xref: /linux/drivers/macintosh/via-cuda.c (revision 9052e9c95d908d6c3d7570aadc8898e1d871c8bb)
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 #ifdef CONFIG_PPC
22 #include <asm/prom.h>
23 #include <asm/machdep.h>
24 #else
25 #include <asm/macintosh.h>
26 #include <asm/macints.h>
27 #include <asm/mac_via.h>
28 #endif
29 #include <asm/io.h>
30 #include <linux/init.h>
31 
32 static volatile unsigned char __iomem *via;
33 static DEFINE_SPINLOCK(cuda_lock);
34 
35 /* VIA registers - spaced 0x200 bytes apart */
36 #define RS		0x200		/* skip between registers */
37 #define B		0		/* B-side data */
38 #define A		RS		/* A-side data */
39 #define DIRB		(2*RS)		/* B-side direction (1=output) */
40 #define DIRA		(3*RS)		/* A-side direction (1=output) */
41 #define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
42 #define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
43 #define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
44 #define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
45 #define T2CL		(8*RS)		/* Timer 2 ctr/latch (low 8 bits) */
46 #define T2CH		(9*RS)		/* Timer 2 counter (high 8 bits) */
47 #define SR		(10*RS)		/* Shift register */
48 #define ACR		(11*RS)		/* Auxiliary control register */
49 #define PCR		(12*RS)		/* Peripheral control register */
50 #define IFR		(13*RS)		/* Interrupt flag register */
51 #define IER		(14*RS)		/* Interrupt enable register */
52 #define ANH		(15*RS)		/* A-side data, no handshake */
53 
54 /*
55  * When the Cuda design replaced the Egret, some signal names and
56  * logic sense changed. They all serve the same purposes, however.
57  *
58  *   VIA pin       |  Egret pin
59  * ----------------+------------------------------------------
60  *   PB3 (input)   |  Transceiver session   (active low)
61  *   PB4 (output)  |  VIA full              (active high)
62  *   PB5 (output)  |  System session        (active high)
63  *
64  *   VIA pin       |  Cuda pin
65  * ----------------+------------------------------------------
66  *   PB3 (input)   |  Transfer request      (active low)
67  *   PB4 (output)  |  Byte acknowledge      (active low)
68  *   PB5 (output)  |  Transfer in progress  (active low)
69  */
70 
71 /* Bits in Port B data register */
72 #define TREQ		0x08		/* Transfer request */
73 #define TACK		0x10		/* Transfer acknowledge */
74 #define TIP		0x20		/* Transfer in progress */
75 
76 /* Bits in ACR */
77 #define SR_CTRL		0x1c		/* Shift register control bits */
78 #define SR_EXT		0x0c		/* Shift on external clock */
79 #define SR_OUT		0x10		/* Shift out if 1 */
80 
81 /* Bits in IFR and IER */
82 #define IER_SET		0x80		/* set bits in IER */
83 #define IER_CLR		0		/* clear bits in IER */
84 #define SR_INT		0x04		/* Shift register full/empty */
85 
86 /* Duration of byte acknowledgement pulse (us) */
87 #define EGRET_TACK_ASSERTED_DELAY	300
88 #define EGRET_TACK_NEGATED_DELAY	400
89 
90 /* Interval from interrupt to start of session (us) */
91 #define EGRET_SESSION_DELAY		450
92 
93 #ifdef CONFIG_PPC
94 #define mcu_is_egret	false
95 #else
96 static bool mcu_is_egret;
97 #endif
98 
99 static inline bool TREQ_asserted(u8 portb)
100 {
101 	return !(portb & TREQ);
102 }
103 
104 static inline void assert_TIP(void)
105 {
106 	if (mcu_is_egret) {
107 		udelay(EGRET_SESSION_DELAY);
108 		out_8(&via[B], in_8(&via[B]) | TIP);
109 	} else
110 		out_8(&via[B], in_8(&via[B]) & ~TIP);
111 }
112 
113 static inline void assert_TIP_and_TACK(void)
114 {
115 	if (mcu_is_egret) {
116 		udelay(EGRET_SESSION_DELAY);
117 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
118 	} else
119 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
120 }
121 
122 static inline void assert_TACK(void)
123 {
124 	if (mcu_is_egret) {
125 		udelay(EGRET_TACK_NEGATED_DELAY);
126 		out_8(&via[B], in_8(&via[B]) | TACK);
127 	} else
128 		out_8(&via[B], in_8(&via[B]) & ~TACK);
129 }
130 
131 static inline void toggle_TACK(void)
132 {
133 	out_8(&via[B], in_8(&via[B]) ^ TACK);
134 }
135 
136 static inline void negate_TACK(void)
137 {
138 	if (mcu_is_egret) {
139 		udelay(EGRET_TACK_ASSERTED_DELAY);
140 		out_8(&via[B], in_8(&via[B]) & ~TACK);
141 	} else
142 		out_8(&via[B], in_8(&via[B]) | TACK);
143 }
144 
145 static inline void negate_TIP_and_TACK(void)
146 {
147 	if (mcu_is_egret) {
148 		udelay(EGRET_TACK_ASSERTED_DELAY);
149 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
150 	} else
151 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
152 }
153 
154 static enum cuda_state {
155     idle,
156     sent_first_byte,
157     sending,
158     reading,
159     read_done,
160     awaiting_reply
161 } cuda_state;
162 
163 static struct adb_request *current_req;
164 static struct adb_request *last_req;
165 static unsigned char cuda_rbuf[16];
166 static unsigned char *reply_ptr;
167 static int reading_reply;
168 static int data_index;
169 static int cuda_irq;
170 #ifdef CONFIG_PPC
171 static struct device_node *vias;
172 #endif
173 static int cuda_fully_inited;
174 
175 #ifdef CONFIG_ADB
176 static int cuda_probe(void);
177 static int cuda_send_request(struct adb_request *req, int sync);
178 static int cuda_adb_autopoll(int devs);
179 static int cuda_reset_adb_bus(void);
180 #endif /* CONFIG_ADB */
181 
182 static int cuda_init_via(void);
183 static void cuda_start(void);
184 static irqreturn_t cuda_interrupt(int irq, void *arg);
185 static void cuda_input(unsigned char *buf, int nb);
186 void cuda_poll(void);
187 static int cuda_write(struct adb_request *req);
188 
189 int cuda_request(struct adb_request *req,
190 		 void (*done)(struct adb_request *), int nbytes, ...);
191 
192 #ifdef CONFIG_ADB
193 struct adb_driver via_cuda_driver = {
194 	.name         = "CUDA",
195 	.probe        = cuda_probe,
196 	.send_request = cuda_send_request,
197 	.autopoll     = cuda_adb_autopoll,
198 	.poll         = cuda_poll,
199 	.reset_bus    = cuda_reset_adb_bus,
200 };
201 #endif /* CONFIG_ADB */
202 
203 #ifdef CONFIG_MAC
204 int __init find_via_cuda(void)
205 {
206     struct adb_request req;
207     int err;
208 
209     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
210         macintosh_config->adb_type != MAC_ADB_EGRET)
211 	return 0;
212 
213     via = via1;
214     cuda_state = idle;
215     mcu_is_egret = macintosh_config->adb_type == MAC_ADB_EGRET;
216 
217     err = cuda_init_via();
218     if (err) {
219 	printk(KERN_ERR "cuda_init_via() failed\n");
220 	via = NULL;
221 	return 0;
222     }
223 
224     /* enable autopoll */
225     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
226     while (!req.complete)
227 	cuda_poll();
228 
229     return 1;
230 }
231 #else
232 int __init find_via_cuda(void)
233 {
234     struct adb_request req;
235     phys_addr_t taddr;
236     const u32 *reg;
237     int err;
238 
239     if (vias != 0)
240 	return 1;
241     vias = of_find_node_by_name(NULL, "via-cuda");
242     if (vias == 0)
243 	return 0;
244 
245     reg = of_get_property(vias, "reg", NULL);
246     if (reg == NULL) {
247 	    printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
248 	    goto fail;
249     }
250     taddr = of_translate_address(vias, reg);
251     if (taddr == 0) {
252 	    printk(KERN_ERR "via-cuda: Can't translate address !\n");
253 	    goto fail;
254     }
255     via = ioremap(taddr, 0x2000);
256     if (via == NULL) {
257 	    printk(KERN_ERR "via-cuda: Can't map address !\n");
258 	    goto fail;
259     }
260 
261     cuda_state = idle;
262     sys_ctrler = SYS_CTRLER_CUDA;
263 
264     err = cuda_init_via();
265     if (err) {
266 	printk(KERN_ERR "cuda_init_via() failed\n");
267 	via = NULL;
268 	return 0;
269     }
270 
271     /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
272     /* for us by the main VIA driver in arch/m68k/mac/via.c        */
273 
274     out_8(&via[IFR], 0x7f);	/* clear interrupts by writing 1s */
275     out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
276 
277     /* enable autopoll */
278     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
279     while (!req.complete)
280 	cuda_poll();
281 
282     return 1;
283 
284  fail:
285     of_node_put(vias);
286     vias = NULL;
287     return 0;
288 }
289 #endif /* !defined CONFIG_MAC */
290 
291 static int __init via_cuda_start(void)
292 {
293     if (via == NULL)
294 	return -ENODEV;
295 
296 #ifdef CONFIG_MAC
297     cuda_irq = IRQ_MAC_ADB;
298 #else
299     cuda_irq = irq_of_parse_and_map(vias, 0);
300     if (!cuda_irq) {
301 	printk(KERN_ERR "via-cuda: can't map interrupts for %pOF\n",
302 	       vias);
303 	return -ENODEV;
304     }
305 #endif
306 
307     if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
308 	printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
309 	return -EAGAIN;
310     }
311 
312     pr_info("Macintosh Cuda and Egret driver.\n");
313 
314     cuda_fully_inited = 1;
315     return 0;
316 }
317 
318 device_initcall(via_cuda_start);
319 
320 #ifdef CONFIG_ADB
321 static int
322 cuda_probe(void)
323 {
324 #ifdef CONFIG_PPC
325     if (sys_ctrler != SYS_CTRLER_CUDA)
326 	return -ENODEV;
327 #else
328     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
329         macintosh_config->adb_type != MAC_ADB_EGRET)
330 	return -ENODEV;
331 #endif
332     if (via == NULL)
333 	return -ENODEV;
334     return 0;
335 }
336 #endif /* CONFIG_ADB */
337 
338 static int __init sync_egret(void)
339 {
340 	if (TREQ_asserted(in_8(&via[B]))) {
341 		/* Complete the inbound transfer */
342 		assert_TIP_and_TACK();
343 		while (1) {
344 			negate_TACK();
345 			mdelay(1);
346 			(void)in_8(&via[SR]);
347 			assert_TACK();
348 			if (!TREQ_asserted(in_8(&via[B])))
349 				break;
350 		}
351 		negate_TIP_and_TACK();
352 	} else if (in_8(&via[B]) & TIP) {
353 		/* Terminate the outbound transfer */
354 		negate_TACK();
355 		assert_TACK();
356 		mdelay(1);
357 		negate_TIP_and_TACK();
358 	}
359 	/* Clear shift register interrupt */
360 	if (in_8(&via[IFR]) & SR_INT)
361 		(void)in_8(&via[SR]);
362 	return 0;
363 }
364 
365 #define WAIT_FOR(cond, what)					\
366     do {                                                        \
367     	int x;							\
368 	for (x = 1000; !(cond); --x) {				\
369 	    if (x == 0) {					\
370 		pr_err("Timeout waiting for " what "\n");	\
371 		return -ENXIO;					\
372 	    }							\
373 	    udelay(100);					\
374 	}							\
375     } while (0)
376 
377 static int
378 __init cuda_init_via(void)
379 {
380 #ifdef CONFIG_PPC
381     out_8(&via[IER], 0x7f);					/* disable interrupts from VIA */
382     (void)in_8(&via[IER]);
383 #else
384     out_8(&via[IER], SR_INT);					/* disable SR interrupt from VIA */
385 #endif
386 
387     out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ);	/* TACK & TIP out */
388     out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);	/* SR data in */
389     (void)in_8(&via[SR]);					/* clear any left-over data */
390 
391     if (mcu_is_egret)
392 	return sync_egret();
393 
394     negate_TIP_and_TACK();
395 
396     /* delay 4ms and then clear any pending interrupt */
397     mdelay(4);
398     (void)in_8(&via[SR]);
399     out_8(&via[IFR], SR_INT);
400 
401     /* sync with the CUDA - assert TACK without TIP */
402     assert_TACK();
403 
404     /* wait for the CUDA to assert TREQ in response */
405     WAIT_FOR(TREQ_asserted(in_8(&via[B])), "CUDA response to sync");
406 
407     /* wait for the interrupt and then clear it */
408     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
409     (void)in_8(&via[SR]);
410     out_8(&via[IFR], SR_INT);
411 
412     /* finish the sync by negating TACK */
413     negate_TACK();
414 
415     /* wait for the CUDA to negate TREQ and the corresponding interrupt */
416     WAIT_FOR(!TREQ_asserted(in_8(&via[B])), "CUDA response to sync (3)");
417     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
418     (void)in_8(&via[SR]);
419     out_8(&via[IFR], SR_INT);
420 
421     return 0;
422 }
423 
424 #ifdef CONFIG_ADB
425 /* Send an ADB command */
426 static int
427 cuda_send_request(struct adb_request *req, int sync)
428 {
429     int i;
430 
431     if ((via == NULL) || !cuda_fully_inited) {
432 	req->complete = 1;
433 	return -ENXIO;
434     }
435 
436     req->reply_expected = 1;
437 
438     i = cuda_write(req);
439     if (i)
440 	return i;
441 
442     if (sync) {
443 	while (!req->complete)
444 	    cuda_poll();
445     }
446     return 0;
447 }
448 
449 
450 /* Enable/disable autopolling */
451 static int
452 cuda_adb_autopoll(int devs)
453 {
454     struct adb_request req;
455 
456     if ((via == NULL) || !cuda_fully_inited)
457 	return -ENXIO;
458 
459     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
460     while (!req.complete)
461 	cuda_poll();
462     return 0;
463 }
464 
465 /* Reset adb bus - how do we do this?? */
466 static int
467 cuda_reset_adb_bus(void)
468 {
469     struct adb_request req;
470 
471     if ((via == NULL) || !cuda_fully_inited)
472 	return -ENXIO;
473 
474     cuda_request(&req, NULL, 2, ADB_PACKET, 0);		/* maybe? */
475     while (!req.complete)
476 	cuda_poll();
477     return 0;
478 }
479 #endif /* CONFIG_ADB */
480 
481 /* Construct and send a cuda request */
482 int
483 cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
484 	     int nbytes, ...)
485 {
486     va_list list;
487     int i;
488 
489     if (via == NULL) {
490 	req->complete = 1;
491 	return -ENXIO;
492     }
493 
494     req->nbytes = nbytes;
495     req->done = done;
496     va_start(list, nbytes);
497     for (i = 0; i < nbytes; ++i)
498 	req->data[i] = va_arg(list, int);
499     va_end(list);
500     req->reply_expected = 1;
501     return cuda_write(req);
502 }
503 EXPORT_SYMBOL(cuda_request);
504 
505 static int
506 cuda_write(struct adb_request *req)
507 {
508     unsigned long flags;
509 
510     if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
511 	req->complete = 1;
512 	return -EINVAL;
513     }
514     req->next = NULL;
515     req->sent = 0;
516     req->complete = 0;
517     req->reply_len = 0;
518 
519     spin_lock_irqsave(&cuda_lock, flags);
520     if (current_req != 0) {
521 	last_req->next = req;
522 	last_req = req;
523     } else {
524 	current_req = req;
525 	last_req = req;
526 	if (cuda_state == idle)
527 	    cuda_start();
528     }
529     spin_unlock_irqrestore(&cuda_lock, flags);
530 
531     return 0;
532 }
533 
534 static void
535 cuda_start(void)
536 {
537     /* assert cuda_state == idle */
538     if (current_req == NULL)
539 	return;
540     data_index = 0;
541     if (TREQ_asserted(in_8(&via[B])))
542 	return;			/* a byte is coming in from the CUDA */
543 
544     /* set the shift register to shift out and send a byte */
545     out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
546     out_8(&via[SR], current_req->data[data_index++]);
547     if (mcu_is_egret)
548 	assert_TIP_and_TACK();
549     else
550 	assert_TIP();
551     cuda_state = sent_first_byte;
552 }
553 
554 void
555 cuda_poll(void)
556 {
557 	cuda_interrupt(0, NULL);
558 }
559 EXPORT_SYMBOL(cuda_poll);
560 
561 #define ARRAY_FULL(a, p)	((p) - (a) == ARRAY_SIZE(a))
562 
563 static irqreturn_t
564 cuda_interrupt(int irq, void *arg)
565 {
566     unsigned long flags;
567     u8 status;
568     struct adb_request *req = NULL;
569     unsigned char ibuf[16];
570     int ibuf_len = 0;
571     int complete = 0;
572     bool full;
573 
574     spin_lock_irqsave(&cuda_lock, flags);
575 
576     /* On powermacs, this handler is registered for the VIA IRQ. But they use
577      * just the shift register IRQ -- other VIA interrupt sources are disabled.
578      * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
579      * we are polling, the shift register IRQ flag has already been cleared.
580      */
581 
582 #ifdef CONFIG_MAC
583     if (!arg)
584 #endif
585     {
586         if ((in_8(&via[IFR]) & SR_INT) == 0) {
587             spin_unlock_irqrestore(&cuda_lock, flags);
588             return IRQ_NONE;
589         } else {
590             out_8(&via[IFR], SR_INT);
591         }
592     }
593 
594     status = in_8(&via[B]) & (TIP | TACK | TREQ);
595 
596     switch (cuda_state) {
597     case idle:
598 	/* System controller has unsolicited data for us */
599 	(void)in_8(&via[SR]);
600 idle_state:
601 	assert_TIP();
602 	cuda_state = reading;
603 	reply_ptr = cuda_rbuf;
604 	reading_reply = 0;
605 	break;
606 
607     case awaiting_reply:
608 	/* System controller has reply data for us */
609 	(void)in_8(&via[SR]);
610 	assert_TIP();
611 	cuda_state = reading;
612 	reply_ptr = current_req->reply;
613 	reading_reply = 1;
614 	break;
615 
616     case sent_first_byte:
617 	if (TREQ_asserted(status)) {
618 	    /* collision */
619 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
620 	    (void)in_8(&via[SR]);
621 	    negate_TIP_and_TACK();
622 	    cuda_state = idle;
623 	    /* Egret does not raise an "aborted" interrupt */
624 	    if (mcu_is_egret)
625 		goto idle_state;
626 	} else {
627 	    out_8(&via[SR], current_req->data[data_index++]);
628 	    toggle_TACK();
629 	    if (mcu_is_egret)
630 		assert_TACK();
631 	    cuda_state = sending;
632 	}
633 	break;
634 
635     case sending:
636 	req = current_req;
637 	if (data_index >= req->nbytes) {
638 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
639 	    (void)in_8(&via[SR]);
640 	    negate_TIP_and_TACK();
641 	    req->sent = 1;
642 	    if (req->reply_expected) {
643 		cuda_state = awaiting_reply;
644 	    } else {
645 		current_req = req->next;
646 		complete = 1;
647 		/* not sure about this */
648 		cuda_state = idle;
649 		cuda_start();
650 	    }
651 	} else {
652 	    out_8(&via[SR], req->data[data_index++]);
653 	    toggle_TACK();
654 	    if (mcu_is_egret)
655 		assert_TACK();
656 	}
657 	break;
658 
659     case reading:
660 	full = reading_reply ? ARRAY_FULL(current_req->reply, reply_ptr)
661 	                     : ARRAY_FULL(cuda_rbuf, reply_ptr);
662 	if (full)
663 	    (void)in_8(&via[SR]);
664 	else
665 	    *reply_ptr++ = in_8(&via[SR]);
666 	if (!TREQ_asserted(status) || full) {
667 	    if (mcu_is_egret)
668 		assert_TACK();
669 	    /* that's all folks */
670 	    negate_TIP_and_TACK();
671 	    cuda_state = read_done;
672 	    /* Egret does not raise a "read done" interrupt */
673 	    if (mcu_is_egret)
674 		goto read_done_state;
675 	} else {
676 	    toggle_TACK();
677 	    if (mcu_is_egret)
678 		negate_TACK();
679 	}
680 	break;
681 
682     case read_done:
683 	(void)in_8(&via[SR]);
684 read_done_state:
685 	if (reading_reply) {
686 	    req = current_req;
687 	    req->reply_len = reply_ptr - req->reply;
688 	    if (req->data[0] == ADB_PACKET) {
689 		/* Have to adjust the reply from ADB commands */
690 		if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
691 		    /* the 0x2 bit indicates no response */
692 		    req->reply_len = 0;
693 		} else {
694 		    /* leave just the command and result bytes in the reply */
695 		    req->reply_len -= 2;
696 		    memmove(req->reply, req->reply + 2, req->reply_len);
697 		}
698 	    }
699 	    current_req = req->next;
700 	    complete = 1;
701 	    reading_reply = 0;
702 	} else {
703 	    /* This is tricky. We must break the spinlock to call
704 	     * cuda_input. However, doing so means we might get
705 	     * re-entered from another CPU getting an interrupt
706 	     * or calling cuda_poll(). I ended up using the stack
707 	     * (it's only for 16 bytes) and moving the actual
708 	     * call to cuda_input to outside of the lock.
709 	     */
710 	    ibuf_len = reply_ptr - cuda_rbuf;
711 	    memcpy(ibuf, cuda_rbuf, ibuf_len);
712 	}
713 	reply_ptr = cuda_rbuf;
714 	cuda_state = idle;
715 	cuda_start();
716 	if (cuda_state == idle && TREQ_asserted(in_8(&via[B]))) {
717 	    assert_TIP();
718 	    cuda_state = reading;
719 	}
720 	break;
721 
722     default:
723 	pr_err("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
724     }
725     spin_unlock_irqrestore(&cuda_lock, flags);
726     if (complete && req) {
727     	void (*done)(struct adb_request *) = req->done;
728     	mb();
729     	req->complete = 1;
730     	/* Here, we assume that if the request has a done member, the
731     	 * struct request will survive to setting req->complete to 1
732     	 */
733     	if (done)
734 		(*done)(req);
735     }
736     if (ibuf_len)
737 	cuda_input(ibuf, ibuf_len);
738     return IRQ_HANDLED;
739 }
740 
741 static void
742 cuda_input(unsigned char *buf, int nb)
743 {
744     switch (buf[0]) {
745     case ADB_PACKET:
746 #ifdef CONFIG_XMON
747 	if (nb == 5 && buf[2] == 0x2c) {
748 	    extern int xmon_wants_key, xmon_adb_keycode;
749 	    if (xmon_wants_key) {
750 		xmon_adb_keycode = buf[3];
751 		return;
752 	    }
753 	}
754 #endif /* CONFIG_XMON */
755 #ifdef CONFIG_ADB
756 	adb_input(buf+2, nb-2, buf[1] & 0x40);
757 #endif /* CONFIG_ADB */
758 	break;
759 
760     case TIMER_PACKET:
761 	/* Egret sends these periodically. Might be useful as a 'heartbeat'
762 	 * to trigger a recovery for the VIA shift register errata.
763 	 */
764 	break;
765 
766     default:
767 	print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1,
768 	               buf, nb, false);
769     }
770 }
771 
772 /* Offset between Unix time (1970-based) and Mac time (1904-based) */
773 #define RTC_OFFSET	2082844800
774 
775 time64_t cuda_get_time(void)
776 {
777 	struct adb_request req;
778 	u32 now;
779 
780 	if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
781 		return 0;
782 	while (!req.complete)
783 		cuda_poll();
784 	if (req.reply_len != 7)
785 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
786 	now = (req.reply[3] << 24) + (req.reply[4] << 16) +
787 	      (req.reply[5] << 8) + req.reply[6];
788 	return (time64_t)now - RTC_OFFSET;
789 }
790 
791 int cuda_set_rtc_time(struct rtc_time *tm)
792 {
793 	u32 now;
794 	struct adb_request req;
795 
796 	now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
797 	if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
798 	                 now >> 24, now >> 16, now >> 8, now) < 0)
799 		return -ENXIO;
800 	while (!req.complete)
801 		cuda_poll();
802 	if ((req.reply_len != 3) && (req.reply_len != 7))
803 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
804 	return 0;
805 }
806