/*
* 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/gart.h>
#include <asm/pci-direct.h>
#include <asm/dma.h>
#include <asm/k8.h>
int gart_iommu_aperture;
int gart_iommu_aperture_disabled __initdata = 0;
int gart_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 a 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(KERN_ERR
"Cannot allocate aperture memory hole (%p,%uK)\n",
p, aper_size>>10);
if (p)
free_bootmem(__pa(p), aper_size);
return 0;
}
printk(KERN_INFO "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(KERN_ERR "Aperture too small (%d MB)\n", aper_size>>20);
return 0;
}
if (aper_base + aper_size > 0x100000000UL) {
printk(KERN_ERR "Aperture beyond 4GB. Ignoring.\n");
return 0;
}
if (e820_any_mapped(aper_base, aper_base + aper_size, E820_RAM)) {
printk(KERN_ERR "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)
{
int bytes;
u8 pos;
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(KERN_INFO "AGP bridge at %02x:%02x:%02x\n", num, slot, func);
apsizereg = read_pci_config_16(num, slot, func, cap + 0x14);
if (apsizereg == 0xffffffff) {
printk(KERN_ERR "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(KERN_INFO "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(KERN_INFO "No AGP bridge found\n");
return 0;
}
void __init gart_iommu_hole_init(void)
{
u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
u64 aper_base, last_aper_base = 0;
int fix, num, valid_agp = 0;
if (gart_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;
gart_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(KERN_INFO "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(KERN_ERR
"Your BIOS doesn't leave a aperture memory hole\n");
printk(KERN_ERR
"Please enable the IOMMU option in the BIOS setup\n");
printk(KERN_ERR
"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);
}
}
