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v5.4
  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 <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
 32static volatile unsigned char __iomem *via;
 33static 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
 96static bool mcu_is_egret;
 97#endif
 98
 99static inline bool TREQ_asserted(u8 portb)
100{
101	return !(portb & TREQ);
102}
103
104static 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
113static 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
122static 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
131static inline void toggle_TACK(void)
132{
133	out_8(&via[B], in_8(&via[B]) ^ TACK);
134}
135
136static 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
145static 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
154static enum cuda_state {
155    idle,
156    sent_first_byte,
157    sending,
158    reading,
159    read_done,
160    awaiting_reply
161} cuda_state;
162
163static struct adb_request *current_req;
164static struct adb_request *last_req;
165static unsigned char cuda_rbuf[16];
166static unsigned char *reply_ptr;
167static int reading_reply;
168static int data_index;
169static int cuda_irq;
170#ifdef CONFIG_PPC
171static struct device_node *vias;
172#endif
173static int cuda_fully_inited;
174
175#ifdef CONFIG_ADB
176static int cuda_probe(void);
177static int cuda_send_request(struct adb_request *req, int sync);
178static int cuda_adb_autopoll(int devs);
179static int cuda_reset_adb_bus(void);
180#endif /* CONFIG_ADB */
181
182static int cuda_init_via(void);
183static void cuda_start(void);
184static irqreturn_t cuda_interrupt(int irq, void *arg);
185static void cuda_input(unsigned char *buf, int nb);
186void cuda_poll(void);
187static int cuda_write(struct adb_request *req);
188
189int cuda_request(struct adb_request *req,
190		 void (*done)(struct adb_request *), int nbytes, ...);
191
192#ifdef CONFIG_ADB
193struct 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
204int __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
232int __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
291static 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
318device_initcall(via_cuda_start);
319
320#ifdef CONFIG_ADB
321static int
322cuda_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
338static 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
377static 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 */
426static int
427cuda_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 */
451static int
452cuda_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?? */
466static int
467cuda_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 */
482int
483cuda_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}
503EXPORT_SYMBOL(cuda_request);
504
505static int
506cuda_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
534static void
535cuda_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
554void
555cuda_poll(void)
556{
557	cuda_interrupt(0, NULL);
558}
559EXPORT_SYMBOL(cuda_poll);
560
561#define ARRAY_FULL(a, p)	((p) - (a) == ARRAY_SIZE(a))
562
563static irqreturn_t
564cuda_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]);
600idle_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]);
684read_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
741static void
742cuda_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
775time64_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
791int 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}
v6.2
  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
 35static volatile unsigned char __iomem *via;
 36static 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
 99static bool mcu_is_egret;
100#endif
101
102static inline bool TREQ_asserted(u8 portb)
103{
104	return !(portb & TREQ);
105}
106
107static 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
116static 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
125static 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
134static inline void toggle_TACK(void)
135{
136	out_8(&via[B], in_8(&via[B]) ^ TACK);
137}
138
139static 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
148static 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
157static enum cuda_state {
158    idle,
159    sent_first_byte,
160    sending,
161    reading,
162    read_done,
163    awaiting_reply
164} cuda_state;
165
166static struct adb_request *current_req;
167static struct adb_request *last_req;
168static unsigned char cuda_rbuf[16];
169static unsigned char *reply_ptr;
170static int reading_reply;
171static int data_index;
172static int cuda_irq;
173#ifdef CONFIG_PPC
174static struct device_node *vias;
175#endif
176static int cuda_fully_inited;
177
178#ifdef CONFIG_ADB
179static int cuda_probe(void);
180static int cuda_send_request(struct adb_request *req, int sync);
181static int cuda_adb_autopoll(int devs);
182static int cuda_reset_adb_bus(void);
183#endif /* CONFIG_ADB */
184
185static int cuda_init_via(void);
186static void cuda_start(void);
187static irqreturn_t cuda_interrupt(int irq, void *arg);
188static void cuda_input(unsigned char *buf, int nb);
189void cuda_poll(void);
190static int cuda_write(struct adb_request *req);
191
192int cuda_request(struct adb_request *req,
193		 void (*done)(struct adb_request *), int nbytes, ...);
194
195#ifdef CONFIG_ADB
196struct 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
207int __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
235int __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
294static 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
321device_initcall(via_cuda_start);
322
323#ifdef CONFIG_ADB
324static int
325cuda_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
341static 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
380static 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 */
429static int
430cuda_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 */
454static int
455cuda_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?? */
469static int
470cuda_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 */
485int
486cuda_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}
506EXPORT_SYMBOL(cuda_request);
507
508static int
509cuda_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
537static void
538cuda_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
557void
558cuda_poll(void)
559{
560	cuda_interrupt(0, NULL);
561}
562EXPORT_SYMBOL(cuda_poll);
563
564#define ARRAY_FULL(a, p)	((p) - (a) == ARRAY_SIZE(a))
565
566static irqreturn_t
567cuda_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]);
603idle_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]);
687read_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
744static void
745cuda_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
778time64_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
794int 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}