xref: /freebsd/sys/arm/xilinx/uart_dev_cdnc.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/bus.h>
42 #include <sys/conf.h>
43 #include <sys/cons.h>
44 #include <machine/bus.h>
45 
46 #include <dev/uart/uart.h>
47 #include <dev/uart/uart_cpu.h>
48 #include <dev/uart/uart_cpu_fdt.h>
49 #include <dev/uart/uart_bus.h>
50 
51 #include "uart_if.h"
52 
53 #define	UART_FIFO_SIZE	64
54 
55 #define	RD4(bas, reg)		\
56 	bus_space_read_4((bas)->bst, (bas)->bsh, uart_regofs((bas), (reg)))
57 #define	WR4(bas, reg, value)	\
58 	bus_space_write_4((bas)->bst, (bas)->bsh, uart_regofs((bas), (reg)), \
59 			  (value))
60 
61 /* Register definitions for Cadence UART Controller.
62  */
63 #define CDNC_UART_CTRL_REG	0x00		/* Control Register. */
64 #define CDNC_UART_CTRL_REG_STOPBRK	(1<<8)
65 #define CDNC_UART_CTRL_REG_STARTBRK	(1<<7)
66 #define CDNC_UART_CTRL_REG_TORST	(1<<6)
67 #define CDNC_UART_CTRL_REG_TX_DIS	(1<<5)
68 #define CDNC_UART_CTRL_REG_TX_EN	(1<<4)
69 #define CDNC_UART_CTRL_REG_RX_DIS	(1<<3)
70 #define CDNC_UART_CTRL_REG_RX_EN	(1<<2)
71 #define CDNC_UART_CTRL_REG_TXRST	(1<<1)
72 #define CDNC_UART_CTRL_REG_RXRST	(1<<0)
73 
74 #define CDNC_UART_MODE_REG	0x04		/* Mode Register. */
75 #define CDNC_UART_MODE_REG_CHMOD_R_LOOP	(3<<8)	/* [9:8] - channel mode */
76 #define CDNC_UART_MODE_REG_CHMOD_L_LOOP	(2<<8)
77 #define CDNC_UART_MODE_REG_CHMOD_AUTECHO (1<<8)
78 #define CDNC_UART_MODE_REG_STOP2	(2<<6)	/* [7:6] - stop bits */
79 #define CDNC_UART_MODE_REG_PAR_NONE	(4<<3)	/* [5:3] - parity type */
80 #define CDNC_UART_MODE_REG_PAR_MARK	(3<<3)
81 #define CDNC_UART_MODE_REG_PAR_SPACE	(2<<3)
82 #define CDNC_UART_MODE_REG_PAR_ODD	(1<<3)
83 #define CDNC_UART_MODE_REG_PAR_EVEN	(0<<3)
84 #define CDNC_UART_MODE_REG_6BIT		(3<<1)	/* [2:1] - character len */
85 #define CDNC_UART_MODE_REG_7BIT		(2<<1)
86 #define CDNC_UART_MODE_REG_8BIT		(0<<1)
87 #define CDNC_UART_MODE_REG_CLKSEL	(1<<0)
88 
89 #define CDNC_UART_IEN_REG	0x08		/* Interrupt registers. */
90 #define CDNC_UART_IDIS_REG	0x0C
91 #define CDNC_UART_IMASK_REG	0x10
92 #define CDNC_UART_ISTAT_REG	0x14
93 #define CDNC_UART_INT_TXOVR		(1<<12)
94 #define CDNC_UART_INT_TXNRLYFUL		(1<<11)	/* tx "nearly" full */
95 #define CDNC_UART_INT_TXTRIG		(1<<10)
96 #define CDNC_UART_INT_DMSI		(1<<9)	/* delta modem status */
97 #define CDNC_UART_INT_RXTMOUT		(1<<8)
98 #define CDNC_UART_INT_PARITY		(1<<7)
99 #define CDNC_UART_INT_FRAMING		(1<<6)
100 #define CDNC_UART_INT_RXOVR		(1<<5)
101 #define CDNC_UART_INT_TXFULL		(1<<4)
102 #define CDNC_UART_INT_TXEMPTY		(1<<3)
103 #define CDNC_UART_INT_RXFULL		(1<<2)
104 #define CDNC_UART_INT_RXEMPTY		(1<<1)
105 #define CDNC_UART_INT_RXTRIG		(1<<0)
106 #define CDNC_UART_INT_ALL		0x1FFF
107 
108 #define CDNC_UART_BAUDGEN_REG	0x18
109 #define CDNC_UART_RX_TIMEO_REG	0x1C
110 #define CDNC_UART_RX_WATER_REG	0x20
111 
112 #define CDNC_UART_MODEM_CTRL_REG 0x24
113 #define CDNC_UART_MODEM_CTRL_REG_FCM	(1<<5)	/* automatic flow control */
114 #define CDNC_UART_MODEM_CTRL_REG_RTS	(1<<1)
115 #define CDNC_UART_MODEM_CTRL_REG_DTR	(1<<0)
116 
117 #define CDNC_UART_MODEM_STAT_REG 0x28
118 #define CDNC_UART_MODEM_STAT_REG_FCMS	(1<<8)	/* flow control mode (rw) */
119 #define CDNC_UART_MODEM_STAT_REG_DCD	(1<<7)
120 #define CDNC_UART_MODEM_STAT_REG_RI	(1<<6)
121 #define CDNC_UART_MODEM_STAT_REG_DSR	(1<<5)
122 #define CDNC_UART_MODEM_STAT_REG_CTS	(1<<4)
123 #define CDNC_UART_MODEM_STAT_REG_DDCD	(1<<3)	/* change in DCD (w1tc) */
124 #define CDNC_UART_MODEM_STAT_REG_TERI	(1<<2)	/* trail edge ring (w1tc) */
125 #define CDNC_UART_MODEM_STAT_REG_DDSR	(1<<1)	/* change in DSR (w1tc) */
126 #define CDNC_UART_MODEM_STAT_REG_DCTS	(1<<0)	/* change in CTS (w1tc) */
127 
128 #define CDNC_UART_CHAN_STAT_REG	0x2C		/* Channel status register. */
129 #define CDNC_UART_CHAN_STAT_REG_TXNRLYFUL (1<<14) /* tx "nearly" full */
130 #define CDNC_UART_CHAN_STAT_REG_TXTRIG	(1<<13)
131 #define CDNC_UART_CHAN_STAT_REG_FDELT	(1<<12)
132 #define CDNC_UART_CHAN_STAT_REG_TXACTIVE (1<<11)
133 #define CDNC_UART_CHAN_STAT_REG_RXACTIVE (1<<10)
134 #define CDNC_UART_CHAN_STAT_REG_TXFULL	(1<<4)
135 #define CDNC_UART_CHAN_STAT_REG_TXEMPTY	(1<<3)
136 #define CDNC_UART_CHAN_STAT_REG_RXEMPTY	(1<<1)
137 #define CDNC_UART_CHAN_STAT_REG_RXTRIG	(1<<0)
138 
139 #define CDNC_UART_FIFO		0x30		/* Data FIFO (tx and rx) */
140 #define CDNC_UART_BAUDDIV_REG	0x34
141 #define CDNC_UART_FLOWDEL_REG	0x38
142 #define CDNC_UART_TX_WATER_REG	0x44
143 
144 /*
145  * Low-level UART interface.
146  */
147 static int cdnc_uart_probe(struct uart_bas *bas);
148 static void cdnc_uart_init(struct uart_bas *bas, int, int, int, int);
149 static void cdnc_uart_term(struct uart_bas *bas);
150 static void cdnc_uart_putc(struct uart_bas *bas, int);
151 static int cdnc_uart_rxready(struct uart_bas *bas);
152 static int cdnc_uart_getc(struct uart_bas *bas, struct mtx *mtx);
153 
154 extern SLIST_HEAD(uart_devinfo_list, uart_devinfo) uart_sysdevs;
155 
156 static struct uart_ops cdnc_uart_ops = {
157 	.probe = cdnc_uart_probe,
158 	.init = cdnc_uart_init,
159 	.term = cdnc_uart_term,
160 	.putc = cdnc_uart_putc,
161 	.rxready = cdnc_uart_rxready,
162 	.getc = cdnc_uart_getc,
163 };
164 
165 #define	SIGCHG(c, i, s, d)				\
166 	if (c) {					\
167 		i |= (i & s) ? s : s | d;		\
168 	} else {					\
169 		i = (i & s) ? (i & ~s) | d : i;		\
170 	}
171 
172 static int
173 cdnc_uart_probe(struct uart_bas *bas)
174 {
175 
176 	return (0);
177 }
178 
179 static int
180 cdnc_uart_set_baud(struct uart_bas *bas, int baudrate)
181 {
182 	uint32_t baudgen, bauddiv;
183 	uint32_t best_bauddiv, best_baudgen, best_error;
184 	uint32_t baud_out, err;
185 
186 	best_bauddiv = 0;
187 	best_baudgen = 0;
188 	best_error = ~0;
189 
190 	/* Try all possible bauddiv values and pick best match. */
191 	for (bauddiv = 4; bauddiv <= 255; bauddiv++) {
192 		baudgen = (bas->rclk + (baudrate * (bauddiv + 1)) / 2) /
193 			(baudrate * (bauddiv + 1));
194 		if (baudgen < 1 || baudgen > 0xffff)
195 			continue;
196 
197 		baud_out = bas->rclk / (baudgen * (bauddiv + 1));
198 		err = baud_out > baudrate ?
199 			baud_out - baudrate : baudrate - baud_out;
200 
201 		if (err < best_error) {
202 			best_error = err;
203 			best_bauddiv = bauddiv;
204 			best_baudgen = baudgen;
205 		}
206 	}
207 
208 	if (best_bauddiv > 0) {
209 		WR4(bas, CDNC_UART_BAUDDIV_REG, best_bauddiv);
210 		WR4(bas, CDNC_UART_BAUDGEN_REG, best_baudgen);
211 		return (0);
212 	} else
213 		return (-1); /* out of range */
214 }
215 
216 static int
217 cdnc_uart_set_params(struct uart_bas *bas, int baudrate, int databits,
218 		      int stopbits, int parity)
219 {
220 	uint32_t mode_reg_value = 0;
221 
222 	switch (databits) {
223 	case 6:
224 		mode_reg_value |= CDNC_UART_MODE_REG_6BIT;
225 		break;
226 	case 7:
227 		mode_reg_value |= CDNC_UART_MODE_REG_7BIT;
228 		break;
229 	case 8:
230 	default:
231 		mode_reg_value |= CDNC_UART_MODE_REG_8BIT;
232 		break;
233 	}
234 
235 	if (stopbits == 2)
236 		mode_reg_value |= CDNC_UART_MODE_REG_STOP2;
237 
238 	switch (parity) {
239 	case UART_PARITY_MARK:
240 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_MARK;
241 		break;
242 	case UART_PARITY_SPACE:
243 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_SPACE;
244 		break;
245 	case UART_PARITY_ODD:
246 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_ODD;
247 		break;
248 	case UART_PARITY_EVEN:
249 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_EVEN;
250 		break;
251 	case UART_PARITY_NONE:
252 	default:
253 		mode_reg_value |= CDNC_UART_MODE_REG_PAR_NONE;
254 		break;
255 	}
256 
257 	WR4(bas, CDNC_UART_MODE_REG, mode_reg_value);
258 
259 	if (baudrate > 0 && cdnc_uart_set_baud(bas, baudrate) < 0)
260 		return (EINVAL);
261 
262 	return(0);
263 }
264 
265 static void
266 cdnc_uart_hw_init(struct uart_bas *bas)
267 {
268 
269 	/* Reset RX and TX. */
270 	WR4(bas, CDNC_UART_CTRL_REG,
271 	    CDNC_UART_CTRL_REG_RXRST | CDNC_UART_CTRL_REG_TXRST);
272 
273 	/* Interrupts all off. */
274 	WR4(bas, CDNC_UART_IDIS_REG, CDNC_UART_INT_ALL);
275 	WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_ALL);
276 
277 	/* Clear delta bits. */
278 	WR4(bas, CDNC_UART_MODEM_STAT_REG,
279 	    CDNC_UART_MODEM_STAT_REG_DDCD | CDNC_UART_MODEM_STAT_REG_TERI |
280 	    CDNC_UART_MODEM_STAT_REG_DDSR | CDNC_UART_MODEM_STAT_REG_DCTS);
281 
282 	/* RX FIFO water level, stale timeout */
283 	WR4(bas, CDNC_UART_RX_WATER_REG, UART_FIFO_SIZE/2);
284 	WR4(bas, CDNC_UART_RX_TIMEO_REG, 10);
285 
286 	/* TX FIFO water level (not used.) */
287 	WR4(bas, CDNC_UART_TX_WATER_REG, UART_FIFO_SIZE/2);
288 
289 	/* Bring RX and TX online. */
290 	WR4(bas, CDNC_UART_CTRL_REG,
291 	    CDNC_UART_CTRL_REG_RX_EN | CDNC_UART_CTRL_REG_TX_EN |
292 	    CDNC_UART_CTRL_REG_TORST | CDNC_UART_CTRL_REG_STOPBRK);
293 
294 	/* Set DTR and RTS. */
295 	WR4(bas, CDNC_UART_MODEM_CTRL_REG, CDNC_UART_MODEM_CTRL_REG_DTR |
296 	    CDNC_UART_MODEM_CTRL_REG_RTS);
297 }
298 
299 /*
300  * Initialize this device for use as a console.
301  */
302 static void
303 cdnc_uart_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
304 	      int parity)
305 {
306 
307 	/* Initialize hardware. */
308 	cdnc_uart_hw_init(bas);
309 
310 	/* Set baudrate, parameters. */
311 	(void)cdnc_uart_set_params(bas, baudrate, databits, stopbits, parity);
312 }
313 
314 /*
315  * Free resources now that we're no longer the console.  This appears to
316  * be never called, and I'm unsure quite what to do if I am called.
317  */
318 static void
319 cdnc_uart_term(struct uart_bas *bas)
320 {
321 
322 	/* XXX */
323 }
324 
325 /*
326  * Put a character of console output (so we do it here polling rather than
327  * interrupt driven).
328  */
329 static void
330 cdnc_uart_putc(struct uart_bas *bas, int c)
331 {
332 
333 	/* Wait for room. */
334 	while ((RD4(bas,CDNC_UART_CHAN_STAT_REG) &
335 		CDNC_UART_CHAN_STAT_REG_TXFULL) != 0)
336 		;
337 
338 	WR4(bas, CDNC_UART_FIFO, c);
339 
340 	while ((RD4(bas,CDNC_UART_CHAN_STAT_REG) &
341 		CDNC_UART_CHAN_STAT_REG_TXEMPTY) == 0)
342 		;
343 }
344 
345 /*
346  * Check for a character available.
347  */
348 static int
349 cdnc_uart_rxready(struct uart_bas *bas)
350 {
351 
352 	return ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
353 		 CDNC_UART_CHAN_STAT_REG_RXEMPTY) == 0);
354 }
355 
356 /*
357  * Block waiting for a character.
358  */
359 static int
360 cdnc_uart_getc(struct uart_bas *bas, struct mtx *mtx)
361 {
362 	int c;
363 
364 	uart_lock(mtx);
365 
366 	while ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
367 		CDNC_UART_CHAN_STAT_REG_RXEMPTY) != 0) {
368 		uart_unlock(mtx);
369 		DELAY(4);
370 		uart_lock(mtx);
371 	}
372 
373 	c = RD4(bas, CDNC_UART_FIFO);
374 
375 	uart_unlock(mtx);
376 
377 	c &= 0xff;
378 	return (c);
379 }
380 
381 /*****************************************************************************/
382 /*
383  * High-level UART interface.
384  */
385 
386 static int cdnc_uart_bus_probe(struct uart_softc *sc);
387 static int cdnc_uart_bus_attach(struct uart_softc *sc);
388 static int cdnc_uart_bus_flush(struct uart_softc *, int);
389 static int cdnc_uart_bus_getsig(struct uart_softc *);
390 static int cdnc_uart_bus_ioctl(struct uart_softc *, int, intptr_t);
391 static int cdnc_uart_bus_ipend(struct uart_softc *);
392 static int cdnc_uart_bus_param(struct uart_softc *, int, int, int, int);
393 static int cdnc_uart_bus_receive(struct uart_softc *);
394 static int cdnc_uart_bus_setsig(struct uart_softc *, int);
395 static int cdnc_uart_bus_transmit(struct uart_softc *);
396 static void cdnc_uart_bus_grab(struct uart_softc *);
397 static void cdnc_uart_bus_ungrab(struct uart_softc *);
398 
399 static kobj_method_t cdnc_uart_bus_methods[] = {
400 	KOBJMETHOD(uart_probe,		cdnc_uart_bus_probe),
401 	KOBJMETHOD(uart_attach, 	cdnc_uart_bus_attach),
402 	KOBJMETHOD(uart_flush,		cdnc_uart_bus_flush),
403 	KOBJMETHOD(uart_getsig,		cdnc_uart_bus_getsig),
404 	KOBJMETHOD(uart_ioctl,		cdnc_uart_bus_ioctl),
405 	KOBJMETHOD(uart_ipend,		cdnc_uart_bus_ipend),
406 	KOBJMETHOD(uart_param,		cdnc_uart_bus_param),
407 	KOBJMETHOD(uart_receive,	cdnc_uart_bus_receive),
408 	KOBJMETHOD(uart_setsig,		cdnc_uart_bus_setsig),
409 	KOBJMETHOD(uart_transmit,	cdnc_uart_bus_transmit),
410 	KOBJMETHOD(uart_grab,		cdnc_uart_bus_grab),
411 	KOBJMETHOD(uart_ungrab,		cdnc_uart_bus_ungrab),
412 
413 	KOBJMETHOD_END
414 };
415 
416 int
417 cdnc_uart_bus_probe(struct uart_softc *sc)
418 {
419 
420 	sc->sc_txfifosz = UART_FIFO_SIZE;
421 	sc->sc_rxfifosz = UART_FIFO_SIZE;
422 	sc->sc_hwiflow = 0;
423 	sc->sc_hwoflow = 0;
424 
425 	device_set_desc(sc->sc_dev, "Cadence UART");
426 
427 	return (0);
428 }
429 
430 static int
431 cdnc_uart_bus_attach(struct uart_softc *sc)
432 {
433 	struct uart_bas *bas = &sc->sc_bas;
434 	struct uart_devinfo *di;
435 
436 	if (sc->sc_sysdev != NULL) {
437 		di = sc->sc_sysdev;
438 		(void)cdnc_uart_set_params(bas, di->baudrate, di->databits,
439 					   di->stopbits, di->parity);
440 	} else
441 		cdnc_uart_hw_init(bas);
442 
443 	(void)cdnc_uart_bus_getsig(sc);
444 
445 	/* Enable interrupts. */
446 	WR4(bas, CDNC_UART_IEN_REG,
447 	    CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
448 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
449 	    CDNC_UART_INT_DMSI);
450 
451 	return (0);
452 }
453 
454 static int
455 cdnc_uart_bus_transmit(struct uart_softc *sc)
456 {
457 	int i;
458 	struct uart_bas *bas = &sc->sc_bas;
459 
460 	uart_lock(sc->sc_hwmtx);
461 
462 	/* Clear sticky TXEMPTY status bit. */
463 	WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_TXEMPTY);
464 
465 	for (i = 0; i < sc->sc_txdatasz; i++)
466 		WR4(bas, CDNC_UART_FIFO, sc->sc_txbuf[i]);
467 
468 	/* Enable TX empty interrupt. */
469 	WR4(bas, CDNC_UART_IEN_REG, CDNC_UART_INT_TXEMPTY);
470 	sc->sc_txbusy = 1;
471 
472 	uart_unlock(sc->sc_hwmtx);
473 
474 	return (0);
475 }
476 
477 static int
478 cdnc_uart_bus_setsig(struct uart_softc *sc, int sig)
479 {
480 	struct uart_bas *bas = &sc->sc_bas;
481 	uint32_t new, old, modem_ctrl;
482 
483 	do {
484 		old = sc->sc_hwsig;
485 		new = old;
486 		if (sig & SER_DDTR) {
487 			SIGCHG(sig & SER_DTR, new, SER_DTR, SER_DDTR);
488 		}
489 		if (sig & SER_DRTS) {
490 			SIGCHG(sig & SER_RTS, new, SER_RTS, SER_DRTS);
491 		}
492 	} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
493 	uart_lock(sc->sc_hwmtx);
494 	modem_ctrl = RD4(bas, CDNC_UART_MODEM_CTRL_REG) &
495 		~(CDNC_UART_MODEM_CTRL_REG_DTR | CDNC_UART_MODEM_CTRL_REG_RTS);
496 	if ((new & SER_DTR) != 0)
497 		modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_DTR;
498 	if ((new & SER_RTS) != 0)
499 		modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_RTS;
500 	WR4(bas, CDNC_UART_MODEM_CTRL_REG, modem_ctrl);
501 
502 	uart_unlock(sc->sc_hwmtx);
503 	return (0);
504 }
505 
506 static int
507 cdnc_uart_bus_receive(struct uart_softc *sc)
508 {
509 	struct uart_bas *bas = &sc->sc_bas;
510 	uint32_t status;
511 	int c, c_status = 0;
512 
513 	uart_lock(sc->sc_hwmtx);
514 
515 	/* Check for parity or framing errors and clear the status bits. */
516 	status = RD4(bas, CDNC_UART_ISTAT_REG);
517 	if ((status & (CDNC_UART_INT_FRAMING | CDNC_UART_INT_PARITY)) != 0) {
518 		WR4(bas, CDNC_UART_ISTAT_REG,
519 		    status & (CDNC_UART_INT_FRAMING | CDNC_UART_INT_PARITY));
520 		if ((status & CDNC_UART_INT_PARITY) != 0)
521 			c_status |= UART_STAT_PARERR;
522 		if ((status & CDNC_UART_INT_FRAMING) != 0)
523 			c_status |= UART_STAT_FRAMERR;
524 	}
525 
526 	while ((RD4(bas, CDNC_UART_CHAN_STAT_REG) &
527 		CDNC_UART_CHAN_STAT_REG_RXEMPTY) == 0) {
528 		c = RD4(bas, CDNC_UART_FIFO) & 0xff;
529 #ifdef KDB
530 		/* Detect break and drop into debugger. */
531 		if (c == 0 && (c_status & UART_STAT_FRAMERR) != 0 &&
532 		    sc->sc_sysdev != NULL &&
533 		    sc->sc_sysdev->type == UART_DEV_CONSOLE) {
534 			kdb_break();
535 			WR4(bas, CDNC_UART_ISTAT_REG, CDNC_UART_INT_FRAMING);
536 		}
537 #endif
538 		uart_rx_put(sc, c | c_status);
539 	}
540 
541 	uart_unlock(sc->sc_hwmtx);
542 
543 	return (0);
544 }
545 
546 static int
547 cdnc_uart_bus_param(struct uart_softc *sc, int baudrate, int databits,
548 		   int stopbits, int parity)
549 {
550 
551 	return (cdnc_uart_set_params(&sc->sc_bas, baudrate,
552 				    databits, stopbits, parity));
553 }
554 
555 static int
556 cdnc_uart_bus_ipend(struct uart_softc *sc)
557 {
558 	int ipend = 0;
559 	struct uart_bas *bas = &sc->sc_bas;
560 	uint32_t istatus;
561 
562 	uart_lock(sc->sc_hwmtx);
563 
564 	istatus = RD4(bas, CDNC_UART_ISTAT_REG);
565 
566 	/* Clear interrupt bits. */
567 	WR4(bas, CDNC_UART_ISTAT_REG, istatus &
568 	    (CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
569 	     CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
570 	     CDNC_UART_INT_TXEMPTY | CDNC_UART_INT_DMSI));
571 
572 	/* Receive data. */
573 	if ((istatus & (CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT)) != 0)
574 		ipend |= SER_INT_RXREADY;
575 
576 	/* Transmit fifo empty. */
577 	if (sc->sc_txbusy && (istatus & CDNC_UART_INT_TXEMPTY) != 0) {
578 		/* disable txempty interrupt. */
579 		WR4(bas, CDNC_UART_IDIS_REG, CDNC_UART_INT_TXEMPTY);
580 		ipend |= SER_INT_TXIDLE;
581 	}
582 
583 	/* TX Overflow. */
584 	if ((istatus & CDNC_UART_INT_TXOVR) != 0)
585 		ipend |= SER_INT_OVERRUN;
586 
587 	/* RX Overflow. */
588 	if ((istatus & CDNC_UART_INT_RXOVR) != 0)
589 		ipend |= SER_INT_OVERRUN;
590 
591 	/* Modem signal change. */
592 	if ((istatus & CDNC_UART_INT_DMSI) != 0) {
593 		WR4(bas, CDNC_UART_MODEM_STAT_REG,
594 		    CDNC_UART_MODEM_STAT_REG_DDCD |
595 		    CDNC_UART_MODEM_STAT_REG_TERI |
596 		    CDNC_UART_MODEM_STAT_REG_DDSR |
597 		    CDNC_UART_MODEM_STAT_REG_DCTS);
598 		ipend |= SER_INT_SIGCHG;
599 	}
600 
601 	uart_unlock(sc->sc_hwmtx);
602 	return (ipend);
603 }
604 
605 static int
606 cdnc_uart_bus_flush(struct uart_softc *sc, int what)
607 {
608 
609 	return (0);
610 }
611 
612 static int
613 cdnc_uart_bus_getsig(struct uart_softc *sc)
614 {
615 	struct uart_bas *bas = &sc->sc_bas;
616 	uint32_t new, old, sig;
617 	uint8_t modem_status;
618 
619 	do {
620 		old = sc->sc_hwsig;
621 		sig = old;
622 		uart_lock(sc->sc_hwmtx);
623 		modem_status = RD4(bas, CDNC_UART_MODEM_STAT_REG);
624 		uart_unlock(sc->sc_hwmtx);
625 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_DSR,
626 		       sig, SER_DSR, SER_DDSR);
627 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_CTS,
628 		       sig, SER_CTS, SER_DCTS);
629 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_DCD,
630 		       sig, SER_DCD, SER_DDCD);
631 		SIGCHG(modem_status & CDNC_UART_MODEM_STAT_REG_RI,
632 		       sig, SER_RI,  SER_DRI);
633 		new = sig & ~SER_MASK_DELTA;
634 	} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
635 	return (sig);
636 }
637 
638 static int
639 cdnc_uart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
640 {
641 	struct uart_bas *bas = &sc->sc_bas;
642 	uint32_t uart_ctrl, modem_ctrl;
643 	int error = 0;
644 
645 	uart_lock(sc->sc_hwmtx);
646 
647 	switch (request) {
648 	case UART_IOCTL_BREAK:
649 		uart_ctrl = RD4(bas, CDNC_UART_CTRL_REG);
650 		if (data) {
651 			uart_ctrl |= CDNC_UART_CTRL_REG_STARTBRK;
652 			uart_ctrl &= ~CDNC_UART_CTRL_REG_STOPBRK;
653 		} else {
654 			uart_ctrl |= CDNC_UART_CTRL_REG_STOPBRK;
655 			uart_ctrl &= ~CDNC_UART_CTRL_REG_STARTBRK;
656 		}
657 		WR4(bas, CDNC_UART_CTRL_REG, uart_ctrl);
658 		break;
659 	case UART_IOCTL_IFLOW:
660 		modem_ctrl = RD4(bas, CDNC_UART_MODEM_CTRL_REG);
661 		if (data)
662 			modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_RTS;
663 		else
664 			modem_ctrl &= ~CDNC_UART_MODEM_CTRL_REG_RTS;
665 		WR4(bas, CDNC_UART_MODEM_CTRL_REG, modem_ctrl);
666 		break;
667 	default:
668 		error = EINVAL;
669 		break;
670 	}
671 
672 	uart_unlock(sc->sc_hwmtx);
673 
674 	return (error);
675 }
676 
677 static void
678 cdnc_uart_bus_grab(struct uart_softc *sc)
679 {
680 
681 	/* Enable interrupts. */
682 	WR4(&sc->sc_bas, CDNC_UART_IEN_REG,
683 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
684 	    CDNC_UART_INT_DMSI);
685 }
686 
687 static void
688 cdnc_uart_bus_ungrab(struct uart_softc *sc)
689 {
690 
691 	/* Enable interrupts. */
692 	WR4(&sc->sc_bas, CDNC_UART_IEN_REG,
693 	    CDNC_UART_INT_RXTRIG | CDNC_UART_INT_RXTMOUT |
694 	    CDNC_UART_INT_TXOVR | CDNC_UART_INT_RXOVR |
695 	    CDNC_UART_INT_DMSI);
696 }
697 
698 static struct uart_class uart_cdnc_class = {
699 	"cdnc_uart",
700 	cdnc_uart_bus_methods,
701 	sizeof(struct uart_softc),
702 	.uc_ops = &cdnc_uart_ops,
703 	.uc_range = 8
704 };
705 
706 static struct ofw_compat_data compat_data[] = {
707 	{"cadence,uart",	(uintptr_t)&uart_cdnc_class},
708 	{"cdns,uart-r1p12",	(uintptr_t)&uart_cdnc_class},
709 	{"xlnx,xuartps",	(uintptr_t)&uart_cdnc_class},
710 	{NULL,			(uintptr_t)NULL},
711 };
712 UART_FDT_CLASS_AND_DEVICE(compat_data);
713