1 /* ASB2305 PCI support
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  * Derived from arch/i386/kernel/pci-pc.c
6  *	(c) 1999--2000 Martin Mares <mj@suse.cz>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public Licence
10  * as published by the Free Software Foundation; either version
11  * 2 of the Licence, or (at your option) any later version.
12  */
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/pci.h>
17 #include <linux/init.h>
18 #include <linux/ioport.h>
19 #include <linux/delay.h>
20 #include <asm/io.h>
21 #include "pci-asb2305.h"
22 
23 unsigned int pci_probe = 1;
24 
25 int pcibios_last_bus = -1;
26 struct pci_bus *pci_root_bus;
27 struct pci_ops *pci_root_ops;
28 
29 /*
30  * The accessible PCI window does not cover the entire CPU address space, but
31  * there are devices we want to access outside of that window, so we need to
32  * insert specific PCI bus resources instead of using the platform-level bus
33  * resources directly for the PCI root bus.
34  *
35  * These are configured and inserted by pcibios_init() and are attached to the
36  * root bus by pcibios_fixup_bus().
37  */
38 static struct resource pci_ioport_resource = {
39 	.name	= "PCI IO",
40 	.start	= 0xbe000000,
41 	.end	= 0xbe03ffff,
42 	.flags	= IORESOURCE_IO,
43 };
44 
45 static struct resource pci_iomem_resource = {
46 	.name	= "PCI mem",
47 	.start	= 0xb8000000,
48 	.end	= 0xbbffffff,
49 	.flags	= IORESOURCE_MEM,
50 };
51 
52 /*
53  * Functions for accessing PCI configuration space
54  */
55 
56 #define CONFIG_CMD(bus, devfn, where) \
57 	(0x80000000 | (bus->number << 16) | (devfn << 8) | (where & ~3))
58 
59 #define MEM_PAGING_REG	(*(volatile __u32 *) 0xBFFFFFF4)
60 #define CONFIG_ADDRESS	(*(volatile __u32 *) 0xBFFFFFF8)
61 #define CONFIG_DATAL(X)	(*(volatile __u32 *) 0xBFFFFFFC)
62 #define CONFIG_DATAW(X)	(*(volatile __u16 *) (0xBFFFFFFC + ((X) & 2)))
63 #define CONFIG_DATAB(X)	(*(volatile __u8  *) (0xBFFFFFFC + ((X) & 3)))
64 
65 #define BRIDGEREGB(X)	(*(volatile __u8  *) (0xBE040000 + (X)))
66 #define BRIDGEREGW(X)	(*(volatile __u16 *) (0xBE040000 + (X)))
67 #define BRIDGEREGL(X)	(*(volatile __u32 *) (0xBE040000 + (X)))
68 
__query(const struct pci_bus * bus,unsigned int devfn)69 static inline int __query(const struct pci_bus *bus, unsigned int devfn)
70 {
71 #if 0
72 	return bus->number == 0 && (devfn == PCI_DEVFN(0, 0));
73 	return bus->number == 1;
74 	return bus->number == 0 &&
75 		(devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(3, 0));
76 #endif
77 	return 1;
78 }
79 
80 /*
81  * translate Linuxcentric addresses to PCI bus addresses
82  */
pcibios_resource_to_bus(struct pci_dev * dev,struct pci_bus_region * region,struct resource * res)83 void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
84 			     struct resource *res)
85 {
86 	if (res->flags & IORESOURCE_IO) {
87 		region->start = (res->start & 0x00ffffff);
88 		region->end   = (res->end   & 0x00ffffff);
89 	}
90 
91 	if (res->flags & IORESOURCE_MEM) {
92 		region->start = (res->start & 0x03ffffff) | MEM_PAGING_REG;
93 		region->end   = (res->end   & 0x03ffffff) | MEM_PAGING_REG;
94 	}
95 
96 #if 0
97 	printk(KERN_DEBUG "RES->BUS: %lx-%lx => %lx-%lx\n",
98 	       res->start, res->end, region->start, region->end);
99 #endif
100 }
101 EXPORT_SYMBOL(pcibios_resource_to_bus);
102 
103 /*
104  * translate PCI bus addresses to Linuxcentric addresses
105  */
pcibios_bus_to_resource(struct pci_dev * dev,struct resource * res,struct pci_bus_region * region)106 void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
107 			     struct pci_bus_region *region)
108 {
109 	if (res->flags & IORESOURCE_IO) {
110 		res->start = (region->start & 0x00ffffff) | 0xbe000000;
111 		res->end   = (region->end   & 0x00ffffff) | 0xbe000000;
112 	}
113 
114 	if (res->flags & IORESOURCE_MEM) {
115 		res->start = (region->start & 0x03ffffff) | 0xb8000000;
116 		res->end   = (region->end   & 0x03ffffff) | 0xb8000000;
117 	}
118 
119 #if 0
120 	printk(KERN_INFO "BUS->RES: %lx-%lx => %lx-%lx\n",
121 	       region->start, region->end, res->start, res->end);
122 #endif
123 }
124 EXPORT_SYMBOL(pcibios_bus_to_resource);
125 
126 /*
127  *
128  */
pci_ampci_read_config_byte(struct pci_bus * bus,unsigned int devfn,int where,u32 * _value)129 static int pci_ampci_read_config_byte(struct pci_bus *bus, unsigned int devfn,
130 				      int where, u32 *_value)
131 {
132 	u32 rawval, value;
133 
134 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
135 		value = BRIDGEREGB(where);
136 		__pcbdebug("=> %02hx", &BRIDGEREGL(where), value);
137 	} else {
138 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
139 		rawval = CONFIG_ADDRESS;
140 		value = CONFIG_DATAB(where);
141 		if (__query(bus, devfn))
142 			__pcidebug("=> %02hx", bus, devfn, where, value);
143 	}
144 
145 	*_value = value;
146 	return PCIBIOS_SUCCESSFUL;
147 }
148 
pci_ampci_read_config_word(struct pci_bus * bus,unsigned int devfn,int where,u32 * _value)149 static int pci_ampci_read_config_word(struct pci_bus *bus, unsigned int devfn,
150 				      int where, u32 *_value)
151 {
152 	u32 rawval, value;
153 
154 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
155 		value = BRIDGEREGW(where);
156 		__pcbdebug("=> %04hx", &BRIDGEREGL(where), value);
157 	} else {
158 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
159 		rawval = CONFIG_ADDRESS;
160 		value = CONFIG_DATAW(where);
161 		if (__query(bus, devfn))
162 			__pcidebug("=> %04hx", bus, devfn, where, value);
163 	}
164 
165 	*_value = value;
166 	return PCIBIOS_SUCCESSFUL;
167 }
168 
pci_ampci_read_config_dword(struct pci_bus * bus,unsigned int devfn,int where,u32 * _value)169 static int pci_ampci_read_config_dword(struct pci_bus *bus, unsigned int devfn,
170 				       int where, u32 *_value)
171 {
172 	u32 rawval, value;
173 
174 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
175 		value = BRIDGEREGL(where);
176 		__pcbdebug("=> %08x", &BRIDGEREGL(where), value);
177 	} else {
178 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
179 		rawval = CONFIG_ADDRESS;
180 		value = CONFIG_DATAL(where);
181 		if (__query(bus, devfn))
182 			__pcidebug("=> %08x", bus, devfn, where, value);
183 	}
184 
185 	*_value = value;
186 	return PCIBIOS_SUCCESSFUL;
187 }
188 
pci_ampci_write_config_byte(struct pci_bus * bus,unsigned int devfn,int where,u8 value)189 static int pci_ampci_write_config_byte(struct pci_bus *bus, unsigned int devfn,
190 				       int where, u8 value)
191 {
192 	u32 rawval;
193 
194 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
195 		__pcbdebug("<= %02x", &BRIDGEREGB(where), value);
196 		BRIDGEREGB(where) = value;
197 	} else {
198 		if (bus->number == 0 &&
199 		    (devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(3, 0))
200 		    )
201 			__pcidebug("<= %02x", bus, devfn, where, value);
202 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
203 		rawval = CONFIG_ADDRESS;
204 		CONFIG_DATAB(where) = value;
205 	}
206 	return PCIBIOS_SUCCESSFUL;
207 }
208 
pci_ampci_write_config_word(struct pci_bus * bus,unsigned int devfn,int where,u16 value)209 static int pci_ampci_write_config_word(struct pci_bus *bus, unsigned int devfn,
210 				       int where, u16 value)
211 {
212 	u32 rawval;
213 
214 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
215 		__pcbdebug("<= %04hx", &BRIDGEREGW(where), value);
216 		BRIDGEREGW(where) = value;
217 	} else {
218 		if (__query(bus, devfn))
219 			__pcidebug("<= %04hx", bus, devfn, where, value);
220 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
221 		rawval = CONFIG_ADDRESS;
222 		CONFIG_DATAW(where) = value;
223 	}
224 	return PCIBIOS_SUCCESSFUL;
225 }
226 
pci_ampci_write_config_dword(struct pci_bus * bus,unsigned int devfn,int where,u32 value)227 static int pci_ampci_write_config_dword(struct pci_bus *bus, unsigned int devfn,
228 					int where, u32 value)
229 {
230 	u32 rawval;
231 
232 	if (bus->number == 0 && devfn == PCI_DEVFN(0, 0)) {
233 		__pcbdebug("<= %08x", &BRIDGEREGL(where), value);
234 		BRIDGEREGL(where) = value;
235 	} else {
236 		if (__query(bus, devfn))
237 			__pcidebug("<= %08x", bus, devfn, where, value);
238 		CONFIG_ADDRESS = CONFIG_CMD(bus, devfn, where);
239 		rawval = CONFIG_ADDRESS;
240 		CONFIG_DATAL(where) = value;
241 	}
242 	return PCIBIOS_SUCCESSFUL;
243 }
244 
pci_ampci_read_config(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 * val)245 static int pci_ampci_read_config(struct pci_bus *bus, unsigned int devfn,
246 				 int where, int size, u32 *val)
247 {
248 	switch (size) {
249 	case 1:
250 		return pci_ampci_read_config_byte(bus, devfn, where, val);
251 	case 2:
252 		return pci_ampci_read_config_word(bus, devfn, where, val);
253 	case 4:
254 		return pci_ampci_read_config_dword(bus, devfn, where, val);
255 	default:
256 		BUG();
257 		return -EOPNOTSUPP;
258 	}
259 }
260 
pci_ampci_write_config(struct pci_bus * bus,unsigned int devfn,int where,int size,u32 val)261 static int pci_ampci_write_config(struct pci_bus *bus, unsigned int devfn,
262 				  int where, int size, u32 val)
263 {
264 	switch (size) {
265 	case 1:
266 		return pci_ampci_write_config_byte(bus, devfn, where, val);
267 	case 2:
268 		return pci_ampci_write_config_word(bus, devfn, where, val);
269 	case 4:
270 		return pci_ampci_write_config_dword(bus, devfn, where, val);
271 	default:
272 		BUG();
273 		return -EOPNOTSUPP;
274 	}
275 }
276 
277 static struct pci_ops pci_direct_ampci = {
278 	pci_ampci_read_config,
279 	pci_ampci_write_config,
280 };
281 
282 /*
283  * Before we decide to use direct hardware access mechanisms, we try to do some
284  * trivial checks to ensure it at least _seems_ to be working -- we just test
285  * whether bus 00 contains a host bridge (this is similar to checking
286  * techniques used in XFree86, but ours should be more reliable since we
287  * attempt to make use of direct access hints provided by the PCI BIOS).
288  *
289  * This should be close to trivial, but it isn't, because there are buggy
290  * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
291  */
pci_sanity_check(struct pci_ops * o)292 static int __init pci_sanity_check(struct pci_ops *o)
293 {
294 	struct pci_bus bus;		/* Fake bus and device */
295 	u32 x;
296 
297 	bus.number = 0;
298 
299 	if ((!o->read(&bus, 0, PCI_CLASS_DEVICE, 2, &x) &&
300 	     (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)) ||
301 	    (!o->read(&bus, 0, PCI_VENDOR_ID, 2, &x) &&
302 	     (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)))
303 		return 1;
304 
305 	printk(KERN_ERR "PCI: Sanity check failed\n");
306 	return 0;
307 }
308 
pci_check_direct(void)309 static int __init pci_check_direct(void)
310 {
311 	unsigned long flags;
312 
313 	local_irq_save(flags);
314 
315 	/*
316 	 * Check if access works.
317 	 */
318 	if (pci_sanity_check(&pci_direct_ampci)) {
319 		local_irq_restore(flags);
320 		printk(KERN_INFO "PCI: Using configuration ampci\n");
321 		request_mem_region(0xBE040000, 256, "AMPCI bridge");
322 		request_mem_region(0xBFFFFFF4, 12, "PCI ampci");
323 		request_mem_region(0xBC000000, 32 * 1024 * 1024, "PCI SRAM");
324 		return 0;
325 	}
326 
327 	local_irq_restore(flags);
328 	return -ENODEV;
329 }
330 
is_valid_resource(struct pci_dev * dev,int idx)331 static int __devinit is_valid_resource(struct pci_dev *dev, int idx)
332 {
333 	unsigned int i, type_mask = IORESOURCE_IO | IORESOURCE_MEM;
334 	struct resource *devr = &dev->resource[idx], *busr;
335 
336 	if (dev->bus) {
337 		pci_bus_for_each_resource(dev->bus, busr, i) {
338 			if (!busr || (busr->flags ^ devr->flags) & type_mask)
339 				continue;
340 
341 			if (devr->start &&
342 			    devr->start >= busr->start &&
343 			    devr->end <= busr->end)
344 				return 1;
345 		}
346 	}
347 
348 	return 0;
349 }
350 
pcibios_fixup_device_resources(struct pci_dev * dev)351 static void __devinit pcibios_fixup_device_resources(struct pci_dev *dev)
352 {
353 	struct pci_bus_region region;
354 	int i;
355 	int limit;
356 
357 	if (dev->bus->number != 0)
358 		return;
359 
360 	limit = (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) ?
361 		PCI_BRIDGE_RESOURCES : PCI_NUM_RESOURCES;
362 
363 	for (i = 0; i < limit; i++) {
364 		if (!dev->resource[i].flags)
365 			continue;
366 
367 		region.start = dev->resource[i].start;
368 		region.end = dev->resource[i].end;
369 		pcibios_bus_to_resource(dev, &dev->resource[i], &region);
370 		if (is_valid_resource(dev, i))
371 			pci_claim_resource(dev, i);
372 	}
373 }
374 
375 /*
376  *  Called after each bus is probed, but before its children
377  *  are examined.
378  */
pcibios_fixup_bus(struct pci_bus * bus)379 void __devinit pcibios_fixup_bus(struct pci_bus *bus)
380 {
381 	struct pci_dev *dev;
382 
383 	if (bus->number == 0) {
384 		bus->resource[0] = &pci_ioport_resource;
385 		bus->resource[1] = &pci_iomem_resource;
386 	}
387 
388 	if (bus->self) {
389 		pci_read_bridge_bases(bus);
390 		pcibios_fixup_device_resources(bus->self);
391 	}
392 
393 	list_for_each_entry(dev, &bus->devices, bus_list)
394 		pcibios_fixup_device_resources(dev);
395 }
396 
397 /*
398  * Initialization. Try all known PCI access methods. Note that we support
399  * using both PCI BIOS and direct access: in such cases, we use I/O ports
400  * to access config space, but we still keep BIOS order of cards to be
401  * compatible with 2.0.X. This should go away some day.
402  */
pcibios_init(void)403 static int __init pcibios_init(void)
404 {
405 	ioport_resource.start	= 0xA0000000;
406 	ioport_resource.end	= 0xDFFFFFFF;
407 	iomem_resource.start	= 0xA0000000;
408 	iomem_resource.end	= 0xDFFFFFFF;
409 
410 	if (insert_resource(&iomem_resource, &pci_iomem_resource) < 0)
411 		panic("Unable to insert PCI IOMEM resource\n");
412 	if (insert_resource(&ioport_resource, &pci_ioport_resource) < 0)
413 		panic("Unable to insert PCI IOPORT resource\n");
414 
415 	if (!pci_probe)
416 		return 0;
417 
418 	if (pci_check_direct() < 0) {
419 		printk(KERN_WARNING "PCI: No PCI bus detected\n");
420 		return 0;
421 	}
422 
423 	printk(KERN_INFO "PCI: Probing PCI hardware [mempage %08x]\n",
424 	       MEM_PAGING_REG);
425 
426 	pci_root_bus = pci_scan_bus(0, &pci_direct_ampci, NULL);
427 
428 	pcibios_irq_init();
429 	pcibios_fixup_irqs();
430 	pcibios_resource_survey();
431 	return 0;
432 }
433 
434 arch_initcall(pcibios_init);
435 
pcibios_setup(char * str)436 char *__init pcibios_setup(char *str)
437 {
438 	if (!strcmp(str, "off")) {
439 		pci_probe = 0;
440 		return NULL;
441 
442 	} else if (!strncmp(str, "lastbus=", 8)) {
443 		pcibios_last_bus = simple_strtol(str+8, NULL, 0);
444 		return NULL;
445 	}
446 
447 	return str;
448 }
449 
pcibios_enable_device(struct pci_dev * dev,int mask)450 int pcibios_enable_device(struct pci_dev *dev, int mask)
451 {
452 	int err;
453 
454 	err = pci_enable_resources(dev, mask);
455 	if (err == 0)
456 		pcibios_enable_irq(dev);
457 	return err;
458 }
459 
460 /*
461  * disable the ethernet chipset
462  */
unit_disable_pcnet(struct pci_bus * bus,struct pci_ops * o)463 static void __init unit_disable_pcnet(struct pci_bus *bus, struct pci_ops *o)
464 {
465 	u32 x;
466 
467 	bus->number = 0;
468 
469 	o->read (bus, PCI_DEVFN(2, 0), PCI_VENDOR_ID,		4, &x);
470 	o->read (bus, PCI_DEVFN(2, 0), PCI_COMMAND,		2, &x);
471 	x |= PCI_COMMAND_MASTER |
472 		PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
473 		PCI_COMMAND_SERR | PCI_COMMAND_PARITY;
474 	o->write(bus, PCI_DEVFN(2, 0), PCI_COMMAND,		2, x);
475 	o->read (bus, PCI_DEVFN(2, 0), PCI_COMMAND,		2, &x);
476 	o->write(bus, PCI_DEVFN(2, 0), PCI_BASE_ADDRESS_0,	4, 0x00030001);
477 	o->read (bus, PCI_DEVFN(2, 0), PCI_BASE_ADDRESS_0,	4, &x);
478 
479 #define RDP (*(volatile u32 *) 0xBE030010)
480 #define RAP (*(volatile u32 *) 0xBE030014)
481 #define __set_RAP(X) do { RAP = (X); x = RAP; } while (0)
482 #define __set_RDP(X) do { RDP = (X); x = RDP; } while (0)
483 #define __get_RDP() ({ RDP & 0xffff; })
484 
485 	__set_RAP(0);
486 	__set_RDP(0x0004);	/* CSR0 = STOP */
487 
488 	__set_RAP(88);		/* check CSR88 indicates an Am79C973 */
489 	BUG_ON(__get_RDP() != 0x5003);
490 
491 	for (x = 0; x < 100; x++)
492 		asm volatile("nop");
493 
494 	__set_RDP(0x0004);	/* CSR0 = STOP */
495 }
496 
497 /*
498  * initialise the unit hardware
499  */
unit_pci_init(void)500 asmlinkage void __init unit_pci_init(void)
501 {
502 	struct pci_bus bus;		/* Fake bus and device */
503 	struct pci_ops *o = &pci_direct_ampci;
504 	u32 x;
505 
506 	set_intr_level(XIRQ1, NUM2GxICR_LEVEL(CONFIG_PCI_IRQ_LEVEL));
507 
508 	memset(&bus, 0, sizeof(bus));
509 
510 	MEM_PAGING_REG = 0xE8000000;
511 
512 	/* we need to set up the bridge _now_ or we won't be able to access the
513 	 * PCI config registers
514 	 */
515 	BRIDGEREGW(PCI_COMMAND) |=
516 		PCI_COMMAND_SERR | PCI_COMMAND_PARITY |
517 		PCI_COMMAND_MEMORY | PCI_COMMAND_IO | PCI_COMMAND_MASTER;
518 	BRIDGEREGW(PCI_STATUS)		= 0xF800;
519 	BRIDGEREGB(PCI_LATENCY_TIMER)	= 0x10;
520 	BRIDGEREGL(PCI_BASE_ADDRESS_0)	= 0x80000000;
521 	BRIDGEREGB(PCI_INTERRUPT_LINE)	= 1;
522 	BRIDGEREGL(0x48)		= 0x98000000;	/* AMPCI base addr */
523 	BRIDGEREGB(0x41)		= 0x00;		/* secondary bus
524 							 * number */
525 	BRIDGEREGB(0x42)		= 0x01;		/* subordinate bus
526 							 * number */
527 	BRIDGEREGB(0x44)		= 0x01;
528 	BRIDGEREGL(0x50)		= 0x00000001;
529 	BRIDGEREGL(0x58)		= 0x00001002;
530 	BRIDGEREGL(0x5C)		= 0x00000011;
531 
532 	/* we also need to set up the PCI-PCI bridge */
533 	bus.number = 0;
534 
535 	/* IO: 0x00000000-0x00020000 */
536 	o->read (&bus, PCI_DEVFN(3, 0), PCI_COMMAND,		2, &x);
537 	x |= PCI_COMMAND_MASTER |
538 		PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
539 		PCI_COMMAND_SERR | PCI_COMMAND_PARITY;
540 	o->write(&bus, PCI_DEVFN(3, 0), PCI_COMMAND,		2, x);
541 
542 	o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,		1, &x);
543 	o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,	4, &x);
544 	o->read (&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,	4, &x);
545 	o->read (&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,	4, &x);
546 
547 	o->write(&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,		1, 0x01);
548 	o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE,		1, &x);
549 	o->write(&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,	4, 0x00020000);
550 	o->read (&bus, PCI_DEVFN(3, 0), PCI_IO_BASE_UPPER16,	4, &x);
551 	o->write(&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,	4, 0xEBB0EA00);
552 	o->read (&bus, PCI_DEVFN(3, 0), PCI_MEMORY_BASE,	4, &x);
553 	o->write(&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,	4, 0xE9F0E800);
554 	o->read (&bus, PCI_DEVFN(3, 0), PCI_PREF_MEMORY_BASE,	4, &x);
555 
556 	unit_disable_pcnet(&bus, o);
557 }
558