xref: /linux/drivers/pci/pci.c (revision 6e8331ac6973435b1e7604c30f2ad394035b46e1)
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 <linux/string.h>
19 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
20 #include "pci.h"
21 
22 unsigned int pci_pm_d3_delay = 10;
23 
24 /**
25  * pci_bus_max_busnr - returns maximum PCI bus number of given bus' children
26  * @bus: pointer to PCI bus structure to search
27  *
28  * Given a PCI bus, returns the highest PCI bus number present in the set
29  * including the given PCI bus and its list of child PCI buses.
30  */
31 unsigned char __devinit
32 pci_bus_max_busnr(struct pci_bus* bus)
33 {
34 	struct list_head *tmp;
35 	unsigned char max, n;
36 
37 	max = bus->subordinate;
38 	list_for_each(tmp, &bus->children) {
39 		n = pci_bus_max_busnr(pci_bus_b(tmp));
40 		if(n > max)
41 			max = n;
42 	}
43 	return max;
44 }
45 EXPORT_SYMBOL_GPL(pci_bus_max_busnr);
46 
47 #if 0
48 /**
49  * pci_max_busnr - returns maximum PCI bus number
50  *
51  * Returns the highest PCI bus number present in the system global list of
52  * PCI buses.
53  */
54 unsigned char __devinit
55 pci_max_busnr(void)
56 {
57 	struct pci_bus *bus = NULL;
58 	unsigned char max, n;
59 
60 	max = 0;
61 	while ((bus = pci_find_next_bus(bus)) != NULL) {
62 		n = pci_bus_max_busnr(bus);
63 		if(n > max)
64 			max = n;
65 	}
66 	return max;
67 }
68 
69 #endif  /*  0  */
70 
71 static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap)
72 {
73 	u8 id;
74 	int ttl = 48;
75 
76 	while (ttl--) {
77 		pci_bus_read_config_byte(bus, devfn, pos, &pos);
78 		if (pos < 0x40)
79 			break;
80 		pos &= ~3;
81 		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID,
82 					 &id);
83 		if (id == 0xff)
84 			break;
85 		if (id == cap)
86 			return pos;
87 		pos += PCI_CAP_LIST_NEXT;
88 	}
89 	return 0;
90 }
91 
92 int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
93 {
94 	return __pci_find_next_cap(dev->bus, dev->devfn,
95 				   pos + PCI_CAP_LIST_NEXT, cap);
96 }
97 EXPORT_SYMBOL_GPL(pci_find_next_capability);
98 
99 static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_type, int cap)
100 {
101 	u16 status;
102 	u8 pos;
103 
104 	pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
105 	if (!(status & PCI_STATUS_CAP_LIST))
106 		return 0;
107 
108 	switch (hdr_type) {
109 	case PCI_HEADER_TYPE_NORMAL:
110 	case PCI_HEADER_TYPE_BRIDGE:
111 		pos = PCI_CAPABILITY_LIST;
112 		break;
113 	case PCI_HEADER_TYPE_CARDBUS:
114 		pos = PCI_CB_CAPABILITY_LIST;
115 		break;
116 	default:
117 		return 0;
118 	}
119 	return __pci_find_next_cap(bus, devfn, pos, cap);
120 }
121 
122 /**
123  * pci_find_capability - query for devices' capabilities
124  * @dev: PCI device to query
125  * @cap: capability code
126  *
127  * Tell if a device supports a given PCI capability.
128  * Returns the address of the requested capability structure within the
129  * device's PCI configuration space or 0 in case the device does not
130  * support it.  Possible values for @cap:
131  *
132  *  %PCI_CAP_ID_PM           Power Management
133  *  %PCI_CAP_ID_AGP          Accelerated Graphics Port
134  *  %PCI_CAP_ID_VPD          Vital Product Data
135  *  %PCI_CAP_ID_SLOTID       Slot Identification
136  *  %PCI_CAP_ID_MSI          Message Signalled Interrupts
137  *  %PCI_CAP_ID_CHSWP        CompactPCI HotSwap
138  *  %PCI_CAP_ID_PCIX         PCI-X
139  *  %PCI_CAP_ID_EXP          PCI Express
140  */
141 int pci_find_capability(struct pci_dev *dev, int cap)
142 {
143 	return __pci_bus_find_cap(dev->bus, dev->devfn, dev->hdr_type, cap);
144 }
145 
146 /**
147  * pci_bus_find_capability - query for devices' capabilities
148  * @bus:   the PCI bus to query
149  * @devfn: PCI device to query
150  * @cap:   capability code
151  *
152  * Like pci_find_capability() but works for pci devices that do not have a
153  * pci_dev structure set up yet.
154  *
155  * Returns the address of the requested capability structure within the
156  * device's PCI configuration space or 0 in case the device does not
157  * support it.
158  */
159 int pci_bus_find_capability(struct pci_bus *bus, unsigned int devfn, int cap)
160 {
161 	u8 hdr_type;
162 
163 	pci_bus_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type);
164 
165 	return __pci_bus_find_cap(bus, devfn, hdr_type & 0x7f, cap);
166 }
167 
168 /**
169  * pci_find_ext_capability - Find an extended capability
170  * @dev: PCI device to query
171  * @cap: capability code
172  *
173  * Returns the address of the requested extended capability structure
174  * within the device's PCI configuration space or 0 if the device does
175  * not support it.  Possible values for @cap:
176  *
177  *  %PCI_EXT_CAP_ID_ERR		Advanced Error Reporting
178  *  %PCI_EXT_CAP_ID_VC		Virtual Channel
179  *  %PCI_EXT_CAP_ID_DSN		Device Serial Number
180  *  %PCI_EXT_CAP_ID_PWR		Power Budgeting
181  */
182 int pci_find_ext_capability(struct pci_dev *dev, int cap)
183 {
184 	u32 header;
185 	int ttl = 480; /* 3840 bytes, minimum 8 bytes per capability */
186 	int pos = 0x100;
187 
188 	if (dev->cfg_size <= 256)
189 		return 0;
190 
191 	if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
192 		return 0;
193 
194 	/*
195 	 * If we have no capabilities, this is indicated by cap ID,
196 	 * cap version and next pointer all being 0.
197 	 */
198 	if (header == 0)
199 		return 0;
200 
201 	while (ttl-- > 0) {
202 		if (PCI_EXT_CAP_ID(header) == cap)
203 			return pos;
204 
205 		pos = PCI_EXT_CAP_NEXT(header);
206 		if (pos < 0x100)
207 			break;
208 
209 		if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)
210 			break;
211 	}
212 
213 	return 0;
214 }
215 EXPORT_SYMBOL_GPL(pci_find_ext_capability);
216 
217 /**
218  * pci_find_parent_resource - return resource region of parent bus of given region
219  * @dev: PCI device structure contains resources to be searched
220  * @res: child resource record for which parent is sought
221  *
222  *  For given resource region of given device, return the resource
223  *  region of parent bus the given region is contained in or where
224  *  it should be allocated from.
225  */
226 struct resource *
227 pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
228 {
229 	const struct pci_bus *bus = dev->bus;
230 	int i;
231 	struct resource *best = NULL;
232 
233 	for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
234 		struct resource *r = bus->resource[i];
235 		if (!r)
236 			continue;
237 		if (res->start && !(res->start >= r->start && res->end <= r->end))
238 			continue;	/* Not contained */
239 		if ((res->flags ^ r->flags) & (IORESOURCE_IO | IORESOURCE_MEM))
240 			continue;	/* Wrong type */
241 		if (!((res->flags ^ r->flags) & IORESOURCE_PREFETCH))
242 			return r;	/* Exact match */
243 		if ((res->flags & IORESOURCE_PREFETCH) && !(r->flags & IORESOURCE_PREFETCH))
244 			best = r;	/* Approximating prefetchable by non-prefetchable */
245 	}
246 	return best;
247 }
248 
249 /**
250  * pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
251  * @dev: PCI device to have its BARs restored
252  *
253  * Restore the BAR values for a given device, so as to make it
254  * accessible by its driver.
255  */
256 void
257 pci_restore_bars(struct pci_dev *dev)
258 {
259 	int i, numres;
260 
261 	switch (dev->hdr_type) {
262 	case PCI_HEADER_TYPE_NORMAL:
263 		numres = 6;
264 		break;
265 	case PCI_HEADER_TYPE_BRIDGE:
266 		numres = 2;
267 		break;
268 	case PCI_HEADER_TYPE_CARDBUS:
269 		numres = 1;
270 		break;
271 	default:
272 		/* Should never get here, but just in case... */
273 		return;
274 	}
275 
276 	for (i = 0; i < numres; i ++)
277 		pci_update_resource(dev, &dev->resource[i], i);
278 }
279 
280 int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t t);
281 
282 /**
283  * pci_set_power_state - Set the power state of a PCI device
284  * @dev: PCI device to be suspended
285  * @state: PCI power state (D0, D1, D2, D3hot, D3cold) we're entering
286  *
287  * Transition a device to a new power state, using the Power Management
288  * Capabilities in the device's config space.
289  *
290  * RETURN VALUE:
291  * -EINVAL if trying to enter a lower state than we're already in.
292  * 0 if we're already in the requested state.
293  * -EIO if device does not support PCI PM.
294  * 0 if we can successfully change the power state.
295  */
296 int
297 pci_set_power_state(struct pci_dev *dev, pci_power_t state)
298 {
299 	int pm, need_restore = 0;
300 	u16 pmcsr, pmc;
301 
302 	/* bound the state we're entering */
303 	if (state > PCI_D3hot)
304 		state = PCI_D3hot;
305 
306 	/* Validate current state:
307 	 * Can enter D0 from any state, but if we can only go deeper
308 	 * to sleep if we're already in a low power state
309 	 */
310 	if (state != PCI_D0 && dev->current_state > state) {
311 		printk(KERN_ERR "%s(): %s: state=%d, current state=%d\n",
312 			__FUNCTION__, pci_name(dev), state, dev->current_state);
313 		return -EINVAL;
314 	} else if (dev->current_state == state)
315 		return 0;        /* we're already there */
316 
317 	/*
318 	 * If the device or the parent bridge can't support PCI PM, ignore
319 	 * the request if we're doing anything besides putting it into D0
320 	 * (which would only happen on boot).
321 	 */
322 	if ((state == PCI_D1 || state == PCI_D2) && pci_no_d1d2(dev))
323 		return 0;
324 
325 	/* find PCI PM capability in list */
326 	pm = pci_find_capability(dev, PCI_CAP_ID_PM);
327 
328 	/* abort if the device doesn't support PM capabilities */
329 	if (!pm)
330 		return -EIO;
331 
332 	pci_read_config_word(dev,pm + PCI_PM_PMC,&pmc);
333 	if ((pmc & PCI_PM_CAP_VER_MASK) > 3) {
334 		printk(KERN_DEBUG
335 		       "PCI: %s has unsupported PM cap regs version (%u)\n",
336 		       pci_name(dev), pmc & PCI_PM_CAP_VER_MASK);
337 		return -EIO;
338 	}
339 
340 	/* check if this device supports the desired state */
341 	if (state == PCI_D1 && !(pmc & PCI_PM_CAP_D1))
342 		return -EIO;
343 	else if (state == PCI_D2 && !(pmc & PCI_PM_CAP_D2))
344 		return -EIO;
345 
346 	pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
347 
348 	/* If we're (effectively) in D3, force entire word to 0.
349 	 * This doesn't affect PME_Status, disables PME_En, and
350 	 * sets PowerState to 0.
351 	 */
352 	switch (dev->current_state) {
353 	case PCI_D0:
354 	case PCI_D1:
355 	case PCI_D2:
356 		pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
357 		pmcsr |= state;
358 		break;
359 	case PCI_UNKNOWN: /* Boot-up */
360 		if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
361 		 && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
362 			need_restore = 1;
363 		/* Fall-through: force to D0 */
364 	default:
365 		pmcsr = 0;
366 		break;
367 	}
368 
369 	/* enter specified state */
370 	pci_write_config_word(dev, pm + PCI_PM_CTRL, pmcsr);
371 
372 	/* Mandatory power management transition delays */
373 	/* see PCI PM 1.1 5.6.1 table 18 */
374 	if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
375 		msleep(pci_pm_d3_delay);
376 	else if (state == PCI_D2 || dev->current_state == PCI_D2)
377 		udelay(200);
378 
379 	/*
380 	 * Give firmware a chance to be called, such as ACPI _PRx, _PSx
381 	 * Firmware method after native method ?
382 	 */
383 	if (platform_pci_set_power_state)
384 		platform_pci_set_power_state(dev, state);
385 
386 	dev->current_state = state;
387 
388 	/* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
389 	 * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
390 	 * from D3hot to D0 _may_ perform an internal reset, thereby
391 	 * going to "D0 Uninitialized" rather than "D0 Initialized".
392 	 * For example, at least some versions of the 3c905B and the
393 	 * 3c556B exhibit this behaviour.
394 	 *
395 	 * At least some laptop BIOSen (e.g. the Thinkpad T21) leave
396 	 * devices in a D3hot state at boot.  Consequently, we need to
397 	 * restore at least the BARs so that the device will be
398 	 * accessible to its driver.
399 	 */
400 	if (need_restore)
401 		pci_restore_bars(dev);
402 
403 	return 0;
404 }
405 
406 int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
407 
408 /**
409  * pci_choose_state - Choose the power state of a PCI device
410  * @dev: PCI device to be suspended
411  * @state: target sleep state for the whole system. This is the value
412  *	that is passed to suspend() function.
413  *
414  * Returns PCI power state suitable for given device and given system
415  * message.
416  */
417 
418 pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state)
419 {
420 	int ret;
421 
422 	if (!pci_find_capability(dev, PCI_CAP_ID_PM))
423 		return PCI_D0;
424 
425 	if (platform_pci_choose_state) {
426 		ret = platform_pci_choose_state(dev, state);
427 		if (ret >= 0)
428 			state.event = ret;
429 	}
430 
431 	switch (state.event) {
432 	case PM_EVENT_ON:
433 		return PCI_D0;
434 	case PM_EVENT_FREEZE:
435 	case PM_EVENT_SUSPEND:
436 		return PCI_D3hot;
437 	default:
438 		printk("They asked me for state %d\n", state.event);
439 		BUG();
440 	}
441 	return PCI_D0;
442 }
443 
444 EXPORT_SYMBOL(pci_choose_state);
445 
446 /**
447  * pci_save_state - save the PCI configuration space of a device before suspending
448  * @dev: - PCI device that we're dealing with
449  */
450 int
451 pci_save_state(struct pci_dev *dev)
452 {
453 	int i;
454 	/* XXX: 100% dword access ok here? */
455 	for (i = 0; i < 16; i++)
456 		pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]);
457 	if ((i = pci_save_msi_state(dev)) != 0)
458 		return i;
459 	if ((i = pci_save_msix_state(dev)) != 0)
460 		return i;
461 	return 0;
462 }
463 
464 /**
465  * pci_restore_state - Restore the saved state of a PCI device
466  * @dev: - PCI device that we're dealing with
467  */
468 int
469 pci_restore_state(struct pci_dev *dev)
470 {
471 	int i;
472 	int val;
473 
474 	/*
475 	 * The Base Address register should be programmed before the command
476 	 * register(s)
477 	 */
478 	for (i = 15; i >= 0; i--) {
479 		pci_read_config_dword(dev, i * 4, &val);
480 		if (val != dev->saved_config_space[i]) {
481 			printk(KERN_DEBUG "PM: Writing back config space on "
482 				"device %s at offset %x (was %x, writing %x)\n",
483 				pci_name(dev), i,
484 				val, (int)dev->saved_config_space[i]);
485 			pci_write_config_dword(dev,i * 4,
486 				dev->saved_config_space[i]);
487 		}
488 	}
489 	pci_restore_msi_state(dev);
490 	pci_restore_msix_state(dev);
491 	return 0;
492 }
493 
494 /**
495  * pci_enable_device_bars - Initialize some of a device for use
496  * @dev: PCI device to be initialized
497  * @bars: bitmask of BAR's that must be configured
498  *
499  *  Initialize device before it's used by a driver. Ask low-level code
500  *  to enable selected I/O and memory resources. Wake up the device if it
501  *  was suspended. Beware, this function can fail.
502  */
503 
504 int
505 pci_enable_device_bars(struct pci_dev *dev, int bars)
506 {
507 	int err;
508 
509 	err = pci_set_power_state(dev, PCI_D0);
510 	if (err < 0 && err != -EIO)
511 		return err;
512 	err = pcibios_enable_device(dev, bars);
513 	if (err < 0)
514 		return err;
515 	return 0;
516 }
517 
518 /**
519  * pci_enable_device - Initialize device before it's used by a driver.
520  * @dev: PCI device to be initialized
521  *
522  *  Initialize device before it's used by a driver. Ask low-level code
523  *  to enable I/O and memory. Wake up the device if it was suspended.
524  *  Beware, this function can fail.
525  */
526 int
527 pci_enable_device(struct pci_dev *dev)
528 {
529 	int err;
530 
531 	if (dev->is_enabled)
532 		return 0;
533 
534 	err = pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1);
535 	if (err)
536 		return err;
537 	pci_fixup_device(pci_fixup_enable, dev);
538 	dev->is_enabled = 1;
539 	return 0;
540 }
541 
542 /**
543  * pcibios_disable_device - disable arch specific PCI resources for device dev
544  * @dev: the PCI device to disable
545  *
546  * Disables architecture specific PCI resources for the device. This
547  * is the default implementation. Architecture implementations can
548  * override this.
549  */
550 void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {}
551 
552 /**
553  * pci_disable_device - Disable PCI device after use
554  * @dev: PCI device to be disabled
555  *
556  * Signal to the system that the PCI device is not in use by the system
557  * anymore.  This only involves disabling PCI bus-mastering, if active.
558  */
559 void
560 pci_disable_device(struct pci_dev *dev)
561 {
562 	u16 pci_command;
563 
564 	if (dev->msi_enabled)
565 		disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
566 			PCI_CAP_ID_MSI);
567 	if (dev->msix_enabled)
568 		disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
569 			PCI_CAP_ID_MSIX);
570 
571 	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
572 	if (pci_command & PCI_COMMAND_MASTER) {
573 		pci_command &= ~PCI_COMMAND_MASTER;
574 		pci_write_config_word(dev, PCI_COMMAND, pci_command);
575 	}
576 	dev->is_busmaster = 0;
577 
578 	pcibios_disable_device(dev);
579 	dev->is_enabled = 0;
580 }
581 
582 /**
583  * pci_enable_wake - enable device to generate PME# when suspended
584  * @dev: - PCI device to operate on
585  * @state: - Current state of device.
586  * @enable: - Flag to enable or disable generation
587  *
588  * Set the bits in the device's PM Capabilities to generate PME# when
589  * the system is suspended.
590  *
591  * -EIO is returned if device doesn't have PM Capabilities.
592  * -EINVAL is returned if device supports it, but can't generate wake events.
593  * 0 if operation is successful.
594  *
595  */
596 int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
597 {
598 	int pm;
599 	u16 value;
600 
601 	/* find PCI PM capability in list */
602 	pm = pci_find_capability(dev, PCI_CAP_ID_PM);
603 
604 	/* If device doesn't support PM Capabilities, but request is to disable
605 	 * wake events, it's a nop; otherwise fail */
606 	if (!pm)
607 		return enable ? -EIO : 0;
608 
609 	/* Check device's ability to generate PME# */
610 	pci_read_config_word(dev,pm+PCI_PM_PMC,&value);
611 
612 	value &= PCI_PM_CAP_PME_MASK;
613 	value >>= ffs(PCI_PM_CAP_PME_MASK) - 1;   /* First bit of mask */
614 
615 	/* Check if it can generate PME# from requested state. */
616 	if (!value || !(value & (1 << state)))
617 		return enable ? -EINVAL : 0;
618 
619 	pci_read_config_word(dev, pm + PCI_PM_CTRL, &value);
620 
621 	/* Clear PME_Status by writing 1 to it and enable PME# */
622 	value |= PCI_PM_CTRL_PME_STATUS | PCI_PM_CTRL_PME_ENABLE;
623 
624 	if (!enable)
625 		value &= ~PCI_PM_CTRL_PME_ENABLE;
626 
627 	pci_write_config_word(dev, pm + PCI_PM_CTRL, value);
628 
629 	return 0;
630 }
631 
632 int
633 pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
634 {
635 	u8 pin;
636 
637 	pin = dev->pin;
638 	if (!pin)
639 		return -1;
640 	pin--;
641 	while (dev->bus->self) {
642 		pin = (pin + PCI_SLOT(dev->devfn)) % 4;
643 		dev = dev->bus->self;
644 	}
645 	*bridge = dev;
646 	return pin;
647 }
648 
649 /**
650  *	pci_release_region - Release a PCI bar
651  *	@pdev: PCI device whose resources were previously reserved by pci_request_region
652  *	@bar: BAR to release
653  *
654  *	Releases the PCI I/O and memory resources previously reserved by a
655  *	successful call to pci_request_region.  Call this function only
656  *	after all use of the PCI regions has ceased.
657  */
658 void pci_release_region(struct pci_dev *pdev, int bar)
659 {
660 	if (pci_resource_len(pdev, bar) == 0)
661 		return;
662 	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
663 		release_region(pci_resource_start(pdev, bar),
664 				pci_resource_len(pdev, bar));
665 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
666 		release_mem_region(pci_resource_start(pdev, bar),
667 				pci_resource_len(pdev, bar));
668 }
669 
670 /**
671  *	pci_request_region - Reserved PCI I/O and memory resource
672  *	@pdev: PCI device whose resources are to be reserved
673  *	@bar: BAR to be reserved
674  *	@res_name: Name to be associated with resource.
675  *
676  *	Mark the PCI region associated with PCI device @pdev BR @bar as
677  *	being reserved by owner @res_name.  Do not access any
678  *	address inside the PCI regions unless this call returns
679  *	successfully.
680  *
681  *	Returns 0 on success, or %EBUSY on error.  A warning
682  *	message is also printed on failure.
683  */
684 int pci_request_region(struct pci_dev *pdev, int bar, const char *res_name)
685 {
686 	if (pci_resource_len(pdev, bar) == 0)
687 		return 0;
688 
689 	if (pci_resource_flags(pdev, bar) & IORESOURCE_IO) {
690 		if (!request_region(pci_resource_start(pdev, bar),
691 			    pci_resource_len(pdev, bar), res_name))
692 			goto err_out;
693 	}
694 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM) {
695 		if (!request_mem_region(pci_resource_start(pdev, bar),
696 				        pci_resource_len(pdev, bar), res_name))
697 			goto err_out;
698 	}
699 
700 	return 0;
701 
702 err_out:
703 	printk (KERN_WARNING "PCI: Unable to reserve %s region #%d:%llx@%llx "
704 		"for device %s\n",
705 		pci_resource_flags(pdev, bar) & IORESOURCE_IO ? "I/O" : "mem",
706 		bar + 1, /* PCI BAR # */
707 		(unsigned long long)pci_resource_len(pdev, bar),
708 		(unsigned long long)pci_resource_start(pdev, bar),
709 		pci_name(pdev));
710 	return -EBUSY;
711 }
712 
713 
714 /**
715  *	pci_release_regions - Release reserved PCI I/O and memory resources
716  *	@pdev: PCI device whose resources were previously reserved by pci_request_regions
717  *
718  *	Releases all PCI I/O and memory resources previously reserved by a
719  *	successful call to pci_request_regions.  Call this function only
720  *	after all use of the PCI regions has ceased.
721  */
722 
723 void pci_release_regions(struct pci_dev *pdev)
724 {
725 	int i;
726 
727 	for (i = 0; i < 6; i++)
728 		pci_release_region(pdev, i);
729 }
730 
731 /**
732  *	pci_request_regions - Reserved PCI I/O and memory resources
733  *	@pdev: PCI device whose resources are to be reserved
734  *	@res_name: Name to be associated with resource.
735  *
736  *	Mark all PCI regions associated with PCI device @pdev as
737  *	being reserved by owner @res_name.  Do not access any
738  *	address inside the PCI regions unless this call returns
739  *	successfully.
740  *
741  *	Returns 0 on success, or %EBUSY on error.  A warning
742  *	message is also printed on failure.
743  */
744 int pci_request_regions(struct pci_dev *pdev, const char *res_name)
745 {
746 	int i;
747 
748 	for (i = 0; i < 6; i++)
749 		if(pci_request_region(pdev, i, res_name))
750 			goto err_out;
751 	return 0;
752 
753 err_out:
754 	while(--i >= 0)
755 		pci_release_region(pdev, i);
756 
757 	return -EBUSY;
758 }
759 
760 /**
761  * pci_set_master - enables bus-mastering for device dev
762  * @dev: the PCI device to enable
763  *
764  * Enables bus-mastering on the device and calls pcibios_set_master()
765  * to do the needed arch specific settings.
766  */
767 void
768 pci_set_master(struct pci_dev *dev)
769 {
770 	u16 cmd;
771 
772 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
773 	if (! (cmd & PCI_COMMAND_MASTER)) {
774 		pr_debug("PCI: Enabling bus mastering for device %s\n", pci_name(dev));
775 		cmd |= PCI_COMMAND_MASTER;
776 		pci_write_config_word(dev, PCI_COMMAND, cmd);
777 	}
778 	dev->is_busmaster = 1;
779 	pcibios_set_master(dev);
780 }
781 
782 #ifndef HAVE_ARCH_PCI_MWI
783 /* This can be overridden by arch code. */
784 u8 pci_cache_line_size = L1_CACHE_BYTES >> 2;
785 
786 /**
787  * pci_generic_prep_mwi - helper function for pci_set_mwi
788  * @dev: the PCI device for which MWI is enabled
789  *
790  * Helper function for generic implementation of pcibios_prep_mwi
791  * function.  Originally copied from drivers/net/acenic.c.
792  * Copyright 1998-2001 by Jes Sorensen, <jes@trained-monkey.org>.
793  *
794  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
795  */
796 static int
797 pci_generic_prep_mwi(struct pci_dev *dev)
798 {
799 	u8 cacheline_size;
800 
801 	if (!pci_cache_line_size)
802 		return -EINVAL;		/* The system doesn't support MWI. */
803 
804 	/* Validate current setting: the PCI_CACHE_LINE_SIZE must be
805 	   equal to or multiple of the right value. */
806 	pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
807 	if (cacheline_size >= pci_cache_line_size &&
808 	    (cacheline_size % pci_cache_line_size) == 0)
809 		return 0;
810 
811 	/* Write the correct value. */
812 	pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, pci_cache_line_size);
813 	/* Read it back. */
814 	pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &cacheline_size);
815 	if (cacheline_size == pci_cache_line_size)
816 		return 0;
817 
818 	printk(KERN_DEBUG "PCI: cache line size of %d is not supported "
819 	       "by device %s\n", pci_cache_line_size << 2, pci_name(dev));
820 
821 	return -EINVAL;
822 }
823 #endif /* !HAVE_ARCH_PCI_MWI */
824 
825 /**
826  * pci_set_mwi - enables memory-write-invalidate PCI transaction
827  * @dev: the PCI device for which MWI is enabled
828  *
829  * Enables the Memory-Write-Invalidate transaction in %PCI_COMMAND,
830  * and then calls @pcibios_set_mwi to do the needed arch specific
831  * operations or a generic mwi-prep function.
832  *
833  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
834  */
835 int
836 pci_set_mwi(struct pci_dev *dev)
837 {
838 	int rc;
839 	u16 cmd;
840 
841 #ifdef HAVE_ARCH_PCI_MWI
842 	rc = pcibios_prep_mwi(dev);
843 #else
844 	rc = pci_generic_prep_mwi(dev);
845 #endif
846 
847 	if (rc)
848 		return rc;
849 
850 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
851 	if (! (cmd & PCI_COMMAND_INVALIDATE)) {
852 		pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
853 		cmd |= PCI_COMMAND_INVALIDATE;
854 		pci_write_config_word(dev, PCI_COMMAND, cmd);
855 	}
856 
857 	return 0;
858 }
859 
860 /**
861  * pci_clear_mwi - disables Memory-Write-Invalidate for device dev
862  * @dev: the PCI device to disable
863  *
864  * Disables PCI Memory-Write-Invalidate transaction on the device
865  */
866 void
867 pci_clear_mwi(struct pci_dev *dev)
868 {
869 	u16 cmd;
870 
871 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
872 	if (cmd & PCI_COMMAND_INVALIDATE) {
873 		cmd &= ~PCI_COMMAND_INVALIDATE;
874 		pci_write_config_word(dev, PCI_COMMAND, cmd);
875 	}
876 }
877 
878 /**
879  * pci_intx - enables/disables PCI INTx for device dev
880  * @pdev: the PCI device to operate on
881  * @enable: boolean: whether to enable or disable PCI INTx
882  *
883  * Enables/disables PCI INTx for device dev
884  */
885 void
886 pci_intx(struct pci_dev *pdev, int enable)
887 {
888 	u16 pci_command, new;
889 
890 	pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
891 
892 	if (enable) {
893 		new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
894 	} else {
895 		new = pci_command | PCI_COMMAND_INTX_DISABLE;
896 	}
897 
898 	if (new != pci_command) {
899 		pci_write_config_word(pdev, PCI_COMMAND, new);
900 	}
901 }
902 
903 #ifndef HAVE_ARCH_PCI_SET_DMA_MASK
904 /*
905  * These can be overridden by arch-specific implementations
906  */
907 int
908 pci_set_dma_mask(struct pci_dev *dev, u64 mask)
909 {
910 	if (!pci_dma_supported(dev, mask))
911 		return -EIO;
912 
913 	dev->dma_mask = mask;
914 
915 	return 0;
916 }
917 
918 int
919 pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
920 {
921 	if (!pci_dma_supported(dev, mask))
922 		return -EIO;
923 
924 	dev->dev.coherent_dma_mask = mask;
925 
926 	return 0;
927 }
928 #endif
929 
930 static int __devinit pci_init(void)
931 {
932 	struct pci_dev *dev = NULL;
933 
934 	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
935 		pci_fixup_device(pci_fixup_final, dev);
936 	}
937 	return 0;
938 }
939 
940 static int __devinit pci_setup(char *str)
941 {
942 	while (str) {
943 		char *k = strchr(str, ',');
944 		if (k)
945 			*k++ = 0;
946 		if (*str && (str = pcibios_setup(str)) && *str) {
947 			if (!strcmp(str, "nomsi")) {
948 				pci_no_msi();
949 			} else {
950 				printk(KERN_ERR "PCI: Unknown option `%s'\n",
951 						str);
952 			}
953 		}
954 		str = k;
955 	}
956 	return 1;
957 }
958 
959 device_initcall(pci_init);
960 
961 __setup("pci=", pci_setup);
962 
963 #if defined(CONFIG_ISA) || defined(CONFIG_EISA)
964 /* FIXME: Some boxes have multiple ISA bridges! */
965 struct pci_dev *isa_bridge;
966 EXPORT_SYMBOL(isa_bridge);
967 #endif
968 
969 EXPORT_SYMBOL_GPL(pci_restore_bars);
970 EXPORT_SYMBOL(pci_enable_device_bars);
971 EXPORT_SYMBOL(pci_enable_device);
972 EXPORT_SYMBOL(pci_disable_device);
973 EXPORT_SYMBOL(pci_find_capability);
974 EXPORT_SYMBOL(pci_bus_find_capability);
975 EXPORT_SYMBOL(pci_release_regions);
976 EXPORT_SYMBOL(pci_request_regions);
977 EXPORT_SYMBOL(pci_release_region);
978 EXPORT_SYMBOL(pci_request_region);
979 EXPORT_SYMBOL(pci_set_master);
980 EXPORT_SYMBOL(pci_set_mwi);
981 EXPORT_SYMBOL(pci_clear_mwi);
982 EXPORT_SYMBOL_GPL(pci_intx);
983 EXPORT_SYMBOL(pci_set_dma_mask);
984 EXPORT_SYMBOL(pci_set_consistent_dma_mask);
985 EXPORT_SYMBOL(pci_assign_resource);
986 EXPORT_SYMBOL(pci_find_parent_resource);
987 
988 EXPORT_SYMBOL(pci_set_power_state);
989 EXPORT_SYMBOL(pci_save_state);
990 EXPORT_SYMBOL(pci_restore_state);
991 EXPORT_SYMBOL(pci_enable_wake);
992 
993 /* Quirk info */
994 
995 EXPORT_SYMBOL(isa_dma_bridge_buggy);
996 EXPORT_SYMBOL(pci_pci_problems);
997