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1/*
2 * Device driver for the via ADB on (many) Mac II-class machines
3 *
4 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
5 * Also derived from code Copyright (C) 1996 Paul Mackerras.
6 *
7 * With various updates provided over the years by Michael Schmitz,
8 * Guideo Koerber and others.
9 *
10 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
11 *
12 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
13 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
14 * - Big overhaul, should actually work now.
15 * 2006-12-31 Finn Thain <fthain@telegraphics.com.au> - Another overhaul.
16 *
17 * Suggested reading:
18 * Inside Macintosh, ch. 5 ADB Manager
19 * Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus
20 * Rockwell R6522 VIA datasheet
21 *
22 * Apple's "ADB Analyzer" bus sniffer is invaluable:
23 * ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/
24 */
25
26#include <stdarg.h>
27#include <linux/types.h>
28#include <linux/errno.h>
29#include <linux/kernel.h>
30#include <linux/delay.h>
31#include <linux/adb.h>
32#include <linux/interrupt.h>
33#include <linux/init.h>
34#include <asm/macintosh.h>
35#include <asm/macints.h>
36#include <asm/mac_via.h>
37#include <asm/system.h>
38
39static volatile unsigned char *via;
40
41/* VIA registers - spaced 0x200 bytes apart */
42#define RS 0x200 /* skip between registers */
43#define B 0 /* B-side data */
44#define A RS /* A-side data */
45#define DIRB (2*RS) /* B-side direction (1=output) */
46#define DIRA (3*RS) /* A-side direction (1=output) */
47#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
48#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
49#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
50#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
51#define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */
52#define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */
53#define SR (10*RS) /* Shift register */
54#define ACR (11*RS) /* Auxiliary control register */
55#define PCR (12*RS) /* Peripheral control register */
56#define IFR (13*RS) /* Interrupt flag register */
57#define IER (14*RS) /* Interrupt enable register */
58#define ANH (15*RS) /* A-side data, no handshake */
59
60/* Bits in B data register: all active low */
61#define CTLR_IRQ 0x08 /* Controller rcv status (input) */
62#define ST_MASK 0x30 /* mask for selecting ADB state bits */
63
64/* Bits in ACR */
65#define SR_CTRL 0x1c /* Shift register control bits */
66#define SR_EXT 0x0c /* Shift on external clock */
67#define SR_OUT 0x10 /* Shift out if 1 */
68
69/* Bits in IFR and IER */
70#define IER_SET 0x80 /* set bits in IER */
71#define IER_CLR 0 /* clear bits in IER */
72#define SR_INT 0x04 /* Shift register full/empty */
73
74/* ADB transaction states according to GMHW */
75#define ST_CMD 0x00 /* ADB state: command byte */
76#define ST_EVEN 0x10 /* ADB state: even data byte */
77#define ST_ODD 0x20 /* ADB state: odd data byte */
78#define ST_IDLE 0x30 /* ADB state: idle, nothing to send */
79
80static int macii_init_via(void);
81static void macii_start(void);
82static irqreturn_t macii_interrupt(int irq, void *arg);
83static void macii_queue_poll(void);
84
85static int macii_probe(void);
86static int macii_init(void);
87static int macii_send_request(struct adb_request *req, int sync);
88static int macii_write(struct adb_request *req);
89static int macii_autopoll(int devs);
90static void macii_poll(void);
91static int macii_reset_bus(void);
92
93struct adb_driver via_macii_driver = {
94 "Mac II",
95 macii_probe,
96 macii_init,
97 macii_send_request,
98 macii_autopoll,
99 macii_poll,
100 macii_reset_bus
101};
102
103static enum macii_state {
104 idle,
105 sending,
106 reading,
107 read_done,
108} macii_state;
109
110static struct adb_request *current_req; /* first request struct in the queue */
111static struct adb_request *last_req; /* last request struct in the queue */
112static unsigned char reply_buf[16]; /* storage for autopolled replies */
113static unsigned char *reply_ptr; /* next byte in reply_buf or req->reply */
114static int reading_reply; /* store reply in reply_buf else req->reply */
115static int data_index; /* index of the next byte to send from req->data */
116static int reply_len; /* number of bytes received in reply_buf or req->reply */
117static int status; /* VIA's ADB status bits captured upon interrupt */
118static int last_status; /* status bits as at previous interrupt */
119static int srq_asserted; /* have to poll for the device that asserted it */
120static int command_byte; /* the most recent command byte transmitted */
121static int autopoll_devs; /* bits set are device addresses to be polled */
122
123/* Sanity check for request queue. Doesn't check for cycles. */
124static int request_is_queued(struct adb_request *req) {
125 struct adb_request *cur;
126 unsigned long flags;
127 local_irq_save(flags);
128 cur = current_req;
129 while (cur) {
130 if (cur == req) {
131 local_irq_restore(flags);
132 return 1;
133 }
134 cur = cur->next;
135 }
136 local_irq_restore(flags);
137 return 0;
138}
139
140/* Check for MacII style ADB */
141static int macii_probe(void)
142{
143 if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;
144
145 via = via1;
146
147 printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
148 return 0;
149}
150
151/* Initialize the driver */
152int macii_init(void)
153{
154 unsigned long flags;
155 int err;
156
157 local_irq_save(flags);
158
159 err = macii_init_via();
160 if (err) goto out;
161
162 err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
163 macii_interrupt);
164 if (err) goto out;
165
166 macii_state = idle;
167out:
168 local_irq_restore(flags);
169 return err;
170}
171
172/* initialize the hardware */
173static int macii_init_via(void)
174{
175 unsigned char x;
176
177 /* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */
178 via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;
179
180 /* Set up state: idle */
181 via[B] |= ST_IDLE;
182 last_status = via[B] & (ST_MASK|CTLR_IRQ);
183
184 /* Shift register on input */
185 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
186
187 /* Wipe any pending data and int */
188 x = via[SR];
189
190 return 0;
191}
192
193/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
194static void macii_queue_poll(void)
195{
196 /* No point polling the active device as it will never assert SRQ, so
197 * poll the next device in the autopoll list. This could leave us
198 * stuck in a polling loop if an unprobed device is asserting SRQ.
199 * In theory, that could only happen if a device was plugged in after
200 * probing started. Unplugging it again will break the cycle.
201 * (Simply polling the next higher device often ends up polling almost
202 * every device (after wrapping around), which takes too long.)
203 */
204 int device_mask;
205 int next_device;
206 static struct adb_request req;
207
208 if (!autopoll_devs) return;
209
210 device_mask = (1 << (((command_byte & 0xF0) >> 4) + 1)) - 1;
211 if (autopoll_devs & ~device_mask)
212 next_device = ffs(autopoll_devs & ~device_mask) - 1;
213 else
214 next_device = ffs(autopoll_devs) - 1;
215
216 BUG_ON(request_is_queued(&req));
217
218 adb_request(&req, NULL, ADBREQ_NOSEND, 1,
219 ADB_READREG(next_device, 0));
220
221 req.sent = 0;
222 req.complete = 0;
223 req.reply_len = 0;
224 req.next = current_req;
225
226 if (current_req != NULL) {
227 current_req = &req;
228 } else {
229 current_req = &req;
230 last_req = &req;
231 }
232}
233
234/* Send an ADB request; if sync, poll out the reply 'till it's done */
235static int macii_send_request(struct adb_request *req, int sync)
236{
237 int err;
238 unsigned long flags;
239
240 BUG_ON(request_is_queued(req));
241
242 local_irq_save(flags);
243 err = macii_write(req);
244 local_irq_restore(flags);
245
246 if (!err && sync) {
247 while (!req->complete) {
248 macii_poll();
249 }
250 BUG_ON(request_is_queued(req));
251 }
252
253 return err;
254}
255
256/* Send an ADB request (append to request queue) */
257static int macii_write(struct adb_request *req)
258{
259 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
260 req->complete = 1;
261 return -EINVAL;
262 }
263
264 req->next = NULL;
265 req->sent = 0;
266 req->complete = 0;
267 req->reply_len = 0;
268
269 if (current_req != NULL) {
270 last_req->next = req;
271 last_req = req;
272 } else {
273 current_req = req;
274 last_req = req;
275 if (macii_state == idle) macii_start();
276 }
277 return 0;
278}
279
280/* Start auto-polling */
281static int macii_autopoll(int devs)
282{
283 static struct adb_request req;
284 unsigned long flags;
285 int err = 0;
286
287 /* bit 1 == device 1, and so on. */
288 autopoll_devs = devs & 0xFFFE;
289
290 if (!autopoll_devs) return 0;
291
292 local_irq_save(flags);
293
294 if (current_req == NULL) {
295 /* Send a Talk Reg 0. The controller will repeatedly transmit
296 * this as long as it is idle.
297 */
298 adb_request(&req, NULL, ADBREQ_NOSEND, 1,
299 ADB_READREG(ffs(autopoll_devs) - 1, 0));
300 err = macii_write(&req);
301 }
302
303 local_irq_restore(flags);
304 return err;
305}
306
307static inline int need_autopoll(void) {
308 /* Was the last command Talk Reg 0
309 * and is the target on the autopoll list?
310 */
311 if ((command_byte & 0x0F) == 0x0C &&
312 ((1 << ((command_byte & 0xF0) >> 4)) & autopoll_devs))
313 return 0;
314 return 1;
315}
316
317/* Prod the chip without interrupts */
318static void macii_poll(void)
319{
320 disable_irq(IRQ_MAC_ADB);
321 macii_interrupt(0, NULL);
322 enable_irq(IRQ_MAC_ADB);
323}
324
325/* Reset the bus */
326static int macii_reset_bus(void)
327{
328 static struct adb_request req;
329
330 if (request_is_queued(&req))
331 return 0;
332
333 /* Command = 0, Address = ignored */
334 adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
335
336 /* Don't want any more requests during the Global Reset low time. */
337 udelay(3000);
338
339 return 0;
340}
341
342/* Start sending ADB packet */
343static void macii_start(void)
344{
345 struct adb_request *req;
346
347 req = current_req;
348
349 BUG_ON(req == NULL);
350
351 BUG_ON(macii_state != idle);
352
353 /* Now send it. Be careful though, that first byte of the request
354 * is actually ADB_PACKET; the real data begins at index 1!
355 * And req->nbytes is the number of bytes of real data plus one.
356 */
357
358 /* store command byte */
359 command_byte = req->data[1];
360 /* Output mode */
361 via[ACR] |= SR_OUT;
362 /* Load data */
363 via[SR] = req->data[1];
364 /* set ADB state to 'command' */
365 via[B] = (via[B] & ~ST_MASK) | ST_CMD;
366
367 macii_state = sending;
368 data_index = 2;
369}
370
371/*
372 * The notorious ADB interrupt handler - does all of the protocol handling.
373 * Relies on the ADB controller sending and receiving data, thereby
374 * generating shift register interrupts (SR_INT) for us. This means there has
375 * to be activity on the ADB bus. The chip will poll to achieve this.
376 *
377 * The basic ADB state machine was left unchanged from the original MacII code
378 * by Alan Cox, which was based on the CUDA driver for PowerMac.
379 * The syntax of the ADB status lines is totally different on MacII,
380 * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle
381 * for sending and Idle -> Even -> Odd -> Even ->...-> Idle for receiving.
382 * Start and end of a receive packet are signalled by asserting /IRQ on the
383 * interrupt line (/IRQ means the CTLR_IRQ bit in port B; not to be confused
384 * with the VIA shift register interrupt. /IRQ never actually interrupts the
385 * processor, it's just an ordinary input.)
386 */
387static irqreturn_t macii_interrupt(int irq, void *arg)
388{
389 int x;
390 static int entered;
391 struct adb_request *req;
392
393 if (!arg) {
394 /* Clear the SR IRQ flag when polling. */
395 if (via[IFR] & SR_INT)
396 via[IFR] = SR_INT;
397 else
398 return IRQ_NONE;
399 }
400
401 BUG_ON(entered++);
402
403 last_status = status;
404 status = via[B] & (ST_MASK|CTLR_IRQ);
405
406 switch (macii_state) {
407 case idle:
408 if (reading_reply) {
409 reply_ptr = current_req->reply;
410 } else {
411 BUG_ON(current_req != NULL);
412 reply_ptr = reply_buf;
413 }
414
415 x = via[SR];
416
417 if ((status & CTLR_IRQ) && (x == 0xFF)) {
418 /* Bus timeout without SRQ sequence:
419 * data is "FF" while CTLR_IRQ is "H"
420 */
421 reply_len = 0;
422 srq_asserted = 0;
423 macii_state = read_done;
424 } else {
425 macii_state = reading;
426 *reply_ptr = x;
427 reply_len = 1;
428 }
429
430 /* set ADB state = even for first data byte */
431 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
432 break;
433
434 case sending:
435 req = current_req;
436 if (data_index >= req->nbytes) {
437 req->sent = 1;
438 macii_state = idle;
439
440 if (req->reply_expected) {
441 reading_reply = 1;
442 } else {
443 req->complete = 1;
444 current_req = req->next;
445 if (req->done) (*req->done)(req);
446
447 if (current_req)
448 macii_start();
449 else
450 if (need_autopoll())
451 macii_autopoll(autopoll_devs);
452 }
453
454 if (macii_state == idle) {
455 /* reset to shift in */
456 via[ACR] &= ~SR_OUT;
457 x = via[SR];
458 /* set ADB state idle - might get SRQ */
459 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
460 }
461 } else {
462 via[SR] = req->data[data_index++];
463
464 if ( (via[B] & ST_MASK) == ST_CMD ) {
465 /* just sent the command byte, set to EVEN */
466 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
467 } else {
468 /* invert state bits, toggle ODD/EVEN */
469 via[B] ^= ST_MASK;
470 }
471 }
472 break;
473
474 case reading:
475 x = via[SR];
476 BUG_ON((status & ST_MASK) == ST_CMD ||
477 (status & ST_MASK) == ST_IDLE);
478
479 /* Bus timeout with SRQ sequence:
480 * data is "XX FF" while CTLR_IRQ is "L L"
481 * End of packet without SRQ sequence:
482 * data is "XX...YY 00" while CTLR_IRQ is "L...H L"
483 * End of packet SRQ sequence:
484 * data is "XX...YY 00" while CTLR_IRQ is "L...L L"
485 * (where XX is the first response byte and
486 * YY is the last byte of valid response data.)
487 */
488
489 srq_asserted = 0;
490 if (!(status & CTLR_IRQ)) {
491 if (x == 0xFF) {
492 if (!(last_status & CTLR_IRQ)) {
493 macii_state = read_done;
494 reply_len = 0;
495 srq_asserted = 1;
496 }
497 } else if (x == 0x00) {
498 macii_state = read_done;
499 if (!(last_status & CTLR_IRQ))
500 srq_asserted = 1;
501 }
502 }
503
504 if (macii_state == reading) {
505 BUG_ON(reply_len > 15);
506 reply_ptr++;
507 *reply_ptr = x;
508 reply_len++;
509 }
510
511 /* invert state bits, toggle ODD/EVEN */
512 via[B] ^= ST_MASK;
513 break;
514
515 case read_done:
516 x = via[SR];
517
518 if (reading_reply) {
519 reading_reply = 0;
520 req = current_req;
521 req->reply_len = reply_len;
522 req->complete = 1;
523 current_req = req->next;
524 if (req->done) (*req->done)(req);
525 } else if (reply_len && autopoll_devs)
526 adb_input(reply_buf, reply_len, 0);
527
528 macii_state = idle;
529
530 /* SRQ seen before, initiate poll now */
531 if (srq_asserted)
532 macii_queue_poll();
533
534 if (current_req)
535 macii_start();
536 else
537 if (need_autopoll())
538 macii_autopoll(autopoll_devs);
539
540 if (macii_state == idle)
541 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
542 break;
543
544 default:
545 break;
546 }
547
548 entered--;
549 return IRQ_HANDLED;
550}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Device driver for the via ADB on (many) Mac II-class machines
4 *
5 * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
6 * Also derived from code Copyright (C) 1996 Paul Mackerras.
7 *
8 * With various updates provided over the years by Michael Schmitz,
9 * Guideo Koerber and others.
10 *
11 * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
12 *
13 * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
14 * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
15 * - Big overhaul, should actually work now.
16 * 2006-12-31 Finn Thain - Another overhaul.
17 *
18 * Suggested reading:
19 * Inside Macintosh, ch. 5 ADB Manager
20 * Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus
21 * Rockwell R6522 VIA datasheet
22 *
23 * Apple's "ADB Analyzer" bus sniffer is invaluable:
24 * ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/
25 */
26#include <linux/types.h>
27#include <linux/errno.h>
28#include <linux/kernel.h>
29#include <linux/delay.h>
30#include <linux/adb.h>
31#include <linux/interrupt.h>
32#include <linux/init.h>
33#include <asm/macintosh.h>
34#include <asm/macints.h>
35#include <asm/mac_via.h>
36
37static volatile unsigned char *via;
38
39/* VIA registers - spaced 0x200 bytes apart */
40#define RS 0x200 /* skip between registers */
41#define B 0 /* B-side data */
42#define A RS /* A-side data */
43#define DIRB (2*RS) /* B-side direction (1=output) */
44#define DIRA (3*RS) /* A-side direction (1=output) */
45#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
46#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
47#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
48#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
49#define T2CL (8*RS) /* Timer 2 ctr/latch (low 8 bits) */
50#define T2CH (9*RS) /* Timer 2 counter (high 8 bits) */
51#define SR (10*RS) /* Shift register */
52#define ACR (11*RS) /* Auxiliary control register */
53#define PCR (12*RS) /* Peripheral control register */
54#define IFR (13*RS) /* Interrupt flag register */
55#define IER (14*RS) /* Interrupt enable register */
56#define ANH (15*RS) /* A-side data, no handshake */
57
58/* Bits in B data register: all active low */
59#define CTLR_IRQ 0x08 /* Controller rcv status (input) */
60#define ST_MASK 0x30 /* mask for selecting ADB state bits */
61
62/* Bits in ACR */
63#define SR_CTRL 0x1c /* Shift register control bits */
64#define SR_EXT 0x0c /* Shift on external clock */
65#define SR_OUT 0x10 /* Shift out if 1 */
66
67/* Bits in IFR and IER */
68#define IER_SET 0x80 /* set bits in IER */
69#define IER_CLR 0 /* clear bits in IER */
70#define SR_INT 0x04 /* Shift register full/empty */
71
72/* ADB transaction states according to GMHW */
73#define ST_CMD 0x00 /* ADB state: command byte */
74#define ST_EVEN 0x10 /* ADB state: even data byte */
75#define ST_ODD 0x20 /* ADB state: odd data byte */
76#define ST_IDLE 0x30 /* ADB state: idle, nothing to send */
77
78/* ADB command byte structure */
79#define ADDR_MASK 0xF0
80#define CMD_MASK 0x0F
81#define OP_MASK 0x0C
82#define TALK 0x0C
83
84static int macii_init_via(void);
85static void macii_start(void);
86static irqreturn_t macii_interrupt(int irq, void *arg);
87static void macii_queue_poll(void);
88
89static int macii_probe(void);
90static int macii_init(void);
91static int macii_send_request(struct adb_request *req, int sync);
92static int macii_write(struct adb_request *req);
93static int macii_autopoll(int devs);
94static void macii_poll(void);
95static int macii_reset_bus(void);
96
97struct adb_driver via_macii_driver = {
98 .name = "Mac II",
99 .probe = macii_probe,
100 .init = macii_init,
101 .send_request = macii_send_request,
102 .autopoll = macii_autopoll,
103 .poll = macii_poll,
104 .reset_bus = macii_reset_bus,
105};
106
107static enum macii_state {
108 idle,
109 sending,
110 reading,
111} macii_state;
112
113static struct adb_request *current_req; /* first request struct in the queue */
114static struct adb_request *last_req; /* last request struct in the queue */
115static unsigned char reply_buf[16]; /* storage for autopolled replies */
116static unsigned char *reply_ptr; /* next byte in reply_buf or req->reply */
117static bool reading_reply; /* store reply in reply_buf else req->reply */
118static int data_index; /* index of the next byte to send from req->data */
119static int reply_len; /* number of bytes received in reply_buf or req->reply */
120static int status; /* VIA's ADB status bits captured upon interrupt */
121static bool bus_timeout; /* no data was sent by the device */
122static bool srq_asserted; /* have to poll for the device that asserted it */
123static u8 last_cmd; /* the most recent command byte transmitted */
124static u8 last_talk_cmd; /* the most recent Talk command byte transmitted */
125static u8 last_poll_cmd; /* the most recent Talk R0 command byte transmitted */
126static unsigned int autopoll_devs; /* bits set are device addresses to poll */
127
128/* Check for MacII style ADB */
129static int macii_probe(void)
130{
131 if (macintosh_config->adb_type != MAC_ADB_II)
132 return -ENODEV;
133
134 via = via1;
135
136 pr_info("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
137 return 0;
138}
139
140/* Initialize the driver */
141static int macii_init(void)
142{
143 unsigned long flags;
144 int err;
145
146 local_irq_save(flags);
147
148 err = macii_init_via();
149 if (err)
150 goto out;
151
152 err = request_irq(IRQ_MAC_ADB, macii_interrupt, 0, "ADB",
153 macii_interrupt);
154 if (err)
155 goto out;
156
157 macii_state = idle;
158out:
159 local_irq_restore(flags);
160 return err;
161}
162
163/* initialize the hardware */
164static int macii_init_via(void)
165{
166 unsigned char x;
167
168 /* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */
169 via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;
170
171 /* Set up state: idle */
172 via[B] |= ST_IDLE;
173
174 /* Shift register on input */
175 via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
176
177 /* Wipe any pending data and int */
178 x = via[SR];
179
180 return 0;
181}
182
183/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
184static void macii_queue_poll(void)
185{
186 static struct adb_request req;
187 unsigned char poll_command;
188 unsigned int poll_addr;
189
190 /* This only polls devices in the autopoll list, which assumes that
191 * unprobed devices never assert SRQ. That could happen if a device was
192 * plugged in after the adb bus scan. Unplugging it again will resolve
193 * the problem. This behaviour is similar to MacOS.
194 */
195 if (!autopoll_devs)
196 return;
197
198 /* The device most recently polled may not be the best device to poll
199 * right now. Some other device(s) may have signalled SRQ (the active
200 * device won't do that). Or the autopoll list may have been changed.
201 * Try polling the next higher address.
202 */
203 poll_addr = (last_poll_cmd & ADDR_MASK) >> 4;
204 if ((srq_asserted && last_cmd == last_poll_cmd) ||
205 !(autopoll_devs & (1 << poll_addr))) {
206 unsigned int higher_devs;
207
208 higher_devs = autopoll_devs & -(1 << (poll_addr + 1));
209 poll_addr = ffs(higher_devs ? higher_devs : autopoll_devs) - 1;
210 }
211
212 /* Send a Talk Register 0 command */
213 poll_command = ADB_READREG(poll_addr, 0);
214
215 /* No need to repeat this Talk command. The transceiver will do that
216 * as long as it is idle.
217 */
218 if (poll_command == last_cmd)
219 return;
220
221 adb_request(&req, NULL, ADBREQ_NOSEND, 1, poll_command);
222
223 req.sent = 0;
224 req.complete = 0;
225 req.reply_len = 0;
226 req.next = current_req;
227
228 if (WARN_ON(current_req)) {
229 current_req = &req;
230 } else {
231 current_req = &req;
232 last_req = &req;
233 }
234}
235
236/* Send an ADB request; if sync, poll out the reply 'till it's done */
237static int macii_send_request(struct adb_request *req, int sync)
238{
239 int err;
240
241 err = macii_write(req);
242 if (err)
243 return err;
244
245 if (sync)
246 while (!req->complete)
247 macii_poll();
248
249 return 0;
250}
251
252/* Send an ADB request (append to request queue) */
253static int macii_write(struct adb_request *req)
254{
255 unsigned long flags;
256
257 if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
258 req->complete = 1;
259 return -EINVAL;
260 }
261
262 req->next = NULL;
263 req->sent = 0;
264 req->complete = 0;
265 req->reply_len = 0;
266
267 local_irq_save(flags);
268
269 if (current_req != NULL) {
270 last_req->next = req;
271 last_req = req;
272 } else {
273 current_req = req;
274 last_req = req;
275 if (macii_state == idle)
276 macii_start();
277 }
278
279 local_irq_restore(flags);
280
281 return 0;
282}
283
284/* Start auto-polling */
285static int macii_autopoll(int devs)
286{
287 unsigned long flags;
288
289 local_irq_save(flags);
290
291 /* bit 1 == device 1, and so on. */
292 autopoll_devs = (unsigned int)devs & 0xFFFE;
293
294 if (!current_req) {
295 macii_queue_poll();
296 if (current_req && macii_state == idle)
297 macii_start();
298 }
299
300 local_irq_restore(flags);
301
302 return 0;
303}
304
305/* Prod the chip without interrupts */
306static void macii_poll(void)
307{
308 macii_interrupt(0, NULL);
309}
310
311/* Reset the bus */
312static int macii_reset_bus(void)
313{
314 struct adb_request req;
315
316 /* Command = 0, Address = ignored */
317 adb_request(&req, NULL, ADBREQ_NOSEND, 1, ADB_BUSRESET);
318 macii_send_request(&req, 1);
319
320 /* Don't want any more requests during the Global Reset low time. */
321 udelay(3000);
322
323 return 0;
324}
325
326/* Start sending ADB packet */
327static void macii_start(void)
328{
329 struct adb_request *req;
330
331 req = current_req;
332
333 /* Now send it. Be careful though, that first byte of the request
334 * is actually ADB_PACKET; the real data begins at index 1!
335 * And req->nbytes is the number of bytes of real data plus one.
336 */
337
338 /* Output mode */
339 via[ACR] |= SR_OUT;
340 /* Load data */
341 via[SR] = req->data[1];
342 /* set ADB state to 'command' */
343 via[B] = (via[B] & ~ST_MASK) | ST_CMD;
344
345 macii_state = sending;
346 data_index = 2;
347
348 bus_timeout = false;
349 srq_asserted = false;
350}
351
352/*
353 * The notorious ADB interrupt handler - does all of the protocol handling.
354 * Relies on the ADB controller sending and receiving data, thereby
355 * generating shift register interrupts (SR_INT) for us. This means there has
356 * to be activity on the ADB bus. The chip will poll to achieve this.
357 *
358 * The VIA Port B output signalling works as follows. After the ADB transceiver
359 * sees a transition on the PB4 and PB5 lines it will crank over the VIA shift
360 * register which eventually raises the SR_INT interrupt. The PB4/PB5 outputs
361 * are toggled with each byte as the ADB transaction progresses.
362 *
363 * Request with no reply expected (and empty transceiver buffer):
364 * CMD -> IDLE
365 * Request with expected reply packet (or with buffered autopoll packet):
366 * CMD -> EVEN -> ODD -> EVEN -> ... -> IDLE
367 * Unsolicited packet:
368 * IDLE -> EVEN -> ODD -> EVEN -> ... -> IDLE
369 */
370static irqreturn_t macii_interrupt(int irq, void *arg)
371{
372 int x;
373 struct adb_request *req;
374 unsigned long flags;
375
376 local_irq_save(flags);
377
378 if (!arg) {
379 /* Clear the SR IRQ flag when polling. */
380 if (via[IFR] & SR_INT)
381 via[IFR] = SR_INT;
382 else {
383 local_irq_restore(flags);
384 return IRQ_NONE;
385 }
386 }
387
388 status = via[B] & (ST_MASK | CTLR_IRQ);
389
390 switch (macii_state) {
391 case idle:
392 WARN_ON((status & ST_MASK) != ST_IDLE);
393
394 reply_ptr = reply_buf;
395 reading_reply = false;
396
397 bus_timeout = false;
398 srq_asserted = false;
399
400 x = via[SR];
401
402 if (!(status & CTLR_IRQ)) {
403 /* /CTLR_IRQ asserted in idle state means we must
404 * read an autopoll reply from the transceiver buffer.
405 */
406 macii_state = reading;
407 *reply_ptr = x;
408 reply_len = 1;
409 } else {
410 /* bus timeout */
411 reply_len = 0;
412 break;
413 }
414
415 /* set ADB state = even for first data byte */
416 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
417 break;
418
419 case sending:
420 req = current_req;
421
422 if (status == (ST_CMD | CTLR_IRQ)) {
423 /* /CTLR_IRQ de-asserted after the command byte means
424 * the host can continue with the transaction.
425 */
426
427 /* Store command byte */
428 last_cmd = req->data[1];
429 if ((last_cmd & OP_MASK) == TALK) {
430 last_talk_cmd = last_cmd;
431 if ((last_cmd & CMD_MASK) == ADB_READREG(0, 0))
432 last_poll_cmd = last_cmd;
433 }
434 }
435
436 if (status == ST_CMD) {
437 /* /CTLR_IRQ asserted after the command byte means we
438 * must read an autopoll reply. The first byte was
439 * lost because the shift register was an output.
440 */
441 macii_state = reading;
442
443 reading_reply = false;
444 reply_ptr = reply_buf;
445 *reply_ptr = last_talk_cmd;
446 reply_len = 1;
447
448 /* reset to shift in */
449 via[ACR] &= ~SR_OUT;
450 x = via[SR];
451 } else if (data_index >= req->nbytes) {
452 req->sent = 1;
453
454 if (req->reply_expected) {
455 macii_state = reading;
456
457 reading_reply = true;
458 reply_ptr = req->reply;
459 *reply_ptr = req->data[1];
460 reply_len = 1;
461
462 via[ACR] &= ~SR_OUT;
463 x = via[SR];
464 } else if ((req->data[1] & OP_MASK) == TALK) {
465 macii_state = reading;
466
467 reading_reply = false;
468 reply_ptr = reply_buf;
469 *reply_ptr = req->data[1];
470 reply_len = 1;
471
472 via[ACR] &= ~SR_OUT;
473 x = via[SR];
474
475 req->complete = 1;
476 current_req = req->next;
477 if (req->done)
478 (*req->done)(req);
479 } else {
480 macii_state = idle;
481
482 req->complete = 1;
483 current_req = req->next;
484 if (req->done)
485 (*req->done)(req);
486 break;
487 }
488 } else {
489 via[SR] = req->data[data_index++];
490 }
491
492 if ((via[B] & ST_MASK) == ST_CMD) {
493 /* just sent the command byte, set to EVEN */
494 via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
495 } else {
496 /* invert state bits, toggle ODD/EVEN */
497 via[B] ^= ST_MASK;
498 }
499 break;
500
501 case reading:
502 x = via[SR];
503 WARN_ON((status & ST_MASK) == ST_CMD ||
504 (status & ST_MASK) == ST_IDLE);
505
506 if (!(status & CTLR_IRQ)) {
507 if (status == ST_EVEN && reply_len == 1) {
508 bus_timeout = true;
509 } else if (status == ST_ODD && reply_len == 2) {
510 srq_asserted = true;
511 } else {
512 macii_state = idle;
513
514 if (bus_timeout)
515 reply_len = 0;
516
517 if (reading_reply) {
518 struct adb_request *req = current_req;
519
520 req->reply_len = reply_len;
521
522 req->complete = 1;
523 current_req = req->next;
524 if (req->done)
525 (*req->done)(req);
526 } else if (reply_len && autopoll_devs &&
527 reply_buf[0] == last_poll_cmd) {
528 adb_input(reply_buf, reply_len, 1);
529 }
530 break;
531 }
532 }
533
534 if (reply_len < ARRAY_SIZE(reply_buf)) {
535 reply_ptr++;
536 *reply_ptr = x;
537 reply_len++;
538 }
539
540 /* invert state bits, toggle ODD/EVEN */
541 via[B] ^= ST_MASK;
542 break;
543
544 default:
545 break;
546 }
547
548 if (macii_state == idle) {
549 if (!current_req)
550 macii_queue_poll();
551
552 if (current_req)
553 macii_start();
554
555 if (macii_state == idle) {
556 via[ACR] &= ~SR_OUT;
557 x = via[SR];
558 via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
559 }
560 }
561
562 local_irq_restore(flags);
563 return IRQ_HANDLED;
564}