xref: /linux/drivers/tty/serial/lpc32xx_hs.c (revision ff5599816711d2e67da2d7561fd36ac48debd433)
1 /*
2  * High Speed Serial Ports on NXP LPC32xx SoC
3  *
4  * Authors: Kevin Wells <kevin.wells@nxp.com>
5  *          Roland Stigge <stigge@antcom.de>
6  *
7  * Copyright (C) 2010 NXP Semiconductors
8  * Copyright (C) 2012 Roland Stigge
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  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  */
20 
21 #include <linux/module.h>
22 #include <linux/ioport.h>
23 #include <linux/init.h>
24 #include <linux/console.h>
25 #include <linux/sysrq.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
28 #include <linux/serial_core.h>
29 #include <linux/serial.h>
30 #include <linux/platform_device.h>
31 #include <linux/delay.h>
32 #include <linux/nmi.h>
33 #include <linux/io.h>
34 #include <linux/irq.h>
35 #include <linux/gpio.h>
36 #include <linux/of.h>
37 #include <mach/platform.h>
38 #include <mach/hardware.h>
39 
40 /*
41  * High Speed UART register offsets
42  */
43 #define LPC32XX_HSUART_FIFO(x)			((x) + 0x00)
44 #define LPC32XX_HSUART_LEVEL(x)			((x) + 0x04)
45 #define LPC32XX_HSUART_IIR(x)			((x) + 0x08)
46 #define LPC32XX_HSUART_CTRL(x)			((x) + 0x0C)
47 #define LPC32XX_HSUART_RATE(x)			((x) + 0x10)
48 
49 #define LPC32XX_HSU_BREAK_DATA			(1 << 10)
50 #define LPC32XX_HSU_ERROR_DATA			(1 << 9)
51 #define LPC32XX_HSU_RX_EMPTY			(1 << 8)
52 
53 #define LPC32XX_HSU_TX_LEV(n)			(((n) >> 8) & 0xFF)
54 #define LPC32XX_HSU_RX_LEV(n)			((n) & 0xFF)
55 
56 #define LPC32XX_HSU_TX_INT_SET			(1 << 6)
57 #define LPC32XX_HSU_RX_OE_INT			(1 << 5)
58 #define LPC32XX_HSU_BRK_INT			(1 << 4)
59 #define LPC32XX_HSU_FE_INT			(1 << 3)
60 #define LPC32XX_HSU_RX_TIMEOUT_INT		(1 << 2)
61 #define LPC32XX_HSU_RX_TRIG_INT			(1 << 1)
62 #define LPC32XX_HSU_TX_INT			(1 << 0)
63 
64 #define LPC32XX_HSU_HRTS_INV			(1 << 21)
65 #define LPC32XX_HSU_HRTS_TRIG_8B		(0x0 << 19)
66 #define LPC32XX_HSU_HRTS_TRIG_16B		(0x1 << 19)
67 #define LPC32XX_HSU_HRTS_TRIG_32B		(0x2 << 19)
68 #define LPC32XX_HSU_HRTS_TRIG_48B		(0x3 << 19)
69 #define LPC32XX_HSU_HRTS_EN			(1 << 18)
70 #define LPC32XX_HSU_TMO_DISABLED		(0x0 << 16)
71 #define LPC32XX_HSU_TMO_INACT_4B		(0x1 << 16)
72 #define LPC32XX_HSU_TMO_INACT_8B		(0x2 << 16)
73 #define LPC32XX_HSU_TMO_INACT_16B		(0x3 << 16)
74 #define LPC32XX_HSU_HCTS_INV			(1 << 15)
75 #define LPC32XX_HSU_HCTS_EN			(1 << 14)
76 #define LPC32XX_HSU_OFFSET(n)			((n) << 9)
77 #define LPC32XX_HSU_BREAK			(1 << 8)
78 #define LPC32XX_HSU_ERR_INT_EN			(1 << 7)
79 #define LPC32XX_HSU_RX_INT_EN			(1 << 6)
80 #define LPC32XX_HSU_TX_INT_EN			(1 << 5)
81 #define LPC32XX_HSU_RX_TL1B			(0x0 << 2)
82 #define LPC32XX_HSU_RX_TL4B			(0x1 << 2)
83 #define LPC32XX_HSU_RX_TL8B			(0x2 << 2)
84 #define LPC32XX_HSU_RX_TL16B			(0x3 << 2)
85 #define LPC32XX_HSU_RX_TL32B			(0x4 << 2)
86 #define LPC32XX_HSU_RX_TL48B			(0x5 << 2)
87 #define LPC32XX_HSU_TX_TLEMPTY			(0x0 << 0)
88 #define LPC32XX_HSU_TX_TL0B			(0x0 << 0)
89 #define LPC32XX_HSU_TX_TL4B			(0x1 << 0)
90 #define LPC32XX_HSU_TX_TL8B			(0x2 << 0)
91 #define LPC32XX_HSU_TX_TL16B			(0x3 << 0)
92 
93 #define MODNAME "lpc32xx_hsuart"
94 
95 struct lpc32xx_hsuart_port {
96 	struct uart_port port;
97 };
98 
99 #define FIFO_READ_LIMIT 128
100 #define MAX_PORTS 3
101 #define LPC32XX_TTY_NAME "ttyTX"
102 static struct lpc32xx_hsuart_port lpc32xx_hs_ports[MAX_PORTS];
103 
104 #ifdef CONFIG_SERIAL_HS_LPC32XX_CONSOLE
105 static void wait_for_xmit_empty(struct uart_port *port)
106 {
107 	unsigned int timeout = 10000;
108 
109 	do {
110 		if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(
111 							port->membase))) == 0)
112 			break;
113 		if (--timeout == 0)
114 			break;
115 		udelay(1);
116 	} while (1);
117 }
118 
119 static void wait_for_xmit_ready(struct uart_port *port)
120 {
121 	unsigned int timeout = 10000;
122 
123 	while (1) {
124 		if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(
125 							port->membase))) < 32)
126 			break;
127 		if (--timeout == 0)
128 			break;
129 		udelay(1);
130 	}
131 }
132 
133 static void lpc32xx_hsuart_console_putchar(struct uart_port *port, int ch)
134 {
135 	wait_for_xmit_ready(port);
136 	writel((u32)ch, LPC32XX_HSUART_FIFO(port->membase));
137 }
138 
139 static void lpc32xx_hsuart_console_write(struct console *co, const char *s,
140 					 unsigned int count)
141 {
142 	struct lpc32xx_hsuart_port *up = &lpc32xx_hs_ports[co->index];
143 	unsigned long flags;
144 	int locked = 1;
145 
146 	touch_nmi_watchdog();
147 	local_irq_save(flags);
148 	if (up->port.sysrq)
149 		locked = 0;
150 	else if (oops_in_progress)
151 		locked = spin_trylock(&up->port.lock);
152 	else
153 		spin_lock(&up->port.lock);
154 
155 	uart_console_write(&up->port, s, count, lpc32xx_hsuart_console_putchar);
156 	wait_for_xmit_empty(&up->port);
157 
158 	if (locked)
159 		spin_unlock(&up->port.lock);
160 	local_irq_restore(flags);
161 }
162 
163 static int __init lpc32xx_hsuart_console_setup(struct console *co,
164 					       char *options)
165 {
166 	struct uart_port *port;
167 	int baud = 115200;
168 	int bits = 8;
169 	int parity = 'n';
170 	int flow = 'n';
171 
172 	if (co->index >= MAX_PORTS)
173 		co->index = 0;
174 
175 	port = &lpc32xx_hs_ports[co->index].port;
176 	if (!port->membase)
177 		return -ENODEV;
178 
179 	if (options)
180 		uart_parse_options(options, &baud, &parity, &bits, &flow);
181 
182 	return uart_set_options(port, co, baud, parity, bits, flow);
183 }
184 
185 static struct uart_driver lpc32xx_hsuart_reg;
186 static struct console lpc32xx_hsuart_console = {
187 	.name		= LPC32XX_TTY_NAME,
188 	.write		= lpc32xx_hsuart_console_write,
189 	.device		= uart_console_device,
190 	.setup		= lpc32xx_hsuart_console_setup,
191 	.flags		= CON_PRINTBUFFER,
192 	.index		= -1,
193 	.data		= &lpc32xx_hsuart_reg,
194 };
195 
196 static int __init lpc32xx_hsuart_console_init(void)
197 {
198 	register_console(&lpc32xx_hsuart_console);
199 	return 0;
200 }
201 console_initcall(lpc32xx_hsuart_console_init);
202 
203 #define LPC32XX_HSUART_CONSOLE (&lpc32xx_hsuart_console)
204 #else
205 #define LPC32XX_HSUART_CONSOLE NULL
206 #endif
207 
208 static struct uart_driver lpc32xx_hs_reg = {
209 	.owner		= THIS_MODULE,
210 	.driver_name	= MODNAME,
211 	.dev_name	= LPC32XX_TTY_NAME,
212 	.nr		= MAX_PORTS,
213 	.cons		= LPC32XX_HSUART_CONSOLE,
214 };
215 static int uarts_registered;
216 
217 static unsigned int __serial_get_clock_div(unsigned long uartclk,
218 					   unsigned long rate)
219 {
220 	u32 div, goodrate, hsu_rate, l_hsu_rate, comprate;
221 	u32 rate_diff;
222 
223 	/* Find the closest divider to get the desired clock rate */
224 	div = uartclk / rate;
225 	goodrate = hsu_rate = (div / 14) - 1;
226 	if (hsu_rate != 0)
227 		hsu_rate--;
228 
229 	/* Tweak divider */
230 	l_hsu_rate = hsu_rate + 3;
231 	rate_diff = 0xFFFFFFFF;
232 
233 	while (hsu_rate < l_hsu_rate) {
234 		comprate = uartclk / ((hsu_rate + 1) * 14);
235 		if (abs(comprate - rate) < rate_diff) {
236 			goodrate = hsu_rate;
237 			rate_diff = abs(comprate - rate);
238 		}
239 
240 		hsu_rate++;
241 	}
242 	if (hsu_rate > 0xFF)
243 		hsu_rate = 0xFF;
244 
245 	return goodrate;
246 }
247 
248 static void __serial_uart_flush(struct uart_port *port)
249 {
250 	u32 tmp;
251 	int cnt = 0;
252 
253 	while ((readl(LPC32XX_HSUART_LEVEL(port->membase)) > 0) &&
254 	       (cnt++ < FIFO_READ_LIMIT))
255 		tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
256 }
257 
258 static void __serial_lpc32xx_rx(struct uart_port *port)
259 {
260 	struct tty_port *tport = &port->state->port;
261 	unsigned int tmp, flag;
262 
263 	/* Read data from FIFO and push into terminal */
264 	tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
265 	while (!(tmp & LPC32XX_HSU_RX_EMPTY)) {
266 		flag = TTY_NORMAL;
267 		port->icount.rx++;
268 
269 		if (tmp & LPC32XX_HSU_ERROR_DATA) {
270 			/* Framing error */
271 			writel(LPC32XX_HSU_FE_INT,
272 			       LPC32XX_HSUART_IIR(port->membase));
273 			port->icount.frame++;
274 			flag = TTY_FRAME;
275 			tty_insert_flip_char(tport, 0, TTY_FRAME);
276 		}
277 
278 		tty_insert_flip_char(tport, (tmp & 0xFF), flag);
279 
280 		tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
281 	}
282 	tty_flip_buffer_push(tport);
283 }
284 
285 static void __serial_lpc32xx_tx(struct uart_port *port)
286 {
287 	struct circ_buf *xmit = &port->state->xmit;
288 	unsigned int tmp;
289 
290 	if (port->x_char) {
291 		writel((u32)port->x_char, LPC32XX_HSUART_FIFO(port->membase));
292 		port->icount.tx++;
293 		port->x_char = 0;
294 		return;
295 	}
296 
297 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
298 		goto exit_tx;
299 
300 	/* Transfer data */
301 	while (LPC32XX_HSU_TX_LEV(readl(
302 		LPC32XX_HSUART_LEVEL(port->membase))) < 64) {
303 		writel((u32) xmit->buf[xmit->tail],
304 		       LPC32XX_HSUART_FIFO(port->membase));
305 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
306 		port->icount.tx++;
307 		if (uart_circ_empty(xmit))
308 			break;
309 	}
310 
311 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
312 		uart_write_wakeup(port);
313 
314 exit_tx:
315 	if (uart_circ_empty(xmit)) {
316 		tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
317 		tmp &= ~LPC32XX_HSU_TX_INT_EN;
318 		writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
319 	}
320 }
321 
322 static irqreturn_t serial_lpc32xx_interrupt(int irq, void *dev_id)
323 {
324 	struct uart_port *port = dev_id;
325 	struct tty_port *tport = &port->state->port;
326 	u32 status;
327 
328 	spin_lock(&port->lock);
329 
330 	/* Read UART status and clear latched interrupts */
331 	status = readl(LPC32XX_HSUART_IIR(port->membase));
332 
333 	if (status & LPC32XX_HSU_BRK_INT) {
334 		/* Break received */
335 		writel(LPC32XX_HSU_BRK_INT, LPC32XX_HSUART_IIR(port->membase));
336 		port->icount.brk++;
337 		uart_handle_break(port);
338 	}
339 
340 	/* Framing error */
341 	if (status & LPC32XX_HSU_FE_INT)
342 		writel(LPC32XX_HSU_FE_INT, LPC32XX_HSUART_IIR(port->membase));
343 
344 	if (status & LPC32XX_HSU_RX_OE_INT) {
345 		/* Receive FIFO overrun */
346 		writel(LPC32XX_HSU_RX_OE_INT,
347 		       LPC32XX_HSUART_IIR(port->membase));
348 		port->icount.overrun++;
349 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
350 		tty_schedule_flip(tport);
351 	}
352 
353 	/* Data received? */
354 	if (status & (LPC32XX_HSU_RX_TIMEOUT_INT | LPC32XX_HSU_RX_TRIG_INT)) {
355 		__serial_lpc32xx_rx(port);
356 		tty_flip_buffer_push(tport);
357 	}
358 
359 	/* Transmit data request? */
360 	if ((status & LPC32XX_HSU_TX_INT) && (!uart_tx_stopped(port))) {
361 		writel(LPC32XX_HSU_TX_INT, LPC32XX_HSUART_IIR(port->membase));
362 		__serial_lpc32xx_tx(port);
363 	}
364 
365 	spin_unlock(&port->lock);
366 
367 	return IRQ_HANDLED;
368 }
369 
370 /* port->lock is not held.  */
371 static unsigned int serial_lpc32xx_tx_empty(struct uart_port *port)
372 {
373 	unsigned int ret = 0;
374 
375 	if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(port->membase))) == 0)
376 		ret = TIOCSER_TEMT;
377 
378 	return ret;
379 }
380 
381 /* port->lock held by caller.  */
382 static void serial_lpc32xx_set_mctrl(struct uart_port *port,
383 				     unsigned int mctrl)
384 {
385 	/* No signals are supported on HS UARTs */
386 }
387 
388 /* port->lock is held by caller and interrupts are disabled.  */
389 static unsigned int serial_lpc32xx_get_mctrl(struct uart_port *port)
390 {
391 	/* No signals are supported on HS UARTs */
392 	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
393 }
394 
395 /* port->lock held by caller.  */
396 static void serial_lpc32xx_stop_tx(struct uart_port *port)
397 {
398 	u32 tmp;
399 
400 	tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
401 	tmp &= ~LPC32XX_HSU_TX_INT_EN;
402 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
403 }
404 
405 /* port->lock held by caller.  */
406 static void serial_lpc32xx_start_tx(struct uart_port *port)
407 {
408 	u32 tmp;
409 
410 	__serial_lpc32xx_tx(port);
411 	tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
412 	tmp |= LPC32XX_HSU_TX_INT_EN;
413 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
414 }
415 
416 /* port->lock held by caller.  */
417 static void serial_lpc32xx_stop_rx(struct uart_port *port)
418 {
419 	u32 tmp;
420 
421 	tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
422 	tmp &= ~(LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN);
423 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
424 
425 	writel((LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT |
426 		LPC32XX_HSU_FE_INT), LPC32XX_HSUART_IIR(port->membase));
427 }
428 
429 /* port->lock held by caller.  */
430 static void serial_lpc32xx_enable_ms(struct uart_port *port)
431 {
432 	/* Modem status is not supported */
433 }
434 
435 /* port->lock is not held.  */
436 static void serial_lpc32xx_break_ctl(struct uart_port *port,
437 				     int break_state)
438 {
439 	unsigned long flags;
440 	u32 tmp;
441 
442 	spin_lock_irqsave(&port->lock, flags);
443 	tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
444 	if (break_state != 0)
445 		tmp |= LPC32XX_HSU_BREAK;
446 	else
447 		tmp &= ~LPC32XX_HSU_BREAK;
448 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
449 	spin_unlock_irqrestore(&port->lock, flags);
450 }
451 
452 /* LPC3250 Errata HSUART.1: Hang workaround via loopback mode on inactivity */
453 static void lpc32xx_loopback_set(resource_size_t mapbase, int state)
454 {
455 	int bit;
456 	u32 tmp;
457 
458 	switch (mapbase) {
459 	case LPC32XX_HS_UART1_BASE:
460 		bit = 0;
461 		break;
462 	case LPC32XX_HS_UART2_BASE:
463 		bit = 1;
464 		break;
465 	case LPC32XX_HS_UART7_BASE:
466 		bit = 6;
467 		break;
468 	default:
469 		WARN(1, "lpc32xx_hs: Warning: Unknown port at %08x\n", mapbase);
470 		return;
471 	}
472 
473 	tmp = readl(LPC32XX_UARTCTL_CLOOP);
474 	if (state)
475 		tmp |= (1 << bit);
476 	else
477 		tmp &= ~(1 << bit);
478 	writel(tmp, LPC32XX_UARTCTL_CLOOP);
479 }
480 
481 /* port->lock is not held.  */
482 static int serial_lpc32xx_startup(struct uart_port *port)
483 {
484 	int retval;
485 	unsigned long flags;
486 	u32 tmp;
487 
488 	spin_lock_irqsave(&port->lock, flags);
489 
490 	__serial_uart_flush(port);
491 
492 	writel((LPC32XX_HSU_TX_INT | LPC32XX_HSU_FE_INT |
493 		LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT),
494 	       LPC32XX_HSUART_IIR(port->membase));
495 
496 	writel(0xFF, LPC32XX_HSUART_RATE(port->membase));
497 
498 	/*
499 	 * Set receiver timeout, HSU offset of 20, no break, no interrupts,
500 	 * and default FIFO trigger levels
501 	 */
502 	tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
503 		LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B;
504 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
505 
506 	lpc32xx_loopback_set(port->mapbase, 0); /* get out of loopback mode */
507 
508 	spin_unlock_irqrestore(&port->lock, flags);
509 
510 	retval = request_irq(port->irq, serial_lpc32xx_interrupt,
511 			     0, MODNAME, port);
512 	if (!retval)
513 		writel((tmp | LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN),
514 		       LPC32XX_HSUART_CTRL(port->membase));
515 
516 	return retval;
517 }
518 
519 /* port->lock is not held.  */
520 static void serial_lpc32xx_shutdown(struct uart_port *port)
521 {
522 	u32 tmp;
523 	unsigned long flags;
524 
525 	spin_lock_irqsave(&port->lock, flags);
526 
527 	tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
528 		LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B;
529 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
530 
531 	lpc32xx_loopback_set(port->mapbase, 1); /* go to loopback mode */
532 
533 	spin_unlock_irqrestore(&port->lock, flags);
534 
535 	free_irq(port->irq, port);
536 }
537 
538 /* port->lock is not held.  */
539 static void serial_lpc32xx_set_termios(struct uart_port *port,
540 				       struct ktermios *termios,
541 				       struct ktermios *old)
542 {
543 	unsigned long flags;
544 	unsigned int baud, quot;
545 	u32 tmp;
546 
547 	/* Always 8-bit, no parity, 1 stop bit */
548 	termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD);
549 	termios->c_cflag |= CS8;
550 
551 	termios->c_cflag &= ~(HUPCL | CMSPAR | CLOCAL | CRTSCTS);
552 
553 	baud = uart_get_baud_rate(port, termios, old, 0,
554 				  port->uartclk / 14);
555 
556 	quot = __serial_get_clock_div(port->uartclk, baud);
557 
558 	spin_lock_irqsave(&port->lock, flags);
559 
560 	/* Ignore characters? */
561 	tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
562 	if ((termios->c_cflag & CREAD) == 0)
563 		tmp &= ~(LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN);
564 	else
565 		tmp |= LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN;
566 	writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
567 
568 	writel(quot, LPC32XX_HSUART_RATE(port->membase));
569 
570 	uart_update_timeout(port, termios->c_cflag, baud);
571 
572 	spin_unlock_irqrestore(&port->lock, flags);
573 
574 	/* Don't rewrite B0 */
575 	if (tty_termios_baud_rate(termios))
576 		tty_termios_encode_baud_rate(termios, baud, baud);
577 }
578 
579 static const char *serial_lpc32xx_type(struct uart_port *port)
580 {
581 	return MODNAME;
582 }
583 
584 static void serial_lpc32xx_release_port(struct uart_port *port)
585 {
586 	if ((port->iotype == UPIO_MEM32) && (port->mapbase)) {
587 		if (port->flags & UPF_IOREMAP) {
588 			iounmap(port->membase);
589 			port->membase = NULL;
590 		}
591 
592 		release_mem_region(port->mapbase, SZ_4K);
593 	}
594 }
595 
596 static int serial_lpc32xx_request_port(struct uart_port *port)
597 {
598 	int ret = -ENODEV;
599 
600 	if ((port->iotype == UPIO_MEM32) && (port->mapbase)) {
601 		ret = 0;
602 
603 		if (!request_mem_region(port->mapbase, SZ_4K, MODNAME))
604 			ret = -EBUSY;
605 		else if (port->flags & UPF_IOREMAP) {
606 			port->membase = ioremap(port->mapbase, SZ_4K);
607 			if (!port->membase) {
608 				release_mem_region(port->mapbase, SZ_4K);
609 				ret = -ENOMEM;
610 			}
611 		}
612 	}
613 
614 	return ret;
615 }
616 
617 static void serial_lpc32xx_config_port(struct uart_port *port, int uflags)
618 {
619 	int ret;
620 
621 	ret = serial_lpc32xx_request_port(port);
622 	if (ret < 0)
623 		return;
624 	port->type = PORT_UART00;
625 	port->fifosize = 64;
626 
627 	__serial_uart_flush(port);
628 
629 	writel((LPC32XX_HSU_TX_INT | LPC32XX_HSU_FE_INT |
630 		LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT),
631 	       LPC32XX_HSUART_IIR(port->membase));
632 
633 	writel(0xFF, LPC32XX_HSUART_RATE(port->membase));
634 
635 	/* Set receiver timeout, HSU offset of 20, no break, no interrupts,
636 	   and default FIFO trigger levels */
637 	writel(LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
638 	       LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B,
639 	       LPC32XX_HSUART_CTRL(port->membase));
640 }
641 
642 static int serial_lpc32xx_verify_port(struct uart_port *port,
643 				      struct serial_struct *ser)
644 {
645 	int ret = 0;
646 
647 	if (ser->type != PORT_UART00)
648 		ret = -EINVAL;
649 
650 	return ret;
651 }
652 
653 static struct uart_ops serial_lpc32xx_pops = {
654 	.tx_empty	= serial_lpc32xx_tx_empty,
655 	.set_mctrl	= serial_lpc32xx_set_mctrl,
656 	.get_mctrl	= serial_lpc32xx_get_mctrl,
657 	.stop_tx	= serial_lpc32xx_stop_tx,
658 	.start_tx	= serial_lpc32xx_start_tx,
659 	.stop_rx	= serial_lpc32xx_stop_rx,
660 	.enable_ms	= serial_lpc32xx_enable_ms,
661 	.break_ctl	= serial_lpc32xx_break_ctl,
662 	.startup	= serial_lpc32xx_startup,
663 	.shutdown	= serial_lpc32xx_shutdown,
664 	.set_termios	= serial_lpc32xx_set_termios,
665 	.type		= serial_lpc32xx_type,
666 	.release_port	= serial_lpc32xx_release_port,
667 	.request_port	= serial_lpc32xx_request_port,
668 	.config_port	= serial_lpc32xx_config_port,
669 	.verify_port	= serial_lpc32xx_verify_port,
670 };
671 
672 /*
673  * Register a set of serial devices attached to a platform device
674  */
675 static int serial_hs_lpc32xx_probe(struct platform_device *pdev)
676 {
677 	struct lpc32xx_hsuart_port *p = &lpc32xx_hs_ports[uarts_registered];
678 	int ret = 0;
679 	struct resource *res;
680 
681 	if (uarts_registered >= MAX_PORTS) {
682 		dev_err(&pdev->dev,
683 			"Error: Number of possible ports exceeded (%d)!\n",
684 			uarts_registered + 1);
685 		return -ENXIO;
686 	}
687 
688 	memset(p, 0, sizeof(*p));
689 
690 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
691 	if (!res) {
692 		dev_err(&pdev->dev,
693 			"Error getting mem resource for HS UART port %d\n",
694 			uarts_registered);
695 		return -ENXIO;
696 	}
697 	p->port.mapbase = res->start;
698 	p->port.membase = NULL;
699 
700 	p->port.irq = platform_get_irq(pdev, 0);
701 	if (p->port.irq < 0) {
702 		dev_err(&pdev->dev, "Error getting irq for HS UART port %d\n",
703 			uarts_registered);
704 		return p->port.irq;
705 	}
706 
707 	p->port.iotype = UPIO_MEM32;
708 	p->port.uartclk = LPC32XX_MAIN_OSC_FREQ;
709 	p->port.regshift = 2;
710 	p->port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP;
711 	p->port.dev = &pdev->dev;
712 	p->port.ops = &serial_lpc32xx_pops;
713 	p->port.line = uarts_registered++;
714 	spin_lock_init(&p->port.lock);
715 
716 	/* send port to loopback mode by default */
717 	lpc32xx_loopback_set(p->port.mapbase, 1);
718 
719 	ret = uart_add_one_port(&lpc32xx_hs_reg, &p->port);
720 
721 	platform_set_drvdata(pdev, p);
722 
723 	return ret;
724 }
725 
726 /*
727  * Remove serial ports registered against a platform device.
728  */
729 static int serial_hs_lpc32xx_remove(struct platform_device *pdev)
730 {
731 	struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
732 
733 	uart_remove_one_port(&lpc32xx_hs_reg, &p->port);
734 
735 	return 0;
736 }
737 
738 
739 #ifdef CONFIG_PM
740 static int serial_hs_lpc32xx_suspend(struct platform_device *pdev,
741 				     pm_message_t state)
742 {
743 	struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
744 
745 	uart_suspend_port(&lpc32xx_hs_reg, &p->port);
746 
747 	return 0;
748 }
749 
750 static int serial_hs_lpc32xx_resume(struct platform_device *pdev)
751 {
752 	struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
753 
754 	uart_resume_port(&lpc32xx_hs_reg, &p->port);
755 
756 	return 0;
757 }
758 #else
759 #define serial_hs_lpc32xx_suspend	NULL
760 #define serial_hs_lpc32xx_resume	NULL
761 #endif
762 
763 static const struct of_device_id serial_hs_lpc32xx_dt_ids[] = {
764 	{ .compatible = "nxp,lpc3220-hsuart" },
765 	{ /* sentinel */ }
766 };
767 
768 MODULE_DEVICE_TABLE(of, serial_hs_lpc32xx_dt_ids);
769 
770 static struct platform_driver serial_hs_lpc32xx_driver = {
771 	.probe		= serial_hs_lpc32xx_probe,
772 	.remove		= serial_hs_lpc32xx_remove,
773 	.suspend	= serial_hs_lpc32xx_suspend,
774 	.resume		= serial_hs_lpc32xx_resume,
775 	.driver		= {
776 		.name	= MODNAME,
777 		.owner	= THIS_MODULE,
778 		.of_match_table	= serial_hs_lpc32xx_dt_ids,
779 	},
780 };
781 
782 static int __init lpc32xx_hsuart_init(void)
783 {
784 	int ret;
785 
786 	ret = uart_register_driver(&lpc32xx_hs_reg);
787 	if (ret)
788 		return ret;
789 
790 	ret = platform_driver_register(&serial_hs_lpc32xx_driver);
791 	if (ret)
792 		uart_unregister_driver(&lpc32xx_hs_reg);
793 
794 	return ret;
795 }
796 
797 static void __exit lpc32xx_hsuart_exit(void)
798 {
799 	platform_driver_unregister(&serial_hs_lpc32xx_driver);
800 	uart_unregister_driver(&lpc32xx_hs_reg);
801 }
802 
803 module_init(lpc32xx_hsuart_init);
804 module_exit(lpc32xx_hsuart_exit);
805 
806 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
807 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
808 MODULE_DESCRIPTION("NXP LPC32XX High Speed UART driver");
809 MODULE_LICENSE("GPL");
810