xref: /openbmc/linux/drivers/macintosh/via-cuda.c (revision da1d9caf)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Device driver for the Cuda and Egret system controllers found on PowerMacs
4  * and 68k Macs.
5  *
6  * The Cuda or Egret is a 6805 microcontroller interfaced to the 6522 VIA.
7  * This MCU controls system power, Parameter RAM, Real Time Clock and the
8  * Apple Desktop Bus (ADB) that connects to the keyboard and mouse.
9  *
10  * Copyright (C) 1996 Paul Mackerras.
11  */
12 #include <linux/stdarg.h>
13 #include <linux/types.h>
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <linux/delay.h>
17 #include <linux/adb.h>
18 #include <linux/cuda.h>
19 #include <linux/spinlock.h>
20 #include <linux/interrupt.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 
24 #ifdef CONFIG_PPC
25 #include <asm/machdep.h>
26 #include <asm/pmac_feature.h>
27 #else
28 #include <asm/macintosh.h>
29 #include <asm/macints.h>
30 #include <asm/mac_via.h>
31 #endif
32 #include <asm/io.h>
33 #include <linux/init.h>
34 
35 static volatile unsigned char __iomem *via;
36 static DEFINE_SPINLOCK(cuda_lock);
37 
38 /* VIA registers - spaced 0x200 bytes apart */
39 #define RS		0x200		/* skip between registers */
40 #define B		0		/* B-side data */
41 #define A		RS		/* A-side data */
42 #define DIRB		(2*RS)		/* B-side direction (1=output) */
43 #define DIRA		(3*RS)		/* A-side direction (1=output) */
44 #define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
45 #define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
46 #define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
47 #define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
48 #define T2CL		(8*RS)		/* Timer 2 ctr/latch (low 8 bits) */
49 #define T2CH		(9*RS)		/* Timer 2 counter (high 8 bits) */
50 #define SR		(10*RS)		/* Shift register */
51 #define ACR		(11*RS)		/* Auxiliary control register */
52 #define PCR		(12*RS)		/* Peripheral control register */
53 #define IFR		(13*RS)		/* Interrupt flag register */
54 #define IER		(14*RS)		/* Interrupt enable register */
55 #define ANH		(15*RS)		/* A-side data, no handshake */
56 
57 /*
58  * When the Cuda design replaced the Egret, some signal names and
59  * logic sense changed. They all serve the same purposes, however.
60  *
61  *   VIA pin       |  Egret pin
62  * ----------------+------------------------------------------
63  *   PB3 (input)   |  Transceiver session   (active low)
64  *   PB4 (output)  |  VIA full              (active high)
65  *   PB5 (output)  |  System session        (active high)
66  *
67  *   VIA pin       |  Cuda pin
68  * ----------------+------------------------------------------
69  *   PB3 (input)   |  Transfer request      (active low)
70  *   PB4 (output)  |  Byte acknowledge      (active low)
71  *   PB5 (output)  |  Transfer in progress  (active low)
72  */
73 
74 /* Bits in Port B data register */
75 #define TREQ		0x08		/* Transfer request */
76 #define TACK		0x10		/* Transfer acknowledge */
77 #define TIP		0x20		/* Transfer in progress */
78 
79 /* Bits in ACR */
80 #define SR_CTRL		0x1c		/* Shift register control bits */
81 #define SR_EXT		0x0c		/* Shift on external clock */
82 #define SR_OUT		0x10		/* Shift out if 1 */
83 
84 /* Bits in IFR and IER */
85 #define IER_SET		0x80		/* set bits in IER */
86 #define IER_CLR		0		/* clear bits in IER */
87 #define SR_INT		0x04		/* Shift register full/empty */
88 
89 /* Duration of byte acknowledgement pulse (us) */
90 #define EGRET_TACK_ASSERTED_DELAY	300
91 #define EGRET_TACK_NEGATED_DELAY	400
92 
93 /* Interval from interrupt to start of session (us) */
94 #define EGRET_SESSION_DELAY		450
95 
96 #ifdef CONFIG_PPC
97 #define mcu_is_egret	false
98 #else
99 static bool mcu_is_egret;
100 #endif
101 
102 static inline bool TREQ_asserted(u8 portb)
103 {
104 	return !(portb & TREQ);
105 }
106 
107 static inline void assert_TIP(void)
108 {
109 	if (mcu_is_egret) {
110 		udelay(EGRET_SESSION_DELAY);
111 		out_8(&via[B], in_8(&via[B]) | TIP);
112 	} else
113 		out_8(&via[B], in_8(&via[B]) & ~TIP);
114 }
115 
116 static inline void assert_TIP_and_TACK(void)
117 {
118 	if (mcu_is_egret) {
119 		udelay(EGRET_SESSION_DELAY);
120 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
121 	} else
122 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
123 }
124 
125 static inline void assert_TACK(void)
126 {
127 	if (mcu_is_egret) {
128 		udelay(EGRET_TACK_NEGATED_DELAY);
129 		out_8(&via[B], in_8(&via[B]) | TACK);
130 	} else
131 		out_8(&via[B], in_8(&via[B]) & ~TACK);
132 }
133 
134 static inline void toggle_TACK(void)
135 {
136 	out_8(&via[B], in_8(&via[B]) ^ TACK);
137 }
138 
139 static inline void negate_TACK(void)
140 {
141 	if (mcu_is_egret) {
142 		udelay(EGRET_TACK_ASSERTED_DELAY);
143 		out_8(&via[B], in_8(&via[B]) & ~TACK);
144 	} else
145 		out_8(&via[B], in_8(&via[B]) | TACK);
146 }
147 
148 static inline void negate_TIP_and_TACK(void)
149 {
150 	if (mcu_is_egret) {
151 		udelay(EGRET_TACK_ASSERTED_DELAY);
152 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
153 	} else
154 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
155 }
156 
157 static enum cuda_state {
158     idle,
159     sent_first_byte,
160     sending,
161     reading,
162     read_done,
163     awaiting_reply
164 } cuda_state;
165 
166 static struct adb_request *current_req;
167 static struct adb_request *last_req;
168 static unsigned char cuda_rbuf[16];
169 static unsigned char *reply_ptr;
170 static int reading_reply;
171 static int data_index;
172 static int cuda_irq;
173 #ifdef CONFIG_PPC
174 static struct device_node *vias;
175 #endif
176 static int cuda_fully_inited;
177 
178 #ifdef CONFIG_ADB
179 static int cuda_probe(void);
180 static int cuda_send_request(struct adb_request *req, int sync);
181 static int cuda_adb_autopoll(int devs);
182 static int cuda_reset_adb_bus(void);
183 #endif /* CONFIG_ADB */
184 
185 static int cuda_init_via(void);
186 static void cuda_start(void);
187 static irqreturn_t cuda_interrupt(int irq, void *arg);
188 static void cuda_input(unsigned char *buf, int nb);
189 void cuda_poll(void);
190 static int cuda_write(struct adb_request *req);
191 
192 int cuda_request(struct adb_request *req,
193 		 void (*done)(struct adb_request *), int nbytes, ...);
194 
195 #ifdef CONFIG_ADB
196 struct adb_driver via_cuda_driver = {
197 	.name         = "CUDA",
198 	.probe        = cuda_probe,
199 	.send_request = cuda_send_request,
200 	.autopoll     = cuda_adb_autopoll,
201 	.poll         = cuda_poll,
202 	.reset_bus    = cuda_reset_adb_bus,
203 };
204 #endif /* CONFIG_ADB */
205 
206 #ifdef CONFIG_MAC
207 int __init find_via_cuda(void)
208 {
209     struct adb_request req;
210     int err;
211 
212     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
213         macintosh_config->adb_type != MAC_ADB_EGRET)
214 	return 0;
215 
216     via = via1;
217     cuda_state = idle;
218     mcu_is_egret = macintosh_config->adb_type == MAC_ADB_EGRET;
219 
220     err = cuda_init_via();
221     if (err) {
222 	printk(KERN_ERR "cuda_init_via() failed\n");
223 	via = NULL;
224 	return 0;
225     }
226 
227     /* enable autopoll */
228     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
229     while (!req.complete)
230 	cuda_poll();
231 
232     return 1;
233 }
234 #else
235 int __init find_via_cuda(void)
236 {
237     struct adb_request req;
238     phys_addr_t taddr;
239     const u32 *reg;
240     int err;
241 
242     if (vias)
243 	return 1;
244     vias = of_find_node_by_name(NULL, "via-cuda");
245     if (!vias)
246 	return 0;
247 
248     reg = of_get_property(vias, "reg", NULL);
249     if (reg == NULL) {
250 	    printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
251 	    goto fail;
252     }
253     taddr = of_translate_address(vias, reg);
254     if (taddr == 0) {
255 	    printk(KERN_ERR "via-cuda: Can't translate address !\n");
256 	    goto fail;
257     }
258     via = ioremap(taddr, 0x2000);
259     if (via == NULL) {
260 	    printk(KERN_ERR "via-cuda: Can't map address !\n");
261 	    goto fail;
262     }
263 
264     cuda_state = idle;
265     sys_ctrler = SYS_CTRLER_CUDA;
266 
267     err = cuda_init_via();
268     if (err) {
269 	printk(KERN_ERR "cuda_init_via() failed\n");
270 	via = NULL;
271 	return 0;
272     }
273 
274     /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
275     /* for us by the main VIA driver in arch/m68k/mac/via.c        */
276 
277     out_8(&via[IFR], 0x7f);	/* clear interrupts by writing 1s */
278     out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
279 
280     /* enable autopoll */
281     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
282     while (!req.complete)
283 	cuda_poll();
284 
285     return 1;
286 
287  fail:
288     of_node_put(vias);
289     vias = NULL;
290     return 0;
291 }
292 #endif /* !defined CONFIG_MAC */
293 
294 static int __init via_cuda_start(void)
295 {
296     if (via == NULL)
297 	return -ENODEV;
298 
299 #ifdef CONFIG_MAC
300     cuda_irq = IRQ_MAC_ADB;
301 #else
302     cuda_irq = irq_of_parse_and_map(vias, 0);
303     if (!cuda_irq) {
304 	printk(KERN_ERR "via-cuda: can't map interrupts for %pOF\n",
305 	       vias);
306 	return -ENODEV;
307     }
308 #endif
309 
310     if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
311 	printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
312 	return -EAGAIN;
313     }
314 
315     pr_info("Macintosh Cuda and Egret driver.\n");
316 
317     cuda_fully_inited = 1;
318     return 0;
319 }
320 
321 device_initcall(via_cuda_start);
322 
323 #ifdef CONFIG_ADB
324 static int
325 cuda_probe(void)
326 {
327 #ifdef CONFIG_PPC
328     if (sys_ctrler != SYS_CTRLER_CUDA)
329 	return -ENODEV;
330 #else
331     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
332         macintosh_config->adb_type != MAC_ADB_EGRET)
333 	return -ENODEV;
334 #endif
335     if (via == NULL)
336 	return -ENODEV;
337     return 0;
338 }
339 #endif /* CONFIG_ADB */
340 
341 static int __init sync_egret(void)
342 {
343 	if (TREQ_asserted(in_8(&via[B]))) {
344 		/* Complete the inbound transfer */
345 		assert_TIP_and_TACK();
346 		while (1) {
347 			negate_TACK();
348 			mdelay(1);
349 			(void)in_8(&via[SR]);
350 			assert_TACK();
351 			if (!TREQ_asserted(in_8(&via[B])))
352 				break;
353 		}
354 		negate_TIP_and_TACK();
355 	} else if (in_8(&via[B]) & TIP) {
356 		/* Terminate the outbound transfer */
357 		negate_TACK();
358 		assert_TACK();
359 		mdelay(1);
360 		negate_TIP_and_TACK();
361 	}
362 	/* Clear shift register interrupt */
363 	if (in_8(&via[IFR]) & SR_INT)
364 		(void)in_8(&via[SR]);
365 	return 0;
366 }
367 
368 #define WAIT_FOR(cond, what)					\
369     do {                                                        \
370     	int x;							\
371 	for (x = 1000; !(cond); --x) {				\
372 	    if (x == 0) {					\
373 		pr_err("Timeout waiting for " what "\n");	\
374 		return -ENXIO;					\
375 	    }							\
376 	    udelay(100);					\
377 	}							\
378     } while (0)
379 
380 static int
381 __init cuda_init_via(void)
382 {
383 #ifdef CONFIG_PPC
384     out_8(&via[IER], 0x7f);					/* disable interrupts from VIA */
385     (void)in_8(&via[IER]);
386 #else
387     out_8(&via[IER], SR_INT);					/* disable SR interrupt from VIA */
388 #endif
389 
390     out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ);	/* TACK & TIP out */
391     out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);	/* SR data in */
392     (void)in_8(&via[SR]);					/* clear any left-over data */
393 
394     if (mcu_is_egret)
395 	return sync_egret();
396 
397     negate_TIP_and_TACK();
398 
399     /* delay 4ms and then clear any pending interrupt */
400     mdelay(4);
401     (void)in_8(&via[SR]);
402     out_8(&via[IFR], SR_INT);
403 
404     /* sync with the CUDA - assert TACK without TIP */
405     assert_TACK();
406 
407     /* wait for the CUDA to assert TREQ in response */
408     WAIT_FOR(TREQ_asserted(in_8(&via[B])), "CUDA response to sync");
409 
410     /* wait for the interrupt and then clear it */
411     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
412     (void)in_8(&via[SR]);
413     out_8(&via[IFR], SR_INT);
414 
415     /* finish the sync by negating TACK */
416     negate_TACK();
417 
418     /* wait for the CUDA to negate TREQ and the corresponding interrupt */
419     WAIT_FOR(!TREQ_asserted(in_8(&via[B])), "CUDA response to sync (3)");
420     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
421     (void)in_8(&via[SR]);
422     out_8(&via[IFR], SR_INT);
423 
424     return 0;
425 }
426 
427 #ifdef CONFIG_ADB
428 /* Send an ADB command */
429 static int
430 cuda_send_request(struct adb_request *req, int sync)
431 {
432     int i;
433 
434     if ((via == NULL) || !cuda_fully_inited) {
435 	req->complete = 1;
436 	return -ENXIO;
437     }
438 
439     req->reply_expected = 1;
440 
441     i = cuda_write(req);
442     if (i)
443 	return i;
444 
445     if (sync) {
446 	while (!req->complete)
447 	    cuda_poll();
448     }
449     return 0;
450 }
451 
452 
453 /* Enable/disable autopolling */
454 static int
455 cuda_adb_autopoll(int devs)
456 {
457     struct adb_request req;
458 
459     if ((via == NULL) || !cuda_fully_inited)
460 	return -ENXIO;
461 
462     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
463     while (!req.complete)
464 	cuda_poll();
465     return 0;
466 }
467 
468 /* Reset adb bus - how do we do this?? */
469 static int
470 cuda_reset_adb_bus(void)
471 {
472     struct adb_request req;
473 
474     if ((via == NULL) || !cuda_fully_inited)
475 	return -ENXIO;
476 
477     cuda_request(&req, NULL, 2, ADB_PACKET, 0);		/* maybe? */
478     while (!req.complete)
479 	cuda_poll();
480     return 0;
481 }
482 #endif /* CONFIG_ADB */
483 
484 /* Construct and send a cuda request */
485 int
486 cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
487 	     int nbytes, ...)
488 {
489     va_list list;
490     int i;
491 
492     if (via == NULL) {
493 	req->complete = 1;
494 	return -ENXIO;
495     }
496 
497     req->nbytes = nbytes;
498     req->done = done;
499     va_start(list, nbytes);
500     for (i = 0; i < nbytes; ++i)
501 	req->data[i] = va_arg(list, int);
502     va_end(list);
503     req->reply_expected = 1;
504     return cuda_write(req);
505 }
506 EXPORT_SYMBOL(cuda_request);
507 
508 static int
509 cuda_write(struct adb_request *req)
510 {
511     unsigned long flags;
512 
513     if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
514 	req->complete = 1;
515 	return -EINVAL;
516     }
517     req->next = NULL;
518     req->sent = 0;
519     req->complete = 0;
520     req->reply_len = 0;
521 
522     spin_lock_irqsave(&cuda_lock, flags);
523     if (current_req) {
524 	last_req->next = req;
525 	last_req = req;
526     } else {
527 	current_req = req;
528 	last_req = req;
529 	if (cuda_state == idle)
530 	    cuda_start();
531     }
532     spin_unlock_irqrestore(&cuda_lock, flags);
533 
534     return 0;
535 }
536 
537 static void
538 cuda_start(void)
539 {
540     /* assert cuda_state == idle */
541     if (current_req == NULL)
542 	return;
543     data_index = 0;
544     if (TREQ_asserted(in_8(&via[B])))
545 	return;			/* a byte is coming in from the CUDA */
546 
547     /* set the shift register to shift out and send a byte */
548     out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
549     out_8(&via[SR], current_req->data[data_index++]);
550     if (mcu_is_egret)
551 	assert_TIP_and_TACK();
552     else
553 	assert_TIP();
554     cuda_state = sent_first_byte;
555 }
556 
557 void
558 cuda_poll(void)
559 {
560 	cuda_interrupt(0, NULL);
561 }
562 EXPORT_SYMBOL(cuda_poll);
563 
564 #define ARRAY_FULL(a, p)	((p) - (a) == ARRAY_SIZE(a))
565 
566 static irqreturn_t
567 cuda_interrupt(int irq, void *arg)
568 {
569     unsigned long flags;
570     u8 status;
571     struct adb_request *req = NULL;
572     unsigned char ibuf[16];
573     int ibuf_len = 0;
574     int complete = 0;
575     bool full;
576 
577     spin_lock_irqsave(&cuda_lock, flags);
578 
579     /* On powermacs, this handler is registered for the VIA IRQ. But they use
580      * just the shift register IRQ -- other VIA interrupt sources are disabled.
581      * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
582      * we are polling, the shift register IRQ flag has already been cleared.
583      */
584 
585 #ifdef CONFIG_MAC
586     if (!arg)
587 #endif
588     {
589         if ((in_8(&via[IFR]) & SR_INT) == 0) {
590             spin_unlock_irqrestore(&cuda_lock, flags);
591             return IRQ_NONE;
592         } else {
593             out_8(&via[IFR], SR_INT);
594         }
595     }
596 
597     status = in_8(&via[B]) & (TIP | TACK | TREQ);
598 
599     switch (cuda_state) {
600     case idle:
601 	/* System controller has unsolicited data for us */
602 	(void)in_8(&via[SR]);
603 idle_state:
604 	assert_TIP();
605 	cuda_state = reading;
606 	reply_ptr = cuda_rbuf;
607 	reading_reply = 0;
608 	break;
609 
610     case awaiting_reply:
611 	/* System controller has reply data for us */
612 	(void)in_8(&via[SR]);
613 	assert_TIP();
614 	cuda_state = reading;
615 	reply_ptr = current_req->reply;
616 	reading_reply = 1;
617 	break;
618 
619     case sent_first_byte:
620 	if (TREQ_asserted(status)) {
621 	    /* collision */
622 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
623 	    (void)in_8(&via[SR]);
624 	    negate_TIP_and_TACK();
625 	    cuda_state = idle;
626 	    /* Egret does not raise an "aborted" interrupt */
627 	    if (mcu_is_egret)
628 		goto idle_state;
629 	} else {
630 	    out_8(&via[SR], current_req->data[data_index++]);
631 	    toggle_TACK();
632 	    if (mcu_is_egret)
633 		assert_TACK();
634 	    cuda_state = sending;
635 	}
636 	break;
637 
638     case sending:
639 	req = current_req;
640 	if (data_index >= req->nbytes) {
641 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
642 	    (void)in_8(&via[SR]);
643 	    negate_TIP_and_TACK();
644 	    req->sent = 1;
645 	    if (req->reply_expected) {
646 		cuda_state = awaiting_reply;
647 	    } else {
648 		current_req = req->next;
649 		complete = 1;
650 		/* not sure about this */
651 		cuda_state = idle;
652 		cuda_start();
653 	    }
654 	} else {
655 	    out_8(&via[SR], req->data[data_index++]);
656 	    toggle_TACK();
657 	    if (mcu_is_egret)
658 		assert_TACK();
659 	}
660 	break;
661 
662     case reading:
663 	full = reading_reply ? ARRAY_FULL(current_req->reply, reply_ptr)
664 	                     : ARRAY_FULL(cuda_rbuf, reply_ptr);
665 	if (full)
666 	    (void)in_8(&via[SR]);
667 	else
668 	    *reply_ptr++ = in_8(&via[SR]);
669 	if (!TREQ_asserted(status) || full) {
670 	    if (mcu_is_egret)
671 		assert_TACK();
672 	    /* that's all folks */
673 	    negate_TIP_and_TACK();
674 	    cuda_state = read_done;
675 	    /* Egret does not raise a "read done" interrupt */
676 	    if (mcu_is_egret)
677 		goto read_done_state;
678 	} else {
679 	    toggle_TACK();
680 	    if (mcu_is_egret)
681 		negate_TACK();
682 	}
683 	break;
684 
685     case read_done:
686 	(void)in_8(&via[SR]);
687 read_done_state:
688 	if (reading_reply) {
689 	    req = current_req;
690 	    req->reply_len = reply_ptr - req->reply;
691 	    if (req->data[0] == ADB_PACKET) {
692 		/* Have to adjust the reply from ADB commands */
693 		if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
694 		    /* the 0x2 bit indicates no response */
695 		    req->reply_len = 0;
696 		} else {
697 		    /* leave just the command and result bytes in the reply */
698 		    req->reply_len -= 2;
699 		    memmove(req->reply, req->reply + 2, req->reply_len);
700 		}
701 	    }
702 	    current_req = req->next;
703 	    complete = 1;
704 	    reading_reply = 0;
705 	} else {
706 	    /* This is tricky. We must break the spinlock to call
707 	     * cuda_input. However, doing so means we might get
708 	     * re-entered from another CPU getting an interrupt
709 	     * or calling cuda_poll(). I ended up using the stack
710 	     * (it's only for 16 bytes) and moving the actual
711 	     * call to cuda_input to outside of the lock.
712 	     */
713 	    ibuf_len = reply_ptr - cuda_rbuf;
714 	    memcpy(ibuf, cuda_rbuf, ibuf_len);
715 	}
716 	reply_ptr = cuda_rbuf;
717 	cuda_state = idle;
718 	cuda_start();
719 	if (cuda_state == idle && TREQ_asserted(in_8(&via[B]))) {
720 	    assert_TIP();
721 	    cuda_state = reading;
722 	}
723 	break;
724 
725     default:
726 	pr_err("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
727     }
728     spin_unlock_irqrestore(&cuda_lock, flags);
729     if (complete && req) {
730     	void (*done)(struct adb_request *) = req->done;
731     	mb();
732     	req->complete = 1;
733     	/* Here, we assume that if the request has a done member, the
734     	 * struct request will survive to setting req->complete to 1
735     	 */
736     	if (done)
737 		(*done)(req);
738     }
739     if (ibuf_len)
740 	cuda_input(ibuf, ibuf_len);
741     return IRQ_HANDLED;
742 }
743 
744 static void
745 cuda_input(unsigned char *buf, int nb)
746 {
747     switch (buf[0]) {
748     case ADB_PACKET:
749 #ifdef CONFIG_XMON
750 	if (nb == 5 && buf[2] == 0x2c) {
751 	    extern int xmon_wants_key, xmon_adb_keycode;
752 	    if (xmon_wants_key) {
753 		xmon_adb_keycode = buf[3];
754 		return;
755 	    }
756 	}
757 #endif /* CONFIG_XMON */
758 #ifdef CONFIG_ADB
759 	adb_input(buf+2, nb-2, buf[1] & 0x40);
760 #endif /* CONFIG_ADB */
761 	break;
762 
763     case TIMER_PACKET:
764 	/* Egret sends these periodically. Might be useful as a 'heartbeat'
765 	 * to trigger a recovery for the VIA shift register errata.
766 	 */
767 	break;
768 
769     default:
770 	print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1,
771 	               buf, nb, false);
772     }
773 }
774 
775 /* Offset between Unix time (1970-based) and Mac time (1904-based) */
776 #define RTC_OFFSET	2082844800
777 
778 time64_t cuda_get_time(void)
779 {
780 	struct adb_request req;
781 	u32 now;
782 
783 	if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
784 		return 0;
785 	while (!req.complete)
786 		cuda_poll();
787 	if (req.reply_len != 7)
788 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
789 	now = (req.reply[3] << 24) + (req.reply[4] << 16) +
790 	      (req.reply[5] << 8) + req.reply[6];
791 	return (time64_t)now - RTC_OFFSET;
792 }
793 
794 int cuda_set_rtc_time(struct rtc_time *tm)
795 {
796 	u32 now;
797 	struct adb_request req;
798 
799 	now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
800 	if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
801 	                 now >> 24, now >> 16, now >> 8, now) < 0)
802 		return -ENXIO;
803 	while (!req.complete)
804 		cuda_poll();
805 	if ((req.reply_len != 3) && (req.reply_len != 7))
806 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
807 	return 0;
808 }
809