1 /*-
2 * Copyright (c) 2013 Adrian Chadd <adrian@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/10.0/sys/mips/atheros/uart_dev_ar933x.c 249120 2013-04-05 00:26:06Z adrian $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/conf.h>
34 #include <machine/bus.h>
35
36 #include <dev/uart/uart.h>
37 #include <dev/uart/uart_cpu.h>
38 #include <dev/uart/uart_bus.h>
39
40 #include <mips/atheros/ar933x_uart.h>
41
42 #include "uart_if.h"
43
44 /*
45 * Default system clock is 25MHz; see ar933x_chip.c for how
46 * the startup process determines whether it's 25MHz or 40MHz.
47 */
48 #define DEFAULT_RCLK (25 * 1000 * 1000)
49
50 #define ar933x_getreg(bas, reg) \
51 bus_space_read_4((bas)->bst, (bas)->bsh, reg)
52 #define ar933x_setreg(bas, reg, value) \
53 bus_space_write_4((bas)->bst, (bas)->bsh, reg, value)
54
55
56
57 static int
58 ar933x_drain(struct uart_bas *bas, int what)
59 {
60 int limit;
61
62 if (what & UART_DRAIN_TRANSMITTER) {
63 limit = 10*1024;
64
65 /* Loop over until the TX FIFO shows entirely clear */
66 while (--limit) {
67 if ((ar933x_getreg(bas, AR933X_UART_CS_REG)
68 & AR933X_UART_CS_TX_BUSY) == 0)
69 break;
70 }
71 if (limit == 0) {
72 return (EIO);
73 }
74 }
75
76 if (what & UART_DRAIN_RECEIVER) {
77 limit=10*4096;
78 while (--limit) {
79
80 /* XXX duplicated from ar933x_getc() */
81 /* XXX TODO: refactor! */
82
83 /* If there's nothing to read, stop! */
84 if ((ar933x_getreg(bas, AR933X_UART_DATA_REG) &
85 AR933X_UART_DATA_RX_CSR) == 0) {
86 break;
87 }
88
89 /* Read the top of the RX FIFO */
90 (void) ar933x_getreg(bas, AR933X_UART_DATA_REG);
91
92 /* Remove that entry from said RX FIFO */
93 ar933x_setreg(bas, AR933X_UART_DATA_REG,
94 AR933X_UART_DATA_RX_CSR);
95
96 uart_barrier(bas);
97 DELAY(2);
98 }
99 if (limit == 0) {
100 return (EIO);
101 }
102 }
103 return (0);
104 }
105
106 /*
107 * Calculate the baud from the given chip configuration parameters.
108 */
109 static unsigned long
110 ar933x_uart_get_baud(unsigned int clk, unsigned int scale,
111 unsigned int step)
112 {
113 uint64_t t;
114 uint32_t div;
115
116 div = (2 << 16) * (scale + 1);
117 t = clk;
118 t *= step;
119 t += (div / 2);
120 t = t / div;
121
122 return (t);
123 }
124
125 /*
126 * Calculate the scale/step with the lowest possible deviation from
127 * the target baudrate.
128 */
129 static void
130 ar933x_uart_get_scale_step(struct uart_bas *bas, unsigned int baud,
131 unsigned int *scale, unsigned int *step)
132 {
133 unsigned int tscale;
134 uint32_t clk;
135 long min_diff;
136
137 clk = bas->rclk;
138 *scale = 0;
139 *step = 0;
140
141 min_diff = baud;
142 for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
143 uint64_t tstep;
144 int diff;
145
146 tstep = baud * (tscale + 1);
147 tstep *= (2 << 16);
148 tstep = tstep / clk;
149
150 if (tstep > AR933X_UART_MAX_STEP)
151 break;
152
153 diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
154 if (diff < min_diff) {
155 min_diff = diff;
156 *scale = tscale;
157 *step = tstep;
158 }
159 }
160 }
161
162 static int
163 ar933x_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
164 int parity)
165 {
166 /* UART always 8 bits */
167
168 /* UART always 1 stop bit */
169
170 /* UART parity is controllable by bits 0:1, ignore for now */
171
172 /* Set baudrate if required. */
173 if (baudrate > 0) {
174 uint32_t clock_scale, clock_step;
175
176 /* Find the best fit for the given baud rate */
177 ar933x_uart_get_scale_step(bas, baudrate, &clock_scale,
178 &clock_step);
179
180 /*
181 * Program the clock register in its entirety - no need
182 * for Read-Modify-Write.
183 */
184 ar933x_setreg(bas, AR933X_UART_CLOCK_REG,
185 ((clock_scale & AR933X_UART_CLOCK_SCALE_M)
186 << AR933X_UART_CLOCK_SCALE_S) |
187 (clock_step & AR933X_UART_CLOCK_STEP_M));
188 }
189
190 uart_barrier(bas);
191 return (0);
192 }
193
194
195 /*
196 * Low-level UART interface.
197 */
198 static int ar933x_probe(struct uart_bas *bas);
199 static void ar933x_init(struct uart_bas *bas, int, int, int, int);
200 static void ar933x_term(struct uart_bas *bas);
201 static void ar933x_putc(struct uart_bas *bas, int);
202 static int ar933x_rxready(struct uart_bas *bas);
203 static int ar933x_getc(struct uart_bas *bas, struct mtx *);
204
205 static struct uart_ops uart_ar933x_ops = {
206 .probe = ar933x_probe,
207 .init = ar933x_init,
208 .term = ar933x_term,
209 .putc = ar933x_putc,
210 .rxready = ar933x_rxready,
211 .getc = ar933x_getc,
212 };
213
214 static int
215 ar933x_probe(struct uart_bas *bas)
216 {
217
218 /* We always know this will be here */
219 return (0);
220 }
221
222 static void
223 ar933x_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
224 int parity)
225 {
226 uint32_t reg;
227
228 /* Setup default parameters */
229 ar933x_param(bas, baudrate, databits, stopbits, parity);
230
231 /* XXX Force enable UART in case it was disabled */
232
233 /* Disable all interrupts */
234 ar933x_setreg(bas, AR933X_UART_INT_EN_REG, 0x00000000);
235
236 /* Disable the host interrupt */
237 reg = ar933x_getreg(bas, AR933X_UART_CS_REG);
238 reg &= ~AR933X_UART_CS_HOST_INT_EN;
239 ar933x_setreg(bas, AR933X_UART_CS_REG, reg);
240
241 uart_barrier(bas);
242
243 /* XXX Set RTS/DTR? */
244 }
245
246 /*
247 * Detach from console.
248 */
249 static void
250 ar933x_term(struct uart_bas *bas)
251 {
252
253 /* XXX TODO */
254 }
255
256 static void
257 ar933x_putc(struct uart_bas *bas, int c)
258 {
259 int limit;
260
261 limit = 250000;
262
263 /* Wait for space in the TX FIFO */
264 while ( ((ar933x_getreg(bas, AR933X_UART_DATA_REG) &
265 AR933X_UART_DATA_TX_CSR) == 0) && --limit)
266 DELAY(4);
267
268 /* Write the actual byte */
269 ar933x_setreg(bas, AR933X_UART_DATA_REG,
270 (c & 0xff) | AR933X_UART_DATA_TX_CSR);
271 }
272
273 static int
274 ar933x_rxready(struct uart_bas *bas)
275 {
276
277 /* Wait for a character to come ready */
278 return (!!(ar933x_getreg(bas, AR933X_UART_DATA_REG)
279 & AR933X_UART_DATA_RX_CSR));
280 }
281
282 static int
283 ar933x_getc(struct uart_bas *bas, struct mtx *hwmtx)
284 {
285 int c;
286
287 uart_lock(hwmtx);
288
289 /* Wait for a character to come ready */
290 while ((ar933x_getreg(bas, AR933X_UART_DATA_REG) &
291 AR933X_UART_DATA_RX_CSR) == 0) {
292 uart_unlock(hwmtx);
293 DELAY(4);
294 uart_lock(hwmtx);
295 }
296
297 /* Read the top of the RX FIFO */
298 c = ar933x_getreg(bas, AR933X_UART_DATA_REG) & 0xff;
299
300 /* Remove that entry from said RX FIFO */
301 ar933x_setreg(bas, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR);
302
303 uart_unlock(hwmtx);
304
305 return (c);
306 }
307
308 /*
309 * High-level UART interface.
310 */
311 struct ar933x_softc {
312 struct uart_softc base;
313
314 uint32_t u_ier;
315 };
316
317 static int ar933x_bus_attach(struct uart_softc *);
318 static int ar933x_bus_detach(struct uart_softc *);
319 static int ar933x_bus_flush(struct uart_softc *, int);
320 static int ar933x_bus_getsig(struct uart_softc *);
321 static int ar933x_bus_ioctl(struct uart_softc *, int, intptr_t);
322 static int ar933x_bus_ipend(struct uart_softc *);
323 static int ar933x_bus_param(struct uart_softc *, int, int, int, int);
324 static int ar933x_bus_probe(struct uart_softc *);
325 static int ar933x_bus_receive(struct uart_softc *);
326 static int ar933x_bus_setsig(struct uart_softc *, int);
327 static int ar933x_bus_transmit(struct uart_softc *);
328
329 static kobj_method_t ar933x_methods[] = {
330 KOBJMETHOD(uart_attach, ar933x_bus_attach),
331 KOBJMETHOD(uart_detach, ar933x_bus_detach),
332 KOBJMETHOD(uart_flush, ar933x_bus_flush),
333 KOBJMETHOD(uart_getsig, ar933x_bus_getsig),
334 KOBJMETHOD(uart_ioctl, ar933x_bus_ioctl),
335 KOBJMETHOD(uart_ipend, ar933x_bus_ipend),
336 KOBJMETHOD(uart_param, ar933x_bus_param),
337 KOBJMETHOD(uart_probe, ar933x_bus_probe),
338 KOBJMETHOD(uart_receive, ar933x_bus_receive),
339 KOBJMETHOD(uart_setsig, ar933x_bus_setsig),
340 KOBJMETHOD(uart_transmit, ar933x_bus_transmit),
341 { 0, 0 }
342 };
343
344 struct uart_class uart_ar933x_class = {
345 "ar933x",
346 ar933x_methods,
347 sizeof(struct ar933x_softc),
348 .uc_ops = &uart_ar933x_ops,
349 .uc_range = 8,
350 .uc_rclk = DEFAULT_RCLK
351 };
352
353 #define SIGCHG(c, i, s, d) \
354 if (c) { \
355 i |= (i & s) ? s : s | d; \
356 } else { \
357 i = (i & s) ? (i & ~s) | d : i; \
358 }
359
360 static int
361 ar933x_bus_attach(struct uart_softc *sc)
362 {
363 struct ar933x_softc *u = (struct ar933x_softc *)sc;
364 struct uart_bas *bas = &sc->sc_bas;
365 uint32_t reg;
366
367 /* XXX TODO: flush transmitter */
368
369 /*
370 * Setup initial interrupt notifications.
371 *
372 * XXX for now, just RX FIFO valid.
373 * Later on (when they're handled), also handle
374 * RX errors/overflow.
375 */
376 u->u_ier = AR933X_UART_INT_RX_VALID;
377
378 /* Enable RX interrupts to kick-start things */
379 ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier);
380
381 /* Enable the host interrupt now */
382 reg = ar933x_getreg(bas, AR933X_UART_CS_REG);
383 reg |= AR933X_UART_CS_HOST_INT_EN;
384 ar933x_setreg(bas, AR933X_UART_CS_REG, reg);
385
386 return (0);
387 }
388
389 static int
390 ar933x_bus_detach(struct uart_softc *sc)
391 {
392 struct uart_bas *bas = &sc->sc_bas;
393 uint32_t reg;
394
395 /* Disable all interrupts */
396 ar933x_setreg(bas, AR933X_UART_INT_EN_REG, 0x00000000);
397
398 /* Disable the host interrupt */
399 reg = ar933x_getreg(bas, AR933X_UART_CS_REG);
400 reg &= ~AR933X_UART_CS_HOST_INT_EN;
401 ar933x_setreg(bas, AR933X_UART_CS_REG, reg);
402 uart_barrier(bas);
403
404 return (0);
405 }
406
407 static int
408 ar933x_bus_flush(struct uart_softc *sc, int what)
409 {
410 struct uart_bas *bas;
411
412 bas = &sc->sc_bas;
413 uart_lock(sc->sc_hwmtx);
414 ar933x_drain(bas, what);
415 uart_unlock(sc->sc_hwmtx);
416
417 return (0);
418 }
419
420 static int
421 ar933x_bus_getsig(struct uart_softc *sc)
422 {
423 uint32_t sig = sc->sc_hwsig;
424
425 /*
426 * For now, let's just return that DSR/DCD/CTS is asserted.
427 *
428 * XXX TODO: actually verify whether this is correct!
429 */
430 SIGCHG(1, sig, SER_DSR, SER_DDSR);
431 SIGCHG(1, sig, SER_CTS, SER_DCTS);
432 SIGCHG(1, sig, SER_DCD, SER_DDCD);
433 SIGCHG(1, sig, SER_RI, SER_DRI);
434
435 sc->sc_hwsig = sig & ~SER_MASK_DELTA;
436
437 return (sig);
438 }
439
440 static int
441 ar933x_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
442 {
443 #if 0
444 struct uart_bas *bas;
445 int baudrate, divisor, error;
446 uint8_t efr, lcr;
447
448 bas = &sc->sc_bas;
449 error = 0;
450 uart_lock(sc->sc_hwmtx);
451 switch (request) {
452 case UART_IOCTL_BREAK:
453 lcr = uart_getreg(bas, REG_LCR);
454 if (data)
455 lcr |= LCR_SBREAK;
456 else
457 lcr &= ~LCR_SBREAK;
458 uart_setreg(bas, REG_LCR, lcr);
459 uart_barrier(bas);
460 break;
461 case UART_IOCTL_IFLOW:
462 lcr = uart_getreg(bas, REG_LCR);
463 uart_barrier(bas);
464 uart_setreg(bas, REG_LCR, 0xbf);
465 uart_barrier(bas);
466 efr = uart_getreg(bas, REG_EFR);
467 if (data)
468 efr |= EFR_RTS;
469 else
470 efr &= ~EFR_RTS;
471 uart_setreg(bas, REG_EFR, efr);
472 uart_barrier(bas);
473 uart_setreg(bas, REG_LCR, lcr);
474 uart_barrier(bas);
475 break;
476 case UART_IOCTL_OFLOW:
477 lcr = uart_getreg(bas, REG_LCR);
478 uart_barrier(bas);
479 uart_setreg(bas, REG_LCR, 0xbf);
480 uart_barrier(bas);
481 efr = uart_getreg(bas, REG_EFR);
482 if (data)
483 efr |= EFR_CTS;
484 else
485 efr &= ~EFR_CTS;
486 uart_setreg(bas, REG_EFR, efr);
487 uart_barrier(bas);
488 uart_setreg(bas, REG_LCR, lcr);
489 uart_barrier(bas);
490 break;
491 case UART_IOCTL_BAUD:
492 lcr = uart_getreg(bas, REG_LCR);
493 uart_setreg(bas, REG_LCR, lcr | LCR_DLAB);
494 uart_barrier(bas);
495 divisor = uart_getreg(bas, REG_DLL) |
496 (uart_getreg(bas, REG_DLH) << 8);
497 uart_barrier(bas);
498 uart_setreg(bas, REG_LCR, lcr);
499 uart_barrier(bas);
500 baudrate = (divisor > 0) ? bas->rclk / divisor / 16 : 0;
501 if (baudrate > 0)
502 *(int*)data = baudrate;
503 else
504 error = ENXIO;
505 break;
506 default:
507 error = EINVAL;
508 break;
509 }
510 uart_unlock(sc->sc_hwmtx);
511 return (error);
512 #endif
513 return (ENXIO);
514 }
515
516 /*
517 * Bus interrupt handler.
518 *
519 * For now, system interrupts are disabled.
520 * So this is just called from a callout in uart_core.c
521 * to poll various state.
522 */
523 static int
524 ar933x_bus_ipend(struct uart_softc *sc)
525 {
526 struct ar933x_softc *u = (struct ar933x_softc *)sc;
527 struct uart_bas *bas = &sc->sc_bas;
528 int ipend = 0;
529 uint32_t isr;
530
531 uart_lock(sc->sc_hwmtx);
532
533 /*
534 * Fetch/ACK the ISR status.
535 */
536 isr = ar933x_getreg(bas, AR933X_UART_INT_REG);
537 ar933x_setreg(bas, AR933X_UART_INT_REG, isr);
538 uart_barrier(bas);
539
540 /*
541 * RX ready - notify upper layer.
542 */
543 if (isr & AR933X_UART_INT_RX_VALID) {
544 ipend |= SER_INT_RXREADY;
545 }
546
547 /*
548 * If we get this interrupt, we should disable
549 * it from the interrupt mask and inform the uart
550 * driver appropriately.
551 *
552 * We can't keep setting SER_INT_TXIDLE or SER_INT_SIGCHG
553 * all the time or IO stops working. So we will always
554 * clear this interrupt if we get it, then we only signal
555 * the upper layer if we were doing active TX in the
556 * first place.
557 *
558 * Also, the name is misleading. This actually means
559 * "the FIFO is almost empty." So if we just write some
560 * more data to the FIFO without checking whether it can
561 * take said data, we'll overflow the thing.
562 *
563 * Unfortunately the FreeBSD uart device has no concept of
564 * partial UART writes - it expects that the whole buffer
565 * is written to the hardware. Thus for now, ar933x_bus_transmit()
566 * will wait for the FIFO to finish draining before it pushes
567 * more frames into it.
568 */
569 if (isr & AR933X_UART_INT_TX_EMPTY) {
570 /*
571 * Update u_ier to disable TX notifications; update hardware
572 */
573 u->u_ier &= ~AR933X_UART_INT_TX_EMPTY;
574 ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier);
575 uart_barrier(bas);
576 }
577
578 /*
579 * Only signal TX idle if we're not busy transmitting.
580 */
581 if (sc->sc_txbusy) {
582 if (isr & AR933X_UART_INT_TX_EMPTY) {
583 ipend |= SER_INT_TXIDLE;
584 } else {
585 ipend |= SER_INT_SIGCHG;
586 }
587 }
588
589 uart_unlock(sc->sc_hwmtx);
590 return (ipend);
591 }
592
593 static int
594 ar933x_bus_param(struct uart_softc *sc, int baudrate, int databits,
595 int stopbits, int parity)
596 {
597 struct uart_bas *bas;
598 int error;
599
600 bas = &sc->sc_bas;
601 uart_lock(sc->sc_hwmtx);
602 error = ar933x_param(bas, baudrate, databits, stopbits, parity);
603 uart_unlock(sc->sc_hwmtx);
604 return (error);
605 }
606
607 static int
608 ar933x_bus_probe(struct uart_softc *sc)
609 {
610 struct uart_bas *bas;
611 int error;
612
613 bas = &sc->sc_bas;
614
615 error = ar933x_probe(bas);
616 if (error)
617 return (error);
618
619 /* Reset FIFOs. */
620 ar933x_drain(bas, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER);
621
622 /* XXX TODO: actually find out what the FIFO depth is! */
623 sc->sc_rxfifosz = 16;
624 sc->sc_txfifosz = 16;
625
626 return (0);
627 }
628
629 static int
630 ar933x_bus_receive(struct uart_softc *sc)
631 {
632 struct uart_bas *bas = &sc->sc_bas;
633 int xc;
634
635 uart_lock(sc->sc_hwmtx);
636
637 /* Loop over until we are full, or no data is available */
638 while (ar933x_rxready(bas)) {
639 if (uart_rx_full(sc)) {
640 sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
641 break;
642 }
643
644 /* Read the top of the RX FIFO */
645 xc = ar933x_getreg(bas, AR933X_UART_DATA_REG) & 0xff;
646
647 /* Remove that entry from said RX FIFO */
648 ar933x_setreg(bas, AR933X_UART_DATA_REG,
649 AR933X_UART_DATA_RX_CSR);
650 uart_barrier(bas);
651
652 /* XXX frame, parity error */
653 uart_rx_put(sc, xc);
654 }
655
656 /*
657 * XXX TODO: Discard everything left in the Rx FIFO?
658 * XXX only if we've hit an overrun condition?
659 */
660
661 uart_unlock(sc->sc_hwmtx);
662
663 return (0);
664 }
665
666 static int
667 ar933x_bus_setsig(struct uart_softc *sc, int sig)
668 {
669 #if 0
670 struct ar933x_softc *ns8250 = (struct ar933x_softc*)sc;
671 struct uart_bas *bas;
672 uint32_t new, old;
673
674 bas = &sc->sc_bas;
675 do {
676 old = sc->sc_hwsig;
677 new = old;
678 if (sig & SER_DDTR) {
679 SIGCHG(sig & SER_DTR, new, SER_DTR,
680 SER_DDTR);
681 }
682 if (sig & SER_DRTS) {
683 SIGCHG(sig & SER_RTS, new, SER_RTS,
684 SER_DRTS);
685 }
686 } while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
687 uart_lock(sc->sc_hwmtx);
688 ns8250->mcr &= ~(MCR_DTR|MCR_RTS);
689 if (new & SER_DTR)
690 ns8250->mcr |= MCR_DTR;
691 if (new & SER_RTS)
692 ns8250->mcr |= MCR_RTS;
693 uart_setreg(bas, REG_MCR, ns8250->mcr);
694 uart_barrier(bas);
695 uart_unlock(sc->sc_hwmtx);
696 #endif
697 return (0);
698 }
699
700 /*
701 * Write the current transmit buffer to the TX FIFO.
702 *
703 * Unfortunately the FreeBSD uart device has no concept of
704 * partial UART writes - it expects that the whole buffer
705 * is written to the hardware. Thus for now, this will wait for
706 * the FIFO to finish draining before it pushes more frames into it.
707 *
708 * If non-blocking operation is truely needed here, either
709 * the FreeBSD uart device will need to handle partial writes
710 * in xxx_bus_transmit(), or we'll need to do TX FIFO buffering
711 * of our own here.
712 */
713 static int
714 ar933x_bus_transmit(struct uart_softc *sc)
715 {
716 struct uart_bas *bas = &sc->sc_bas;
717 struct ar933x_softc *u = (struct ar933x_softc *)sc;
718 int i;
719
720 uart_lock(sc->sc_hwmtx);
721
722 /* Wait for the FIFO to be clear - see above */
723 while (ar933x_getreg(bas, AR933X_UART_CS_REG) &
724 AR933X_UART_CS_TX_BUSY)
725 ;
726
727 /*
728 * Write some data!
729 */
730 for (i = 0; i < sc->sc_txdatasz; i++) {
731 /* Write the TX data */
732 ar933x_setreg(bas, AR933X_UART_DATA_REG,
733 (sc->sc_txbuf[i] & 0xff) | AR933X_UART_DATA_TX_CSR);
734 uart_barrier(bas);
735 }
736
737 /*
738 * Now that we're transmitting, get interrupt notification
739 * when the FIFO is (almost) empty - see above.
740 */
741 u->u_ier |= AR933X_UART_INT_TX_EMPTY;
742 ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier);
743 uart_barrier(bas);
744
745 /*
746 * Inform the upper layer that we are presently transmitting
747 * data to the hardware; this will be cleared when the
748 * TXIDLE interrupt occurs.
749 */
750 sc->sc_txbusy = 1;
751 uart_unlock(sc->sc_hwmtx);
752
753 return (0);
754 }
Cache object: e2e3bdaea77feede15631b9528aaabfe
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