xref: /freebsd/sys/arm/xilinx/uart_dev_cdnc.c (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005 Olivier Houchard All rights reserved.
5  * Copyright (c) 2012 Thomas Skibo All rights reserved.
6  * Copyright (c) 2005 M. Warner Losh <imp@FreeBSD.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 /* A driver for the Cadence AMBA UART as used by the Xilinx Zynq-7000.
32  *
33  * Reference: Zynq-7000 All Programmable SoC Technical Reference Manual.
34  * (v1.4) November 16, 2012.  Xilinx doc UG585.  UART is covered in Ch. 19
35  * and register definitions are in appendix B.33.
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/bus.h>
44 #include <sys/conf.h>
45 #include <sys/cons.h>
46 #include <machine/bus.h>
47 
48 #include <dev/uart/uart.h>
49 #include <dev/uart/uart_cpu.h>
50 #include <dev/uart/uart_cpu_fdt.h>
51 #include <dev/uart/uart_bus.h>
52 
53 #include "uart_if.h"
54 
55 #define	UART_FIFO_SIZE	64
56 
57 #define	RD4(bas, reg)		\
58 	bus_space_read_4((bas)->bst, (bas)->bsh, uart_regofs((bas), (reg)))
59 #define	WR4(bas, reg, value)	\
60 	bus_space_write_4((bas)->bst, (bas)->bsh, uart_regofs((bas), (reg)), \
61 			  (value))
62 
63 /* Register definitions for Cadence UART Controller.
64  */
65 #define CDNC_UART_CTRL_REG	0x00		/* Control Register. */
66 #define CDNC_UART_CTRL_REG_STOPBRK	(1<<8)
67 #define CDNC_UART_CTRL_REG_STARTBRK	(1<<7)
68 #define CDNC_UART_CTRL_REG_TORST	(1<<6)
69 #define CDNC_UART_CTRL_REG_TX_DIS	(1<<5)
70 #define CDNC_UART_CTRL_REG_TX_EN	(1<<4)
71 #define CDNC_UART_CTRL_REG_RX_DIS	(1<<3)
72 #define CDNC_UART_CTRL_REG_RX_EN	(1<<2)
73 #define CDNC_UART_CTRL_REG_TXRST	(1<<1)
74 #define CDNC_UART_CTRL_REG_RXRST	(1<<0)
75 
76 #define CDNC_UART_MODE_REG	0x04		/* Mode Register. */
77 #define CDNC_UART_MODE_REG_CHMOD_R_LOOP	(3<<8)	/* [9:8] - channel mode */
78 #define CDNC_UART_MODE_REG_CHMOD_L_LOOP	(2<<8)
79 #define CDNC_UART_MODE_REG_CHMOD_AUTECHO (1<<8)
80 #define CDNC_UART_MODE_REG_STOP2	(2<<6)	/* [7:6] - stop bits */
81 #define CDNC_UART_MODE_REG_PAR_NONE	(4<<3)	/* [5:3] - parity type */
82 #define CDNC_UART_MODE_REG_PAR_MARK	(3<<3)
83 #define CDNC_UART_MODE_REG_PAR_SPACE	(2<<3)
84 #define CDNC_UART_MODE_REG_PAR_ODD	(1<<3)
85 #define CDNC_UART_MODE_REG_PAR_EVEN	(0<<3)
86 #define CDNC_UART_MODE_REG_6BIT		(3<<1)	/* [2:1] - character len */
87 #define CDNC_UART_MODE_REG_7BIT		(2<<1)
88 #define CDNC_UART_MODE_REG_8BIT		(0<<1)
89 #define CDNC_UART_MODE_REG_CLKSEL	(1<<0)
90 
91 #define CDNC_UART_IEN_REG	0x08		/* Interrupt registers. */
92 #define CDNC_UART_IDIS_REG	0x0C
93 #define CDNC_UART_IMASK_REG	0x10
94 #define CDNC_UART_ISTAT_REG	0x14
95 #define CDNC_UART_INT_TXOVR		(1<<12)
96 #define CDNC_UART_INT_TXNRLYFUL		(1<<11)	/* tx "nearly" full */
97 #define CDNC_UART_INT_TXTRIG		(1<<10)
98 #define CDNC_UART_INT_DMSI		(1<<9)	/* delta modem status */
99 #define CDNC_UART_INT_RXTMOUT		(1<<8)
100 #define CDNC_UART_INT_PARITY		(1<<7)
101 #define CDNC_UART_INT_FRAMING		(1<<6)
102 #define CDNC_UART_INT_RXOVR		(1<<5)
103 #define CDNC_UART_INT_TXFULL		(1<<4)
104 #define CDNC_UART_INT_TXEMPTY		(1<<3)
105 #define CDNC_UART_INT_RXFULL		(1<<2)
106 #define CDNC_UART_INT_RXEMPTY		(1<<1)
107 #define CDNC_UART_INT_RXTRIG		(1<<0)
108 #define CDNC_UART_INT_ALL		0x1FFF
109 
110 #define CDNC_UART_BAUDGEN_REG	0x18
111 #define CDNC_UART_RX_TIMEO_REG	0x1C
112 #define CDNC_UART_RX_WATER_REG	0x20
113 
114 #define CDNC_UART_MODEM_CTRL_REG 0x24
115 #define CDNC_UART_MODEM_CTRL_REG_FCM	(1<<5)	/* automatic flow control */
116 #define CDNC_UART_MODEM_CTRL_REG_RTS	(1<<1)
117 #define CDNC_UART_MODEM_CTRL_REG_DTR	(1<<0)
118 
119 #define CDNC_UART_MODEM_STAT_REG 0x28
120 #define CDNC_UART_MODEM_STAT_REG_FCMS	(1<<8)	/* flow control mode (rw) */
121 #define CDNC_UART_MODEM_STAT_REG_DCD	(1<<7)
122 #define CDNC_UART_MODEM_STAT_REG_RI	(1<<6)
123 #define CDNC_UART_MODEM_STAT_REG_DSR	(1<<5)
124 #define CDNC_UART_MODEM_STAT_REG_CTS	(1<<4)
125 #define CDNC_UART_MODEM_STAT_REG_DDCD	(1<<3)	/* change in DCD (w1tc) */
126 #define CDNC_UART_MODEM_STAT_REG_TERI	(1<<2)	/* trail edge ring (w1tc) */
127 #define CDNC_UART_MODEM_STAT_REG_DDSR	(1<<1)	/* change in DSR (w1tc) */
128 #define CDNC_UART_MODEM_STAT_REG_DCTS	(1<<0)	/* change in CTS (w1tc) */
129 
130 #define CDNC_UART_CHAN_STAT_REG	0x2C		/* Channel status register. */
131 #define CDNC_UART_CHAN_STAT_REG_TXNRLYFUL (1<<14) /* tx "nearly" full */
132 #define CDNC_UART_CHAN_STAT_REG_TXTRIG	(1<<13)
133 #define CDNC_UART_CHAN_STAT_REG_FDELT	(1<<12)
134 #define CDNC_UART_CHAN_STAT_REG_TXACTIVE (1<<11)
135 #define CDNC_UART_CHAN_STAT_REG_RXACTIVE (1<<10)
136 #define CDNC_UART_CHAN_STAT_REG_TXFULL	(1<<4)
137 #define CDNC_UART_CHAN_STAT_REG_TXEMPTY	(1<<3)
138 #define CDNC_UART_CHAN_STAT_REG_RXEMPTY	(1<<1)
139 #define CDNC_UART_CHAN_STAT_REG_RXTRIG	(1<<0)
140 
141 #define CDNC_UART_FIFO		0x30		/* Data FIFO (tx and rx) */
142 #define CDNC_UART_BAUDDIV_REG	0x34
143 #define CDNC_UART_FLOWDEL_REG	0x38
144 #define CDNC_UART_TX_WATER_REG	0x44
145 
146 /*
147  * Low-level UART interface.
148  */
149 static int cdnc_uart_probe(struct uart_bas *bas);
150 static void cdnc_uart_init(struct uart_bas *bas, int, int, int, int);
151 static void cdnc_uart_term(struct uart_bas *bas);
152 static void cdnc_uart_putc(struct uart_bas *bas, int);
153 static int cdnc_uart_rxready(struct uart_bas *bas);
154 static int cdnc_uart_getc(struct uart_bas *bas, struct mtx *mtx);
155 
156 extern SLIST_HEAD(uart_devinfo_list, uart_devinfo) uart_sysdevs;
157 
158 static struct uart_ops cdnc_uart_ops = {
159 	.probe = cdnc_uart_probe,
160 	.init = cdnc_uart_init,
161 	.term = cdnc_uart_term,
162 	.putc = cdnc_uart_putc,
163 	.rxready = cdnc_uart_rxready,
164 	.getc = cdnc_uart_getc,
165 };
166 
167 #define	SIGCHG(c, i, s, d)				\
168 	if (c) {					\
169 		i |= (i & s) ? s : s | d;		\
170 	} else {					\
171 		i = (i & s) ? (i & ~s) | d : i;		\
172 	}
173 
174 static int
175 cdnc_uart_probe(struct uart_bas *bas)
176 {
177 
178 	return (0);
179 }
180 
181 static int
182 cdnc_uart_set_baud(struct uart_bas *bas, int baudrate)
183 {
184 	uint32_t baudgen, bauddiv;
185 	uint32_t best_bauddiv, best_baudgen, best_error;
186 	uint32_t baud_out, err;
187 
188 	best_bauddiv = 0;
189 	best_baudgen = 0;
190 	best_error = ~0;
191 
192 	/* Try all possible bauddiv values and pick best match. */
193 	for (bauddiv = 4; bauddiv <= 255; bauddiv++) {
194 		baudgen = (bas->rclk + (baudrate * (bauddiv + 1)) / 2) /
195 			(baudrate * (bauddiv + 1));
196 		if (baudgen < 1 || baudgen > 0xffff)
197 			continue;
198 
199 		baud_out = bas->rclk / (baudgen * (bauddiv + 1));
200 		err = baud_out > baudrate ?
201 			baud_out - baudrate : baudrate - baud_out;
202 
203 		if (err < best_error) {
204 			best_error = err;
205 			best_bauddiv = bauddiv;
206 			best_baudgen = baudgen;
207 		}
208 	}
209 
210 	if (best_bauddiv > 0) {
211 		WR4(bas, CDNC_UART_BAUDDIV_REG, best_bauddiv);
212 		WR4(bas, CDNC_UART_BAUDGEN_REG, best_baudgen);
213 		return (0);
214 	} else
215 		return (-1); /* out of range */
216 }
217 
218 static int
219 cdnc_uart_set_params(struct uart_bas *bas, int baudrate, int databits,
220 		      int stopbits, int parity)
221 {
222 	uint32_t mode_reg_value = 0;
223 
224 	switch (databits) {
225 	case 6:
226 		mode_reg_value |= CDNC_UART_MODE_REG_6BIT;
227 		break;
228 	case 7:
229 		mode_reg_value |= CDNC_UART_MODE_REG_7BIT;
230 		break;
231 	case 8:
232 	default:
233 		mode_reg_value |= CDNC_UART_MODE_REG_8BIT;
234 		break;
235 	}
236 
237 	if (stopbits == 2)
238 		mode_reg_value |= CDNC_UART_MODE_REG_STOP2;
239 
240 	switch (parity) {
241 	case UART_PARITY_MARK:
242 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_MARK;
243 		break;
244 	case UART_PARITY_SPACE:
245 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_SPACE;
246 		break;
247 	case UART_PARITY_ODD:
248 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_ODD;
249 		break;
250 	case UART_PARITY_EVEN:
251 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_EVEN;
252 		break;
253 	case UART_PARITY_NONE:
254 	default:
255 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_NONE;
256 		break;
257 	}
258 
259 	WR4(bas, CDNC_UART_MODE_REG, mode_reg_value);
260 
261 	if (baudrate > 0 && cdnc_uart_set_baud(bas, baudrate) < 0)
262 		return (EINVAL);
263 
264 	return(0);
265 }
266 
267 static void
268 cdnc_uart_hw_init(struct uart_bas *bas)
269 {
270 
271 	/* Reset RX and TX. */
272 	WR4(bas, CDNC_UART_CTRL_REG,
273 	    CDNC_UART_CTRL_REG_RXRST | CDNC_UART_CTRL_REG_TXRST);
274 
275 	/* Interrupts all off. */
276 	WR4(bas, CDNC_UART_IDIS_REG, CDNC_UART_INT_ALL);
277 	WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_ALL);
278 
279 	/* Clear delta bits. */
280 	WR4(bas, CDNC_UART_MODEM_STAT_REG,
281 	    CDNC_UART_MODEM_STAT_REG_DDCD | CDNC_UART_MODEM_STAT_REG_TERI |
282 	    CDNC_UART_MODEM_STAT_REG_DDSR | CDNC_UART_MODEM_STAT_REG_DCTS);
283 
284 	/* RX FIFO water level, stale timeout */
285 	WR4(bas, CDNC_UART_RX_WATER_REG, UART_FIFO_SIZE/2);
286 	WR4(bas, CDNC_UART_RX_TIMEO_REG, 10);
287 
288 	/* TX FIFO water level (not used.) */
289 	WR4(bas, CDNC_UART_TX_WATER_REG, UART_FIFO_SIZE/2);
290 
291 	/* Bring RX and TX online. */
292 	WR4(bas, CDNC_UART_CTRL_REG,
293 	    CDNC_UART_CTRL_REG_RX_EN | CDNC_UART_CTRL_REG_TX_EN |
294 	    CDNC_UART_CTRL_REG_TORST | CDNC_UART_CTRL_REG_STOPBRK);
295 
296 	/* Set DTR and RTS. */
297 	WR4(bas, CDNC_UART_MODEM_CTRL_REG, CDNC_UART_MODEM_CTRL_REG_DTR |
298 	    CDNC_UART_MODEM_CTRL_REG_RTS);
299 }
300 
301 /*
302  * Initialize this device for use as a console.
303  */
304 static void
305 cdnc_uart_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
306 	      int parity)
307 {
308 
309 	/* Initialize hardware. */
310 	cdnc_uart_hw_init(bas);
311 
312 	/* Set baudrate, parameters. */
313 	(void)cdnc_uart_set_params(bas, baudrate, databits, stopbits, parity);
314 }
315 
316 /*
317  * Free resources now that we're no longer the console.  This appears to
318  * be never called, and I'm unsure quite what to do if I am called.
319  */
320 static void
321 cdnc_uart_term(struct uart_bas *bas)
322 {
323 
324 	/* XXX */
325 }
326 
327 /*
328  * Put a character of console output (so we do it here polling rather than
329  * interrupt driven).
330  */
331 static void
332 cdnc_uart_putc(struct uart_bas *bas, int c)
333 {
334 
335 	/* Wait for room. */
336 	while ((RD4(bas,CDNC_UART_CHAN_STAT_REG) &
337 		CDNC_UART_CHAN_STAT_REG_TXFULL) != 0)
338 		;
339 
340 	WR4(bas, CDNC_UART_FIFO, c);
341 
342 	while ((RD4(bas,CDNC_UART_CHAN_STAT_REG) &
343 		CDNC_UART_CHAN_STAT_REG_TXEMPTY) == 0)
344 		;
345 }
346 
347 /*
348  * Check for a character available.
349  */
350 static int
351 cdnc_uart_rxready(struct uart_bas *bas)
352 {
353 
354 	return ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
355 		 CDNC_UART_CHAN_STAT_REG_RXEMPTY) == 0);
356 }
357 
358 /*
359  * Block waiting for a character.
360  */
361 static int
362 cdnc_uart_getc(struct uart_bas *bas, struct mtx *mtx)
363 {
364 	int c;
365 
366 	uart_lock(mtx);
367 
368 	while ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
369 		CDNC_UART_CHAN_STAT_REG_RXEMPTY) != 0) {
370 		uart_unlock(mtx);
371 		DELAY(4);
372 		uart_lock(mtx);
373 	}
374 
375 	c = RD4(bas, CDNC_UART_FIFO);
376 
377 	uart_unlock(mtx);
378 
379 	c &= 0xff;
380 	return (c);
381 }
382 
383 /*****************************************************************************/
384 /*
385  * High-level UART interface.
386  */
387 
388 static int cdnc_uart_bus_probe(struct uart_softc *sc);
389 static int cdnc_uart_bus_attach(struct uart_softc *sc);
390 static int cdnc_uart_bus_flush(struct uart_softc *, int);
391 static int cdnc_uart_bus_getsig(struct uart_softc *);
392 static int cdnc_uart_bus_ioctl(struct uart_softc *, int, intptr_t);
393 static int cdnc_uart_bus_ipend(struct uart_softc *);
394 static int cdnc_uart_bus_param(struct uart_softc *, int, int, int, int);
395 static int cdnc_uart_bus_receive(struct uart_softc *);
396 static int cdnc_uart_bus_setsig(struct uart_softc *, int);
397 static int cdnc_uart_bus_transmit(struct uart_softc *);
398 static void cdnc_uart_bus_grab(struct uart_softc *);
399 static void cdnc_uart_bus_ungrab(struct uart_softc *);
400 
401 static kobj_method_t cdnc_uart_bus_methods[] = {
402 	KOBJMETHOD(uart_probe,		cdnc_uart_bus_probe),
403 	KOBJMETHOD(uart_attach, 	cdnc_uart_bus_attach),
404 	KOBJMETHOD(uart_flush,		cdnc_uart_bus_flush),
405 	KOBJMETHOD(uart_getsig,		cdnc_uart_bus_getsig),
406 	KOBJMETHOD(uart_ioctl,		cdnc_uart_bus_ioctl),
407 	KOBJMETHOD(uart_ipend,		cdnc_uart_bus_ipend),
408 	KOBJMETHOD(uart_param,		cdnc_uart_bus_param),
409 	KOBJMETHOD(uart_receive,	cdnc_uart_bus_receive),
410 	KOBJMETHOD(uart_setsig,		cdnc_uart_bus_setsig),
411 	KOBJMETHOD(uart_transmit,	cdnc_uart_bus_transmit),
412 	KOBJMETHOD(uart_grab,		cdnc_uart_bus_grab),
413 	KOBJMETHOD(uart_ungrab,		cdnc_uart_bus_ungrab),
414 
415 	KOBJMETHOD_END
416 };
417 
418 int
419 cdnc_uart_bus_probe(struct uart_softc *sc)
420 {
421 
422 	sc->sc_txfifosz = UART_FIFO_SIZE;
423 	sc->sc_rxfifosz = UART_FIFO_SIZE;
424 	sc->sc_hwiflow = 0;
425 	sc->sc_hwoflow = 0;
426 
427 	device_set_desc(sc->sc_dev, "Cadence UART");
428 
429 	return (0);
430 }
431 
432 static int
433 cdnc_uart_bus_attach(struct uart_softc *sc)
434 {
435 	struct uart_bas *bas = &sc->sc_bas;
436 	struct uart_devinfo *di;
437 
438 	if (sc->sc_sysdev != NULL) {
439 		di = sc->sc_sysdev;
440 		(void)cdnc_uart_set_params(bas, di->baudrate, di->databits,
441 					   di->stopbits, di->parity);
442 	} else
443 		cdnc_uart_hw_init(bas);
444 
445 	(void)cdnc_uart_bus_getsig(sc);
446 
447 	/* Enable interrupts. */
448 	WR4(bas, CDNC_UART_IEN_REG,
449 	    CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
450 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
451 	    CDNC_UART_INT_DMSI);
452 
453 	return (0);
454 }
455 
456 static int
457 cdnc_uart_bus_transmit(struct uart_softc *sc)
458 {
459 	int i;
460 	struct uart_bas *bas = &sc->sc_bas;
461 
462 	uart_lock(sc->sc_hwmtx);
463 
464 	/* Clear sticky TXEMPTY status bit. */
465 	WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_TXEMPTY);
466 
467 	for (i = 0; i < sc->sc_txdatasz; i++)
468 		WR4(bas, CDNC_UART_FIFO, sc->sc_txbuf[i]);
469 
470 	/* Enable TX empty interrupt. */
471 	WR4(bas, CDNC_UART_IEN_REG, CDNC_UART_INT_TXEMPTY);
472 	sc->sc_txbusy = 1;
473 
474 	uart_unlock(sc->sc_hwmtx);
475 
476 	return (0);
477 }
478 
479 static int
480 cdnc_uart_bus_setsig(struct uart_softc *sc, int sig)
481 {
482 	struct uart_bas *bas = &sc->sc_bas;
483 	uint32_t new, old, modem_ctrl;
484 
485 	do {
486 		old = sc->sc_hwsig;
487 		new = old;
488 		if (sig & SER_DDTR) {
489 			SIGCHG(sig & SER_DTR, new, SER_DTR, SER_DDTR);
490 		}
491 		if (sig & SER_DRTS) {
492 			SIGCHG(sig & SER_RTS, new, SER_RTS, SER_DRTS);
493 		}
494 	} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
495 	uart_lock(sc->sc_hwmtx);
496 	modem_ctrl = RD4(bas, CDNC_UART_MODEM_CTRL_REG) &
497 		~(CDNC_UART_MODEM_CTRL_REG_DTR | CDNC_UART_MODEM_CTRL_REG_RTS);
498 	if ((new & SER_DTR) != 0)
499 		modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_DTR;
500 	if ((new & SER_RTS) != 0)
501 		modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_RTS;
502 	WR4(bas, CDNC_UART_MODEM_CTRL_REG, modem_ctrl);
503 
504 	uart_unlock(sc->sc_hwmtx);
505 	return (0);
506 }
507 
508 static int
509 cdnc_uart_bus_receive(struct uart_softc *sc)
510 {
511 	struct uart_bas *bas = &sc->sc_bas;
512 	uint32_t status;
513 	int c, c_status = 0;
514 
515 	uart_lock(sc->sc_hwmtx);
516 
517 	/* Check for parity or framing errors and clear the status bits. */
518 	status = RD4(bas, CDNC_UART_ISTAT_REG);
519 	if ((status & (CDNC_UART_INT_FRAMING | CDNC_UART_INT_PARITY)) != 0) {
520 		WR4(bas, CDNC_UART_ISTAT_REG,
521 		    status & (CDNC_UART_INT_FRAMING | CDNC_UART_INT_PARITY));
522 		if ((status & CDNC_UART_INT_PARITY) != 0)
523 			c_status |= UART_STAT_PARERR;
524 		if ((status & CDNC_UART_INT_FRAMING) != 0)
525 			c_status |= UART_STAT_FRAMERR;
526 	}
527 
528 	while ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
529 		CDNC_UART_CHAN_STAT_REG_RXEMPTY) == 0) {
530 		c = RD4(bas, CDNC_UART_FIFO) & 0xff;
531 #ifdef KDB
532 		/* Detect break and drop into debugger. */
533 		if (c == 0 && (c_status & UART_STAT_FRAMERR) != 0 &&
534 		    sc->sc_sysdev != NULL &&
535 		    sc->sc_sysdev->type == UART_DEV_CONSOLE) {
536 			kdb_break();
537 			WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_FRAMING);
538 		}
539 #endif
540 		uart_rx_put(sc, c | c_status);
541 	}
542 
543 	uart_unlock(sc->sc_hwmtx);
544 
545 	return (0);
546 }
547 
548 static int
549 cdnc_uart_bus_param(struct uart_softc *sc, int baudrate, int databits,
550 		   int stopbits, int parity)
551 {
552 
553 	return (cdnc_uart_set_params(&sc->sc_bas, baudrate,
554 				    databits, stopbits, parity));
555 }
556 
557 static int
558 cdnc_uart_bus_ipend(struct uart_softc *sc)
559 {
560 	int ipend = 0;
561 	struct uart_bas *bas = &sc->sc_bas;
562 	uint32_t istatus;
563 
564 	uart_lock(sc->sc_hwmtx);
565 
566 	istatus = RD4(bas, CDNC_UART_ISTAT_REG);
567 
568 	/* Clear interrupt bits. */
569 	WR4(bas, CDNC_UART_ISTAT_REG, istatus &
570 	    (CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
571 	     CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
572 	     CDNC_UART_INT_TXEMPTY | CDNC_UART_INT_DMSI));
573 
574 	/* Receive data. */
575 	if ((istatus & (CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT)) != 0)
576 		ipend |= SER_INT_RXREADY;
577 
578 	/* Transmit fifo empty. */
579 	if (sc->sc_txbusy && (istatus & CDNC_UART_INT_TXEMPTY) != 0) {
580 		/* disable txempty interrupt. */
581 		WR4(bas, CDNC_UART_IDIS_REG, CDNC_UART_INT_TXEMPTY);
582 		ipend |= SER_INT_TXIDLE;
583 	}
584 
585 	/* TX Overflow. */
586 	if ((istatus & CDNC_UART_INT_TXOVR) != 0)
587 		ipend |= SER_INT_OVERRUN;
588 
589 	/* RX Overflow. */
590 	if ((istatus & CDNC_UART_INT_RXOVR) != 0)
591 		ipend |= SER_INT_OVERRUN;
592 
593 	/* Modem signal change. */
594 	if ((istatus & CDNC_UART_INT_DMSI) != 0) {
595 		WR4(bas, CDNC_UART_MODEM_STAT_REG,
596 		    CDNC_UART_MODEM_STAT_REG_DDCD |
597 		    CDNC_UART_MODEM_STAT_REG_TERI |
598 		    CDNC_UART_MODEM_STAT_REG_DDSR |
599 		    CDNC_UART_MODEM_STAT_REG_DCTS);
600 		ipend |= SER_INT_SIGCHG;
601 	}
602 
603 	uart_unlock(sc->sc_hwmtx);
604 	return (ipend);
605 }
606 
607 static int
608 cdnc_uart_bus_flush(struct uart_softc *sc, int what)
609 {
610 
611 	return (0);
612 }
613 
614 static int
615 cdnc_uart_bus_getsig(struct uart_softc *sc)
616 {
617 	struct uart_bas *bas = &sc->sc_bas;
618 	uint32_t new, old, sig;
619 	uint8_t modem_status;
620 
621 	do {
622 		old = sc->sc_hwsig;
623 		sig = old;
624 		uart_lock(sc->sc_hwmtx);
625 		modem_status = RD4(bas, CDNC_UART_MODEM_STAT_REG);
626 		uart_unlock(sc->sc_hwmtx);
627 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_DSR,
628 		       sig, SER_DSR, SER_DDSR);
629 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_CTS,
630 		       sig, SER_CTS, SER_DCTS);
631 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_DCD,
632 		       sig, SER_DCD, SER_DDCD);
633 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_RI,
634 		       sig, SER_RI,  SER_DRI);
635 		new = sig & ~SER_MASK_DELTA;
636 	} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
637 	return (sig);
638 }
639 
640 static int
641 cdnc_uart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
642 {
643 	struct uart_bas *bas = &sc->sc_bas;
644 	uint32_t uart_ctrl, modem_ctrl;
645 	int error = 0;
646 
647 	uart_lock(sc->sc_hwmtx);
648 
649 	switch (request) {
650 	case UART_IOCTL_BREAK:
651 		uart_ctrl = RD4(bas, CDNC_UART_CTRL_REG);
652 		if (data) {
653 			uart_ctrl |= CDNC_UART_CTRL_REG_STARTBRK;
654 			uart_ctrl &= ~CDNC_UART_CTRL_REG_STOPBRK;
655 		} else {
656 			uart_ctrl |= CDNC_UART_CTRL_REG_STOPBRK;
657 			uart_ctrl &= ~CDNC_UART_CTRL_REG_STARTBRK;
658 		}
659 		WR4(bas, CDNC_UART_CTRL_REG, uart_ctrl);
660 		break;
661 	case UART_IOCTL_IFLOW:
662 		modem_ctrl = RD4(bas, CDNC_UART_MODEM_CTRL_REG);
663 		if (data)
664 			modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_RTS;
665 		else
666 			modem_ctrl &= ~CDNC_UART_MODEM_CTRL_REG_RTS;
667 		WR4(bas, CDNC_UART_MODEM_CTRL_REG, modem_ctrl);
668 		break;
669 	default:
670 		error = EINVAL;
671 		break;
672 	}
673 
674 	uart_unlock(sc->sc_hwmtx);
675 
676 	return (error);
677 }
678 
679 static void
680 cdnc_uart_bus_grab(struct uart_softc *sc)
681 {
682 
683 	/* Enable interrupts. */
684 	WR4(&sc->sc_bas, CDNC_UART_IEN_REG,
685 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
686 	    CDNC_UART_INT_DMSI);
687 }
688 
689 static void
690 cdnc_uart_bus_ungrab(struct uart_softc *sc)
691 {
692 
693 	/* Enable interrupts. */
694 	WR4(&sc->sc_bas, CDNC_UART_IEN_REG,
695 	    CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
696 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
697 	    CDNC_UART_INT_DMSI);
698 }
699 
700 static struct uart_class uart_cdnc_class = {
701 	"cdnc_uart",
702 	cdnc_uart_bus_methods,
703 	sizeof(struct uart_softc),
704 	.uc_ops = &cdnc_uart_ops,
705 	.uc_range = 8
706 };
707 
708 static struct ofw_compat_data compat_data[] = {
709 	{"cadence,uart",	(uintptr_t)&uart_cdnc_class},
710 	{"cdns,uart-r1p12",	(uintptr_t)&uart_cdnc_class},
711 	{"xlnx,xuartps",	(uintptr_t)&uart_cdnc_class},
712 	{NULL,			(uintptr_t)NULL},
713 };
714 UART_FDT_CLASS_AND_DEVICE(compat_data);
715