1 /* 2 * Based on meson_uart.c, by AMLOGIC, INC. 3 * 4 * Copyright (C) 2014 Carlo Caione <carlo@caione.org> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 as published 8 * by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 */ 16 17 #include <linux/clk.h> 18 #include <linux/console.h> 19 #include <linux/delay.h> 20 #include <linux/init.h> 21 #include <linux/io.h> 22 #include <linux/module.h> 23 #include <linux/kernel.h> 24 #include <linux/of.h> 25 #include <linux/platform_device.h> 26 #include <linux/serial.h> 27 #include <linux/serial_core.h> 28 #include <linux/tty.h> 29 #include <linux/tty_flip.h> 30 31 /* Register offsets */ 32 #define AML_UART_WFIFO 0x00 33 #define AML_UART_RFIFO 0x04 34 #define AML_UART_CONTROL 0x08 35 #define AML_UART_STATUS 0x0c 36 #define AML_UART_MISC 0x10 37 #define AML_UART_REG5 0x14 38 39 /* AML_UART_CONTROL bits */ 40 #define AML_UART_TX_EN BIT(12) 41 #define AML_UART_RX_EN BIT(13) 42 #define AML_UART_TX_RST BIT(22) 43 #define AML_UART_RX_RST BIT(23) 44 #define AML_UART_CLR_ERR BIT(24) 45 #define AML_UART_RX_INT_EN BIT(27) 46 #define AML_UART_TX_INT_EN BIT(28) 47 #define AML_UART_DATA_LEN_MASK (0x03 << 20) 48 #define AML_UART_DATA_LEN_8BIT (0x00 << 20) 49 #define AML_UART_DATA_LEN_7BIT (0x01 << 20) 50 #define AML_UART_DATA_LEN_6BIT (0x02 << 20) 51 #define AML_UART_DATA_LEN_5BIT (0x03 << 20) 52 53 /* AML_UART_STATUS bits */ 54 #define AML_UART_PARITY_ERR BIT(16) 55 #define AML_UART_FRAME_ERR BIT(17) 56 #define AML_UART_TX_FIFO_WERR BIT(18) 57 #define AML_UART_RX_EMPTY BIT(20) 58 #define AML_UART_TX_FULL BIT(21) 59 #define AML_UART_TX_EMPTY BIT(22) 60 #define AML_UART_XMIT_BUSY BIT(25) 61 #define AML_UART_ERR (AML_UART_PARITY_ERR | \ 62 AML_UART_FRAME_ERR | \ 63 AML_UART_TX_FIFO_WERR) 64 65 /* AML_UART_CONTROL bits */ 66 #define AML_UART_TWO_WIRE_EN BIT(15) 67 #define AML_UART_PARITY_TYPE BIT(18) 68 #define AML_UART_PARITY_EN BIT(19) 69 #define AML_UART_CLEAR_ERR BIT(24) 70 #define AML_UART_STOP_BIN_LEN_MASK (0x03 << 16) 71 #define AML_UART_STOP_BIN_1SB (0x00 << 16) 72 #define AML_UART_STOP_BIN_2SB (0x01 << 16) 73 74 /* AML_UART_MISC bits */ 75 #define AML_UART_XMIT_IRQ(c) (((c) & 0xff) << 8) 76 #define AML_UART_RECV_IRQ(c) ((c) & 0xff) 77 78 /* AML_UART_REG5 bits */ 79 #define AML_UART_BAUD_MASK 0x7fffff 80 #define AML_UART_BAUD_USE BIT(23) 81 #define AML_UART_BAUD_XTAL BIT(24) 82 83 #define AML_UART_PORT_NUM 6 84 #define AML_UART_DEV_NAME "ttyAML" 85 86 87 static struct uart_driver meson_uart_driver; 88 89 static struct uart_port *meson_ports[AML_UART_PORT_NUM]; 90 91 static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) 92 { 93 } 94 95 static unsigned int meson_uart_get_mctrl(struct uart_port *port) 96 { 97 return TIOCM_CTS; 98 } 99 100 static unsigned int meson_uart_tx_empty(struct uart_port *port) 101 { 102 u32 val; 103 104 val = readl(port->membase + AML_UART_STATUS); 105 val &= (AML_UART_TX_EMPTY | AML_UART_XMIT_BUSY); 106 return (val == AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0; 107 } 108 109 static void meson_uart_stop_tx(struct uart_port *port) 110 { 111 u32 val; 112 113 val = readl(port->membase + AML_UART_CONTROL); 114 val &= ~AML_UART_TX_INT_EN; 115 writel(val, port->membase + AML_UART_CONTROL); 116 } 117 118 static void meson_uart_stop_rx(struct uart_port *port) 119 { 120 u32 val; 121 122 val = readl(port->membase + AML_UART_CONTROL); 123 val &= ~AML_UART_RX_EN; 124 writel(val, port->membase + AML_UART_CONTROL); 125 } 126 127 static void meson_uart_shutdown(struct uart_port *port) 128 { 129 unsigned long flags; 130 u32 val; 131 132 free_irq(port->irq, port); 133 134 spin_lock_irqsave(&port->lock, flags); 135 136 val = readl(port->membase + AML_UART_CONTROL); 137 val &= ~AML_UART_RX_EN; 138 val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN); 139 writel(val, port->membase + AML_UART_CONTROL); 140 141 spin_unlock_irqrestore(&port->lock, flags); 142 } 143 144 static void meson_uart_start_tx(struct uart_port *port) 145 { 146 struct circ_buf *xmit = &port->state->xmit; 147 unsigned int ch; 148 u32 val; 149 150 if (uart_tx_stopped(port)) { 151 meson_uart_stop_tx(port); 152 return; 153 } 154 155 while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) { 156 if (port->x_char) { 157 writel(port->x_char, port->membase + AML_UART_WFIFO); 158 port->icount.tx++; 159 port->x_char = 0; 160 continue; 161 } 162 163 if (uart_circ_empty(xmit)) 164 break; 165 166 ch = xmit->buf[xmit->tail]; 167 writel(ch, port->membase + AML_UART_WFIFO); 168 xmit->tail = (xmit->tail+1) & (SERIAL_XMIT_SIZE - 1); 169 port->icount.tx++; 170 } 171 172 if (!uart_circ_empty(xmit)) { 173 val = readl(port->membase + AML_UART_CONTROL); 174 val |= AML_UART_TX_INT_EN; 175 writel(val, port->membase + AML_UART_CONTROL); 176 } 177 178 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 179 uart_write_wakeup(port); 180 } 181 182 static void meson_receive_chars(struct uart_port *port) 183 { 184 struct tty_port *tport = &port->state->port; 185 char flag; 186 u32 status, ch, mode; 187 188 do { 189 flag = TTY_NORMAL; 190 port->icount.rx++; 191 status = readl(port->membase + AML_UART_STATUS); 192 193 if (status & AML_UART_ERR) { 194 if (status & AML_UART_TX_FIFO_WERR) 195 port->icount.overrun++; 196 else if (status & AML_UART_FRAME_ERR) 197 port->icount.frame++; 198 else if (status & AML_UART_PARITY_ERR) 199 port->icount.frame++; 200 201 mode = readl(port->membase + AML_UART_CONTROL); 202 mode |= AML_UART_CLEAR_ERR; 203 writel(mode, port->membase + AML_UART_CONTROL); 204 205 /* It doesn't clear to 0 automatically */ 206 mode &= ~AML_UART_CLEAR_ERR; 207 writel(mode, port->membase + AML_UART_CONTROL); 208 209 status &= port->read_status_mask; 210 if (status & AML_UART_FRAME_ERR) 211 flag = TTY_FRAME; 212 else if (status & AML_UART_PARITY_ERR) 213 flag = TTY_PARITY; 214 } 215 216 ch = readl(port->membase + AML_UART_RFIFO); 217 ch &= 0xff; 218 219 if ((status & port->ignore_status_mask) == 0) 220 tty_insert_flip_char(tport, ch, flag); 221 222 if (status & AML_UART_TX_FIFO_WERR) 223 tty_insert_flip_char(tport, 0, TTY_OVERRUN); 224 225 } while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)); 226 227 spin_unlock(&port->lock); 228 tty_flip_buffer_push(tport); 229 spin_lock(&port->lock); 230 } 231 232 static irqreturn_t meson_uart_interrupt(int irq, void *dev_id) 233 { 234 struct uart_port *port = (struct uart_port *)dev_id; 235 236 spin_lock(&port->lock); 237 238 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)) 239 meson_receive_chars(port); 240 241 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) { 242 if (readl(port->membase + AML_UART_CONTROL) & AML_UART_TX_INT_EN) 243 meson_uart_start_tx(port); 244 } 245 246 spin_unlock(&port->lock); 247 248 return IRQ_HANDLED; 249 } 250 251 static const char *meson_uart_type(struct uart_port *port) 252 { 253 return (port->type == PORT_MESON) ? "meson_uart" : NULL; 254 } 255 256 static void meson_uart_reset(struct uart_port *port) 257 { 258 u32 val; 259 260 val = readl(port->membase + AML_UART_CONTROL); 261 val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR); 262 writel(val, port->membase + AML_UART_CONTROL); 263 264 val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR); 265 writel(val, port->membase + AML_UART_CONTROL); 266 } 267 268 static int meson_uart_startup(struct uart_port *port) 269 { 270 u32 val; 271 int ret = 0; 272 273 val = readl(port->membase + AML_UART_CONTROL); 274 val |= AML_UART_CLR_ERR; 275 writel(val, port->membase + AML_UART_CONTROL); 276 val &= ~AML_UART_CLR_ERR; 277 writel(val, port->membase + AML_UART_CONTROL); 278 279 val |= (AML_UART_RX_EN | AML_UART_TX_EN); 280 writel(val, port->membase + AML_UART_CONTROL); 281 282 val |= (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN); 283 writel(val, port->membase + AML_UART_CONTROL); 284 285 val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2)); 286 writel(val, port->membase + AML_UART_MISC); 287 288 ret = request_irq(port->irq, meson_uart_interrupt, 0, 289 meson_uart_type(port), port); 290 291 return ret; 292 } 293 294 static void meson_uart_change_speed(struct uart_port *port, unsigned long baud) 295 { 296 u32 val; 297 298 while (!meson_uart_tx_empty(port)) 299 cpu_relax(); 300 301 val = readl(port->membase + AML_UART_REG5); 302 val &= ~AML_UART_BAUD_MASK; 303 if (port->uartclk == 24000000) { 304 val = ((port->uartclk / 3) / baud) - 1; 305 val |= AML_UART_BAUD_XTAL; 306 } else { 307 val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1; 308 } 309 val |= AML_UART_BAUD_USE; 310 writel(val, port->membase + AML_UART_REG5); 311 } 312 313 static void meson_uart_set_termios(struct uart_port *port, 314 struct ktermios *termios, 315 struct ktermios *old) 316 { 317 unsigned int cflags, iflags, baud; 318 unsigned long flags; 319 u32 val; 320 321 spin_lock_irqsave(&port->lock, flags); 322 323 cflags = termios->c_cflag; 324 iflags = termios->c_iflag; 325 326 val = readl(port->membase + AML_UART_CONTROL); 327 328 val &= ~AML_UART_DATA_LEN_MASK; 329 switch (cflags & CSIZE) { 330 case CS8: 331 val |= AML_UART_DATA_LEN_8BIT; 332 break; 333 case CS7: 334 val |= AML_UART_DATA_LEN_7BIT; 335 break; 336 case CS6: 337 val |= AML_UART_DATA_LEN_6BIT; 338 break; 339 case CS5: 340 val |= AML_UART_DATA_LEN_5BIT; 341 break; 342 } 343 344 if (cflags & PARENB) 345 val |= AML_UART_PARITY_EN; 346 else 347 val &= ~AML_UART_PARITY_EN; 348 349 if (cflags & PARODD) 350 val |= AML_UART_PARITY_TYPE; 351 else 352 val &= ~AML_UART_PARITY_TYPE; 353 354 val &= ~AML_UART_STOP_BIN_LEN_MASK; 355 if (cflags & CSTOPB) 356 val |= AML_UART_STOP_BIN_2SB; 357 else 358 val &= ~AML_UART_STOP_BIN_1SB; 359 360 if (cflags & CRTSCTS) 361 val &= ~AML_UART_TWO_WIRE_EN; 362 else 363 val |= AML_UART_TWO_WIRE_EN; 364 365 writel(val, port->membase + AML_UART_CONTROL); 366 367 baud = uart_get_baud_rate(port, termios, old, 9600, 115200); 368 meson_uart_change_speed(port, baud); 369 370 port->read_status_mask = AML_UART_TX_FIFO_WERR; 371 if (iflags & INPCK) 372 port->read_status_mask |= AML_UART_PARITY_ERR | 373 AML_UART_FRAME_ERR; 374 375 port->ignore_status_mask = 0; 376 if (iflags & IGNPAR) 377 port->ignore_status_mask |= AML_UART_PARITY_ERR | 378 AML_UART_FRAME_ERR; 379 380 uart_update_timeout(port, termios->c_cflag, baud); 381 spin_unlock_irqrestore(&port->lock, flags); 382 } 383 384 static int meson_uart_verify_port(struct uart_port *port, 385 struct serial_struct *ser) 386 { 387 int ret = 0; 388 389 if (port->type != PORT_MESON) 390 ret = -EINVAL; 391 if (port->irq != ser->irq) 392 ret = -EINVAL; 393 if (ser->baud_base < 9600) 394 ret = -EINVAL; 395 return ret; 396 } 397 398 static int meson_uart_res_size(struct uart_port *port) 399 { 400 struct platform_device *pdev = to_platform_device(port->dev); 401 struct resource *res; 402 403 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 404 if (!res) { 405 dev_err(port->dev, "cannot obtain I/O memory region"); 406 return -ENODEV; 407 } 408 409 return resource_size(res); 410 } 411 412 static void meson_uart_release_port(struct uart_port *port) 413 { 414 int size = meson_uart_res_size(port); 415 416 if (port->flags & UPF_IOREMAP) { 417 devm_release_mem_region(port->dev, port->mapbase, size); 418 devm_iounmap(port->dev, port->membase); 419 port->membase = NULL; 420 } 421 } 422 423 static int meson_uart_request_port(struct uart_port *port) 424 { 425 int size = meson_uart_res_size(port); 426 427 if (size < 0) 428 return size; 429 430 if (!devm_request_mem_region(port->dev, port->mapbase, size, 431 dev_name(port->dev))) { 432 dev_err(port->dev, "Memory region busy\n"); 433 return -EBUSY; 434 } 435 436 if (port->flags & UPF_IOREMAP) { 437 port->membase = devm_ioremap_nocache(port->dev, 438 port->mapbase, 439 size); 440 if (port->membase == NULL) 441 return -ENOMEM; 442 } 443 444 return 0; 445 } 446 447 static void meson_uart_config_port(struct uart_port *port, int flags) 448 { 449 if (flags & UART_CONFIG_TYPE) { 450 port->type = PORT_MESON; 451 meson_uart_request_port(port); 452 } 453 } 454 455 static struct uart_ops meson_uart_ops = { 456 .set_mctrl = meson_uart_set_mctrl, 457 .get_mctrl = meson_uart_get_mctrl, 458 .tx_empty = meson_uart_tx_empty, 459 .start_tx = meson_uart_start_tx, 460 .stop_tx = meson_uart_stop_tx, 461 .stop_rx = meson_uart_stop_rx, 462 .startup = meson_uart_startup, 463 .shutdown = meson_uart_shutdown, 464 .set_termios = meson_uart_set_termios, 465 .type = meson_uart_type, 466 .config_port = meson_uart_config_port, 467 .request_port = meson_uart_request_port, 468 .release_port = meson_uart_release_port, 469 .verify_port = meson_uart_verify_port, 470 }; 471 472 #ifdef CONFIG_SERIAL_MESON_CONSOLE 473 474 static void meson_console_putchar(struct uart_port *port, int ch) 475 { 476 if (!port->membase) 477 return; 478 479 while (readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL) 480 cpu_relax(); 481 writel(ch, port->membase + AML_UART_WFIFO); 482 } 483 484 static void meson_serial_console_write(struct console *co, const char *s, 485 u_int count) 486 { 487 struct uart_port *port; 488 unsigned long flags; 489 int locked; 490 u32 val, tmp; 491 492 port = meson_ports[co->index]; 493 if (!port) 494 return; 495 496 local_irq_save(flags); 497 if (port->sysrq) { 498 locked = 0; 499 } else if (oops_in_progress) { 500 locked = spin_trylock(&port->lock); 501 } else { 502 spin_lock(&port->lock); 503 locked = 1; 504 } 505 506 val = readl(port->membase + AML_UART_CONTROL); 507 val |= AML_UART_TX_EN; 508 tmp = val & ~(AML_UART_TX_INT_EN | AML_UART_RX_INT_EN); 509 writel(tmp, port->membase + AML_UART_CONTROL); 510 511 uart_console_write(port, s, count, meson_console_putchar); 512 writel(val, port->membase + AML_UART_CONTROL); 513 514 if (locked) 515 spin_unlock(&port->lock); 516 local_irq_restore(flags); 517 } 518 519 static int meson_serial_console_setup(struct console *co, char *options) 520 { 521 struct uart_port *port; 522 int baud = 115200; 523 int bits = 8; 524 int parity = 'n'; 525 int flow = 'n'; 526 527 if (co->index < 0 || co->index >= AML_UART_PORT_NUM) 528 return -EINVAL; 529 530 port = meson_ports[co->index]; 531 if (!port || !port->membase) 532 return -ENODEV; 533 534 if (options) 535 uart_parse_options(options, &baud, &parity, &bits, &flow); 536 537 return uart_set_options(port, co, baud, parity, bits, flow); 538 } 539 540 static struct console meson_serial_console = { 541 .name = AML_UART_DEV_NAME, 542 .write = meson_serial_console_write, 543 .device = uart_console_device, 544 .setup = meson_serial_console_setup, 545 .flags = CON_PRINTBUFFER, 546 .index = -1, 547 .data = &meson_uart_driver, 548 }; 549 550 static int __init meson_serial_console_init(void) 551 { 552 register_console(&meson_serial_console); 553 return 0; 554 } 555 console_initcall(meson_serial_console_init); 556 557 #define MESON_SERIAL_CONSOLE (&meson_serial_console) 558 #else 559 #define MESON_SERIAL_CONSOLE NULL 560 #endif 561 562 static struct uart_driver meson_uart_driver = { 563 .owner = THIS_MODULE, 564 .driver_name = "meson_uart", 565 .dev_name = AML_UART_DEV_NAME, 566 .nr = AML_UART_PORT_NUM, 567 .cons = MESON_SERIAL_CONSOLE, 568 }; 569 570 static int meson_uart_probe(struct platform_device *pdev) 571 { 572 struct resource *res_mem, *res_irq; 573 struct uart_port *port; 574 struct clk *clk; 575 int ret = 0; 576 577 if (pdev->dev.of_node) 578 pdev->id = of_alias_get_id(pdev->dev.of_node, "serial"); 579 580 if (pdev->id < 0 || pdev->id >= AML_UART_PORT_NUM) 581 return -EINVAL; 582 583 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 584 if (!res_mem) 585 return -ENODEV; 586 587 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 588 if (!res_irq) 589 return -ENODEV; 590 591 if (meson_ports[pdev->id]) { 592 dev_err(&pdev->dev, "port %d already allocated\n", pdev->id); 593 return -EBUSY; 594 } 595 596 port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL); 597 if (!port) 598 return -ENOMEM; 599 600 clk = clk_get(&pdev->dev, NULL); 601 if (IS_ERR(clk)) 602 return PTR_ERR(clk); 603 604 port->uartclk = clk_get_rate(clk); 605 port->iotype = UPIO_MEM; 606 port->mapbase = res_mem->start; 607 port->irq = res_irq->start; 608 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY; 609 port->dev = &pdev->dev; 610 port->line = pdev->id; 611 port->type = PORT_MESON; 612 port->x_char = 0; 613 port->ops = &meson_uart_ops; 614 port->fifosize = 64; 615 616 meson_ports[pdev->id] = port; 617 platform_set_drvdata(pdev, port); 618 619 /* reset port before registering (and possibly registering console) */ 620 if (meson_uart_request_port(port) >= 0) { 621 meson_uart_reset(port); 622 meson_uart_release_port(port); 623 } 624 625 ret = uart_add_one_port(&meson_uart_driver, port); 626 if (ret) 627 meson_ports[pdev->id] = NULL; 628 629 return ret; 630 } 631 632 static int meson_uart_remove(struct platform_device *pdev) 633 { 634 struct uart_port *port; 635 636 port = platform_get_drvdata(pdev); 637 uart_remove_one_port(&meson_uart_driver, port); 638 meson_ports[pdev->id] = NULL; 639 640 return 0; 641 } 642 643 644 static const struct of_device_id meson_uart_dt_match[] = { 645 { .compatible = "amlogic,meson-uart" }, 646 { /* sentinel */ }, 647 }; 648 MODULE_DEVICE_TABLE(of, meson_uart_dt_match); 649 650 static struct platform_driver meson_uart_platform_driver = { 651 .probe = meson_uart_probe, 652 .remove = meson_uart_remove, 653 .driver = { 654 .name = "meson_uart", 655 .of_match_table = meson_uart_dt_match, 656 }, 657 }; 658 659 static int __init meson_uart_init(void) 660 { 661 int ret; 662 663 ret = uart_register_driver(&meson_uart_driver); 664 if (ret) 665 return ret; 666 667 ret = platform_driver_register(&meson_uart_platform_driver); 668 if (ret) 669 uart_unregister_driver(&meson_uart_driver); 670 671 return ret; 672 } 673 674 static void __exit meson_uart_exit(void) 675 { 676 platform_driver_unregister(&meson_uart_platform_driver); 677 uart_unregister_driver(&meson_uart_driver); 678 } 679 680 module_init(meson_uart_init); 681 module_exit(meson_uart_exit); 682 683 MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); 684 MODULE_DESCRIPTION("Amlogic Meson serial port driver"); 685 MODULE_LICENSE("GPL v2"); 686