1 files changed, 286 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/aperture.c b/arch/x86_64/kernel/aperture.c
new file mode 100644
index 000000000000..4baa99fe1e5c
--- /dev/null
+++ b/arch/x86_64/kernel/aperture.c
@@ -0,0 +1,286 @@
+/* 
+ * 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.
+ * $Id: aperture.c,v 1.7 2003/08/01 03:36:18 ak Exp $
+ */
+#include <linux/config.h>
+#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 <asm/e820.h>
+#include <asm/io.h>
+#include <asm/proto.h>
+#include <asm/pci-direct.h>
+
+int iommu_aperture;
+int iommu_aperture_disabled __initdata = 0;
+int iommu_aperture_allowed __initdata = 0;
+
+int fallback_aper_order __initdata = 1; /* 64MB */
+int fallback_aper_force __initdata = 0; 
+
+int fix_aperture __initdata = 1;
+
+/* This code runs before the PCI subsystem is initialized, so just 
+   access the northbridge directly. */
+
+#define NB_ID_3 (PCI_VENDOR_ID_AMD | (0x1103<<16))
+
+static u32 __init allocate_aperture(void) 
+{
+#ifdef CONFIG_DISCONTIGMEM
+	pg_data_t *nd0 = NODE_DATA(0);
+#else
+	pg_data_t *nd0 = &contig_page_data;
+#endif	
+	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 an 2GB aperture won't 
+	 * have much chances to find a place in the lower 4GB of memory. 
+	 * Unfortunately we cannot move it up because that would make the 
+	 * IOMMU useless.
+	 */
+	p = __alloc_bootmem_node(nd0, aper_size, aper_size, 0); 
+	if (!p || __pa(p)+aper_size > 0xffffffff) {
+		printk("Cannot allocate aperture memory hole (%p,%uK)\n",
+		       p, aper_size>>10);
+		if (p)
+			free_bootmem_node(nd0, (unsigned long)p, aper_size); 
+		return 0;
+	}
+	printk("Mapping aperture over %d KB of RAM @ %lx\n",  
+	       aper_size >> 10, __pa(p)); 
+	return (u32)__pa(p); 
+}
+
+static int __init aperture_valid(char *name, u64 aper_base, u32 aper_size) 
+{ 
+	if (!aper_base) 
+		return 0;
+	if (aper_size < 64*1024*1024) { 
+		printk("Aperture from %s too small (%d MB)\n", name, aper_size>>20); 
+		return 0;
+	}
+	if (aper_base + aper_size >= 0xffffffff) { 
+		printk("Aperture from %s beyond 4GB. Ignoring.\n",name);
+		return 0; 
+	}
+	if (e820_mapped(aper_base, aper_base + aper_size, E820_RAM)) {  
+		printk("Aperture from %s pointing to e820 RAM. Ignoring.\n",name);
+		return 0; 
+	} 
+	return 1;
+} 
+
+/* Find a PCI capability */ 
+static __u32 __init find_cap(int num, int slot, int func, int cap) 
+{ 
+	u8 pos;
+	int bytes;
+	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("AGP bridge at %02x:%02x:%02x\n", num, slot, func);
+	apsizereg = read_pci_config_16(num,slot,func, cap + 0x14);
+	if (apsizereg == 0xffffffff) {
+		printk("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("Aperture from AGP @ %Lx size %u MB (APSIZE %x)\n", 
+	       aper, 32 << *order, apsizereg);
+
+	if (!aperture_valid("AGP bridge", 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 < 32; 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("No AGP bridge found\n"); 
+	return 0;
+}
+
+void __init iommu_hole_init(void) 
+{ 
+	int fix, num; 
+	u32 aper_size, aper_alloc = 0, aper_order, last_aper_order = 0;
+	u64 aper_base, last_aper_base = 0;
+	int valid_agp = 0;
+
+	if (iommu_aperture_disabled || !fix_aperture)
+		return;
+
+	printk("Checking aperture...\n"); 
+
+	fix = 0;
+	for (num = 24; num < 32; num++) {		
+		char name[30];
+		if (read_pci_config(0, num, 3, 0x00) != NB_ID_3) 
+			continue;	
+
+		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("CPU %d: aperture @ %Lx size %u MB\n", num-24, 
+		       aper_base, aper_size>>20);
+		
+		sprintf(name, "northbridge cpu %d", num-24); 
+
+		if (!aperture_valid(name, 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) 
+		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 ((!no_iommu && end_pfn >= 0xffffffff>>PAGE_SHIFT) ||
+		   force_iommu ||
+		   valid_agp ||
+		   fallback_aper_force) { 
+		printk("Your BIOS doesn't leave a aperture memory hole\n");
+		printk("Please enable the IOMMU option in the BIOS setup\n");
+		printk("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 (read_pci_config(0, num, 3, 0x00) != NB_ID_3) 
+			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); 
+	} 
+}