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