xref: /netbsd-src/sys/arch/x86/pci/ichlpcib.c (revision 7fa608457b817eca6e0977b37f758ae064f3c99c)
1 /*	$NetBSD: ichlpcib.c,v 1.4 2007/09/03 03:35:00 xtraeme Exp $	*/
2 
3 /*-
4  * Copyright (c) 2004 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Minoura Makoto and Matthew R. Green.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Intel I/O Controller Hub (ICHn) LPC Interface Bridge driver
41  *
42  *  LPC Interface Bridge is basically a pcib (PCI-ISA Bridge), but has
43  *  some power management and monitoring functions.
44  *  Currently we support the watchdog timer, SpeedStep (on some systems)
45  *  and the power management timer.
46  */
47 
48 #include <sys/cdefs.h>
49 __KERNEL_RCSID(0, "$NetBSD: ichlpcib.c,v 1.4 2007/09/03 03:35:00 xtraeme Exp $");
50 
51 #include <sys/types.h>
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/device.h>
55 #include <sys/sysctl.h>
56 #include <machine/bus.h>
57 
58 #include <dev/pci/pcivar.h>
59 #include <dev/pci/pcireg.h>
60 #include <dev/pci/pcidevs.h>
61 
62 #include <dev/sysmon/sysmonvar.h>
63 
64 #include <dev/ic/i82801lpcreg.h>
65 #include <dev/ic/acpipmtimer.h>
66 
67 struct lpcib_softc {
68 	/* Device object. */
69 	struct device		sc_dev;
70 
71 	pci_chipset_tag_t	sc_pc;
72 	pcitag_t		sc_pcitag;
73 
74 	/* Watchdog variables. */
75 	struct sysmon_wdog	sc_smw;
76 	bus_space_tag_t		sc_iot;
77 	bus_space_handle_t	sc_ioh;
78 
79 	/* Power management */
80 	void			*sc_powerhook;
81 	struct pci_conf_state	sc_pciconf;
82 	pcireg_t		sc_pirq[8];
83 };
84 
85 static int lpcibmatch(struct device *, struct cfdata *, void *);
86 static void lpcibattach(struct device *, struct device *, void *);
87 static void lpcib_powerhook(int, void *);
88 
89 static void pmtimer_configure(struct lpcib_softc *, struct pci_attach_args *);
90 
91 static void tcotimer_configure(struct lpcib_softc *, struct pci_attach_args *);
92 static int tcotimer_setmode(struct sysmon_wdog *);
93 static int tcotimer_tickle(struct sysmon_wdog *);
94 static void tcotimer_stop(struct lpcib_softc *);
95 static void tcotimer_start(struct lpcib_softc *);
96 static void tcotimer_status_reset(struct lpcib_softc *);
97 static int  tcotimer_disable_noreboot(struct lpcib_softc *, bus_space_tag_t,
98 				      bus_space_handle_t);
99 
100 static void speedstep_configure(struct lpcib_softc *, struct pci_attach_args *);
101 static int speedstep_sysctl_helper(SYSCTLFN_ARGS);
102 
103 struct lpcib_softc *speedstep_cookie;	/* XXX */
104 static int lpcib_ich6 = 0;
105 
106 /* Defined in arch/.../pci/pcib.c. */
107 extern void pcibattach(struct device *, struct device *, void *);
108 
109 CFATTACH_DECL(ichlpcib, sizeof(struct lpcib_softc),
110     lpcibmatch, lpcibattach, NULL, NULL);
111 
112 /*
113  * Autoconf callbacks.
114  */
115 static int
116 lpcibmatch(struct device *parent, struct cfdata *match, void *aux)
117 {
118 	struct pci_attach_args *pa = aux;
119 
120 	/* We are ISA bridge, of course */
121 	if (PCI_CLASS(pa->pa_class) != PCI_CLASS_BRIDGE ||
122 	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_BRIDGE_ISA)
123 		return 0;
124 
125 	/* Matches only Intel ICH */
126 	if (PCI_VENDOR(pa->pa_id) == PCI_VENDOR_INTEL) {
127 		switch (PCI_PRODUCT(pa->pa_id)) {
128 		case PCI_PRODUCT_INTEL_82801AA_LPC:	/* ICH */
129 		case PCI_PRODUCT_INTEL_82801AB_LPC:	/* ICH0 */
130 		case PCI_PRODUCT_INTEL_82801BA_LPC:	/* ICH2 */
131 		case PCI_PRODUCT_INTEL_82801BAM_LPC:	/* ICH2-M */
132 		case PCI_PRODUCT_INTEL_82801CA_LPC:	/* ICH3-S */
133 		case PCI_PRODUCT_INTEL_82801CAM_LPC:	/* ICH3-M */
134 		case PCI_PRODUCT_INTEL_82801DB_LPC:	/* ICH4 */
135 		case PCI_PRODUCT_INTEL_82801DB_ISA:	/* ICH4-M */
136 		case PCI_PRODUCT_INTEL_82801EB_LPC:	/* ICH5 */
137 			return 10;
138 		case PCI_PRODUCT_INTEL_82801FB_LPC:	/* ICH6 */
139 		case PCI_PRODUCT_INTEL_82801FBM_LPC:	/* ICH6-M */
140 		case PCI_PRODUCT_INTEL_82801G_LPC:	/* ICH7 */
141 		case PCI_PRODUCT_INTEL_82801GBM_LPC:	/* ICH7-M */
142 		case PCI_PRODUCT_INTEL_82801GHM_LPC:	/* ICH7-M DH */
143 		case PCI_PRODUCT_INTEL_82801H_LPC:	/* ICH8 */
144 		case PCI_PRODUCT_INTEL_82801HH_LPC:	/* ICH8 DH */
145 		case PCI_PRODUCT_INTEL_82801HO_LPC:	/* ICH8 DO */
146 		case PCI_PRODUCT_INTEL_82801HBM_LPC:    /* iCH8-M */
147 		case PCI_PRODUCT_INTEL_82801IH_LPC:	/* ICH9 */
148 		case PCI_PRODUCT_INTEL_82801IR_LPC:	/* ICH9-R */
149 		case PCI_PRODUCT_INTEL_82801IB_LPC:	/* ICH9 ? */
150 			lpcib_ich6 = 1;
151 			return 10;	/* prior to pcib */
152 		}
153 	}
154 
155 	return 0;
156 }
157 
158 static void
159 lpcibattach(struct device *parent, struct device *self, void *aux)
160 {
161 	struct pci_attach_args *pa = aux;
162 	struct lpcib_softc *sc = (void*) self;
163 
164 	sc->sc_pc = pa->pa_pc;
165 	sc->sc_pcitag = pa->pa_tag;
166 
167 	pcibattach(parent, self, aux);
168 
169 	/*
170 	 * Part of our I/O registers are used as ACPI PM regs.
171 	 * Since our ACPI subsystem accesses the I/O space directly so far,
172 	 * we do not have to bother bus_space I/O map confliction.
173 	 */
174 	if (pci_mapreg_map(pa, LPCIB_PCI_PMBASE, PCI_MAPREG_TYPE_IO, 0,
175 			   &sc->sc_iot, &sc->sc_ioh, NULL, NULL)) {
176 		aprint_error("%s: can't map power management i/o space",
177 		       sc->sc_dev.dv_xname);
178 		return;
179 	}
180 
181 	/* Set up the power management timer. */
182 	pmtimer_configure(sc, pa);
183 
184 	/* Set up the TCO (watchdog). */
185 	tcotimer_configure(sc, pa);
186 
187 	/* Set up SpeedStep. */
188 	speedstep_configure(sc, pa);
189 
190 	/* Install powerhook */
191 	sc->sc_powerhook = powerhook_establish(sc->sc_dev.dv_xname,
192 	    lpcib_powerhook, sc);
193 	if (sc->sc_powerhook == NULL)
194 		aprint_error("%s: can't establish powerhook\n",
195 		    sc->sc_dev.dv_xname);
196 }
197 
198 static void
199 lpcib_powerhook(int why, void *opaque)
200 {
201 	struct lpcib_softc *sc;
202 	pci_chipset_tag_t pc;
203 	pcitag_t tag;
204 
205 	sc = (struct lpcib_softc *)opaque;
206 	pc = sc->sc_pc;
207 	tag = sc->sc_pcitag;
208 
209 	switch (why) {
210 	case PWR_SUSPEND:
211 		pci_conf_capture(pc, tag, &sc->sc_pciconf);
212 
213 		/* capture PIRQ routing control registers */
214 		sc->sc_pirq[0] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQA_ROUT);
215 		sc->sc_pirq[1] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQB_ROUT);
216 		sc->sc_pirq[2] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQC_ROUT);
217 		sc->sc_pirq[3] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQD_ROUT);
218 		sc->sc_pirq[4] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQE_ROUT);
219 		sc->sc_pirq[5] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQF_ROUT);
220 		sc->sc_pirq[6] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQG_ROUT);
221 		sc->sc_pirq[7] = pci_conf_read(pc, tag, LPCIB_PCI_PIRQH_ROUT);
222 
223 		break;
224 
225 	case PWR_RESUME:
226 		pci_conf_restore(pc, tag, &sc->sc_pciconf);
227 
228 		/* restore PIRQ routing control registers */
229 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQA_ROUT, sc->sc_pirq[0]);
230 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQB_ROUT, sc->sc_pirq[1]);
231 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQC_ROUT, sc->sc_pirq[2]);
232 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQD_ROUT, sc->sc_pirq[3]);
233 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQE_ROUT, sc->sc_pirq[4]);
234 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQF_ROUT, sc->sc_pirq[5]);
235 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQG_ROUT, sc->sc_pirq[6]);
236 		pci_conf_write(pc, tag, LPCIB_PCI_PIRQH_ROUT, sc->sc_pirq[7]);
237 
238 		break;
239 	}
240 }
241 
242 /*
243  * Initialize the power management timer.
244  */
245 static void
246 pmtimer_configure(struct lpcib_softc *sc, struct pci_attach_args *pa)
247 {
248 	pcireg_t control;
249 
250 	/*
251 	 * Check if power management I/O space is enabled and enable the ACPI_EN
252 	 * bit if it's disabled.
253 	 */
254 	control = pci_conf_read(pa->pa_pc, pa->pa_tag, LPCIB_PCI_ACPI_CNTL);
255 	if ((control & LPCIB_PCI_ACPI_CNTL_EN) == 0) {
256 		control |= LPCIB_PCI_ACPI_CNTL_EN;
257 		pci_conf_write(pa->pa_pc, pa->pa_tag, LPCIB_PCI_ACPI_CNTL,
258 		    control);
259 	}
260 
261 	/* Attach our PM timer with the generic acpipmtimer function */
262 	acpipmtimer_attach(&sc->sc_dev, sc->sc_iot, sc->sc_ioh,
263 	    LPCIB_PM1_TMR, 0);
264 }
265 
266 /*
267  * Initialize the watchdog timer.
268  */
269 static void
270 tcotimer_configure(struct lpcib_softc *sc, struct pci_attach_args *pa)
271 {
272 	bus_space_handle_t gcs_memh;
273 	pcireg_t pcireg;
274 	uint32_t ioreg;
275 	unsigned int period;
276 
277 	/*
278 	 * Map the memory space necessary for GCS (General Control
279 	 * and Status Register). This is where the No Reboot (NR) bit
280 	 * lives on ICH6 and newer.
281 	 */
282 	if (lpcib_ich6) {
283 		pcireg = pci_conf_read(pa->pa_pc, pa->pa_tag, LPCIB_RCBA);
284 		pcireg &= 0xffffc000;
285 		if (bus_space_map(pa->pa_memt, pcireg + LPCIB_GCS_OFFSET,
286 		    		  LPCIB_GCS_SIZE, 0, &gcs_memh)) {
287 			aprint_error("%s: can't map GCS memory space; "
288 			    "TCO timer disabled\n", sc->sc_dev.dv_xname);
289 			return;
290 		}
291 	}
292 
293 	/*
294 	 * Clear the No Reboot (NR) bit. If this fails, enabling the TCO_EN bit
295 	 * in the SMI_EN register is the last chance.
296 	 */
297 	if (tcotimer_disable_noreboot(sc, pa->pa_memt, gcs_memh)) {
298 		ioreg = bus_space_read_4(sc->sc_iot, sc->sc_ioh, LPCIB_SMI_EN);
299 		ioreg |= LPCIB_SMI_EN_TCO_EN;
300 		bus_space_write_4(sc->sc_iot, sc->sc_ioh, LPCIB_SMI_EN, ioreg);
301 	}
302 
303 	/* Reset the watchdog status registers. */
304 	tcotimer_status_reset(sc);
305 
306 	/* Explicitly stop the TCO timer. */
307 	tcotimer_stop(sc);
308 
309 	/*
310 	 * Register the driver with the sysmon watchdog framework.
311 	 */
312 	sc->sc_smw.smw_name = sc->sc_dev.dv_xname;
313 	sc->sc_smw.smw_cookie = sc;
314 	sc->sc_smw.smw_setmode = tcotimer_setmode;
315 	sc->sc_smw.smw_tickle = tcotimer_tickle;
316 	if (lpcib_ich6)
317 		period = LPCIB_TCOTIMER2_MAX_TICK;
318 	else
319 		period = LPCIB_TCOTIMER_MAX_TICK;
320 	sc->sc_smw.smw_period = lpcib_tcotimer_tick_to_second(period);
321 
322 	if (sysmon_wdog_register(&sc->sc_smw)) {
323 		aprint_error("%s: unable to register TCO timer"
324 		       "as a sysmon watchdog device.\n",
325 		       sc->sc_dev.dv_xname);
326 		return;
327 	}
328 
329 	aprint_verbose("%s: TCO (watchdog) timer configured.\n",
330 	    sc->sc_dev.dv_xname);
331 }
332 
333 /*
334  * Sysmon watchdog callbacks.
335  */
336 static int
337 tcotimer_setmode(struct sysmon_wdog *smw)
338 {
339 	struct lpcib_softc *sc = smw->smw_cookie;
340 	unsigned int period;
341 	uint16_t ich6period = 0;
342 
343 	if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
344 		/* Stop the TCO timer. */
345 		tcotimer_stop(sc);
346 	} else {
347 		period = lpcib_tcotimer_second_to_tick(smw->smw_period);
348 		/*
349 		 * ICH5 or older are limited to 4s min and 39s max.
350 		 * ICH6 or newer are limited to 2s min and 613s max.
351 		 */
352 		if (!lpcib_ich6) {
353 			if (period < LPCIB_TCOTIMER_MIN_TICK ||
354 			    period > LPCIB_TCOTIMER_MAX_TICK)
355 				return EINVAL;
356 		} else {
357 			if (period < LPCIB_TCOTIMER2_MIN_TICK ||
358 			    period > LPCIB_TCOTIMER2_MAX_TICK)
359 				return EINVAL;
360 		}
361 
362 		/* Stop the TCO timer, */
363 		tcotimer_stop(sc);
364 
365 		/* set the timeout, */
366 		if (lpcib_ich6) {
367 			/* ICH6 or newer */
368 			ich6period = bus_space_read_2(sc->sc_iot, sc->sc_ioh,
369 						      LPCIB_TCO_TMR2);
370 			ich6period &= 0xfc00;
371 			bus_space_write_2(sc->sc_iot, sc->sc_ioh,
372 					  LPCIB_TCO_TMR2, ich6period | period);
373 		} else {
374 			/* ICH5 or older */
375 			period |= bus_space_read_1(sc->sc_iot, sc->sc_ioh,
376 						   LPCIB_TCO_TMR);
377 			period &= 0xc0;
378 			bus_space_write_1(sc->sc_iot, sc->sc_ioh,
379 					  LPCIB_TCO_TMR, period);
380 		}
381 
382 		/* and start/reload the timer. */
383 		tcotimer_start(sc);
384 		tcotimer_tickle(smw);
385 	}
386 
387 	return 0;
388 }
389 
390 static int
391 tcotimer_tickle(struct sysmon_wdog *smw)
392 {
393 	struct lpcib_softc *sc = smw->smw_cookie;
394 
395 	/* any value is allowed */
396 	if (!lpcib_ich6)
397 		bus_space_write_1(sc->sc_iot, sc->sc_ioh, LPCIB_TCO_RLD, 1);
398 	else
399 		bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO_RLD, 1);
400 
401 	return 0;
402 }
403 
404 static void
405 tcotimer_stop(struct lpcib_softc *sc)
406 {
407 	uint16_t ioreg;
408 
409 	ioreg = bus_space_read_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO1_CNT);
410 	ioreg |= LPCIB_TCO1_CNT_TCO_TMR_HLT;
411 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO1_CNT, ioreg);
412 }
413 
414 static void
415 tcotimer_start(struct lpcib_softc *sc)
416 {
417 	uint16_t ioreg;
418 
419 	ioreg = bus_space_read_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO1_CNT);
420 	ioreg &= ~LPCIB_TCO1_CNT_TCO_TMR_HLT;
421 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO1_CNT, ioreg);
422 }
423 
424 static void
425 tcotimer_status_reset(struct lpcib_softc *sc)
426 {
427 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO1_STS,
428 			  LPCIB_TCO1_STS_TIMEOUT);
429 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO2_STS,
430 			  LPCIB_TCO2_STS_BOOT_STS);
431 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, LPCIB_TCO2_STS,
432 			  LPCIB_TCO2_STS_SECONDS_TO_STS);
433 }
434 
435 /*
436  * Clear the No Reboot (NR) bit, this enables reboots when the timer
437  * reaches the timeout for the second time.
438  */
439 static int
440 tcotimer_disable_noreboot(struct lpcib_softc *sc, bus_space_tag_t gcs_memt,
441 			  bus_space_handle_t gcs_memh)
442 {
443 	pcireg_t pcireg;
444 	uint16_t status = 0;
445 
446 	if (!lpcib_ich6) {
447 		pcireg = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
448 				       LPCIB_PCI_GEN_STA);
449 		if (pcireg & LPCIB_PCI_GEN_STA_NO_REBOOT) {
450 			/* TCO timeout reset is disabled; try to enable it */
451 			pcireg &= ~LPCIB_PCI_GEN_STA_NO_REBOOT;
452 			pci_conf_write(sc->sc_pc, sc->sc_pcitag,
453 				       LPCIB_PCI_GEN_STA, pcireg);
454 			if (pcireg & LPCIB_PCI_GEN_STA_NO_REBOOT)
455 				goto error;
456 		}
457 	} else {
458 		status = bus_space_read_4(gcs_memt, gcs_memh, 0);
459 		status &= ~LPCIB_GCS_NO_REBOOT;
460 		bus_space_write_4(gcs_memt, gcs_memh, 0, status);
461 		status = bus_space_read_4(gcs_memt, gcs_memh, 0);
462 		bus_space_unmap(gcs_memt, gcs_memh, LPCIB_GCS_SIZE);
463 		if (status & LPCIB_GCS_NO_REBOOT)
464 			goto error;
465 	}
466 
467 	return 0;
468 error:
469 	aprint_error("%s: TCO timer reboot disabled by hardware; "
470 	    "hope SMBIOS properly handles it.\n", sc->sc_dev.dv_xname);
471 	return EINVAL;
472 }
473 
474 
475 /*
476  * Intel ICH SpeedStep support.
477  */
478 #define SS_READ(sc, reg) \
479 	bus_space_read_1((sc)->sc_iot, (sc)->sc_ioh, (reg))
480 #define SS_WRITE(sc, reg, val) \
481 	bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
482 
483 /*
484  * Linux driver says that SpeedStep on older chipsets cause
485  * lockups on Dell Inspiron 8000 and 8100.
486  */
487 static int
488 speedstep_bad_hb_check(struct pci_attach_args *pa)
489 {
490 
491 	if (PCI_PRODUCT(pa->pa_id) == PCI_PRODUCT_INTEL_82815_FULL_HUB &&
492 	    PCI_REVISION(pa->pa_class) < 5)
493 		return 1;
494 
495 	return 0;
496 }
497 
498 static void
499 speedstep_configure(struct lpcib_softc *sc, struct pci_attach_args *pa)
500 {
501 	const struct sysctlnode	*node, *ssnode;
502 	int rv;
503 
504 	/* Supported on ICH2-M, ICH3-M and ICH4-M.  */
505 	if (PCI_PRODUCT(pa->pa_id) == PCI_PRODUCT_INTEL_82801DB_ISA ||
506 	    PCI_PRODUCT(pa->pa_id) == PCI_PRODUCT_INTEL_82801CAM_LPC ||
507 	    (PCI_PRODUCT(pa->pa_id) == PCI_PRODUCT_INTEL_82801BAM_LPC &&
508 	     pci_find_device(pa, speedstep_bad_hb_check) == 0)) {
509 		uint8_t pmcon;
510 
511 		/* Enable SpeedStep if it isn't already enabled. */
512 		pmcon = pci_conf_read(pa->pa_pc, pa->pa_tag,
513 				      LPCIB_PCI_GEN_PMCON_1);
514 		if ((pmcon & LPCIB_PCI_GEN_PMCON_1_SS_EN) == 0)
515 			pci_conf_write(pa->pa_pc, pa->pa_tag,
516 				       LPCIB_PCI_GEN_PMCON_1,
517 				       pmcon | LPCIB_PCI_GEN_PMCON_1_SS_EN);
518 
519 		/* Put in machdep.speedstep_state (0 for low, 1 for high). */
520 		if ((rv = sysctl_createv(NULL, 0, NULL, &node,
521 		    CTLFLAG_PERMANENT, CTLTYPE_NODE, "machdep", NULL,
522 		    NULL, 0, NULL, 0, CTL_MACHDEP, CTL_EOL)) != 0)
523 			goto err;
524 
525 		/* CTLFLAG_ANYWRITE? kernel option like EST? */
526 		if ((rv = sysctl_createv(NULL, 0, &node, &ssnode,
527 		    CTLFLAG_READWRITE, CTLTYPE_INT, "speedstep_state", NULL,
528 		    speedstep_sysctl_helper, 0, NULL, 0, CTL_CREATE,
529 		    CTL_EOL)) != 0)
530 			goto err;
531 
532 		/* XXX save the sc for IO tag/handle */
533 		speedstep_cookie = sc;
534 		aprint_verbose("%s: SpeedStep enabled\n", sc->sc_dev.dv_xname);
535 	}
536 
537 	return;
538 
539 err:
540 	aprint_normal("%s: sysctl_createv failed (rv = %d)\n", __func__, rv);
541 }
542 
543 /*
544  * get/set the SpeedStep state: 0 == low power, 1 == high power.
545  */
546 static int
547 speedstep_sysctl_helper(SYSCTLFN_ARGS)
548 {
549 	struct sysctlnode	node;
550 	struct lpcib_softc 	*sc = speedstep_cookie;
551 	uint8_t			state, state2;
552 	int			ostate, nstate, s, error = 0;
553 
554 	/*
555 	 * We do the dance with spl's to avoid being at high ipl during
556 	 * sysctl_lookup() which can both copyin and copyout.
557 	 */
558 	s = splserial();
559 	state = SS_READ(sc, LPCIB_PM_SS_CNTL);
560 	splx(s);
561 	if ((state & LPCIB_PM_SS_STATE_LOW) == 0)
562 		ostate = 1;
563 	else
564 		ostate = 0;
565 	nstate = ostate;
566 
567 	node = *rnode;
568 	node.sysctl_data = &nstate;
569 
570 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
571 	if (error || newp == NULL)
572 		goto out;
573 
574 	/* Only two states are available */
575 	if (nstate != 0 && nstate != 1) {
576 		error = EINVAL;
577 		goto out;
578 	}
579 
580 	s = splserial();
581 	state2 = SS_READ(sc, LPCIB_PM_SS_CNTL);
582 	if ((state2 & LPCIB_PM_SS_STATE_LOW) == 0)
583 		ostate = 1;
584 	else
585 		ostate = 0;
586 
587 	if (ostate != nstate) {
588 		uint8_t cntl;
589 
590 		if (nstate == 0)
591 			state2 |= LPCIB_PM_SS_STATE_LOW;
592 		else
593 			state2 &= ~LPCIB_PM_SS_STATE_LOW;
594 
595 		/*
596 		 * Must disable bus master arbitration during the change.
597 		 */
598 		cntl = SS_READ(sc, LPCIB_PM_CTRL);
599 		SS_WRITE(sc, LPCIB_PM_CTRL, cntl | LPCIB_PM_SS_CNTL_ARB_DIS);
600 		SS_WRITE(sc, LPCIB_PM_SS_CNTL, state2);
601 		SS_WRITE(sc, LPCIB_PM_CTRL, cntl);
602 	}
603 	splx(s);
604 out:
605 	return error;
606 }
607