patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/aperture.c

• Lines: 124
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/kernel/aperture.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/kernel/aperture.c linux-2.4.20/arch/x86_64/kernel/aperture.c
@@ -0,0 +1,123 @@
+/* 
+ * Firmware replacement code.
+ * 
+ * Work around broken BIOSes that don't set an aperture. 
+ * The IOMMU code needs an aperture even who no AGP is present in the system.
+ * 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 1.2 2002/09/19 19:25:32 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 <asm/e820.h>
+#include <asm/io.h>
+#include <asm/proto.h>
+#include <asm/pci-direct.h>
+
+int fallback_aper_order __initdata = 1; /* 64MB */
+int fallback_aper_force __initdata = 0; 
+
+extern int no_iommu, force_mmu;
+
+/* 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 it seems. This means an
+	 * 2GB aperture won't have much changes to succeed 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_generic((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); 
+}
+
+void __init iommu_hole_init(void) 
+{ 
+	int fix, num; 
+	u32 aper_size, aper_alloc, aper_order;
+	u64 aper_base; 
+
+	if (no_iommu)
+		return;
+	if (end_pfn < (0xffffffff>>PAGE_SHIFT) && !force_mmu) 
+		return;
+
+	printk("Checking aperture...\n"); 
+
+	fix = 0;
+	for (num = 24; num < 32; num++) {		
+		if (read_pci_config(0, num, 3, 0x00) != NB_ID_3) 
+			continue;	
+
+		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 KB\n", num-24, 
+		       aper_base, aper_size>>10);
+		if (!aper_base || aper_base + aper_size >= 0xffffffff) {
+			fix = 1; 
+			break; 
+		} 
+		
+		if (e820_mapped(aper_base, aper_base + aper_size, E820_RAM)) {  
+			printk("Aperture pointing to e820 RAM. Ignoring.\n");
+			fix = 1; 
+			break; 
+		} 
+	} 
+
+	if (!fix && !fallback_aper_force) 
+		return; 
+
+	printk("Your BIOS is broken and doesn't leave a aperture memory hole\n");
+	aper_alloc = allocate_aperture(); 
+	if (!aper_alloc) 
+		return; 
+
+	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, fallback_aper_order<<1); 
+		write_pci_config(0, num, 3, 0x94, aper_alloc>>25); 
+	} 
+}