1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2019 Axiado Corporation 5 * All rights reserved. 6 * 7 * This software was developed in part by Kristof Provost under contract for 8 * Axiado Corporation. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/bus.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/module.h> 41 #include <sys/mutex.h> 42 #include <sys/rman.h> 43 44 #include <machine/bus.h> 45 #include <machine/cpu.h> 46 47 #include <dev/extres/clk/clk.h> 48 49 #include <dev/ofw/ofw_bus.h> 50 #include <dev/ofw/ofw_bus_subr.h> 51 #include <dev/ofw/openfirm.h> 52 53 #include <dev/uart/uart.h> 54 #include <dev/uart/uart_bus.h> 55 #include <dev/uart/uart_cpu.h> 56 #include <dev/uart/uart_cpu_fdt.h> 57 58 #include "uart_if.h" 59 60 #define SFUART_TXDATA 0x00 61 #define SFUART_TXDATA_FULL (1 << 31) 62 #define SFUART_RXDATA 0x04 63 #define SFUART_RXDATA_EMPTY (1 << 31) 64 #define SFUART_TXCTRL 0x08 65 #define SFUART_TXCTRL_ENABLE 0x01 66 #define SFUART_TXCTRL_NSTOP 0x02 67 #define SFUART_TXCTRL_TXCNT 0x70000 68 #define SFUART_TXCTRL_TXCNT_SHIFT 16 69 #define SFUART_RXCTRL 0x0c 70 #define SFUART_RXCTRL_ENABLE 0x01 71 #define SFUART_RXCTRL_RXCNT 0x70000 72 #define SFUART_RXCTRL_RXCNT_SHIFT 16 73 #define SFUART_IRQ_ENABLE 0x10 74 #define SFUART_IRQ_ENABLE_TXWM 0x01 75 #define SFUART_IRQ_ENABLE_RXWM 0x02 76 #define SFUART_IRQ_PENDING 0x14 77 #define SFUART_IRQ_PENDING_TXWM 0x01 78 #define SFUART_IRQ_PENDING_RXQM 0x02 79 #define SFUART_DIV 0x18 80 #define SFUART_REGS_SIZE 0x1c 81 82 #define SFUART_RX_FIFO_DEPTH 8 83 #define SFUART_TX_FIFO_DEPTH 8 84 85 struct sfuart_softc { 86 struct uart_softc uart_softc; 87 clk_t clk; 88 }; 89 90 static int 91 sfuart_probe(struct uart_bas *bas) 92 { 93 94 bas->regiowidth = 4; 95 96 return (0); 97 } 98 99 static void 100 sfuart_init(struct uart_bas *bas, int baudrate, int databits, int stopbits, 101 int parity) 102 { 103 uint32_t reg; 104 105 uart_setreg(bas, SFUART_IRQ_ENABLE, 0); 106 107 /* Enable RX and configure the watermark so that we get an interrupt 108 * when a single character arrives (if interrupts are enabled). */ 109 reg = SFUART_RXCTRL_ENABLE; 110 reg |= (0 << SFUART_RXCTRL_RXCNT_SHIFT); 111 uart_setreg(bas, SFUART_RXCTRL, reg); 112 113 /* Enable TX and configure the watermark so that we get an interrupt 114 * when there's room for one more character in the TX fifo (if 115 * interrupts are enabled). */ 116 reg = SFUART_TXCTRL_ENABLE; 117 reg |= (1 << SFUART_TXCTRL_TXCNT_SHIFT); 118 if (stopbits == 2) 119 reg |= SFUART_TXCTRL_NSTOP; 120 uart_setreg(bas, SFUART_TXCTRL, reg); 121 122 /* Don't touch DIV. Assume that's set correctly until we can 123 * reconfigure. */ 124 } 125 126 static void 127 sfuart_putc(struct uart_bas *bas, int c) 128 { 129 130 while ((uart_getreg(bas, SFUART_TXDATA) & SFUART_TXDATA_FULL) 131 != 0) 132 cpu_spinwait(); 133 134 uart_setreg(bas, SFUART_TXDATA, c); 135 } 136 137 static int 138 sfuart_rxready(struct uart_bas *bas) 139 { 140 /* 141 * Unfortunately the FIFO empty flag is in the FIFO data register so 142 * reading it would dequeue the character. Instead, rely on the fact 143 * we've configured the watermark to be 0 and that interrupts are off 144 * when using the low-level console function, and read the interrupt 145 * pending state instead. 146 */ 147 return ((uart_getreg(bas, SFUART_IRQ_PENDING) & 148 SFUART_IRQ_PENDING_RXQM) != 0); 149 } 150 151 static int 152 sfuart_getc(struct uart_bas *bas, struct mtx *hwmtx) 153 { 154 int c; 155 156 uart_lock(hwmtx); 157 158 while (((c = uart_getreg(bas, SFUART_RXDATA)) & 159 SFUART_RXDATA_EMPTY) != 0) { 160 uart_unlock(hwmtx); 161 DELAY(4); 162 uart_lock(hwmtx); 163 } 164 165 uart_unlock(hwmtx); 166 167 return (c & 0xff); 168 } 169 170 static int 171 sfuart_bus_probe(struct uart_softc *sc) 172 { 173 int error; 174 175 error = sfuart_probe(&sc->sc_bas); 176 if (error) 177 return (error); 178 179 sc->sc_rxfifosz = SFUART_RX_FIFO_DEPTH; 180 sc->sc_txfifosz = SFUART_TX_FIFO_DEPTH; 181 sc->sc_hwiflow = 0; 182 sc->sc_hwoflow = 0; 183 184 device_set_desc(sc->sc_dev, "SiFive UART"); 185 186 return (0); 187 } 188 189 static int 190 sfuart_bus_attach(struct uart_softc *sc) 191 { 192 struct uart_bas *bas; 193 struct sfuart_softc *sfsc; 194 uint64_t freq; 195 uint32_t reg; 196 int error; 197 198 sfsc = (struct sfuart_softc *)sc; 199 bas = &sc->sc_bas; 200 201 error = clk_get_by_ofw_index(sc->sc_dev, 0, 0, &sfsc->clk); 202 if (error) { 203 device_printf(sc->sc_dev, "couldn't allocate clock\n"); 204 return (ENXIO); 205 } 206 207 error = clk_enable(sfsc->clk); 208 if (error) { 209 device_printf(sc->sc_dev, "couldn't enable clock\n"); 210 return (ENXIO); 211 } 212 213 error = clk_get_freq(sfsc->clk, &freq); 214 if (error || freq == 0) { 215 clk_disable(sfsc->clk); 216 device_printf(sc->sc_dev, "couldn't get clock frequency\n"); 217 return (ENXIO); 218 } 219 220 bas->rclk = freq; 221 222 /* Enable RX/RX */ 223 reg = SFUART_RXCTRL_ENABLE; 224 reg |= (0 << SFUART_RXCTRL_RXCNT_SHIFT); 225 uart_setreg(bas, SFUART_RXCTRL, reg); 226 227 reg = SFUART_TXCTRL_ENABLE; 228 reg |= (1 << SFUART_TXCTRL_TXCNT_SHIFT); 229 uart_setreg(bas, SFUART_TXCTRL, reg); 230 231 /* Enable RX interrupt */ 232 uart_setreg(bas, SFUART_IRQ_ENABLE, SFUART_IRQ_ENABLE_RXWM); 233 234 return (0); 235 } 236 237 static int 238 sfuart_bus_detach(struct uart_softc *sc) 239 { 240 struct sfuart_softc *sfsc; 241 struct uart_bas *bas; 242 243 sfsc = (struct sfuart_softc *)sc; 244 bas = &sc->sc_bas; 245 246 /* Disable RX/TX */ 247 uart_setreg(bas, SFUART_RXCTRL, 0); 248 uart_setreg(bas, SFUART_TXCTRL, 0); 249 250 /* Disable interrupts */ 251 uart_setreg(bas, SFUART_IRQ_ENABLE, 0); 252 253 clk_disable(sfsc->clk); 254 255 return (0); 256 } 257 258 static int 259 sfuart_bus_flush(struct uart_softc *sc, int what) 260 { 261 struct uart_bas *bas; 262 uint32_t reg; 263 264 bas = &sc->sc_bas; 265 uart_lock(sc->sc_hwmtx); 266 267 if (what & UART_FLUSH_TRANSMITTER) { 268 do { 269 reg = uart_getreg(bas, SFUART_TXDATA); 270 } while ((reg & SFUART_TXDATA_FULL) != 0); 271 } 272 273 if (what & UART_FLUSH_RECEIVER) { 274 do { 275 reg = uart_getreg(bas, SFUART_RXDATA); 276 } while ((reg & SFUART_RXDATA_EMPTY) == 0); 277 } 278 uart_unlock(sc->sc_hwmtx); 279 280 return (0); 281 } 282 283 #define SIGCHG(c, i, s, d) \ 284 do { \ 285 if (c) \ 286 i |= ((i) & (s)) ? (s) : (s) | (d); \ 287 else \ 288 i = ((i) & (s)) ? ((i) & ~(s)) | (d) : (i); \ 289 } while (0) 290 291 static int 292 sfuart_bus_getsig(struct uart_softc *sc) 293 { 294 uint32_t new, old, sig; 295 296 do { 297 old = sc->sc_hwsig; 298 sig = old; 299 SIGCHG(1, sig, SER_DSR, SER_DDSR); 300 SIGCHG(1, sig, SER_DCD, SER_DDCD); 301 SIGCHG(1, sig, SER_CTS, SER_DCTS); 302 new = sig & ~SER_MASK_DELTA; 303 } while (!atomic_cmpset_32(&sc->sc_hwsig, old, new)); 304 305 return (sig); 306 } 307 308 static int 309 sfuart_bus_setsig(struct uart_softc *sc, int sig) 310 { 311 uint32_t new, old; 312 313 do { 314 old = sc->sc_hwsig; 315 new = old; 316 if (sig & SER_DDTR) { 317 SIGCHG(sig & SER_DTR, new, SER_DTR, SER_DDTR); 318 } 319 if (sig & SER_DRTS) { 320 SIGCHG(sig & SER_RTS, new, SER_RTS, SER_DRTS); 321 } 322 } while (!atomic_cmpset_32(&sc->sc_hwsig, old, new)); 323 324 return (0); 325 } 326 327 static int 328 sfuart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data) 329 { 330 struct uart_bas *bas; 331 uint32_t reg; 332 int error; 333 334 bas = &sc->sc_bas; 335 336 uart_lock(sc->sc_hwmtx); 337 338 switch (request) { 339 case UART_IOCTL_BAUD: 340 reg = uart_getreg(bas, SFUART_DIV); 341 if (reg == 0) { 342 /* Possible if the divisor hasn't been set up yet. */ 343 error = ENXIO; 344 break; 345 } 346 *(int*)data = bas->rclk / (reg + 1); 347 error = 0; 348 break; 349 default: 350 error = EINVAL; 351 break; 352 } 353 354 uart_unlock(sc->sc_hwmtx); 355 356 return (error); 357 } 358 359 static int 360 sfuart_bus_ipend(struct uart_softc *sc) 361 { 362 struct uart_bas *bas; 363 int ipend; 364 uint32_t reg, ie; 365 366 bas = &sc->sc_bas; 367 uart_lock(sc->sc_hwmtx); 368 369 ipend = 0; 370 reg = uart_getreg(bas, SFUART_IRQ_PENDING); 371 ie = uart_getreg(bas, SFUART_IRQ_ENABLE); 372 373 if ((reg & SFUART_IRQ_PENDING_TXWM) != 0 && 374 (ie & SFUART_IRQ_ENABLE_TXWM) != 0) { 375 ipend |= SER_INT_TXIDLE; 376 377 /* Disable TX interrupt */ 378 ie &= ~(SFUART_IRQ_ENABLE_TXWM); 379 uart_setreg(bas, SFUART_IRQ_ENABLE, ie); 380 } 381 382 if ((reg & SFUART_IRQ_PENDING_RXQM) != 0) 383 ipend |= SER_INT_RXREADY; 384 385 uart_unlock(sc->sc_hwmtx); 386 387 return (ipend); 388 } 389 390 static int 391 sfuart_bus_param(struct uart_softc *sc, int baudrate, int databits, 392 int stopbits, int parity) 393 { 394 struct uart_bas *bas; 395 uint32_t reg; 396 397 bas = &sc->sc_bas; 398 399 if (databits != 8) 400 return (EINVAL); 401 402 if (parity != UART_PARITY_NONE) 403 return (EINVAL); 404 405 uart_lock(sc->sc_hwmtx); 406 407 reg = uart_getreg(bas, SFUART_TXCTRL); 408 if (stopbits == 2) { 409 reg |= SFUART_TXCTRL_NSTOP; 410 } else if (stopbits == 1) { 411 reg &= ~SFUART_TXCTRL_NSTOP; 412 } else { 413 uart_unlock(sc->sc_hwmtx); 414 return (EINVAL); 415 } 416 417 if (baudrate > 0 && bas->rclk != 0) { 418 reg = (bas->rclk / baudrate) - 1; 419 uart_setreg(bas, SFUART_DIV, reg); 420 } 421 422 uart_unlock(sc->sc_hwmtx); 423 return (0); 424 } 425 426 static int 427 sfuart_bus_receive(struct uart_softc *sc) 428 { 429 struct uart_bas *bas; 430 uint32_t reg; 431 432 bas = &sc->sc_bas; 433 uart_lock(sc->sc_hwmtx); 434 435 reg = uart_getreg(bas, SFUART_RXDATA); 436 while ((reg & SFUART_RXDATA_EMPTY) == 0) { 437 if (uart_rx_full(sc)) { 438 sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN; 439 break; 440 } 441 442 uart_rx_put(sc, reg & 0xff); 443 444 reg = uart_getreg(bas, SFUART_RXDATA); 445 } 446 447 uart_unlock(sc->sc_hwmtx); 448 449 return (0); 450 } 451 452 static int 453 sfuart_bus_transmit(struct uart_softc *sc) 454 { 455 struct uart_bas *bas; 456 int i; 457 uint32_t reg; 458 459 bas = &sc->sc_bas; 460 uart_lock(sc->sc_hwmtx); 461 462 reg = uart_getreg(bas, SFUART_IRQ_ENABLE); 463 reg |= SFUART_IRQ_ENABLE_TXWM; 464 uart_setreg(bas, SFUART_IRQ_ENABLE, reg); 465 466 for (i = 0; i < sc->sc_txdatasz; i++) 467 sfuart_putc(bas, sc->sc_txbuf[i]); 468 469 sc->sc_txbusy = 1; 470 471 uart_unlock(sc->sc_hwmtx); 472 473 return (0); 474 } 475 476 static void 477 sfuart_bus_grab(struct uart_softc *sc) 478 { 479 struct uart_bas *bas; 480 uint32_t reg; 481 482 bas = &sc->sc_bas; 483 uart_lock(sc->sc_hwmtx); 484 485 reg = uart_getreg(bas, SFUART_IRQ_ENABLE); 486 reg &= ~(SFUART_IRQ_ENABLE_TXWM | SFUART_IRQ_PENDING_RXQM); 487 uart_setreg(bas, SFUART_IRQ_ENABLE, reg); 488 489 uart_unlock(sc->sc_hwmtx); 490 } 491 492 static void 493 sfuart_bus_ungrab(struct uart_softc *sc) 494 { 495 struct uart_bas *bas; 496 uint32_t reg; 497 498 bas = &sc->sc_bas; 499 uart_lock(sc->sc_hwmtx); 500 501 reg = uart_getreg(bas, SFUART_IRQ_ENABLE); 502 reg |= SFUART_IRQ_ENABLE_TXWM | SFUART_IRQ_PENDING_RXQM; 503 uart_setreg(bas, SFUART_IRQ_ENABLE, reg); 504 505 uart_unlock(sc->sc_hwmtx); 506 } 507 508 static kobj_method_t sfuart_methods[] = { 509 KOBJMETHOD(uart_probe, sfuart_bus_probe), 510 KOBJMETHOD(uart_attach, sfuart_bus_attach), 511 KOBJMETHOD(uart_detach, sfuart_bus_detach), 512 KOBJMETHOD(uart_flush, sfuart_bus_flush), 513 KOBJMETHOD(uart_getsig, sfuart_bus_getsig), 514 KOBJMETHOD(uart_setsig, sfuart_bus_setsig), 515 KOBJMETHOD(uart_ioctl, sfuart_bus_ioctl), 516 KOBJMETHOD(uart_ipend, sfuart_bus_ipend), 517 KOBJMETHOD(uart_param, sfuart_bus_param), 518 KOBJMETHOD(uart_receive, sfuart_bus_receive), 519 KOBJMETHOD(uart_transmit, sfuart_bus_transmit), 520 KOBJMETHOD(uart_grab, sfuart_bus_grab), 521 KOBJMETHOD(uart_ungrab, sfuart_bus_ungrab), 522 KOBJMETHOD_END 523 }; 524 525 static struct uart_ops sfuart_ops = { 526 .probe = sfuart_probe, 527 .init = sfuart_init, 528 .term = NULL, 529 .putc = sfuart_putc, 530 .rxready = sfuart_rxready, 531 .getc = sfuart_getc, 532 }; 533 534 struct uart_class sfuart_class = { 535 "sifiveuart", 536 sfuart_methods, 537 sizeof(struct sfuart_softc), 538 .uc_ops = &sfuart_ops, 539 .uc_range = SFUART_REGS_SIZE, 540 .uc_rclk = 0, 541 .uc_rshift = 0 542 }; 543 544 static struct ofw_compat_data compat_data[] = { 545 { "sifive,uart0", (uintptr_t)&sfuart_class }, 546 { NULL, (uintptr_t)NULL } 547 }; 548 549 UART_FDT_CLASS_AND_DEVICE(compat_data); 550