xref: /linux/drivers/pci/pci.c (revision 20d0021394c1b070bf04b22c5bc8fdb437edd4c5)
1 /*
2  *	$Id: pci.c,v 1.91 1999/01/21 13:34:01 davem Exp $
3  *
4  *	PCI Bus Services, see include/linux/pci.h for further explanation.
5  *
6  *	Copyright 1993 -- 1997 Drew Eckhardt, Frederic Potter,
7  *	David Mosberger-Tang
8  *
9  *	Copyright 1997 -- 2000 Martin Mares <mj@ucw.cz>
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/delay.h>
14 #include <linux/init.h>
15 #include <linux/pci.h>
16 #include <linux/module.h>
17 #include <linux/spinlock.h>
18 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
19 #include "pci.h"
20 
21 
22 /**
23  * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
24  * @bus: pointer to PCI bus structure to search
25  *
26  * Given a PCI bus, returns the highest PCI bus number present in the set
27  * including the given PCI bus and its list of child PCI buses.
28  */
29 unsigned char __devinit
30 pci_bus_max_busnr(struct pci_bus* bus)
31 {
32 	struct list_head *tmp;
33 	unsigned char max, n;
34 
35 	max = bus->number;
36 	list_for_each(tmp, &bus->children) {
37 		n = pci_bus_max_busnr(pci_bus_b(tmp));
38 		if(n > max)
39 			max = n;
40 	}
41 	return max;
42 }
43 
44 /**
45  * pci_max_busnr - returns maximum PCI bus number
46  *
47  * Returns the highest PCI bus number present in the system global list of
48  * PCI buses.
49  */
50 unsigned char __devinit
51 pci_max_busnr(void)
52 {
53 	struct pci_bus *bus = NULL;
54 	unsigned char max, n;
55 
56 	max = 0;
57 	while ((bus = pci_find_next_bus(bus)) != NULL) {
58 		n = pci_bus_max_busnr(bus);
59 		if(n > max)
60 			max = n;
61 	}
62 	return max;
63 }
64 
65 static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_type, int cap)
66 {
67 	u16 status;
68 	u8 pos, id;
69 	int ttl = 48;
70 
71 	pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
72 	if (!(status & PCI_STATUS_CAP_LIST))
73 		return 0;
74 
75 	switch (hdr_type) {
76 	case PCI_HEADER_TYPE_NORMAL:
77 	case PCI_HEADER_TYPE_BRIDGE:
78 		pci_bus_read_config_byte(bus, devfn, PCI_CAPABILITY_LIST, &pos);
79 		break;
80 	case PCI_HEADER_TYPE_CARDBUS:
81 		pci_bus_read_config_byte(bus, devfn, PCI_CB_CAPABILITY_LIST, &pos);
82 		break;
83 	default:
84 		return 0;
85 	}
86 	while (ttl-- && pos >= 0x40) {
87 		pos &= ~3;
88 		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID, &id);
89 		if (id == 0xff)
90 			break;
91 		if (id == cap)
92 			return pos;
93 		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_NEXT, &pos);
94 	}
95 	return 0;
96 }
97 
98 /**
99  * pci_find_capability - query for devices' capabilities
100  * @dev: PCI device to query
101  * @cap: capability code
102  *
103  * Tell if a device supports a given PCI capability.
104  * Returns the address of the requested capability structure within the
105  * device's PCI configuration space or 0 in case the device does not
106  * support it.  Possible values for @cap:
107  *
108  *  %PCI_CAP_ID_PM           Power Management
109  *  %PCI_CAP_ID_AGP          Accelerated Graphics Port
110  *  %PCI_CAP_ID_VPD          Vital Product Data
111  *  %PCI_CAP_ID_SLOTID       Slot Identification
112  *  %PCI_CAP_ID_MSI          Message Signalled Interrupts
113  *  %PCI_CAP_ID_CHSWP        CompactPCI HotSwap
114  *  %PCI_CAP_ID_PCIX         PCI-X
115  *  %PCI_CAP_ID_EXP          PCI Express
116  */
117 int pci_find_capability(struct pci_dev *dev, int cap)
118 {
119 	return __pci_bus_find_cap(dev->bus, dev->devfn, dev->hdr_type, cap);
120 }
121 
122 /**
123  * pci_bus_find_capability - query for devices' capabilities
124  * @bus:   the PCI bus to query
125  * @devfn: PCI device to query
126  * @cap:   capability code
127  *
128  * Like pci_find_capability() but works for pci devices that do not have a
129  * pci_dev structure set up yet.
130  *
131  * Returns the address of the requested capability structure within the
132  * device's PCI configuration space or 0 in case the device does not
133  * support it.
134  */
135 int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap)
136 {
137 	u8 hdr_type;
138 
139 	pci_bus_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type);
140 
141 	return __pci_bus_find_cap(bus, devfn, hdr_type & 0x7f, cap);
142 }
143 
144 /**
145  * pci_find_ext_capability - Find an extended capability
146  * @dev: PCI device to query
147  * @cap: capability code
148  *
149  * Returns the address of the requested extended capability structure
150  * within the device's PCI configuration space or 0 if the device does
151  * not support it.  Possible values for @cap:
152  *
153  *  %PCI_EXT_CAP_ID_ERR		Advanced Error Reporting
154  *  %PCI_EXT_CAP_ID_VC		Virtual Channel
155  *  %PCI_EXT_CAP_ID_DSN		Device Serial Number
156  *  %PCI_EXT_CAP_ID_PWR		Power Budgeting
157  */
158 int pci_find_ext_capability(struct pci_dev *dev, int cap)
159 {
160 	u32 header;
161 	int ttl = 480; /* 3840 bytes, minimum 8 bytes per capability */
162 	int pos = 0x100;
163 
164 	if (dev->cfg_size <= 256)
165 		return 0;
166 
167 	if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
168 		return 0;
169 
170 	/*
171 	 * If we have no capabilities, this is indicated by cap ID,
172 	 * cap version and next pointer all being 0.
173 	 */
174 	if (header == 0)
175 		return 0;
176 
177 	while (ttl-- > 0) {
178 		if (PCI_EXT_CAP_ID(header) == cap)
179 			return pos;
180 
181 		pos = PCI_EXT_CAP_NEXT(header);
182 		if (pos < 0x100)
183 			break;
184 
185 		if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
186 			break;
187 	}
188 
189 	return 0;
190 }
191 
192 /**
193  * pci_find_parent_resource - return resource region of parent bus of given region
194  * @dev: PCI device structure contains resources to be searched
195  * @res: child resource record for which parent is sought
196  *
197  *  For given resource region of given device, return the resource
198  *  region of parent bus the given region is contained in or where
199  *  it should be allocated from.
200  */
201 struct resource *
202 pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
203 {
204 	const struct pci_bus *bus = dev->bus;
205 	int i;
206 	struct resource *best = NULL;
207 
208 	for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
209 		struct resource *r = bus->resource[i];
210 		if (!r)
211 			continue;
212 		if (res->start && !(res->start >= r->start && res->end <= r->end))
213 			continue;	/* Not contained */
214 		if ((res->flags ^ r->flags) & (IORESOURCE_IO | IORESOURCE_MEM))
215 			continue;	/* Wrong type */
216 		if (!((res->flags ^ r->flags) & IORESOURCE_PREFETCH))
217 			return r;	/* Exact match */
218 		if ((res->flags & IORESOURCE_PREFETCH) && !(r->flags & IORESOURCE_PREFETCH))
219 			best = r;	/* Approximating prefetchable by non-prefetchable */
220 	}
221 	return best;
222 }
223 
224 /**
225  * pci_set_power_state - Set the power state of a PCI device
226  * @dev: PCI device to be suspended
227  * @state: PCI power state (D0, D1, D2, D3hot, D3cold) we're entering
228  *
229  * Transition a device to a new power state, using the Power Management
230  * Capabilities in the device's config space.
231  *
232  * RETURN VALUE:
233  * -EINVAL if trying to enter a lower state than we're already in.
234  * 0 if we're already in the requested state.
235  * -EIO if device does not support PCI PM.
236  * 0 if we can successfully change the power state.
237  */
238 int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t t);
239 int
240 pci_set_power_state(struct pci_dev *dev, pci_power_t state)
241 {
242 	int pm;
243 	u16 pmcsr, pmc;
244 
245 	/* bound the state we're entering */
246 	if (state > PCI_D3hot)
247 		state = PCI_D3hot;
248 
249 	/* Validate current state:
250 	 * Can enter D0 from any state, but if we can only go deeper
251 	 * to sleep if we're already in a low power state
252 	 */
253 	if (state != PCI_D0 && dev->current_state > state)
254 		return -EINVAL;
255 	else if (dev->current_state == state)
256 		return 0;        /* we're already there */
257 
258 	/* find PCI PM capability in list */
259 	pm = pci_find_capability(dev, PCI_CAP_ID_PM);
260 
261 	/* abort if the device doesn't support PM capabilities */
262 	if (!pm)
263 		return -EIO;
264 
265 	pci_read_config_word(dev,pm + PCI_PM_PMC,&pmc);
266 	if ((pmc & PCI_PM_CAP_VER_MASK) > 2) {
267 		printk(KERN_DEBUG
268 		       "PCI: %s has unsupported PM cap regs version (%u)\n",
269 		       pci_name(dev), pmc & PCI_PM_CAP_VER_MASK);
270 		return -EIO;
271 	}
272 
273 	/* check if this device supports the desired state */
274 	if (state == PCI_D1 || state == PCI_D2) {
275 		if (state == PCI_D1 && !(pmc & PCI_PM_CAP_D1))
276 			return -EIO;
277 		else if (state == PCI_D2 && !(pmc & PCI_PM_CAP_D2))
278 			return -EIO;
279 	}
280 
281 	/* If we're in D3, force entire word to 0.
282 	 * This doesn't affect PME_Status, disables PME_En, and
283 	 * sets PowerState to 0.
284 	 */
285 	if (dev->current_state >= PCI_D3hot)
286 		pmcsr = 0;
287 	else {
288 		pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
289 		pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
290 		pmcsr |= state;
291 	}
292 
293 	/* enter specified state */
294 	pci_write_config_word(dev, pm + PCI_PM_CTRL, pmcsr);
295 
296 	/* Mandatory power management transition delays */
297 	/* see PCI PM 1.1 5.6.1 table 18 */
298 	if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
299 		msleep(10);
300 	else if (state == PCI_D2 || dev->current_state == PCI_D2)
301 		udelay(200);
302 
303 	/*
304 	 * Give firmware a chance to be called, such as ACPI _PRx, _PSx
305 	 * Firmware method after natice method ?
306 	 */
307 	if (platform_pci_set_power_state)
308 		platform_pci_set_power_state(dev, state);
309 
310 	dev->current_state = state;
311 	return 0;
312 }
313 
314 int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
315 
316 /**
317  * pci_choose_state - Choose the power state of a PCI device
318  * @dev: PCI device to be suspended
319  * @state: target sleep state for the whole system. This is the value
320  *	that is passed to suspend() function.
321  *
322  * Returns PCI power state suitable for given device and given system
323  * message.
324  */
325 
326 pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state)
327 {
328 	int ret;
329 
330 	if (!pci_find_capability(dev, PCI_CAP_ID_PM))
331 		return PCI_D0;
332 
333 	if (platform_pci_choose_state) {
334 		ret = platform_pci_choose_state(dev, state);
335 		if (ret >= 0)
336 			state = ret;
337 	}
338  	switch (state) {
339 	case 0: return PCI_D0;
340 	case 3: return PCI_D3hot;
341 	default:
342 		printk("They asked me for state %d\n", state);
343 		BUG();
344 	}
345 	return PCI_D0;
346 }
347 
348 EXPORT_SYMBOL(pci_choose_state);
349 
350 /**
351  * pci_save_state - save the PCI configuration space of a device before suspending
352  * @dev: - PCI device that we're dealing with
353  */
354 int
355 pci_save_state(struct pci_dev *dev)
356 {
357 	int i;
358 	/* XXX: 100% dword access ok here? */
359 	for (i = 0; i < 16; i++)
360 		pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]);
361 	return 0;
362 }
363 
364 /**
365  * pci_restore_state - Restore the saved state of a PCI device
366  * @dev: - PCI device that we're dealing with
367  */
368 int
369 pci_restore_state(struct pci_dev *dev)
370 {
371 	int i;
372 
373 	for (i = 0; i < 16; i++)
374 		pci_write_config_dword(dev,i * 4, dev->saved_config_space[i]);
375 	return 0;
376 }
377 
378 /**
379  * pci_enable_device_bars - Initialize some of a device for use
380  * @dev: PCI device to be initialized
381  * @bars: bitmask of BAR's that must be configured
382  *
383  *  Initialize device before it's used by a driver. Ask low-level code
384  *  to enable selected I/O and memory resources. Wake up the device if it
385  *  was suspended. Beware, this function can fail.
386  */
387 
388 int
389 pci_enable_device_bars(struct pci_dev *dev, int bars)
390 {
391 	int err;
392 
393 	pci_set_power_state(dev, PCI_D0);
394 	if ((err = pcibios_enable_device(dev, bars)) < 0)
395 		return err;
396 	return 0;
397 }
398 
399 /**
400  * pci_enable_device - Initialize device before it's used by a driver.
401  * @dev: PCI device to be initialized
402  *
403  *  Initialize device before it's used by a driver. Ask low-level code
404  *  to enable I/O and memory. Wake up the device if it was suspended.
405  *  Beware, this function can fail.
406  */
407 int
408 pci_enable_device(struct pci_dev *dev)
409 {
410 	int err;
411 
412 	if ((err = pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1)))
413 		return err;
414 	pci_fixup_device(pci_fixup_enable, dev);
415 	dev->is_enabled = 1;
416 	return 0;
417 }
418 
419 /**
420  * pcibios_disable_device - disable arch specific PCI resources for device dev
421  * @dev: the PCI device to disable
422  *
423  * Disables architecture specific PCI resources for the device. This
424  * is the default implementation. Architecture implementations can
425  * override this.
426  */
427 void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {}
428 
429 /**
430  * pci_disable_device - Disable PCI device after use
431  * @dev: PCI device to be disabled
432  *
433  * Signal to the system that the PCI device is not in use by the system
434  * anymore.  This only involves disabling PCI bus-mastering, if active.
435  */
436 void
437 pci_disable_device(struct pci_dev *dev)
438 {
439 	u16 pci_command;
440 
441 	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
442 	if (pci_command & PCI_COMMAND_MASTER) {
443 		pci_command &= ~PCI_COMMAND_MASTER;
444 		pci_write_config_word(dev, PCI_COMMAND, pci_command);
445 	}
446 	dev->is_busmaster = 0;
447 
448 	pcibios_disable_device(dev);
449 	dev->is_enabled = 0;
450 }
451 
452 /**
453  * pci_enable_wake - enable device to generate PME# when suspended
454  * @dev: - PCI device to operate on
455  * @state: - Current state of device.
456  * @enable: - Flag to enable or disable generation
457  *
458  * Set the bits in the device's PM Capabilities to generate PME# when
459  * the system is suspended.
460  *
461  * -EIO is returned if device doesn't have PM Capabilities.
462  * -EINVAL is returned if device supports it, but can't generate wake events.
463  * 0 if operation is successful.
464  *
465  */
466 int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
467 {
468 	int pm;
469 	u16 value;
470 
471 	/* find PCI PM capability in list */
472 	pm = pci_find_capability(dev, PCI_CAP_ID_PM);
473 
474 	/* If device doesn't support PM Capabilities, but request is to disable
475 	 * wake events, it's a nop; otherwise fail */
476 	if (!pm)
477 		return enable ? -EIO : 0;
478 
479 	/* Check device's ability to generate PME# */
480 	pci_read_config_word(dev,pm+PCI_PM_PMC,&value);
481 
482 	value &= PCI_PM_CAP_PME_MASK;
483 	value >>= ffs(PCI_PM_CAP_PME_MASK) - 1;   /* First bit of mask */
484 
485 	/* Check if it can generate PME# from requested state. */
486 	if (!value || !(value & (1 << state)))
487 		return enable ? -EINVAL : 0;
488 
489 	pci_read_config_word(dev, pm + PCI_PM_CTRL, &value);
490 
491 	/* Clear PME_Status by writing 1 to it and enable PME# */
492 	value |= PCI_PM_CTRL_PME_STATUS | PCI_PM_CTRL_PME_ENABLE;
493 
494 	if (!enable)
495 		value &= ~PCI_PM_CTRL_PME_ENABLE;
496 
497 	pci_write_config_word(dev, pm + PCI_PM_CTRL, value);
498 
499 	return 0;
500 }
501 
502 int
503 pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
504 {
505 	u8 pin;
506 
507 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
508 	if (!pin)
509 		return -1;
510 	pin--;
511 	while (dev->bus->self) {
512 		pin = (pin + PCI_SLOT(dev->devfn)) % 4;
513 		dev = dev->bus->self;
514 	}
515 	*bridge = dev;
516 	return pin;
517 }
518 
519 /**
520  *	pci_release_region - Release a PCI bar
521  *	@pdev: PCI device whose resources were previously reserved by pci_request_region
522  *	@bar: BAR to release
523  *
524  *	Releases the PCI I/O and memory resources previously reserved by a
525  *	successful call to pci_request_region.  Call this function only
526  *	after all use of the PCI regions has ceased.
527  */
528 void pci_release_region(struct pci_dev *pdev, int bar)
529 {
530 	if (pci_resource_len(pdev, bar) == 0)
531 		return;
532 	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
533 		release_region(pci_resource_start(pdev, bar),
534 				pci_resource_len(pdev, bar));
535 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
536 		release_mem_region(pci_resource_start(pdev, bar),
537 				pci_resource_len(pdev, bar));
538 }
539 
540 /**
541  *	pci_request_region - Reserved PCI I/O and memory resource
542  *	@pdev: PCI device whose resources are to be reserved
543  *	@bar: BAR to be reserved
544  *	@res_name: Name to be associated with resource.
545  *
546  *	Mark the PCI region associated with PCI device @pdev BR @bar as
547  *	being reserved by owner @res_name.  Do not access any
548  *	address inside the PCI regions unless this call returns
549  *	successfully.
550  *
551  *	Returns 0 on success, or %EBUSY on error.  A warning
552  *	message is also printed on failure.
553  */
554 int pci_request_region(struct pci_dev *pdev, int bar, char *res_name)
555 {
556 	if (pci_resource_len(pdev, bar) == 0)
557 		return 0;
558 
559 	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO) {
560 		if (!request_region(pci_resource_start(pdev, bar),
561 			    pci_resource_len(pdev, bar), res_name))
562 			goto err_out;
563 	}
564 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM) {
565 		if (!request_mem_region(pci_resource_start(pdev, bar),
566 				        pci_resource_len(pdev, bar), res_name))
567 			goto err_out;
568 	}
569 
570 	return 0;
571 
572 err_out:
573 	printk (KERN_WARNING "PCI: Unable to reserve %s region #%d:%lx@%lx for device %s\n",
574 		pci_resource_flags(pdev, bar) & IORESOURCE_IO ? "I/O" : "mem",
575 		bar + 1, /* PCI BAR # */
576 		pci_resource_len(pdev, bar), pci_resource_start(pdev, bar),
577 		pci_name(pdev));
578 	return -EBUSY;
579 }
580 
581 
582 /**
583  *	pci_release_regions - Release reserved PCI I/O and memory resources
584  *	@pdev: PCI device whose resources were previously reserved by pci_request_regions
585  *
586  *	Releases all PCI I/O and memory resources previously reserved by a
587  *	successful call to pci_request_regions.  Call this function only
588  *	after all use of the PCI regions has ceased.
589  */
590 
591 void pci_release_regions(struct pci_dev *pdev)
592 {
593 	int i;
594 
595 	for (i = 0; i < 6; i++)
596 		pci_release_region(pdev, i);
597 }
598 
599 /**
600  *	pci_request_regions - Reserved PCI I/O and memory resources
601  *	@pdev: PCI device whose resources are to be reserved
602  *	@res_name: Name to be associated with resource.
603  *
604  *	Mark all PCI regions associated with PCI device @pdev as
605  *	being reserved by owner @res_name.  Do not access any
606  *	address inside the PCI regions unless this call returns
607  *	successfully.
608  *
609  *	Returns 0 on success, or %EBUSY on error.  A warning
610  *	message is also printed on failure.
611  */
612 int pci_request_regions(struct pci_dev *pdev, char *res_name)
613 {
614 	int i;
615 
616 	for (i = 0; i < 6; i++)
617 		if(pci_request_region(pdev, i, res_name))
618 			goto err_out;
619 	return 0;
620 
621 err_out:
622 	while(--i >= 0)
623 		pci_release_region(pdev, i);
624 
625 	return -EBUSY;
626 }
627 
628 /**
629  * pci_set_master - enables bus-mastering for device dev
630  * @dev: the PCI device to enable
631  *
632  * Enables bus-mastering on the device and calls pcibios_set_master()
633  * to do the needed arch specific settings.
634  */
635 void
636 pci_set_master(struct pci_dev *dev)
637 {
638 	u16 cmd;
639 
640 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
641 	if (! (cmd & PCI_COMMAND_MASTER)) {
642 		pr_debug("PCI: Enabling bus mastering for device %s\n", pci_name(dev));
643 		cmd |= PCI_COMMAND_MASTER;
644 		pci_write_config_word(dev, PCI_COMMAND, cmd);
645 	}
646 	dev->is_busmaster = 1;
647 	pcibios_set_master(dev);
648 }
649 
650 #ifndef HAVE_ARCH_PCI_MWI
651 /* This can be overridden by arch code. */
652 u8 pci_cache_line_size = L1_CACHE_BYTES >> 2;
653 
654 /**
655  * pci_generic_prep_mwi - helper function for pci_set_mwi
656  * @dev: the PCI device for which MWI is enabled
657  *
658  * Helper function for generic implementation of pcibios_prep_mwi
659  * function.  Originally copied from drivers/net/acenic.c.
660  * Copyright 1998-2001 by Jes Sorensen, <jes@trained-monkey.org>.
661  *
662  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
663  */
664 static int
665 pci_generic_prep_mwi(struct pci_dev *dev)
666 {
667 	u8 cacheline_size;
668 
669 	if (!pci_cache_line_size)
670 		return -EINVAL;		/* The system doesn't support MWI. */
671 
672 	/* Validate current setting: the PCI_CACHE_LINE_SIZE must be
673 	   equal to or multiple of the right value. */
674 	pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
675 	if (cacheline_size >= pci_cache_line_size &&
676 	    (cacheline_size % pci_cache_line_size) == 0)
677 		return 0;
678 
679 	/* Write the correct value. */
680 	pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, pci_cache_line_size);
681 	/* Read it back. */
682 	pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
683 	if (cacheline_size == pci_cache_line_size)
684 		return 0;
685 
686 	printk(KERN_DEBUG "PCI: cache line size of %d is not supported "
687 	       "by device %s\n", pci_cache_line_size << 2, pci_name(dev));
688 
689 	return -EINVAL;
690 }
691 #endif /* !HAVE_ARCH_PCI_MWI */
692 
693 /**
694  * pci_set_mwi - enables memory-write-invalidate PCI transaction
695  * @dev: the PCI device for which MWI is enabled
696  *
697  * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND,
698  * and then calls @pcibios_set_mwi to do the needed arch specific
699  * operations or a generic mwi-prep function.
700  *
701  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
702  */
703 int
704 pci_set_mwi(struct pci_dev *dev)
705 {
706 	int rc;
707 	u16 cmd;
708 
709 #ifdef HAVE_ARCH_PCI_MWI
710 	rc = pcibios_prep_mwi(dev);
711 #else
712 	rc = pci_generic_prep_mwi(dev);
713 #endif
714 
715 	if (rc)
716 		return rc;
717 
718 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
719 	if (! (cmd & PCI_COMMAND_INVALIDATE)) {
720 		pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
721 		cmd |= PCI_COMMAND_INVALIDATE;
722 		pci_write_config_word(dev, PCI_COMMAND, cmd);
723 	}
724 
725 	return 0;
726 }
727 
728 /**
729  * pci_clear_mwi - disables Memory-Write-Invalidate for device dev
730  * @dev: the PCI device to disable
731  *
732  * Disables PCI Memory-Write-Invalidate transaction on the device
733  */
734 void
735 pci_clear_mwi(struct pci_dev *dev)
736 {
737 	u16 cmd;
738 
739 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
740 	if (cmd & PCI_COMMAND_INVALIDATE) {
741 		cmd &= ~PCI_COMMAND_INVALIDATE;
742 		pci_write_config_word(dev, PCI_COMMAND, cmd);
743 	}
744 }
745 
746 #ifndef HAVE_ARCH_PCI_SET_DMA_MASK
747 /*
748  * These can be overridden by arch-specific implementations
749  */
750 int
751 pci_set_dma_mask(struct pci_dev *dev, u64 mask)
752 {
753 	if (!pci_dma_supported(dev, mask))
754 		return -EIO;
755 
756 	dev->dma_mask = mask;
757 
758 	return 0;
759 }
760 
761 int
762 pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
763 {
764 	if (!pci_dma_supported(dev, mask))
765 		return -EIO;
766 
767 	dev->dev.coherent_dma_mask = mask;
768 
769 	return 0;
770 }
771 #endif
772 
773 static int __devinit pci_init(void)
774 {
775 	struct pci_dev *dev = NULL;
776 
777 	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
778 		pci_fixup_device(pci_fixup_final, dev);
779 	}
780 	return 0;
781 }
782 
783 static int __devinit pci_setup(char *str)
784 {
785 	while (str) {
786 		char *k = strchr(str, ',');
787 		if (k)
788 			*k++ = 0;
789 		if (*str && (str = pcibios_setup(str)) && *str) {
790 			/* PCI layer options should be handled here */
791 			printk(KERN_ERR "PCI: Unknown option `%s'\n", str);
792 		}
793 		str = k;
794 	}
795 	return 1;
796 }
797 
798 device_initcall(pci_init);
799 
800 __setup("pci=", pci_setup);
801 
802 #if defined(CONFIG_ISA) || defined(CONFIG_EISA)
803 /* FIXME: Some boxes have multiple ISA bridges! */
804 struct pci_dev *isa_bridge;
805 EXPORT_SYMBOL(isa_bridge);
806 #endif
807 
808 EXPORT_SYMBOL(pci_enable_device_bars);
809 EXPORT_SYMBOL(pci_enable_device);
810 EXPORT_SYMBOL(pci_disable_device);
811 EXPORT_SYMBOL(pci_max_busnr);
812 EXPORT_SYMBOL(pci_bus_max_busnr);
813 EXPORT_SYMBOL(pci_find_capability);
814 EXPORT_SYMBOL(pci_bus_find_capability);
815 EXPORT_SYMBOL(pci_release_regions);
816 EXPORT_SYMBOL(pci_request_regions);
817 EXPORT_SYMBOL(pci_release_region);
818 EXPORT_SYMBOL(pci_request_region);
819 EXPORT_SYMBOL(pci_set_master);
820 EXPORT_SYMBOL(pci_set_mwi);
821 EXPORT_SYMBOL(pci_clear_mwi);
822 EXPORT_SYMBOL(pci_set_dma_mask);
823 EXPORT_SYMBOL(pci_set_consistent_dma_mask);
824 EXPORT_SYMBOL(pci_assign_resource);
825 EXPORT_SYMBOL(pci_find_parent_resource);
826 
827 EXPORT_SYMBOL(pci_set_power_state);
828 EXPORT_SYMBOL(pci_save_state);
829 EXPORT_SYMBOL(pci_restore_state);
830 EXPORT_SYMBOL(pci_enable_wake);
831 
832 /* Quirk info */
833 
834 EXPORT_SYMBOL(isa_dma_bridge_buggy);
835 EXPORT_SYMBOL(pci_pci_problems);
836