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Diffstat (limited to 'arch/x86/kernel/aperture_64.c')
-rw-r--r--arch/x86/kernel/aperture_64.c298
1 files changed, 298 insertions, 0 deletions
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
new file mode 100644
index 000000000000..8f681cae7bf7
--- /dev/null
+++ b/arch/x86/kernel/aperture_64.c
@@ -0,0 +1,298 @@
+/*
+ * 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 <asm/e820.h>
+#include <asm/io.h>
+#include <asm/iommu.h>
+#include <asm/pci-direct.h>
+#include <asm/dma.h>
+#include <asm/k8.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;
+
+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 an 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("Cannot allocate aperture memory hole (%p,%uK)\n",
+ p, aper_size>>10);
+ if (p)
+ free_bootmem(__pa(p), aper_size);
+ return 0;
+ }
+ printk("Mapping aperture over %d KB of RAM @ %lx\n",
+ aper_size >> 10, __pa(p));
+ insert_aperture_resource((u32)__pa(p), aper_size);
+ return (u32)__pa(p);
+}
+
+static int __init aperture_valid(u64 aper_base, u32 aper_size)
+{
+ if (!aper_base)
+ return 0;
+ if (aper_size < 64*1024*1024) {
+ printk("Aperture too small (%d MB)\n", aper_size>>20);
+ return 0;
+ }
+ if (aper_base + aper_size > 0x100000000UL) {
+ printk("Aperture beyond 4GB. Ignoring.\n");
+ return 0;
+ }
+ if (e820_any_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
+ printk("Aperture pointing to e820 RAM. Ignoring.\n");
+ 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(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("No AGP bridge found\n");
+ return 0;
+}
+
+void __init iommu_hole_init(void)
+{
+ int fix, num;
+ u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
+ u64 aper_base, last_aper_base = 0;
+ int valid_agp = 0;
+
+ if (iommu_aperture_disabled || !fix_aperture || !early_pci_allowed())
+ return;
+
+ printk(KERN_INFO "Checking aperture...\n");
+
+ fix = 0;
+ for (num = 24; num < 32; num++) {
+ if (!early_is_k8_nb(read_pci_config(0, num, 3, 0x00)))
+ continue;
+
+ iommu_detected = 1;
+ 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);
+
+ 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("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 (!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);
+ }
+}
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