patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/aperture.c
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- 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);
+ }
+}
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