arch/x86/kernel/aperture_64.c - android_kernel_oneplus_sm8150 - Gitiles

 /*
  * Firmware replacement code.
  *
  * Work around broken BIOSes that don't set an aperture or only set the
  * aperture in the AGP bridge.
  * If all fails map the aperture over some low memory.  This is cheaper than
  * doing bounce buffering. The memory is lost. This is done at early boot
  * because only the bootmem allocator can allocate 32+MB.
  *
  * Copyright 2002 Andi Kleen, SuSE Labs.
  */
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/bootmem.h>
 #include <linux/mmzone.h>
 #include <linux/pci_ids.h>
 #include <linux/pci.h>
 #include <linux/bitops.h>
 #include <linux/ioport.h>
 #include <linux/suspend.h>
 #include <asm/e820.h>
 #include <asm/io.h>
 #include <asm/gart.h>
 #include <asm/pci-direct.h>
 #include <asm/dma.h>
 #include <asm/k8.h>

 int gart_iommu_aperture;
 int gart_iommu_aperture_disabled __initdata;
 int gart_iommu_aperture_allowed __initdata;

 int fallback_aper_order __initdata = 1; /* 64MB */
 int fallback_aper_force __initdata;

 int fix_aperture __initdata = 1;

 static struct resource gart_resource = {
 	.name	= "GART",
 	.flags	= IORESOURCE_MEM,
 };

 static void __init insert_aperture_resource(u32 aper_base, u32 aper_size)
 {
 	gart_resource.start = aper_base;
 	gart_resource.end = aper_base + aper_size - 1;
 	insert_resource(&iomem_resource, &gart_resource);
 }

 /* This code runs before the PCI subsystem is initialized, so just
    access the northbridge directly. */

 static u32 __init allocate_aperture(void)
 {
 	u32 aper_size;
 	void *p;

 	if (fallback_aper_order > 7)
 		fallback_aper_order = 7;
 	aper_size = (32 * 1024 * 1024) << fallback_aper_order;

 	/*
 	 * Aperture has to be naturally aligned. This means a 2GB aperture
 	 * won't have much chance of finding a place in the lower 4GB of
 	 * memory. Unfortunately we cannot move it up because that would
 	 * make the IOMMU useless.
 	 */
 	p = __alloc_bootmem_nopanic(aper_size, aper_size, 0);
 	if (!p || __pa(p)+aper_size > 0xffffffff) {
 		printk(KERN_ERR
 			"Cannot allocate aperture memory hole (%p,%uK)\n",
 				p, aper_size>>10);
 		if (p)
 			free_bootmem(__pa(p), aper_size);
 		return 0;
 	}
 	printk(KERN_INFO "Mapping aperture over %d KB of RAM @ %lx\n",
 			aper_size >> 10, __pa(p));
 	insert_aperture_resource((u32)__pa(p), aper_size);
 	register_nosave_region((u32)__pa(p) >> PAGE_SHIFT,
 				(u32)__pa(p+aper_size) >> PAGE_SHIFT);

 	return (u32)__pa(p);
 }

 static int __init aperture_valid(u64 aper_base, u32 aper_size)
 {
 	if (!aper_base)
 		return 0;

 	if (aper_base + aper_size > 0x100000000UL) {
 		printk(KERN_ERR "Aperture beyond 4GB. Ignoring.\n");
 		return 0;
 	}
 	if (e820_any_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
 		printk(KERN_ERR "Aperture pointing to e820 RAM. Ignoring.\n");
 		return 0;
 	}
 	if (aper_size < 64*1024*1024) {
 		printk(KERN_ERR "Aperture too small (%d MB)\n", aper_size>>20);
 		return 0;
 	}

 	return 1;
 }

 /* Find a PCI capability */
 static __u32 __init find_cap(int num, int slot, int func, int cap)
 {
 	int bytes;
 	u8 pos;

 	if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
 						PCI_STATUS_CAP_LIST))
 		return 0;

 	pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
 	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
 		u8 id;

 		pos &= ~3;
 		id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
 		if (id == 0xff)
 			break;
 		if (id == cap)
 			return pos;
 		pos = read_pci_config_byte(num, slot, func,
 						pos+PCI_CAP_LIST_NEXT);
 	}
 	return 0;
 }

 /* Read a standard AGPv3 bridge header */
 static __u32 __init read_agp(int num, int slot, int func, int cap, u32 *order)
 {
 	u32 apsize;
 	u32 apsizereg;
 	int nbits;
 	u32 aper_low, aper_hi;
 	u64 aper;

 	printk(KERN_INFO "AGP bridge at %02x:%02x:%02x\n", num, slot, func);
 	apsizereg = read_pci_config_16(num, slot, func, cap + 0x14);
 	if (apsizereg == 0xffffffff) {
 		printk(KERN_ERR "APSIZE in AGP bridge unreadable\n");
 		return 0;
 	}

 	apsize = apsizereg & 0xfff;
 	/* Some BIOS use weird encodings not in the AGPv3 table. */
 	if (apsize & 0xff)
 		apsize |= 0xf00;
 	nbits = hweight16(apsize);
 	*order = 7 - nbits;
 	if ((int)*order < 0) /* < 32MB */
 		*order = 0;

 	aper_low = read_pci_config(num, slot, func, 0x10);
 	aper_hi = read_pci_config(num, slot, func, 0x14);
 	aper = (aper_low & ~((1<<22)-1)) | ((u64)aper_hi << 32);

 	printk(KERN_INFO "Aperture from AGP @ %Lx size %u MB (APSIZE %x)\n",
 			aper, 32 << *order, apsizereg);

 	if (!aperture_valid(aper, (32*1024*1024) << *order))
 		return 0;
 	return (u32)aper;
 }

 /*
  * Look for an AGP bridge. Windows only expects the aperture in the
  * AGP bridge and some BIOS forget to initialize the Northbridge too.
  * Work around this here.
  *
  * Do an PCI bus scan by hand because we're running before the PCI
  * subsystem.
  *
  * All K8 AGP bridges are AGPv3 compliant, so we can do this scan
  * generically. It's probably overkill to always scan all slots because
  * the AGP bridges should be always an own bus on the HT hierarchy,
  * but do it here for future safety.
  */
 static __u32 __init search_agp_bridge(u32 *order, int *valid_agp)
 {
 	int num, slot, func;

 	/* Poor man's PCI discovery */
 	for (num = 0; num < 256; num++) {
 		for (slot = 0; slot < 32; slot++) {
 			for (func = 0; func < 8; func++) {
 				u32 class, cap;
 				u8 type;
 				class = read_pci_config(num, slot, func,
 							PCI_CLASS_REVISION);
 				if (class == 0xffffffff)
 					break;

 				switch (class >> 16) {
 				case PCI_CLASS_BRIDGE_HOST:
 				case PCI_CLASS_BRIDGE_OTHER: /* needed? */
 					/* AGP bridge? */
 					cap = find_cap(num, slot, func,
 							PCI_CAP_ID_AGP);
 					if (!cap)
 						break;
 					*valid_agp = 1;
 					return read_agp(num, slot, func, cap,
 							order);
 				}

 				/* No multi-function device? */
 				type = read_pci_config_byte(num, slot, func,
 							       PCI_HEADER_TYPE);
 				if (!(type & 0x80))
 					break;
 			}
 		}
 	}
 	printk(KERN_INFO "No AGP bridge found\n");

 	return 0;
 }

 static int gart_fix_e820 __initdata = 1;

 static int __init parse_gart_mem(char *p)
 {
 	if (!p)
 		return -EINVAL;

 	if (!strncmp(p, "off", 3))
 		gart_fix_e820 = 0;
 	else if (!strncmp(p, "on", 2))
 		gart_fix_e820 = 1;

 	return 0;
 }
 early_param("gart_fix_e820", parse_gart_mem);

 void __init early_gart_iommu_check(void)
 {
 	/*
 	 * in case it is enabled before, esp for kexec/kdump,
 	 * previous kernel already enable that. memset called
 	 * by allocate_aperture/__alloc_bootmem_nopanic cause restart.
 	 * or second kernel have different position for GART hole. and new
 	 * kernel could use hole as RAM that is still used by GART set by
 	 * first kernel
 	 * or BIOS forget to put that in reserved.
 	 * try to update e820 to make that region as reserved.
 	 */
 	int fix, num;
 	u32 ctl;
 	u32 aper_size = 0, aper_order = 0, last_aper_order = 0;
 	u64 aper_base = 0, last_aper_base = 0;
 	int aper_enabled = 0, last_aper_enabled = 0;

 	if (!early_pci_allowed())
 		return;

 	fix = 0;
 	for (num = 24; num < 32; num++) {
 		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 			continue;

 		ctl = read_pci_config(0, num, 3, 0x90);
 		aper_enabled = ctl & 1;
 		aper_order = (ctl >> 1) & 7;
 		aper_size = (32 * 1024 * 1024) << aper_order;
 		aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff;
 		aper_base <<= 25;

 		if ((last_aper_order && aper_order != last_aper_order) ||
 		    (last_aper_base && aper_base != last_aper_base) ||
 		    (last_aper_enabled && aper_enabled != last_aper_enabled)) {
 			fix = 1;
 			break;
 		}
 		last_aper_order = aper_order;
 		last_aper_base = aper_base;
 		last_aper_enabled = aper_enabled;
 	}

 	if (!fix && !aper_enabled)
 		return;

 	if (!aper_base || !aper_size || aper_base + aper_size > 0x100000000UL)
 		fix = 1;

 	if (gart_fix_e820 && !fix && aper_enabled) {
 		if (e820_any_mapped(aper_base, aper_base + aper_size,
 				    E820_RAM)) {
 			/* reserved it, so we can resuse it in second kernel */
 			printk(KERN_INFO "update e820 for GART\n");
 			add_memory_region(aper_base, aper_size, E820_RESERVED);
 			update_e820();
 		}
 		return;
 	}

 	/* different nodes have different setting, disable them all at first*/
 	for (num = 24; num < 32; num++) {
 		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 			continue;

 		ctl = read_pci_config(0, num, 3, 0x90);
 		ctl &= ~1;
 		write_pci_config(0, num, 3, 0x90, ctl);
 	}

 }

 void __init gart_iommu_hole_init(void)
 {
 	u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
 	u64 aper_base, last_aper_base = 0;
 	int fix, num, valid_agp = 0;
 	int node;

 	if (gart_iommu_aperture_disabled || !fix_aperture ||
 	    !early_pci_allowed())
 		return;

 	printk(KERN_INFO  "Checking aperture...\n");

 	fix = 0;
 	node = 0;
 	for (num = 24; num < 32; num++) {
 		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 			continue;

 		iommu_detected = 1;
 		gart_iommu_aperture = 1;

 		aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7;
 		aper_size = (32 * 1024 * 1024) << aper_order;
 		aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff;
 		aper_base <<= 25;

 		printk(KERN_INFO "Node %d: aperture @ %Lx size %u MB\n",
 				node, aper_base, aper_size >> 20);
 		node++;

 		if (!aperture_valid(aper_base, aper_size)) {
 			fix = 1;
 			break;
 		}

 		if ((last_aper_order && aper_order != last_aper_order) ||
 		    (last_aper_base && aper_base != last_aper_base)) {
 			fix = 1;
 			break;
 		}
 		last_aper_order = aper_order;
 		last_aper_base = aper_base;
 	}

 	if (!fix && !fallback_aper_force) {
 		if (last_aper_base) {
 			unsigned long n = (32 * 1024 * 1024) << last_aper_order;

 			insert_aperture_resource((u32)last_aper_base, n);
 		}
 		return;
 	}

 	if (!fallback_aper_force)
 		aper_alloc = search_agp_bridge(&aper_order, &valid_agp);

 	if (aper_alloc) {
 		/* Got the aperture from the AGP bridge */
 	} else if (swiotlb && !valid_agp) {
 		/* Do nothing */
 	} else if ((!no_iommu && end_pfn > MAX_DMA32_PFN) ||
 		   force_iommu ||
 		   valid_agp ||
 		   fallback_aper_force) {
 		printk(KERN_ERR
 			"Your BIOS doesn't leave a aperture memory hole\n");
 		printk(KERN_ERR
 			"Please enable the IOMMU option in the BIOS setup\n");
 		printk(KERN_ERR
 			"This costs you %d MB of RAM\n",
 				32 << fallback_aper_order);

 		aper_order = fallback_aper_order;
 		aper_alloc = allocate_aperture();
 		if (!aper_alloc) {
 			/*
 			 * Could disable AGP and IOMMU here, but it's
 			 * probably not worth it. But the later users
 			 * cannot deal with bad apertures and turning
 			 * on the aperture over memory causes very
 			 * strange problems, so it's better to panic
 			 * early.
 			 */
 			panic("Not enough memory for aperture");
 		}
 	} else {
 		return;
 	}

 	/* Fix up the north bridges */
 	for (num = 24; num < 32; num++) {
 		if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
 			continue;

 		/*
 		 * Don't enable translation yet. That is done later.
 		 * Assume this BIOS didn't initialise the GART so
 		 * just overwrite all previous bits
 		 */
 		write_pci_config(0, num, 3, 0x90, aper_order<<1);
 		write_pci_config(0, num, 3, 0x94, aper_alloc>>25);
 	}
 }
	/*
	* Firmware replacement code.
	*
	* Work around broken BIOSes that don't set an aperture or only set the
	* aperture in the AGP bridge.
	* If all fails map the aperture over some low memory. This is cheaper than
	* doing bounce buffering. The memory is lost. This is done at early boot
	* because only the bootmem allocator can allocate 32+MB.
	*
	* Copyright 2002 Andi Kleen, SuSE Labs.
	*/
	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/init.h>
	#include <linux/bootmem.h>
	#include <linux/mmzone.h>
	#include <linux/pci_ids.h>
	#include <linux/pci.h>
	#include <linux/bitops.h>
	#include <linux/ioport.h>
	#include <linux/suspend.h>
	#include <asm/e820.h>
	#include <asm/io.h>
	#include <asm/gart.h>
	#include <asm/pci-direct.h>
	#include <asm/dma.h>
	#include <asm/k8.h>

	int gart_iommu_aperture;
	int gart_iommu_aperture_disabled __initdata;
	int gart_iommu_aperture_allowed __initdata;

	int fallback_aper_order __initdata = 1; /* 64MB */
	int fallback_aper_force __initdata;

	int fix_aperture __initdata = 1;

	static struct resource gart_resource = {
	.name = "GART",
	.flags = IORESOURCE_MEM,
	};

	static void __init insert_aperture_resource(u32 aper_base, u32 aper_size)
	{
	gart_resource.start = aper_base;
	gart_resource.end = aper_base + aper_size - 1;
	insert_resource(&iomem_resource, &gart_resource);
	}

	/* This code runs before the PCI subsystem is initialized, so just
	access the northbridge directly. */

	static u32 __init allocate_aperture(void)
	{
	u32 aper_size;
	void *p;

	if (fallback_aper_order > 7)
	fallback_aper_order = 7;
	aper_size = (32 * 1024 * 1024) << fallback_aper_order;

	/*
	* Aperture has to be naturally aligned. This means a 2GB aperture
	* won't have much chance of finding a place in the lower 4GB of
	* memory. Unfortunately we cannot move it up because that would
	* make the IOMMU useless.
	*/
	p = __alloc_bootmem_nopanic(aper_size, aper_size, 0);
	if (!p \|\| __pa(p)+aper_size > 0xffffffff) {
	printk(KERN_ERR
	"Cannot allocate aperture memory hole (%p,%uK)\n",
	p, aper_size>>10);
	if (p)
	free_bootmem(__pa(p), aper_size);
	return 0;
	}
	printk(KERN_INFO "Mapping aperture over %d KB of RAM @ %lx\n",
	aper_size >> 10, __pa(p));
	insert_aperture_resource((u32)__pa(p), aper_size);
	register_nosave_region((u32)__pa(p) >> PAGE_SHIFT,
	(u32)__pa(p+aper_size) >> PAGE_SHIFT);

	return (u32)__pa(p);
	}

	static int __init aperture_valid(u64 aper_base, u32 aper_size)
	{
	if (!aper_base)
	return 0;

	if (aper_base + aper_size > 0x100000000UL) {
	printk(KERN_ERR "Aperture beyond 4GB. Ignoring.\n");
	return 0;
	}
	if (e820_any_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
	printk(KERN_ERR "Aperture pointing to e820 RAM. Ignoring.\n");
	return 0;
	}
	if (aper_size < 6410241024) {
	printk(KERN_ERR "Aperture too small (%d MB)\n", aper_size>>20);
	return 0;
	}

	return 1;
	}

	/* Find a PCI capability */
	static __u32 __init find_cap(int num, int slot, int func, int cap)
	{
	int bytes;
	u8 pos;

	if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
	PCI_STATUS_CAP_LIST))
	return 0;

	pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
	for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
	u8 id;

	pos &= ~3;
	id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
	if (id == 0xff)
	break;
	if (id == cap)
	return pos;
	pos = read_pci_config_byte(num, slot, func,
	pos+PCI_CAP_LIST_NEXT);
	}
	return 0;
	}

	/* Read a standard AGPv3 bridge header */
	static __u32 __init read_agp(int num, int slot, int func, int cap, u32 *order)
	{
	u32 apsize;
	u32 apsizereg;
	int nbits;
	u32 aper_low, aper_hi;
	u64 aper;

	printk(KERN_INFO "AGP bridge at %02x:%02x:%02x\n", num, slot, func);
	apsizereg = read_pci_config_16(num, slot, func, cap + 0x14);
	if (apsizereg == 0xffffffff) {
	printk(KERN_ERR "APSIZE in AGP bridge unreadable\n");
	return 0;
	}

	apsize = apsizereg & 0xfff;
	/* Some BIOS use weird encodings not in the AGPv3 table. */
	if (apsize & 0xff)
	apsize \|= 0xf00;
	nbits = hweight16(apsize);
	*order = 7 - nbits;
	if ((int)order < 0) / < 32MB */
	*order = 0;

	aper_low = read_pci_config(num, slot, func, 0x10);
	aper_hi = read_pci_config(num, slot, func, 0x14);
	aper = (aper_low & ~((1<<22)-1)) \| ((u64)aper_hi << 32);

	printk(KERN_INFO "Aperture from AGP @ %Lx size %u MB (APSIZE %x)\n",
	aper, 32 << *order, apsizereg);

	if (!aperture_valid(aper, (3210241024) << *order))
	return 0;
	return (u32)aper;
	}

	/*
	* Look for an AGP bridge. Windows only expects the aperture in the
	* AGP bridge and some BIOS forget to initialize the Northbridge too.
	* Work around this here.
	*
	* Do an PCI bus scan by hand because we're running before the PCI
	* subsystem.
	*
	* All K8 AGP bridges are AGPv3 compliant, so we can do this scan
	* generically. It's probably overkill to always scan all slots because
	* the AGP bridges should be always an own bus on the HT hierarchy,
	* but do it here for future safety.
	*/
	static __u32 __init search_agp_bridge(u32 order, int valid_agp)
	{
	int num, slot, func;

	/* Poor man's PCI discovery */
	for (num = 0; num < 256; num++) {
	for (slot = 0; slot < 32; slot++) {
	for (func = 0; func < 8; func++) {
	u32 class, cap;
	u8 type;
	class = read_pci_config(num, slot, func,
	PCI_CLASS_REVISION);
	if (class == 0xffffffff)
	break;

	switch (class >> 16) {
	case PCI_CLASS_BRIDGE_HOST:
	case PCI_CLASS_BRIDGE_OTHER: /* needed? */
	/* AGP bridge? */
	cap = find_cap(num, slot, func,
	PCI_CAP_ID_AGP);
	if (!cap)
	break;
	*valid_agp = 1;
	return read_agp(num, slot, func, cap,
	order);
	}

	/* No multi-function device? */
	type = read_pci_config_byte(num, slot, func,
	PCI_HEADER_TYPE);
	if (!(type & 0x80))
	break;
	}
	}
	}
	printk(KERN_INFO "No AGP bridge found\n");

	return 0;
	}

	static int gart_fix_e820 __initdata = 1;

	static int __init parse_gart_mem(char *p)
	{
	if (!p)
	return -EINVAL;

	if (!strncmp(p, "off", 3))
	gart_fix_e820 = 0;
	else if (!strncmp(p, "on", 2))
	gart_fix_e820 = 1;

	return 0;
	}
	early_param("gart_fix_e820", parse_gart_mem);

	void __init early_gart_iommu_check(void)
	{
	/*
	* in case it is enabled before, esp for kexec/kdump,
	* previous kernel already enable that. memset called
	* by allocate_aperture/__alloc_bootmem_nopanic cause restart.
	* or second kernel have different position for GART hole. and new
	* kernel could use hole as RAM that is still used by GART set by
	* first kernel
	* or BIOS forget to put that in reserved.
	* try to update e820 to make that region as reserved.
	*/
	int fix, num;
	u32 ctl;
	u32 aper_size = 0, aper_order = 0, last_aper_order = 0;
	u64 aper_base = 0, last_aper_base = 0;
	int aper_enabled = 0, last_aper_enabled = 0;

	if (!early_pci_allowed())
	return;

	fix = 0;
	for (num = 24; num < 32; num++) {
	if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
	continue;

	ctl = read_pci_config(0, num, 3, 0x90);
	aper_enabled = ctl & 1;
	aper_order = (ctl >> 1) & 7;
	aper_size = (32 * 1024 * 1024) << aper_order;
	aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff;
	aper_base <<= 25;

	if ((last_aper_order && aper_order != last_aper_order) \|\|
	(last_aper_base && aper_base != last_aper_base) \|\|
	(last_aper_enabled && aper_enabled != last_aper_enabled)) {
	fix = 1;
	break;
	}
	last_aper_order = aper_order;
	last_aper_base = aper_base;
	last_aper_enabled = aper_enabled;
	}

	if (!fix && !aper_enabled)
	return;

	if (!aper_base \|\| !aper_size \|\| aper_base + aper_size > 0x100000000UL)
	fix = 1;

	if (gart_fix_e820 && !fix && aper_enabled) {
	if (e820_any_mapped(aper_base, aper_base + aper_size,
	E820_RAM)) {
	/* reserved it, so we can resuse it in second kernel */
	printk(KERN_INFO "update e820 for GART\n");
	add_memory_region(aper_base, aper_size, E820_RESERVED);
	update_e820();
	}
	return;
	}

	/* different nodes have different setting, disable them all at first*/
	for (num = 24; num < 32; num++) {
	if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
	continue;

	ctl = read_pci_config(0, num, 3, 0x90);
	ctl &= ~1;
	write_pci_config(0, num, 3, 0x90, ctl);
	}

	}

	void __init gart_iommu_hole_init(void)
	{
	u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
	u64 aper_base, last_aper_base = 0;
	int fix, num, valid_agp = 0;
	int node;

	if (gart_iommu_aperture_disabled \|\| !fix_aperture \|\|
	!early_pci_allowed())
	return;

	printk(KERN_INFO "Checking aperture...\n");

	fix = 0;
	node = 0;
	for (num = 24; num < 32; num++) {
	if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
	continue;

	iommu_detected = 1;
	gart_iommu_aperture = 1;

	aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7;
	aper_size = (32 * 1024 * 1024) << aper_order;
	aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff;
	aper_base <<= 25;

	printk(KERN_INFO "Node %d: aperture @ %Lx size %u MB\n",
	node, aper_base, aper_size >> 20);
	node++;

	if (!aperture_valid(aper_base, aper_size)) {
	fix = 1;
	break;
	}

	if ((last_aper_order && aper_order != last_aper_order) \|\|
	(last_aper_base && aper_base != last_aper_base)) {
	fix = 1;
	break;
	}
	last_aper_order = aper_order;
	last_aper_base = aper_base;
	}

	if (!fix && !fallback_aper_force) {
	if (last_aper_base) {
	unsigned long n = (32 * 1024 * 1024) << last_aper_order;

	insert_aperture_resource((u32)last_aper_base, n);
	}
	return;
	}

	if (!fallback_aper_force)
	aper_alloc = search_agp_bridge(&aper_order, &valid_agp);

	if (aper_alloc) {
	/* Got the aperture from the AGP bridge */
	} else if (swiotlb && !valid_agp) {
	/* Do nothing */
	} else if ((!no_iommu && end_pfn > MAX_DMA32_PFN) \|\|
	force_iommu \|\|
	valid_agp \|\|
	fallback_aper_force) {
	printk(KERN_ERR
	"Your BIOS doesn't leave a aperture memory hole\n");
	printk(KERN_ERR
	"Please enable the IOMMU option in the BIOS setup\n");
	printk(KERN_ERR
	"This costs you %d MB of RAM\n",
	32 << fallback_aper_order);

	aper_order = fallback_aper_order;
	aper_alloc = allocate_aperture();
	if (!aper_alloc) {
	/*
	* Could disable AGP and IOMMU here, but it's
	* probably not worth it. But the later users
	* cannot deal with bad apertures and turning
	* on the aperture over memory causes very
	* strange problems, so it's better to panic
	* early.
	*/
	panic("Not enough memory for aperture");
	}
	} else {
	return;
	}

	/* Fix up the north bridges */
	for (num = 24; num < 32; num++) {
	if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
	continue;

	/*
	* Don't enable translation yet. That is done later.
	* Assume this BIOS didn't initialise the GART so
	* just overwrite all previous bits
	*/
	write_pci_config(0, num, 3, 0x90, aper_order<<1);
	write_pci_config(0, num, 3, 0x94, aper_alloc>>25);
	}
	}