xref: /openbmc/linux/arch/arm/kernel/bios32.c (revision 7b6d864b)
1 /*
2  *  linux/arch/arm/kernel/bios32.c
3  *
4  *  PCI bios-type initialisation for PCI machines
5  *
6  *  Bits taken from various places.
7  */
8 #include <linux/export.h>
9 #include <linux/kernel.h>
10 #include <linux/pci.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <linux/io.h>
14 
15 #include <asm/mach-types.h>
16 #include <asm/mach/map.h>
17 #include <asm/mach/pci.h>
18 
19 static int debug_pci;
20 
21 /*
22  * We can't use pci_find_device() here since we are
23  * called from interrupt context.
24  */
25 static void pcibios_bus_report_status(struct pci_bus *bus, u_int status_mask, int warn)
26 {
27 	struct pci_dev *dev;
28 
29 	list_for_each_entry(dev, &bus->devices, bus_list) {
30 		u16 status;
31 
32 		/*
33 		 * ignore host bridge - we handle
34 		 * that separately
35 		 */
36 		if (dev->bus->number == 0 && dev->devfn == 0)
37 			continue;
38 
39 		pci_read_config_word(dev, PCI_STATUS, &status);
40 		if (status == 0xffff)
41 			continue;
42 
43 		if ((status & status_mask) == 0)
44 			continue;
45 
46 		/* clear the status errors */
47 		pci_write_config_word(dev, PCI_STATUS, status & status_mask);
48 
49 		if (warn)
50 			printk("(%s: %04X) ", pci_name(dev), status);
51 	}
52 
53 	list_for_each_entry(dev, &bus->devices, bus_list)
54 		if (dev->subordinate)
55 			pcibios_bus_report_status(dev->subordinate, status_mask, warn);
56 }
57 
58 void pcibios_report_status(u_int status_mask, int warn)
59 {
60 	struct list_head *l;
61 
62 	list_for_each(l, &pci_root_buses) {
63 		struct pci_bus *bus = pci_bus_b(l);
64 
65 		pcibios_bus_report_status(bus, status_mask, warn);
66 	}
67 }
68 
69 /*
70  * We don't use this to fix the device, but initialisation of it.
71  * It's not the correct use for this, but it works.
72  * Note that the arbiter/ISA bridge appears to be buggy, specifically in
73  * the following area:
74  * 1. park on CPU
75  * 2. ISA bridge ping-pong
76  * 3. ISA bridge master handling of target RETRY
77  *
78  * Bug 3 is responsible for the sound DMA grinding to a halt.  We now
79  * live with bug 2.
80  */
81 static void pci_fixup_83c553(struct pci_dev *dev)
82 {
83 	/*
84 	 * Set memory region to start at address 0, and enable IO
85 	 */
86 	pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, PCI_BASE_ADDRESS_SPACE_MEMORY);
87 	pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_IO);
88 
89 	dev->resource[0].end -= dev->resource[0].start;
90 	dev->resource[0].start = 0;
91 
92 	/*
93 	 * All memory requests from ISA to be channelled to PCI
94 	 */
95 	pci_write_config_byte(dev, 0x48, 0xff);
96 
97 	/*
98 	 * Enable ping-pong on bus master to ISA bridge transactions.
99 	 * This improves the sound DMA substantially.  The fixed
100 	 * priority arbiter also helps (see below).
101 	 */
102 	pci_write_config_byte(dev, 0x42, 0x01);
103 
104 	/*
105 	 * Enable PCI retry
106 	 */
107 	pci_write_config_byte(dev, 0x40, 0x22);
108 
109 	/*
110 	 * We used to set the arbiter to "park on last master" (bit
111 	 * 1 set), but unfortunately the CyberPro does not park the
112 	 * bus.  We must therefore park on CPU.  Unfortunately, this
113 	 * may trigger yet another bug in the 553.
114 	 */
115 	pci_write_config_byte(dev, 0x83, 0x02);
116 
117 	/*
118 	 * Make the ISA DMA request lowest priority, and disable
119 	 * rotating priorities completely.
120 	 */
121 	pci_write_config_byte(dev, 0x80, 0x11);
122 	pci_write_config_byte(dev, 0x81, 0x00);
123 
124 	/*
125 	 * Route INTA input to IRQ 11, and set IRQ11 to be level
126 	 * sensitive.
127 	 */
128 	pci_write_config_word(dev, 0x44, 0xb000);
129 	outb(0x08, 0x4d1);
130 }
131 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_83C553, pci_fixup_83c553);
132 
133 static void pci_fixup_unassign(struct pci_dev *dev)
134 {
135 	dev->resource[0].end -= dev->resource[0].start;
136 	dev->resource[0].start = 0;
137 }
138 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND2, PCI_DEVICE_ID_WINBOND2_89C940F, pci_fixup_unassign);
139 
140 /*
141  * Prevent the PCI layer from seeing the resources allocated to this device
142  * if it is the host bridge by marking it as such.  These resources are of
143  * no consequence to the PCI layer (they are handled elsewhere).
144  */
145 static void pci_fixup_dec21285(struct pci_dev *dev)
146 {
147 	int i;
148 
149 	if (dev->devfn == 0) {
150 		dev->class &= 0xff;
151 		dev->class |= PCI_CLASS_BRIDGE_HOST << 8;
152 		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
153 			dev->resource[i].start = 0;
154 			dev->resource[i].end   = 0;
155 			dev->resource[i].flags = 0;
156 		}
157 	}
158 }
159 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21285, pci_fixup_dec21285);
160 
161 /*
162  * PCI IDE controllers use non-standard I/O port decoding, respect it.
163  */
164 static void pci_fixup_ide_bases(struct pci_dev *dev)
165 {
166 	struct resource *r;
167 	int i;
168 
169 	if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
170 		return;
171 
172 	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
173 		r = dev->resource + i;
174 		if ((r->start & ~0x80) == 0x374) {
175 			r->start |= 2;
176 			r->end = r->start;
177 		}
178 	}
179 }
180 DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pci_fixup_ide_bases);
181 
182 /*
183  * Put the DEC21142 to sleep
184  */
185 static void pci_fixup_dec21142(struct pci_dev *dev)
186 {
187 	pci_write_config_dword(dev, 0x40, 0x80000000);
188 }
189 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21142, pci_fixup_dec21142);
190 
191 /*
192  * The CY82C693 needs some rather major fixups to ensure that it does
193  * the right thing.  Idea from the Alpha people, with a few additions.
194  *
195  * We ensure that the IDE base registers are set to 1f0/3f4 for the
196  * primary bus, and 170/374 for the secondary bus.  Also, hide them
197  * from the PCI subsystem view as well so we won't try to perform
198  * our own auto-configuration on them.
199  *
200  * In addition, we ensure that the PCI IDE interrupts are routed to
201  * IRQ 14 and IRQ 15 respectively.
202  *
203  * The above gets us to a point where the IDE on this device is
204  * functional.  However, The CY82C693U _does not work_ in bus
205  * master mode without locking the PCI bus solid.
206  */
207 static void pci_fixup_cy82c693(struct pci_dev *dev)
208 {
209 	if ((dev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
210 		u32 base0, base1;
211 
212 		if (dev->class & 0x80) {	/* primary */
213 			base0 = 0x1f0;
214 			base1 = 0x3f4;
215 		} else {			/* secondary */
216 			base0 = 0x170;
217 			base1 = 0x374;
218 		}
219 
220 		pci_write_config_dword(dev, PCI_BASE_ADDRESS_0,
221 				       base0 | PCI_BASE_ADDRESS_SPACE_IO);
222 		pci_write_config_dword(dev, PCI_BASE_ADDRESS_1,
223 				       base1 | PCI_BASE_ADDRESS_SPACE_IO);
224 
225 		dev->resource[0].start = 0;
226 		dev->resource[0].end   = 0;
227 		dev->resource[0].flags = 0;
228 
229 		dev->resource[1].start = 0;
230 		dev->resource[1].end   = 0;
231 		dev->resource[1].flags = 0;
232 	} else if (PCI_FUNC(dev->devfn) == 0) {
233 		/*
234 		 * Setup IDE IRQ routing.
235 		 */
236 		pci_write_config_byte(dev, 0x4b, 14);
237 		pci_write_config_byte(dev, 0x4c, 15);
238 
239 		/*
240 		 * Disable FREQACK handshake, enable USB.
241 		 */
242 		pci_write_config_byte(dev, 0x4d, 0x41);
243 
244 		/*
245 		 * Enable PCI retry, and PCI post-write buffer.
246 		 */
247 		pci_write_config_byte(dev, 0x44, 0x17);
248 
249 		/*
250 		 * Enable ISA master and DMA post write buffering.
251 		 */
252 		pci_write_config_byte(dev, 0x45, 0x03);
253 	}
254 }
255 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CONTAQ, PCI_DEVICE_ID_CONTAQ_82C693, pci_fixup_cy82c693);
256 
257 static void pci_fixup_it8152(struct pci_dev *dev)
258 {
259 	int i;
260 	/* fixup for ITE 8152 devices */
261 	/* FIXME: add defines for class 0x68000 and 0x80103 */
262 	if ((dev->class >> 8) == PCI_CLASS_BRIDGE_HOST ||
263 	    dev->class == 0x68000 ||
264 	    dev->class == 0x80103) {
265 		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
266 			dev->resource[i].start = 0;
267 			dev->resource[i].end   = 0;
268 			dev->resource[i].flags = 0;
269 		}
270 	}
271 }
272 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ITE, PCI_DEVICE_ID_ITE_8152, pci_fixup_it8152);
273 
274 /*
275  * If the bus contains any of these devices, then we must not turn on
276  * parity checking of any kind.  Currently this is CyberPro 20x0 only.
277  */
278 static inline int pdev_bad_for_parity(struct pci_dev *dev)
279 {
280 	return ((dev->vendor == PCI_VENDOR_ID_INTERG &&
281 		 (dev->device == PCI_DEVICE_ID_INTERG_2000 ||
282 		  dev->device == PCI_DEVICE_ID_INTERG_2010)) ||
283 		(dev->vendor == PCI_VENDOR_ID_ITE &&
284 		 dev->device == PCI_DEVICE_ID_ITE_8152));
285 
286 }
287 
288 /*
289  * pcibios_fixup_bus - Called after each bus is probed,
290  * but before its children are examined.
291  */
292 void pcibios_fixup_bus(struct pci_bus *bus)
293 {
294 	struct pci_dev *dev;
295 	u16 features = PCI_COMMAND_SERR | PCI_COMMAND_PARITY | PCI_COMMAND_FAST_BACK;
296 
297 	/*
298 	 * Walk the devices on this bus, working out what we can
299 	 * and can't support.
300 	 */
301 	list_for_each_entry(dev, &bus->devices, bus_list) {
302 		u16 status;
303 
304 		pci_read_config_word(dev, PCI_STATUS, &status);
305 
306 		/*
307 		 * If any device on this bus does not support fast back
308 		 * to back transfers, then the bus as a whole is not able
309 		 * to support them.  Having fast back to back transfers
310 		 * on saves us one PCI cycle per transaction.
311 		 */
312 		if (!(status & PCI_STATUS_FAST_BACK))
313 			features &= ~PCI_COMMAND_FAST_BACK;
314 
315 		if (pdev_bad_for_parity(dev))
316 			features &= ~(PCI_COMMAND_SERR | PCI_COMMAND_PARITY);
317 
318 		switch (dev->class >> 8) {
319 		case PCI_CLASS_BRIDGE_PCI:
320 			pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &status);
321 			status |= PCI_BRIDGE_CTL_PARITY|PCI_BRIDGE_CTL_MASTER_ABORT;
322 			status &= ~(PCI_BRIDGE_CTL_BUS_RESET|PCI_BRIDGE_CTL_FAST_BACK);
323 			pci_write_config_word(dev, PCI_BRIDGE_CONTROL, status);
324 			break;
325 
326 		case PCI_CLASS_BRIDGE_CARDBUS:
327 			pci_read_config_word(dev, PCI_CB_BRIDGE_CONTROL, &status);
328 			status |= PCI_CB_BRIDGE_CTL_PARITY|PCI_CB_BRIDGE_CTL_MASTER_ABORT;
329 			pci_write_config_word(dev, PCI_CB_BRIDGE_CONTROL, status);
330 			break;
331 		}
332 	}
333 
334 	/*
335 	 * Now walk the devices again, this time setting them up.
336 	 */
337 	list_for_each_entry(dev, &bus->devices, bus_list) {
338 		u16 cmd;
339 
340 		pci_read_config_word(dev, PCI_COMMAND, &cmd);
341 		cmd |= features;
342 		pci_write_config_word(dev, PCI_COMMAND, cmd);
343 
344 		pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE,
345 				      L1_CACHE_BYTES >> 2);
346 	}
347 
348 	/*
349 	 * Propagate the flags to the PCI bridge.
350 	 */
351 	if (bus->self && bus->self->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
352 		if (features & PCI_COMMAND_FAST_BACK)
353 			bus->bridge_ctl |= PCI_BRIDGE_CTL_FAST_BACK;
354 		if (features & PCI_COMMAND_PARITY)
355 			bus->bridge_ctl |= PCI_BRIDGE_CTL_PARITY;
356 	}
357 
358 	/*
359 	 * Report what we did for this bus
360 	 */
361 	printk(KERN_INFO "PCI: bus%d: Fast back to back transfers %sabled\n",
362 		bus->number, (features & PCI_COMMAND_FAST_BACK) ? "en" : "dis");
363 }
364 EXPORT_SYMBOL(pcibios_fixup_bus);
365 
366 /*
367  * Swizzle the device pin each time we cross a bridge.  If a platform does
368  * not provide a swizzle function, we perform the standard PCI swizzling.
369  *
370  * The default swizzling walks up the bus tree one level at a time, applying
371  * the standard swizzle function at each step, stopping when it finds the PCI
372  * root bus.  This will return the slot number of the bridge device on the
373  * root bus and the interrupt pin on that device which should correspond
374  * with the downstream device interrupt.
375  *
376  * Platforms may override this, in which case the slot and pin returned
377  * depend entirely on the platform code.  However, please note that the
378  * PCI standard swizzle is implemented on plug-in cards and Cardbus based
379  * PCI extenders, so it can not be ignored.
380  */
381 static u8 pcibios_swizzle(struct pci_dev *dev, u8 *pin)
382 {
383 	struct pci_sys_data *sys = dev->sysdata;
384 	int slot, oldpin = *pin;
385 
386 	if (sys->swizzle)
387 		slot = sys->swizzle(dev, pin);
388 	else
389 		slot = pci_common_swizzle(dev, pin);
390 
391 	if (debug_pci)
392 		printk("PCI: %s swizzling pin %d => pin %d slot %d\n",
393 			pci_name(dev), oldpin, *pin, slot);
394 
395 	return slot;
396 }
397 
398 /*
399  * Map a slot/pin to an IRQ.
400  */
401 static int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
402 {
403 	struct pci_sys_data *sys = dev->sysdata;
404 	int irq = -1;
405 
406 	if (sys->map_irq)
407 		irq = sys->map_irq(dev, slot, pin);
408 
409 	if (debug_pci)
410 		printk("PCI: %s mapping slot %d pin %d => irq %d\n",
411 			pci_name(dev), slot, pin, irq);
412 
413 	return irq;
414 }
415 
416 static int pcibios_init_resources(int busnr, struct pci_sys_data *sys)
417 {
418 	int ret;
419 	struct pci_host_bridge_window *window;
420 
421 	if (list_empty(&sys->resources)) {
422 		pci_add_resource_offset(&sys->resources,
423 			 &iomem_resource, sys->mem_offset);
424 	}
425 
426 	list_for_each_entry(window, &sys->resources, list) {
427 		if (resource_type(window->res) == IORESOURCE_IO)
428 			return 0;
429 	}
430 
431 	sys->io_res.start = (busnr * SZ_64K) ?  : pcibios_min_io;
432 	sys->io_res.end = (busnr + 1) * SZ_64K - 1;
433 	sys->io_res.flags = IORESOURCE_IO;
434 	sys->io_res.name = sys->io_res_name;
435 	sprintf(sys->io_res_name, "PCI%d I/O", busnr);
436 
437 	ret = request_resource(&ioport_resource, &sys->io_res);
438 	if (ret) {
439 		pr_err("PCI: unable to allocate I/O port region (%d)\n", ret);
440 		return ret;
441 	}
442 	pci_add_resource_offset(&sys->resources, &sys->io_res,
443 				sys->io_offset);
444 
445 	return 0;
446 }
447 
448 static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
449 			    struct list_head *head)
450 {
451 	struct pci_sys_data *sys = NULL;
452 	int ret;
453 	int nr, busnr;
454 
455 	for (nr = busnr = 0; nr < hw->nr_controllers; nr++) {
456 		sys = kzalloc(sizeof(struct pci_sys_data), GFP_KERNEL);
457 		if (!sys)
458 			panic("PCI: unable to allocate sys data!");
459 
460 #ifdef CONFIG_PCI_DOMAINS
461 		sys->domain  = hw->domain;
462 #endif
463 		sys->busnr   = busnr;
464 		sys->swizzle = hw->swizzle;
465 		sys->map_irq = hw->map_irq;
466 		sys->align_resource = hw->align_resource;
467 		INIT_LIST_HEAD(&sys->resources);
468 
469 		if (hw->private_data)
470 			sys->private_data = hw->private_data[nr];
471 
472 		ret = hw->setup(nr, sys);
473 
474 		if (ret > 0) {
475 			ret = pcibios_init_resources(nr, sys);
476 			if (ret)  {
477 				kfree(sys);
478 				break;
479 			}
480 
481 			if (hw->scan)
482 				sys->bus = hw->scan(nr, sys);
483 			else
484 				sys->bus = pci_scan_root_bus(parent, sys->busnr,
485 						hw->ops, sys, &sys->resources);
486 
487 			if (!sys->bus)
488 				panic("PCI: unable to scan bus!");
489 
490 			busnr = sys->bus->busn_res.end + 1;
491 
492 			list_add(&sys->node, head);
493 		} else {
494 			kfree(sys);
495 			if (ret < 0)
496 				break;
497 		}
498 	}
499 }
500 
501 void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
502 {
503 	struct pci_sys_data *sys;
504 	LIST_HEAD(head);
505 
506 	pci_add_flags(PCI_REASSIGN_ALL_RSRC);
507 	if (hw->preinit)
508 		hw->preinit();
509 	pcibios_init_hw(parent, hw, &head);
510 	if (hw->postinit)
511 		hw->postinit();
512 
513 	pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
514 
515 	list_for_each_entry(sys, &head, node) {
516 		struct pci_bus *bus = sys->bus;
517 
518 		if (!pci_has_flag(PCI_PROBE_ONLY)) {
519 			/*
520 			 * Size the bridge windows.
521 			 */
522 			pci_bus_size_bridges(bus);
523 
524 			/*
525 			 * Assign resources.
526 			 */
527 			pci_bus_assign_resources(bus);
528 
529 			/*
530 			 * Enable bridges
531 			 */
532 			pci_enable_bridges(bus);
533 		}
534 
535 		/*
536 		 * Tell drivers about devices found.
537 		 */
538 		pci_bus_add_devices(bus);
539 	}
540 }
541 
542 #ifndef CONFIG_PCI_HOST_ITE8152
543 void pcibios_set_master(struct pci_dev *dev)
544 {
545 	/* No special bus mastering setup handling */
546 }
547 #endif
548 
549 char * __init pcibios_setup(char *str)
550 {
551 	if (!strcmp(str, "debug")) {
552 		debug_pci = 1;
553 		return NULL;
554 	} else if (!strcmp(str, "firmware")) {
555 		pci_add_flags(PCI_PROBE_ONLY);
556 		return NULL;
557 	}
558 	return str;
559 }
560 
561 /*
562  * From arch/i386/kernel/pci-i386.c:
563  *
564  * We need to avoid collisions with `mirrored' VGA ports
565  * and other strange ISA hardware, so we always want the
566  * addresses to be allocated in the 0x000-0x0ff region
567  * modulo 0x400.
568  *
569  * Why? Because some silly external IO cards only decode
570  * the low 10 bits of the IO address. The 0x00-0xff region
571  * is reserved for motherboard devices that decode all 16
572  * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
573  * but we want to try to avoid allocating at 0x2900-0x2bff
574  * which might be mirrored at 0x0100-0x03ff..
575  */
576 resource_size_t pcibios_align_resource(void *data, const struct resource *res,
577 				resource_size_t size, resource_size_t align)
578 {
579 	struct pci_dev *dev = data;
580 	struct pci_sys_data *sys = dev->sysdata;
581 	resource_size_t start = res->start;
582 
583 	if (res->flags & IORESOURCE_IO && start & 0x300)
584 		start = (start + 0x3ff) & ~0x3ff;
585 
586 	start = (start + align - 1) & ~(align - 1);
587 
588 	if (sys->align_resource)
589 		return sys->align_resource(dev, res, start, size, align);
590 
591 	return start;
592 }
593 
594 /**
595  * pcibios_enable_device - Enable I/O and memory.
596  * @dev: PCI device to be enabled
597  */
598 int pcibios_enable_device(struct pci_dev *dev, int mask)
599 {
600 	u16 cmd, old_cmd;
601 	int idx;
602 	struct resource *r;
603 
604 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
605 	old_cmd = cmd;
606 	for (idx = 0; idx < 6; idx++) {
607 		/* Only set up the requested stuff */
608 		if (!(mask & (1 << idx)))
609 			continue;
610 
611 		r = dev->resource + idx;
612 		if (!r->start && r->end) {
613 			printk(KERN_ERR "PCI: Device %s not available because"
614 			       " of resource collisions\n", pci_name(dev));
615 			return -EINVAL;
616 		}
617 		if (r->flags & IORESOURCE_IO)
618 			cmd |= PCI_COMMAND_IO;
619 		if (r->flags & IORESOURCE_MEM)
620 			cmd |= PCI_COMMAND_MEMORY;
621 	}
622 
623 	/*
624 	 * Bridges (eg, cardbus bridges) need to be fully enabled
625 	 */
626 	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
627 		cmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
628 
629 	if (cmd != old_cmd) {
630 		printk("PCI: enabling device %s (%04x -> %04x)\n",
631 		       pci_name(dev), old_cmd, cmd);
632 		pci_write_config_word(dev, PCI_COMMAND, cmd);
633 	}
634 	return 0;
635 }
636 
637 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
638 			enum pci_mmap_state mmap_state, int write_combine)
639 {
640 	struct pci_sys_data *root = dev->sysdata;
641 	unsigned long phys;
642 
643 	if (mmap_state == pci_mmap_io) {
644 		return -EINVAL;
645 	} else {
646 		phys = vma->vm_pgoff + (root->mem_offset >> PAGE_SHIFT);
647 	}
648 
649 	/*
650 	 * Mark this as IO
651 	 */
652 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
653 
654 	if (remap_pfn_range(vma, vma->vm_start, phys,
655 			     vma->vm_end - vma->vm_start,
656 			     vma->vm_page_prot))
657 		return -EAGAIN;
658 
659 	return 0;
660 }
661 
662 void __init pci_map_io_early(unsigned long pfn)
663 {
664 	struct map_desc pci_io_desc = {
665 		.virtual	= PCI_IO_VIRT_BASE,
666 		.type		= MT_DEVICE,
667 		.length		= SZ_64K,
668 	};
669 
670 	pci_io_desc.pfn = pfn;
671 	iotable_init(&pci_io_desc, 1);
672 }
673