patch-2.4.22 linux-2.4.22/arch/x86_64/kernel/aperture.c
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- Lines: 240
- Date:
2003-08-25 04:44:40.000000000 -0700
- Orig file:
linux-2.4.21/arch/x86_64/kernel/aperture.c
- Orig date:
2003-06-13 07:51:32.000000000 -0700
diff -urN linux-2.4.21/arch/x86_64/kernel/aperture.c linux-2.4.22/arch/x86_64/kernel/aperture.c
@@ -1,14 +1,14 @@
/*
* 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.
+ * 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 1.4 2002/11/28 06:05:58 ak Exp $
+ * $Id: aperture.c,v 1.7 2003/08/01 03:36:18 ak Exp $
*/
#include <linux/config.h>
#include <linux/kernel.h>
@@ -17,6 +17,8 @@
#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>
@@ -64,16 +66,130 @@
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)
+{
+ if (!(read_pci_config_16(num,slot,func,PCI_STATUS) & PCI_STATUS_CAP_LIST))
+ return 0;
+ u8 pos = read_pci_config_byte(num,slot,func,PCI_CAPABILITY_LIST);
+ int bytes;
+ for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
+ pos &= ~3;
+ u8 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)
+{
+ printk("AGP bridge at %02x:%02x:%02x\n", num, slot, func);
+ u32 apsizereg = read_pci_config_16(num,slot,func, cap + 0x14);
+
+ if (apsizereg == 0xffffffff) {
+ printk("APSIZE in AGP bridge unreadable\n");
+ return 0;
+ }
+
+ u32 apsize = apsizereg & 0xfff;
+ /* Some BIOS use weird encodings not in the AGPv3 table. */
+ if (apsize & 0xff)
+ apsize |= 0xf00;
+ int nbits = hweight16(apsize);
+ *order = 7 - nbits;
+ if ((int)*order < 0) /* < 32MB */
+ *order = 0;
+
+ u32 aper_low = read_pci_config(num,slot,func, 0x10);
+ u32 aper_hi = read_pci_config(num,slot,func,0x14);
+ u64 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;
+ 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? */
+ u8 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, aper_order;
+ u32 aper_size, aper_alloc = 0, aper_order;
u64 aper_base;
-
- if (no_iommu)
- return;
- if (end_pfn < (0xffffffff>>PAGE_SHIFT) && !force_mmu)
- return;
+ int valid_agp = 0;
printk("Checking aperture...\n");
@@ -87,15 +203,13 @@
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;
- }
+ printk("CPU %d: aperture @ %Lx size %u MB\n", num-24,
+ aper_base, aper_size>>20);
- if (e820_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
- printk("Aperture pointing to e820 RAM. Ignoring.\n");
+ char name[30];
+ sprintf(name, "northbridge cpu %d", num-24);
+
+ if (!aperture_valid(name, aper_base, aper_size)) {
fix = 1;
break;
}
@@ -104,12 +218,40 @@
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_mmu ||
+ valid_agp ||
+ fallback_aper_force) {
+ /* When there is a AGP bridge in the system assume the
+ user wants to use the AGP driver too and needs an
+ aperture. However this case (AGP but no good
+ aperture) should only happen with a more broken than
+ usual BIOS, because it would even break Windows. */
+
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)
+ 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;
@@ -117,7 +259,7 @@
/* 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, 0x90, aper_order<<1);
write_pci_config(0, num, 3, 0x94, aper_alloc>>25);
}
}
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