[PATCH 1/4] x86-64: Calgary IOMMU - introduce iommu_detected

Jon Mason
2006-05-25T03:29:57Z

swiotlb relies on the gart specific iommu_aperture variable to know if
we discovered a hardware IOMMU before swiotlb initialization. Introduce
iommu_detected to do the same thing, but in a HW IOMMU neutral manner,
in preparation for adding the Calgary HW IOMMU.

Thanks,
Jon

Signed-Off-By: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-Off-By: Jon Mason <jdmason@us.ibm.com>

diff -r 82f66cc5a33b arch/x86_64/kernel/aperture.c
--- a/arch/x86_64/kernel/aperture.c Tue May 23 18:57:22 2006
+++ b/arch/x86_64/kernel/aperture.c Tue May 23 14:05:16 2006
@@ -212,6 +212,7 @@
if (read_pci_config(0, num, 3, 0x00) != NB_ID_3)
continue;

+ iommu_detected = 1;
iommu_aperture = 1;

aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7;
diff -r 82f66cc5a33b arch/x86_64/kernel/pci-dma.c
--- a/arch/x86_64/kernel/pci-dma.c Tue May 23 18:57:22 2006
+++ b/arch/x86_64/kernel/pci-dma.c Tue May 23 14:05:16 2006
@@ -32,6 +32,9 @@
int panic_on_overflow __read_mostly = 0;
int force_iommu __read_mostly= 0;
#endif
+
+/* Set this to 1 if there is a HW IOMMU in the system */
+int iommu_detected __read_mostly = 0;

/* Dummy device used for NULL arguments (normally ISA). Better would
be probably a smaller DMA mask, but this is bug-to-bug compatible
diff -r 82f66cc5a33b arch/x86_64/kernel/pci-gart.c
--- a/arch/x86_64/kernel/pci-gart.c Tue May 23 18:57:22 2006
+++ b/arch/x86_64/kernel/pci-gart.c Tue May 23 14:05:16 2006
@@ -624,6 +624,10 @@
if (swiotlb)
return -1;

+ /* Did we detect a different HW IOMMU? */
+ if (iommu_detected && !iommu_aperture)
+ return -1;
+
if (no_iommu ||
(!force_iommu && end_pfn <= MAX_DMA32_PFN) ||
!iommu_aperture ||
diff -r 82f66cc5a33b arch/x86_64/kernel/pci-swiotlb.c
--- a/arch/x86_64/kernel/pci-swiotlb.c Tue May 23 18:57:22 2006
+++ b/arch/x86_64/kernel/pci-swiotlb.c Tue May 23 14:05:16 2006
@@ -31,7 +31,7 @@
void pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
- if (!iommu_aperture && !no_iommu &&
+ if (!iommu_detected && !no_iommu &&
(end_pfn > MAX_DMA32_PFN || force_iommu))
swiotlb = 1;
if (swiotlb) {
diff -r 82f66cc5a33b include/asm-x86_64/proto.h
--- a/include/asm-x86_64/proto.h Tue May 23 18:57:22 2006
+++ b/include/asm-x86_64/proto.h Tue May 23 14:05:16 2006
@@ -116,6 +116,7 @@
extern int acpi_ht;
extern int acpi_disabled;

+extern int iommu_detected;
#ifdef CONFIG_GART_IOMMU
extern int fallback_aper_order;
extern int fallback_aper_force;