[PATCH] x86_64: Calgary IOMMU - Calgary specific bits

This patch hooks Calgary into the build, the x86-64 IOMMU
initialization paths, and introduces the Calgary specific bits.  The
implementation draws inspiration from both PPC (which has support for
the same chip but requires firmware support which we don't have on
x86-64) and gart. Calgary is different from gart in that it support a
translation table per PHB, as opposed to the single gart aperture.

Changes from previous version:
 * Addition of boot-time disablement for bus-level translation/isolation
   (e.g, enable userspace DMA for things like X)
 * Usage of newer IOMMU abstraction functions

Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/x86_64/boot-options.txt

@@ -205,6 +205,27 @@ IOMMU
   pages  Prereserve that many 128K pages for the software IO bounce buffering.
   force  Force all IO through the software TLB.
 
+  calgary=[64k,128k,256k,512k,1M,2M,4M,8M]
+  calgary=[translate_empty_slots]
+  calgary=[disable=<PCI bus number>]
+
+    64k,...,8M - Set the size of each PCI slot's translation table
+    when using the Calgary IOMMU. This is the size of the translation
+    table itself in main memory. The smallest table, 64k, covers an IO
+    space of 32MB; the largest, 8MB table, can cover an IO space of
+    4GB. Normally the kernel will make the right choice by itself.
+
+    translate_empty_slots - Enable translation even on slots that have
+    no devices attached to them, in case a device will be hotplugged
+    in the future.
+
+    disable=<PCI bus number> - Disable translation on a given PHB. For
+    example, the built-in graphics adapter resides on the first bridge
+    (PCI bus number 0); if translation (isolation) is enabled on this
+    bridge, X servers that access the hardware directly from user
+    space might stop working. Use this option if you have devices that
+    are accessed from userspace directly on some PCI host bridge.
+
 Debugging
 
   oops=panic Always panic on oopses. Default is to just kill the process,

arch/x86_64/Kconfig

@@ -405,6 +405,25 @@ config IOMMU
 	  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

arch/x86_64/kernel/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_SOFTWARE_SUSPEND)	+= suspend_asm.o
 obj-$(CONFIG_CPU_FREQ)		+= cpufreq/
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_IOMMU)		+= pci-gart.o aperture.o
+obj-$(CONFIG_CALGARY_IOMMU)	+= pci-calgary.o tce.o
 obj-$(CONFIG_SWIOTLB)		+= pci-swiotlb.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_X86_PM_TIMER)	+= pmtimer.o