[PATCH] x86_64: Rename IOMMU option, fix help and mark option embedded.

 - Rename the GART_IOMMU option to IOMMU to make clear it's not
   just for AMD
 - Rewrite the help text to better emphatise this fact
 - Make it an embedded option because too many people get it wrong.

To my astonishment I discovered the aacraid driver tests this
symbol directly. This looks quite broken to me - it's an internal
implementation detail of the PCI DMA API. Can the maintainer
please clarify what this test was intended to do?

Cc: linux-scsi@vger.kernel.org
Cc: alan@redhat.com
Cc: markh@osdl.org
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 14 deletions

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index fc75275d8c72..e8c52a1eec06 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -386,24 +386,26 @@ 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.
+
+# need this always selected by IOMMU for the VIA workaround
 config SWIOTLB
         bool
 
@@ -503,7 +505,7 @@ config REORDER
 
 config K8_NB
         def_bool y
-        depends on AGP_AMD64 || GART_IOMMU || (PCI && NUMA)
+        depends on AGP_AMD64 || IOMMU || (PCI && NUMA)
 
 endmenu