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mca_machdep.c revision 1.4.6.4
      1 /*	$NetBSD: mca_machdep.c,v 1.4.6.4 2002/11/11 21:59:26 nathanw Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
      5  * Copyright (c) 1996-1999 Scott D. Telford.
      6  * All rights reserved.
      7  *
      8  * This code is derived from software contributed to The NetBSD Foundation
      9  * by Scott Telford <s.telford (at) ed.ac.uk> and Jaromir Dolecek
     10  * <jdolecek (at) NetBSD.org>.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the NetBSD
     23  *	Foundation, Inc. and its contributors.
     24  * 4. Neither the name of The NetBSD Foundation nor the names of its
     25  *    contributors may be used to endorse or promote products derived
     26  *    from this software without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     29  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     30  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     31  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     32  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     33  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     34  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     35  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     36  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     37  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     38  * POSSIBILITY OF SUCH DAMAGE.
     39  */
     40 
     41 /*
     42  * Machine-specific functions for MCA autoconfiguration.
     43  */
     44 
     45 #include <sys/cdefs.h>
     46 __KERNEL_RCSID(0, "$NetBSD: mca_machdep.c,v 1.4.6.4 2002/11/11 21:59:26 nathanw Exp $");
     47 
     48 #include <sys/types.h>
     49 #include <sys/param.h>
     50 #include <sys/device.h>
     51 #include <sys/malloc.h>
     52 #include <sys/systm.h>
     53 #include <sys/syslog.h>
     54 #include <sys/time.h>
     55 #include <sys/kernel.h>
     56 
     57 #include <machine/bioscall.h>
     58 #include <machine/psl.h>
     59 
     60 #define _I386_BUS_DMA_PRIVATE
     61 #include <machine/bus.h>
     62 
     63 #include <i386/isa/icu.h>
     64 #include <dev/isa/isavar.h>
     65 #include <dev/isa/isareg.h>
     66 #include <dev/mca/mcavar.h>
     67 #include <dev/mca/mcareg.h>
     68 
     69 #include "isa.h"
     70 #include "opt_mcaverbose.h"
     71 
     72 /* System Configuration Block - this info is returned by the BIOS call */
     73 struct bios_config {
     74 	u_int16_t	count;
     75 	u_int8_t	model;
     76 	u_int8_t	submodel;
     77 	u_int8_t	bios_rev;
     78 	u_int8_t	feature1;
     79 #define FEATURE_MCAISA	0x01	/* Machine contains both MCA and ISA bus */
     80 #define FEATURE_MCABUS	0x02	/* Machine has MCA bus instead of ISA	*/
     81 #define FEATURE_EBDA	0x04	/* Extended BIOS data area allocated	*/
     82 #define FEATURE_WAITEV	0x08	/* Wait for external event is supported	*/
     83 #define FEATURE_KBDINT	0x10	/* Keyboard intercept called by Int 09h	*/
     84 #define FEATURE_RTC	0x20	/* Real-time clock present		*/
     85 #define FEATURE_IC2	0x40	/* Second interrupt chip present	*/
     86 #define FEATURE_DMA3	0x80	/* DMA channel 3 used by hard disk BIOS	*/
     87 	u_int8_t	feature2;
     88 	u_int8_t	pad[9];
     89 } __attribute__ ((packed));
     90 
     91 /*
     92  * Used to encode DMA channel into ISA DMA cookie. We use upper 4 bits of
     93  * ISA DMA cookie id_flags, it's unused.
     94  */
     95 struct i386_isa_dma_cookie {
     96 	int id_flags;
     97 	/* We don't care about rest */
     98 };
     99 
    100 /* ISA DMA stuff - see i386/isa/isa_machdep.c */
    101 int	_isa_bus_dmamap_create __P((bus_dma_tag_t, bus_size_t, int,
    102 	    bus_size_t, bus_size_t, int, bus_dmamap_t *));
    103 void	_isa_bus_dmamap_destroy __P((bus_dma_tag_t, bus_dmamap_t));
    104 int	_isa_bus_dmamap_load __P((bus_dma_tag_t, bus_dmamap_t, void *,
    105 	    bus_size_t, struct proc *, int));
    106 void	_isa_bus_dmamap_unload __P((bus_dma_tag_t, bus_dmamap_t));
    107 void	_isa_bus_dmamap_sync __P((bus_dma_tag_t, bus_dmamap_t,
    108 	    bus_addr_t, bus_size_t, int));
    109 
    110 int	_isa_bus_dmamem_alloc __P((bus_dma_tag_t, bus_size_t, bus_size_t,
    111 	    bus_size_t, bus_dma_segment_t *, int, int *, int));
    112 
    113 static void	_mca_bus_dmamap_sync __P((bus_dma_tag_t, bus_dmamap_t,
    114 		    bus_addr_t, bus_size_t, int));
    115 static int	_mca_bus_dmamap_load_mbuf __P((bus_dma_tag_t, bus_dmamap_t,
    116 		    struct mbuf *, int));
    117 static int	_mca_bus_dmamap_load_uio __P((bus_dma_tag_t, bus_dmamap_t,
    118 		    struct uio *, int));
    119 static int	_mca_bus_dmamap_load_raw __P((bus_dma_tag_t, bus_dmamap_t,
    120 		    bus_dma_segment_t *, int, bus_size_t, int));
    121 
    122 /*
    123  * For now, we use MCA DMA to 0-16M always. Some IBM PS/2 have 32bit MCA bus,
    124  * but majority of them have 24bit only.
    125  */
    126 #define	MCA_DMA_BOUNCE_THRESHOLD	(16 * 1024 * 1024)
    127 
    128 struct i386_bus_dma_tag mca_bus_dma_tag = {
    129 	MCA_DMA_BOUNCE_THRESHOLD,		/* _bounce_thresh */
    130 	_isa_bus_dmamap_create,
    131 	_isa_bus_dmamap_destroy,
    132 	_isa_bus_dmamap_load,
    133 	_mca_bus_dmamap_load_mbuf,
    134 	_mca_bus_dmamap_load_uio,
    135 	_mca_bus_dmamap_load_raw,
    136 	_isa_bus_dmamap_unload,
    137 	_mca_bus_dmamap_sync,
    138 	_isa_bus_dmamem_alloc,
    139 	_bus_dmamem_free,
    140 	_bus_dmamem_map,
    141 	_bus_dmamem_unmap,
    142 	_bus_dmamem_mmap,
    143 };
    144 
    145 /* Updated in mca_busprobe() if appropriate. */
    146 int MCA_system = 0;
    147 
    148 /* Used to kick MCA DMA controller */
    149 #define DMA_CMD		0x18		/* command the controller */
    150 #define DMA_EXEC	0x1A		/* tell controller how to do things */
    151 static bus_space_handle_t dmaiot, dmacmdh, dmaexech;
    152 
    153 /*
    154  * MCA DMA controller commands. The exact sense of individual bits
    155  * are from Tymm Twillman <tymm (at) computer.org>, who worked on Linux MCA DMA
    156  * support.
    157  */
    158 #define DMACMD_SET_IO		0x00	/* set port (16bit) for i/o transfer */
    159 #define DMACMD_SET_ADDR		0x20	/* set addr (24bit) for i/o transfer */
    160 #define DMACMD_GET_ADDR		0x30	/* get addr (24bit) for i/o transfer */
    161 #define	DMACMD_SET_CNT		0x40	/* set memory size for DMA (16b) */
    162 #define DMACMD_GET_CNT		0x50	/* get count of remaining bytes in DMA*/
    163 #define DMACMD_GET_STATUS	0x60	/* ?? */
    164 #define DMACMD_SET_MODE		0x70	/* set DMA mode */
    165 # define DMACMD_MODE_XFER	0x04	/* do transfer, read by default */
    166 # define DMACMD_MODE_READ	0x08	/* read transfer */
    167 # define DMACMD_MODE_WRITE	0x00	/* write transfer */
    168 # define DMACMD_MODE_IOPORT	0x01	/* DMA from/to IO register */
    169 # define DMACMD_MODE_16BIT	0x40	/* 16bit transfers (default 8bit) */
    170 #define DMACMD_SET_ARBUS	0x80	/* ?? */
    171 #define DMACMD_MASK		0x90	/* command mask */
    172 #define DMACMD_RESET_MASK	0xA0	/* reset */
    173 #define DMACMD_MASTER_CLEAR	0xD0	/* ?? */
    174 
    175 /*
    176  * Map the MCA DMA controller registers.
    177  */
    178 void
    179 mca_attach_hook(parent, self, mba)
    180 	struct device *parent, *self;
    181 	struct mcabus_attach_args *mba;
    182 {
    183 	dmaiot = mba->mba_iot;
    184 
    185 	if (bus_space_map(dmaiot, DMA_CMD, 1, 0, &dmacmdh)
    186 	    || bus_space_map(dmaiot, DMA_EXEC, 1, 0, &dmaexech))
    187 		panic("%s: couldn't map DMA registers",
    188 			mba->mba_busname);
    189 }
    190 
    191 /*
    192  * Read value of MCA POS register "reg" in slot "slot".
    193  */
    194 
    195 int
    196 mca_conf_read(mc, slot, reg)
    197 	mca_chipset_tag_t mc;
    198 	int slot, reg;
    199 {
    200 	int	data;
    201 
    202 	slot &= 7;	/* slot must be in range 0-7 */
    203 	outb(MCA_MB_SETUP_REG, 0xff); /* ensure m/board setup is disabled */
    204 	outb(MCA_ADAP_SETUP_REG, slot | MCA_ADAP_SET);
    205 	data = inb(MCA_POS_REG(reg));
    206 	outb(MCA_ADAP_SETUP_REG, 0);
    207 	return data;
    208 }
    209 
    210 
    211 /*
    212  * Write "data" to MCA POS register "reg" in slot "slot".
    213  */
    214 
    215 void
    216 mca_conf_write(mc, slot, reg, data)
    217 	mca_chipset_tag_t mc;
    218 	int slot, reg, data;
    219 {
    220 	slot&=7;	/* slot must be in range 0-7 */
    221 	outb(MCA_MB_SETUP_REG, 0xff); /* ensure m/board setup is disabled */
    222 	outb(MCA_ADAP_SETUP_REG, slot | MCA_ADAP_SET);
    223 	outb(MCA_POS_REG(reg), data);
    224 	outb(MCA_ADAP_SETUP_REG, 0);
    225 }
    226 
    227 #if NISA <= 0
    228 #error mca_intr_(dis)establish: needs ISA to be configured into kernel
    229 #endif
    230 
    231 #if 0
    232 const struct evcnt *
    233 mca_intr_establish(mca_chipset_tag_t mc, mca_intr_handle_t ih)
    234 {
    235 
    236 	/* XXX for now, no evcnt parent reported */
    237 	return NULL;
    238 }
    239 #endif
    240 
    241 void *
    242 mca_intr_establish(mc, ih, level, func, arg)
    243 	mca_chipset_tag_t mc;
    244 	mca_intr_handle_t ih;
    245 	int level, (*func) __P((void *));
    246 	void *arg;
    247 {
    248 	if (ih == 0 || ih >= ICU_LEN || ih == 2)
    249 		panic("mca_intr_establish: bogus handle 0x%x", ih);
    250 
    251 	/* MCA interrupts are always level-triggered */
    252 	return isa_intr_establish(NULL, ih, IST_LEVEL, level, func, arg);
    253 }
    254 
    255 void
    256 mca_intr_disestablish(mc, cookie)
    257 	mca_chipset_tag_t mc;
    258 	void *cookie;
    259 {
    260 	isa_intr_disestablish(NULL, cookie);
    261 }
    262 
    263 
    264 /*
    265  * Handle a NMI.
    266  * return true to panic system, false to ignore.
    267  */
    268 int
    269 mca_nmi()
    270 {
    271 	/*
    272 	* PS/2 MCA devices can generate NMIs - we can find out which
    273 	* slot generated it from the POS registers.
    274 	*/
    275 
    276 	int 	slot, mcanmi=0;
    277 
    278 	/* if there is no MCA bus, call isa_nmi() */
    279 	if (!MCA_system)
    280 		goto out;
    281 
    282 	/* ensure motherboard setup is disabled */
    283 	outb(MCA_MB_SETUP_REG, 0xff);
    284 
    285 	/* find if an MCA slot has the CHCK bit asserted (low) in POS 5 */
    286 	for(slot=0; slot<MCA_MAX_SLOTS; slot++) {
    287 		outb(MCA_ADAP_SETUP_REG, slot | MCA_ADAP_SET);
    288 		if ((inb(MCA_POS_REG(5)) & MCA_POS5_CHCK) == 0) {
    289 			mcanmi = 1;
    290 			/* find if CHCK status is available in POS 6/7 */
    291 			if((inb(MCA_POS_REG(5)) & MCA_POS5_CHCK_STAT) == 0)
    292 				log(LOG_CRIT, "MCA NMI: slot %d, POS6=0x%02x, POS7=0x%02x\n",
    293 					slot+1, inb(MCA_POS_REG(6)),
    294 						inb(MCA_POS_REG(7)));
    295 			else
    296 				log(LOG_CRIT, "MCA NMI: slot %d\n", slot+1);
    297 		}
    298 	}
    299 	outb(MCA_ADAP_SETUP_REG, 0);
    300 
    301    out:
    302 	if (!mcanmi) {
    303 		/* no CHCK bits asserted, assume ISA NMI */
    304 		return (isa_nmi());
    305 	} else
    306 		return(0);
    307 }
    308 
    309 /*
    310  * We can obtain the information about MCA bus presence via
    311  * GET CONFIGURATION BIOS call - int 0x15, function 0xc0.
    312  * The call returns a pointer to memory place with the configuration block
    313  * in es:bx (on AT-compatible, e.g. all we care about, computers).
    314  *
    315  * Configuration block contains block length (2 bytes), model
    316  * number (1 byte), submodel number (1 byte), BIOS revision
    317  * (1 byte) and up to 5 feature bytes. We only care about
    318  * first feature byte.
    319  */
    320 void
    321 mca_busprobe()
    322 {
    323 	struct bioscallregs regs;
    324 	struct bios_config *scp;
    325 	paddr_t             paddr;
    326 	char buf[50];
    327 
    328 	memset(&regs, 0, sizeof(regs));
    329 	regs.AH = 0xc0;
    330 	bioscall(0x15, &regs);
    331 
    332 	if ((regs.EFLAGS & PSL_C) || regs.AH != 0) {
    333 #ifdef DEBUG
    334 		printf("BIOS CFG: Not supported. Not AT-compatible?\n");
    335 #endif
    336 		return;
    337 	}
    338 
    339 	paddr = (regs.ES << 4) + regs.BX;
    340 	scp = (struct bios_config *)ISA_HOLE_VADDR(paddr);
    341 
    342 #if 1 /* MCAVERBOSE */
    343 	bitmask_snprintf(((scp->feature2 & 1)<< 8) | scp->feature1,
    344 		"\20"
    345 		"\01MCA+ISA"
    346 		"\02MCA"
    347 		"\03EBDA"
    348 		"\04WAITEV"
    349 		"\05KBDINT"
    350 		"\06RTC"
    351 		"\07IC2"
    352 		"\010DMA3B"
    353 		"\011DMA32\n",
    354 		buf, sizeof(buf));
    355 
    356 	printf("BIOS CFG: Model-SubM-Rev: %02x-%02x-%02x, 0x%s\n",
    357 		scp->model, scp->submodel, scp->bios_rev, buf);
    358 #endif
    359 
    360 	MCA_system = (scp->feature1 & FEATURE_MCABUS) ? 1 : 0;
    361 }
    362 
    363 #define PORT_DISKLED	0x92
    364 #define DISKLED_ON	0x40
    365 
    366 /*
    367  * Light disk busy LED on IBM PS/2.
    368  */
    369 void
    370 mca_disk_busy(void)
    371 {
    372 	outb(PORT_DISKLED, inb(PORT_DISKLED) | DISKLED_ON);
    373 }
    374 
    375 /*
    376  * Turn off disk LED on IBM PS/2.
    377  */
    378 void
    379 mca_disk_unbusy(void)
    380 {
    381 	outb(PORT_DISKLED, inb(PORT_DISKLED) & ~DISKLED_ON);
    382 }
    383 
    384 /*
    385  * -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    386  * MCA DMA specific stuff. We use ISA routines for bulk of the work,
    387  * since MCA shares much of the charasteristics with it. We just hook
    388  * the DMA channel initialization and kick MCA DMA controller appropriately.
    389  * -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    390  */
    391 
    392 /*
    393  * Like _mca_bus_dmamap_load(), but for mbufs.
    394  */
    395 static int
    396 _mca_bus_dmamap_load_mbuf(t, map, m0, flags)
    397 	bus_dma_tag_t t;
    398 	bus_dmamap_t map;
    399 	struct mbuf *m0;
    400 	int flags;
    401 {
    402 
    403 	panic("_mca_bus_dmamap_load_mbuf: not implemented");
    404 }
    405 
    406 /*
    407  * Like _mca_bus_dmamap_load(), but for uios.
    408  */
    409 static int
    410 _mca_bus_dmamap_load_uio(t, map, uio, flags)
    411 	bus_dma_tag_t t;
    412 	bus_dmamap_t map;
    413 	struct uio *uio;
    414 	int flags;
    415 {
    416 
    417 	panic("_mca_bus_dmamap_load_uio: not implemented");
    418 }
    419 
    420 /*
    421  * Like _mca_bus_dmamap_load(), but for raw memory allocated with
    422  * bus_dmamem_alloc().
    423  */
    424 static int
    425 _mca_bus_dmamap_load_raw(t, map, segs, nsegs, size, flags)
    426 	bus_dma_tag_t t;
    427 	bus_dmamap_t map;
    428 	bus_dma_segment_t *segs;
    429 	int nsegs;
    430 	bus_size_t size;
    431 	int flags;
    432 {
    433 
    434 	panic("_mca_bus_dmamap_load_raw: not implemented");
    435 }
    436 
    437 /*
    438  * Synchronize a MCA DMA map.
    439  */
    440 static void
    441 _mca_bus_dmamap_sync(t, map, offset, len, ops)
    442 	bus_dma_tag_t t;
    443 	bus_dmamap_t map;
    444 	bus_addr_t offset;
    445 	bus_size_t len;
    446 	int ops;
    447 {
    448 	struct i386_isa_dma_cookie *cookie;
    449 	bus_addr_t phys;
    450 	bus_size_t cnt;
    451 	int dmach, mode;
    452 
    453 	_isa_bus_dmamap_sync(t, map, offset, len, ops);
    454 
    455 	/*
    456 	 * Don't do anything if not using the DMA controller.
    457 	 */
    458 	if ((map->_dm_flags & _MCABUS_DMA_USEDMACTRL) == 0)
    459 		return;
    460 
    461 	/*
    462 	 * Don't do anything if not PRE* operation, allow only
    463 	 * one of PREREAD and PREWRITE.
    464 	 */
    465 	if (ops != BUS_DMASYNC_PREREAD && ops != BUS_DMASYNC_PREWRITE)
    466 		return;
    467 
    468 	cookie = (struct i386_isa_dma_cookie *)map->_dm_cookie;
    469 	dmach = (cookie->id_flags & 0xf0) >> 4;
    470 
    471 	phys = map->dm_segs[0].ds_addr;
    472 	cnt = map->dm_segs[0].ds_len;
    473 
    474 	mode = DMACMD_MODE_XFER;
    475 	mode |= (ops == BUS_DMASYNC_PREREAD)
    476 			? DMACMD_MODE_READ : DMACMD_MODE_WRITE;
    477 	if (map->_dm_flags & MCABUS_DMA_IOPORT)
    478 		mode |= DMACMD_MODE_IOPORT;
    479 
    480 	/* Use 16bit DMA if requested */
    481 	if (map->_dm_flags & MCABUS_DMA_16BIT) {
    482 #ifdef DIAGNOSTIC
    483 		if ((cnt % 2) != 0) {
    484 			panic("_mca_bus_dmamap_sync: 16bit DMA and cnt %lu odd",
    485 				cnt);
    486 		}
    487 #endif
    488 		mode |= DMACMD_MODE_16BIT;
    489 		cnt /= 2;
    490 	}
    491 
    492 	/*
    493 	 * Initialize the MCA DMA controller appropriately. The exact
    494 	 * sequence to setup the controller is taken from Minix.
    495 	 */
    496 
    497 	/* Disable access to dma channel. */
    498 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_MASK | dmach);
    499 
    500 	/* Set the transfer mode. */
    501 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_MODE | dmach);
    502 	bus_space_write_1(dmaiot, dmaexech, 0, mode);
    503 
    504 	/* Set the address byte pointer. */
    505 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_ADDR | dmach);
    506 	/* address bits 0..7   */
    507 	bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 0) & 0xff);
    508 	/* address bits 8..15  */
    509 	bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 8) & 0xff);
    510 	/* address bits 16..23  */
    511 	bus_space_write_1(dmaiot, dmaexech, 0, (phys >> 16) & 0xff);
    512 
    513 	/* Set the count byte pointer */
    514 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_CNT | dmach);
    515 	/* count bits 0..7     */
    516 	bus_space_write_1(dmaiot, dmaexech, 0, ((cnt - 1) >> 0) & 0xff);
    517 	/* count bits 8..15    */
    518 	bus_space_write_1(dmaiot, dmaexech, 0, ((cnt - 1) >> 8) & 0xff);
    519 
    520 	/* Enable access to dma channel. */
    521 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_RESET_MASK | dmach);
    522 }
    523 
    524 /*
    525  * Allocate a dma map, and set up dma channel.
    526  */
    527 int
    528 mca_dmamap_create(t, size, flags, dmamp, dmach)
    529 	bus_dma_tag_t t;
    530 	bus_size_t size;
    531 	int flags;
    532 	bus_dmamap_t *dmamp;
    533 	int dmach;
    534 {
    535 	int error;
    536 	struct i386_isa_dma_cookie *cookie;
    537 
    538 #ifdef DEBUG
    539 	/* Sanity check */
    540 	if (dmach < 0 || dmach >= 16) {
    541 		printf("mcadma_create: invalid DMA channel %d\n",
    542 			dmach);
    543 		return (EINVAL);
    544 	}
    545 
    546 	if (size > 65536) {
    547 		panic("mca_dmamap_create: dmamap sz %ld > 65536",
    548 		    (long) size);
    549 	}
    550 #endif
    551 
    552 	/*
    553 	 * MCA DMA transfer can be maximum 65536 bytes long and must
    554 	 * be in one chunk. No specific boundary constraints are present.
    555 	 */
    556 	if ((error = bus_dmamap_create(t, size, 1, 65536, 0, flags, dmamp)))
    557 		return (error);
    558 
    559 	/* Encode DMA channel */
    560 	cookie = (struct i386_isa_dma_cookie *) (*dmamp)->_dm_cookie;
    561 	cookie->id_flags &= 0x0f;
    562 	cookie->id_flags |= dmach << 4;
    563 
    564 	/* Mark the dmamap as using DMA controller. Some devices
    565 	 * drive DMA themselves, and don't need the MCA DMA controller.
    566 	 * To distinguish the two, use a flag for dmamaps which use the DMA
    567 	 * controller.
    568  	 */
    569 	(*dmamp)->_dm_flags |= _MCABUS_DMA_USEDMACTRL;
    570 
    571 	return (0);
    572 }
    573 
    574 /*
    575  * Set I/O port for DMA. Implemented separately from _mca_bus_dmamap_sync()
    576  * so that it's available for one-shot setup.
    577  */
    578 void
    579 mca_dma_set_ioport(dma, port)
    580 	int dma;
    581 	u_int16_t port;
    582 {
    583 	/* Disable access to dma channel. */
    584 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_MASK | dma);
    585 
    586 	/* Set I/O port to use for DMA */
    587 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_SET_IO | dma);
    588 	bus_space_write_1(dmaiot, dmaexech, 0, port & 0xff);
    589 	bus_space_write_1(dmaiot, dmaexech, 0, (port >> 8) & 0xff);
    590 
    591 	/* Enable access to dma channel. */
    592 	bus_space_write_1(dmaiot, dmacmdh, 0, DMACMD_RESET_MASK | dma);
    593 }
    594