- 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 enabled with 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