uart_dev_at91usart.c revision 178766
1/*-
2 * Copyright (c) 2005 M. Warner Losh
3 * Copyright (c) 2005 Olivier Houchard
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/arm/at91/uart_dev_at91usart.c 178766 2008-05-04 23:29:38Z peter $");
30
31#include "opt_comconsole.h"
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/bus.h>
36#include <sys/conf.h>
37#include <sys/cons.h>
38#include <sys/tty.h>
39#include <machine/bus.h>
40
41#include <dev/uart/uart.h>
42#include <dev/uart/uart_cpu.h>
43#include <dev/uart/uart_bus.h>
44#include <arm/at91/at91rm92reg.h>
45#include <arm/at91/at91_usartreg.h>
46#include <arm/at91/at91_pdcreg.h>
47
48#include "uart_if.h"
49
50#define DEFAULT_RCLK		AT91C_MASTER_CLOCK
51#define	USART_BUFFER_SIZE	128
52
53/*
54 * High-level UART interface.
55 */
56struct at91_usart_rx {
57	bus_addr_t	pa;
58	uint8_t		buffer[USART_BUFFER_SIZE];
59	bus_dmamap_t	map;
60};
61
62struct at91_usart_softc {
63	struct uart_softc base;
64	bus_dma_tag_t dmatag;		/* bus dma tag for mbufs */
65	bus_dmamap_t tx_map;
66	uint32_t flags;
67#define HAS_TIMEOUT	1
68	struct at91_usart_rx ping_pong[2];
69	struct at91_usart_rx *ping;
70	struct at91_usart_rx *pong;
71};
72
73#define	RD4(bas, reg)		\
74	bus_space_read_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg))
75#define	WR4(bas, reg, value)	\
76	bus_space_write_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg), value)
77
78#define	SIGCHG(c, i, s, d)				\
79	do {						\
80		if (c) {				\
81			i |= (i & s) ? s : s | d;	\
82		} else {				\
83			i = (i & s) ? (i & ~s) | d : i;	\
84		}					\
85	} while (0);
86
87#define BAUD2DIVISOR(b) \
88	((((DEFAULT_RCLK * 10) / ((b) * 16)) + 5) / 10)
89
90/*
91 * Low-level UART interface.
92 */
93static int at91_usart_probe(struct uart_bas *bas);
94static void at91_usart_init(struct uart_bas *bas, int, int, int, int);
95static void at91_usart_term(struct uart_bas *bas);
96static void at91_usart_putc(struct uart_bas *bas, int);
97static int at91_usart_rxready(struct uart_bas *bas);
98static int at91_usart_getc(struct uart_bas *bas, struct mtx *mtx);
99
100extern SLIST_HEAD(uart_devinfo_list, uart_devinfo) uart_sysdevs;
101
102static int
103at91_usart_param(struct uart_bas *bas, int baudrate, int databits,
104    int stopbits, int parity)
105{
106	uint32_t mr;
107
108	/*
109	 * Assume 3-write RS-232 configuration.
110	 * XXX Not sure how uart will present the other modes to us, so
111	 * XXX they are unimplemented.  maybe ioctl?
112	 */
113	mr = USART_MR_MODE_NORMAL;
114	mr |= USART_MR_USCLKS_MCK;	/* Assume MCK */
115
116	/*
117	 * Or in the databits requested
118	 */
119	if (databits < 9)
120		mr &= ~USART_MR_MODE9;
121	switch (databits) {
122	case 5:
123		mr |= USART_MR_CHRL_5BITS;
124		break;
125	case 6:
126		mr |= USART_MR_CHRL_6BITS;
127		break;
128	case 7:
129		mr |= USART_MR_CHRL_7BITS;
130		break;
131	case 8:
132		mr |= USART_MR_CHRL_8BITS;
133		break;
134	case 9:
135		mr |= USART_MR_CHRL_8BITS | USART_MR_MODE9;
136		break;
137	default:
138		return (EINVAL);
139	}
140
141	/*
142	 * Or in the parity
143	 */
144	switch (parity) {
145	case UART_PARITY_NONE:
146		mr |= USART_MR_PAR_NONE;
147		break;
148	case UART_PARITY_ODD:
149		mr |= USART_MR_PAR_ODD;
150		break;
151	case UART_PARITY_EVEN:
152		mr |= USART_MR_PAR_EVEN;
153		break;
154	case UART_PARITY_MARK:
155		mr |= USART_MR_PAR_MARK;
156		break;
157	case UART_PARITY_SPACE:
158		mr |= USART_MR_PAR_SPACE;
159		break;
160	default:
161		return (EINVAL);
162	}
163
164	/*
165	 * Or in the stop bits.  Note: The hardware supports 1.5 stop
166	 * bits in async mode, but there's no way to specify that
167	 * AFAICT.  Instead, rely on the convention documented at
168	 * http://www.lammertbies.nl/comm/info/RS-232_specs.html which
169	 * states that 1.5 stop bits are used for 5 bit bytes and
170	 * 2 stop bits only for longer bytes.
171	 */
172	if (stopbits == 1)
173		mr |= USART_MR_NBSTOP_1;
174	else if (databits > 5)
175		mr |= USART_MR_NBSTOP_2;
176	else
177		mr |= USART_MR_NBSTOP_1_5;
178
179	/*
180	 * We want normal plumbing mode too, none of this fancy
181	 * loopback or echo mode.
182	 */
183	mr |= USART_MR_CHMODE_NORMAL;
184
185	mr &= ~USART_MR_MSBF;	/* lsb first */
186	mr &= ~USART_MR_CKLO_SCK;	/* Don't drive SCK */
187
188	WR4(bas, USART_MR, mr);
189
190	/*
191	 * Set the baud rate
192	 */
193	WR4(bas, USART_BRGR, BAUD2DIVISOR(baudrate));
194
195	/* XXX Need to take possible synchronous mode into account */
196	return (0);
197}
198
199static struct uart_ops at91_usart_ops = {
200	.probe = at91_usart_probe,
201	.init = at91_usart_init,
202	.term = at91_usart_term,
203	.putc = at91_usart_putc,
204	.rxready = at91_usart_rxready,
205	.getc = at91_usart_getc,
206};
207
208static int
209at91_usart_probe(struct uart_bas *bas)
210{
211	/* We know that this is always here */
212	return (0);
213}
214
215/*
216 * Initialize this device for use as a console.
217 */
218static void
219at91_usart_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
220    int parity)
221{
222
223	at91_usart_param(bas, baudrate, databits, stopbits, parity);
224
225	/* Reset the rx and tx buffers and turn on rx and tx */
226	WR4(bas, USART_CR, USART_CR_RSTSTA | USART_CR_RSTRX | USART_CR_RSTTX);
227	WR4(bas, USART_CR, USART_CR_RXEN | USART_CR_TXEN);
228	WR4(bas, USART_IDR, 0xffffffff);
229}
230
231/*
232 * Free resources now that we're no longer the console.  This appears to
233 * be never called, and I'm unsure quite what to do if I am called.
234 */
235static void
236at91_usart_term(struct uart_bas *bas)
237{
238	/* XXX */
239}
240
241/*
242 * Put a character of console output (so we do it here polling rather than
243 * interrutp driven).
244 */
245static void
246at91_usart_putc(struct uart_bas *bas, int c)
247{
248
249    while (!(RD4(bas, USART_CSR) & USART_CSR_TXRDY))
250		continue;
251	WR4(bas, USART_THR, c);
252}
253
254/*
255 * Check for a character available.
256 */
257static int
258at91_usart_rxready(struct uart_bas *bas)
259{
260
261	return ((RD4(bas, USART_CSR) & USART_CSR_RXRDY) != 0 ? 1 : 0);
262}
263
264/*
265 * Block waiting for a character.
266 */
267static int
268at91_usart_getc(struct uart_bas *bas, struct mtx *mtx)
269{
270	int c;
271
272	while (!(RD4(bas, USART_CSR) & USART_CSR_RXRDY))
273		continue;
274	c = RD4(bas, USART_RHR);
275	c &= 0xff;
276	return (c);
277}
278
279static int at91_usart_bus_probe(struct uart_softc *sc);
280static int at91_usart_bus_attach(struct uart_softc *sc);
281static int at91_usart_bus_flush(struct uart_softc *, int);
282static int at91_usart_bus_getsig(struct uart_softc *);
283static int at91_usart_bus_ioctl(struct uart_softc *, int, intptr_t);
284static int at91_usart_bus_ipend(struct uart_softc *);
285static int at91_usart_bus_param(struct uart_softc *, int, int, int, int);
286static int at91_usart_bus_receive(struct uart_softc *);
287static int at91_usart_bus_setsig(struct uart_softc *, int);
288static int at91_usart_bus_transmit(struct uart_softc *);
289
290static kobj_method_t at91_usart_methods[] = {
291	KOBJMETHOD(uart_probe,		at91_usart_bus_probe),
292	KOBJMETHOD(uart_attach, 	at91_usart_bus_attach),
293	KOBJMETHOD(uart_flush,		at91_usart_bus_flush),
294	KOBJMETHOD(uart_getsig,		at91_usart_bus_getsig),
295	KOBJMETHOD(uart_ioctl,		at91_usart_bus_ioctl),
296	KOBJMETHOD(uart_ipend,		at91_usart_bus_ipend),
297	KOBJMETHOD(uart_param,		at91_usart_bus_param),
298	KOBJMETHOD(uart_receive,	at91_usart_bus_receive),
299	KOBJMETHOD(uart_setsig,		at91_usart_bus_setsig),
300	KOBJMETHOD(uart_transmit,	at91_usart_bus_transmit),
301
302	{ 0, 0 }
303};
304
305int
306at91_usart_bus_probe(struct uart_softc *sc)
307{
308	return (0);
309}
310
311#ifndef SKYEYE_WORKAROUNDS
312static void
313at91_getaddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
314{
315	if (error != 0)
316		return;
317	*(bus_addr_t *)arg = segs[0].ds_addr;
318}
319#endif
320
321static int
322at91_usart_bus_attach(struct uart_softc *sc)
323{
324#ifndef SKYEYE_WORKAROUNDS
325	int err;
326	int i;
327#endif
328	uint32_t cr;
329	struct at91_usart_softc *atsc;
330
331	atsc = (struct at91_usart_softc *)sc;
332
333	/*
334	 * See if we have a TIMEOUT bit.  We disable all interrupts as
335	 * a side effect.  Boot loaders may have enabled them.  Since
336	 * a TIMEOUT interrupt can't happen without other setup, the
337	 * apparent race here can't actually happen.
338	 */
339	WR4(&sc->sc_bas, USART_IDR, 0xffffffff);
340	WR4(&sc->sc_bas, USART_IER, USART_CSR_TIMEOUT);
341	if (RD4(&sc->sc_bas, USART_IMR) & USART_CSR_TIMEOUT)
342		atsc->flags |= HAS_TIMEOUT;
343	WR4(&sc->sc_bas, USART_IDR, 0xffffffff);
344
345	sc->sc_txfifosz = USART_BUFFER_SIZE;
346	sc->sc_rxfifosz = USART_BUFFER_SIZE;
347	sc->sc_hwiflow = 0;
348
349#ifndef SKYEYE_WORKAROUNDS
350	/*
351	 * Allocate DMA tags and maps
352	 */
353	err = bus_dma_tag_create(NULL, 1, 0, BUS_SPACE_MAXADDR_32BIT,
354	    BUS_SPACE_MAXADDR, NULL, NULL, USART_BUFFER_SIZE, 1,
355	    USART_BUFFER_SIZE, BUS_DMA_ALLOCNOW, NULL, NULL, &atsc->dmatag);
356	if (err != 0)
357		goto errout;
358	err = bus_dmamap_create(atsc->dmatag, 0, &atsc->tx_map);
359	if (err != 0)
360		goto errout;
361	if (atsc->flags & HAS_TIMEOUT) {
362		for (i = 0; i < 2; i++) {
363			err = bus_dmamap_create(atsc->dmatag, 0,
364			    &atsc->ping_pong[i].map);
365			if (err != 0)
366				goto errout;
367			err = bus_dmamap_load(atsc->dmatag,
368			    atsc->ping_pong[i].map,
369			    atsc->ping_pong[i].buffer, sc->sc_rxfifosz,
370			    at91_getaddr, &atsc->ping_pong[i].pa, 0);
371			if (err != 0)
372				goto errout;
373			bus_dmamap_sync(atsc->dmatag, atsc->ping_pong[i].map,
374			    BUS_DMASYNC_PREREAD);
375		}
376		atsc->ping = &atsc->ping_pong[0];
377		atsc->pong = &atsc->ping_pong[1];
378	}
379#endif
380
381	/*
382	 * Prime the pump with the RX buffer.  We use two 64 byte bounce
383	 * buffers here to avoid data overflow.
384	 */
385
386	/* Turn on rx and tx */
387	cr = USART_CR_RSTSTA | USART_CR_RSTRX | USART_CR_RSTTX;
388	WR4(&sc->sc_bas, USART_CR, cr);
389	WR4(&sc->sc_bas, USART_CR, USART_CR_RXEN | USART_CR_TXEN);
390
391	/*
392	 * Setup the PDC to receive data.  We use the ping-pong buffers
393	 * so that we can more easily bounce between the two and so that
394	 * we get an interrupt 1/2 way through the software 'fifo' we have
395	 * to avoid overruns.
396	 */
397	if (atsc->flags & HAS_TIMEOUT) {
398		WR4(&sc->sc_bas, PDC_RPR, atsc->ping->pa);
399		WR4(&sc->sc_bas, PDC_RCR, sc->sc_rxfifosz);
400		WR4(&sc->sc_bas, PDC_RNPR, atsc->pong->pa);
401		WR4(&sc->sc_bas, PDC_RNCR, sc->sc_rxfifosz);
402		WR4(&sc->sc_bas, PDC_PTCR, PDC_PTCR_RXTEN);
403
404		/* Set the receive timeout to be 1.5 character times. */
405		WR4(&sc->sc_bas, USART_RTOR, 12);
406		WR4(&sc->sc_bas, USART_CR, USART_CR_STTTO);
407		WR4(&sc->sc_bas, USART_IER, USART_CSR_TIMEOUT |
408		    USART_CSR_RXBUFF | USART_CSR_ENDRX);
409	} else {
410		WR4(&sc->sc_bas, USART_IER, USART_CSR_RXRDY);
411	}
412	WR4(&sc->sc_bas, USART_IER, USART_CSR_RXBRK);
413#ifndef SKYEYE_WORKAROUNDS
414errout:;
415	// XXX bad
416	return (err);
417#else
418	return (0);
419#endif
420}
421
422static int
423at91_usart_bus_transmit(struct uart_softc *sc)
424{
425#ifndef SKYEYE_WORKAROUNDS
426	bus_addr_t addr;
427#endif
428	struct at91_usart_softc *atsc;
429
430	atsc = (struct at91_usart_softc *)sc;
431#ifndef SKYEYE_WORKAROUNDS
432	if (bus_dmamap_load(atsc->dmatag, atsc->tx_map, sc->sc_txbuf,
433	    sc->sc_txdatasz, at91_getaddr, &addr, 0) != 0)
434		return (EAGAIN);
435	bus_dmamap_sync(atsc->dmatag, atsc->tx_map, BUS_DMASYNC_PREWRITE);
436#endif
437
438	uart_lock(sc->sc_hwmtx);
439	sc->sc_txbusy = 1;
440#ifndef SKYEYE_WORKAROUNDS
441	/*
442	 * Setup the PDC to transfer the data and interrupt us when it
443	 * is done.  We've already requested the interrupt.
444	 */
445	WR4(&sc->sc_bas, PDC_TPR, addr);
446	WR4(&sc->sc_bas, PDC_TCR, sc->sc_txdatasz);
447	WR4(&sc->sc_bas, PDC_PTCR, PDC_PTCR_TXTEN);
448	WR4(&sc->sc_bas, USART_IER, USART_CSR_ENDTX);
449	uart_unlock(sc->sc_hwmtx);
450#else
451	for (int i = 0; i < sc->sc_txdatasz; i++)
452		at91_usart_putc(&sc->sc_bas, sc->sc_txbuf[i]);
453	/*
454	 * XXX: Gross hack : Skyeye doesn't raise an interrupt once the
455	 * transfer is done, so simulate it.
456	 */
457	WR4(&sc->sc_bas, USART_IER, USART_CSR_TXRDY);
458#endif
459	return (0);
460}
461static int
462at91_usart_bus_setsig(struct uart_softc *sc, int sig)
463{
464	uint32_t new, old, cr;
465	struct uart_bas *bas;
466
467	do {
468		old = sc->sc_hwsig;
469		new = old;
470		if (sig & SER_DDTR)
471			SIGCHG(sig & SER_DTR, new, SER_DTR, SER_DDTR);
472		if (sig & SER_DRTS)
473			SIGCHG(sig & SER_RTS, new, SER_RTS, SER_DRTS);
474	} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
475	bas = &sc->sc_bas;
476	uart_lock(sc->sc_hwmtx);
477	cr = 0;
478	if (new & SER_DTR)
479		cr |= USART_CR_DTREN;
480	else
481		cr |= USART_CR_DTRDIS;
482	if (new & SER_RTS)
483		cr |= USART_CR_RTSEN;
484	else
485		cr |= USART_CR_RTSDIS;
486	WR4(bas, USART_CR, cr);
487	uart_unlock(sc->sc_hwmtx);
488	return (0);
489}
490static int
491at91_usart_bus_receive(struct uart_softc *sc)
492{
493
494	return (0);
495}
496static int
497at91_usart_bus_param(struct uart_softc *sc, int baudrate, int databits,
498    int stopbits, int parity)
499{
500
501	return (at91_usart_param(&sc->sc_bas, baudrate, databits, stopbits,
502	    parity));
503}
504
505static __inline void
506at91_rx_put(struct uart_softc *sc, int key)
507{
508#if defined(KDB) && defined(ALT_BREAK_TO_DEBUGGER)
509	int kdb_brk;
510
511	if (sc->sc_sysdev != NULL && sc->sc_sysdev->type == UART_DEV_CONSOLE) {
512		if ((kdb_brk = kdb_alt_break(key, &sc->sc_altbrk)) != 0) {
513		case KDB_REQ_DEBUGGER:
514			kdb_enter(KDB_WHY_BREAK, "Break sequence on console");
515			break;
516		case KDB_REQ_PANIC:
517			kdb_panic("Panic sequence on console");
518			break;
519		case KDB_REQ_REBOOT:
520			kdb_reboot();
521			break;
522		}
523	}
524#endif
525	uart_rx_put(sc, key);
526}
527
528static int
529at91_usart_bus_ipend(struct uart_softc *sc)
530{
531	int csr = RD4(&sc->sc_bas, USART_CSR);
532	int ipend = 0, i, len;
533	struct at91_usart_softc *atsc;
534	struct at91_usart_rx *p;
535
536	atsc = (struct at91_usart_softc *)sc;
537	if (csr & USART_CSR_ENDTX) {
538		bus_dmamap_sync(atsc->dmatag, atsc->tx_map,
539		    BUS_DMASYNC_POSTWRITE);
540		bus_dmamap_unload(atsc->dmatag, atsc->tx_map);
541	}
542	uart_lock(sc->sc_hwmtx);
543	if (csr & USART_CSR_TXRDY) {
544		if (sc->sc_txbusy)
545			ipend |= SER_INT_TXIDLE;
546		WR4(&sc->sc_bas, USART_IDR, USART_CSR_TXRDY);
547	}
548	if (csr & USART_CSR_ENDTX) {
549		if (sc->sc_txbusy)
550			ipend |= SER_INT_TXIDLE;
551		WR4(&sc->sc_bas, USART_IDR, USART_CSR_ENDTX);
552	}
553
554	/*
555	 * Due to the contraints of the DMA engine present in the
556	 * atmel chip, I can't just say I have a rx interrupt pending
557	 * and do all the work elsewhere.  I need to look at the CSR
558	 * bits right now and do things based on them to avoid races.
559	 */
560	if ((atsc->flags & HAS_TIMEOUT) && (csr & USART_CSR_RXBUFF)) {
561		// Have a buffer overflow.  Copy all data from both
562		// ping and pong.  Insert overflow character.  Reset
563		// ping and pong and re-enable the PDC to receive
564		// characters again.
565		bus_dmamap_sync(atsc->dmatag, atsc->ping->map,
566		    BUS_DMASYNC_POSTREAD);
567		bus_dmamap_sync(atsc->dmatag, atsc->pong->map,
568		    BUS_DMASYNC_POSTREAD);
569		for (i = 0; i < sc->sc_rxfifosz; i++)
570			at91_rx_put(sc, atsc->ping->buffer[i]);
571		for (i = 0; i < sc->sc_rxfifosz; i++)
572			at91_rx_put(sc, atsc->pong->buffer[i]);
573		uart_rx_put(sc, UART_STAT_OVERRUN);
574		csr &= ~(USART_CSR_ENDRX | USART_CSR_TIMEOUT);
575		WR4(&sc->sc_bas, PDC_RPR, atsc->ping->pa);
576		WR4(&sc->sc_bas, PDC_RCR, sc->sc_rxfifosz);
577		WR4(&sc->sc_bas, PDC_RNPR, atsc->pong->pa);
578		WR4(&sc->sc_bas, PDC_RNCR, sc->sc_rxfifosz);
579		WR4(&sc->sc_bas, PDC_PTCR, PDC_PTCR_RXTEN);
580		ipend |= SER_INT_RXREADY;
581	}
582	if ((atsc->flags & HAS_TIMEOUT) && (csr & USART_CSR_ENDRX)) {
583		// Shuffle data from 'ping' of ping pong buffer, but
584		// leave current 'pong' in place, as it has become the
585		// new 'ping'.  We need to copy data and setup the old
586		// 'ping' as the new 'pong' when we're done.
587		bus_dmamap_sync(atsc->dmatag, atsc->ping->map,
588		    BUS_DMASYNC_POSTREAD);
589		for (i = 0; i < sc->sc_rxfifosz; i++)
590			at91_rx_put(sc, atsc->ping->buffer[i]);
591		p = atsc->ping;
592		atsc->ping = atsc->pong;
593		atsc->pong = p;
594		WR4(&sc->sc_bas, PDC_RNPR, atsc->pong->pa);
595		WR4(&sc->sc_bas, PDC_RNCR, sc->sc_rxfifosz);
596		ipend |= SER_INT_RXREADY;
597	}
598	if ((atsc->flags & HAS_TIMEOUT) && (csr & USART_CSR_TIMEOUT)) {
599		// We have one partial buffer.  We need to stop the
600		// PDC, get the number of characters left and from
601		// that compute number of valid characters.  We then
602		// need to reset ping and pong and reenable the PDC.
603		// Not sure if there's a race here at fast baud rates
604		// we need to worry about.
605		WR4(&sc->sc_bas, PDC_PTCR, PDC_PTCR_RXTDIS);
606		bus_dmamap_sync(atsc->dmatag, atsc->ping->map,
607		    BUS_DMASYNC_POSTREAD);
608		len = sc->sc_rxfifosz - RD4(&sc->sc_bas, PDC_RCR);
609		for (i = 0; i < len; i++)
610			at91_rx_put(sc, atsc->ping->buffer[i]);
611		WR4(&sc->sc_bas, PDC_RPR, atsc->ping->pa);
612		WR4(&sc->sc_bas, PDC_RCR, sc->sc_rxfifosz);
613		WR4(&sc->sc_bas, USART_CR, USART_CR_STTTO);
614		WR4(&sc->sc_bas, PDC_PTCR, PDC_PTCR_RXTEN);
615		ipend |= SER_INT_RXREADY;
616	}
617	if (!(atsc->flags & HAS_TIMEOUT) && (csr & USART_CSR_RXRDY)) {
618		// We have another charater in a device that doesn't support
619		// timeouts, so we do it one character at a time.
620		at91_rx_put(sc, RD4(&sc->sc_bas, USART_RHR) & 0xff);
621		ipend |= SER_INT_RXREADY;
622	}
623
624	if (csr & USART_CSR_RXBRK) {
625		unsigned int cr = USART_CR_RSTSTA;
626
627		ipend |= SER_INT_BREAK;
628		WR4(&sc->sc_bas, USART_CR, cr);
629	}
630	uart_unlock(sc->sc_hwmtx);
631	return (ipend);
632}
633static int
634at91_usart_bus_flush(struct uart_softc *sc, int what)
635{
636	return (0);
637}
638
639static int
640at91_usart_bus_getsig(struct uart_softc *sc)
641{
642	uint32_t new, sig;
643	uint8_t csr;
644
645	uart_lock(sc->sc_hwmtx);
646	csr = RD4(&sc->sc_bas, USART_CSR);
647	sig = 0;
648	if (csr & USART_CSR_CTS)
649		sig |= SER_CTS;
650	if (csr & USART_CSR_DCD)
651		sig |= SER_DCD;
652	if (csr & USART_CSR_DSR)
653		sig |= SER_DSR;
654	if (csr & USART_CSR_RI)
655		sig |= SER_RI;
656	new = sig & ~SER_MASK_DELTA;
657	sc->sc_hwsig = new;
658	uart_unlock(sc->sc_hwmtx);
659	return (sig);
660}
661
662static int
663at91_usart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
664{
665	switch (request) {
666	case UART_IOCTL_BREAK:
667	case UART_IOCTL_IFLOW:
668	case UART_IOCTL_OFLOW:
669		break;
670	case UART_IOCTL_BAUD:
671		WR4(&sc->sc_bas, USART_BRGR, BAUD2DIVISOR(*(int *)data));
672		return (0);
673	}
674	return (EINVAL);
675}
676
677struct uart_class at91_usart_class = {
678	"at91_usart",
679	at91_usart_methods,
680	sizeof(struct at91_usart_softc),
681	.uc_ops = &at91_usart_ops,
682	.uc_range = 8,
683	.uc_rclk = DEFAULT_RCLK
684};
685