[PATCH] x86 GART: Add resume handling (was: Re: >3G => iommu => suspend problems -- was Re: SB600 AHCI: Hard Disk Corruption)

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Monday, 9 of June 2008, Ingo Molnar wrote:
> 
> * Rafael J. Wysocki <rjw@sisk.pl> wrote:
> 
> > > Looks ok to me.
> > 
> > Still, it may be improved. :-)
> > 
> > First, we shouldn't mix the "early PCI config access" thing with the 
> > "normal" method.  Second, we don't have to check for the K8 north 
> > bridges on resume, because we already know where they are in the 
> > configuration space and we can use this information.
> > 
> > Updated patch follows.  It has been tested a little on my new 4 GB 
> > test box on which 2.6.26-rc4 failed miserably with severe 
> > consequences.  More testing welcome, but please be careful.
> 
> Rafael, could we try this against the tip/x86/gart tree perhaps? It 
> already has a couple of fixes from Pavel and your patch collides with 
> them in a non-obvious way.
> 
>   http://people.redhat.com/mingo/tip.git/README

Okay, appended is the patch rebased on tip/x86/gart with (mainline) commit
cd76374e9de4501acc74f833dc6cb5e7a5dca115 "suspend-vs-iommu: prevent suspend if
we could not resume" (which appears to be missing from tip/x86/gart) applied.

This version of the patch doesn't break compilation, but it hasn't been really
tested yet.

Thanks,
Rafael

---
Add resume handling to GART IOMMU.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 arch/x86/kernel/aperture_64.c |    2 +
 arch/x86/kernel/pci-gart_64.c |   57 ++++++++++++++++++++++++++++++++++++++----
 include/asm-x86/gart.h        |    1 
 3 files changed, 55 insertions(+), 5 deletions(-)

Index: tip.git/arch/x86/kernel/aperture_64.c
===================================================================
--- tip.git.orig/arch/x86/kernel/aperture_64.c
+++ tip.git/arch/x86/kernel/aperture_64.c
@@ -496,4 +496,6 @@ out:
 			write_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE, aper_alloc >> 25);
 		}
 	}
+
+	set_up_gart_resume(aper_order, aper_alloc);
 }
Index: tip.git/arch/x86/kernel/pci-gart_64.c
===================================================================
--- tip.git.orig/arch/x86/kernel/pci-gart_64.c
+++ tip.git/arch/x86/kernel/pci-gart_64.c
@@ -549,14 +549,63 @@ static __init unsigned read_aperture(str
 	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 = {
@@ -614,16 +663,14 @@ static __init int init_k8_gatt(struct ag
 	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",
Index: tip.git/include/asm-x86/gart.h
===================================================================
--- tip.git.orig/include/asm-x86/gart.h
+++ tip.git/include/asm-x86/gart.h
@@ -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;