xref: /linux/arch/arm/kernel/bios32.c (revision b43ab901d671e3e3cad425ea5e9a3c74e266dcdd)
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/pci.h>
17 
18 static int debug_pci;
19 static int use_firmware;
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 __devinit 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 __devinit 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 __devinit 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 __devinit 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 __devinit 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 __devinit 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 __init 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 
276 void __devinit pcibios_update_irq(struct pci_dev *dev, int irq)
277 {
278 	if (debug_pci)
279 		printk("PCI: Assigning IRQ %02d to %s\n", irq, pci_name(dev));
280 	pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
281 }
282 
283 /*
284  * If the bus contains any of these devices, then we must not turn on
285  * parity checking of any kind.  Currently this is CyberPro 20x0 only.
286  */
287 static inline int pdev_bad_for_parity(struct pci_dev *dev)
288 {
289 	return ((dev->vendor == PCI_VENDOR_ID_INTERG &&
290 		 (dev->device == PCI_DEVICE_ID_INTERG_2000 ||
291 		  dev->device == PCI_DEVICE_ID_INTERG_2010)) ||
292 		(dev->vendor == PCI_VENDOR_ID_ITE &&
293 		 dev->device == PCI_DEVICE_ID_ITE_8152));
294 
295 }
296 
297 /*
298  * Adjust the device resources from bus-centric to Linux-centric.
299  */
300 static void __devinit
301 pdev_fixup_device_resources(struct pci_sys_data *root, struct pci_dev *dev)
302 {
303 	resource_size_t offset;
304 	int i;
305 
306 	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
307 		if (dev->resource[i].start == 0)
308 			continue;
309 		if (dev->resource[i].flags & IORESOURCE_MEM)
310 			offset = root->mem_offset;
311 		else
312 			offset = root->io_offset;
313 
314 		dev->resource[i].start += offset;
315 		dev->resource[i].end   += offset;
316 	}
317 }
318 
319 /*
320  * pcibios_fixup_bus - Called after each bus is probed,
321  * but before its children are examined.
322  */
323 void pcibios_fixup_bus(struct pci_bus *bus)
324 {
325 	struct pci_sys_data *root = bus->sysdata;
326 	struct pci_dev *dev;
327 	u16 features = PCI_COMMAND_SERR | PCI_COMMAND_PARITY | PCI_COMMAND_FAST_BACK;
328 
329 	/*
330 	 * Walk the devices on this bus, working out what we can
331 	 * and can't support.
332 	 */
333 	list_for_each_entry(dev, &bus->devices, bus_list) {
334 		u16 status;
335 
336 		pdev_fixup_device_resources(root, dev);
337 
338 		pci_read_config_word(dev, PCI_STATUS, &status);
339 
340 		/*
341 		 * If any device on this bus does not support fast back
342 		 * to back transfers, then the bus as a whole is not able
343 		 * to support them.  Having fast back to back transfers
344 		 * on saves us one PCI cycle per transaction.
345 		 */
346 		if (!(status & PCI_STATUS_FAST_BACK))
347 			features &= ~PCI_COMMAND_FAST_BACK;
348 
349 		if (pdev_bad_for_parity(dev))
350 			features &= ~(PCI_COMMAND_SERR | PCI_COMMAND_PARITY);
351 
352 		switch (dev->class >> 8) {
353 		case PCI_CLASS_BRIDGE_PCI:
354 			pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &status);
355 			status |= PCI_BRIDGE_CTL_PARITY|PCI_BRIDGE_CTL_MASTER_ABORT;
356 			status &= ~(PCI_BRIDGE_CTL_BUS_RESET|PCI_BRIDGE_CTL_FAST_BACK);
357 			pci_write_config_word(dev, PCI_BRIDGE_CONTROL, status);
358 			break;
359 
360 		case PCI_CLASS_BRIDGE_CARDBUS:
361 			pci_read_config_word(dev, PCI_CB_BRIDGE_CONTROL, &status);
362 			status |= PCI_CB_BRIDGE_CTL_PARITY|PCI_CB_BRIDGE_CTL_MASTER_ABORT;
363 			pci_write_config_word(dev, PCI_CB_BRIDGE_CONTROL, status);
364 			break;
365 		}
366 	}
367 
368 	/*
369 	 * Now walk the devices again, this time setting them up.
370 	 */
371 	list_for_each_entry(dev, &bus->devices, bus_list) {
372 		u16 cmd;
373 
374 		pci_read_config_word(dev, PCI_COMMAND, &cmd);
375 		cmd |= features;
376 		pci_write_config_word(dev, PCI_COMMAND, cmd);
377 
378 		pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE,
379 				      L1_CACHE_BYTES >> 2);
380 	}
381 
382 	/*
383 	 * Propagate the flags to the PCI bridge.
384 	 */
385 	if (bus->self && bus->self->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
386 		if (features & PCI_COMMAND_FAST_BACK)
387 			bus->bridge_ctl |= PCI_BRIDGE_CTL_FAST_BACK;
388 		if (features & PCI_COMMAND_PARITY)
389 			bus->bridge_ctl |= PCI_BRIDGE_CTL_PARITY;
390 	}
391 
392 	/*
393 	 * Report what we did for this bus
394 	 */
395 	printk(KERN_INFO "PCI: bus%d: Fast back to back transfers %sabled\n",
396 		bus->number, (features & PCI_COMMAND_FAST_BACK) ? "en" : "dis");
397 }
398 #ifdef CONFIG_HOTPLUG
399 EXPORT_SYMBOL(pcibios_fixup_bus);
400 #endif
401 
402 /*
403  * Convert from Linux-centric to bus-centric addresses for bridge devices.
404  */
405 void
406 pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
407 			 struct resource *res)
408 {
409 	struct pci_sys_data *root = dev->sysdata;
410 	unsigned long offset = 0;
411 
412 	if (res->flags & IORESOURCE_IO)
413 		offset = root->io_offset;
414 	if (res->flags & IORESOURCE_MEM)
415 		offset = root->mem_offset;
416 
417 	region->start = res->start - offset;
418 	region->end   = res->end - offset;
419 }
420 EXPORT_SYMBOL(pcibios_resource_to_bus);
421 
422 void __devinit
423 pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
424 			struct pci_bus_region *region)
425 {
426 	struct pci_sys_data *root = dev->sysdata;
427 	unsigned long offset = 0;
428 
429 	if (res->flags & IORESOURCE_IO)
430 		offset = root->io_offset;
431 	if (res->flags & IORESOURCE_MEM)
432 		offset = root->mem_offset;
433 
434 	res->start = region->start + offset;
435 	res->end   = region->end + offset;
436 }
437 EXPORT_SYMBOL(pcibios_bus_to_resource);
438 
439 /*
440  * Swizzle the device pin each time we cross a bridge.
441  * This might update pin and returns the slot number.
442  */
443 static u8 __devinit pcibios_swizzle(struct pci_dev *dev, u8 *pin)
444 {
445 	struct pci_sys_data *sys = dev->sysdata;
446 	int slot = 0, oldpin = *pin;
447 
448 	if (sys->swizzle)
449 		slot = sys->swizzle(dev, pin);
450 
451 	if (debug_pci)
452 		printk("PCI: %s swizzling pin %d => pin %d slot %d\n",
453 			pci_name(dev), oldpin, *pin, slot);
454 
455 	return slot;
456 }
457 
458 /*
459  * Map a slot/pin to an IRQ.
460  */
461 static int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
462 {
463 	struct pci_sys_data *sys = dev->sysdata;
464 	int irq = -1;
465 
466 	if (sys->map_irq)
467 		irq = sys->map_irq(dev, slot, pin);
468 
469 	if (debug_pci)
470 		printk("PCI: %s mapping slot %d pin %d => irq %d\n",
471 			pci_name(dev), slot, pin, irq);
472 
473 	return irq;
474 }
475 
476 static void __init pcibios_init_hw(struct hw_pci *hw)
477 {
478 	struct pci_sys_data *sys = NULL;
479 	int ret;
480 	int nr, busnr;
481 
482 	for (nr = busnr = 0; nr < hw->nr_controllers; nr++) {
483 		sys = kzalloc(sizeof(struct pci_sys_data), GFP_KERNEL);
484 		if (!sys)
485 			panic("PCI: unable to allocate sys data!");
486 
487 #ifdef CONFIG_PCI_DOMAINS
488 		sys->domain  = hw->domain;
489 #endif
490 		sys->hw      = hw;
491 		sys->busnr   = busnr;
492 		sys->swizzle = hw->swizzle;
493 		sys->map_irq = hw->map_irq;
494 		INIT_LIST_HEAD(&sys->resources);
495 
496 		ret = hw->setup(nr, sys);
497 
498 		if (ret > 0) {
499 			if (list_empty(&sys->resources)) {
500 				pci_add_resource(&sys->resources,
501 						 &ioport_resource);
502 				pci_add_resource(&sys->resources,
503 						 &iomem_resource);
504 			}
505 
506 			sys->bus = hw->scan(nr, sys);
507 
508 			if (!sys->bus)
509 				panic("PCI: unable to scan bus!");
510 
511 			busnr = sys->bus->subordinate + 1;
512 
513 			list_add(&sys->node, &hw->buses);
514 		} else {
515 			kfree(sys);
516 			if (ret < 0)
517 				break;
518 		}
519 	}
520 }
521 
522 void __init pci_common_init(struct hw_pci *hw)
523 {
524 	struct pci_sys_data *sys;
525 
526 	INIT_LIST_HEAD(&hw->buses);
527 
528 	if (hw->preinit)
529 		hw->preinit();
530 	pcibios_init_hw(hw);
531 	if (hw->postinit)
532 		hw->postinit();
533 
534 	pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
535 
536 	list_for_each_entry(sys, &hw->buses, node) {
537 		struct pci_bus *bus = sys->bus;
538 
539 		if (!use_firmware) {
540 			/*
541 			 * Size the bridge windows.
542 			 */
543 			pci_bus_size_bridges(bus);
544 
545 			/*
546 			 * Assign resources.
547 			 */
548 			pci_bus_assign_resources(bus);
549 
550 			/*
551 			 * Enable bridges
552 			 */
553 			pci_enable_bridges(bus);
554 		}
555 
556 		/*
557 		 * Tell drivers about devices found.
558 		 */
559 		pci_bus_add_devices(bus);
560 	}
561 }
562 
563 #ifndef CONFIG_PCI_HOST_ITE8152
564 void pcibios_set_master(struct pci_dev *dev)
565 {
566 	/* No special bus mastering setup handling */
567 }
568 #endif
569 
570 char * __init pcibios_setup(char *str)
571 {
572 	if (!strcmp(str, "debug")) {
573 		debug_pci = 1;
574 		return NULL;
575 	} else if (!strcmp(str, "firmware")) {
576 		use_firmware = 1;
577 		return NULL;
578 	}
579 	return str;
580 }
581 
582 /*
583  * From arch/i386/kernel/pci-i386.c:
584  *
585  * We need to avoid collisions with `mirrored' VGA ports
586  * and other strange ISA hardware, so we always want the
587  * addresses to be allocated in the 0x000-0x0ff region
588  * modulo 0x400.
589  *
590  * Why? Because some silly external IO cards only decode
591  * the low 10 bits of the IO address. The 0x00-0xff region
592  * is reserved for motherboard devices that decode all 16
593  * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
594  * but we want to try to avoid allocating at 0x2900-0x2bff
595  * which might be mirrored at 0x0100-0x03ff..
596  */
597 resource_size_t pcibios_align_resource(void *data, const struct resource *res,
598 				resource_size_t size, resource_size_t align)
599 {
600 	resource_size_t start = res->start;
601 
602 	if (res->flags & IORESOURCE_IO && start & 0x300)
603 		start = (start + 0x3ff) & ~0x3ff;
604 
605 	start = (start + align - 1) & ~(align - 1);
606 
607 	return start;
608 }
609 
610 /**
611  * pcibios_enable_device - Enable I/O and memory.
612  * @dev: PCI device to be enabled
613  */
614 int pcibios_enable_device(struct pci_dev *dev, int mask)
615 {
616 	u16 cmd, old_cmd;
617 	int idx;
618 	struct resource *r;
619 
620 	pci_read_config_word(dev, PCI_COMMAND, &cmd);
621 	old_cmd = cmd;
622 	for (idx = 0; idx < 6; idx++) {
623 		/* Only set up the requested stuff */
624 		if (!(mask & (1 << idx)))
625 			continue;
626 
627 		r = dev->resource + idx;
628 		if (!r->start && r->end) {
629 			printk(KERN_ERR "PCI: Device %s not available because"
630 			       " of resource collisions\n", pci_name(dev));
631 			return -EINVAL;
632 		}
633 		if (r->flags & IORESOURCE_IO)
634 			cmd |= PCI_COMMAND_IO;
635 		if (r->flags & IORESOURCE_MEM)
636 			cmd |= PCI_COMMAND_MEMORY;
637 	}
638 
639 	/*
640 	 * Bridges (eg, cardbus bridges) need to be fully enabled
641 	 */
642 	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
643 		cmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
644 
645 	if (cmd != old_cmd) {
646 		printk("PCI: enabling device %s (%04x -> %04x)\n",
647 		       pci_name(dev), old_cmd, cmd);
648 		pci_write_config_word(dev, PCI_COMMAND, cmd);
649 	}
650 	return 0;
651 }
652 
653 int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
654 			enum pci_mmap_state mmap_state, int write_combine)
655 {
656 	struct pci_sys_data *root = dev->sysdata;
657 	unsigned long phys;
658 
659 	if (mmap_state == pci_mmap_io) {
660 		return -EINVAL;
661 	} else {
662 		phys = vma->vm_pgoff + (root->mem_offset >> PAGE_SHIFT);
663 	}
664 
665 	/*
666 	 * Mark this as IO
667 	 */
668 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
669 
670 	if (remap_pfn_range(vma, vma->vm_start, phys,
671 			     vma->vm_end - vma->vm_start,
672 			     vma->vm_page_prot))
673 		return -EAGAIN;
674 
675 	return 0;
676 }
677