malta_intr.c revision 1.19.28.1       1  1.19.28.1   bouyer /*	$NetBSD: malta_intr.c,v 1.19.28.1 2011/03/05 15:09:38 bouyer Exp $	*/
      2        1.1   simonb 
      3        1.1   simonb /*
      4        1.1   simonb  * Copyright 2001, 2002 Wasabi Systems, Inc.
      5        1.1   simonb  * All rights reserved.
      6        1.1   simonb  *
      7        1.1   simonb  * Written by Jason R. Thorpe and Simon Burge for Wasabi Systems, Inc.
      8        1.1   simonb  *
      9        1.1   simonb  * Redistribution and use in source and binary forms, with or without
     10        1.1   simonb  * modification, are permitted provided that the following conditions
     11        1.1   simonb  * are met:
     12        1.1   simonb  * 1. Redistributions of source code must retain the above copyright
     13        1.1   simonb  *    notice, this list of conditions and the following disclaimer.
     14        1.1   simonb  * 2. Redistributions in binary form must reproduce the above copyright
     15        1.1   simonb  *    notice, this list of conditions and the following disclaimer in the
     16        1.1   simonb  *    documentation and/or other materials provided with the distribution.
     17        1.1   simonb  * 3. All advertising materials mentioning features or use of this software
     18        1.1   simonb  *    must display the following acknowledgement:
     19        1.1   simonb  *      This product includes software developed for the NetBSD Project by
     20        1.1   simonb  *      Wasabi Systems, Inc.
     21        1.1   simonb  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22        1.1   simonb  *    or promote products derived from this software without specific prior
     23        1.1   simonb  *    written permission.
     24        1.1   simonb  *
     25        1.1   simonb  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26        1.1   simonb  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27        1.1   simonb  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28        1.1   simonb  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29        1.1   simonb  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30        1.1   simonb  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31        1.1   simonb  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32        1.1   simonb  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33        1.1   simonb  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34        1.1   simonb  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35        1.1   simonb  * POSSIBILITY OF SUCH DAMAGE.
     36        1.1   simonb  */
     37        1.1   simonb 
     38        1.1   simonb /*
     39        1.1   simonb  * Platform-specific interrupt support for the MIPS Malta.
     40        1.1   simonb  */
     41        1.1   simonb 
     42        1.9    lukem #include <sys/cdefs.h>
     43  1.19.28.1   bouyer __KERNEL_RCSID(0, "$NetBSD: malta_intr.c,v 1.19.28.1 2011/03/05 15:09:38 bouyer Exp $");
     44  1.19.28.1   bouyer 
     45  1.19.28.1   bouyer #define	__INTR_PRIVATE
     46        1.1   simonb 
     47        1.1   simonb #include <sys/param.h>
     48        1.1   simonb #include <sys/device.h>
     49        1.1   simonb #include <sys/kernel.h>
     50        1.1   simonb #include <sys/malloc.h>
     51       1.10   simonb #include <sys/systm.h>
     52       1.14     yamt #include <sys/cpu.h>
     53        1.1   simonb 
     54        1.1   simonb #include <mips/locore.h>
     55        1.1   simonb 
     56        1.1   simonb #include <evbmips/malta/maltavar.h>
     57        1.1   simonb #include <evbmips/malta/pci/pcibvar.h>
     58        1.1   simonb 
     59        1.1   simonb #include <dev/ic/mc146818reg.h>		/* for malta_cal_timer() */
     60        1.1   simonb 
     61        1.1   simonb #include <dev/isa/isavar.h>
     62        1.1   simonb #include <dev/pci/pciidereg.h>
     63        1.1   simonb 
     64        1.1   simonb /*
     65        1.1   simonb  * This is a mask of bits to clear in the SR when we go to a
     66        1.1   simonb  * given hardware interrupt priority level.
     67        1.1   simonb  */
     68  1.19.28.1   bouyer static const struct ipl_sr_map malta_ipl_sr_map = {
     69  1.19.28.1   bouyer     .sr_bits = {
     70  1.19.28.1   bouyer 	[IPL_NONE] =		0,
     71  1.19.28.1   bouyer 	[IPL_SOFTCLOCK] =	MIPS_SOFT_INT_MASK_0,
     72  1.19.28.1   bouyer 	[IPL_SOFTNET] =		MIPS_SOFT_INT_MASK,
     73  1.19.28.1   bouyer 	[IPL_VM] =		MIPS_SOFT_INT_MASK | MIPS_INT_MASK_0,
     74  1.19.28.1   bouyer 	[IPL_SCHED] =		MIPS_SOFT_INT_MASK | MIPS_INT_MASK_0
     75  1.19.28.1   bouyer 				    | MIPS_INT_MASK_5,
     76  1.19.28.1   bouyer 	[IPL_DDB] =		MIPS_INT_MASK,
     77  1.19.28.1   bouyer 	[IPL_HIGH] =		MIPS_INT_MASK,
     78  1.19.28.1   bouyer     },
     79        1.1   simonb };
     80        1.1   simonb 
     81        1.1   simonb struct malta_cpuintr {
     82        1.1   simonb 	LIST_HEAD(, evbmips_intrhand) cintr_list;
     83        1.1   simonb 	struct evcnt cintr_count;
     84        1.1   simonb };
     85        1.1   simonb #define	NINTRS		5	/* MIPS INT0 - INT4 */
     86        1.1   simonb 
     87        1.1   simonb struct malta_cpuintr malta_cpuintrs[NINTRS];
     88  1.19.28.1   bouyer const char * const malta_cpuintrnames[NINTRS] = {
     89        1.1   simonb 	"int 0 (piix4)",
     90        1.1   simonb 	"int 1 (smi)",
     91        1.1   simonb 	"int 2 (uart)",
     92        1.1   simonb 	"int 3 (core hi/gt64120)",
     93        1.1   simonb 	"int 4 (core lo)",
     94        1.1   simonb };
     95        1.1   simonb 
     96        1.1   simonb static int	malta_pci_intr_map(struct pci_attach_args *, pci_intr_handle_t *);
     97        1.1   simonb static const char
     98        1.1   simonb 		*malta_pci_intr_string(void *, pci_intr_handle_t);
     99        1.1   simonb static const struct evcnt
    100        1.1   simonb 		*malta_pci_intr_evcnt(void *, pci_intr_handle_t);
    101        1.1   simonb static void	*malta_pci_intr_establish(void *, pci_intr_handle_t, int,
    102        1.1   simonb 		    int (*)(void *), void *);
    103        1.1   simonb static void	malta_pci_intr_disestablish(void *, void *);
    104        1.1   simonb static void	malta_pci_conf_interrupt(void *, int, int, int, int, int *);
    105        1.1   simonb static void	*malta_pciide_compat_intr_establish(void *, struct device *,
    106        1.1   simonb 		    struct pci_attach_args *, int, int (*)(void *), void *);
    107        1.1   simonb 
    108        1.1   simonb void
    109        1.1   simonb evbmips_intr_init(void)
    110        1.1   simonb {
    111  1.19.28.1   bouyer 	struct malta_config * const mcp = &malta_configuration;
    112  1.19.28.1   bouyer 
    113  1.19.28.1   bouyer 	ipl_sr_map = malta_ipl_sr_map;
    114        1.1   simonb 
    115  1.19.28.1   bouyer 	for (size_t i = 0; i < NINTRS; i++) {
    116        1.1   simonb 		LIST_INIT(&malta_cpuintrs[i].cintr_list);
    117        1.1   simonb 		evcnt_attach_dynamic(&malta_cpuintrs[i].cintr_count,
    118        1.1   simonb 		    EVCNT_TYPE_INTR, NULL, "mips", malta_cpuintrnames[i]);
    119        1.1   simonb 	}
    120        1.1   simonb 
    121        1.1   simonb 	mcp->mc_pc.pc_intr_v = NULL;
    122        1.1   simonb 	mcp->mc_pc.pc_intr_map = malta_pci_intr_map;
    123        1.1   simonb 	mcp->mc_pc.pc_intr_string = malta_pci_intr_string;
    124        1.1   simonb 	mcp->mc_pc.pc_intr_evcnt = malta_pci_intr_evcnt;
    125        1.1   simonb 	mcp->mc_pc.pc_intr_establish = malta_pci_intr_establish;
    126        1.1   simonb 	mcp->mc_pc.pc_intr_disestablish = malta_pci_intr_disestablish;
    127        1.1   simonb 	mcp->mc_pc.pc_conf_interrupt = malta_pci_conf_interrupt;
    128        1.1   simonb 	mcp->mc_pc.pc_pciide_compat_intr_establish =
    129        1.1   simonb 	    malta_pciide_compat_intr_establish;
    130        1.1   simonb }
    131        1.1   simonb 
    132        1.1   simonb void
    133        1.1   simonb malta_cal_timer(bus_space_tag_t st, bus_space_handle_t sh)
    134        1.1   simonb {
    135  1.19.28.1   bouyer 	struct cpu_info * const ci = curcpu();
    136        1.4   simonb 	uint32_t ctrdiff[4], startctr, endctr;
    137       1.11  gdamore 	uint8_t regc;
    138        1.1   simonb 	int i;
    139        1.1   simonb 
    140        1.1   simonb 	/* Disable interrupts first. */
    141        1.1   simonb 	bus_space_write_1(st, sh, 0, MC_REGB);
    142        1.1   simonb 	bus_space_write_1(st, sh, 1, MC_REGB_SQWE | MC_REGB_BINARY |
    143        1.1   simonb 	    MC_REGB_24HR);
    144        1.1   simonb 
    145        1.1   simonb 	/* Initialize for 16Hz. */
    146        1.1   simonb 	bus_space_write_1(st, sh, 0, MC_REGA);
    147        1.1   simonb 	bus_space_write_1(st, sh, 1, MC_BASE_32_KHz | MC_RATE_16_Hz);
    148        1.1   simonb 
    149        1.1   simonb 	/* Run the loop an extra time to prime the cache. */
    150        1.1   simonb 	for (i = 0; i < 4; i++) {
    151        1.1   simonb 		// led_display('h', 'z', '0' + i, ' ');
    152        1.1   simonb 
    153        1.1   simonb 		/* Enable the interrupt. */
    154        1.1   simonb 		bus_space_write_1(st, sh, 0, MC_REGB);
    155        1.1   simonb 		bus_space_write_1(st, sh, 1, MC_REGB_PIE | MC_REGB_SQWE |
    156        1.1   simonb 		    MC_REGB_BINARY | MC_REGB_24HR);
    157        1.1   simonb 
    158        1.1   simonb 		/* Go to REGC. */
    159        1.1   simonb 		bus_space_write_1(st, sh, 0, MC_REGC);
    160        1.1   simonb 
    161        1.1   simonb 		/* Wait for it to happen. */
    162        1.1   simonb 		startctr = mips3_cp0_count_read();
    163        1.1   simonb 		do {
    164        1.1   simonb 			regc = bus_space_read_1(st, sh, 1);
    165        1.1   simonb 			endctr = mips3_cp0_count_read();
    166        1.1   simonb 		} while ((regc & MC_REGC_IRQF) == 0);
    167        1.1   simonb 
    168        1.1   simonb 		/* Already ACK'd. */
    169        1.1   simonb 
    170        1.1   simonb 		/* Disable. */
    171        1.1   simonb 		bus_space_write_1(st, sh, 0, MC_REGB);
    172        1.1   simonb 		bus_space_write_1(st, sh, 1, MC_REGB_SQWE | MC_REGB_BINARY |
    173        1.1   simonb 		    MC_REGB_24HR);
    174        1.1   simonb 
    175        1.1   simonb 		ctrdiff[i] = endctr - startctr;
    176        1.1   simonb 	}
    177        1.1   simonb 
    178        1.1   simonb 	/* Compute the number of cycles per second. */
    179  1.19.28.1   bouyer 	ci->ci_cpu_freq = ((ctrdiff[2] + ctrdiff[3]) / 2) * 16/*Hz*/;
    180        1.1   simonb 
    181        1.1   simonb 	/* Compute the number of ticks for hz. */
    182  1.19.28.1   bouyer 	ci->ci_cycles_per_hz = (ci->ci_cpu_freq + hz / 2) / hz;
    183        1.1   simonb 
    184       1.19  tsutsui 	/* Compute the delay divisor. */
    185  1.19.28.1   bouyer 	ci->ci_divisor_delay = ((ci->ci_cpu_freq + 500000) / 1000000);
    186        1.2   simonb 
    187        1.2   simonb 	/*
    188        1.2   simonb 	 * Get correct cpu frequency if the CPU runs at twice the
    189        1.2   simonb 	 * external/cp0-count frequency.
    190        1.2   simonb 	 */
    191  1.19.28.1   bouyer 	ci->ci_cctr_freq = ci->ci_cpu_freq;
    192  1.19.28.1   bouyer 	if (mips_options.mips_cpu_flags & CPU_MIPS_DOUBLE_COUNT)
    193  1.19.28.1   bouyer 		ci->ci_cpu_freq *= 2;
    194        1.1   simonb 
    195        1.1   simonb #ifdef DEBUG
    196        1.4   simonb 	printf("Timer calibration: %lu cycles/sec [(%u, %u) * 16]\n",
    197  1.19.28.1   bouyer 	    ci->ci_cpu_freq, ctrdiff[2], ctrdiff[3]);
    198        1.1   simonb #endif
    199        1.1   simonb }
    200        1.1   simonb 
    201        1.1   simonb void *
    202        1.1   simonb evbmips_intr_establish(int irq, int (*func)(void *), void *arg)
    203        1.1   simonb {
    204        1.1   simonb 	struct evbmips_intrhand *ih;
    205        1.1   simonb 	int s;
    206        1.1   simonb 
    207        1.1   simonb 	ih = malloc(sizeof(*ih), M_DEVBUF, M_NOWAIT);
    208        1.1   simonb 	if (ih == NULL)
    209        1.1   simonb 		return (NULL);
    210        1.1   simonb 
    211        1.1   simonb 	ih->ih_func = func;
    212        1.1   simonb 	ih->ih_arg = arg;
    213        1.1   simonb 
    214        1.1   simonb 	s = splhigh();
    215        1.1   simonb 
    216        1.1   simonb 	/*
    217        1.1   simonb 	 * Link it into the tables.
    218        1.1   simonb 	 */
    219        1.1   simonb 	LIST_INSERT_HEAD(&malta_cpuintrs[0].cintr_list, ih, ih_q);
    220        1.1   simonb 
    221        1.1   simonb 	/* XXX - should check that MIPS_INT_MASK_0 is set... */
    222        1.1   simonb 
    223        1.1   simonb 	splx(s);
    224        1.1   simonb 
    225        1.1   simonb 	return (ih);
    226        1.1   simonb }
    227        1.1   simonb 
    228        1.1   simonb void
    229        1.1   simonb evbmips_intr_disestablish(void *arg)
    230        1.1   simonb {
    231        1.1   simonb 	struct evbmips_intrhand *ih = arg;
    232        1.1   simonb 	int s;
    233        1.1   simonb 
    234        1.1   simonb 	s = splhigh();
    235        1.1   simonb 
    236        1.1   simonb 	/*
    237        1.1   simonb 	 * First, remove it from the table.
    238        1.1   simonb 	 */
    239        1.1   simonb 	LIST_REMOVE(ih, ih_q);
    240        1.1   simonb 
    241        1.1   simonb 	/* XXX - disable MIPS_INT_MASK_0 if list is empty? */
    242        1.1   simonb 
    243        1.1   simonb 	splx(s);
    244        1.1   simonb 
    245        1.1   simonb 	free(ih, M_DEVBUF);
    246        1.1   simonb }
    247        1.1   simonb 
    248        1.1   simonb void
    249  1.19.28.1   bouyer evbmips_iointr(int ipl, vaddr_t pc, uint32_t ipending)
    250        1.1   simonb {
    251        1.1   simonb 
    252        1.5   simonb 	/* Check for error interrupts (SMI, GT64120) */
    253        1.1   simonb 	if (ipending & (MIPS_INT_MASK_1 | MIPS_INT_MASK_3)) {
    254        1.1   simonb 		if (ipending & MIPS_INT_MASK_1)
    255        1.1   simonb 			panic("piix4 SMI interrupt");
    256        1.1   simonb 		if (ipending & MIPS_INT_MASK_3)
    257        1.5   simonb 			panic("gt64120 error interrupt");
    258        1.1   simonb 	}
    259        1.1   simonb 
    260        1.1   simonb 	/*
    261        1.1   simonb 	 * Read the interrupt pending registers, mask them with the
    262        1.1   simonb 	 * ones we have enabled, and service them in order of decreasing
    263        1.1   simonb 	 * priority.
    264        1.1   simonb 	 */
    265        1.1   simonb 	if (ipending & MIPS_INT_MASK_0) {
    266  1.19.28.1   bouyer 		struct evbmips_intrhand *ih;
    267        1.1   simonb 		/* All interrupts are gated through MIPS HW interrupt 0 */
    268        1.1   simonb 		malta_cpuintrs[0].cintr_count.ev_count++;
    269        1.1   simonb 		LIST_FOREACH(ih, &malta_cpuintrs[0].cintr_list, ih_q)
    270        1.1   simonb 			(*ih->ih_func)(ih->ih_arg);
    271        1.1   simonb 	}
    272        1.1   simonb }
    273        1.1   simonb 
    274        1.1   simonb /*
    275        1.1   simonb  * YAMON configures pa_intrline correctly (so far), so we trust it to DTRT
    276        1.1   simonb  * in the future...
    277        1.1   simonb  */
    278        1.1   simonb #undef YAMON_IRQ_MAP_BAD
    279        1.1   simonb 
    280        1.1   simonb /*
    281        1.1   simonb  * PCI interrupt support
    282        1.1   simonb  */
    283        1.1   simonb static int
    284        1.1   simonb malta_pci_intr_map(struct pci_attach_args *pa, pci_intr_handle_t *ihp)
    285        1.1   simonb {
    286        1.1   simonb #ifdef YAMON_IRQ_MAP_BAD
    287        1.7   simonb 	static const int pciirqmap[12/*device*/][4/*pin*/] = {
    288        1.1   simonb 		{ -1, -1, -1, 11 },	/* 10: USB */
    289        1.1   simonb 		{ 10, -1, -1, -1 },	/* 11: Ethernet */
    290        1.1   simonb 		{ 11, -1, -1, -1 },	/* 12: Audio */
    291        1.1   simonb 		{ -1, -1, -1, -1 },	/* 13: not used */
    292        1.1   simonb 		{ -1, -1, -1, -1 },	/* 14: not used */
    293        1.1   simonb 		{ -1, -1, -1, -1 },	/* 15: not used */
    294        1.1   simonb 		{ -1, -1, -1, -1 },	/* 16: not used */
    295        1.1   simonb 		{ -1, -1, -1, -1 },	/* 17: Core card(?) */
    296        1.1   simonb 		{ 10, 10, 11, 11 },	/* 18: PCI Slot 1 */
    297        1.1   simonb 		{ 10, 11, 11, 10 },	/* 19: PCI Slot 2 */
    298        1.1   simonb 		{ 11, 11, 10, 10 },	/* 20: PCI Slot 3 */
    299        1.1   simonb 		{ 11, 10, 10, 11 },	/* 21: PCI Slot 4 */
    300        1.1   simonb 	};
    301        1.1   simonb 	int buspin, device, irq;
    302        1.1   simonb #else	/* !YAMON_IRQ_MAP_BAD */
    303        1.1   simonb 	int buspin;
    304        1.1   simonb #endif	/* !YAMON_IRQ_MAP_BAD */
    305        1.1   simonb 
    306        1.1   simonb 	buspin = pa->pa_intrpin;
    307        1.1   simonb 
    308        1.1   simonb 	if (buspin == 0) {
    309        1.1   simonb 		/* No IRQ used. */
    310        1.1   simonb 		return (1);
    311        1.1   simonb 	}
    312        1.1   simonb 
    313        1.1   simonb 	if (buspin > 4) {
    314        1.1   simonb 		printf("malta_pci_intr_map: bad interrupt pin %d\n", buspin);
    315        1.1   simonb 		return (1);
    316        1.1   simonb 	}
    317        1.1   simonb 
    318        1.1   simonb #ifdef YAMON_IRQ_MAP_BAD
    319        1.1   simonb 	pci_decompose_tag(pa->pa_pc, pa->pa_intrtag, NULL, &device, NULL);
    320        1.1   simonb 
    321        1.1   simonb 	if (device < 10 || device > 21) {
    322        1.1   simonb 		printf("malta_pci_intr_map: bad device %d\n", device);
    323        1.1   simonb 		return (1);
    324        1.1   simonb 	}
    325        1.1   simonb 
    326        1.1   simonb 	irq = pciirqmap[device - 10][buspin - 1];
    327        1.1   simonb 	if (irq == -1) {
    328        1.1   simonb 		printf("malta_pci_intr_map: no mapping for device %d pin %d\n",
    329        1.1   simonb 		    device, buspin);
    330        1.1   simonb 		return (1);
    331        1.1   simonb 	}
    332        1.1   simonb 
    333        1.1   simonb 	*ihp = irq;
    334        1.1   simonb #else	/* !YAMON_IRQ_MAP_BAD */
    335        1.1   simonb 	*ihp = pa->pa_intrline;
    336        1.1   simonb #endif	/* !YAMON_IRQ_MAP_BAD */
    337        1.1   simonb 	return (0);
    338        1.1   simonb }
    339        1.1   simonb 
    340        1.1   simonb static const char *
    341        1.1   simonb malta_pci_intr_string(void *v, pci_intr_handle_t irq)
    342        1.1   simonb {
    343        1.1   simonb 
    344        1.1   simonb 	return (isa_intr_string(pcib_ic, irq));
    345        1.1   simonb }
    346        1.1   simonb 
    347        1.1   simonb static const struct evcnt *
    348        1.1   simonb malta_pci_intr_evcnt(void *v, pci_intr_handle_t irq)
    349        1.1   simonb {
    350        1.1   simonb 
    351        1.1   simonb 	return (isa_intr_evcnt(pcib_ic, irq));
    352        1.1   simonb }
    353        1.1   simonb 
    354        1.1   simonb static void *
    355        1.1   simonb malta_pci_intr_establish(void *v, pci_intr_handle_t irq, int level,
    356        1.1   simonb     int (*func)(void *), void *arg)
    357        1.1   simonb {
    358        1.1   simonb 
    359        1.1   simonb 	return (isa_intr_establish(pcib_ic, irq, IST_LEVEL, level, func, arg));
    360        1.1   simonb }
    361        1.1   simonb 
    362        1.1   simonb static void
    363        1.1   simonb malta_pci_intr_disestablish(void *v, void *arg)
    364        1.1   simonb {
    365        1.1   simonb 
    366        1.1   simonb 	return (isa_intr_disestablish(pcib_ic, arg));
    367        1.1   simonb }
    368        1.1   simonb 
    369        1.1   simonb static void
    370        1.1   simonb malta_pci_conf_interrupt(void *v, int bus, int dev, int func, int swiz,
    371        1.1   simonb     int *iline)
    372        1.1   simonb {
    373        1.1   simonb 
    374        1.1   simonb 	/*
    375        1.1   simonb 	 * We actually don't need to do anything; everything is handled
    376        1.1   simonb 	 * in pci_intr_map().
    377        1.1   simonb 	 */
    378        1.1   simonb 	*iline = 0;
    379        1.1   simonb }
    380        1.1   simonb 
    381        1.1   simonb void *
    382        1.1   simonb malta_pciide_compat_intr_establish(void *v, struct device *dev,
    383        1.1   simonb     struct pci_attach_args *pa, int chan, int (*func)(void *), void *arg)
    384        1.1   simonb {
    385        1.1   simonb 	pci_chipset_tag_t pc = pa->pa_pc;
    386        1.1   simonb 	void *cookie;
    387        1.1   simonb 	int bus, irq;
    388        1.1   simonb 
    389        1.1   simonb 	pci_decompose_tag(pc, pa->pa_tag, &bus, NULL, NULL);
    390        1.1   simonb 
    391        1.1   simonb 	/*
    392        1.1   simonb 	 * If this isn't PCI bus #0, all bets are off.
    393        1.1   simonb 	 */
    394        1.1   simonb 	if (bus != 0)
    395        1.1   simonb 		return (NULL);
    396        1.1   simonb 
    397        1.1   simonb 	irq = PCIIDE_COMPAT_IRQ(chan);
    398        1.1   simonb 	cookie = isa_intr_establish(pcib_ic, irq, IST_EDGE, IPL_BIO, func, arg);
    399        1.1   simonb 	if (cookie == NULL)
    400        1.1   simonb 		return (NULL);
    401        1.1   simonb 	printf("%s: %s channel interrupting at %s\n", dev->dv_xname,
    402        1.1   simonb 	    PCIIDE_CHANNEL_NAME(chan), malta_pci_intr_string(v, irq));
    403        1.1   simonb 	return (cookie);
    404        1.1   simonb }
    405