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acpi_ec.c revision 1.51
      1 /*	$NetBSD: acpi_ec.c,v 1.51 2008/02/29 06:35:40 dyoung Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2007 Joerg Sonnenberger <joerg (at) NetBSD.org>.
      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  *
     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  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
     24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * The ACPI Embedded Controller (EC) driver serves two different purposes:
     34  * - read and write access from ASL, e.g. to read battery state
     35  * - notification of ASL of System Control Interrupts.
     36  *
     37  * Access to the EC is serialised by sc_access_mtx and optionally the
     38  * ACPI global mutex.  Both locks are held until the request is fulfilled.
     39  * All access to the softc has to hold sc_mtx to serialise against the GPE
     40  * handler and the callout.  sc_mtx is also used for wakeup conditions.
     41  *
     42  * SCIs are processed in a kernel thread. Handling gets a bit complicated
     43  * by the lock order (sc_mtx must be acquired after sc_access_mtx and the
     44  * ACPI global mutex).
     45  *
     46  * Read and write requests spin around for a short time as many requests
     47  * can be handled instantly by the EC.  During normal processing interrupt
     48  * mode is used exclusively.  At boot and resume time interrupts are not
     49  * working and the handlers just busy loop.
     50  *
     51  * A callout is scheduled to compensate for missing interrupts on some
     52  * hardware.  If the EC doesn't process a request for 5s, it is most likely
     53  * in a wedged state.  No method to reset the EC is currently known.
     54  *
     55  * Special care has to be taken to not poll the EC in a busy loop without
     56  * delay.  This can prevent processing of Power Button events. At least some
     57  * Lenovo Thinkpads seem to be implement the Power Button Override in the EC
     58  * and the only option to recover on those models is to cut off all power.
     59  */
     60 
     61 #include <sys/cdefs.h>
     62 __KERNEL_RCSID(0, "$NetBSD: acpi_ec.c,v 1.51 2008/02/29 06:35:40 dyoung Exp $");
     63 
     64 #include <sys/param.h>
     65 #include <sys/systm.h>
     66 #include <sys/condvar.h>
     67 #include <sys/device.h>
     68 #include <sys/kernel.h>
     69 #include <sys/kthread.h>
     70 #include <sys/mutex.h>
     71 
     72 #include <sys/bus.h>
     73 
     74 #include <dev/acpi/acpivar.h>
     75 #include <dev/acpi/acpi_ecvar.h>
     76 
     77 /* Maximum time to wait for global ACPI lock in ms */
     78 #define	EC_LOCK_TIMEOUT		5
     79 
     80 /* Maximum time to poll for completion of a command  in ms */
     81 #define	EC_POLL_TIMEOUT		5
     82 
     83 /* Maximum time to give a single EC command in s */
     84 #define EC_CMD_TIMEOUT		10
     85 
     86 /* From ACPI 3.0b, chapter 12.3 */
     87 #define EC_COMMAND_READ		0x80
     88 #define	EC_COMMAND_WRITE	0x81
     89 #define	EC_COMMAND_BURST_EN	0x82
     90 #define	EC_COMMAND_BURST_DIS	0x83
     91 #define	EC_COMMAND_QUERY	0x84
     92 
     93 /* From ACPI 3.0b, chapter 12.2.1 */
     94 #define	EC_STATUS_OBF		0x01
     95 #define	EC_STATUS_IBF		0x02
     96 #define	EC_STATUS_CMD		0x08
     97 #define	EC_STATUS_BURST		0x10
     98 #define	EC_STATUS_SCI		0x20
     99 #define	EC_STATUS_SMI		0x40
    100 
    101 static const char *ec_hid[] = {
    102 	"PNP0C09",
    103 	NULL,
    104 };
    105 
    106 enum ec_state_t {
    107 	EC_STATE_QUERY,
    108 	EC_STATE_QUERY_VAL,
    109 	EC_STATE_READ,
    110 	EC_STATE_READ_ADDR,
    111 	EC_STATE_READ_VAL,
    112 	EC_STATE_WRITE,
    113 	EC_STATE_WRITE_ADDR,
    114 	EC_STATE_WRITE_VAL,
    115 	EC_STATE_FREE
    116 };
    117 
    118 struct acpiec_softc {
    119 	ACPI_HANDLE sc_ech;
    120 
    121 	ACPI_HANDLE sc_gpeh;
    122 	UINT8 sc_gpebit;
    123 
    124 	bus_space_tag_t sc_data_st;
    125 	bus_space_handle_t sc_data_sh;
    126 
    127 	bus_space_tag_t sc_csr_st;
    128 	bus_space_handle_t sc_csr_sh;
    129 
    130 	bool sc_need_global_lock;
    131 	UINT32 sc_global_lock;
    132 
    133 	kmutex_t sc_mtx, sc_access_mtx;
    134 	kcondvar_t sc_cv, sc_cv_sci;
    135 	enum ec_state_t sc_state;
    136 	bool sc_got_sci;
    137 	callout_t sc_pseudo_intr;
    138 
    139 	uint8_t sc_cur_addr, sc_cur_val;
    140 };
    141 
    142 static int acpiecdt_match(device_t, struct cfdata *, void *);
    143 static void acpiecdt_attach(device_t, device_t, void *);
    144 
    145 static int acpiec_match(device_t, struct cfdata *, void *);
    146 static void acpiec_attach(device_t, device_t, void *);
    147 
    148 static void acpiec_common_attach(device_t, device_t, ACPI_HANDLE,
    149     bus_addr_t, bus_addr_t, ACPI_HANDLE, uint8_t);
    150 
    151 static bool acpiec_resume(device_t PMF_FN_PROTO);
    152 static bool acpiec_suspend(device_t PMF_FN_PROTO);
    153 
    154 static bool acpiec_parse_gpe_package(device_t, ACPI_HANDLE,
    155     ACPI_HANDLE *, uint8_t *);
    156 
    157 static void acpiec_callout(void *);
    158 static void acpiec_gpe_query(void *);
    159 static UINT32 acpiec_gpe_handler(void *);
    160 static ACPI_STATUS acpiec_space_setup(ACPI_HANDLE, UINT32, void *, void **);
    161 static ACPI_STATUS acpiec_space_handler(UINT32, ACPI_PHYSICAL_ADDRESS,
    162     UINT32, ACPI_INTEGER *, void *, void *);
    163 
    164 static void acpiec_gpe_state_machine(device_t);
    165 
    166 CFATTACH_DECL_NEW(acpiec, sizeof(struct acpiec_softc),
    167     acpiec_match, acpiec_attach, NULL, NULL);
    168 
    169 CFATTACH_DECL_NEW(acpiecdt, sizeof(struct acpiec_softc),
    170     acpiecdt_match, acpiecdt_attach, NULL, NULL);
    171 
    172 static device_t ec_singleton = NULL;
    173 static bool acpiec_cold = false;
    174 
    175 static bool
    176 acpiecdt_find(device_t parent, ACPI_HANDLE *ec_handle,
    177     bus_addr_t *cmd_reg, bus_addr_t *data_reg, uint8_t *gpebit)
    178 {
    179 	ACPI_TABLE_ECDT *ecdt;
    180 	ACPI_STATUS rv;
    181 
    182 	rv = AcpiGetTable(ACPI_SIG_ECDT, 1, (ACPI_TABLE_HEADER **)&ecdt);
    183 	if (ACPI_FAILURE(rv))
    184 		return false;
    185 
    186 	if (ecdt->Control.BitWidth != 8 || ecdt->Data.BitWidth != 8) {
    187 		aprint_error_dev(parent,
    188 		    "ECDT register width invalid (%d/%d)\n",
    189 		    ecdt->Control.BitWidth, ecdt->Data.BitWidth);
    190 		return false;
    191 	}
    192 
    193 	rv = AcpiGetHandle(ACPI_ROOT_OBJECT, ecdt->Id, ec_handle);
    194 	if (ACPI_FAILURE(rv)) {
    195 		aprint_error_dev(parent,
    196 		    "failed to look up EC object %s: %s\n",
    197 		    ecdt->Id, AcpiFormatException(rv));
    198 		return false;
    199 	}
    200 
    201 	*cmd_reg = ecdt->Control.Address;
    202 	*data_reg = ecdt->Data.Address;
    203 	*gpebit = ecdt->Gpe;
    204 
    205 	return true;
    206 }
    207 
    208 static int
    209 acpiecdt_match(device_t parent, struct cfdata *match, void *aux)
    210 {
    211 	ACPI_HANDLE ec_handle;
    212 	bus_addr_t cmd_reg, data_reg;
    213 	uint8_t gpebit;
    214 
    215 	if (acpiecdt_find(parent, &ec_handle, &cmd_reg, &data_reg, &gpebit))
    216 		return 1;
    217 	else
    218 		return 0;
    219 }
    220 
    221 static void
    222 acpiecdt_attach(device_t parent, device_t self, void *aux)
    223 {
    224 	ACPI_HANDLE ec_handle;
    225 	bus_addr_t cmd_reg, data_reg;
    226 	uint8_t gpebit;
    227 
    228 	if (!acpiecdt_find(parent, &ec_handle, &cmd_reg, &data_reg, &gpebit))
    229 		panic("ECDT disappeared");
    230 
    231 	aprint_naive(": ACPI Embedded Controller via ECDT\n");
    232 	aprint_normal(": ACPI Embedded Controller via ECDT\n");
    233 
    234 	acpiec_common_attach(parent, self, ec_handle, cmd_reg, data_reg,
    235 	    NULL, gpebit);
    236 }
    237 
    238 static int
    239 acpiec_match(device_t parent, struct cfdata *match, void *aux)
    240 {
    241 	struct acpi_attach_args *aa = aux;
    242 
    243 	if (aa->aa_node->ad_type != ACPI_TYPE_DEVICE)
    244 		return 0;
    245 
    246 	return acpi_match_hid(aa->aa_node->ad_devinfo, ec_hid);
    247 }
    248 
    249 static void
    250 acpiec_attach(device_t parent, device_t self, void *aux)
    251 {
    252 	struct acpi_attach_args *aa = aux;
    253 	struct acpi_resources ec_res;
    254 	struct acpi_io *io0, *io1;
    255 	ACPI_HANDLE gpe_handle;
    256 	uint8_t gpebit;
    257 	ACPI_STATUS rv;
    258 
    259 	if (ec_singleton != NULL) {
    260 		aprint_naive(": ACPI Embedded Controller (disabled)\n");
    261 		aprint_normal(": ACPI Embedded Controller (disabled)\n");
    262 		if (!pmf_device_register(self, NULL, NULL))
    263 			aprint_error_dev(self, "couldn't establish power handler\n");
    264 		return;
    265 	}
    266 
    267 	aprint_naive(": ACPI Embedded Controller\n");
    268 	aprint_normal(": ACPI Embedded Controller\n");
    269 
    270 	if (!acpiec_parse_gpe_package(self, aa->aa_node->ad_handle,
    271 				      &gpe_handle, &gpebit))
    272 		return;
    273 
    274 	rv = acpi_resource_parse(self, aa->aa_node->ad_handle, "_CRS",
    275 	    &ec_res, &acpi_resource_parse_ops_default);
    276 	if (rv != AE_OK) {
    277 		aprint_error_dev(self, "resource parsing failed: %s\n",
    278 		    AcpiFormatException(rv));
    279 		return;
    280 	}
    281 
    282 	if ((io0 = acpi_res_io(&ec_res, 0)) == NULL) {
    283 		aprint_error_dev(self, "no data register resource\n");
    284 		goto free_res;
    285 	}
    286 	if ((io1 = acpi_res_io(&ec_res, 1)) == NULL) {
    287 		aprint_error_dev(self, "no CSR register resource\n");
    288 		goto free_res;
    289 	}
    290 
    291 	acpiec_common_attach(parent, self, aa->aa_node->ad_handle,
    292 	    io1->ar_base, io0->ar_base, gpe_handle, gpebit);
    293 
    294 free_res:
    295 	acpi_resource_cleanup(&ec_res);
    296 }
    297 
    298 static void
    299 acpiec_common_attach(device_t parent, device_t self,
    300     ACPI_HANDLE ec_handle, bus_addr_t cmd_reg, bus_addr_t data_reg,
    301     ACPI_HANDLE gpe_handle, uint8_t gpebit)
    302 {
    303 	struct acpiec_softc *sc = device_private(self);
    304 	ACPI_STATUS rv;
    305 	ACPI_INTEGER val;
    306 
    307 	sc->sc_ech = ec_handle;
    308 	sc->sc_gpeh = gpe_handle;
    309 	sc->sc_gpebit = gpebit;
    310 
    311 	sc->sc_state = EC_STATE_FREE;
    312 	mutex_init(&sc->sc_mtx, MUTEX_DRIVER, IPL_TTY);
    313 	mutex_init(&sc->sc_access_mtx, MUTEX_DEFAULT, IPL_NONE);
    314 	cv_init(&sc->sc_cv, "eccv");
    315 	cv_init(&sc->sc_cv_sci, "ecsci");
    316 
    317 	if (bus_space_map(sc->sc_data_st, data_reg, 1, 0,
    318 	    &sc->sc_data_sh) != 0) {
    319 		aprint_error_dev(self, "unable to map data register\n");
    320 		return;
    321 	}
    322 
    323 	if (bus_space_map(sc->sc_csr_st, cmd_reg, 1, 0, &sc->sc_csr_sh) != 0) {
    324 		aprint_error_dev(self, "unable to map CSR register\n");
    325 		goto post_data_map;
    326 	}
    327 
    328 	rv = acpi_eval_integer(sc->sc_ech, "_GLK", &val);
    329 	if (rv == AE_OK) {
    330 		sc->sc_need_global_lock = val != 0;
    331 	} else if (rv != AE_NOT_FOUND) {
    332 		aprint_error_dev(self, "unable to evaluate _GLK: %s\n",
    333 		    AcpiFormatException(rv));
    334 		goto post_csr_map;
    335 	} else {
    336 		sc->sc_need_global_lock = false;
    337 	}
    338 	if (sc->sc_need_global_lock)
    339 		aprint_normal_dev(self, "using global ACPI lock\n");
    340 
    341 	callout_init(&sc->sc_pseudo_intr, CALLOUT_MPSAFE);
    342 	callout_setfunc(&sc->sc_pseudo_intr, acpiec_callout, self);
    343 
    344 	rv = AcpiInstallAddressSpaceHandler(sc->sc_ech, ACPI_ADR_SPACE_EC,
    345 	    acpiec_space_handler, acpiec_space_setup, self);
    346 	if (rv != AE_OK) {
    347 		aprint_error_dev(self,
    348 		    "unable to install address space handler: %s\n",
    349 		    AcpiFormatException(rv));
    350 		goto post_csr_map;
    351 	}
    352 
    353 	rv = AcpiInstallGpeHandler(sc->sc_gpeh, sc->sc_gpebit,
    354 	    ACPI_GPE_EDGE_TRIGGERED, acpiec_gpe_handler, self);
    355 	if (rv != AE_OK) {
    356 		aprint_error_dev(self, "unable to install GPE handler: %s\n",
    357 		    AcpiFormatException(rv));
    358 		goto post_csr_map;
    359 	}
    360 
    361 	rv = AcpiSetGpeType(sc->sc_gpeh, sc->sc_gpebit, ACPI_GPE_TYPE_RUNTIME);
    362 	if (rv != AE_OK) {
    363 		aprint_error_dev(self, "unable to set GPE type: %s\n",
    364 		    AcpiFormatException(rv));
    365 		goto post_csr_map;
    366 	}
    367 
    368 	rv = AcpiEnableGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_ISR);
    369 	if (rv != AE_OK) {
    370 		aprint_error_dev(self, "unable to enable GPE: %s\n",
    371 		    AcpiFormatException(rv));
    372 		goto post_csr_map;
    373 	}
    374 
    375 	if (kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, acpiec_gpe_query,
    376 		           self, NULL, "acpiec sci thread")) {
    377 		aprint_error_dev(self, "unable to create query kthread\n");
    378 		goto post_csr_map;
    379 	}
    380 
    381 	ec_singleton = self;
    382 
    383 	if (!pmf_device_register(self, acpiec_suspend, acpiec_resume))
    384 		aprint_error_dev(self, "couldn't establish power handler\n");
    385 
    386 	return;
    387 
    388 post_csr_map:
    389 	(void)AcpiRemoveGpeHandler(sc->sc_gpeh, sc->sc_gpebit,
    390 	    acpiec_gpe_handler);
    391 	(void)AcpiRemoveAddressSpaceHandler(sc->sc_ech,
    392 	    ACPI_ADR_SPACE_EC, acpiec_space_handler);
    393 	bus_space_unmap(sc->sc_csr_st, sc->sc_csr_sh, 1);
    394 post_data_map:
    395 	bus_space_unmap(sc->sc_data_st, sc->sc_data_sh, 1);
    396 }
    397 
    398 static bool
    399 acpiec_suspend(device_t dv PMF_FN_ARGS)
    400 {
    401 	acpiec_cold = true;
    402 
    403 	return true;
    404 }
    405 
    406 static bool
    407 acpiec_resume(device_t dv PMF_FN_ARGS)
    408 {
    409 	acpiec_cold = false;
    410 
    411 	return true;
    412 }
    413 
    414 static bool
    415 acpiec_parse_gpe_package(device_t self, ACPI_HANDLE ec_handle,
    416     ACPI_HANDLE *gpe_handle, uint8_t *gpebit)
    417 {
    418 	ACPI_BUFFER buf;
    419 	ACPI_OBJECT *p, *c;
    420 	ACPI_STATUS rv;
    421 
    422 	rv = acpi_eval_struct(ec_handle, "_GPE", &buf);
    423 	if (rv != AE_OK) {
    424 		aprint_error_dev(self, "unable to evaluate _GPE: %s\n",
    425 		    AcpiFormatException(rv));
    426 		return false;
    427 	}
    428 
    429 	p = buf.Pointer;
    430 
    431 	if (p->Type == ACPI_TYPE_INTEGER) {
    432 		*gpe_handle = NULL;
    433 		*gpebit = p->Integer.Value;
    434 		AcpiOsFree(p);
    435 		return true;
    436 	}
    437 
    438 	if (p->Type != ACPI_TYPE_PACKAGE) {
    439 		aprint_error_dev(self, "_GPE is neither integer nor package\n");
    440 		AcpiOsFree(p);
    441 		return false;
    442 	}
    443 
    444 	if (p->Package.Count != 2) {
    445 		aprint_error_dev(self, "_GPE package does not contain 2 elements\n");
    446 		AcpiOsFree(p);
    447 		return false;
    448 	}
    449 
    450 	c = &p->Package.Elements[0];
    451 	switch (c->Type) {
    452 	case ACPI_TYPE_LOCAL_REFERENCE:
    453 	case ACPI_TYPE_ANY:
    454 		*gpe_handle = c->Reference.Handle;
    455 		break;
    456 	case ACPI_TYPE_STRING:
    457 		/* XXX should be using real scope here */
    458 		rv = AcpiGetHandle(NULL, p->String.Pointer, gpe_handle);
    459 		if (rv != AE_OK) {
    460 			aprint_error_dev(self,
    461 			    "_GPE device reference unresolvable\n");
    462 			AcpiOsFree(p);
    463 			return false;
    464 		}
    465 		break;
    466 	default:
    467 		aprint_error_dev(self, "_GPE device reference incorrect\n");
    468 		AcpiOsFree(p);
    469 		return false;
    470 	}
    471 	c = &p->Package.Elements[1];
    472 	if (c->Type != ACPI_TYPE_INTEGER) {
    473 		aprint_error_dev(self,
    474 		    "_GPE package needs integer as 2nd field\n");
    475 		AcpiOsFree(p);
    476 		return false;
    477 	}
    478 	*gpebit = c->Integer.Value;
    479 	AcpiOsFree(p);
    480 	return true;
    481 }
    482 
    483 static uint8_t
    484 acpiec_read_data(struct acpiec_softc *sc)
    485 {
    486 	return bus_space_read_1(sc->sc_data_st, sc->sc_data_sh, 0);
    487 }
    488 
    489 static void
    490 acpiec_write_data(struct acpiec_softc *sc, uint8_t val)
    491 {
    492 	bus_space_write_1(sc->sc_data_st, sc->sc_data_sh, 0, val);
    493 }
    494 
    495 static uint8_t
    496 acpiec_read_status(struct acpiec_softc *sc)
    497 {
    498 	return bus_space_read_1(sc->sc_csr_st, sc->sc_csr_sh, 0);
    499 }
    500 
    501 static void
    502 acpiec_write_command(struct acpiec_softc *sc, uint8_t cmd)
    503 {
    504 	bus_space_write_1(sc->sc_csr_st, sc->sc_csr_sh, 0, cmd);
    505 }
    506 
    507 static ACPI_STATUS
    508 acpiec_space_setup(ACPI_HANDLE region, UINT32 func, void *arg,
    509     void **region_arg)
    510 {
    511 	if (func == ACPI_REGION_DEACTIVATE)
    512 		*region_arg = NULL;
    513 	else
    514 		*region_arg = arg;
    515 
    516 	return AE_OK;
    517 }
    518 
    519 static void
    520 acpiec_lock(device_t dv)
    521 {
    522 	struct acpiec_softc *sc = device_private(dv);
    523 	ACPI_STATUS rv;
    524 
    525 	mutex_enter(&sc->sc_access_mtx);
    526 
    527 	if (sc->sc_need_global_lock) {
    528 		rv = AcpiAcquireGlobalLock(EC_LOCK_TIMEOUT, &sc->sc_global_lock);
    529 		if (rv != AE_OK) {
    530 			aprint_error_dev(dv, "failed to acquire global lock: %s\n",
    531 			    AcpiFormatException(rv));
    532 			return;
    533 		}
    534 	}
    535 }
    536 
    537 static void
    538 acpiec_unlock(device_t dv)
    539 {
    540 	struct acpiec_softc *sc = device_private(dv);
    541 	ACPI_STATUS rv;
    542 
    543 	if (sc->sc_need_global_lock) {
    544 		rv = AcpiReleaseGlobalLock(sc->sc_global_lock);
    545 		if (rv != AE_OK) {
    546 			aprint_error_dev(dv, "failed to release global lock: %s\n",
    547 			    AcpiFormatException(rv));
    548 		}
    549 	}
    550 	mutex_exit(&sc->sc_access_mtx);
    551 }
    552 
    553 static ACPI_STATUS
    554 acpiec_read(device_t dv, uint8_t addr, uint8_t *val)
    555 {
    556 	struct acpiec_softc *sc = device_private(dv);
    557 	int i, timeo = 1000 * EC_CMD_TIMEOUT;
    558 
    559 	acpiec_lock(dv);
    560 	mutex_enter(&sc->sc_mtx);
    561 
    562 	sc->sc_cur_addr = addr;
    563 	sc->sc_state = EC_STATE_READ;
    564 
    565 	for (i = 0; i < EC_POLL_TIMEOUT; ++i) {
    566 		acpiec_gpe_state_machine(dv);
    567 		if (sc->sc_state == EC_STATE_FREE)
    568 			goto done;
    569 		delay(1);
    570 	}
    571 
    572 	if (cold || acpiec_cold) {
    573 		while (sc->sc_state != EC_STATE_FREE && timeo-- > 0) {
    574 			delay(1000);
    575 			acpiec_gpe_state_machine(dv);
    576 		}
    577 		if (sc->sc_state != EC_STATE_FREE) {
    578 			mutex_exit(&sc->sc_mtx);
    579 			AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_NOT_ISR);
    580 			acpiec_unlock(dv);
    581 			aprint_error_dev(dv, "command timed out, state %d\n",
    582 			    sc->sc_state);
    583 			return AE_ERROR;
    584 		}
    585 	} else while (cv_timedwait(&sc->sc_cv, &sc->sc_mtx, EC_CMD_TIMEOUT * hz)) {
    586 		mutex_exit(&sc->sc_mtx);
    587 		AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_NOT_ISR);
    588 		acpiec_unlock(dv);
    589 		aprint_error_dev(dv, "command takes over %d sec...\n", EC_CMD_TIMEOUT);
    590 		return AE_ERROR;
    591 	}
    592 
    593 done:
    594 	*val = sc->sc_cur_val;
    595 
    596 	mutex_exit(&sc->sc_mtx);
    597 	acpiec_unlock(dv);
    598 	return AE_OK;
    599 }
    600 
    601 static ACPI_STATUS
    602 acpiec_write(device_t dv, uint8_t addr, uint8_t val)
    603 {
    604 	struct acpiec_softc *sc = device_private(dv);
    605 	int i, timeo = 1000 * EC_CMD_TIMEOUT;
    606 
    607 	acpiec_lock(dv);
    608 	mutex_enter(&sc->sc_mtx);
    609 
    610 	sc->sc_cur_addr = addr;
    611 	sc->sc_cur_val = val;
    612 	sc->sc_state = EC_STATE_WRITE;
    613 
    614 	for (i = 0; i < EC_POLL_TIMEOUT; ++i) {
    615 		acpiec_gpe_state_machine(dv);
    616 		if (sc->sc_state == EC_STATE_FREE)
    617 			goto done;
    618 		delay(1);
    619 	}
    620 
    621 	if (cold || acpiec_cold) {
    622 		while (sc->sc_state != EC_STATE_FREE && timeo-- > 0) {
    623 			delay(1000);
    624 			acpiec_gpe_state_machine(dv);
    625 		}
    626 		if (sc->sc_state != EC_STATE_FREE) {
    627 			mutex_exit(&sc->sc_mtx);
    628 			AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_NOT_ISR);
    629 			acpiec_unlock(dv);
    630 			aprint_error_dev(dv, "command timed out, state %d\n",
    631 			    sc->sc_state);
    632 			return AE_ERROR;
    633 		}
    634 	} else while (cv_timedwait(&sc->sc_cv, &sc->sc_mtx, EC_CMD_TIMEOUT * hz)) {
    635 		mutex_exit(&sc->sc_mtx);
    636 		AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_NOT_ISR);
    637 		acpiec_unlock(dv);
    638 		aprint_error_dev(dv, "command takes over %d sec...\n", EC_CMD_TIMEOUT);
    639 		return AE_ERROR;
    640 	}
    641 
    642 done:
    643 	mutex_exit(&sc->sc_mtx);
    644 	acpiec_unlock(dv);
    645 	return AE_OK;
    646 }
    647 
    648 static ACPI_STATUS
    649 acpiec_space_handler(UINT32 func, ACPI_PHYSICAL_ADDRESS paddr,
    650     UINT32 width, ACPI_INTEGER *value, void *arg, void *region_arg)
    651 {
    652 	device_t dv;
    653 	struct acpiec_softc *sc;
    654 	ACPI_STATUS rv;
    655 	uint8_t addr, reg;
    656 	unsigned int i;
    657 
    658 	if (paddr > 0xff || width % 8 != 0 || value == NULL || arg == NULL ||
    659 	    paddr + width / 8 > 0xff)
    660 		return AE_BAD_PARAMETER;
    661 
    662 	addr = paddr;
    663 	dv = arg;
    664 	sc = device_private(dv);
    665 
    666 	rv = AE_OK;
    667 
    668 	switch (func) {
    669 	case ACPI_READ:
    670 		*value = 0;
    671 		for (i = 0; i < width; i += 8, ++addr) {
    672 			rv = acpiec_read(dv, addr, &reg);
    673 			if (rv != AE_OK)
    674 				break;
    675 			*value |= (ACPI_INTEGER)reg << i;
    676 		}
    677 		break;
    678 	case ACPI_WRITE:
    679 		for (i = 0; i < width; i += 8, ++addr) {
    680 			reg = (*value >>i) & 0xff;
    681 			rv = acpiec_write(dv, addr, reg);
    682 			if (rv != AE_OK)
    683 				break;
    684 		}
    685 		break;
    686 	default:
    687 		aprint_error("%s: invalid Address Space function called: %x\n",
    688 		    device_xname(dv), (unsigned int)func);
    689 		return AE_BAD_PARAMETER;
    690 	}
    691 
    692 	return rv;
    693 }
    694 
    695 static void
    696 acpiec_gpe_query(void *arg)
    697 {
    698 	device_t dv = arg;
    699 	struct acpiec_softc *sc = device_private(dv);
    700 	uint8_t reg;
    701 	char qxx[5];
    702 	ACPI_STATUS rv;
    703 	int i;
    704 
    705 loop:
    706 	mutex_enter(&sc->sc_mtx);
    707 
    708 	if (sc->sc_got_sci == false)
    709 		cv_wait(&sc->sc_cv_sci, &sc->sc_mtx);
    710 	mutex_exit(&sc->sc_mtx);
    711 
    712 	acpiec_lock(dv);
    713 	mutex_enter(&sc->sc_mtx);
    714 
    715 	/* The Query command can always be issued, so be defensive here. */
    716 	sc->sc_got_sci = false;
    717 	sc->sc_state = EC_STATE_QUERY;
    718 
    719 	for (i = 0; i < EC_POLL_TIMEOUT; ++i) {
    720 		acpiec_gpe_state_machine(dv);
    721 		if (sc->sc_state == EC_STATE_FREE)
    722 			goto done;
    723 		delay(1);
    724 	}
    725 
    726 	cv_wait(&sc->sc_cv, &sc->sc_mtx);
    727 
    728 done:
    729 	reg = sc->sc_cur_val;
    730 
    731 	mutex_exit(&sc->sc_mtx);
    732 	acpiec_unlock(dv);
    733 
    734 	if (reg == 0)
    735 		goto loop; /* Spurious query result */
    736 
    737 	/*
    738 	 * Evaluate _Qxx to respond to the controller.
    739 	 */
    740 	snprintf(qxx, sizeof(qxx), "_Q%02X", (unsigned int)reg);
    741 	rv = AcpiEvaluateObject(sc->sc_ech, qxx, NULL, NULL);
    742 	if (rv != AE_OK && rv != AE_NOT_FOUND) {
    743 		aprint_error("%s: GPE query method %s failed: %s",
    744 		    device_xname(dv), qxx, AcpiFormatException(rv));
    745 	}
    746 
    747 	goto loop;
    748 }
    749 
    750 static void
    751 acpiec_gpe_state_machine(device_t dv)
    752 {
    753 	struct acpiec_softc *sc = device_private(dv);
    754 	uint8_t reg;
    755 
    756 	reg = acpiec_read_status(sc);
    757 
    758 	if (reg & EC_STATUS_SCI)
    759 		sc->sc_got_sci = true;
    760 
    761 	switch (sc->sc_state) {
    762 	case EC_STATE_QUERY:
    763 		if ((reg & EC_STATUS_IBF) != 0)
    764 			break; /* Nothing of interest here. */
    765 		acpiec_write_command(sc, EC_COMMAND_QUERY);
    766 		sc->sc_state = EC_STATE_QUERY_VAL;
    767 		break;
    768 
    769 	case EC_STATE_QUERY_VAL:
    770 		if ((reg & EC_STATUS_OBF) == 0)
    771 			break; /* Nothing of interest here. */
    772 
    773 		sc->sc_cur_val = acpiec_read_data(sc);
    774 		sc->sc_state = EC_STATE_FREE;
    775 
    776 		cv_signal(&sc->sc_cv);
    777 		break;
    778 
    779 	case EC_STATE_READ:
    780 		if ((reg & EC_STATUS_IBF) != 0)
    781 			break; /* Nothing of interest here. */
    782 
    783 		acpiec_write_command(sc, EC_COMMAND_READ);
    784 		sc->sc_state = EC_STATE_READ_ADDR;
    785 		break;
    786 
    787 	case EC_STATE_READ_ADDR:
    788 		if ((reg & EC_STATUS_IBF) != 0)
    789 			break; /* Nothing of interest here. */
    790 
    791 		acpiec_write_data(sc, sc->sc_cur_addr);
    792 		sc->sc_state = EC_STATE_READ_VAL;
    793 		break;
    794 
    795 	case EC_STATE_READ_VAL:
    796 		if ((reg & EC_STATUS_OBF) == 0)
    797 			break; /* Nothing of interest here. */
    798 		sc->sc_cur_val = acpiec_read_data(sc);
    799 		sc->sc_state = EC_STATE_FREE;
    800 
    801 		cv_signal(&sc->sc_cv);
    802 		break;
    803 
    804 	case EC_STATE_WRITE:
    805 		if ((reg & EC_STATUS_IBF) != 0)
    806 			break; /* Nothing of interest here. */
    807 
    808 		acpiec_write_command(sc, EC_COMMAND_WRITE);
    809 		sc->sc_state = EC_STATE_WRITE_ADDR;
    810 		break;
    811 
    812 	case EC_STATE_WRITE_ADDR:
    813 		if ((reg & EC_STATUS_IBF) != 0)
    814 			break; /* Nothing of interest here. */
    815 		acpiec_write_data(sc, sc->sc_cur_addr);
    816 		sc->sc_state = EC_STATE_WRITE_VAL;
    817 		break;
    818 
    819 	case EC_STATE_WRITE_VAL:
    820 		if ((reg & EC_STATUS_IBF) != 0)
    821 			break; /* Nothing of interest here. */
    822 		sc->sc_state = EC_STATE_FREE;
    823 		cv_signal(&sc->sc_cv);
    824 
    825 		acpiec_write_data(sc, sc->sc_cur_val);
    826 		break;
    827 
    828 	case EC_STATE_FREE:
    829 		if (sc->sc_got_sci)
    830 			cv_signal(&sc->sc_cv_sci);
    831 		break;
    832 	default:
    833 		panic("invalid state");
    834 	}
    835 
    836 	if (sc->sc_state != EC_STATE_FREE)
    837 		callout_schedule(&sc->sc_pseudo_intr, 1);
    838 }
    839 
    840 static void
    841 acpiec_callout(void *arg)
    842 {
    843 	device_t dv = arg;
    844 	struct acpiec_softc *sc = device_private(dv);
    845 
    846 	AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_NOT_ISR);
    847 
    848 	mutex_enter(&sc->sc_mtx);
    849 	acpiec_gpe_state_machine(dv);
    850 	mutex_exit(&sc->sc_mtx);
    851 }
    852 
    853 static UINT32
    854 acpiec_gpe_handler(void *arg)
    855 {
    856 	device_t dv = arg;
    857 	struct acpiec_softc *sc = device_private(dv);
    858 
    859 	AcpiClearGpe(sc->sc_gpeh, sc->sc_gpebit, ACPI_ISR);
    860 
    861 	mutex_enter(&sc->sc_mtx);
    862 	acpiec_gpe_state_machine(dv);
    863 	mutex_exit(&sc->sc_mtx);
    864 
    865 	return 0;
    866 }
    867 
    868 ACPI_STATUS
    869 acpiec_bus_read(device_t dv, u_int addr, ACPI_INTEGER *val, int width)
    870 {
    871 	return acpiec_space_handler(ACPI_READ, addr, width * 8, val, dv, NULL);
    872 }
    873 
    874 ACPI_STATUS
    875 acpiec_bus_write(device_t dv, u_int addr, ACPI_INTEGER val, int width)
    876 {
    877 	return acpiec_space_handler(ACPI_WRITE, addr, width * 8, &val, dv, NULL);
    878 }
    879 
    880 ACPI_HANDLE
    881 acpiec_get_handle(device_t dv)
    882 {
    883 	struct acpiec_softc *sc = device_private(dv);
    884 
    885 	return sc->sc_ech;
    886 }
    887