xref: /freebsd/sys/dev/ichiic/ig4_iic.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*
2  * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com> and was subsequently ported
6  * to FreeBSD by Michael Gmelin <freebsd@grem.de>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 /*
40  * Intel fourth generation mobile cpus integrated I2C device.
41  *
42  * See ig4_reg.h for datasheet reference and notes.
43  * See ig4_var.h for locking semantics.
44  */
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/module.h>
50 #include <sys/errno.h>
51 #include <sys/lock.h>
52 #include <sys/mutex.h>
53 #include <sys/sx.h>
54 #include <sys/syslog.h>
55 #include <sys/bus.h>
56 #include <sys/sysctl.h>
57 
58 #include <machine/bus.h>
59 #include <sys/rman.h>
60 
61 #include <dev/pci/pcivar.h>
62 #include <dev/pci/pcireg.h>
63 #include <dev/iicbus/iicbus.h>
64 #include <dev/iicbus/iiconf.h>
65 
66 #include <dev/ichiic/ig4_reg.h>
67 #include <dev/ichiic/ig4_var.h>
68 
69 #define TRANS_NORMAL	1
70 #define TRANS_PCALL	2
71 #define TRANS_BLOCK	3
72 
73 static void ig4iic_start(void *xdev);
74 static void ig4iic_intr(void *cookie);
75 static void ig4iic_dump(ig4iic_softc_t *sc);
76 
77 static int ig4_dump;
78 SYSCTL_INT(_debug, OID_AUTO, ig4_dump, CTLFLAG_RW,
79 	   &ig4_dump, 0, "Dump controller registers");
80 
81 /*
82  * Low-level inline support functions
83  */
84 static __inline void
85 reg_write(ig4iic_softc_t *sc, uint32_t reg, uint32_t value)
86 {
87 	bus_write_4(sc->regs_res, reg, value);
88 	bus_barrier(sc->regs_res, reg, 4, BUS_SPACE_BARRIER_WRITE);
89 }
90 
91 static __inline uint32_t
92 reg_read(ig4iic_softc_t *sc, uint32_t reg)
93 {
94 	uint32_t value;
95 
96 	bus_barrier(sc->regs_res, reg, 4, BUS_SPACE_BARRIER_READ);
97 	value = bus_read_4(sc->regs_res, reg);
98 	return (value);
99 }
100 
101 /*
102  * Enable or disable the controller and wait for the controller to acknowledge
103  * the state change.
104  */
105 static int
106 set_controller(ig4iic_softc_t *sc, uint32_t ctl)
107 {
108 	int retry;
109 	int error;
110 	uint32_t v;
111 
112 	/*
113 	 * When the controller is enabled, interrupt on STOP detect
114 	 * or receive character ready and clear pending interrupts.
115 	 */
116 	if (ctl & IG4_I2C_ENABLE) {
117 		reg_write(sc, IG4_REG_INTR_MASK, IG4_INTR_STOP_DET |
118 						 IG4_INTR_RX_FULL);
119 		reg_read(sc, IG4_REG_CLR_INTR);
120 	} else
121 		reg_write(sc, IG4_REG_INTR_MASK, 0);
122 
123 	reg_write(sc, IG4_REG_I2C_EN, ctl);
124 	error = IIC_ETIMEOUT;
125 
126 	for (retry = 100; retry > 0; --retry) {
127 		v = reg_read(sc, IG4_REG_ENABLE_STATUS);
128 		if (((v ^ ctl) & IG4_I2C_ENABLE) == 0) {
129 			error = 0;
130 			break;
131 		}
132 		if (cold)
133 			DELAY(1000);
134 		else
135 			mtx_sleep(sc, &sc->io_lock, 0, "i2cslv", 1);
136 	}
137 	return (error);
138 }
139 
140 /*
141  * Wait up to 25ms for the requested status using a 25uS polling loop.
142  */
143 static int
144 wait_status(ig4iic_softc_t *sc, uint32_t status)
145 {
146 	uint32_t v;
147 	int error;
148 	int txlvl = -1;
149 	u_int count_us = 0;
150 	u_int limit_us = 25000; /* 25ms */
151 
152 	error = IIC_ETIMEOUT;
153 
154 	for (;;) {
155 		/*
156 		 * Check requested status
157 		 */
158 		v = reg_read(sc, IG4_REG_I2C_STA);
159 		if (v & status) {
160 			error = 0;
161 			break;
162 		}
163 
164 		/*
165 		 * When waiting for receive data break-out if the interrupt
166 		 * loaded data into the FIFO.
167 		 */
168 		if (status & IG4_STATUS_RX_NOTEMPTY) {
169 			if (sc->rpos != sc->rnext) {
170 				error = 0;
171 				break;
172 			}
173 		}
174 
175 		/*
176 		 * When waiting for the transmit FIFO to become empty,
177 		 * reset the timeout if we see a change in the transmit
178 		 * FIFO level as progress is being made.
179 		 */
180 		if (status & IG4_STATUS_TX_EMPTY) {
181 			v = reg_read(sc, IG4_REG_TXFLR) & IG4_FIFOLVL_MASK;
182 			if (txlvl != v) {
183 				txlvl = v;
184 				count_us = 0;
185 			}
186 		}
187 
188 		/*
189 		 * Stop if we've run out of time.
190 		 */
191 		if (count_us >= limit_us)
192 			break;
193 
194 		/*
195 		 * When waiting for receive data let the interrupt do its
196 		 * work, otherwise poll with the lock held.
197 		 */
198 		if (status & IG4_STATUS_RX_NOTEMPTY) {
199 			mtx_sleep(sc, &sc->io_lock, 0, "i2cwait",
200 				  (hz + 99) / 100); /* sleep up to 10ms */
201 			count_us += 10000;
202 		} else {
203 			DELAY(25);
204 			count_us += 25;
205 		}
206 	}
207 
208 	return (error);
209 }
210 
211 /*
212  * Read I2C data.  The data might have already been read by
213  * the interrupt code, otherwise it is sitting in the data
214  * register.
215  */
216 static uint8_t
217 data_read(ig4iic_softc_t *sc)
218 {
219 	uint8_t c;
220 
221 	if (sc->rpos == sc->rnext) {
222 		c = (uint8_t)reg_read(sc, IG4_REG_DATA_CMD);
223 	} else {
224 		c = sc->rbuf[sc->rpos & IG4_RBUFMASK];
225 		++sc->rpos;
226 	}
227 	return (c);
228 }
229 
230 /*
231  * Set the slave address.  The controller must be disabled when
232  * changing the address.
233  *
234  * This operation does not issue anything to the I2C bus but sets
235  * the target address for when the controller later issues a START.
236  */
237 static void
238 set_slave_addr(ig4iic_softc_t *sc, uint8_t slave)
239 {
240 	uint32_t tar;
241 	uint32_t ctl;
242 	int use_10bit;
243 
244 	use_10bit = 0;
245 	if (sc->slave_valid && sc->last_slave == slave &&
246 	    sc->use_10bit == use_10bit) {
247 		return;
248 	}
249 	sc->use_10bit = use_10bit;
250 
251 	/*
252 	 * Wait for TXFIFO to drain before disabling the controller.
253 	 *
254 	 * If a write message has not been completed it's really a
255 	 * programming error, but for now in that case issue an extra
256 	 * byte + STOP.
257 	 *
258 	 * If a read message has not been completed it's also a programming
259 	 * error, for now just ignore it.
260 	 */
261 	wait_status(sc, IG4_STATUS_TX_NOTFULL);
262 	if (sc->write_started) {
263 		reg_write(sc, IG4_REG_DATA_CMD, IG4_DATA_STOP);
264 		sc->write_started = 0;
265 	}
266 	if (sc->read_started)
267 		sc->read_started = 0;
268 	wait_status(sc, IG4_STATUS_TX_EMPTY);
269 
270 	set_controller(sc, 0);
271 	ctl = reg_read(sc, IG4_REG_CTL);
272 	ctl &= ~IG4_CTL_10BIT;
273 	ctl |= IG4_CTL_RESTARTEN;
274 
275 	tar = slave;
276 	if (sc->use_10bit) {
277 		tar |= IG4_TAR_10BIT;
278 		ctl |= IG4_CTL_10BIT;
279 	}
280 	reg_write(sc, IG4_REG_CTL, ctl);
281 	reg_write(sc, IG4_REG_TAR_ADD, tar);
282 	set_controller(sc, IG4_I2C_ENABLE);
283 	sc->slave_valid = 1;
284 	sc->last_slave = slave;
285 }
286 
287 /*
288  *				IICBUS API FUNCTIONS
289  */
290 static int
291 ig4iic_xfer_start(ig4iic_softc_t *sc, uint16_t slave)
292 {
293 	set_slave_addr(sc, slave >> 1);
294 	return (0);
295 }
296 
297 static int
298 ig4iic_read(ig4iic_softc_t *sc, uint8_t *buf, uint16_t len,
299     bool repeated_start, bool stop)
300 {
301 	uint32_t cmd;
302 	uint16_t i;
303 	int error;
304 
305 	if (len == 0)
306 		return (0);
307 
308 	cmd = IG4_DATA_COMMAND_RD;
309 	cmd |= repeated_start ? IG4_DATA_RESTART : 0;
310 	cmd |= stop && len == 1 ? IG4_DATA_STOP : 0;
311 
312 	/* Issue request for the first byte (could be last as well). */
313 	reg_write(sc, IG4_REG_DATA_CMD, cmd);
314 
315 	for (i = 0; i < len; i++) {
316 		/*
317 		 * Maintain a pipeline by queueing the allowance for the next
318 		 * read before waiting for the current read.
319 		 */
320 		cmd = IG4_DATA_COMMAND_RD;
321 		if (i < len - 1) {
322 			cmd = IG4_DATA_COMMAND_RD;
323 			cmd |= stop && i == len - 2 ? IG4_DATA_STOP : 0;
324 			reg_write(sc, IG4_REG_DATA_CMD, cmd);
325 		}
326 		error = wait_status(sc, IG4_STATUS_RX_NOTEMPTY);
327 		if (error)
328 			break;
329 		buf[i] = data_read(sc);
330 	}
331 
332 	(void)reg_read(sc, IG4_REG_TX_ABRT_SOURCE);
333 	return (error);
334 }
335 
336 static int
337 ig4iic_write(ig4iic_softc_t *sc, uint8_t *buf, uint16_t len,
338     bool repeated_start, bool stop)
339 {
340 	uint32_t cmd;
341 	uint16_t i;
342 	int error;
343 
344 	if (len == 0)
345 		return (0);
346 
347 	cmd = repeated_start ? IG4_DATA_RESTART : 0;
348 	for (i = 0; i < len; i++) {
349 		error = wait_status(sc, IG4_STATUS_TX_NOTFULL);
350 		if (error)
351 			break;
352 		cmd |= buf[i];
353 		cmd |= stop && i == len - 1 ? IG4_DATA_STOP : 0;
354 		reg_write(sc, IG4_REG_DATA_CMD, cmd);
355 		cmd = 0;
356 	}
357 
358 	(void)reg_read(sc, IG4_REG_TX_ABRT_SOURCE);
359 	return (error);
360 }
361 
362 int
363 ig4iic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
364 {
365 	ig4iic_softc_t *sc = device_get_softc(dev);
366 	const char *reason = NULL;
367 	uint32_t i;
368 	int error;
369 	int unit;
370 	bool rpstart;
371 	bool stop;
372 
373 	/*
374 	 * The hardware interface imposes limits on allowed I2C messages.
375 	 * It is not possible to explicitly send a start or stop.
376 	 * They are automatically sent (or not sent, depending on the
377 	 * configuration) when a data byte is transferred.
378 	 * For this reason it's impossible to send a message with no data
379 	 * at all (like an SMBus quick message).
380 	 * The start condition is automatically generated after the stop
381 	 * condition, so it's impossible to not have a start after a stop.
382 	 * The repeated start condition is automatically sent if a change
383 	 * of the transfer direction happens, so it's impossible to have
384 	 * a change of direction without a (repeated) start.
385 	 * The repeated start can be forced even without the change of
386 	 * direction.
387 	 * Changing the target slave address requires resetting the hardware
388 	 * state, so it's impossible to do that without the stop followed
389 	 * by the start.
390 	 */
391 	for (i = 0; i < nmsgs; i++) {
392 #if 0
393 		if (i == 0 && (msgs[i].flags & IIC_M_NOSTART) != 0) {
394 			reason = "first message without start";
395 			break;
396 		}
397 		if (i == nmsgs - 1 && (msgs[i].flags & IIC_M_NOSTOP) != 0) {
398 			reason = "last message without stop";
399 			break;
400 		}
401 #endif
402 		if (msgs[i].len == 0) {
403 			reason = "message with no data";
404 			break;
405 		}
406 		if (i > 0) {
407 			if ((msgs[i].flags & IIC_M_NOSTART) != 0 &&
408 			    (msgs[i - 1].flags & IIC_M_NOSTOP) == 0) {
409 				reason = "stop not followed by start";
410 				break;
411 			}
412 			if ((msgs[i - 1].flags & IIC_M_NOSTOP) != 0 &&
413 			    msgs[i].slave != msgs[i - 1].slave) {
414 				reason = "change of slave without stop";
415 				break;
416 			}
417 			if ((msgs[i].flags & IIC_M_NOSTART) != 0 &&
418 			    (msgs[i].flags & IIC_M_RD) !=
419 			    (msgs[i - 1].flags & IIC_M_RD)) {
420 				reason = "change of direction without repeated"
421 				    " start";
422 				break;
423 			}
424 		}
425 	}
426 	if (reason != NULL) {
427 		if (bootverbose)
428 			device_printf(dev, "%s\n", reason);
429 		return (IIC_ENOTSUPP);
430 	}
431 
432 	sx_xlock(&sc->call_lock);
433 	mtx_lock(&sc->io_lock);
434 
435 	/* Debugging - dump registers. */
436 	if (ig4_dump) {
437 		unit = device_get_unit(dev);
438 		if (ig4_dump & (1 << unit)) {
439 			ig4_dump &= ~(1 << unit);
440 			ig4iic_dump(sc);
441 		}
442 	}
443 
444 	/*
445 	 * Clear any previous abort condition that may have been holding
446 	 * the txfifo in reset.
447 	 */
448 	reg_read(sc, IG4_REG_CLR_TX_ABORT);
449 
450 	/*
451 	 * Clean out any previously received data.
452 	 */
453 	if (sc->rpos != sc->rnext && bootverbose) {
454 		device_printf(sc->dev, "discarding %d bytes of spurious data\n",
455 		    sc->rnext - sc->rpos);
456 	}
457 	sc->rpos = 0;
458 	sc->rnext = 0;
459 
460 	rpstart = false;
461 	error = 0;
462 	for (i = 0; i < nmsgs; i++) {
463 		if ((msgs[i].flags & IIC_M_NOSTART) == 0) {
464 			error = ig4iic_xfer_start(sc, msgs[i].slave);
465 		} else {
466 			if (!sc->slave_valid ||
467 			    (msgs[i].slave >> 1) != sc->last_slave) {
468 				device_printf(dev, "start condition suppressed"
469 				    "but slave address is not set up");
470 				error = EINVAL;
471 				break;
472 			}
473 			rpstart = false;
474 		}
475 		if (error != 0)
476 			break;
477 
478 		stop = (msgs[i].flags & IIC_M_NOSTOP) == 0;
479 		if (msgs[i].flags & IIC_M_RD)
480 			error = ig4iic_read(sc, msgs[i].buf, msgs[i].len,
481 			    rpstart, stop);
482 		else
483 			error = ig4iic_write(sc, msgs[i].buf, msgs[i].len,
484 			    rpstart, stop);
485 		if (error != 0)
486 			break;
487 
488 		rpstart = !stop;
489 	}
490 
491 	mtx_unlock(&sc->io_lock);
492 	sx_unlock(&sc->call_lock);
493 	return (error);
494 }
495 
496 int
497 ig4iic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
498 {
499 	ig4iic_softc_t *sc = device_get_softc(dev);
500 
501 	sx_xlock(&sc->call_lock);
502 	mtx_lock(&sc->io_lock);
503 
504 	/* TODO handle speed configuration? */
505 	if (oldaddr != NULL)
506 		*oldaddr = sc->last_slave << 1;
507 	set_slave_addr(sc, addr >> 1);
508 	if (addr == IIC_UNKNOWN)
509 		sc->slave_valid = false;
510 
511 	mtx_unlock(&sc->io_lock);
512 	sx_unlock(&sc->call_lock);
513 	return (0);
514 }
515 
516 /*
517  * Called from ig4iic_pci_attach/detach()
518  */
519 int
520 ig4iic_attach(ig4iic_softc_t *sc)
521 {
522 	int error;
523 	uint32_t v;
524 
525 	mtx_init(&sc->io_lock, "IG4 I/O lock", NULL, MTX_DEF);
526 	sx_init(&sc->call_lock, "IG4 call lock");
527 
528 	v = reg_read(sc, IG4_REG_DEVIDLE_CTRL);
529 	if (sc->version == IG4_SKYLAKE && (v & IG4_RESTORE_REQUIRED) ) {
530 		reg_write(sc, IG4_REG_DEVIDLE_CTRL, IG4_DEVICE_IDLE | IG4_RESTORE_REQUIRED);
531 		reg_write(sc, IG4_REG_DEVIDLE_CTRL, 0);
532 
533 		reg_write(sc, IG4_REG_RESETS_SKL, IG4_RESETS_ASSERT_SKL);
534 		reg_write(sc, IG4_REG_RESETS_SKL, IG4_RESETS_DEASSERT_SKL);
535 		DELAY(1000);
536 	}
537 
538 	if (sc->version == IG4_ATOM)
539 		v = reg_read(sc, IG4_REG_COMP_TYPE);
540 
541 	if (sc->version == IG4_HASWELL || sc->version == IG4_ATOM) {
542 		v = reg_read(sc, IG4_REG_COMP_PARAM1);
543 		v = reg_read(sc, IG4_REG_GENERAL);
544 		/*
545 		 * The content of IG4_REG_GENERAL is different for each
546 		 * controller version.
547 		 */
548 		if (sc->version == IG4_HASWELL &&
549 		    (v & IG4_GENERAL_SWMODE) == 0) {
550 			v |= IG4_GENERAL_SWMODE;
551 			reg_write(sc, IG4_REG_GENERAL, v);
552 			v = reg_read(sc, IG4_REG_GENERAL);
553 		}
554 	}
555 
556 	if (sc->version == IG4_HASWELL) {
557 		v = reg_read(sc, IG4_REG_SW_LTR_VALUE);
558 		v = reg_read(sc, IG4_REG_AUTO_LTR_VALUE);
559 	} else if (sc->version == IG4_SKYLAKE) {
560 		v = reg_read(sc, IG4_REG_ACTIVE_LTR_VALUE);
561 		v = reg_read(sc, IG4_REG_IDLE_LTR_VALUE);
562 	}
563 
564 	if (sc->version == IG4_HASWELL || sc->version == IG4_ATOM) {
565 		v = reg_read(sc, IG4_REG_COMP_VER);
566 		if (v < IG4_COMP_MIN_VER) {
567 			error = ENXIO;
568 			goto done;
569 		}
570 	}
571 	v = reg_read(sc, IG4_REG_SS_SCL_HCNT);
572 	v = reg_read(sc, IG4_REG_SS_SCL_LCNT);
573 	v = reg_read(sc, IG4_REG_FS_SCL_HCNT);
574 	v = reg_read(sc, IG4_REG_FS_SCL_LCNT);
575 	v = reg_read(sc, IG4_REG_SDA_HOLD);
576 
577 	v = reg_read(sc, IG4_REG_SS_SCL_HCNT);
578 	reg_write(sc, IG4_REG_FS_SCL_HCNT, v);
579 	v = reg_read(sc, IG4_REG_SS_SCL_LCNT);
580 	reg_write(sc, IG4_REG_FS_SCL_LCNT, v);
581 
582 	/*
583 	 * Program based on a 25000 Hz clock.  This is a bit of a
584 	 * hack (obviously).  The defaults are 400 and 470 for standard
585 	 * and 60 and 130 for fast.  The defaults for standard fail
586 	 * utterly (presumably cause an abort) because the clock time
587 	 * is ~18.8ms by default.  This brings it down to ~4ms (for now).
588 	 */
589 	reg_write(sc, IG4_REG_SS_SCL_HCNT, 100);
590 	reg_write(sc, IG4_REG_SS_SCL_LCNT, 125);
591 	reg_write(sc, IG4_REG_FS_SCL_HCNT, 100);
592 	reg_write(sc, IG4_REG_FS_SCL_LCNT, 125);
593 
594 	/*
595 	 * Use a threshold of 1 so we get interrupted on each character,
596 	 * allowing us to use mtx_sleep() in our poll code.  Not perfect
597 	 * but this is better than using DELAY() for receiving data.
598 	 *
599 	 * See ig4_var.h for details on interrupt handler synchronization.
600 	 */
601 	reg_write(sc, IG4_REG_RX_TL, 1);
602 
603 	reg_write(sc, IG4_REG_CTL,
604 		  IG4_CTL_MASTER |
605 		  IG4_CTL_SLAVE_DISABLE |
606 		  IG4_CTL_RESTARTEN |
607 		  IG4_CTL_SPEED_STD);
608 
609 	sc->iicbus = device_add_child(sc->dev, "iicbus", -1);
610 	if (sc->iicbus == NULL) {
611 		device_printf(sc->dev, "iicbus driver not found\n");
612 		error = ENXIO;
613 		goto done;
614 	}
615 
616 #if 0
617 	/*
618 	 * Don't do this, it blows up the PCI config
619 	 */
620 	if (sc->version == IG4_HASWELL || sc->version == IG4_ATOM) {
621 		reg_write(sc, IG4_REG_RESETS_HSW, IG4_RESETS_ASSERT_HSW);
622 		reg_write(sc, IG4_REG_RESETS_HSW, IG4_RESETS_DEASSERT_HSW);
623 	} else if (sc->version = IG4_SKYLAKE) {
624 		reg_write(sc, IG4_REG_RESETS_SKL, IG4_RESETS_ASSERT_SKL);
625 		reg_write(sc, IG4_REG_RESETS_SKL, IG4_RESETS_DEASSERT_SKL);
626 	}
627 #endif
628 
629 	mtx_lock(&sc->io_lock);
630 	if (set_controller(sc, 0))
631 		device_printf(sc->dev, "controller error during attach-1\n");
632 	if (set_controller(sc, IG4_I2C_ENABLE))
633 		device_printf(sc->dev, "controller error during attach-2\n");
634 	mtx_unlock(&sc->io_lock);
635 	error = bus_setup_intr(sc->dev, sc->intr_res, INTR_TYPE_MISC | INTR_MPSAFE,
636 			       NULL, ig4iic_intr, sc, &sc->intr_handle);
637 	if (error) {
638 		device_printf(sc->dev,
639 			      "Unable to setup irq: error %d\n", error);
640 	}
641 
642 	sc->enum_hook.ich_func = ig4iic_start;
643 	sc->enum_hook.ich_arg = sc->dev;
644 
645 	/*
646 	 * We have to wait until interrupts are enabled. I2C read and write
647 	 * only works if the interrupts are available.
648 	 */
649 	if (config_intrhook_establish(&sc->enum_hook) != 0)
650 		error = ENOMEM;
651 	else
652 		error = 0;
653 
654 done:
655 	return (error);
656 }
657 
658 void
659 ig4iic_start(void *xdev)
660 {
661 	int error;
662 	ig4iic_softc_t *sc;
663 	device_t dev = (device_t)xdev;
664 
665 	sc = device_get_softc(dev);
666 
667 	config_intrhook_disestablish(&sc->enum_hook);
668 
669 	error = bus_generic_attach(sc->dev);
670 	if (error) {
671 		device_printf(sc->dev,
672 			      "failed to attach child: error %d\n", error);
673 	}
674 }
675 
676 int
677 ig4iic_detach(ig4iic_softc_t *sc)
678 {
679 	int error;
680 
681 	if (device_is_attached(sc->dev)) {
682 		error = bus_generic_detach(sc->dev);
683 		if (error)
684 			return (error);
685 	}
686 	if (sc->iicbus)
687 		device_delete_child(sc->dev, sc->iicbus);
688 	if (sc->intr_handle)
689 		bus_teardown_intr(sc->dev, sc->intr_res, sc->intr_handle);
690 
691 	sx_xlock(&sc->call_lock);
692 	mtx_lock(&sc->io_lock);
693 
694 	sc->iicbus = NULL;
695 	sc->intr_handle = NULL;
696 	reg_write(sc, IG4_REG_INTR_MASK, 0);
697 	set_controller(sc, 0);
698 
699 	mtx_unlock(&sc->io_lock);
700 	sx_xunlock(&sc->call_lock);
701 
702 	mtx_destroy(&sc->io_lock);
703 	sx_destroy(&sc->call_lock);
704 
705 	return (0);
706 }
707 
708 /*
709  * Interrupt Operation, see ig4_var.h for locking semantics.
710  */
711 static void
712 ig4iic_intr(void *cookie)
713 {
714 	ig4iic_softc_t *sc = cookie;
715 	uint32_t status;
716 
717 	mtx_lock(&sc->io_lock);
718 /*	reg_write(sc, IG4_REG_INTR_MASK, IG4_INTR_STOP_DET);*/
719 	reg_read(sc, IG4_REG_CLR_INTR);
720 	status = reg_read(sc, IG4_REG_I2C_STA);
721 	while (status & IG4_STATUS_RX_NOTEMPTY) {
722 		sc->rbuf[sc->rnext & IG4_RBUFMASK] =
723 		    (uint8_t)reg_read(sc, IG4_REG_DATA_CMD);
724 		++sc->rnext;
725 		status = reg_read(sc, IG4_REG_I2C_STA);
726 	}
727 
728 	/*
729 	 * Workaround to trigger pending interrupt if IG4_REG_INTR_STAT
730 	 * is changed after clearing it
731 	 */
732 	if (sc->access_intr_mask != 0) {
733 		status = reg_read(sc, IG4_REG_INTR_MASK);
734 		if (status != 0) {
735 			reg_write(sc, IG4_REG_INTR_MASK, 0);
736 			reg_write(sc, IG4_REG_INTR_MASK, status);
737 		}
738 	}
739 
740 	wakeup(sc);
741 	mtx_unlock(&sc->io_lock);
742 }
743 
744 #define REGDUMP(sc, reg)	\
745 	device_printf(sc->dev, "  %-23s %08x\n", #reg, reg_read(sc, reg))
746 
747 static void
748 ig4iic_dump(ig4iic_softc_t *sc)
749 {
750 	device_printf(sc->dev, "ig4iic register dump:\n");
751 	REGDUMP(sc, IG4_REG_CTL);
752 	REGDUMP(sc, IG4_REG_TAR_ADD);
753 	REGDUMP(sc, IG4_REG_SS_SCL_HCNT);
754 	REGDUMP(sc, IG4_REG_SS_SCL_LCNT);
755 	REGDUMP(sc, IG4_REG_FS_SCL_HCNT);
756 	REGDUMP(sc, IG4_REG_FS_SCL_LCNT);
757 	REGDUMP(sc, IG4_REG_INTR_STAT);
758 	REGDUMP(sc, IG4_REG_INTR_MASK);
759 	REGDUMP(sc, IG4_REG_RAW_INTR_STAT);
760 	REGDUMP(sc, IG4_REG_RX_TL);
761 	REGDUMP(sc, IG4_REG_TX_TL);
762 	REGDUMP(sc, IG4_REG_I2C_EN);
763 	REGDUMP(sc, IG4_REG_I2C_STA);
764 	REGDUMP(sc, IG4_REG_TXFLR);
765 	REGDUMP(sc, IG4_REG_RXFLR);
766 	REGDUMP(sc, IG4_REG_SDA_HOLD);
767 	REGDUMP(sc, IG4_REG_TX_ABRT_SOURCE);
768 	REGDUMP(sc, IG4_REG_SLV_DATA_NACK);
769 	REGDUMP(sc, IG4_REG_DMA_CTRL);
770 	REGDUMP(sc, IG4_REG_DMA_TDLR);
771 	REGDUMP(sc, IG4_REG_DMA_RDLR);
772 	REGDUMP(sc, IG4_REG_SDA_SETUP);
773 	REGDUMP(sc, IG4_REG_ENABLE_STATUS);
774 	if (sc->version == IG4_HASWELL || sc->version == IG4_ATOM) {
775 		REGDUMP(sc, IG4_REG_COMP_PARAM1);
776 		REGDUMP(sc, IG4_REG_COMP_VER);
777 	}
778 	if (sc->version == IG4_ATOM) {
779 		REGDUMP(sc, IG4_REG_COMP_TYPE);
780 		REGDUMP(sc, IG4_REG_CLK_PARMS);
781 	}
782 	if (sc->version == IG4_HASWELL || sc->version == IG4_ATOM) {
783 		REGDUMP(sc, IG4_REG_RESETS_HSW);
784 		REGDUMP(sc, IG4_REG_GENERAL);
785 	} else if (sc->version == IG4_SKYLAKE) {
786 		REGDUMP(sc, IG4_REG_RESETS_SKL);
787 	}
788 	if (sc->version == IG4_HASWELL) {
789 		REGDUMP(sc, IG4_REG_SW_LTR_VALUE);
790 		REGDUMP(sc, IG4_REG_AUTO_LTR_VALUE);
791 	} else if (sc->version == IG4_SKYLAKE) {
792 		REGDUMP(sc, IG4_REG_ACTIVE_LTR_VALUE);
793 		REGDUMP(sc, IG4_REG_IDLE_LTR_VALUE);
794 	}
795 }
796 #undef REGDUMP
797 
798 DRIVER_MODULE(iicbus, ig4iic_acpi, iicbus_driver, iicbus_devclass, NULL, NULL);
799 DRIVER_MODULE(iicbus, ig4iic_pci, iicbus_driver, iicbus_devclass, NULL, NULL);
800