xref: /openbmc/linux/drivers/input/serio/hp_sdc.c (revision dea54fba)
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 	do_gettimeofday(&hp_sdc.rtv);
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 		struct timeval tv;
310 
311 		do_gettimeofday(&tv);
312 		if (tv.tv_sec > hp_sdc.rtv.tv_sec)
313 			tv.tv_usec += USEC_PER_SEC;
314 
315 		if (tv.tv_usec - hp_sdc.rtv.tv_usec > HP_SDC_MAX_REG_DELAY) {
316 			hp_sdc_transaction *curr;
317 			uint8_t tmp;
318 
319 			curr = hp_sdc.tq[hp_sdc.rcurr];
320 			/* If this turns out to be a normal failure mode
321 			 * we'll need to figure out a way to communicate
322 			 * it back to the application. and be less verbose.
323 			 */
324 			printk(KERN_WARNING PREFIX "read timeout (%ius)!\n",
325 			       (int)(tv.tv_usec - hp_sdc.rtv.tv_usec));
326 			curr->idx += hp_sdc.rqty;
327 			hp_sdc.rqty = 0;
328 			tmp = curr->seq[curr->actidx];
329 			curr->seq[curr->actidx] |= HP_SDC_ACT_DEAD;
330 			if (tmp & HP_SDC_ACT_SEMAPHORE)
331 				if (curr->act.semaphore)
332 					up(curr->act.semaphore);
333 
334 			if (tmp & HP_SDC_ACT_CALLBACK) {
335 				/* Note this means that irqhooks may be called
336 				 * in tasklet/bh context.
337 				 */
338 				if (curr->act.irqhook)
339 					curr->act.irqhook(0, NULL, 0, 0);
340 			}
341 
342 			curr->actidx = curr->idx;
343 			curr->idx++;
344 			hp_sdc.rcurr = -1;
345 		}
346 	}
347 	write_unlock_irq(&hp_sdc.rtq_lock);
348 	hp_sdc_put();
349 }
350 
351 unsigned long hp_sdc_put(void)
352 {
353 	hp_sdc_transaction *curr;
354 	uint8_t act;
355 	int idx, curridx;
356 
357 	int limit = 0;
358 
359 	write_lock(&hp_sdc.lock);
360 
361 	/* If i8042 buffers are full, we cannot do anything that
362 	   requires output, so we skip to the administrativa. */
363 	if (hp_sdc.ibf) {
364 		hp_sdc_status_in8();
365 		if (hp_sdc.ibf)
366 			goto finish;
367 	}
368 
369  anew:
370 	/* See if we are in the middle of a sequence. */
371 	if (hp_sdc.wcurr < 0)
372 		hp_sdc.wcurr = 0;
373 	read_lock_irq(&hp_sdc.rtq_lock);
374 	if (hp_sdc.rcurr == hp_sdc.wcurr)
375 		hp_sdc.wcurr++;
376 	read_unlock_irq(&hp_sdc.rtq_lock);
377 	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
378 		hp_sdc.wcurr = 0;
379 	curridx = hp_sdc.wcurr;
380 
381 	if (hp_sdc.tq[curridx] != NULL)
382 		goto start;
383 
384 	while (++curridx != hp_sdc.wcurr) {
385 		if (curridx >= HP_SDC_QUEUE_LEN) {
386 			curridx = -1; /* Wrap to top */
387 			continue;
388 		}
389 		read_lock_irq(&hp_sdc.rtq_lock);
390 		if (hp_sdc.rcurr == curridx) {
391 			read_unlock_irq(&hp_sdc.rtq_lock);
392 			continue;
393 		}
394 		read_unlock_irq(&hp_sdc.rtq_lock);
395 		if (hp_sdc.tq[curridx] != NULL)
396 			break; /* Found one. */
397 	}
398 	if (curridx == hp_sdc.wcurr) { /* There's nothing queued to do. */
399 		curridx = -1;
400 	}
401 	hp_sdc.wcurr = curridx;
402 
403  start:
404 
405 	/* Check to see if the interrupt mask needs to be set. */
406 	if (hp_sdc.set_im) {
407 		hp_sdc_status_out8(hp_sdc.im | HP_SDC_CMD_SET_IM);
408 		hp_sdc.set_im = 0;
409 		goto finish;
410 	}
411 
412 	if (hp_sdc.wcurr == -1)
413 		goto done;
414 
415 	curr = hp_sdc.tq[curridx];
416 	idx = curr->actidx;
417 
418 	if (curr->actidx >= curr->endidx) {
419 		hp_sdc.tq[curridx] = NULL;
420 		/* Interleave outbound data between the transactions. */
421 		hp_sdc.wcurr++;
422 		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
423 			hp_sdc.wcurr = 0;
424 		goto finish;
425 	}
426 
427 	act = curr->seq[idx];
428 	idx++;
429 
430 	if (curr->idx >= curr->endidx) {
431 		if (act & HP_SDC_ACT_DEALLOC)
432 			kfree(curr);
433 		hp_sdc.tq[curridx] = NULL;
434 		/* Interleave outbound data between the transactions. */
435 		hp_sdc.wcurr++;
436 		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
437 			hp_sdc.wcurr = 0;
438 		goto finish;
439 	}
440 
441 	while (act & HP_SDC_ACT_PRECMD) {
442 		if (curr->idx != idx) {
443 			idx++;
444 			act &= ~HP_SDC_ACT_PRECMD;
445 			break;
446 		}
447 		hp_sdc_status_out8(curr->seq[idx]);
448 		curr->idx++;
449 		/* act finished? */
450 		if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_PRECMD)
451 			goto actdone;
452 		/* skip quantity field if data-out sequence follows. */
453 		if (act & HP_SDC_ACT_DATAOUT)
454 			curr->idx++;
455 		goto finish;
456 	}
457 	if (act & HP_SDC_ACT_DATAOUT) {
458 		int qty;
459 
460 		qty = curr->seq[idx];
461 		idx++;
462 		if (curr->idx - idx < qty) {
463 			hp_sdc_data_out8(curr->seq[curr->idx]);
464 			curr->idx++;
465 			/* act finished? */
466 			if (curr->idx - idx >= qty &&
467 			    (act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAOUT)
468 				goto actdone;
469 			goto finish;
470 		}
471 		idx += qty;
472 		act &= ~HP_SDC_ACT_DATAOUT;
473 	} else
474 	    while (act & HP_SDC_ACT_DATAREG) {
475 		int mask;
476 		uint8_t w7[4];
477 
478 		mask = curr->seq[idx];
479 		if (idx != curr->idx) {
480 			idx++;
481 			idx += !!(mask & 1);
482 			idx += !!(mask & 2);
483 			idx += !!(mask & 4);
484 			idx += !!(mask & 8);
485 			act &= ~HP_SDC_ACT_DATAREG;
486 			break;
487 		}
488 
489 		w7[0] = (mask & 1) ? curr->seq[++idx] : hp_sdc.r7[0];
490 		w7[1] = (mask & 2) ? curr->seq[++idx] : hp_sdc.r7[1];
491 		w7[2] = (mask & 4) ? curr->seq[++idx] : hp_sdc.r7[2];
492 		w7[3] = (mask & 8) ? curr->seq[++idx] : hp_sdc.r7[3];
493 
494 		if (hp_sdc.wi > 0x73 || hp_sdc.wi < 0x70 ||
495 		    w7[hp_sdc.wi - 0x70] == hp_sdc.r7[hp_sdc.wi - 0x70]) {
496 			int i = 0;
497 
498 			/* Need to point the write index register */
499 			while (i < 4 && w7[i] == hp_sdc.r7[i])
500 				i++;
501 
502 			if (i < 4) {
503 				hp_sdc_status_out8(HP_SDC_CMD_SET_D0 + i);
504 				hp_sdc.wi = 0x70 + i;
505 				goto finish;
506 			}
507 
508 			idx++;
509 			if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAREG)
510 				goto actdone;
511 
512 			curr->idx = idx;
513 			act &= ~HP_SDC_ACT_DATAREG;
514 			break;
515 		}
516 
517 		hp_sdc_data_out8(w7[hp_sdc.wi - 0x70]);
518 		hp_sdc.r7[hp_sdc.wi - 0x70] = w7[hp_sdc.wi - 0x70];
519 		hp_sdc.wi++; /* write index register autoincrements */
520 		{
521 			int i = 0;
522 
523 			while ((i < 4) && w7[i] == hp_sdc.r7[i])
524 				i++;
525 			if (i >= 4) {
526 				curr->idx = idx + 1;
527 				if ((act & HP_SDC_ACT_DURING) ==
528 				    HP_SDC_ACT_DATAREG)
529 					goto actdone;
530 			}
531 		}
532 		goto finish;
533 	}
534 	/* We don't go any further in the command if there is a pending read,
535 	   because we don't want interleaved results. */
536 	read_lock_irq(&hp_sdc.rtq_lock);
537 	if (hp_sdc.rcurr >= 0) {
538 		read_unlock_irq(&hp_sdc.rtq_lock);
539 		goto finish;
540 	}
541 	read_unlock_irq(&hp_sdc.rtq_lock);
542 
543 
544 	if (act & HP_SDC_ACT_POSTCMD) {
545 		uint8_t postcmd;
546 
547 		/* curr->idx should == idx at this point. */
548 		postcmd = curr->seq[idx];
549 		curr->idx++;
550 		if (act & HP_SDC_ACT_DATAIN) {
551 
552 			/* Start a new read */
553 			hp_sdc.rqty = curr->seq[curr->idx];
554 			do_gettimeofday(&hp_sdc.rtv);
555 			curr->idx++;
556 			/* Still need to lock here in case of spurious irq. */
557 			write_lock_irq(&hp_sdc.rtq_lock);
558 			hp_sdc.rcurr = curridx;
559 			write_unlock_irq(&hp_sdc.rtq_lock);
560 			hp_sdc_status_out8(postcmd);
561 			goto finish;
562 		}
563 		hp_sdc_status_out8(postcmd);
564 		goto actdone;
565 	}
566 
567  actdone:
568 	if (act & HP_SDC_ACT_SEMAPHORE)
569 		up(curr->act.semaphore);
570 	else if (act & HP_SDC_ACT_CALLBACK)
571 		curr->act.irqhook(0,NULL,0,0);
572 
573 	if (curr->idx >= curr->endidx) { /* This transaction is over. */
574 		if (act & HP_SDC_ACT_DEALLOC)
575 			kfree(curr);
576 		hp_sdc.tq[curridx] = NULL;
577 	} else {
578 		curr->actidx = idx + 1;
579 		curr->idx = idx + 2;
580 	}
581 	/* Interleave outbound data between the transactions. */
582 	hp_sdc.wcurr++;
583 	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
584 		hp_sdc.wcurr = 0;
585 
586  finish:
587 	/* If by some quirk IBF has cleared and our ISR has run to
588 	   see that that has happened, do it all again. */
589 	if (!hp_sdc.ibf && limit++ < 20)
590 		goto anew;
591 
592  done:
593 	if (hp_sdc.wcurr >= 0)
594 		tasklet_schedule(&hp_sdc.task);
595 	write_unlock(&hp_sdc.lock);
596 
597 	return 0;
598 }
599 
600 /******* Functions called in either user or kernel context ****/
601 int __hp_sdc_enqueue_transaction(hp_sdc_transaction *this)
602 {
603 	int i;
604 
605 	if (this == NULL) {
606 		BUG();
607 		return -EINVAL;
608 	}
609 
610 	/* Can't have same transaction on queue twice */
611 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
612 		if (hp_sdc.tq[i] == this)
613 			goto fail;
614 
615 	this->actidx = 0;
616 	this->idx = 1;
617 
618 	/* Search for empty slot */
619 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
620 		if (hp_sdc.tq[i] == NULL) {
621 			hp_sdc.tq[i] = this;
622 			tasklet_schedule(&hp_sdc.task);
623 			return 0;
624 		}
625 
626 	printk(KERN_WARNING PREFIX "No free slot to add transaction.\n");
627 	return -EBUSY;
628 
629  fail:
630 	printk(KERN_WARNING PREFIX "Transaction add failed: transaction already queued?\n");
631 	return -EINVAL;
632 }
633 
634 int hp_sdc_enqueue_transaction(hp_sdc_transaction *this) {
635 	unsigned long flags;
636 	int ret;
637 
638 	write_lock_irqsave(&hp_sdc.lock, flags);
639 	ret = __hp_sdc_enqueue_transaction(this);
640 	write_unlock_irqrestore(&hp_sdc.lock,flags);
641 
642 	return ret;
643 }
644 
645 int hp_sdc_dequeue_transaction(hp_sdc_transaction *this)
646 {
647 	unsigned long flags;
648 	int i;
649 
650 	write_lock_irqsave(&hp_sdc.lock, flags);
651 
652 	/* TODO: don't remove it if it's not done. */
653 
654 	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
655 		if (hp_sdc.tq[i] == this)
656 			hp_sdc.tq[i] = NULL;
657 
658 	write_unlock_irqrestore(&hp_sdc.lock, flags);
659 	return 0;
660 }
661 
662 
663 
664 /********************** User context functions **************************/
665 int hp_sdc_request_timer_irq(hp_sdc_irqhook *callback)
666 {
667 	if (callback == NULL || hp_sdc.dev == NULL)
668 		return -EINVAL;
669 
670 	write_lock_irq(&hp_sdc.hook_lock);
671 	if (hp_sdc.timer != NULL) {
672 		write_unlock_irq(&hp_sdc.hook_lock);
673 		return -EBUSY;
674 	}
675 
676 	hp_sdc.timer = callback;
677 	/* Enable interrupts from the timers */
678 	hp_sdc.im &= ~HP_SDC_IM_FH;
679         hp_sdc.im &= ~HP_SDC_IM_PT;
680 	hp_sdc.im &= ~HP_SDC_IM_TIMERS;
681 	hp_sdc.set_im = 1;
682 	write_unlock_irq(&hp_sdc.hook_lock);
683 
684 	tasklet_schedule(&hp_sdc.task);
685 
686 	return 0;
687 }
688 
689 int hp_sdc_request_hil_irq(hp_sdc_irqhook *callback)
690 {
691 	if (callback == NULL || hp_sdc.dev == NULL)
692 		return -EINVAL;
693 
694 	write_lock_irq(&hp_sdc.hook_lock);
695 	if (hp_sdc.hil != NULL) {
696 		write_unlock_irq(&hp_sdc.hook_lock);
697 		return -EBUSY;
698 	}
699 
700 	hp_sdc.hil = callback;
701 	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
702 	hp_sdc.set_im = 1;
703 	write_unlock_irq(&hp_sdc.hook_lock);
704 
705 	tasklet_schedule(&hp_sdc.task);
706 
707 	return 0;
708 }
709 
710 int hp_sdc_request_cooked_irq(hp_sdc_irqhook *callback)
711 {
712 	if (callback == NULL || hp_sdc.dev == NULL)
713 		return -EINVAL;
714 
715 	write_lock_irq(&hp_sdc.hook_lock);
716 	if (hp_sdc.cooked != NULL) {
717 		write_unlock_irq(&hp_sdc.hook_lock);
718 		return -EBUSY;
719 	}
720 
721 	/* Enable interrupts from the HIL MLC */
722 	hp_sdc.cooked = callback;
723 	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
724 	hp_sdc.set_im = 1;
725 	write_unlock_irq(&hp_sdc.hook_lock);
726 
727 	tasklet_schedule(&hp_sdc.task);
728 
729 	return 0;
730 }
731 
732 int hp_sdc_release_timer_irq(hp_sdc_irqhook *callback)
733 {
734 	write_lock_irq(&hp_sdc.hook_lock);
735 	if ((callback != hp_sdc.timer) ||
736 	    (hp_sdc.timer == NULL)) {
737 		write_unlock_irq(&hp_sdc.hook_lock);
738 		return -EINVAL;
739 	}
740 
741 	/* Disable interrupts from the timers */
742 	hp_sdc.timer = NULL;
743 	hp_sdc.im |= HP_SDC_IM_TIMERS;
744 	hp_sdc.im |= HP_SDC_IM_FH;
745 	hp_sdc.im |= HP_SDC_IM_PT;
746 	hp_sdc.set_im = 1;
747 	write_unlock_irq(&hp_sdc.hook_lock);
748 	tasklet_schedule(&hp_sdc.task);
749 
750 	return 0;
751 }
752 
753 int hp_sdc_release_hil_irq(hp_sdc_irqhook *callback)
754 {
755 	write_lock_irq(&hp_sdc.hook_lock);
756 	if ((callback != hp_sdc.hil) ||
757 	    (hp_sdc.hil == NULL)) {
758 		write_unlock_irq(&hp_sdc.hook_lock);
759 		return -EINVAL;
760 	}
761 
762 	hp_sdc.hil = NULL;
763 	/* Disable interrupts from HIL only if there is no cooked driver. */
764 	if(hp_sdc.cooked == NULL) {
765 		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
766 		hp_sdc.set_im = 1;
767 	}
768 	write_unlock_irq(&hp_sdc.hook_lock);
769 	tasklet_schedule(&hp_sdc.task);
770 
771 	return 0;
772 }
773 
774 int hp_sdc_release_cooked_irq(hp_sdc_irqhook *callback)
775 {
776 	write_lock_irq(&hp_sdc.hook_lock);
777 	if ((callback != hp_sdc.cooked) ||
778 	    (hp_sdc.cooked == NULL)) {
779 		write_unlock_irq(&hp_sdc.hook_lock);
780 		return -EINVAL;
781 	}
782 
783 	hp_sdc.cooked = NULL;
784 	/* Disable interrupts from HIL only if there is no raw HIL driver. */
785 	if(hp_sdc.hil == NULL) {
786 		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
787 		hp_sdc.set_im = 1;
788 	}
789 	write_unlock_irq(&hp_sdc.hook_lock);
790 	tasklet_schedule(&hp_sdc.task);
791 
792 	return 0;
793 }
794 
795 /************************* Keepalive timer task *********************/
796 
797 static void hp_sdc_kicker(unsigned long data)
798 {
799 	tasklet_schedule(&hp_sdc.task);
800 	/* Re-insert the periodic task. */
801 	mod_timer(&hp_sdc.kicker, jiffies + HZ);
802 }
803 
804 /************************** Module Initialization ***************************/
805 
806 #if defined(__hppa__)
807 
808 static const struct parisc_device_id hp_sdc_tbl[] = {
809 	{
810 		.hw_type =	HPHW_FIO,
811 		.hversion_rev =	HVERSION_REV_ANY_ID,
812 		.hversion =	HVERSION_ANY_ID,
813 		.sversion =	0x73,
814 	 },
815 	{ 0, }
816 };
817 
818 MODULE_DEVICE_TABLE(parisc, hp_sdc_tbl);
819 
820 static int __init hp_sdc_init_hppa(struct parisc_device *d);
821 static struct delayed_work moduleloader_work;
822 
823 static struct parisc_driver hp_sdc_driver = {
824 	.name =		"hp_sdc",
825 	.id_table =	hp_sdc_tbl,
826 	.probe =	hp_sdc_init_hppa,
827 };
828 
829 #endif /* __hppa__ */
830 
831 static int __init hp_sdc_init(void)
832 {
833 	char *errstr;
834 	hp_sdc_transaction t_sync;
835 	uint8_t ts_sync[6];
836 	struct semaphore s_sync;
837 
838 	rwlock_init(&hp_sdc.lock);
839 	rwlock_init(&hp_sdc.ibf_lock);
840 	rwlock_init(&hp_sdc.rtq_lock);
841 	rwlock_init(&hp_sdc.hook_lock);
842 
843 	hp_sdc.timer		= NULL;
844 	hp_sdc.hil		= NULL;
845 	hp_sdc.pup		= NULL;
846 	hp_sdc.cooked		= NULL;
847 	hp_sdc.im		= HP_SDC_IM_MASK;  /* Mask maskable irqs */
848 	hp_sdc.set_im		= 1;
849 	hp_sdc.wi		= 0xff;
850 	hp_sdc.r7[0]		= 0xff;
851 	hp_sdc.r7[1]		= 0xff;
852 	hp_sdc.r7[2]		= 0xff;
853 	hp_sdc.r7[3]		= 0xff;
854 	hp_sdc.ibf		= 1;
855 
856 	memset(&hp_sdc.tq, 0, sizeof(hp_sdc.tq));
857 
858 	hp_sdc.wcurr		= -1;
859         hp_sdc.rcurr		= -1;
860 	hp_sdc.rqty		= 0;
861 
862 	hp_sdc.dev_err = -ENODEV;
863 
864 	errstr = "IO not found for";
865 	if (!hp_sdc.base_io)
866 		goto err0;
867 
868 	errstr = "IRQ not found for";
869 	if (!hp_sdc.irq)
870 		goto err0;
871 
872 	hp_sdc.dev_err = -EBUSY;
873 
874 #if defined(__hppa__)
875 	errstr = "IO not available for";
876         if (request_region(hp_sdc.data_io, 2, hp_sdc_driver.name))
877 		goto err0;
878 #endif
879 
880 	errstr = "IRQ not available for";
881 	if (request_irq(hp_sdc.irq, &hp_sdc_isr, IRQF_SHARED,
882 			"HP SDC", &hp_sdc))
883 		goto err1;
884 
885 	errstr = "NMI not available for";
886 	if (request_irq(hp_sdc.nmi, &hp_sdc_nmisr, IRQF_SHARED,
887 			"HP SDC NMI", &hp_sdc))
888 		goto err2;
889 
890 	printk(KERN_INFO PREFIX "HP SDC at 0x%p, IRQ %d (NMI IRQ %d)\n",
891 	       (void *)hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
892 
893 	hp_sdc_status_in8();
894 	hp_sdc_data_in8();
895 
896 	tasklet_init(&hp_sdc.task, hp_sdc_tasklet, 0);
897 
898 	/* Sync the output buffer registers, thus scheduling hp_sdc_tasklet. */
899 	t_sync.actidx	= 0;
900 	t_sync.idx	= 1;
901 	t_sync.endidx	= 6;
902 	t_sync.seq	= ts_sync;
903 	ts_sync[0]	= HP_SDC_ACT_DATAREG | HP_SDC_ACT_SEMAPHORE;
904 	ts_sync[1]	= 0x0f;
905 	ts_sync[2] = ts_sync[3]	= ts_sync[4] = ts_sync[5] = 0;
906 	t_sync.act.semaphore = &s_sync;
907 	sema_init(&s_sync, 0);
908 	hp_sdc_enqueue_transaction(&t_sync);
909 	down(&s_sync); /* Wait for t_sync to complete */
910 
911 	/* Create the keepalive task */
912 	init_timer(&hp_sdc.kicker);
913 	hp_sdc.kicker.expires = jiffies + HZ;
914 	hp_sdc.kicker.function = &hp_sdc_kicker;
915 	add_timer(&hp_sdc.kicker);
916 
917 	hp_sdc.dev_err = 0;
918 	return 0;
919  err2:
920 	free_irq(hp_sdc.irq, &hp_sdc);
921  err1:
922 	release_region(hp_sdc.data_io, 2);
923  err0:
924 	printk(KERN_WARNING PREFIX ": %s SDC IO=0x%p IRQ=0x%x NMI=0x%x\n",
925 		errstr, (void *)hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
926 	hp_sdc.dev = NULL;
927 
928 	return hp_sdc.dev_err;
929 }
930 
931 #if defined(__hppa__)
932 
933 static void request_module_delayed(struct work_struct *work)
934 {
935 	request_module("hp_sdc_mlc");
936 }
937 
938 static int __init hp_sdc_init_hppa(struct parisc_device *d)
939 {
940 	int ret;
941 
942 	if (!d)
943 		return 1;
944 	if (hp_sdc.dev != NULL)
945 		return 1;	/* We only expect one SDC */
946 
947 	hp_sdc.dev		= d;
948 	hp_sdc.irq		= d->irq;
949 	hp_sdc.nmi		= d->aux_irq;
950 	hp_sdc.base_io		= d->hpa.start;
951 	hp_sdc.data_io		= d->hpa.start + 0x800;
952 	hp_sdc.status_io	= d->hpa.start + 0x801;
953 
954 	INIT_DELAYED_WORK(&moduleloader_work, request_module_delayed);
955 
956 	ret = hp_sdc_init();
957 	/* after successful initialization give SDC some time to settle
958 	 * and then load the hp_sdc_mlc upper layer driver */
959 	if (!ret)
960 		schedule_delayed_work(&moduleloader_work,
961 			msecs_to_jiffies(2000));
962 
963 	return ret;
964 }
965 
966 #endif /* __hppa__ */
967 
968 static void hp_sdc_exit(void)
969 {
970 	/* do nothing if we don't have a SDC */
971 	if (!hp_sdc.dev)
972 		return;
973 
974 	write_lock_irq(&hp_sdc.lock);
975 
976 	/* Turn off all maskable "sub-function" irq's. */
977 	hp_sdc_spin_ibf();
978 	sdc_writeb(HP_SDC_CMD_SET_IM | HP_SDC_IM_MASK, hp_sdc.status_io);
979 
980 	/* Wait until we know this has been processed by the i8042 */
981 	hp_sdc_spin_ibf();
982 
983 	free_irq(hp_sdc.nmi, &hp_sdc);
984 	free_irq(hp_sdc.irq, &hp_sdc);
985 	write_unlock_irq(&hp_sdc.lock);
986 
987 	del_timer_sync(&hp_sdc.kicker);
988 
989 	tasklet_kill(&hp_sdc.task);
990 
991 #if defined(__hppa__)
992 	cancel_delayed_work_sync(&moduleloader_work);
993 	if (unregister_parisc_driver(&hp_sdc_driver))
994 		printk(KERN_WARNING PREFIX "Error unregistering HP SDC");
995 #endif
996 }
997 
998 static int __init hp_sdc_register(void)
999 {
1000 	hp_sdc_transaction tq_init;
1001 	uint8_t tq_init_seq[5];
1002 	struct semaphore tq_init_sem;
1003 #if defined(__mc68000__)
1004 	unsigned char i;
1005 #endif
1006 
1007 	if (hp_sdc_disabled) {
1008 		printk(KERN_WARNING PREFIX "HP SDC driver disabled by no_hpsdc=1.\n");
1009 		return -ENODEV;
1010 	}
1011 
1012 	hp_sdc.dev = NULL;
1013 	hp_sdc.dev_err = 0;
1014 #if defined(__hppa__)
1015 	if (register_parisc_driver(&hp_sdc_driver)) {
1016 		printk(KERN_WARNING PREFIX "Error registering SDC with system bus tree.\n");
1017 		return -ENODEV;
1018 	}
1019 #elif defined(__mc68000__)
1020 	if (!MACH_IS_HP300)
1021 	    return -ENODEV;
1022 
1023 	hp_sdc.irq	 = 1;
1024 	hp_sdc.nmi	 = 7;
1025 	hp_sdc.base_io	 = (unsigned long) 0xf0428000;
1026 	hp_sdc.data_io	 = (unsigned long) hp_sdc.base_io + 1;
1027 	hp_sdc.status_io = (unsigned long) hp_sdc.base_io + 3;
1028 	if (!probe_kernel_read(&i, (unsigned char *)hp_sdc.data_io, 1))
1029 		hp_sdc.dev = (void *)1;
1030 	hp_sdc.dev_err   = hp_sdc_init();
1031 #endif
1032 	if (hp_sdc.dev == NULL) {
1033 		printk(KERN_WARNING PREFIX "No SDC found.\n");
1034 		return hp_sdc.dev_err;
1035 	}
1036 
1037 	sema_init(&tq_init_sem, 0);
1038 
1039 	tq_init.actidx		= 0;
1040 	tq_init.idx		= 1;
1041 	tq_init.endidx		= 5;
1042 	tq_init.seq		= tq_init_seq;
1043 	tq_init.act.semaphore	= &tq_init_sem;
1044 
1045 	tq_init_seq[0] =
1046 		HP_SDC_ACT_POSTCMD | HP_SDC_ACT_DATAIN | HP_SDC_ACT_SEMAPHORE;
1047 	tq_init_seq[1] = HP_SDC_CMD_READ_KCC;
1048 	tq_init_seq[2] = 1;
1049 	tq_init_seq[3] = 0;
1050 	tq_init_seq[4] = 0;
1051 
1052 	hp_sdc_enqueue_transaction(&tq_init);
1053 
1054 	down(&tq_init_sem);
1055 	up(&tq_init_sem);
1056 
1057 	if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
1058 		printk(KERN_WARNING PREFIX "Error reading config byte.\n");
1059 		hp_sdc_exit();
1060 		return -ENODEV;
1061 	}
1062 	hp_sdc.r11 = tq_init_seq[4];
1063 	if (hp_sdc.r11 & HP_SDC_CFG_NEW) {
1064 		const char *str;
1065 		printk(KERN_INFO PREFIX "New style SDC\n");
1066 		tq_init_seq[1] = HP_SDC_CMD_READ_XTD;
1067 		tq_init.actidx		= 0;
1068 		tq_init.idx		= 1;
1069 		down(&tq_init_sem);
1070 		hp_sdc_enqueue_transaction(&tq_init);
1071 		down(&tq_init_sem);
1072 		up(&tq_init_sem);
1073 		if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
1074 			printk(KERN_WARNING PREFIX "Error reading extended config byte.\n");
1075 			return -ENODEV;
1076 		}
1077 		hp_sdc.r7e = tq_init_seq[4];
1078 		HP_SDC_XTD_REV_STRINGS(hp_sdc.r7e & HP_SDC_XTD_REV, str)
1079 		printk(KERN_INFO PREFIX "Revision: %s\n", str);
1080 		if (hp_sdc.r7e & HP_SDC_XTD_BEEPER)
1081 			printk(KERN_INFO PREFIX "TI SN76494 beeper present\n");
1082 		if (hp_sdc.r7e & HP_SDC_XTD_BBRTC)
1083 			printk(KERN_INFO PREFIX "OKI MSM-58321 BBRTC present\n");
1084 		printk(KERN_INFO PREFIX "Spunking the self test register to force PUP "
1085 		       "on next firmware reset.\n");
1086 		tq_init_seq[0] = HP_SDC_ACT_PRECMD |
1087 			HP_SDC_ACT_DATAOUT | HP_SDC_ACT_SEMAPHORE;
1088 		tq_init_seq[1] = HP_SDC_CMD_SET_STR;
1089 		tq_init_seq[2] = 1;
1090 		tq_init_seq[3] = 0;
1091 		tq_init.actidx		= 0;
1092 		tq_init.idx		= 1;
1093 		tq_init.endidx		= 4;
1094 		down(&tq_init_sem);
1095 		hp_sdc_enqueue_transaction(&tq_init);
1096 		down(&tq_init_sem);
1097 		up(&tq_init_sem);
1098 	} else
1099 		printk(KERN_INFO PREFIX "Old style SDC (1820-%s).\n",
1100 		       (hp_sdc.r11 & HP_SDC_CFG_REV) ? "3300" : "2564/3087");
1101 
1102         return 0;
1103 }
1104 
1105 module_init(hp_sdc_register);
1106 module_exit(hp_sdc_exit);
1107 
1108 /* Timing notes:  These measurements taken on my 64MHz 7100-LC (715/64)
1109  *                                              cycles cycles-adj    time
1110  * between two consecutive mfctl(16)'s:              4        n/a    63ns
1111  * hp_sdc_spin_ibf when idle:                      119        115   1.7us
1112  * gsc_writeb status register:                      83         79   1.2us
1113  * IBF to clear after sending SET_IM:             6204       6006    93us
1114  * IBF to clear after sending LOAD_RT:            4467       4352    68us
1115  * IBF to clear after sending two LOAD_RTs:      18974      18859   295us
1116  * READ_T1, read status/data, IRQ, call handler: 35564        n/a   556us
1117  * cmd to ~IBF READ_T1 2nd time right after:   5158403        n/a    81ms
1118  * between IRQ received and ~IBF for above:    2578877        n/a    40ms
1119  *
1120  * Performance stats after a run of this module configuring HIL and
1121  * receiving a few mouse events:
1122  *
1123  * status in8  282508 cycles 7128 calls
1124  * status out8   8404 cycles  341 calls
1125  * data out8     1734 cycles   78 calls
1126  * isr         174324 cycles  617 calls (includes take)
1127  * take          1241 cycles    2 calls
1128  * put        1411504 cycles 6937 calls
1129  * task       1655209 cycles 6937 calls (includes put)
1130  *
1131  */
1132