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viapcib.c revision 1.4
      1 /* $NetBSD: viapcib.c,v 1.4 2006/10/12 01:30:44 christos Exp $ */
      2 /* $FreeBSD: src/sys/pci/viapm.c,v 1.10 2005/05/29 04:42:29 nyan Exp $ */
      3 
      4 /*-
      5  * Copyright (c) 2005, 2006 Jared D. McNeill <jmcneill (at) invisible.ca>
      6  * All rights reserved.
      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  * 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 the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. The name of the author may not be used to endorse or promote products
     17  *    derived from this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR 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
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 /*-
     32  * Copyright (c) 2001 Alcove - Nicolas Souchu
     33  * All rights reserved.
     34  *
     35  * Redistribution and use in source and binary forms, with or without
     36  * modification, are permitted provided that the following conditions
     37  * are met:
     38  * 1. Redistributions of source code must retain the above copyright
     39  *    notice, this list of conditions and the following disclaimer.
     40  * 2. Redistributions in binary form must reproduce the above copyright
     41  *    notice, this list of conditions and the following disclaimer in the
     42  *    documentation and/or other materials provided with the distribution.
     43  *
     44  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     54  * SUCH DAMAGE.
     55  */
     56 
     57 #include <sys/cdefs.h>
     58 __KERNEL_RCSID(0, "$NetBSD: viapcib.c,v 1.4 2006/10/12 01:30:44 christos Exp $");
     59 
     60 #include <sys/types.h>
     61 #include <sys/param.h>
     62 #include <sys/systm.h>
     63 #include <sys/device.h>
     64 #include <sys/proc.h>
     65 
     66 #include <machine/bus.h>
     67 
     68 #include <dev/pci/pcireg.h>
     69 #include <dev/pci/pcivar.h>
     70 #include <dev/pci/pcidevs.h>
     71 
     72 #include <dev/i2c/i2cvar.h>
     73 
     74 #include <i386/pci/viapcibreg.h>
     75 
     76 /*#define VIAPCIB_DEBUG*/
     77 
     78 #ifdef	VIAPCIB_DEBUG
     79 #define	DPRINTF(x)	printf x
     80 #else
     81 #define	DPRINTF(x)
     82 #endif
     83 
     84 struct viapcib_softc {
     85 	struct device	sc_dev;
     86 	bus_space_tag_t	sc_iot;
     87 	bus_space_handle_t sc_ioh;
     88 	struct i2c_controller sc_i2c;
     89 
     90 	int sc_revision;
     91 
     92 	struct simplelock sc_lock;
     93 };
     94 
     95 static int	viapcib_match(struct device *, struct cfdata *, void *);
     96 static void	viapcib_attach(struct device *, struct device *, void *);
     97 
     98 static int	viapcib_clear(struct viapcib_softc *);
     99 static int	viapcib_busy(struct viapcib_softc *);
    100 
    101 #define		viapcib_smbus_read(sc, o) \
    102 	bus_space_read_1((sc)->sc_iot, (sc)->sc_ioh, (o))
    103 #define		viapcib_smbus_write(sc, o, v) \
    104 	bus_space_write_1((sc)->sc_iot, (sc)->sc_ioh, (o), (v))
    105 
    106 #define	VIAPCIB_SMBUS_TIMEOUT	10000
    107 
    108 static int	viapcib_acquire_bus(void *, int);
    109 static void	viapcib_release_bus(void *, int);
    110 static int	viapcib_exec(void *, i2c_op_t, i2c_addr_t, const void *,
    111 			     size_t, void *, size_t, int);
    112 
    113 /* SMBus operations */
    114 static int      viapcib_smbus_quick_write(void *, i2c_addr_t);
    115 static int      viapcib_smbus_quick_read(void *, i2c_addr_t);
    116 static int      viapcib_smbus_send_byte(void *, i2c_addr_t, uint8_t);
    117 static int      viapcib_smbus_receive_byte(void *, i2c_addr_t,
    118                                            uint8_t *);
    119 static int      viapcib_smbus_read_byte(void *, i2c_addr_t, uint8_t,
    120 					int8_t *);
    121 static int      viapcib_smbus_write_byte(void *, i2c_addr_t, uint8_t,
    122 					 int8_t);
    123 static int      viapcib_smbus_read_word(void *, i2c_addr_t, uint8_t,
    124 					int16_t *);
    125 static int      viapcib_smbus_write_word(void *, i2c_addr_t, uint8_t,
    126 					 int16_t);
    127 static int      viapcib_smbus_block_write(void *, i2c_addr_t, uint8_t,
    128 					  int, void *);
    129 static int      viapcib_smbus_block_read(void *, i2c_addr_t, uint8_t,
    130 					 int, void *);
    131 /* XXX Should be moved to smbus layer */
    132 #define	SMB_MAXBLOCKSIZE	32
    133 
    134 /* from arch/i386/pci/pcib.c */
    135 extern void	pcibattach(struct device *, struct device *, void *);
    136 
    137 CFATTACH_DECL(viapcib, sizeof(struct viapcib_softc), viapcib_match,
    138     viapcib_attach, NULL, NULL);
    139 
    140 static int
    141 viapcib_match(struct device *parent __unused, struct cfdata *match __unused,
    142     void *opaque)
    143 {
    144 	struct pci_attach_args *pa;
    145 
    146 	pa = (struct pci_attach_args *)opaque;
    147 
    148 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_VIATECH)
    149 		return 0;
    150 
    151 	switch (PCI_PRODUCT(pa->pa_id)) {
    152 	case PCI_PRODUCT_VIATECH_VT8235:
    153 	case PCI_PRODUCT_VIATECH_VT8237:
    154 		return 2; /* match above generic pcib(4) */
    155 	}
    156 
    157 	return 0;
    158 }
    159 
    160 static void
    161 viapcib_attach(struct device *parent, struct device *self, void *opaque)
    162 {
    163 	struct viapcib_softc *sc;
    164 	struct pci_attach_args *pa;
    165 	pcireg_t addr, val;
    166 
    167 	sc = (struct viapcib_softc *)self;
    168 	pa = (struct pci_attach_args *)opaque;
    169 
    170 	/* XXX Only the 8235 is supported for now */
    171 	sc->sc_iot = pa->pa_iot;
    172 	addr = pci_conf_read(pa->pa_pc, pa->pa_tag, SMB_BASE3);
    173 	addr &= 0xfff0;
    174 	if (bus_space_map(sc->sc_iot, addr, 8, 0, &sc->sc_ioh)) {
    175 		printf(": failed to map SMBus I/O space\n");
    176 		addr = 0;
    177 		goto core_pcib;
    178 	}
    179 
    180 	simple_lock_init(&sc->sc_lock);
    181 
    182 	val = pci_conf_read(pa->pa_pc, pa->pa_tag, SMB_HOST_CONFIG);
    183 	if ((val & 1) == 0) {
    184 		printf(": SMBus is disabled\n");
    185 		addr = 0;
    186 		/* XXX We can enable the SMBus here by writing 1 to
    187 		 * SMB_HOST_CONFIG, but do we want to?
    188 		 */
    189 		goto core_pcib;
    190 	}
    191 
    192 #ifdef VIAPCIB_DEBUG
    193 	switch (val & 0x0e) {
    194 	case 8:
    195 		printf(": interrupting at irq 9\n");
    196 		break;
    197 	case 0:
    198 		printf(": interrupting at SMI#\n");
    199 		break;
    200 	default:
    201 		printf(": interrupt misconfigured\n");
    202 		break;
    203 	}
    204 #endif /* !VIAPCIB_DEBUG */
    205 
    206 	val = pci_conf_read(pa->pa_pc, pa->pa_tag, SMB_REVISION);
    207 	sc->sc_revision = val;
    208 
    209 core_pcib:
    210 	pcibattach(parent, self, opaque);
    211 
    212 	if (addr != 0) {
    213 		struct i2cbus_attach_args iba;
    214 		uint8_t b;
    215 
    216 		printf("%s: SMBus found at 0x%x (revision 0x%x)\n",
    217 		    sc->sc_dev.dv_xname, addr, sc->sc_revision);
    218 
    219 		/* Disable slave function */
    220 		b = viapcib_smbus_read(sc, SMBSLVCNT);
    221 		viapcib_smbus_write(sc, SMBSLVCNT, b & ~1);
    222 
    223 		memset(&sc->sc_i2c, 0, sizeof(sc->sc_i2c));
    224 #ifdef I2C_TYPE_SMBUS
    225 		iba.iba_type = I2C_TYPE_SMBUS;
    226 #endif
    227 		iba.iba_tag = &sc->sc_i2c;
    228 		iba.iba_tag->ic_cookie = (void *)sc;
    229 		iba.iba_tag->ic_acquire_bus = viapcib_acquire_bus;
    230 		iba.iba_tag->ic_release_bus = viapcib_release_bus;
    231 		iba.iba_tag->ic_exec = viapcib_exec;
    232 
    233 		config_found_ia(&sc->sc_dev, "i2cbus", &iba, iicbus_print);
    234 	}
    235 
    236 	return;
    237 }
    238 
    239 static int
    240 viapcib_wait(struct viapcib_softc *sc)
    241 {
    242 	int rv, timeout;
    243 	uint8_t val;
    244 
    245 	timeout = VIAPCIB_SMBUS_TIMEOUT;
    246 	rv = 0;
    247 
    248 	while (timeout--) {
    249 		val = viapcib_smbus_read(sc, SMBHSTSTS);
    250 		if (!(val & SMBHSTSTS_BUSY) && (val & SMBHSTSTS_INTR))
    251 			break;
    252 		DELAY(10);
    253 	}
    254 
    255 	if (timeout == 0)
    256 		rv = EBUSY;
    257 
    258 	if ((val & SMBHSTSTS_FAILED) || (val & SMBHSTSTS_COLLISION) ||
    259 	    (val & SMBHSTSTS_ERROR))
    260 		rv = EIO;
    261 
    262 	viapcib_clear(sc);
    263 
    264 	return rv;
    265 }
    266 
    267 static int
    268 viapcib_clear(struct viapcib_softc *sc)
    269 {
    270 	viapcib_smbus_write(sc, SMBHSTSTS,
    271 	    (SMBHSTSTS_FAILED | SMBHSTSTS_COLLISION | SMBHSTSTS_ERROR |
    272 	     SMBHSTSTS_INTR));
    273 	DELAY(10);
    274 
    275 	return 0;
    276 }
    277 
    278 static int
    279 viapcib_busy(struct viapcib_softc *sc)
    280 {
    281 	uint8_t val;
    282 
    283 	val = viapcib_smbus_read(sc, SMBHSTSTS);
    284 
    285 	return (val & SMBHSTSTS_BUSY);
    286 }
    287 
    288 static int
    289 viapcib_acquire_bus(void *opaque, int flags)
    290 {
    291 	struct viapcib_softc *sc;
    292 
    293 	DPRINTF(("viapcib_i2c_acquire_bus(%p, 0x%x)\n", opaque, flags));
    294 
    295 	sc = (struct viapcib_softc *)opaque;
    296 
    297 	simple_lock(&sc->sc_lock);
    298 
    299 	return 0;
    300 }
    301 
    302 static void
    303 viapcib_release_bus(void *opaque, int flags)
    304 {
    305 	struct viapcib_softc *sc;
    306 
    307 	DPRINTF(("viapcib_i2c_release_bus(%p, 0x%x)\n", opaque, flags));
    308 
    309 	sc = (struct viapcib_softc *)opaque;
    310 
    311 	simple_unlock(&sc->sc_lock);
    312 
    313 	return;
    314 }
    315 
    316 static int
    317 viapcib_exec(void *opaque, i2c_op_t op, i2c_addr_t addr, const void *vcmd,
    318     size_t cmdlen, void *vbuf, size_t buflen, int flags)
    319 {
    320 	struct viapcib_softc *sc;
    321 	uint8_t cmd;
    322 	int rv = -1;
    323 
    324 	DPRINTF(("viapcib_exec(%p, 0x%x, 0x%x, %p, %d, %p, %d, 0x%x)\n",
    325 	    opaque, op, addr, vcmd, cmdlen, vbuf, buflen, flags));
    326 
    327 	sc = (struct viapcib_softc *)opaque;
    328 
    329 	if (op != I2C_OP_READ_WITH_STOP &&
    330 	    op != I2C_OP_WRITE_WITH_STOP)
    331 		return -1;
    332 
    333 	if (cmdlen > 0)
    334 		cmd = *(uint8_t *)(__UNCONST(vcmd)); /* XXX */
    335 
    336 	switch (cmdlen) {
    337 	case 0:
    338 		switch (buflen) {
    339 		case 0:
    340 			/* SMBus quick read/write */
    341 			if (I2C_OP_READ_P(op))
    342 				rv = viapcib_smbus_quick_read(sc, addr);
    343 			else
    344 				rv = viapcib_smbus_quick_write(sc, addr);
    345 
    346 			return rv;
    347 		case 1:
    348 			/* SMBus send/receive byte */
    349 			if (I2C_OP_READ_P(op))
    350 				rv = viapcib_smbus_send_byte(sc, addr,
    351 				    *(uint8_t *)vbuf);
    352 			else
    353 				rv = viapcib_smbus_receive_byte(sc, addr,
    354 				    (uint8_t *)vbuf);
    355 			return rv;
    356 		default:
    357 			return -1;
    358 		}
    359 	case 1:
    360 		switch (buflen) {
    361 		case 0:
    362 			return -1;
    363 		case 1:
    364 			/* SMBus read/write byte */
    365 			if (I2C_OP_READ_P(op))
    366 				rv = viapcib_smbus_read_byte(sc, addr,
    367 				    cmd, (uint8_t *)vbuf);
    368 			else
    369 				rv = viapcib_smbus_write_byte(sc, addr,
    370 				    cmd, *(uint8_t *)vbuf);
    371 			return rv;
    372 		case 2:
    373 			/* SMBus read/write word */
    374 			if (I2C_OP_READ_P(op))
    375 				rv = viapcib_smbus_read_word(sc, addr,
    376 				    cmd, (uint16_t *)vbuf);
    377 			else
    378 				rv = viapcib_smbus_write_word(sc, addr,
    379 				    cmd, *(uint16_t *)vbuf);
    380 			return rv;
    381 		default:
    382 			/* SMBus read/write block */
    383 			if (I2C_OP_READ_P(op))
    384 				rv = viapcib_smbus_block_read(sc, addr,
    385 				    cmd, buflen, vbuf);
    386 			else
    387 				rv = viapcib_smbus_block_write(sc, addr,
    388 				    cmd, buflen, vbuf);
    389 			return rv;
    390 		}
    391 	}
    392 
    393 	return -1; /* XXX ??? */
    394 }
    395 
    396 static int
    397 viapcib_smbus_quick_write(void *opaque, i2c_addr_t slave)
    398 {
    399 	struct viapcib_softc *sc;
    400 
    401 	sc = (struct viapcib_softc *)opaque;
    402 
    403 	DPRINTF(("viapcib_smbus_quick_write(%p, 0x%x)\n", opaque, slave));
    404 
    405 	viapcib_clear(sc);
    406 	if (viapcib_busy(sc))
    407 		return EBUSY;
    408 
    409 	viapcib_smbus_write(sc, SMBHSTADD, (slave & 0x7f) << 1);
    410 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_QUICK);
    411 	if (viapcib_wait(sc))
    412 		return EBUSY;
    413 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_QUICK | SMBHSTCNT_START);
    414 
    415 	return viapcib_wait(sc);
    416 }
    417 
    418 static int
    419 viapcib_smbus_quick_read(void *opaque, i2c_addr_t slave)
    420 {
    421 	struct viapcib_softc *sc;
    422 
    423 	sc = (struct viapcib_softc *)opaque;
    424 
    425 	DPRINTF(("viapcib_smbus_quick_read(%p, 0x%x)\n", opaque, slave));
    426 
    427 	viapcib_clear(sc);
    428 	if (viapcib_busy(sc))
    429 		return EBUSY;
    430 
    431 	viapcib_smbus_write(sc, SMBHSTADD, ((slave & 0x7f) << 1) | 1);
    432 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_QUICK);
    433 	if (viapcib_wait(sc))
    434 		return EBUSY;
    435 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_QUICK | SMBHSTCNT_START);
    436 
    437 	return viapcib_wait(sc);
    438 }
    439 
    440 static int
    441 viapcib_smbus_send_byte(void *opaque, i2c_addr_t slave, uint8_t byte)
    442 {
    443 	struct viapcib_softc *sc;
    444 
    445 	sc = (struct viapcib_softc *)opaque;
    446 
    447 	DPRINTF(("viapcib_smbus_send_byte(%p, 0x%x, 0x%x)\n", opaque,
    448 	    slave, byte));
    449 
    450 	viapcib_clear(sc);
    451 	if (viapcib_busy(sc))
    452 		return EBUSY;
    453 
    454 	viapcib_smbus_write(sc, SMBHSTADD, (slave & 0x7f) << 1);
    455 	viapcib_smbus_write(sc, SMBHSTCMD, byte);
    456 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_SENDRECV);
    457 	if (viapcib_wait(sc))
    458 		return EBUSY;
    459 	viapcib_smbus_write(sc, SMBHSTCNT,
    460 	    SMBHSTCNT_START | SMBHSTCNT_SENDRECV);
    461 
    462 	return viapcib_wait(sc);
    463 }
    464 
    465 static int
    466 viapcib_smbus_receive_byte(void *opaque, i2c_addr_t slave, uint8_t *pbyte)
    467 {
    468 	struct viapcib_softc *sc;
    469 	int rv;
    470 
    471 	sc = (struct viapcib_softc *)opaque;
    472 
    473 	DPRINTF(("viapcib_smbus_receive_byte(%p, 0x%x, %p)\n", opaque,
    474 	    slave, pbyte));
    475 
    476 	viapcib_clear(sc);
    477 	if (viapcib_busy(sc))
    478 		return EBUSY;
    479 
    480 	viapcib_smbus_write(sc, SMBHSTADD, ((slave & 0x7f) << 1) | 1);
    481 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_SENDRECV);
    482 	if (viapcib_wait(sc))
    483 		return EBUSY;
    484 	viapcib_smbus_write(sc, SMBHSTCNT,
    485 	    SMBHSTCNT_START | SMBHSTCNT_SENDRECV);
    486 
    487 	rv = viapcib_wait(sc);
    488 	if (rv == 0)
    489 		*pbyte = viapcib_smbus_read(sc, SMBHSTDAT0);
    490 
    491 	return rv;
    492 }
    493 
    494 static int
    495 viapcib_smbus_write_byte(void *opaque, i2c_addr_t slave, uint8_t cmd,
    496 		   int8_t byte)
    497 {
    498 	struct viapcib_softc *sc;
    499 
    500 	sc = (struct viapcib_softc *)opaque;
    501 
    502 	DPRINTF(("viapcib_smbus_write_byte(%p, 0x%x, 0x%x, 0x%x)\n", opaque,
    503 	    slave, cmd, byte));
    504 
    505 	viapcib_clear(sc);
    506 	if (viapcib_busy(sc))
    507 		return EBUSY;
    508 
    509 	viapcib_smbus_write(sc, SMBHSTADD, (slave & 0x7f) << 1);
    510 	viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    511 	viapcib_smbus_write(sc, SMBHSTDAT0, byte);
    512 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_BYTE);
    513 	if (viapcib_wait(sc))
    514 		return EBUSY;
    515 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_START | SMBHSTCNT_BYTE);
    516 
    517 	return viapcib_wait(sc);
    518 }
    519 
    520 static int
    521 viapcib_smbus_read_byte(void *opaque, i2c_addr_t slave, uint8_t cmd,
    522 		  int8_t *pbyte)
    523 {
    524 	struct viapcib_softc *sc;
    525 	int rv;
    526 
    527 	sc = (struct viapcib_softc *)opaque;
    528 
    529 	DPRINTF(("viapcib_smbus_read_byte(%p, 0x%x, 0x%x, %p)\n", opaque,
    530 	    slave, cmd, pbyte));
    531 
    532 	viapcib_clear(sc);
    533 	if (viapcib_busy(sc))
    534 		return EBUSY;
    535 
    536 	viapcib_smbus_write(sc, SMBHSTADD, ((slave & 0x7f) << 1) | 1);
    537 	viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    538 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_BYTE);
    539 	if (viapcib_wait(sc))
    540 		return EBUSY;
    541 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_START | SMBHSTCNT_BYTE);
    542 	rv = viapcib_wait(sc);
    543 	if (rv == 0)
    544 		*pbyte = viapcib_smbus_read(sc, SMBHSTDAT0);
    545 
    546 	return rv;
    547 }
    548 
    549 static int
    550 viapcib_smbus_write_word(void *opaque, i2c_addr_t slave, uint8_t cmd,
    551 		   int16_t word)
    552 {
    553 	struct viapcib_softc *sc;
    554 
    555 	sc = (struct viapcib_softc *)opaque;
    556 
    557 	DPRINTF(("viapcib_smbus_write_word(%p, 0x%x, 0x%x, 0x%x)\n", opaque,
    558 	    slave, cmd, word));
    559 
    560 	viapcib_clear(sc);
    561 	if (viapcib_busy(sc))
    562 		return EBUSY;
    563 
    564 	viapcib_smbus_write(sc, SMBHSTADD, (slave & 0x7f) << 1);
    565 	viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    566 	viapcib_smbus_write(sc, SMBHSTDAT0, word & 0x00ff);
    567 	viapcib_smbus_write(sc, SMBHSTDAT1, (word & 0xff00) >> 8);
    568 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_WORD);
    569 	if (viapcib_wait(sc))
    570 		return EBUSY;
    571 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_START | SMBHSTCNT_WORD);
    572 
    573 	return viapcib_wait(sc);
    574 }
    575 
    576 static int
    577 viapcib_smbus_read_word(void *opaque, i2c_addr_t slave, uint8_t cmd,
    578 		  int16_t *pword)
    579 {
    580 	struct viapcib_softc *sc;
    581 	int rv;
    582 	int8_t high, low;
    583 
    584 	sc = (struct viapcib_softc *)opaque;
    585 
    586 	DPRINTF(("viapcib_smbus_read_word(%p, 0x%x, 0x%x, %p)\n", opaque,
    587 	    slave, cmd, pword));
    588 
    589 	viapcib_clear(sc);
    590 	if (viapcib_busy(sc))
    591 		return EBUSY;
    592 
    593 	viapcib_smbus_write(sc, SMBHSTADD, ((slave & 0x7f) << 1) | 1);
    594 	viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    595 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_WORD);
    596 	if (viapcib_wait(sc))
    597 		return EBUSY;
    598 	viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_START | SMBHSTCNT_WORD);
    599 
    600 	rv = viapcib_wait(sc);
    601 	if (rv == 0) {
    602 		low = viapcib_smbus_read(sc, SMBHSTDAT0);
    603 		high = viapcib_smbus_read(sc, SMBHSTDAT1);
    604 		*pword = ((high & 0xff) << 8) | (low & 0xff);
    605 	}
    606 
    607 	return rv;
    608 }
    609 
    610 static int
    611 viapcib_smbus_block_write(void *opaque, i2c_addr_t slave, uint8_t cmd,
    612 		    int cnt, void *data)
    613 {
    614 	struct viapcib_softc *sc;
    615 	int8_t *buf;
    616 	int remain, len, i;
    617 	int rv;
    618 
    619 	sc = (struct viapcib_softc *)opaque;
    620 	buf = (int8_t *)data;
    621 	rv = 0;
    622 
    623 	DPRINTF(("viapcib_smbus_block_write(%p, 0x%x, 0x%x, %d, %p)\n",
    624 	    opaque, slave, cmd, cnt, data));
    625 
    626 	viapcib_clear(sc);
    627 	if (viapcib_busy(sc))
    628 		return EBUSY;
    629 
    630 	remain = cnt;
    631 	while (remain) {
    632 		len = min(remain, SMB_MAXBLOCKSIZE);
    633 
    634 		viapcib_smbus_write(sc, SMBHSTADD, (slave & 0x7f) << 1);
    635 		viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    636 		viapcib_smbus_write(sc, SMBHSTDAT0, len);
    637 		i = viapcib_smbus_read(sc, SMBHSTCNT);
    638 		/* XXX FreeBSD does this, but it looks wrong */
    639 		for (i = 0; i < len; i++) {
    640 			viapcib_smbus_write(sc, SMBBLKDAT,
    641 			    buf[cnt - remain + i]);
    642 		}
    643 		viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_BLOCK);
    644 		if (viapcib_wait(sc))
    645 			return EBUSY;
    646 		viapcib_smbus_write(sc, SMBHSTCNT,
    647 		    SMBHSTCNT_START | SMBHSTCNT_BLOCK);
    648 		if (viapcib_wait(sc))
    649 			return EBUSY;
    650 
    651 		remain -= len;
    652 	}
    653 
    654 	return rv;
    655 }
    656 
    657 static int
    658 viapcib_smbus_block_read(void *opaque, i2c_addr_t slave, uint8_t cmd,
    659 			 int cnt, void *data)
    660 {
    661 	struct viapcib_softc *sc;
    662 	int8_t *buf;
    663 	int remain, len, i;
    664 	int rv;
    665 
    666 	sc = (struct viapcib_softc *)opaque;
    667 	buf = (int8_t *)data;
    668 	rv = 0;
    669 
    670 	DPRINTF(("viapcib_smbus_block_read(%p, 0x%x, 0x%x, %d, %p)\n",
    671 	    opaque, slave, cmd, cnt, data));
    672 
    673 	viapcib_clear(sc);
    674 	if (viapcib_busy(sc))
    675 		return EBUSY;
    676 
    677 	remain = cnt;
    678 	while (remain) {
    679 		viapcib_smbus_write(sc, SMBHSTADD, ((slave & 0x7f) << 1) | 1);
    680 		viapcib_smbus_write(sc, SMBHSTCMD, cmd);
    681 		viapcib_smbus_write(sc, SMBHSTCNT, SMBHSTCNT_BLOCK);
    682 		if (viapcib_wait(sc))
    683 			return EBUSY;
    684 		viapcib_smbus_write(sc, SMBHSTCNT,
    685 		    SMBHSTCNT_START | SMBHSTCNT_BLOCK);
    686 		if (viapcib_wait(sc))
    687 			return EBUSY;
    688 
    689 		len = viapcib_smbus_read(sc, SMBHSTDAT0);
    690 		i = viapcib_smbus_read(sc, SMBHSTCNT);
    691 
    692 		len = min(len, remain);
    693 
    694 		/* FreeBSD does this too... */
    695 		for (i = 0; i < len; i++) {
    696 			buf[cnt - remain + i] =
    697 			    viapcib_smbus_read(sc, SMBBLKDAT);
    698 		}
    699 
    700 		remain -= len;
    701 	}
    702 
    703 	return rv;
    704 }
    705