xref: /dragonfly/sys/bus/smbus/ichiic/ig4_iic.c (revision 3568afc1)
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>
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  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 /*
35  * Intel 4th generation mobile cpus integrated I2C device, smbus driver.
36  *
37  * See ig4_reg.h for datasheet reference and notes.
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
44 #include <sys/errno.h>
45 #include <sys/lock.h>
46 #include <sys/syslog.h>
47 #include <sys/bus.h>
48 #include <sys/sysctl.h>
49 
50 #include <sys/rman.h>
51 
52 #include <bus/pci/pcivar.h>
53 #include <bus/pci/pcireg.h>
54 #include <bus/smbus/smbconf.h>
55 
56 #include "smbus_if.h"
57 
58 #include "ig4_reg.h"
59 #include "ig4_var.h"
60 
61 #define TRANS_NORMAL	1
62 #define TRANS_PCALL	2
63 #define TRANS_BLOCK	3
64 
65 static void ig4iic_intr(void *cookie);
66 static void ig4iic_dump(ig4iic_softc_t *sc);
67 
68 static int ig4_dump;
69 SYSCTL_INT(_debug, OID_AUTO, ig4_dump, CTLTYPE_INT | CTLFLAG_RW,
70 	   &ig4_dump, 0, "");
71 
72 /*
73  * Low-level inline support functions
74  */
75 static __inline
76 void
77 reg_write(ig4iic_softc_t *sc, uint32_t reg, uint32_t value)
78 {
79 	bus_space_write_4(sc->regs_t, sc->regs_h, reg, value);
80 	bus_space_barrier(sc->regs_t, sc->regs_h, reg, 4,
81 			  BUS_SPACE_BARRIER_WRITE);
82 }
83 
84 static __inline
85 uint32_t
86 reg_read(ig4iic_softc_t *sc, uint32_t reg)
87 {
88 	uint32_t value;
89 
90 	bus_space_barrier(sc->regs_t, sc->regs_h, reg, 4,
91 			  BUS_SPACE_BARRIER_READ);
92 	value = bus_space_read_4(sc->regs_t, sc->regs_h, reg);
93 	return value;
94 }
95 
96 /*
97  * Enable or disable the controller and wait for the controller to acknowledge
98  * the state change.
99  */
100 static
101 int
102 set_controller(ig4iic_softc_t *sc, uint32_t ctl)
103 {
104 	int retry;
105 	int error;
106 	uint32_t v;
107 
108 	if (ctl & IG4_I2C_ENABLE) {
109 		reg_write(sc, IG4_REG_INTR_MASK, IG4_INTR_STOP_DET |
110 						 IG4_INTR_RX_FULL);
111 		reg_read(sc, IG4_REG_CLR_INTR);
112 	} else {
113 		reg_write(sc, IG4_REG_INTR_MASK, 0);
114 	}
115 	reg_write(sc, IG4_REG_I2C_EN, ctl);
116 	error = SMB_ETIMEOUT;
117 
118 	for (retry = 100; retry > 0; --retry) {
119 		v = reg_read(sc, IG4_REG_ENABLE_STATUS);
120 		if (((v ^ ctl) & IG4_I2C_ENABLE) == 0) {
121 			error = 0;
122 			break;
123 		}
124 		tsleep(sc, 0, "i2cslv", 1);
125 	}
126 	return error;
127 }
128 
129 /*
130  * Wait up to 25ms for the requested status using a 25uS polling loop.
131  */
132 static
133 int
134 wait_status(ig4iic_softc_t *sc, uint32_t status)
135 {
136 	uint32_t v;
137 	int error;
138 	int txlvl = -1;
139 	sysclock_t count;
140 	sysclock_t limit;
141 
142 	error = SMB_ETIMEOUT;
143 	count = sys_cputimer->count();
144 	limit = sys_cputimer->freq / 40;
145 
146 	for (;;) {
147 		/*
148 		 * Check requested status
149 		 */
150 		v = reg_read(sc, IG4_REG_I2C_STA);
151 		if (v & status) {
152 			error = 0;
153 			break;
154 		}
155 
156 		/*
157 		 * When waiting for receive data break-out if the interrupt
158 		 * loaded data into the FIFO.
159 		 */
160 		if (status & IG4_STATUS_RX_NOTEMPTY) {
161 			if (sc->rpos != sc->rnext) {
162 				error = 0;
163 				break;
164 			}
165 		}
166 
167 		/*
168 		 * When waiting for the transmit FIFO to become empty,
169 		 * reset the timeout if we see a change in the transmit
170 		 * FIFO level as progress is being made.
171 		 */
172 		if (status & IG4_STATUS_TX_EMPTY) {
173 			v = reg_read(sc, IG4_REG_TXFLR) & IG4_FIFOLVL_MASK;
174 			if (txlvl != v) {
175 				txlvl = v;
176 				count = sys_cputimer->count();
177 			}
178 		}
179 
180 		/*
181 		 * Stop if we've run out of time.
182 		 */
183 		if (sys_cputimer->count() - count > limit)
184 			break;
185 
186 		/*
187 		 * When waiting for receive data let the interrupt do its
188 		 * work, otherwise poll with the lock held.
189 		 */
190 		if (status & IG4_STATUS_RX_NOTEMPTY) {
191 			lksleep(sc, &sc->lk, 0, "i2cwait", (hz + 99) / 100);
192 		} else {
193 			DELAY(25);
194 		}
195 	}
196 
197 	return error;
198 }
199 
200 /*
201  * Read I2C data.  The data might have already been read by
202  * the interrupt code, otherwise it is sitting in the data
203  * register.
204  */
205 static
206 uint8_t
207 data_read(ig4iic_softc_t *sc)
208 {
209 	uint8_t c;
210 
211 	if (sc->rpos == sc->rnext) {
212 		c = (uint8_t)reg_read(sc, IG4_REG_DATA_CMD);
213 	} else {
214 		c = sc->rbuf[sc->rpos & IG4_RBUFMASK];
215 		++sc->rpos;
216 	}
217 	return c;
218 }
219 
220 /*
221  * Set the slave address.  The controller must be disabled when
222  * changing the address.
223  *
224  * This operation does not issue anything to the I2C bus but sets
225  * the target address for when the controller later issues a START.
226  */
227 static
228 void
229 set_slave_addr(ig4iic_softc_t *sc, uint8_t slave, int trans_op)
230 {
231 	uint32_t tar;
232 	uint32_t ctl;
233 	int use_10bit;
234 
235 	use_10bit = sc->use_10bit;
236 	if (trans_op & SMB_TRANS_7BIT)
237 		use_10bit = 0;
238 	if (trans_op & SMB_TRANS_10BIT)
239 		use_10bit = 1;
240 
241 	if (sc->slave_valid && sc->last_slave == slave &&
242 	    sc->use_10bit == use_10bit) {
243 		return;
244 	}
245 	sc->use_10bit = use_10bit;
246 
247 	/*
248 	 * Wait for TXFIFO to drain before disabling the controller.
249 	 *
250 	 * If a write message has not been completed it's really a
251 	 * programming error, but for now in that case issue an extra
252 	 * byte + STOP.
253 	 *
254 	 * If a read message has not been completed it's also a programming
255 	 * error, for now just ignore it.
256 	 */
257 	wait_status(sc, IG4_STATUS_TX_NOTFULL);
258 	if (sc->write_started) {
259 		reg_write(sc, IG4_REG_DATA_CMD, IG4_DATA_STOP);
260 		sc->write_started = 0;
261 	}
262 	if (sc->read_started)
263 		sc->read_started = 0;
264 	wait_status(sc, IG4_STATUS_TX_EMPTY);
265 
266 	set_controller(sc, 0);
267 	ctl = reg_read(sc, IG4_REG_CTL);
268 	ctl &= ~IG4_CTL_10BIT;
269 	ctl |= IG4_CTL_RESTARTEN;
270 
271 	tar = slave;
272 	if (sc->use_10bit) {
273 		tar |= IG4_TAR_10BIT;
274 		ctl |= IG4_CTL_10BIT;
275 	}
276 	reg_write(sc, IG4_REG_CTL, ctl);
277 	reg_write(sc, IG4_REG_TAR_ADD, tar);
278 	set_controller(sc, IG4_I2C_ENABLE);
279 	sc->slave_valid = 1;
280 	sc->last_slave = slave;
281 }
282 
283 /*
284  * Issue START with byte command, possible count, and a variable length
285  * read or write buffer, then possible turn-around read.  The read also
286  * has a possible count received.
287  *
288  * For SMBUS -
289  *
290  * Quick:		START+ADDR+RD/WR STOP
291  *
292  * Normal:		START+ADDR+WR CMD DATA..DATA STOP
293  *
294  *			START+ADDR+RD CMD
295  *			RESTART+ADDR RDATA..RDATA STOP
296  *			(can also be used for I2C transactions)
297  *
298  * Process Call:	START+ADDR+WR CMD DATAL DATAH
299  *			RESTART+ADDR+RD RDATAL RDATAH STOP
300  *
301  * Block:		START+ADDR+RD CMD
302  *			RESTART+ADDR+RD RCOUNT DATA... STOP
303  *
304  * 			START+ADDR+WR CMD
305  *			RESTART+ADDR+WR WCOUNT DATA... STOP
306  *
307  * For I2C - basically, no *COUNT fields, possibly no *CMD field.  If the
308  *	     sender needs to issue a 2-byte command it will incorporate it
309  *	     into the write buffer and also set NOCMD.
310  *
311  * Generally speaking, the START+ADDR / RESTART+ADDR is handled automatically
312  * by the controller at the beginning of a command sequence or on a data
313  * direction turn-around, and we only need to tell it when to issue the STOP.
314  */
315 static int
316 smb_transaction(ig4iic_softc_t *sc, char cmd, int op,
317 		char *wbuf, int wcount, char *rbuf, int rcount, int *actualp)
318 {
319 	int error;
320 	int unit;
321 	uint32_t last;
322 
323 	/*
324 	 * Debugging - dump registers
325 	 */
326 	if (ig4_dump) {
327 		unit = device_get_unit(sc->dev);
328 		if (ig4_dump & (1 << unit)) {
329 			ig4_dump &= ~(1 << unit);
330 			ig4iic_dump(sc);
331 		}
332 	}
333 
334 	/*
335 	 * Issue START or RESTART with next data byte, clear any previous
336 	 * abort condition that may have been holding the txfifo in reset.
337 	 */
338 	last = IG4_DATA_RESTART;
339 	reg_read(sc, IG4_REG_CLR_TX_ABORT);
340 	if (actualp)
341 		*actualp = 0;
342 
343 	/*
344 	 * Issue command if not told otherwise (smbus).
345 	 */
346 	if ((op & SMB_TRANS_NOCMD) == 0) {
347 		error = wait_status(sc, IG4_STATUS_TX_NOTFULL);
348 		if (error)
349 			goto done;
350 		last |= (u_char)cmd;
351 		if (wcount == 0 && rcount == 0 && (op & SMB_TRANS_NOSTOP) == 0)
352 			last |= IG4_DATA_STOP;
353 		reg_write(sc, IG4_REG_DATA_CMD, last);
354 		last = 0;
355 	}
356 
357 	/*
358 	 * Clean out any previously received data.
359 	 */
360 	if (sc->rpos != sc->rnext &&
361 	    (op & SMB_TRANS_NOREPORT) == 0) {
362 		device_printf(sc->dev,
363 			      "discarding %d bytes of spurious data\n",
364 			      sc->rnext - sc->rpos);
365 	}
366 	sc->rpos = 0;
367 	sc->rnext = 0;
368 
369 	/*
370 	 * If writing and not told otherwise, issue the write count (smbus).
371 	 */
372 	if (wcount && (op & SMB_TRANS_NOCNT) == 0) {
373 		error = wait_status(sc, IG4_STATUS_TX_NOTFULL);
374 		if (error)
375 			goto done;
376 		last |= (u_char)cmd;
377 		reg_write(sc, IG4_REG_DATA_CMD, last);
378 		last = 0;
379 	}
380 
381 	/*
382 	 * Bulk write (i2c)
383 	 */
384 	while (wcount) {
385 		error = wait_status(sc, IG4_STATUS_TX_NOTFULL);
386 		if (error)
387 			goto done;
388 		last |= (u_char)*wbuf;
389 		if (wcount == 1 && rcount == 0 && (op & SMB_TRANS_NOSTOP) == 0)
390 			last |= IG4_DATA_STOP;
391 		reg_write(sc, IG4_REG_DATA_CMD, last);
392 		--wcount;
393 		++wbuf;
394 		last = 0;
395 	}
396 
397 	/*
398 	 * Issue reads to xmit FIFO (strange, I know) to tell the controller
399 	 * to clock in data.  At the moment just issue one read ahead to
400 	 * pipeline the incoming data.
401 	 *
402 	 * NOTE: In the case of NOCMD and wcount == 0 we still issue a
403 	 *	 RESTART here, even if the data direction has not changed
404 	 *	 from the previous CHAINing call.  This we force the RESTART.
405 	 *	 (A new START is issued automatically by the controller in
406 	 *	 the other nominal cases such as a data direction change or
407 	 *	 a previous STOP was issued).
408 	 *
409 	 * If this will be the last byte read we must also issue the STOP
410 	 * at the end of the read.
411 	 */
412 	if (rcount) {
413 		last = IG4_DATA_RESTART | IG4_DATA_COMMAND_RD;
414 		if (rcount == 1 &&
415 		    (op & (SMB_TRANS_NOSTOP | SMB_TRANS_NOCNT)) ==
416 		    SMB_TRANS_NOCNT) {
417 			last |= IG4_DATA_STOP;
418 		}
419 		reg_write(sc, IG4_REG_DATA_CMD, last);
420 		last = IG4_DATA_COMMAND_RD;
421 	}
422 
423 	/*
424 	 * Bulk read (i2c) and count field handling (smbus)
425 	 */
426 	while (rcount) {
427 		/*
428 		 * Maintain a pipeline by queueing the allowance for the next
429 		 * read before waiting for the current read.
430 		 */
431 		if (rcount > 1) {
432 			if (op & SMB_TRANS_NOCNT)
433 				last = (rcount == 2) ? IG4_DATA_STOP : 0;
434 			else
435 				last = 0;
436 			reg_write(sc, IG4_REG_DATA_CMD, IG4_DATA_COMMAND_RD |
437 							last);
438 		}
439 		error = wait_status(sc, IG4_STATUS_RX_NOTEMPTY);
440 		if (error) {
441 			if ((op & SMB_TRANS_NOREPORT) == 0) {
442 				device_printf(sc->dev,
443 					      "rx timeout addr 0x%02x\n",
444 					      sc->last_slave);
445 			}
446 			goto done;
447 		}
448 		last = data_read(sc);
449 
450 		if (op & SMB_TRANS_NOCNT) {
451 			*rbuf = (u_char)last;
452 			++rbuf;
453 			--rcount;
454 			if (actualp)
455 				++*actualp;
456 		} else {
457 			/*
458 			 * Handle count field (smbus), which is not part of
459 			 * the rcount'ed buffer.  The first read data in a
460 			 * bulk transfer is the count.
461 			 *
462 			 * XXX if rcount is loaded as 0 how do I generate a
463 			 *     STOP now without issuing another RD or WR?
464 			 */
465 			if (rcount > (u_char)last)
466 				rcount = (u_char)last;
467 			op |= SMB_TRANS_NOCNT;
468 		}
469 	}
470 	error = 0;
471 done:
472 	/* XXX wait for xmit buffer to become empty */
473 	last = reg_read(sc, IG4_REG_TX_ABRT_SOURCE);
474 
475 	return error;
476 }
477 
478 /*
479  *				SMBUS API FUNCTIONS
480  *
481  * Called from ig4iic_pci_attach/detach()
482  */
483 int
484 ig4iic_attach(ig4iic_softc_t *sc)
485 {
486 	int error;
487 	uint32_t v;
488 
489 	lockmgr(&sc->lk, LK_EXCLUSIVE);
490 
491 	v = reg_read(sc, IG4_REG_COMP_TYPE);
492 	kprintf("type %08x", v);
493 	v = reg_read(sc, IG4_REG_COMP_PARAM1);
494 	kprintf(" params %08x", v);
495 	v = reg_read(sc, IG4_REG_GENERAL);
496 	kprintf(" general %08x", v);
497 	if ((v & IG4_GENERAL_SWMODE) == 0) {
498 		v |= IG4_GENERAL_SWMODE;
499 		reg_write(sc, IG4_REG_GENERAL, v);
500 		v = reg_read(sc, IG4_REG_GENERAL);
501 		kprintf(" (updated %08x)", v);
502 	}
503 
504 	v = reg_read(sc, IG4_REG_SW_LTR_VALUE);
505 	kprintf(" swltr %08x", v);
506 	v = reg_read(sc, IG4_REG_AUTO_LTR_VALUE);
507 	kprintf(" autoltr %08x", v);
508 
509 	v = reg_read(sc, IG4_REG_COMP_VER);
510 	kprintf(" version %08x\n", v);
511 	if (v != IG4_COMP_VER) {
512 		error = ENXIO;
513 		goto done;
514 	}
515 #if 1
516 	v = reg_read(sc, IG4_REG_SS_SCL_HCNT);
517 	kprintf("SS_SCL_HCNT=%08x", v);
518 	v = reg_read(sc, IG4_REG_SS_SCL_LCNT);
519 	kprintf(" LCNT=%08x", v);
520 	v = reg_read(sc, IG4_REG_FS_SCL_HCNT);
521 	kprintf(" FS_SCL_HCNT=%08x", v);
522 	v = reg_read(sc, IG4_REG_FS_SCL_LCNT);
523 	kprintf(" LCNT=%08x\n", v);
524 	v = reg_read(sc, IG4_REG_SDA_HOLD);
525 	kprintf("HOLD        %08x\n", v);
526 
527 	v = reg_read(sc, IG4_REG_SS_SCL_HCNT);
528 	reg_write(sc, IG4_REG_FS_SCL_HCNT, v);
529 	v = reg_read(sc, IG4_REG_SS_SCL_LCNT);
530 	reg_write(sc, IG4_REG_FS_SCL_LCNT, v);
531 #endif
532 	/*
533 	 * Program based on a 25000 Hz clock.  This is a bit of a
534 	 * hack (obviously).  The defaults are 400 and 470 for standard
535 	 * and 60 and 130 for fast.  The defaults for standard fail
536 	 * utterly (presumably cause an abort) because the clock time
537 	 * is ~18.8ms by default.  This brings it down to ~4ms (for now).
538 	 */
539 	reg_write(sc, IG4_REG_SS_SCL_HCNT, 100);
540 	reg_write(sc, IG4_REG_SS_SCL_LCNT, 125);
541 	reg_write(sc, IG4_REG_FS_SCL_HCNT, 100);
542 	reg_write(sc, IG4_REG_FS_SCL_LCNT, 125);
543 
544 	/*
545 	 * Use a threshold of 1 so we get interrupted on each character,
546 	 * allowing us to use lksleep() in our poll code.  Not perfect
547 	 * but this is better than using DELAY() for receiving data.
548 	 */
549 	reg_write(sc, IG4_REG_RX_TL, 1);
550 
551 	reg_write(sc, IG4_REG_CTL,
552 		  IG4_CTL_MASTER |
553 		  IG4_CTL_SLAVE_DISABLE |
554 		  IG4_CTL_RESTARTEN |
555 		  IG4_CTL_SPEED_STD);
556 	/*
557 	 * When ig4 is attached via ACPI, (child) devices should access the
558 	 * smbus via I2cSerialBus ACPI resources instead.
559 	 */
560 	if (strcmp("acpi", device_get_name(device_get_parent(sc->dev))) != 0) {
561 		sc->smb = device_add_child(sc->dev, "smbus", -1);
562 		if (sc->smb == NULL) {
563 			device_printf(sc->dev, "smbus driver not found\n");
564 			error = ENXIO;
565 			goto done;
566 		}
567 	}
568 
569 	sc->acpismb = device_add_child(sc->dev, "smbacpi", -1);
570 	if (sc->acpismb == NULL) {
571 		device_printf(sc->dev, "smbacpi driver not found\n");
572 		if (sc->smb == NULL) {
573 			error = ENXIO;
574 			goto done;
575 		}
576 	}
577 
578 #if 0
579 	/*
580 	 * Don't do this, it blows up the PCI config
581 	 */
582 	reg_write(sc, IG4_REG_RESETS, IG4_RESETS_ASSERT);
583 	reg_write(sc, IG4_REG_RESETS, IG4_RESETS_DEASSERT);
584 #endif
585 
586 	/*
587 	 * Interrupt on STOP detect or receive character ready
588 	 */
589 	if (set_controller(sc, 0))
590 		device_printf(sc->dev, "controller error during attach-1\n");
591 	if (set_controller(sc, IG4_I2C_ENABLE))
592 		device_printf(sc->dev, "controller error during attach-2\n");
593 	error = bus_setup_intr(sc->dev, sc->intr_res, 0,
594 			       ig4iic_intr, sc, &sc->intr_handle, NULL);
595 	if (error) {
596 		device_printf(sc->dev,
597 			      "Unable to setup irq: error %d\n", error);
598 		goto done;
599 	}
600 
601 	/* Attach us to the smbus */
602 	lockmgr(&sc->lk, LK_RELEASE);
603 	error = bus_generic_attach(sc->dev);
604 	lockmgr(&sc->lk, LK_EXCLUSIVE);
605 	if (error) {
606 		device_printf(sc->dev,
607 			      "failed to attach child: error %d\n", error);
608 		goto done;
609 	}
610 	sc->generic_attached = 1;
611 
612 done:
613 	lockmgr(&sc->lk, LK_RELEASE);
614 	return error;
615 }
616 
617 int
618 ig4iic_detach(ig4iic_softc_t *sc)
619 {
620 	int error;
621 
622 	lockmgr(&sc->lk, LK_EXCLUSIVE);
623 
624 	reg_write(sc, IG4_REG_INTR_MASK, 0);
625 	set_controller(sc, 0);
626 
627 	if (sc->generic_attached) {
628 		error = bus_generic_detach(sc->dev);
629 		if (error)
630 			goto done;
631 		sc->generic_attached = 0;
632 	}
633 	if (sc->smb) {
634 		device_delete_child(sc->dev, sc->smb);
635 		sc->smb = NULL;
636 	}
637 	if (sc->acpismb) {
638 		device_delete_child(sc->dev, sc->acpismb);
639 		sc->acpismb = NULL;
640 	}
641 	if (sc->intr_handle) {
642 		bus_teardown_intr(sc->dev, sc->intr_res, sc->intr_handle);
643 		sc->intr_handle = NULL;
644 	}
645 
646 	error = 0;
647 done:
648 	lockmgr(&sc->lk, LK_RELEASE);
649 	return error;
650 }
651 
652 int
653 ig4iic_smb_callback(device_t dev, int index, void *data)
654 {
655 	ig4iic_softc_t *sc = device_get_softc(dev);
656 	int error;
657 
658 	lockmgr(&sc->lk, LK_EXCLUSIVE);
659 
660 	switch (index) {
661 	case SMB_REQUEST_BUS:
662 		error = 0;
663 		break;
664 	case SMB_RELEASE_BUS:
665 		error = 0;
666 		break;
667 	default:
668 		error = SMB_EABORT;
669 		break;
670 	}
671 
672 	lockmgr(&sc->lk, LK_RELEASE);
673 
674 	return error;
675 }
676 
677 /*
678  * Quick command.  i.e. START + cmd + R/W + STOP and no data.  It is
679  * unclear to me how I could implement this with the intel i2c controller
680  * because the controler sends STARTs and STOPs automatically with data.
681  */
682 int
683 ig4iic_smb_quick(device_t dev, u_char slave, int how)
684 {
685 	ig4iic_softc_t *sc = device_get_softc(dev);
686 	int error;
687 
688 	lockmgr(&sc->lk, LK_EXCLUSIVE);
689 
690 	switch (how) {
691 	case SMB_QREAD:
692 		error = SMB_ENOTSUPP;
693 		break;
694 	case SMB_QWRITE:
695 		error = SMB_ENOTSUPP;
696 		break;
697 	default:
698 		error = SMB_ENOTSUPP;
699 		break;
700 	}
701 	lockmgr(&sc->lk, LK_RELEASE);
702 
703 	return error;
704 }
705 
706 /*
707  * Incremental send byte without stop (?).  It is unclear why the slave
708  * address is specified if this presumably is used in combination with
709  * ig4iic_smb_quick().
710  *
711  * (Also, how would this work anyway?  Issue the last byte with writeb()?)
712  */
713 int
714 ig4iic_smb_sendb(device_t dev, u_char slave, char byte)
715 {
716 	ig4iic_softc_t *sc = device_get_softc(dev);
717 	uint32_t cmd;
718 	int error;
719 
720 	lockmgr(&sc->lk, LK_EXCLUSIVE);
721 
722 	set_slave_addr(sc, slave, 0);
723 	cmd = byte;
724 	if (wait_status(sc, IG4_STATUS_TX_NOTFULL) == 0) {
725 		reg_write(sc, IG4_REG_DATA_CMD, cmd);
726 		error = 0;
727 	} else {
728 		error = SMB_ETIMEOUT;
729 	}
730 
731 	lockmgr(&sc->lk, LK_RELEASE);
732 	return error;
733 }
734 
735 /*
736  * Incremental receive byte without stop (?).  It is unclear why the slave
737  * address is specified if this presumably is used in combination with
738  * ig4iic_smb_quick().
739  */
740 int
741 ig4iic_smb_recvb(device_t dev, u_char slave, char *byte)
742 {
743 	ig4iic_softc_t *sc = device_get_softc(dev);
744 	int error;
745 
746 	lockmgr(&sc->lk, LK_EXCLUSIVE);
747 
748 	set_slave_addr(sc, slave, 0);
749 	reg_write(sc, IG4_REG_DATA_CMD, IG4_DATA_COMMAND_RD);
750 	if (wait_status(sc, IG4_STATUS_RX_NOTEMPTY) == 0) {
751 		*byte = data_read(sc);
752 		error = 0;
753 	} else {
754 		*byte = 0;
755 		error = SMB_ETIMEOUT;
756 	}
757 
758 	lockmgr(&sc->lk, LK_RELEASE);
759 	return error;
760 }
761 
762 /*
763  * Write command and single byte in transaction.
764  */
765 int
766 ig4iic_smb_writeb(device_t dev, u_char slave, char cmd, char byte)
767 {
768 	ig4iic_softc_t *sc = device_get_softc(dev);
769 	int error;
770 
771 	lockmgr(&sc->lk, LK_EXCLUSIVE);
772 
773 	set_slave_addr(sc, slave, 0);
774 	error = smb_transaction(sc, cmd, SMB_TRANS_NOCNT,
775 				&byte, 1, NULL, 0, NULL);
776 
777 	lockmgr(&sc->lk, LK_RELEASE);
778 	return error;
779 }
780 
781 /*
782  * Write command and single word in transaction.
783  */
784 int
785 ig4iic_smb_writew(device_t dev, u_char slave, char cmd, short word)
786 {
787 	ig4iic_softc_t *sc = device_get_softc(dev);
788 	char buf[2];
789 	int error;
790 
791 	lockmgr(&sc->lk, LK_EXCLUSIVE);
792 
793 	set_slave_addr(sc, slave, 0);
794 	buf[0] = word & 0xFF;
795 	buf[1] = word >> 8;
796 	error = smb_transaction(sc, cmd, SMB_TRANS_NOCNT,
797 				buf, 2, NULL, 0, NULL);
798 
799 	lockmgr(&sc->lk, LK_RELEASE);
800 	return error;
801 }
802 
803 /*
804  * write command and read single byte in transaction.
805  */
806 int
807 ig4iic_smb_readb(device_t dev, u_char slave, char cmd, char *byte)
808 {
809 	ig4iic_softc_t *sc = device_get_softc(dev);
810 	int error;
811 
812 	lockmgr(&sc->lk, LK_EXCLUSIVE);
813 
814 	set_slave_addr(sc, slave, 0);
815 	error = smb_transaction(sc, cmd, SMB_TRANS_NOCNT,
816 				NULL, 0, byte, 1, NULL);
817 
818 	lockmgr(&sc->lk, LK_RELEASE);
819 	return error;
820 }
821 
822 /*
823  * write command and read word in transaction.
824  */
825 int
826 ig4iic_smb_readw(device_t dev, u_char slave, char cmd, short *word)
827 {
828 	ig4iic_softc_t *sc = device_get_softc(dev);
829 	char buf[2];
830 	int error;
831 
832 	lockmgr(&sc->lk, LK_EXCLUSIVE);
833 
834 	set_slave_addr(sc, slave, 0);
835 	if ((error = smb_transaction(sc, cmd, SMB_TRANS_NOCNT,
836 				     NULL, 0, buf, 2, NULL)) == 0) {
837 		*word = (u_char)buf[0] | ((u_char)buf[1] << 8);
838 	}
839 
840 	lockmgr(&sc->lk, LK_RELEASE);
841 	return error;
842 }
843 
844 /*
845  * write command and word and read word in transaction
846  */
847 int
848 ig4iic_smb_pcall(device_t dev, u_char slave, char cmd,
849 		 short sdata, short *rdata)
850 {
851 	ig4iic_softc_t *sc = device_get_softc(dev);
852 	char rbuf[2];
853 	char wbuf[2];
854 	int error;
855 
856 	lockmgr(&sc->lk, LK_EXCLUSIVE);
857 
858 	set_slave_addr(sc, slave, 0);
859 	wbuf[0] = sdata & 0xFF;
860 	wbuf[1] = sdata >> 8;
861 	if ((error = smb_transaction(sc, cmd, SMB_TRANS_NOCNT,
862 				     wbuf, 2, rbuf, 2, NULL)) == 0) {
863 		*rdata = (u_char)rbuf[0] | ((u_char)rbuf[1] << 8);
864 	}
865 
866 	lockmgr(&sc->lk, LK_RELEASE);
867 	return error;
868 }
869 
870 int
871 ig4iic_smb_bwrite(device_t dev, u_char slave, char cmd,
872 		  u_char wcount, char *buf)
873 {
874 	ig4iic_softc_t *sc = device_get_softc(dev);
875 	int error;
876 
877 	lockmgr(&sc->lk, LK_EXCLUSIVE);
878 
879 	set_slave_addr(sc, slave, 0);
880 	error = smb_transaction(sc, cmd, 0,
881 				buf, wcount, NULL, 0, NULL);
882 
883 	lockmgr(&sc->lk, LK_RELEASE);
884 	return error;
885 }
886 
887 int
888 ig4iic_smb_bread(device_t dev, u_char slave, char cmd,
889 		 u_char *countp_char, char *buf)
890 {
891 	ig4iic_softc_t *sc = device_get_softc(dev);
892 	int rcount = *countp_char;
893 	int error;
894 
895 	lockmgr(&sc->lk, LK_EXCLUSIVE);
896 
897 	set_slave_addr(sc, slave, 0);
898 	error = smb_transaction(sc, cmd, 0,
899 				NULL, 0, buf, rcount, &rcount);
900 	*countp_char = rcount;
901 
902 	lockmgr(&sc->lk, LK_RELEASE);
903 	return error;
904 }
905 
906 int
907 ig4iic_smb_trans(device_t dev, int slave, char cmd, int op,
908 		 char *wbuf, int wcount, char *rbuf, int rcount,
909 		 int *actualp)
910 {
911 	ig4iic_softc_t *sc = device_get_softc(dev);
912 	int error;
913 
914 	lockmgr(&sc->lk, LK_EXCLUSIVE);
915 
916 	set_slave_addr(sc, slave, op);
917 	error = smb_transaction(sc, cmd, op,
918 				wbuf, wcount, rbuf, rcount, actualp);
919 
920 	lockmgr(&sc->lk, LK_RELEASE);
921 	return error;
922 }
923 
924 /*
925  * Interrupt Operation
926  */
927 static
928 void
929 ig4iic_intr(void *cookie)
930 {
931 	ig4iic_softc_t *sc = cookie;
932 	uint32_t status;
933 
934 	lockmgr(&sc->lk, LK_EXCLUSIVE);
935 /*	reg_write(sc, IG4_REG_INTR_MASK, IG4_INTR_STOP_DET);*/
936 	reg_read(sc, IG4_REG_CLR_INTR);
937 	status = reg_read(sc, IG4_REG_I2C_STA);
938 	while (status & IG4_STATUS_RX_NOTEMPTY) {
939 		sc->rbuf[sc->rnext & IG4_RBUFMASK] =
940 		    (uint8_t)reg_read(sc, IG4_REG_DATA_CMD);
941 		++sc->rnext;
942 		status = reg_read(sc, IG4_REG_I2C_STA);
943 	}
944 	wakeup(sc);
945 	lockmgr(&sc->lk, LK_RELEASE);
946 }
947 
948 #define REGDUMP(sc, reg)	\
949 	device_printf(sc->dev, "  %-23s %08x\n", #reg, reg_read(sc, reg))
950 
951 static
952 void
953 ig4iic_dump(ig4iic_softc_t *sc)
954 {
955 	device_printf(sc->dev, "ig4iic register dump:\n");
956 	REGDUMP(sc, IG4_REG_CTL);
957 	REGDUMP(sc, IG4_REG_TAR_ADD);
958 	REGDUMP(sc, IG4_REG_SS_SCL_HCNT);
959 	REGDUMP(sc, IG4_REG_SS_SCL_LCNT);
960 	REGDUMP(sc, IG4_REG_FS_SCL_HCNT);
961 	REGDUMP(sc, IG4_REG_FS_SCL_LCNT);
962 	REGDUMP(sc, IG4_REG_INTR_STAT);
963 	REGDUMP(sc, IG4_REG_INTR_MASK);
964 	REGDUMP(sc, IG4_REG_RAW_INTR_STAT);
965 	REGDUMP(sc, IG4_REG_RX_TL);
966 	REGDUMP(sc, IG4_REG_TX_TL);
967 	REGDUMP(sc, IG4_REG_I2C_EN);
968 	REGDUMP(sc, IG4_REG_I2C_STA);
969 	REGDUMP(sc, IG4_REG_TXFLR);
970 	REGDUMP(sc, IG4_REG_RXFLR);
971 	REGDUMP(sc, IG4_REG_SDA_HOLD);
972 	REGDUMP(sc, IG4_REG_TX_ABRT_SOURCE);
973 	REGDUMP(sc, IG4_REG_SLV_DATA_NACK);
974 	REGDUMP(sc, IG4_REG_DMA_CTRL);
975 	REGDUMP(sc, IG4_REG_DMA_TDLR);
976 	REGDUMP(sc, IG4_REG_DMA_RDLR);
977 	REGDUMP(sc, IG4_REG_SDA_SETUP);
978 	REGDUMP(sc, IG4_REG_ENABLE_STATUS);
979 	REGDUMP(sc, IG4_REG_COMP_PARAM1);
980 	REGDUMP(sc, IG4_REG_COMP_VER);
981 	REGDUMP(sc, IG4_REG_COMP_TYPE);
982 	REGDUMP(sc, IG4_REG_CLK_PARMS);
983 	REGDUMP(sc, IG4_REG_RESETS);
984 	REGDUMP(sc, IG4_REG_GENERAL);
985 	REGDUMP(sc, IG4_REG_SW_LTR_VALUE);
986 	REGDUMP(sc, IG4_REG_AUTO_LTR_VALUE);
987 }
988 #undef REGDUMP
989 
990 DRIVER_MODULE(smbus, ig4iic, smbus_driver, smbus_devclass, NULL, NULL);
991