&stm_gpioa, 9, STM_AFR_AF1);
 392         stm_afr_set(&stm_gpioa, 10, STM_AFR_AF1);
 393 #else
 394 #if SERIAL_1_PB6_PB7
 395         ao_enable_port(&stm_gpiob);
 396
 397         stm_afr_set(&stm_gpiob, 6, STM_AFR_AF0);
 398         stm_afr_set(&stm_gpiob, 7, STM_AFR_AF0);
 399 #else
 400 #error "No SERIAL_1 port configuration specified"
 401 #endif
 402 #endif
 403         /* Enable USART */
 404         stm_rcc.apb2enr |= (1 << STM_RCC_APB2ENR_USART1EN);
 405
 406         ao_stm_usart1.reg = &stm_usart1;
 407         ao_usart_init(&ao_stm_usart1, 0);
 408
 409         stm_nvic_set_enable(STM_ISR_USART1_POS);
 410         stm_nvic_set_priority(STM_ISR_USART1_POS, 4);
 411 #if USE_SERIAL_1_STDIN && !DELAY_SERIAL_1_STDIN
 412         ao_add_stdio(_ao_serial1_pollchar,
 413                      ao_serial1_putchar,
 414                      NULL);
 415 #endif
 416 #endif
 417
 418 #if HAS_SERIAL_2
 419         /*
 420          *      TX      RX
 421          *      PA2     PA3
 422          *      PA14    PA15
 423          */
 424
 425 # if SERIAL_2_PA2_PA3
 426         ao_enable_port(&stm_gpioa);
 427         stm_afr_set(&stm_gpioa, 2, STM_AFR_AF1);
 428         stm_afr_set(&stm_gpioa, 3, STM_AFR_AF1);
 429 #  if USE_SERIAL_2_FLOW
 430 #   if USE_SERIAL_2_SW_FLOW
 431         ao_serial_set_sw_rts_cts(&ao_stm_usart2,
 432                                  ao_serial2_cts,
 433                                  SERIAL_2_PORT_RTS,
 434                                  SERIAL_2_PIN_RTS,
 435                                  SERIAL_2_PORT_CTS,
 436                                  SERIAL_2_PIN_CTS);
 437 #   else
 438         stm_afr_set(&stm_gpioa, 0, STM_AFR_AF1);
 439         stm_afr_set(&stm_gpioa, 1, STM_AFR_AF1);
 440 #   endif
 441 #  endif
 442 # else
 443 #  if SERIAL_2_PA14_PA15
 444         ao_enable_port(&stm_gpioa);
 445         stm_afr_set(&stm_gpioa, 14, STM_AFR_AF1);
 446         stm_afr_set(&stm_gpioa, 15, STM_AFR_AF1);
 447 #   if USE_SERIAL_2_FLOW
 448 #    error "Don't know how to set flowcontrol for serial 2 on PA14"
 449 #   endif
 450 #  else
 451 #   if SERIAL_2_PA2_PA15
 452         stm_rcc.ahbenr |= (1 << STM_RCC_AHBENR_IOPAEN);
 453
 454         stm_afr_set(&stm_gpioa, 2, STM_AFR_AF1);
 455         stm_afr_set(&stm_gpioa, 15, STM_AFR_AF1);
 456 #    if USE_SERIAL_2_FLOW
 457 #     error "Don't know how to set flowcontrol for serial 2 on PA2_PA15"
 458 #    endif
 459 #   else
 460 #    error "No SERIAL_2 port configuration specified"
 461 #   endif
 462 #  endif
 463 # endif
 464         /* Enable USART */
 465         stm_rcc.apb1enr |= (1 << STM_RCC_APB1ENR_USART2EN);
 466
 467         ao_stm_usart2.reg = &stm_usart2;
 468         ao_usart_init(&ao_stm_usart2, USE_SERIAL_2_FLOW && !USE_SERIAL_2_SW_FLOW);
 469
 470         stm_nvic_set_enable(STM_ISR_USART2_POS);
 471         stm_nvic_set_priority(STM_ISR_USART2_POS, 4);
 472 # if USE_SERIAL_2_STDIN && !DELAY_SERIAL_2_STDIN
 473         ao_add_stdio(_ao_serial2_pollchar,
 474                      ao_serial2_putchar,
 475                      NULL);
 476 # endif
 477 #endif
 478 }