1 /* 2 * altera_jtaguart.c -- Altera JTAG UART driver 3 * 4 * Based on mcf.c -- Freescale ColdFire UART driver 5 * 6 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com> 7 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw> 8 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/interrupt.h> 19 #include <linux/module.h> 20 #include <linux/console.h> 21 #include <linux/of.h> 22 #include <linux/tty.h> 23 #include <linux/tty_flip.h> 24 #include <linux/serial.h> 25 #include <linux/serial_core.h> 26 #include <linux/platform_device.h> 27 #include <linux/io.h> 28 #include <linux/altera_jtaguart.h> 29 30 #define DRV_NAME "altera_jtaguart" 31 32 /* 33 * Altera JTAG UART register definitions according to the Altera JTAG UART 34 * datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf 35 */ 36 37 #define ALTERA_JTAGUART_SIZE 8 38 39 #define ALTERA_JTAGUART_DATA_REG 0 40 41 #define ALTERA_JTAGUART_DATA_DATA_MSK 0x000000FF 42 #define ALTERA_JTAGUART_DATA_RVALID_MSK 0x00008000 43 #define ALTERA_JTAGUART_DATA_RAVAIL_MSK 0xFFFF0000 44 #define ALTERA_JTAGUART_DATA_RAVAIL_OFF 16 45 46 #define ALTERA_JTAGUART_CONTROL_REG 4 47 48 #define ALTERA_JTAGUART_CONTROL_RE_MSK 0x00000001 49 #define ALTERA_JTAGUART_CONTROL_WE_MSK 0x00000002 50 #define ALTERA_JTAGUART_CONTROL_RI_MSK 0x00000100 51 #define ALTERA_JTAGUART_CONTROL_RI_OFF 8 52 #define ALTERA_JTAGUART_CONTROL_WI_MSK 0x00000200 53 #define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400 54 #define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000 55 #define ALTERA_JTAGUART_CONTROL_WSPACE_OFF 16 56 57 /* 58 * Local per-uart structure. 59 */ 60 struct altera_jtaguart { 61 struct uart_port port; 62 unsigned int sigs; /* Local copy of line sigs */ 63 unsigned long imr; /* Local IMR mirror */ 64 }; 65 66 static unsigned int altera_jtaguart_tx_empty(struct uart_port *port) 67 { 68 return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & 69 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0; 70 } 71 72 static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port) 73 { 74 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; 75 } 76 77 static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs) 78 { 79 } 80 81 static void altera_jtaguart_start_tx(struct uart_port *port) 82 { 83 struct altera_jtaguart *pp = 84 container_of(port, struct altera_jtaguart, port); 85 86 pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK; 87 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 88 } 89 90 static void altera_jtaguart_stop_tx(struct uart_port *port) 91 { 92 struct altera_jtaguart *pp = 93 container_of(port, struct altera_jtaguart, port); 94 95 pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK; 96 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 97 } 98 99 static void altera_jtaguart_stop_rx(struct uart_port *port) 100 { 101 struct altera_jtaguart *pp = 102 container_of(port, struct altera_jtaguart, port); 103 104 pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK; 105 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 106 } 107 108 static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state) 109 { 110 } 111 112 static void altera_jtaguart_set_termios(struct uart_port *port, 113 struct ktermios *termios, 114 struct ktermios *old) 115 { 116 /* Just copy the old termios settings back */ 117 if (old) 118 tty_termios_copy_hw(termios, old); 119 } 120 121 static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp) 122 { 123 struct uart_port *port = &pp->port; 124 unsigned char ch, flag; 125 unsigned long status; 126 127 while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) & 128 ALTERA_JTAGUART_DATA_RVALID_MSK) { 129 ch = status & ALTERA_JTAGUART_DATA_DATA_MSK; 130 flag = TTY_NORMAL; 131 port->icount.rx++; 132 133 if (uart_handle_sysrq_char(port, ch)) 134 continue; 135 uart_insert_char(port, 0, 0, ch, flag); 136 } 137 138 spin_unlock(&port->lock); 139 tty_flip_buffer_push(&port->state->port); 140 spin_lock(&port->lock); 141 } 142 143 static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp) 144 { 145 struct uart_port *port = &pp->port; 146 struct circ_buf *xmit = &port->state->xmit; 147 unsigned int pending, count; 148 149 if (port->x_char) { 150 /* Send special char - probably flow control */ 151 writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG); 152 port->x_char = 0; 153 port->icount.tx++; 154 return; 155 } 156 157 pending = uart_circ_chars_pending(xmit); 158 if (pending > 0) { 159 count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & 160 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >> 161 ALTERA_JTAGUART_CONTROL_WSPACE_OFF; 162 if (count > pending) 163 count = pending; 164 if (count > 0) { 165 pending -= count; 166 while (count--) { 167 writel(xmit->buf[xmit->tail], 168 port->membase + ALTERA_JTAGUART_DATA_REG); 169 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 170 port->icount.tx++; 171 } 172 if (pending < WAKEUP_CHARS) 173 uart_write_wakeup(port); 174 } 175 } 176 177 if (pending == 0) { 178 pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK; 179 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 180 } 181 } 182 183 static irqreturn_t altera_jtaguart_interrupt(int irq, void *data) 184 { 185 struct uart_port *port = data; 186 struct altera_jtaguart *pp = 187 container_of(port, struct altera_jtaguart, port); 188 unsigned int isr; 189 190 isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> 191 ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr; 192 193 spin_lock(&port->lock); 194 195 if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) 196 altera_jtaguart_rx_chars(pp); 197 if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) 198 altera_jtaguart_tx_chars(pp); 199 200 spin_unlock(&port->lock); 201 202 return IRQ_RETVAL(isr); 203 } 204 205 static void altera_jtaguart_config_port(struct uart_port *port, int flags) 206 { 207 port->type = PORT_ALTERA_JTAGUART; 208 209 /* Clear mask, so no surprise interrupts. */ 210 writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG); 211 } 212 213 static int altera_jtaguart_startup(struct uart_port *port) 214 { 215 struct altera_jtaguart *pp = 216 container_of(port, struct altera_jtaguart, port); 217 unsigned long flags; 218 int ret; 219 220 ret = request_irq(port->irq, altera_jtaguart_interrupt, 0, 221 DRV_NAME, port); 222 if (ret) { 223 pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d " 224 "interrupt vector=%d\n", port->line, port->irq); 225 return ret; 226 } 227 228 spin_lock_irqsave(&port->lock, flags); 229 230 /* Enable RX interrupts now */ 231 pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK; 232 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 233 234 spin_unlock_irqrestore(&port->lock, flags); 235 236 return 0; 237 } 238 239 static void altera_jtaguart_shutdown(struct uart_port *port) 240 { 241 struct altera_jtaguart *pp = 242 container_of(port, struct altera_jtaguart, port); 243 unsigned long flags; 244 245 spin_lock_irqsave(&port->lock, flags); 246 247 /* Disable all interrupts now */ 248 pp->imr = 0; 249 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG); 250 251 spin_unlock_irqrestore(&port->lock, flags); 252 253 free_irq(port->irq, port); 254 } 255 256 static const char *altera_jtaguart_type(struct uart_port *port) 257 { 258 return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL; 259 } 260 261 static int altera_jtaguart_request_port(struct uart_port *port) 262 { 263 /* UARTs always present */ 264 return 0; 265 } 266 267 static void altera_jtaguart_release_port(struct uart_port *port) 268 { 269 /* Nothing to release... */ 270 } 271 272 static int altera_jtaguart_verify_port(struct uart_port *port, 273 struct serial_struct *ser) 274 { 275 if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART) 276 return -EINVAL; 277 return 0; 278 } 279 280 /* 281 * Define the basic serial functions we support. 282 */ 283 static struct uart_ops altera_jtaguart_ops = { 284 .tx_empty = altera_jtaguart_tx_empty, 285 .get_mctrl = altera_jtaguart_get_mctrl, 286 .set_mctrl = altera_jtaguart_set_mctrl, 287 .start_tx = altera_jtaguart_start_tx, 288 .stop_tx = altera_jtaguart_stop_tx, 289 .stop_rx = altera_jtaguart_stop_rx, 290 .break_ctl = altera_jtaguart_break_ctl, 291 .startup = altera_jtaguart_startup, 292 .shutdown = altera_jtaguart_shutdown, 293 .set_termios = altera_jtaguart_set_termios, 294 .type = altera_jtaguart_type, 295 .request_port = altera_jtaguart_request_port, 296 .release_port = altera_jtaguart_release_port, 297 .config_port = altera_jtaguart_config_port, 298 .verify_port = altera_jtaguart_verify_port, 299 }; 300 301 #define ALTERA_JTAGUART_MAXPORTS 1 302 static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS]; 303 304 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE) 305 306 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS) 307 static void altera_jtaguart_console_putc(struct uart_port *port, int c) 308 { 309 unsigned long status; 310 unsigned long flags; 311 312 spin_lock_irqsave(&port->lock, flags); 313 while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) & 314 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) { 315 if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { 316 spin_unlock_irqrestore(&port->lock, flags); 317 return; /* no connection activity */ 318 } 319 spin_unlock_irqrestore(&port->lock, flags); 320 cpu_relax(); 321 spin_lock_irqsave(&port->lock, flags); 322 } 323 writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); 324 spin_unlock_irqrestore(&port->lock, flags); 325 } 326 #else 327 static void altera_jtaguart_console_putc(struct uart_port *port, int c) 328 { 329 unsigned long flags; 330 331 spin_lock_irqsave(&port->lock, flags); 332 while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) & 333 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) { 334 spin_unlock_irqrestore(&port->lock, flags); 335 cpu_relax(); 336 spin_lock_irqsave(&port->lock, flags); 337 } 338 writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); 339 spin_unlock_irqrestore(&port->lock, flags); 340 } 341 #endif 342 343 static void altera_jtaguart_console_write(struct console *co, const char *s, 344 unsigned int count) 345 { 346 struct uart_port *port = &(altera_jtaguart_ports + co->index)->port; 347 348 uart_console_write(port, s, count, altera_jtaguart_console_putc); 349 } 350 351 static int __init altera_jtaguart_console_setup(struct console *co, 352 char *options) 353 { 354 struct uart_port *port; 355 356 if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS) 357 return -EINVAL; 358 port = &altera_jtaguart_ports[co->index].port; 359 if (port->membase == NULL) 360 return -ENODEV; 361 return 0; 362 } 363 364 static struct uart_driver altera_jtaguart_driver; 365 366 static struct console altera_jtaguart_console = { 367 .name = "ttyJ", 368 .write = altera_jtaguart_console_write, 369 .device = uart_console_device, 370 .setup = altera_jtaguart_console_setup, 371 .flags = CON_PRINTBUFFER, 372 .index = -1, 373 .data = &altera_jtaguart_driver, 374 }; 375 376 static int __init altera_jtaguart_console_init(void) 377 { 378 register_console(&altera_jtaguart_console); 379 return 0; 380 } 381 382 console_initcall(altera_jtaguart_console_init); 383 384 #define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console) 385 386 #else 387 388 #define ALTERA_JTAGUART_CONSOLE NULL 389 390 #endif /* CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE */ 391 392 static struct uart_driver altera_jtaguart_driver = { 393 .owner = THIS_MODULE, 394 .driver_name = "altera_jtaguart", 395 .dev_name = "ttyJ", 396 .major = ALTERA_JTAGUART_MAJOR, 397 .minor = ALTERA_JTAGUART_MINOR, 398 .nr = ALTERA_JTAGUART_MAXPORTS, 399 .cons = ALTERA_JTAGUART_CONSOLE, 400 }; 401 402 static int altera_jtaguart_probe(struct platform_device *pdev) 403 { 404 struct altera_jtaguart_platform_uart *platp = 405 dev_get_platdata(&pdev->dev); 406 struct uart_port *port; 407 struct resource *res_irq, *res_mem; 408 int i = pdev->id; 409 410 /* -1 emphasizes that the platform must have one port, no .N suffix */ 411 if (i == -1) 412 i = 0; 413 414 if (i >= ALTERA_JTAGUART_MAXPORTS) 415 return -EINVAL; 416 417 port = &altera_jtaguart_ports[i].port; 418 419 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 420 if (res_mem) 421 port->mapbase = res_mem->start; 422 else if (platp) 423 port->mapbase = platp->mapbase; 424 else 425 return -ENODEV; 426 427 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 428 if (res_irq) 429 port->irq = res_irq->start; 430 else if (platp) 431 port->irq = platp->irq; 432 else 433 return -ENODEV; 434 435 port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE); 436 if (!port->membase) 437 return -ENOMEM; 438 439 port->line = i; 440 port->type = PORT_ALTERA_JTAGUART; 441 port->iotype = SERIAL_IO_MEM; 442 port->ops = &altera_jtaguart_ops; 443 port->flags = UPF_BOOT_AUTOCONF; 444 port->dev = &pdev->dev; 445 446 uart_add_one_port(&altera_jtaguart_driver, port); 447 448 return 0; 449 } 450 451 static int altera_jtaguart_remove(struct platform_device *pdev) 452 { 453 struct uart_port *port; 454 int i = pdev->id; 455 456 if (i == -1) 457 i = 0; 458 459 port = &altera_jtaguart_ports[i].port; 460 uart_remove_one_port(&altera_jtaguart_driver, port); 461 462 return 0; 463 } 464 465 #ifdef CONFIG_OF 466 static const struct of_device_id altera_jtaguart_match[] = { 467 { .compatible = "ALTR,juart-1.0", }, 468 { .compatible = "altr,juart-1.0", }, 469 {}, 470 }; 471 MODULE_DEVICE_TABLE(of, altera_jtaguart_match); 472 #endif /* CONFIG_OF */ 473 474 static struct platform_driver altera_jtaguart_platform_driver = { 475 .probe = altera_jtaguart_probe, 476 .remove = altera_jtaguart_remove, 477 .driver = { 478 .name = DRV_NAME, 479 .of_match_table = of_match_ptr(altera_jtaguart_match), 480 }, 481 }; 482 483 static int __init altera_jtaguart_init(void) 484 { 485 int rc; 486 487 rc = uart_register_driver(&altera_jtaguart_driver); 488 if (rc) 489 return rc; 490 rc = platform_driver_register(&altera_jtaguart_platform_driver); 491 if (rc) 492 uart_unregister_driver(&altera_jtaguart_driver); 493 return rc; 494 } 495 496 static void __exit altera_jtaguart_exit(void) 497 { 498 platform_driver_unregister(&altera_jtaguart_platform_driver); 499 uart_unregister_driver(&altera_jtaguart_driver); 500 } 501 502 module_init(altera_jtaguart_init); 503 module_exit(altera_jtaguart_exit); 504 505 MODULE_DESCRIPTION("Altera JTAG UART driver"); 506 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); 507 MODULE_LICENSE("GPL"); 508 MODULE_ALIAS("platform:" DRV_NAME); 509