[PATCH 1/3] x86-64: Calgary IOMMU - introduce iommu_detected

From: Muli Ben-Yehuda
Date: Mon Mar 20 2006 - 03:46:42 EST


Hi,

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.

This is patch -B2 against 2.6.16, unchanged from previous version.

Signed-Off-By: Muli Ben-Yehuda <mulix@xxxxxxxxx>
Signed-Off-By: Jon Mason <jdmason@xxxxxxxxxx>

diff -Naurp --exclude-from /home/muli/w/dontdiff vanilla/arch/x86_64/kernel/aperture.c iommu_detected/arch/x86_64/kernel/aperture.c
--- vanilla/arch/x86_64/kernel/aperture.c 2006-03-14 08:24:37.000000000 +0200
+++ iommu_detected/arch/x86_64/kernel/aperture.c 2006-03-14 09:05:00.000000000 +0200
@@ -212,6 +212,7 @@ void __init iommu_hole_init(void)
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 -Naurp --exclude-from /home/muli/w/dontdiff vanilla/arch/x86_64/kernel/pci-dma.c iommu_detected/arch/x86_64/kernel/pci-dma.c
--- vanilla/arch/x86_64/kernel/pci-dma.c 2006-03-14 08:24:37.000000000 +0200
+++ iommu_detected/arch/x86_64/kernel/pci-dma.c 2006-03-14 09:05:48.000000000 +0200
@@ -33,6 +33,9 @@ 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
to i386. */
diff -Naurp --exclude-from /home/muli/w/dontdiff vanilla/arch/x86_64/kernel/pci-gart.c iommu_detected/arch/x86_64/kernel/pci-gart.c
--- vanilla/arch/x86_64/kernel/pci-gart.c 2006-03-14 08:24:37.000000000 +0200
+++ iommu_detected/arch/x86_64/kernel/pci-gart.c 2006-03-14 09:06:44.000000000 +0200
@@ -627,6 +627,10 @@ static int __init pci_iommu_init(void)
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 -Naurp --exclude-from /home/muli/w/dontdiff vanilla/arch/x86_64/kernel/pci-swiotlb.c iommu_detected/arch/x86_64/kernel/pci-swiotlb.c
--- vanilla/arch/x86_64/kernel/pci-swiotlb.c 2006-03-14 08:24:37.000000000 +0200
+++ iommu_detected/arch/x86_64/kernel/pci-swiotlb.c 2006-03-14 09:07:05.000000000 +0200
@@ -31,7 +31,7 @@ struct dma_mapping_ops swiotlb_dma_ops =
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 -Naurp --exclude-from /home/muli/w/dontdiff vanilla/include/asm-x86_64/dma-mapping.h iommu_detected/include/asm-x86_64/dma-mapping.h
--- vanilla/include/asm-x86_64/dma-mapping.h 2006-03-14 08:26:27.000000000 +0200
+++ iommu_detected/include/asm-x86_64/dma-mapping.h 2006-03-14 09:07:56.000000000 +0200
@@ -183,5 +183,6 @@ dma_cache_sync(void *vaddr, size_t size,

extern struct device fallback_dev;
extern int panic_on_overflow;
+extern int iommu_detected;

#endif /* _X8664_DMA_MAPPING_H */


--
Muli Ben-Yehuda
http://www.mulix.org | http://mulix.livejournal.com/

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