xref: /openbmc/linux/drivers/input/serio/hp_sdc.c (revision be709d48)
1 /*
2  * HP i8042-based System Device Controller driver.
3  *
4  * Copyright (c) 2001 Brian S. Julin
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions, and the following disclaimer,
12  *    without modification.
13  * 2. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * Alternatively, this software may be distributed under the terms of the
17  * GNU General Public License ("GPL").
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
23  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  *
29  * References:
30  * System Device Controller Microprocessor Firmware Theory of Operation
31  *      for Part Number 1820-4784 Revision B.  Dwg No. A-1820-4784-2
32  * Helge Deller's original hilkbd.c port for PA-RISC.
33  *
34  *
35  * Driver theory of operation:
36  *
37  * hp_sdc_put does all writing to the SDC.  ISR can run on a different
38  * CPU than hp_sdc_put, but only one CPU runs hp_sdc_put at a time
39  * (it cannot really benefit from SMP anyway.)  A tasket fit this perfectly.
40  *
41  * All data coming back from the SDC is sent via interrupt and can be read
42  * fully in the ISR, so there are no latency/throughput problems there.
43  * The problem is with output, due to the slow clock speed of the SDC
44  * compared to the CPU.  This should not be too horrible most of the time,
45  * but if used with HIL devices that support the multibyte transfer command,
46  * keeping outbound throughput flowing at the 6500KBps that the HIL is
47  * capable of is more than can be done at HZ=100.
48  *
49  * Busy polling for IBF clear wastes CPU cycles and bus cycles.  hp_sdc.ibf
50  * is set to 0 when the IBF flag in the status register has cleared.  ISR
51  * may do this, and may also access the parts of queued transactions related
52  * to reading data back from the SDC, but otherwise will not touch the
53  * hp_sdc state. Whenever a register is written hp_sdc.ibf is set to 1.
54  *
55  * The i8042 write index and the values in the 4-byte input buffer
56  * starting at 0x70 are kept track of in hp_sdc.wi, and .r7[], respectively,
57  * to minimize the amount of IO needed to the SDC.  However these values
58  * do not need to be locked since they are only ever accessed by hp_sdc_put.
59  *
60  * A timer task schedules the tasklet once per second just to make
61  * sure it doesn't freeze up and to allow for bad reads to time out.
62  */
63 
64 #include <linux/hp_sdc.h>
65 #include <linux/errno.h>
66 #include <linux/init.h>
67 #include <linux/module.h>
68 #include <linux/ioport.h>
69 #include <linux/time.h>
70 #include <linux/semaphore.h>
71 #include <linux/slab.h>
72 #include <linux/hil.h>
73 #include <asm/io.h>
74 
75 /* Machine-specific abstraction */
76 
77 #if defined(__hppa__)
78 # include <asm/parisc-device.h>
79 # define sdc_readb(p)		gsc_readb(p)
80 # define sdc_writeb(v,p)	gsc_writeb((v),(p))
81 #elif defined(__mc68000__)
82 #include <linux/uaccess.h>
83 # define sdc_readb(p)		in_8(p)
84 # define sdc_writeb(v,p)	out_8((p),(v))
85 #else
86 # error "HIL is not supported on this platform"
87 #endif
88 
89 #define PREFIX "HP SDC: "
90 
91 MODULE_AUTHOR("Brian S. Julin <bri@calyx.com>");
92 MODULE_DESCRIPTION("HP i8042-based SDC Driver");
93 MODULE_LICENSE("Dual BSD/GPL");
94 
95 EXPORT_SYMBOL(hp_sdc_request_timer_irq);
96 EXPORT_SYMBOL(hp_sdc_request_hil_irq);
97 EXPORT_SYMBOL(hp_sdc_request_cooked_irq);
98 
99 EXPORT_SYMBOL(hp_sdc_release_timer_irq);
100 EXPORT_SYMBOL(hp_sdc_release_hil_irq);
101 EXPORT_SYMBOL(hp_sdc_release_cooked_irq);
102 
103 EXPORT_SYMBOL(__hp_sdc_enqueue_transaction);
104 EXPORT_SYMBOL(hp_sdc_enqueue_transaction);
105 EXPORT_SYMBOL(hp_sdc_dequeue_transaction);
106 
107 static bool hp_sdc_disabled;
108 module_param_named(no_hpsdc, hp_sdc_disabled, bool, 0);
109 MODULE_PARM_DESC(no_hpsdc, "Do not enable HP SDC driver.");
110 
111 static hp_i8042_sdc	hp_sdc;	/* All driver state is kept in here. */
112 
113 /*************** primitives for use in any context *********************/
114 static inline uint8_t hp_sdc_status_in8(void)
115 {
116 	uint8_t status;
117 	unsigned long flags;
118 
119 	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
120 	status = sdc_readb(hp_sdc.status_io);
121 	if (!(status & HP_SDC_STATUS_IBF))
122 		hp_sdc.ibf = 0;
123 	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
124 
125 	return status;
126 }
127 
128 static inline uint8_t hp_sdc_data_in8(void)
129 {
130 	return sdc_readb(hp_sdc.data_io);
131 }
132 
133 static inline void hp_sdc_status_out8(uint8_t val)
134 {
135 	unsigned long flags;
136 
137 	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
138 	hp_sdc.ibf = 1;
139 	if ((val & 0xf0) == 0xe0)
140 		hp_sdc.wi = 0xff;
141 	sdc_writeb(val, hp_sdc.status_io);
142 	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
143 }
144 
145 static inline void hp_sdc_data_out8(uint8_t val)
146 {
147 	unsigned long flags;
148 
149 	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
150 	hp_sdc.ibf = 1;
151 	sdc_writeb(val, hp_sdc.data_io);
152 	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
153 }
154 
155 /*	Care must be taken to only invoke hp_sdc_spin_ibf when
156  *	absolutely needed, or in rarely invoked subroutines.
157  *	Not only does it waste CPU cycles, it also wastes bus cycles.
158  */
159 static inline void hp_sdc_spin_ibf(void)
160 {
161 	unsigned long flags;
162 	rwlock_t *lock;
163 
164 	lock = &hp_sdc.ibf_lock;
165 
166 	read_lock_irqsave(lock, flags);
167 	if (!hp_sdc.ibf) {
168 		read_unlock_irqrestore(lock, flags);
169 		return;
170 	}
171 	read_unlock(lock);
172 	write_lock(lock);
173 	while (sdc_readb(hp_sdc.status_io) & HP_SDC_STATUS_IBF)
174 		{ }
175 	hp_sdc.ibf = 0;
176 	write_unlock_irqrestore(lock, flags);
177 }
178 
179 
180 /************************ Interrupt context functions ************************/
181 static void hp_sdc_take(int irq, void *dev_id, uint8_t status, uint8_t data)
182 {
183 	hp_sdc_transaction *curr;
184 
185 	read_lock(&hp_sdc.rtq_lock);
186 	if (hp_sdc.rcurr < 0) {
187 		read_unlock(&hp_sdc.rtq_lock);
188 		return;
189 	}
190 	curr = hp_sdc.tq[hp_sdc.rcurr];
191 	read_unlock(&hp_sdc.rtq_lock);
192 
193 	curr->seq[curr->idx++] = status;
194 	curr->seq[curr->idx++] = data;
195 	hp_sdc.rqty -= 2;
196 	hp_sdc.rtime = ktime_get();
197 
198 	if (hp_sdc.rqty <= 0) {
199 		/* All data has been gathered. */
200 		if (curr->seq[curr->actidx] & HP_SDC_ACT_SEMAPHORE)
201 			if (curr->act.semaphore)
202 				up(curr->act.semaphore);
203 
204 		if (curr->seq[curr->actidx] & HP_SDC_ACT_CALLBACK)
205 			if (curr->act.irqhook)
206 				curr->act.irqhook(irq, dev_id, status, data);
207 
208 		curr->actidx = curr->idx;
209 		curr->idx++;
210 		/* Return control of this transaction */
211 		write_lock(&hp_sdc.rtq_lock);
212 		hp_sdc.rcurr = -1;
213 		hp_sdc.rqty = 0;
214 		write_unlock(&hp_sdc.rtq_lock);
215 		tasklet_schedule(&hp_sdc.task);
216 	}
217 }
218 
219 static irqreturn_t hp_sdc_isr(int irq, void *dev_id)
220 {
221 	uint8_t status, data;
222 
223 	status = hp_sdc_status_in8();
224 	/* Read data unconditionally to advance i8042. */
225 	data =   hp_sdc_data_in8();
226 
227 	/* For now we are ignoring these until we get the SDC to behave. */
228 	if (((status & 0xf1) == 0x51) && data == 0x82)
229 		return IRQ_HANDLED;
230 
231 	switch (status & HP_SDC_STATUS_IRQMASK) {
232 	case 0: /* This case is not documented. */
233 		break;
234 
235 	case HP_SDC_STATUS_USERTIMER:
236 	case HP_SDC_STATUS_PERIODIC:
237 	case HP_SDC_STATUS_TIMER:
238 		read_lock(&hp_sdc.hook_lock);
239 		if (hp_sdc.timer != NULL)
240 			hp_sdc.timer(irq, dev_id, status, data);
241 		read_unlock(&hp_sdc.hook_lock);
242 		break;
243 
244 	case HP_SDC_STATUS_REG:
245 		hp_sdc_take(irq, dev_id, status, data);
246 		break;
247 
248 	case HP_SDC_STATUS_HILCMD:
249 	case HP_SDC_STATUS_HILDATA:
250 		read_lock(&hp_sdc.hook_lock);
251 		if (hp_sdc.hil != NULL)
252 			hp_sdc.hil(irq, dev_id, status, data);
253 		read_unlock(&hp_sdc.hook_lock);
254 		break;
255 
256 	case HP_SDC_STATUS_PUP:
257 		read_lock(&hp_sdc.hook_lock);
258 		if (hp_sdc.pup != NULL)
259 			hp_sdc.pup(irq, dev_id, status, data);
260 		else
261 			printk(KERN_INFO PREFIX "HP SDC reports successful PUP.\n");
262 		read_unlock(&hp_sdc.hook_lock);
263 		break;
264 
265 	default:
266 		read_lock(&hp_sdc.hook_lock);
267 		if (hp_sdc.cooked != NULL)
268 			hp_sdc.cooked(irq, dev_id, status, data);
269 		read_unlock(&hp_sdc.hook_lock);
270 		break;
271 	}
272 
273 	return IRQ_HANDLED;
274 }
275 
276 
277 static irqreturn_t hp_sdc_nmisr(int irq, void *dev_id)
278 {
279 	int status;
280 
281 	status = hp_sdc_status_in8();
282 	printk(KERN_WARNING PREFIX "NMI !\n");
283 
284 #if 0
285 	if (status & HP_SDC_NMISTATUS_FHS) {
286 		read_lock(&hp_sdc.hook_lock);
287 		if (hp_sdc.timer != NULL)
288 			hp_sdc.timer(irq, dev_id, status, 0);
289 		read_unlock(&hp_sdc.hook_lock);
290 	} else {
291 		/* TODO: pass this on to the HIL handler, or do SAK here? */
292 		printk(KERN_WARNING PREFIX "HIL NMI\n");
293 	}
294 #endif
295 
296 	return IRQ_HANDLED;
297 }
298 
299 
300 /***************** Kernel (tasklet) context functions ****************/
301 
302 unsigned long hp_sdc_put(void);
303 
304 static void hp_sdc_tasklet(unsigned long foo)
305 {
306 	write_lock_irq(&hp_sdc.rtq_lock);
307 
308 	if (hp_sdc.rcurr >= 0) {
309 		ktime_t now = ktime_get();
310 
311 		if (ktime_after(now, ktime_add_us(hp_sdc.rtime,
312 						  HP_SDC_MAX_REG_DELAY))) {
313 			hp_sdc_transaction *curr;
314 			uint8_t tmp;
315 
316 			curr = hp_sdc.tq[hp_sdc.rcurr];
317 			/* If this turns out to be a normal failure mode
318 			 * we'll need to figure out a way to communicate
319 			 * it back to the application. and be less verbose.
320 			 */
321 			printk(KERN_WARNING PREFIX "read timeout (%lldus)!\n",
322 			       ktime_us_delta(now, hp_sdc.rtime));
323 			curr->idx += hp_sdc.rqty;
324 			hp_sdc.rqty = 0;
325 			tmp = curr->seq[curr->actidx];
326 			curr->seq[curr->actidx] |= HP_SDC_ACT_DEAD;
327 			if (tmp & HP_SDC_ACT_SEMAPHORE)
328 				if (curr->act.semaphore)
329 					up(curr->act.semaphore);
330 
331 			if (tmp & HP_SDC_ACT_CALLBACK) {
332 				/* Note this means that irqhooks may be called
333 				 * in tasklet/bh context.
334 				 */
335 				if (curr->act.irqhook)
336 					curr->act.irqhook(0, NULL, 0, 0);
337 			}
338 
339 			curr->actidx = curr->idx;
340 			curr->idx++;
341 			hp_sdc.rcurr = -1;
342 		}
343 	}
344 	write_unlock_irq(&hp_sdc.rtq_lock);
345 	hp_sdc_put();
346 }
347 
348 unsigned long hp_sdc_put(void)
349 {
350 	hp_sdc_transaction *curr;
351 	uint8_t act;
352 	int idx, curridx;
353 
354 	int limit = 0;
355 
356 	write_lock(&hp_sdc.lock);
357 
358 	/* If i8042 buffers are full, we cannot do anything that
359 	   requires output, so we skip to the administrativa. */
360 	if (hp_sdc.ibf) {
361 		hp_sdc_status_in8();
362 		if (hp_sdc.ibf)
363 			goto finish;
364 	}
365 
366  anew:
367 	/* See if we are in the middle of a sequence. */
368 	if (hp_sdc.wcurr < 0)
369 		hp_sdc.wcurr = 0;
370 	read_lock_irq(&hp_sdc.rtq_lock);
371 	if (hp_sdc.rcurr == hp_sdc.wcurr)
372 		hp_sdc.wcurr++;
373 	read_unlock_irq(&hp_sdc.rtq_lock);
374 	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
375 		hp_sdc.wcurr = 0;
376 	curridx = hp_sdc.wcurr;
377 
378 	if (hp_sdc.tq[curridx] != NULL)
379 		goto start;
380 
381 	while (++curridx != hp_sdc.wcurr) {
382 		if (curridx >= HP_SDC_QUEUE_LEN) {
383 			curridx = -1; /* Wrap to top */
384 			continue;
385 		}
386 		read_lock_irq(&hp_sdc.rtq_lock);
387 		if (hp_sdc.rcurr == curridx) {
388 			read_unlock_irq(&hp_sdc.rtq_lock);
389 			continue;
390 		}
391 		read_unlock_irq(&hp_sdc.rtq_lock);
392 		if (hp_sdc.tq[curridx] != NULL)
393 			break; /* Found one. */
394 	}
395 	if (curridx == hp_sdc.wcurr) { /* There's nothing queued to do. */
396 		curridx = -1;
397 	}
398 	hp_sdc.wcurr = curridx;
399 
400  start:
401 
402 	/* Check to see if the interrupt mask needs to be set. */
403 	if (hp_sdc.set_im) {
404 		hp_sdc_status_out8(hp_sdc.im | HP_SDC_CMD_SET_IM);
405 		hp_sdc.set_im = 0;
406 		goto finish;
407 	}
408 
409 	if (hp_sdc.wcurr == -1)
410 		goto done;
411 
412 	curr = hp_sdc.tq[curridx];
413 	idx = curr->actidx;
414 
415 	if (curr->actidx >= curr->endidx) {
416 		hp_sdc.tq[curridx] = NULL;
417 		/* Interleave outbound data between the transactions. */
418 		hp_sdc.wcurr++;
419 		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
420 			hp_sdc.wcurr = 0;
421 		goto finish;
422 	}
423 
424 	act = curr->seq[idx];
425 	idx++;
426 
427 	if (curr->idx >= curr->endidx) {
428 		if (act & HP_SDC_ACT_DEALLOC)
429 			kfree(curr);
430 		hp_sdc.tq[curridx] = NULL;
431 		/* Interleave outbound data between the transactions. */
432 		hp_sdc.wcurr++;
433 		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
434 			hp_sdc.wcurr = 0;
435 		goto finish;
436 	}
437 
438 	while (act & HP_SDC_ACT_PRECMD) {
439 		if (curr->idx != idx) {
440 			idx++;
441 			act &= ~HP_SDC_ACT_PRECMD;
442 			break;
443 		}
444 		hp_sdc_status_out8(curr->seq[idx]);
445 		curr->idx++;
446 		/* act finished? */
447 		if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_PRECMD)
448 			goto actdone;
449 		/* skip quantity field if data-out sequence follows. */
450 		if (act & HP_SDC_ACT_DATAOUT)
451 			curr->idx++;
452 		goto finish;
453 	}
454 	if (act & HP_SDC_ACT_DATAOUT) {
455 		int qty;
456 
457 		qty = curr->seq[idx];
458 		idx++;
459 		if (curr->idx - idx < qty) {
460 			hp_sdc_data_out8(curr->seq[curr->idx]);
461 			curr->idx++;
462 			/* act finished? */
463 			if (curr->idx - idx >= qty &&
464 			    (act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAOUT)
465 				goto actdone;
466 			goto finish;
467 		}
468 		idx += qty;
469 		act &= ~HP_SDC_ACT_DATAOUT;
470 	} else
471 	    while (act & HP_SDC_ACT_DATAREG) {
472 		int mask;
473 		uint8_t w7[4];
474 
475 		mask = curr->seq[idx];
476 		if (idx != curr->idx) {
477 			idx++;
478 			idx += !!(mask & 1);
479 			idx += !!(mask & 2);
480 			idx += !!(mask & 4);
481 			idx += !!(mask & 8);
482 			act &= ~HP_SDC_ACT_DATAREG;
483 			break;
484 		}
485 
486 		w7[0] = (mask & 1) ? curr->seq[++idx] : hp_sdc.r7[0];
487 		w7[1] = (mask & 2) ? curr->seq[++idx] : hp_sdc.r7[1];
488 		w7[2] = (mask & 4) ? curr->seq[++idx] : hp_sdc.r7[2];
489 		w7[3] = (mask & 8) ? curr->seq[++idx] : hp_sdc.r7[3];
490 
491 		if (hp_sdc.wi > 0x73 || hp_sdc.wi < 0x70 ||
492 		    w7[hp_sdc.wi - 0x70] == hp_sdc.r7[hp_sdc.wi - 0x70]) {
493 			int i = 0;
494 
495 			/* Need to point the write index register */
496 			while (i < 4 && w7[i] == hp_sdc.r7[i])
497 				i++;
498 
499 			if (i < 4) {
500 				hp_sdc_status_out8(HP_SDC_CMD_SET_D0 + i);
501 				hp_sdc.wi = 0x70 + i;
502 				goto finish;
503 			}
504 
505 			idx++;
506 			if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAREG)
507 				goto actdone;
508 
509 			curr->idx = idx;
510 			act &= ~HP_SDC_ACT_DATAREG;
511 			break;
512 		}
513 
514 		hp_sdc_data_out8(w7[hp_sdc.wi - 0x70]);
515 		hp_sdc.r7[hp_sdc.wi - 0x70] = w7[hp_sdc.wi - 0x70];
516 		hp_sdc.wi++; /* write index register autoincrements */
517 		{
518 			int i = 0;
519 
520 			while ((i < 4) && w7[i] == hp_sdc.r7[i])
521 				i++;
522 			if (i >= 4) {
523 				curr->idx = idx + 1;
524 				if ((act & HP_SDC_ACT_DURING) ==
525 				    HP_SDC_ACT_DATAREG)
526 					goto actdone;
527 			}
528 		}
529 		goto finish;
530 	}
531 	/* We don't go any further in the command if there is a pending read,
532 	   because we don't want interleaved results. */
533 	read_lock_irq(&hp_sdc.rtq_lock);
534 	if (hp_sdc.rcurr >= 0) {
535 		read_unlock_irq(&hp_sdc.rtq_lock);
536 		goto finish;
537 	}
538 	read_unlock_irq(&hp_sdc.rtq_lock);
539 
540 
541 	if (act & HP_SDC_ACT_POSTCMD) {
542 		uint8_t postcmd;
543 
544 		/* curr->idx should == idx at this point. */
545 		postcmd = curr->seq[idx];
546 		curr->idx++;
547 		if (act & HP_SDC_ACT_DATAIN) {
548 
549 			/* Start a new read */
550 			hp_sdc.rqty = curr->seq[curr->idx];
551 			hp_sdc.rtime = ktime_get();
552 			curr->idx++;
553 			/* Still need to lock here in case of spurious irq. */
554 			write_lock_irq(&hp_sdc.rtq_lock);
555 			hp_sdc.rcurr = curridx;
556 			write_unlock_irq(&hp_sdc.rtq_lock);
557 			hp_sdc_status_out8(postcmd);
558 			goto finish;
559 		}
560 		hp_sdc_status_out8(postcmd);
561 		goto actdone;
562 	}
563 
564  actdone:
565 	if (act & HP_SDC_ACT_SEMAPHORE)
566 		up(curr->act.semaphore);
567 	else if (act & HP_SDC_ACT_CALLBACK)
568 		curr->act.irqhook(0,NULL,0,0);
569 
570 	if (curr->idx >= curr->endidx) { /* This transaction is over. */
571 		if (act & HP_SDC_ACT_DEALLOC)
572 			kfree(curr);
573 		hp_sdc.tq[curridx] = NULL;
574 	} else {
575 		curr->actidx = idx + 1;
576 		curr->idx = idx + 2;
577 	}
578 	/* Interleave outbound data between the transactions. */
579 	hp_sdc.wcurr++;
580 	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
581 		hp_sdc.wcurr = 0;
582 
583  finish:
584 	/* If by some quirk IBF has cleared and our ISR has run to
585 	   see that that has happened, do it all again. */
586 	if (!hp_sdc.ibf && limit++ < 20)
587 		goto anew;
588 
589  done:
590 	if (hp_sdc.wcurr >= 0)
591 		tasklet_schedule(&hp_sdc.task);
592 	write_unlock(&hp_sdc.lock);
593 
594 	return 0;
595 }
596 
597 /******* Functions called in either user or kernel context ****/
598 int __hp_sdc_enqueue_transaction(hp_sdc_transaction *this)
599 {
600 	int i;
601 
602 	if (this == NULL) {
603 		BUG();
604 		return -EINVAL;
605 	}
606 
607 	/* Can't have same transaction on queue twice */
608 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
609 		if (hp_sdc.tq[i] == this)
610 			goto fail;
611 
612 	this->actidx = 0;
613 	this->idx = 1;
614 
615 	/* Search for empty slot */
616 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
617 		if (hp_sdc.tq[i] == NULL) {
618 			hp_sdc.tq[i] = this;
619 			tasklet_schedule(&hp_sdc.task);
620 			return 0;
621 		}
622 
623 	printk(KERN_WARNING PREFIX "No free slot to add transaction.\n");
624 	return -EBUSY;
625 
626  fail:
627 	printk(KERN_WARNING PREFIX "Transaction add failed: transaction already queued?\n");
628 	return -EINVAL;
629 }
630 
631 int hp_sdc_enqueue_transaction(hp_sdc_transaction *this) {
632 	unsigned long flags;
633 	int ret;
634 
635 	write_lock_irqsave(&hp_sdc.lock, flags);
636 	ret = __hp_sdc_enqueue_transaction(this);
637 	write_unlock_irqrestore(&hp_sdc.lock,flags);
638 
639 	return ret;
640 }
641 
642 int hp_sdc_dequeue_transaction(hp_sdc_transaction *this)
643 {
644 	unsigned long flags;
645 	int i;
646 
647 	write_lock_irqsave(&hp_sdc.lock, flags);
648 
649 	/* TODO: don't remove it if it's not done. */
650 
651 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
652 		if (hp_sdc.tq[i] == this)
653 			hp_sdc.tq[i] = NULL;
654 
655 	write_unlock_irqrestore(&hp_sdc.lock, flags);
656 	return 0;
657 }
658 
659 
660 
661 /********************** User context functions **************************/
662 int hp_sdc_request_timer_irq(hp_sdc_irqhook *callback)
663 {
664 	if (callback == NULL || hp_sdc.dev == NULL)
665 		return -EINVAL;
666 
667 	write_lock_irq(&hp_sdc.hook_lock);
668 	if (hp_sdc.timer != NULL) {
669 		write_unlock_irq(&hp_sdc.hook_lock);
670 		return -EBUSY;
671 	}
672 
673 	hp_sdc.timer = callback;
674 	/* Enable interrupts from the timers */
675 	hp_sdc.im &= ~HP_SDC_IM_FH;
676         hp_sdc.im &= ~HP_SDC_IM_PT;
677 	hp_sdc.im &= ~HP_SDC_IM_TIMERS;
678 	hp_sdc.set_im = 1;
679 	write_unlock_irq(&hp_sdc.hook_lock);
680 
681 	tasklet_schedule(&hp_sdc.task);
682 
683 	return 0;
684 }
685 
686 int hp_sdc_request_hil_irq(hp_sdc_irqhook *callback)
687 {
688 	if (callback == NULL || hp_sdc.dev == NULL)
689 		return -EINVAL;
690 
691 	write_lock_irq(&hp_sdc.hook_lock);
692 	if (hp_sdc.hil != NULL) {
693 		write_unlock_irq(&hp_sdc.hook_lock);
694 		return -EBUSY;
695 	}
696 
697 	hp_sdc.hil = callback;
698 	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
699 	hp_sdc.set_im = 1;
700 	write_unlock_irq(&hp_sdc.hook_lock);
701 
702 	tasklet_schedule(&hp_sdc.task);
703 
704 	return 0;
705 }
706 
707 int hp_sdc_request_cooked_irq(hp_sdc_irqhook *callback)
708 {
709 	if (callback == NULL || hp_sdc.dev == NULL)
710 		return -EINVAL;
711 
712 	write_lock_irq(&hp_sdc.hook_lock);
713 	if (hp_sdc.cooked != NULL) {
714 		write_unlock_irq(&hp_sdc.hook_lock);
715 		return -EBUSY;
716 	}
717 
718 	/* Enable interrupts from the HIL MLC */
719 	hp_sdc.cooked = callback;
720 	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
721 	hp_sdc.set_im = 1;
722 	write_unlock_irq(&hp_sdc.hook_lock);
723 
724 	tasklet_schedule(&hp_sdc.task);
725 
726 	return 0;
727 }
728 
729 int hp_sdc_release_timer_irq(hp_sdc_irqhook *callback)
730 {
731 	write_lock_irq(&hp_sdc.hook_lock);
732 	if ((callback != hp_sdc.timer) ||
733 	    (hp_sdc.timer == NULL)) {
734 		write_unlock_irq(&hp_sdc.hook_lock);
735 		return -EINVAL;
736 	}
737 
738 	/* Disable interrupts from the timers */
739 	hp_sdc.timer = NULL;
740 	hp_sdc.im |= HP_SDC_IM_TIMERS;
741 	hp_sdc.im |= HP_SDC_IM_FH;
742 	hp_sdc.im |= HP_SDC_IM_PT;
743 	hp_sdc.set_im = 1;
744 	write_unlock_irq(&hp_sdc.hook_lock);
745 	tasklet_schedule(&hp_sdc.task);
746 
747 	return 0;
748 }
749 
750 int hp_sdc_release_hil_irq(hp_sdc_irqhook *callback)
751 {
752 	write_lock_irq(&hp_sdc.hook_lock);
753 	if ((callback != hp_sdc.hil) ||
754 	    (hp_sdc.hil == NULL)) {
755 		write_unlock_irq(&hp_sdc.hook_lock);
756 		return -EINVAL;
757 	}
758 
759 	hp_sdc.hil = NULL;
760 	/* Disable interrupts from HIL only if there is no cooked driver. */
761 	if(hp_sdc.cooked == NULL) {
762 		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
763 		hp_sdc.set_im = 1;
764 	}
765 	write_unlock_irq(&hp_sdc.hook_lock);
766 	tasklet_schedule(&hp_sdc.task);
767 
768 	return 0;
769 }
770 
771 int hp_sdc_release_cooked_irq(hp_sdc_irqhook *callback)
772 {
773 	write_lock_irq(&hp_sdc.hook_lock);
774 	if ((callback != hp_sdc.cooked) ||
775 	    (hp_sdc.cooked == NULL)) {
776 		write_unlock_irq(&hp_sdc.hook_lock);
777 		return -EINVAL;
778 	}
779 
780 	hp_sdc.cooked = NULL;
781 	/* Disable interrupts from HIL only if there is no raw HIL driver. */
782 	if(hp_sdc.hil == NULL) {
783 		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
784 		hp_sdc.set_im = 1;
785 	}
786 	write_unlock_irq(&hp_sdc.hook_lock);
787 	tasklet_schedule(&hp_sdc.task);
788 
789 	return 0;
790 }
791 
792 /************************* Keepalive timer task *********************/
793 
794 static void hp_sdc_kicker(struct timer_list *unused)
795 {
796 	tasklet_schedule(&hp_sdc.task);
797 	/* Re-insert the periodic task. */
798 	mod_timer(&hp_sdc.kicker, jiffies + HZ);
799 }
800 
801 /************************** Module Initialization ***************************/
802 
803 #if defined(__hppa__)
804 
805 static const struct parisc_device_id hp_sdc_tbl[] __initconst = {
806 	{
807 		.hw_type =	HPHW_FIO,
808 		.hversion_rev =	HVERSION_REV_ANY_ID,
809 		.hversion =	HVERSION_ANY_ID,
810 		.sversion =	0x73,
811 	 },
812 	{ 0, }
813 };
814 
815 MODULE_DEVICE_TABLE(parisc, hp_sdc_tbl);
816 
817 static int __init hp_sdc_init_hppa(struct parisc_device *d);
818 static struct delayed_work moduleloader_work;
819 
820 static struct parisc_driver hp_sdc_driver __refdata = {
821 	.name =		"hp_sdc",
822 	.id_table =	hp_sdc_tbl,
823 	.probe =	hp_sdc_init_hppa,
824 };
825 
826 #endif /* __hppa__ */
827 
828 static int __init hp_sdc_init(void)
829 {
830 	char *errstr;
831 	hp_sdc_transaction t_sync;
832 	uint8_t ts_sync[6];
833 	struct semaphore s_sync;
834 
835 	rwlock_init(&hp_sdc.lock);
836 	rwlock_init(&hp_sdc.ibf_lock);
837 	rwlock_init(&hp_sdc.rtq_lock);
838 	rwlock_init(&hp_sdc.hook_lock);
839 
840 	hp_sdc.timer		= NULL;
841 	hp_sdc.hil		= NULL;
842 	hp_sdc.pup		= NULL;
843 	hp_sdc.cooked		= NULL;
844 	hp_sdc.im		= HP_SDC_IM_MASK;  /* Mask maskable irqs */
845 	hp_sdc.set_im		= 1;
846 	hp_sdc.wi		= 0xff;
847 	hp_sdc.r7[0]		= 0xff;
848 	hp_sdc.r7[1]		= 0xff;
849 	hp_sdc.r7[2]		= 0xff;
850 	hp_sdc.r7[3]		= 0xff;
851 	hp_sdc.ibf		= 1;
852 
853 	memset(&hp_sdc.tq, 0, sizeof(hp_sdc.tq));
854 
855 	hp_sdc.wcurr		= -1;
856         hp_sdc.rcurr		= -1;
857 	hp_sdc.rqty		= 0;
858 
859 	hp_sdc.dev_err = -ENODEV;
860 
861 	errstr = "IO not found for";
862 	if (!hp_sdc.base_io)
863 		goto err0;
864 
865 	errstr = "IRQ not found for";
866 	if (!hp_sdc.irq)
867 		goto err0;
868 
869 	hp_sdc.dev_err = -EBUSY;
870 
871 #if defined(__hppa__)
872 	errstr = "IO not available for";
873         if (request_region(hp_sdc.data_io, 2, hp_sdc_driver.name))
874 		goto err0;
875 #endif
876 
877 	errstr = "IRQ not available for";
878 	if (request_irq(hp_sdc.irq, &hp_sdc_isr, IRQF_SHARED,
879 			"HP SDC", &hp_sdc))
880 		goto err1;
881 
882 	errstr = "NMI not available for";
883 	if (request_irq(hp_sdc.nmi, &hp_sdc_nmisr, IRQF_SHARED,
884 			"HP SDC NMI", &hp_sdc))
885 		goto err2;
886 
887 	pr_info(PREFIX "HP SDC at 0x%08lx, IRQ %d (NMI IRQ %d)\n",
888 	       hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
889 
890 	hp_sdc_status_in8();
891 	hp_sdc_data_in8();
892 
893 	tasklet_init(&hp_sdc.task, hp_sdc_tasklet, 0);
894 
895 	/* Sync the output buffer registers, thus scheduling hp_sdc_tasklet. */
896 	t_sync.actidx	= 0;
897 	t_sync.idx	= 1;
898 	t_sync.endidx	= 6;
899 	t_sync.seq	= ts_sync;
900 	ts_sync[0]	= HP_SDC_ACT_DATAREG | HP_SDC_ACT_SEMAPHORE;
901 	ts_sync[1]	= 0x0f;
902 	ts_sync[2] = ts_sync[3]	= ts_sync[4] = ts_sync[5] = 0;
903 	t_sync.act.semaphore = &s_sync;
904 	sema_init(&s_sync, 0);
905 	hp_sdc_enqueue_transaction(&t_sync);
906 	down(&s_sync); /* Wait for t_sync to complete */
907 
908 	/* Create the keepalive task */
909 	timer_setup(&hp_sdc.kicker, hp_sdc_kicker, 0);
910 	hp_sdc.kicker.expires = jiffies + HZ;
911 	add_timer(&hp_sdc.kicker);
912 
913 	hp_sdc.dev_err = 0;
914 	return 0;
915  err2:
916 	free_irq(hp_sdc.irq, &hp_sdc);
917  err1:
918 	release_region(hp_sdc.data_io, 2);
919  err0:
920 	printk(KERN_WARNING PREFIX ": %s SDC IO=0x%p IRQ=0x%x NMI=0x%x\n",
921 		errstr, (void *)hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
922 	hp_sdc.dev = NULL;
923 
924 	return hp_sdc.dev_err;
925 }
926 
927 #if defined(__hppa__)
928 
929 static void request_module_delayed(struct work_struct *work)
930 {
931 	request_module("hp_sdc_mlc");
932 }
933 
934 static int __init hp_sdc_init_hppa(struct parisc_device *d)
935 {
936 	int ret;
937 
938 	if (!d)
939 		return 1;
940 	if (hp_sdc.dev != NULL)
941 		return 1;	/* We only expect one SDC */
942 
943 	hp_sdc.dev		= d;
944 	hp_sdc.irq		= d->irq;
945 	hp_sdc.nmi		= d->aux_irq;
946 	hp_sdc.base_io		= d->hpa.start;
947 	hp_sdc.data_io		= d->hpa.start + 0x800;
948 	hp_sdc.status_io	= d->hpa.start + 0x801;
949 
950 	INIT_DELAYED_WORK(&moduleloader_work, request_module_delayed);
951 
952 	ret = hp_sdc_init();
953 	/* after successful initialization give SDC some time to settle
954 	 * and then load the hp_sdc_mlc upper layer driver */
955 	if (!ret)
956 		schedule_delayed_work(&moduleloader_work,
957 			msecs_to_jiffies(2000));
958 
959 	return ret;
960 }
961 
962 #endif /* __hppa__ */
963 
964 static void hp_sdc_exit(void)
965 {
966 	/* do nothing if we don't have a SDC */
967 	if (!hp_sdc.dev)
968 		return;
969 
970 	write_lock_irq(&hp_sdc.lock);
971 
972 	/* Turn off all maskable "sub-function" irq's. */
973 	hp_sdc_spin_ibf();
974 	sdc_writeb(HP_SDC_CMD_SET_IM | HP_SDC_IM_MASK, hp_sdc.status_io);
975 
976 	/* Wait until we know this has been processed by the i8042 */
977 	hp_sdc_spin_ibf();
978 
979 	free_irq(hp_sdc.nmi, &hp_sdc);
980 	free_irq(hp_sdc.irq, &hp_sdc);
981 	write_unlock_irq(&hp_sdc.lock);
982 
983 	del_timer_sync(&hp_sdc.kicker);
984 
985 	tasklet_kill(&hp_sdc.task);
986 
987 #if defined(__hppa__)
988 	cancel_delayed_work_sync(&moduleloader_work);
989 	if (unregister_parisc_driver(&hp_sdc_driver))
990 		printk(KERN_WARNING PREFIX "Error unregistering HP SDC");
991 #endif
992 }
993 
994 static int __init hp_sdc_register(void)
995 {
996 	hp_sdc_transaction tq_init;
997 	uint8_t tq_init_seq[5];
998 	struct semaphore tq_init_sem;
999 #if defined(__mc68000__)
1000 	unsigned char i;
1001 #endif
1002 
1003 	if (hp_sdc_disabled) {
1004 		printk(KERN_WARNING PREFIX "HP SDC driver disabled by no_hpsdc=1.\n");
1005 		return -ENODEV;
1006 	}
1007 
1008 	hp_sdc.dev = NULL;
1009 	hp_sdc.dev_err = 0;
1010 #if defined(__hppa__)
1011 	if (register_parisc_driver(&hp_sdc_driver)) {
1012 		printk(KERN_WARNING PREFIX "Error registering SDC with system bus tree.\n");
1013 		return -ENODEV;
1014 	}
1015 #elif defined(__mc68000__)
1016 	if (!MACH_IS_HP300)
1017 	    return -ENODEV;
1018 
1019 	hp_sdc.irq	 = 1;
1020 	hp_sdc.nmi	 = 7;
1021 	hp_sdc.base_io	 = (unsigned long) 0xf0428000;
1022 	hp_sdc.data_io	 = (unsigned long) hp_sdc.base_io + 1;
1023 	hp_sdc.status_io = (unsigned long) hp_sdc.base_io + 3;
1024 	if (!probe_kernel_read(&i, (unsigned char *)hp_sdc.data_io, 1))
1025 		hp_sdc.dev = (void *)1;
1026 	hp_sdc.dev_err   = hp_sdc_init();
1027 #endif
1028 	if (hp_sdc.dev == NULL) {
1029 		printk(KERN_WARNING PREFIX "No SDC found.\n");
1030 		return hp_sdc.dev_err;
1031 	}
1032 
1033 	sema_init(&tq_init_sem, 0);
1034 
1035 	tq_init.actidx		= 0;
1036 	tq_init.idx		= 1;
1037 	tq_init.endidx		= 5;
1038 	tq_init.seq		= tq_init_seq;
1039 	tq_init.act.semaphore	= &tq_init_sem;
1040 
1041 	tq_init_seq[0] =
1042 		HP_SDC_ACT_POSTCMD | HP_SDC_ACT_DATAIN | HP_SDC_ACT_SEMAPHORE;
1043 	tq_init_seq[1] = HP_SDC_CMD_READ_KCC;
1044 	tq_init_seq[2] = 1;
1045 	tq_init_seq[3] = 0;
1046 	tq_init_seq[4] = 0;
1047 
1048 	hp_sdc_enqueue_transaction(&tq_init);
1049 
1050 	down(&tq_init_sem);
1051 	up(&tq_init_sem);
1052 
1053 	if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
1054 		printk(KERN_WARNING PREFIX "Error reading config byte.\n");
1055 		hp_sdc_exit();
1056 		return -ENODEV;
1057 	}
1058 	hp_sdc.r11 = tq_init_seq[4];
1059 	if (hp_sdc.r11 & HP_SDC_CFG_NEW) {
1060 		const char *str;
1061 		printk(KERN_INFO PREFIX "New style SDC\n");
1062 		tq_init_seq[1] = HP_SDC_CMD_READ_XTD;
1063 		tq_init.actidx		= 0;
1064 		tq_init.idx		= 1;
1065 		down(&tq_init_sem);
1066 		hp_sdc_enqueue_transaction(&tq_init);
1067 		down(&tq_init_sem);
1068 		up(&tq_init_sem);
1069 		if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
1070 			printk(KERN_WARNING PREFIX "Error reading extended config byte.\n");
1071 			return -ENODEV;
1072 		}
1073 		hp_sdc.r7e = tq_init_seq[4];
1074 		HP_SDC_XTD_REV_STRINGS(hp_sdc.r7e & HP_SDC_XTD_REV, str)
1075 		printk(KERN_INFO PREFIX "Revision: %s\n", str);
1076 		if (hp_sdc.r7e & HP_SDC_XTD_BEEPER)
1077 			printk(KERN_INFO PREFIX "TI SN76494 beeper present\n");
1078 		if (hp_sdc.r7e & HP_SDC_XTD_BBRTC)
1079 			printk(KERN_INFO PREFIX "OKI MSM-58321 BBRTC present\n");
1080 		printk(KERN_INFO PREFIX "Spunking the self test register to force PUP "
1081 		       "on next firmware reset.\n");
1082 		tq_init_seq[0] = HP_SDC_ACT_PRECMD |
1083 			HP_SDC_ACT_DATAOUT | HP_SDC_ACT_SEMAPHORE;
1084 		tq_init_seq[1] = HP_SDC_CMD_SET_STR;
1085 		tq_init_seq[2] = 1;
1086 		tq_init_seq[3] = 0;
1087 		tq_init.actidx		= 0;
1088 		tq_init.idx		= 1;
1089 		tq_init.endidx		= 4;
1090 		down(&tq_init_sem);
1091 		hp_sdc_enqueue_transaction(&tq_init);
1092 		down(&tq_init_sem);
1093 		up(&tq_init_sem);
1094 	} else
1095 		printk(KERN_INFO PREFIX "Old style SDC (1820-%s).\n",
1096 		       (hp_sdc.r11 & HP_SDC_CFG_REV) ? "3300" : "2564/3087");
1097 
1098         return 0;
1099 }
1100 
1101 module_init(hp_sdc_register);
1102 module_exit(hp_sdc_exit);
1103 
1104 /* Timing notes:  These measurements taken on my 64MHz 7100-LC (715/64)
1105  *                                              cycles cycles-adj    time
1106  * between two consecutive mfctl(16)'s:              4        n/a    63ns
1107  * hp_sdc_spin_ibf when idle:                      119        115   1.7us
1108  * gsc_writeb status register:                      83         79   1.2us
1109  * IBF to clear after sending SET_IM:             6204       6006    93us
1110  * IBF to clear after sending LOAD_RT:            4467       4352    68us
1111  * IBF to clear after sending two LOAD_RTs:      18974      18859   295us
1112  * READ_T1, read status/data, IRQ, call handler: 35564        n/a   556us
1113  * cmd to ~IBF READ_T1 2nd time right after:   5158403        n/a    81ms
1114  * between IRQ received and ~IBF for above:    2578877        n/a    40ms
1115  *
1116  * Performance stats after a run of this module configuring HIL and
1117  * receiving a few mouse events:
1118  *
1119  * status in8  282508 cycles 7128 calls
1120  * status out8   8404 cycles  341 calls
1121  * data out8     1734 cycles   78 calls
1122  * isr         174324 cycles  617 calls (includes take)
1123  * take          1241 cycles    2 calls
1124  * put        1411504 cycles 6937 calls
1125  * task       1655209 cycles 6937 calls (includes put)
1126  *
1127  */
1128