1 files changed, 38 insertions, 13 deletions

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index af44130f0d65..ccc4a7fb97a3 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -386,24 +386,45 @@ config HPET_EMULATE_RTC
         bool "Provide RTC interrupt"
         depends on HPET_TIMER && RTC=y
 
-config GART_IOMMU
-        bool "K8 GART IOMMU support"
+# Mark as embedded because too many people got it wrong.
+# The code disables itself when not needed.
+config IOMMU
+        bool "IOMMU support" if EMBEDDED
         default y
         select SWIOTLB
         select AGP
         depends on PCI
         help
-          Support for hardware IOMMU in AMD's Opteron/Athlon64 Processors
-          and for the bounce buffering software IOMMU.
-          Needed to run systems with more than 3GB of memory properly with
-          32-bit PCI devices that do not support DAC (Double Address Cycle).
-          The IOMMU can be turned off at runtime with the iommu=off parameter.
-          Normally the kernel will take the right choice by itself.
-          This option includes a driver for the AMD Opteron/Athlon64 IOMMU
-          northbridge and a software emulation used on other systems without
-          hardware IOMMU.  If unsure, say Y.
-
-# need this always selected by GART_IOMMU for the VIA workaround
+          Support for full DMA access of devices with 32bit memory access only
+          on systems with more than 3GB. This is usually needed for USB,
+          sound, many IDE/SATA chipsets and some other devices.
+          Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
+          based IOMMU and a software bounce buffer based IOMMU used on Intel
+          systems and as fallback.
+          The code is only active when needed (enough memory and limited
+          device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
+          too.
+
+config CALGARY_IOMMU
+        bool "IBM Calgary IOMMU support"
+        default y
+        select SWIOTLB
+        depends on PCI && EXPERIMENTAL
+        help
+          Support for hardware IOMMUs in IBM's xSeries x366 and x460
+          systems. Needed to run systems with more than 3GB of memory
+          properly with 32-bit PCI devices that do not support DAC
+          (Double Address Cycle). Calgary also supports bus level
+          isolation, where all DMAs pass through the IOMMU.  This
+          prevents them from going anywhere except their intended
+          destination. This catches hard-to-find kernel bugs and
+          mis-behaving drivers and devices that do not use the DMA-API
+          properly to set up their DMA buffers.  The IOMMU can be
+          turned off at boot time with the iommu=off parameter.
+          Normally the kernel will make the right choice by itself.
+          If unsure, say Y.
+
+# need this always selected by IOMMU for the VIA workaround
 config SWIOTLB
         bool
 
@@ -501,6 +522,10 @@ config REORDER
          optimal TLB usage. If you have pretty much any version of binutils, 
          this can increase your kernel build time by roughly one minute.
 
+config K8_NB
+        def_bool y
+        depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
+
 endmenu
 
 #