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x86, gart: add resume handling
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If GART IOMMU is used on an AMD64 system, the northbridge registers
related to it should be restored during resume so that memory is not
corrupted.  Make gart_resume() handle that as appropriate.

Ref. http://lkml.org/lkml/2008/5/25/96 and the following thread.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Rafael J. Wysocki authored and Ingo Molnar committed Jun 12, 2008
1 parent bb6dfb3 commit 6703f6d
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Showing 3 changed files with 55 additions and 5 deletions.
2 changes: 2 additions & 0 deletions arch/x86/kernel/aperture_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -496,4 +496,6 @@ void __init gart_iommu_hole_init(void)
write_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE, aper_alloc >> 25);
}
}

set_up_gart_resume(aper_order, aper_alloc);
}
57 changes: 52 additions & 5 deletions arch/x86/kernel/pci-gart_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -549,14 +549,63 @@ static __init unsigned read_aperture(struct pci_dev *dev, u32 *size)
return aper_base;
}

static void enable_gart_translations(void)
{
int i;

for (i = 0; i < num_k8_northbridges; i++) {
struct pci_dev *dev = k8_northbridges[i];

enable_gart_translation(dev, __pa(agp_gatt_table));
}
}

/*
* If fix_up_north_bridges is set, the north bridges have to be fixed up on
* resume in the same way as they are handled in gart_iommu_hole_init().
*/
static bool fix_up_north_bridges;
static u32 aperture_order;
static u32 aperture_alloc;

void set_up_gart_resume(u32 aper_order, u32 aper_alloc)
{
fix_up_north_bridges = true;
aperture_order = aper_order;
aperture_alloc = aper_alloc;
}

static int gart_resume(struct sys_device *dev)
{
printk(KERN_INFO "PCI-DMA: Resuming GART IOMMU\n");

if (fix_up_north_bridges) {
int i;

printk(KERN_INFO "PCI-DMA: Restoring GART aperture settings\n");

for (i = 0; i < num_k8_northbridges; i++) {
struct pci_dev *dev = k8_northbridges[i];

/*
* Don't enable translations just yet. That is the next
* step. Restore the pre-suspend aperture settings.
*/
pci_write_config_dword(dev, AMD64_GARTAPERTURECTL,
aperture_order << 1);
pci_write_config_dword(dev, AMD64_GARTAPERTUREBASE,
aperture_alloc >> 25);
}
}

enable_gart_translations();

return 0;
}

static int gart_suspend(struct sys_device *dev, pm_message_t state)
{
return -EINVAL;
return 0;
}

static struct sysdev_class gart_sysdev_class = {
Expand Down Expand Up @@ -614,16 +663,14 @@ static __init int init_k8_gatt(struct agp_kern_info *info)
memset(gatt, 0, gatt_size);
agp_gatt_table = gatt;

for (i = 0; i < num_k8_northbridges; i++) {
dev = k8_northbridges[i];
enable_gart_translation(dev, __pa(gatt));
}
enable_gart_translations();

error = sysdev_class_register(&gart_sysdev_class);
if (!error)
error = sysdev_register(&device_gart);
if (error)
panic("Could not register gart_sysdev -- would corrupt data on next suspend");

flush_gart();

printk(KERN_INFO "PCI-DMA: aperture base @ %x size %u KB\n",
Expand Down
1 change: 1 addition & 0 deletions include/asm-x86/gart.h
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ extern void gart_iommu_shutdown(void);
extern void __init gart_parse_options(char *);
extern void early_gart_iommu_check(void);
extern void gart_iommu_hole_init(void);
extern void set_up_gart_resume(u32, u32);
extern int fallback_aper_order;
extern int fallback_aper_force;
extern int gart_iommu_aperture;
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