1/*
2 * Device driver for the via-cuda on Apple Powermacs.
3 *
4 * The VIA (versatile interface adapter) interfaces to the CUDA,
5 * a 6805 microprocessor core which controls the ADB (Apple Desktop
6 * Bus) which connects to the keyboard and mouse.  The CUDA also
7 * controls system power and the RTC (real time clock) chip.
8 *
9 * Copyright (C) 1996 Paul Mackerras.
10 */
11#include <stdarg.h>
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/kernel.h>
15#include <linux/delay.h>
16#include <linux/adb.h>
17#include <linux/cuda.h>
18#include <linux/spinlock.h>
19#include <linux/interrupt.h>
20#ifdef CONFIG_PPC
21#include <asm/prom.h>
22#include <asm/machdep.h>
23#else
24#include <asm/macintosh.h>
25#include <asm/macints.h>
26#include <asm/machw.h>
27#include <asm/mac_via.h>
28#endif
29#include <asm/io.h>
30#include <asm/system.h>
31#include <linux/init.h>
32
33static volatile unsigned char __iomem *via;
34static 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/* Bits in B data register: all active low */
56#define TREQ		0x08		/* Transfer request (input) */
57#define TACK		0x10		/* Transfer acknowledge (output) */
58#define TIP		0x20		/* Transfer in progress (output) */
59
60/* Bits in ACR */
61#define SR_CTRL		0x1c		/* Shift register control bits */
62#define SR_EXT		0x0c		/* Shift on external clock */
63#define SR_OUT		0x10		/* Shift out if 1 */
64
65/* Bits in IFR and IER */
66#define IER_SET		0x80		/* set bits in IER */
67#define IER_CLR		0		/* clear bits in IER */
68#define SR_INT		0x04		/* Shift register full/empty */
69
70static enum cuda_state {
71    idle,
72    sent_first_byte,
73    sending,
74    reading,
75    read_done,
76    awaiting_reply
77} cuda_state;
78
79static struct adb_request *current_req;
80static struct adb_request *last_req;
81static unsigned char cuda_rbuf[16];
82static unsigned char *reply_ptr;
83static int reading_reply;
84static int data_index;
85static int cuda_irq;
86#ifdef CONFIG_PPC
87static struct device_node *vias;
88#endif
89static int cuda_fully_inited;
90
91#ifdef CONFIG_ADB
92static int cuda_probe(void);
93static int cuda_init(void);
94static int cuda_send_request(struct adb_request *req, int sync);
95static int cuda_adb_autopoll(int devs);
96static int cuda_reset_adb_bus(void);
97#endif /* CONFIG_ADB */
98
99static int cuda_init_via(void);
100static void cuda_start(void);
101static irqreturn_t cuda_interrupt(int irq, void *arg);
102static void cuda_input(unsigned char *buf, int nb);
103void cuda_poll(void);
104static int cuda_write(struct adb_request *req);
105
106int cuda_request(struct adb_request *req,
107		 void (*done)(struct adb_request *), int nbytes, ...);
108
109#ifdef CONFIG_ADB
110struct adb_driver via_cuda_driver = {
111	"CUDA",
112	cuda_probe,
113	cuda_init,
114	cuda_send_request,
115	cuda_adb_autopoll,
116	cuda_poll,
117	cuda_reset_adb_bus
118};
119#endif /* CONFIG_ADB */
120
121#ifdef CONFIG_PPC
122int __init find_via_cuda(void)
123{
124    struct adb_request req;
125    phys_addr_t taddr;
126    const u32 *reg;
127    int err;
128
129    if (vias != 0)
130	return 1;
131    vias = of_find_node_by_name(NULL, "via-cuda");
132    if (vias == 0)
133	return 0;
134
135    reg = of_get_property(vias, "reg", NULL);
136    if (reg == NULL) {
137	    printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
138	    goto fail;
139    }
140    taddr = of_translate_address(vias, reg);
141    if (taddr == 0) {
142	    printk(KERN_ERR "via-cuda: Can't translate address !\n");
143	    goto fail;
144    }
145    via = ioremap(taddr, 0x2000);
146    if (via == NULL) {
147	    printk(KERN_ERR "via-cuda: Can't map address !\n");
148	    goto fail;
149    }
150
151    cuda_state = idle;
152    sys_ctrler = SYS_CTRLER_CUDA;
153
154    err = cuda_init_via();
155    if (err) {
156	printk(KERN_ERR "cuda_init_via() failed\n");
157	via = NULL;
158	return 0;
159    }
160
161    /* Clear and enable interrupts, but only on PPC. On 68K it's done  */
162    /* for us by the main VIA driver in arch/m68k/mac/via.c        */
163
164    out_8(&via[IFR], 0x7f);	/* clear interrupts by writing 1s */
165    out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
166
167    /* enable autopoll */
168    cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
169    while (!req.complete)
170	cuda_poll();
171
172    return 1;
173
174 fail:
175    of_node_put(vias);
176    vias = NULL;
177    return 0;
178}
179#endif /* CONFIG_PPC */
180
181static int __init via_cuda_start(void)
182{
183    if (via == NULL)
184	return -ENODEV;
185
186#ifdef CONFIG_MAC
187    cuda_irq = IRQ_MAC_ADB;
188#else /* CONFIG_MAC */
189    cuda_irq = irq_of_parse_and_map(vias, 0);
190    if (cuda_irq == NO_IRQ) {
191	printk(KERN_ERR "via-cuda: can't map interrupts for %s\n",
192	       vias->full_name);
193	return -ENODEV;
194    }
195#endif /* CONFIG_MAC */
196
197    if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
198	printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
199	return -EAGAIN;
200    }
201
202    printk("Macintosh CUDA driver v0.5 for Unified ADB.\n");
203
204    cuda_fully_inited = 1;
205    return 0;
206}
207
208device_initcall(via_cuda_start);
209
210#ifdef CONFIG_ADB
211static int
212cuda_probe(void)
213{
214#ifdef CONFIG_PPC
215    if (sys_ctrler != SYS_CTRLER_CUDA)
216	return -ENODEV;
217#else
218    if (macintosh_config->adb_type != MAC_ADB_CUDA)
219	return -ENODEV;
220    via = via1;
221#endif
222    return 0;
223}
224
225static int __init
226cuda_init(void)
227{
228#ifdef CONFIG_PPC
229    if (via == NULL)
230	return -ENODEV;
231    return 0;
232#else
233    int err = cuda_init_via();
234    if (err) {
235	printk(KERN_ERR "cuda_init_via() failed\n");
236	return -ENODEV;
237    }
238    out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
239
240    return via_cuda_start();
241#endif
242}
243#endif /* CONFIG_ADB */
244
245#define WAIT_FOR(cond, what)					\
246    do {                                                        \
247    	int x;							\
248	for (x = 1000; !(cond); --x) {				\
249	    if (x == 0) {					\
250		printk("Timeout waiting for " what "\n");	\
251		return -ENXIO;					\
252	    }							\
253	    udelay(100);					\
254	}							\
255    } while (0)
256
257static int
258cuda_init_via(void)
259{
260    out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ);	/* TACK & TIP out */
261    out_8(&via[B], in_8(&via[B]) | TACK | TIP);			/* negate them */
262    out_8(&via[ACR] ,(in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT);	/* SR data in */
263    (void)in_8(&via[SR]);						/* clear any left-over data */
264#ifdef CONFIG_PPC
265    out_8(&via[IER], 0x7f);					/* disable interrupts from VIA */
266    (void)in_8(&via[IER]);
267#else
268    out_8(&via[IER], SR_INT);					/* disable SR interrupt from VIA */
269#endif
270
271    /* delay 4ms and then clear any pending interrupt */
272    mdelay(4);
273    (void)in_8(&via[SR]);
274    out_8(&via[IFR], SR_INT);
275
276    /* sync with the CUDA - assert TACK without TIP */
277    out_8(&via[B], in_8(&via[B]) & ~TACK);
278
279    /* wait for the CUDA to assert TREQ in response */
280    WAIT_FOR((in_8(&via[B]) & TREQ) == 0, "CUDA response to sync");
281
282    /* wait for the interrupt and then clear it */
283    WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
284    (void)in_8(&via[SR]);
285    out_8(&via[IFR], SR_INT);
286
287    /* finish the sync by negating TACK */
288    out_8(&via[B], in_8(&via[B]) | TACK);
289
290    /* wait for the CUDA to negate TREQ and the corresponding interrupt */
291    WAIT_FOR(in_8(&via[B]) & TREQ, "CUDA response to sync (3)");
292    WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
293    (void)in_8(&via[SR]);
294    out_8(&via[IFR], SR_INT);
295    out_8(&via[B], in_8(&via[B]) | TIP);	/* should be unnecessary */
296
297    return 0;
298}
299
300#ifdef CONFIG_ADB
301/* Send an ADB command */
302static int
303cuda_send_request(struct adb_request *req, int sync)
304{
305    int i;
306
307    if ((via == NULL) || !cuda_fully_inited) {
308	req->complete = 1;
309	return -ENXIO;
310    }
311
312    req->reply_expected = 1;
313
314    i = cuda_write(req);
315    if (i)
316	return i;
317
318    if (sync) {
319	while (!req->complete)
320	    cuda_poll();
321    }
322    return 0;
323}
324
325
326/* Enable/disable autopolling */
327static int
328cuda_adb_autopoll(int devs)
329{
330    struct adb_request req;
331
332    if ((via == NULL) || !cuda_fully_inited)
333	return -ENXIO;
334
335    cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
336    while (!req.complete)
337	cuda_poll();
338    return 0;
339}
340
341/* Reset adb bus - how do we do this?? */
342static int
343cuda_reset_adb_bus(void)
344{
345    struct adb_request req;
346
347    if ((via == NULL) || !cuda_fully_inited)
348	return -ENXIO;
349
350    cuda_request(&req, NULL, 2, ADB_PACKET, 0);		/* maybe? */
351    while (!req.complete)
352	cuda_poll();
353    return 0;
354}
355#endif /* CONFIG_ADB */
356/* Construct and send a cuda request */
357int
358cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
359	     int nbytes, ...)
360{
361    va_list list;
362    int i;
363
364    if (via == NULL) {
365	req->complete = 1;
366	return -ENXIO;
367    }
368
369    req->nbytes = nbytes;
370    req->done = done;
371    va_start(list, nbytes);
372    for (i = 0; i < nbytes; ++i)
373	req->data[i] = va_arg(list, int);
374    va_end(list);
375    req->reply_expected = 1;
376    return cuda_write(req);
377}
378
379static int
380cuda_write(struct adb_request *req)
381{
382    unsigned long flags;
383
384    if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
385	req->complete = 1;
386	return -EINVAL;
387    }
388    req->next = NULL;
389    req->sent = 0;
390    req->complete = 0;
391    req->reply_len = 0;
392
393    spin_lock_irqsave(&cuda_lock, flags);
394    if (current_req != 0) {
395	last_req->next = req;
396	last_req = req;
397    } else {
398	current_req = req;
399	last_req = req;
400	if (cuda_state == idle)
401	    cuda_start();
402    }
403    spin_unlock_irqrestore(&cuda_lock, flags);
404
405    return 0;
406}
407
408static void
409cuda_start(void)
410{
411    struct adb_request *req;
412
413    /* assert cuda_state == idle */
414    /* get the packet to send */
415    req = current_req;
416    if (req == 0)
417	return;
418    if ((in_8(&via[B]) & TREQ) == 0)
419	return;			/* a byte is coming in from the CUDA */
420
421    /* set the shift register to shift out and send a byte */
422    out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
423    out_8(&via[SR], req->data[0]);
424    out_8(&via[B], in_8(&via[B]) & ~TIP);
425    cuda_state = sent_first_byte;
426}
427
428void
429cuda_poll(void)
430{
431    /* cuda_interrupt only takes a normal lock, we disable
432     * interrupts here to avoid re-entering and thus deadlocking.
433     */
434    disable_irq(cuda_irq);
435    cuda_interrupt(0, NULL);
436    enable_irq(cuda_irq);
437}
438
439static irqreturn_t
440cuda_interrupt(int irq, void *arg)
441{
442    int status;
443    struct adb_request *req = NULL;
444    unsigned char ibuf[16];
445    int ibuf_len = 0;
446    int complete = 0;
447
448    spin_lock(&cuda_lock);
449
450    /* On powermacs, this handler is registered for the VIA IRQ. But it uses
451     * just the shift register IRQ -- other VIA interrupt sources are disabled.
452     * On m68k macs, the VIA IRQ sources are dispatched individually. Unless
453     * we are polling, the shift register IRQ flag has already been cleared.
454     */
455
456#ifdef CONFIG_MAC
457    if (!arg)
458#endif
459    {
460        if ((in_8(&via[IFR]) & SR_INT) == 0) {
461            spin_unlock(&cuda_lock);
462            return IRQ_NONE;
463        } else {
464            out_8(&via[IFR], SR_INT);
465        }
466    }
467
468    status = (~in_8(&via[B]) & (TIP|TREQ)) | (in_8(&via[ACR]) & SR_OUT);
469    /* printk("cuda_interrupt: state=%d status=%x\n", cuda_state, status); */
470    switch (cuda_state) {
471    case idle:
472	/* CUDA has sent us the first byte of data - unsolicited */
473	if (status != TREQ)
474	    printk("cuda: state=idle, status=%x\n", status);
475	(void)in_8(&via[SR]);
476	out_8(&via[B], in_8(&via[B]) & ~TIP);
477	cuda_state = reading;
478	reply_ptr = cuda_rbuf;
479	reading_reply = 0;
480	break;
481
482    case awaiting_reply:
483	/* CUDA has sent us the first byte of data of a reply */
484	if (status != TREQ)
485	    printk("cuda: state=awaiting_reply, status=%x\n", status);
486	(void)in_8(&via[SR]);
487	out_8(&via[B], in_8(&via[B]) & ~TIP);
488	cuda_state = reading;
489	reply_ptr = current_req->reply;
490	reading_reply = 1;
491	break;
492
493    case sent_first_byte:
494	if (status == TREQ + TIP + SR_OUT) {
495	    /* collision */
496	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
497	    (void)in_8(&via[SR]);
498	    out_8(&via[B], in_8(&via[B]) | TIP | TACK);
499	    cuda_state = idle;
500	} else {
501	    /* assert status == TIP + SR_OUT */
502	    if (status != TIP + SR_OUT)
503		printk("cuda: state=sent_first_byte status=%x\n", status);
504	    out_8(&via[SR], current_req->data[1]);
505	    out_8(&via[B], in_8(&via[B]) ^ TACK);
506	    data_index = 2;
507	    cuda_state = sending;
508	}
509	break;
510
511    case sending:
512	req = current_req;
513	if (data_index >= req->nbytes) {
514	    out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
515	    (void)in_8(&via[SR]);
516	    out_8(&via[B], in_8(&via[B]) | TACK | TIP);
517	    req->sent = 1;
518	    if (req->reply_expected) {
519		cuda_state = awaiting_reply;
520	    } else {
521		current_req = req->next;
522		complete = 1;
523		/* not sure about this */
524		cuda_state = idle;
525		cuda_start();
526	    }
527	} else {
528	    out_8(&via[SR], req->data[data_index++]);
529	    out_8(&via[B], in_8(&via[B]) ^ TACK);
530	}
531	break;
532
533    case reading:
534	*reply_ptr++ = in_8(&via[SR]);
535	if (status == TIP) {
536	    /* that's all folks */
537	    out_8(&via[B], in_8(&via[B]) | TACK | TIP);
538	    cuda_state = read_done;
539	} else {
540	    /* assert status == TIP | TREQ */
541	    if (status != TIP + TREQ)
542		printk("cuda: state=reading status=%x\n", status);
543	    out_8(&via[B], in_8(&via[B]) ^ TACK);
544	}
545	break;
546
547    case read_done:
548	(void)in_8(&via[SR]);
549	if (reading_reply) {
550	    req = current_req;
551	    req->reply_len = reply_ptr - req->reply;
552	    if (req->data[0] == ADB_PACKET) {
553		/* Have to adjust the reply from ADB commands */
554		if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
555		    /* the 0x2 bit indicates no response */
556		    req->reply_len = 0;
557		} else {
558		    /* leave just the command and result bytes in the reply */
559		    req->reply_len -= 2;
560		    memmove(req->reply, req->reply + 2, req->reply_len);
561		}
562	    }
563	    current_req = req->next;
564	    complete = 1;
565	} else {
566	    /* This is tricky. We must break the spinlock to call
567	     * cuda_input. However, doing so means we might get
568	     * re-entered from another CPU getting an interrupt
569	     * or calling cuda_poll(). I ended up using the stack
570	     * (it's only for 16 bytes) and moving the actual
571	     * call to cuda_input to outside of the lock.
572	     */
573	    ibuf_len = reply_ptr - cuda_rbuf;
574	    memcpy(ibuf, cuda_rbuf, ibuf_len);
575	}
576	if (status == TREQ) {
577	    out_8(&via[B], in_8(&via[B]) & ~TIP);
578	    cuda_state = reading;
579	    reply_ptr = cuda_rbuf;
580	    reading_reply = 0;
581	} else {
582	    cuda_state = idle;
583	    cuda_start();
584	}
585	break;
586
587    default:
588	printk("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
589    }
590    spin_unlock(&cuda_lock);
591    if (complete && req) {
592    	void (*done)(struct adb_request *) = req->done;
593    	mb();
594    	req->complete = 1;
595    	/* Here, we assume that if the request has a done member, the
596    	 * struct request will survive to setting req->complete to 1
597    	 */
598    	if (done)
599		(*done)(req);
600    }
601    if (ibuf_len)
602	cuda_input(ibuf, ibuf_len);
603    return IRQ_HANDLED;
604}
605
606static void
607cuda_input(unsigned char *buf, int nb)
608{
609    int i;
610
611    switch (buf[0]) {
612    case ADB_PACKET:
613#ifdef CONFIG_XMON
614	if (nb == 5 && buf[2] == 0x2c) {
615	    extern int xmon_wants_key, xmon_adb_keycode;
616	    if (xmon_wants_key) {
617		xmon_adb_keycode = buf[3];
618		return;
619	    }
620	}
621#endif /* CONFIG_XMON */
622#ifdef CONFIG_ADB
623	adb_input(buf+2, nb-2, buf[1] & 0x40);
624#endif /* CONFIG_ADB */
625	break;
626
627    default:
628	printk("data from cuda (%d bytes):", nb);
629	for (i = 0; i < nb; ++i)
630	    printk(" %.2x", buf[i]);
631	printk("\n");
632    }
633}
634