[PATCH] Calgary: allow compiling Calgary in but not using it by default
This patch makes it possible to compile Calgary in but not use it by
default. In this mode, use 'iommu=calgary' to activate it.
Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 010d226..5cb509d 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -455,6 +455,17 @@
Normally the kernel will make the right choice by itself.
If unsure, say Y.
+config CALGARY_IOMMU_ENABLED_BY_DEFAULT
+ bool "Should Calgary be enabled by default?"
+ default y
+ depends on CALGARY_IOMMU
+ help
+ Should Calgary be enabled by default? if you choose 'y', Calgary
+ will be used (if it exists). If you choose 'n', Calgary will not be
+ used even if it exists. If you choose 'n' and would like to use
+ Calgary anyway, pass 'iommu=calgary' on the kernel command line.
+ If unsure, say Y.
+
# need this always selected by IOMMU for the VIA workaround
config SWIOTLB
bool
diff --git a/arch/x86_64/kernel/pci-calgary.c b/arch/x86_64/kernel/pci-calgary.c
index 8a1e4f3..0ddf29d 100644
--- a/arch/x86_64/kernel/pci-calgary.c
+++ b/arch/x86_64/kernel/pci-calgary.c
@@ -43,6 +43,12 @@
#include <asm/dma.h>
#include <asm/rio.h>
+#ifdef CONFIG_CALGARY_IOMMU_ENABLED_BY_DEFAULT
+int use_calgary __read_mostly = 1;
+#else
+int use_calgary __read_mostly = 0;
+#endif /* CONFIG_CALGARY_DEFAULT_ENABLED */
+
#define PCI_DEVICE_ID_IBM_CALGARY 0x02a1
#define PCI_VENDOR_DEVICE_ID_CALGARY \
(PCI_VENDOR_ID_IBM | PCI_DEVICE_ID_IBM_CALGARY << 16)
@@ -1061,6 +1067,9 @@
if (swiotlb || no_iommu || iommu_detected)
return;
+ if (!use_calgary)
+ return;
+
if (!early_pci_allowed())
return;
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index f8d8574..683b7a5 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -296,6 +296,11 @@
gart_parse_options(p);
#endif
+#ifdef CONFIG_CALGARY_IOMMU
+ if (!strncmp(p, "calgary", 7))
+ use_calgary = 1;
+#endif /* CONFIG_CALGARY_IOMMU */
+
p += strcspn(p, ",");
if (*p == ',')
++p;