xref: /openbmc/linux/drivers/macintosh/via-cuda.c (revision 09de5cd2)
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 #include <asm/pmac_feature.h>
25 #else
26 #include <asm/macintosh.h>
27 #include <asm/macints.h>
28 #include <asm/mac_via.h>
29 #endif
30 #include <asm/io.h>
31 #include <linux/init.h>
32 
33 static volatile unsigned char __iomem *via;
34 static DEFINE_SPINLOCK(cuda_lock);
35 
36 /* VIA registers - spaced 0x200 bytes apart */
37 #define RS		0x200		/* skip between registers */
38 #define B		0		/* B-side data */
39 #define A		RS		/* A-side data */
40 #define DIRB		(2*RS)		/* B-side direction (1=output) */
41 #define DIRA		(3*RS)		/* A-side direction (1=output) */
42 #define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
43 #define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
44 #define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
45 #define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
46 #define T2CL		(8*RS)		/* Timer 2 ctr/latch (low 8 bits) */
47 #define T2CH		(9*RS)		/* Timer 2 counter (high 8 bits) */
48 #define SR		(10*RS)		/* Shift register */
49 #define ACR		(11*RS)		/* Auxiliary control register */
50 #define PCR		(12*RS)		/* Peripheral control register */
51 #define IFR		(13*RS)		/* Interrupt flag register */
52 #define IER		(14*RS)		/* Interrupt enable register */
53 #define ANH		(15*RS)		/* A-side data, no handshake */
54 
55 /*
56  * When the Cuda design replaced the Egret, some signal names and
57  * logic sense changed. They all serve the same purposes, however.
58  *
59  *   VIA pin       |  Egret pin
60  * ----------------+------------------------------------------
61  *   PB3 (input)   |  Transceiver session   (active low)
62  *   PB4 (output)  |  VIA full              (active high)
63  *   PB5 (output)  |  System session        (active high)
64  *
65  *   VIA pin       |  Cuda pin
66  * ----------------+------------------------------------------
67  *   PB3 (input)   |  Transfer request      (active low)
68  *   PB4 (output)  |  Byte acknowledge      (active low)
69  *   PB5 (output)  |  Transfer in progress  (active low)
70  */
71 
72 /* Bits in Port B data register */
73 #define TREQ		0x08		/* Transfer request */
74 #define TACK		0x10		/* Transfer acknowledge */
75 #define TIP		0x20		/* Transfer in progress */
76 
77 /* Bits in ACR */
78 #define SR_CTRL		0x1c		/* Shift register control bits */
79 #define SR_EXT		0x0c		/* Shift on external clock */
80 #define SR_OUT		0x10		/* Shift out if 1 */
81 
82 /* Bits in IFR and IER */
83 #define IER_SET		0x80		/* set bits in IER */
84 #define IER_CLR		0		/* clear bits in IER */
85 #define SR_INT		0x04		/* Shift register full/empty */
86 
87 /* Duration of byte acknowledgement pulse (us) */
88 #define EGRET_TACK_ASSERTED_DELAY	300
89 #define EGRET_TACK_NEGATED_DELAY	400
90 
91 /* Interval from interrupt to start of session (us) */
92 #define EGRET_SESSION_DELAY		450
93 
94 #ifdef CONFIG_PPC
95 #define mcu_is_egret	false
96 #else
97 static bool mcu_is_egret;
98 #endif
99 
100 static inline bool TREQ_asserted(u8 portb)
101 {
102 	return !(portb & TREQ);
103 }
104 
105 static inline void assert_TIP(void)
106 {
107 	if (mcu_is_egret) {
108 		udelay(EGRET_SESSION_DELAY);
109 		out_8(&via[B], in_8(&via[B]) | TIP);
110 	} else
111 		out_8(&via[B], in_8(&via[B]) & ~TIP);
112 }
113 
114 static inline void assert_TIP_and_TACK(void)
115 {
116 	if (mcu_is_egret) {
117 		udelay(EGRET_SESSION_DELAY);
118 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
119 	} else
120 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
121 }
122 
123 static inline void assert_TACK(void)
124 {
125 	if (mcu_is_egret) {
126 		udelay(EGRET_TACK_NEGATED_DELAY);
127 		out_8(&via[B], in_8(&via[B]) | TACK);
128 	} else
129 		out_8(&via[B], in_8(&via[B]) & ~TACK);
130 }
131 
132 static inline void toggle_TACK(void)
133 {
134 	out_8(&via[B], in_8(&via[B]) ^ TACK);
135 }
136 
137 static inline void negate_TACK(void)
138 {
139 	if (mcu_is_egret) {
140 		udelay(EGRET_TACK_ASSERTED_DELAY);
141 		out_8(&via[B], in_8(&via[B]) & ~TACK);
142 	} else
143 		out_8(&via[B], in_8(&via[B]) | TACK);
144 }
145 
146 static inline void negate_TIP_and_TACK(void)
147 {
148 	if (mcu_is_egret) {
149 		udelay(EGRET_TACK_ASSERTED_DELAY);
150 		out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
151 	} else
152 		out_8(&via[B], in_8(&via[B]) | TIP | TACK);
153 }
154 
155 static enum cuda_state {
156     idle,
157     sent_first_byte,
158     sending,
159     reading,
160     read_done,
161     awaiting_reply
162 } cuda_state;
163 
164 static struct adb_request *current_req;
165 static struct adb_request *last_req;
166 static unsigned char cuda_rbuf[16];
167 static unsigned char *reply_ptr;
168 static int reading_reply;
169 static int data_index;
170 static int cuda_irq;
171 #ifdef CONFIG_PPC
172 static struct device_node *vias;
173 #endif
174 static int cuda_fully_inited;
175 
176 #ifdef CONFIG_ADB
177 static int cuda_probe(void);
178 static int cuda_send_request(struct adb_request *req, int sync);
179 static int cuda_adb_autopoll(int devs);
180 static int cuda_reset_adb_bus(void);
181 #endif /* CONFIG_ADB */
182 
183 static int cuda_init_via(void);
184 static void cuda_start(void);
185 static irqreturn_t cuda_interrupt(int irq, void *arg);
186 static void cuda_input(unsigned char *buf, int nb);
187 void cuda_poll(void);
188 static int cuda_write(struct adb_request *req);
189 
190 int cuda_request(struct adb_request *req,
191 		 void (*done)(struct adb_request *), int nbytes, ...);
192 
193 #ifdef CONFIG_ADB
194 struct adb_driver via_cuda_driver = {
195 	.name         = "CUDA",
196 	.probe        = cuda_probe,
197 	.send_request = cuda_send_request,
198 	.autopoll     = cuda_adb_autopoll,
199 	.poll         = cuda_poll,
200 	.reset_bus    = cuda_reset_adb_bus,
201 };
202 #endif /* CONFIG_ADB */
203 
204 #ifdef CONFIG_MAC
205 int __init find_via_cuda(void)
206 {
207     struct adb_request req;
208     int err;
209 
210     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
211         macintosh_config->adb_type != MAC_ADB_EGRET)
212 	return 0;
213 
214     via = via1;
215     cuda_state = idle;
216     mcu_is_egret = macintosh_config->adb_type == MAC_ADB_EGRET;
217 
218     err = cuda_init_via();
219     if (err) {
220 	printk(KERN_ERR "cuda_init_via() failed\n");
221 	via = NULL;
222 	return 0;
223     }
224 
225     /* enable autopoll */
226     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
227     while (!req.complete)
228 	cuda_poll();
229 
230     return 1;
231 }
232 #else
233 int __init find_via_cuda(void)
234 {
235     struct adb_request req;
236     phys_addr_t taddr;
237     const u32 *reg;
238     int err;
239 
240     if (vias != 0)
241 	return 1;
242     vias = of_find_node_by_name(NULL, "via-cuda");
243     if (vias == 0)
244 	return 0;
245 
246     reg = of_get_property(vias, "reg", NULL);
247     if (reg == NULL) {
248 	    printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
249 	    goto fail;
250     }
251     taddr = of_translate_address(vias, reg);
252     if (taddr == 0) {
253 	    printk(KERN_ERR "via-cuda: Can't translate address !\n");
254 	    goto fail;
255     }
256     via = ioremap(taddr, 0x2000);
257     if (via == NULL) {
258 	    printk(KERN_ERR "via-cuda: Can't map address !\n");
259 	    goto fail;
260     }
261 
262     cuda_state = idle;
263     sys_ctrler = SYS_CTRLER_CUDA;
264 
265     err = cuda_init_via();
266     if (err) {
267 	printk(KERN_ERR "cuda_init_via() failed\n");
268 	via = NULL;
269 	return 0;
270     }
271 
272     /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
273     /* for us by the main VIA driver in arch/m68k/mac/via.c        */
274 
275     out_8(&via[IFR], 0x7f);	/* clear interrupts by writing 1s */
276     out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
277 
278     /* enable autopoll */
279     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
280     while (!req.complete)
281 	cuda_poll();
282 
283     return 1;
284 
285  fail:
286     of_node_put(vias);
287     vias = NULL;
288     return 0;
289 }
290 #endif /* !defined CONFIG_MAC */
291 
292 static int __init via_cuda_start(void)
293 {
294     if (via == NULL)
295 	return -ENODEV;
296 
297 #ifdef CONFIG_MAC
298     cuda_irq = IRQ_MAC_ADB;
299 #else
300     cuda_irq = irq_of_parse_and_map(vias, 0);
301     if (!cuda_irq) {
302 	printk(KERN_ERR "via-cuda: can't map interrupts for %pOF\n",
303 	       vias);
304 	return -ENODEV;
305     }
306 #endif
307 
308     if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
309 	printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
310 	return -EAGAIN;
311     }
312 
313     pr_info("Macintosh Cuda and Egret driver.\n");
314 
315     cuda_fully_inited = 1;
316     return 0;
317 }
318 
319 device_initcall(via_cuda_start);
320 
321 #ifdef CONFIG_ADB
322 static int
323 cuda_probe(void)
324 {
325 #ifdef CONFIG_PPC
326     if (sys_ctrler != SYS_CTRLER_CUDA)
327 	return -ENODEV;
328 #else
329     if (macintosh_config->adb_type != MAC_ADB_CUDA &&
330         macintosh_config->adb_type != MAC_ADB_EGRET)
331 	return -ENODEV;
332 #endif
333     if (via == NULL)
334 	return -ENODEV;
335     return 0;
336 }
337 #endif /* CONFIG_ADB */
338 
339 static int __init sync_egret(void)
340 {
341 	if (TREQ_asserted(in_8(&via[B]))) {
342 		/* Complete the inbound transfer */
343 		assert_TIP_and_TACK();
344 		while (1) {
345 			negate_TACK();
346 			mdelay(1);
347 			(void)in_8(&via[SR]);
348 			assert_TACK();
349 			if (!TREQ_asserted(in_8(&via[B])))
350 				break;
351 		}
352 		negate_TIP_and_TACK();
353 	} else if (in_8(&via[B]) & TIP) {
354 		/* Terminate the outbound transfer */
355 		negate_TACK();
356 		assert_TACK();
357 		mdelay(1);
358 		negate_TIP_and_TACK();
359 	}
360 	/* Clear shift register interrupt */
361 	if (in_8(&via[IFR]) & SR_INT)
362 		(void)in_8(&via[SR]);
363 	return 0;
364 }
365 
366 #define WAIT_FOR(cond, what)					\
367     do {                                                        \
368     	int x;							\
369 	for (x = 1000; !(cond); --x) {				\
370 	    if (x == 0) {					\
371 		pr_err("Timeout waiting for " what "\n");	\
372 		return -ENXIO;					\
373 	    }							\
374 	    udelay(100);					\
375 	}							\
376     } while (0)
377 
378 static int
379 __init cuda_init_via(void)
380 {
381 #ifdef CONFIG_PPC
382     out_8(&via[IER], 0x7f);					/* disable interrupts from VIA */
383     (void)in_8(&via[IER]);
384 #else
385     out_8(&via[IER], SR_INT);					/* disable SR interrupt from VIA */
386 #endif
387 
388     out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ);	/* TACK & TIP out */
389     out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);	/* SR data in */
390     (void)in_8(&via[SR]);					/* clear any left-over data */
391 
392     if (mcu_is_egret)
393 	return sync_egret();
394 
395     negate_TIP_and_TACK();
396 
397     /* delay 4ms and then clear any pending interrupt */
398     mdelay(4);
399     (void)in_8(&via[SR]);
400     out_8(&via[IFR], SR_INT);
401 
402     /* sync with the CUDA - assert TACK without TIP */
403     assert_TACK();
404 
405     /* wait for the CUDA to assert TREQ in response */
406     WAIT_FOR(TREQ_asserted(in_8(&via[B])), "CUDA response to sync");
407 
408     /* wait for the interrupt and then clear it */
409     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
410     (void)in_8(&via[SR]);
411     out_8(&via[IFR], SR_INT);
412 
413     /* finish the sync by negating TACK */
414     negate_TACK();
415 
416     /* wait for the CUDA to negate TREQ and the corresponding interrupt */
417     WAIT_FOR(!TREQ_asserted(in_8(&via[B])), "CUDA response to sync (3)");
418     WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
419     (void)in_8(&via[SR]);
420     out_8(&via[IFR], SR_INT);
421 
422     return 0;
423 }
424 
425 #ifdef CONFIG_ADB
426 /* Send an ADB command */
427 static int
428 cuda_send_request(struct adb_request *req, int sync)
429 {
430     int i;
431 
432     if ((via == NULL) || !cuda_fully_inited) {
433 	req->complete = 1;
434 	return -ENXIO;
435     }
436 
437     req->reply_expected = 1;
438 
439     i = cuda_write(req);
440     if (i)
441 	return i;
442 
443     if (sync) {
444 	while (!req->complete)
445 	    cuda_poll();
446     }
447     return 0;
448 }
449 
450 
451 /* Enable/disable autopolling */
452 static int
453 cuda_adb_autopoll(int devs)
454 {
455     struct adb_request req;
456 
457     if ((via == NULL) || !cuda_fully_inited)
458 	return -ENXIO;
459 
460     cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
461     while (!req.complete)
462 	cuda_poll();
463     return 0;
464 }
465 
466 /* Reset adb bus - how do we do this?? */
467 static int
468 cuda_reset_adb_bus(void)
469 {
470     struct adb_request req;
471 
472     if ((via == NULL) || !cuda_fully_inited)
473 	return -ENXIO;
474 
475     cuda_request(&req, NULL, 2, ADB_PACKET, 0);		/* maybe? */
476     while (!req.complete)
477 	cuda_poll();
478     return 0;
479 }
480 #endif /* CONFIG_ADB */
481 
482 /* Construct and send a cuda request */
483 int
484 cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
485 	     int nbytes, ...)
486 {
487     va_list list;
488     int i;
489 
490     if (via == NULL) {
491 	req->complete = 1;
492 	return -ENXIO;
493     }
494 
495     req->nbytes = nbytes;
496     req->done = done;
497     va_start(list, nbytes);
498     for (i = 0; i < nbytes; ++i)
499 	req->data[i] = va_arg(list, int);
500     va_end(list);
501     req->reply_expected = 1;
502     return cuda_write(req);
503 }
504 EXPORT_SYMBOL(cuda_request);
505 
506 static int
507 cuda_write(struct adb_request *req)
508 {
509     unsigned long flags;
510 
511     if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
512 	req->complete = 1;
513 	return -EINVAL;
514     }
515     req->next = NULL;
516     req->sent = 0;
517     req->complete = 0;
518     req->reply_len = 0;
519 
520     spin_lock_irqsave(&cuda_lock, flags);
521     if (current_req != 0) {
522 	last_req->next = req;
523 	last_req = req;
524     } else {
525 	current_req = req;
526 	last_req = req;
527 	if (cuda_state == idle)
528 	    cuda_start();
529     }
530     spin_unlock_irqrestore(&cuda_lock, flags);
531 
532     return 0;
533 }
534 
535 static void
536 cuda_start(void)
537 {
538     /* assert cuda_state == idle */
539     if (current_req == NULL)
540 	return;
541     data_index = 0;
542     if (TREQ_asserted(in_8(&via[B])))
543 	return;			/* a byte is coming in from the CUDA */
544 
545     /* set the shift register to shift out and send a byte */
546     out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
547     out_8(&via[SR], current_req->data[data_index++]);
548     if (mcu_is_egret)
549 	assert_TIP_and_TACK();
550     else
551 	assert_TIP();
552     cuda_state = sent_first_byte;
553 }
554 
555 void
556 cuda_poll(void)
557 {
558 	cuda_interrupt(0, NULL);
559 }
560 EXPORT_SYMBOL(cuda_poll);
561 
562 #define ARRAY_FULL(a, p)	((p) - (a) == ARRAY_SIZE(a))
563 
564 static irqreturn_t
565 cuda_interrupt(int irq, void *arg)
566 {
567     unsigned long flags;
568     u8 status;
569     struct adb_request *req = NULL;
570     unsigned char ibuf[16];
571     int ibuf_len = 0;
572     int complete = 0;
573     bool full;
574 
575     spin_lock_irqsave(&cuda_lock, flags);
576 
577     /* On powermacs, this handler is registered for the VIA IRQ. But they use
578      * just the shift register IRQ -- other VIA interrupt sources are disabled.
579      * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
580      * we are polling, the shift register IRQ flag has already been cleared.
581      */
582 
583 #ifdef CONFIG_MAC
584     if (!arg)
585 #endif
586     {
587         if ((in_8(&via[IFR]) & SR_INT) == 0) {
588             spin_unlock_irqrestore(&cuda_lock, flags);
589             return IRQ_NONE;
590         } else {
591             out_8(&via[IFR], SR_INT);
592         }
593     }
594 
595     status = in_8(&via[B]) & (TIP | TACK | TREQ);
596 
597     switch (cuda_state) {
598     case idle:
599 	/* System controller has unsolicited data for us */
600 	(void)in_8(&via[SR]);
601 idle_state:
602 	assert_TIP();
603 	cuda_state = reading;
604 	reply_ptr = cuda_rbuf;
605 	reading_reply = 0;
606 	break;
607 
608     case awaiting_reply:
609 	/* System controller has reply data for us */
610 	(void)in_8(&via[SR]);
611 	assert_TIP();
612 	cuda_state = reading;
613 	reply_ptr = current_req->reply;
614 	reading_reply = 1;
615 	break;
616 
617     case sent_first_byte:
618 	if (TREQ_asserted(status)) {
619 	    /* collision */
620 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
621 	    (void)in_8(&via[SR]);
622 	    negate_TIP_and_TACK();
623 	    cuda_state = idle;
624 	    /* Egret does not raise an "aborted" interrupt */
625 	    if (mcu_is_egret)
626 		goto idle_state;
627 	} else {
628 	    out_8(&via[SR], current_req->data[data_index++]);
629 	    toggle_TACK();
630 	    if (mcu_is_egret)
631 		assert_TACK();
632 	    cuda_state = sending;
633 	}
634 	break;
635 
636     case sending:
637 	req = current_req;
638 	if (data_index >= req->nbytes) {
639 	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
640 	    (void)in_8(&via[SR]);
641 	    negate_TIP_and_TACK();
642 	    req->sent = 1;
643 	    if (req->reply_expected) {
644 		cuda_state = awaiting_reply;
645 	    } else {
646 		current_req = req->next;
647 		complete = 1;
648 		/* not sure about this */
649 		cuda_state = idle;
650 		cuda_start();
651 	    }
652 	} else {
653 	    out_8(&via[SR], req->data[data_index++]);
654 	    toggle_TACK();
655 	    if (mcu_is_egret)
656 		assert_TACK();
657 	}
658 	break;
659 
660     case reading:
661 	full = reading_reply ? ARRAY_FULL(current_req->reply, reply_ptr)
662 	                     : ARRAY_FULL(cuda_rbuf, reply_ptr);
663 	if (full)
664 	    (void)in_8(&via[SR]);
665 	else
666 	    *reply_ptr++ = in_8(&via[SR]);
667 	if (!TREQ_asserted(status) || full) {
668 	    if (mcu_is_egret)
669 		assert_TACK();
670 	    /* that's all folks */
671 	    negate_TIP_and_TACK();
672 	    cuda_state = read_done;
673 	    /* Egret does not raise a "read done" interrupt */
674 	    if (mcu_is_egret)
675 		goto read_done_state;
676 	} else {
677 	    toggle_TACK();
678 	    if (mcu_is_egret)
679 		negate_TACK();
680 	}
681 	break;
682 
683     case read_done:
684 	(void)in_8(&via[SR]);
685 read_done_state:
686 	if (reading_reply) {
687 	    req = current_req;
688 	    req->reply_len = reply_ptr - req->reply;
689 	    if (req->data[0] == ADB_PACKET) {
690 		/* Have to adjust the reply from ADB commands */
691 		if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
692 		    /* the 0x2 bit indicates no response */
693 		    req->reply_len = 0;
694 		} else {
695 		    /* leave just the command and result bytes in the reply */
696 		    req->reply_len -= 2;
697 		    memmove(req->reply, req->reply + 2, req->reply_len);
698 		}
699 	    }
700 	    current_req = req->next;
701 	    complete = 1;
702 	    reading_reply = 0;
703 	} else {
704 	    /* This is tricky. We must break the spinlock to call
705 	     * cuda_input. However, doing so means we might get
706 	     * re-entered from another CPU getting an interrupt
707 	     * or calling cuda_poll(). I ended up using the stack
708 	     * (it's only for 16 bytes) and moving the actual
709 	     * call to cuda_input to outside of the lock.
710 	     */
711 	    ibuf_len = reply_ptr - cuda_rbuf;
712 	    memcpy(ibuf, cuda_rbuf, ibuf_len);
713 	}
714 	reply_ptr = cuda_rbuf;
715 	cuda_state = idle;
716 	cuda_start();
717 	if (cuda_state == idle && TREQ_asserted(in_8(&via[B]))) {
718 	    assert_TIP();
719 	    cuda_state = reading;
720 	}
721 	break;
722 
723     default:
724 	pr_err("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
725     }
726     spin_unlock_irqrestore(&cuda_lock, flags);
727     if (complete && req) {
728     	void (*done)(struct adb_request *) = req->done;
729     	mb();
730     	req->complete = 1;
731     	/* Here, we assume that if the request has a done member, the
732     	 * struct request will survive to setting req->complete to 1
733     	 */
734     	if (done)
735 		(*done)(req);
736     }
737     if (ibuf_len)
738 	cuda_input(ibuf, ibuf_len);
739     return IRQ_HANDLED;
740 }
741 
742 static void
743 cuda_input(unsigned char *buf, int nb)
744 {
745     switch (buf[0]) {
746     case ADB_PACKET:
747 #ifdef CONFIG_XMON
748 	if (nb == 5 && buf[2] == 0x2c) {
749 	    extern int xmon_wants_key, xmon_adb_keycode;
750 	    if (xmon_wants_key) {
751 		xmon_adb_keycode = buf[3];
752 		return;
753 	    }
754 	}
755 #endif /* CONFIG_XMON */
756 #ifdef CONFIG_ADB
757 	adb_input(buf+2, nb-2, buf[1] & 0x40);
758 #endif /* CONFIG_ADB */
759 	break;
760 
761     case TIMER_PACKET:
762 	/* Egret sends these periodically. Might be useful as a 'heartbeat'
763 	 * to trigger a recovery for the VIA shift register errata.
764 	 */
765 	break;
766 
767     default:
768 	print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1,
769 	               buf, nb, false);
770     }
771 }
772 
773 /* Offset between Unix time (1970-based) and Mac time (1904-based) */
774 #define RTC_OFFSET	2082844800
775 
776 time64_t cuda_get_time(void)
777 {
778 	struct adb_request req;
779 	u32 now;
780 
781 	if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
782 		return 0;
783 	while (!req.complete)
784 		cuda_poll();
785 	if (req.reply_len != 7)
786 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
787 	now = (req.reply[3] << 24) + (req.reply[4] << 16) +
788 	      (req.reply[5] << 8) + req.reply[6];
789 	return (time64_t)now - RTC_OFFSET;
790 }
791 
792 int cuda_set_rtc_time(struct rtc_time *tm)
793 {
794 	u32 now;
795 	struct adb_request req;
796 
797 	now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
798 	if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
799 	                 now >> 24, now >> 16, now >> 8, now) < 0)
800 		return -ENXIO;
801 	while (!req.complete)
802 		cuda_poll();
803 	if ((req.reply_len != 3) && (req.reply_len != 7))
804 		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
805 	return 0;
806 }
807