[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>

11 files changed, 31 insertions, 26 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
 
diff --git a/arch/x86_64/Kconfig.debug b/arch/x86_64/Kconfig.debug
index ea31b4c62105..0226f08be874 100644
--- a/arch/x86_64/Kconfig.debug
+++ b/arch/x86_64/Kconfig.debug
@@ -13,7 +13,7 @@ config DEBUG_RODATA
          If in doubt, say "N".
 
 config IOMMU_DEBUG
-       depends on GART_IOMMU && DEBUG_KERNEL
+       depends on IOMMU && DEBUG_KERNEL
        bool "Enable IOMMU debugging"
        help
          Force the IOMMU to on even when you have less than 4GB of
diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile
index f927d11065fe..fd106bdddd6d 100644
--- a/arch/x86_64/kernel/Makefile
+++ b/arch/x86_64/kernel/Makefile
@@ -28,7 +28,7 @@ obj-$(CONFIG_PM)		+= suspend.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)  += suspend_asm.o
 obj-$(CONFIG_CPU_FREQ)          += cpufreq/
 obj-$(CONFIG_EARLY_PRINTK)      += early_printk.o
-obj-$(CONFIG_GART_IOMMU)        += pci-gart.o aperture.o
+obj-$(CONFIG_IOMMU)             += pci-gart.o aperture.o
 obj-$(CONFIG_SWIOTLB)           += pci-swiotlb.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
 obj-$(CONFIG_X86_PM_TIMER)      += pmtimer.o
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 519cd4e6f9e7..c768d8a036d0 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -319,7 +319,7 @@ void __init check_ioapic(void)
                                 vendor &= 0xffff;
                                 switch (vendor) { 
                                 case PCI_VENDOR_ID_VIA:
-#ifdef CONFIG_GART_IOMMU
+#ifdef CONFIG_IOMMU
                                         if ((end_pfn > MAX_DMA32_PFN ||
                                              force_iommu) &&
                                             !iommu_aperture_allowed) {
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index 117bcebe9ebc..33926c367250 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -266,7 +266,7 @@ __init int iommu_setup(char *p)
                     swiotlb = 1;
 #endif
 
-#ifdef CONFIG_GART_IOMMU
+#ifdef CONFIG_IOMMU
             gart_parse_options(p);
 #endif
 
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 9dadb9a1db2a..816203d57e11 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -702,7 +702,7 @@ void __init setup_arch(char **cmdline_p)
 
         e820_setup_gap();
 
-#ifdef CONFIG_GART_IOMMU
+#ifdef CONFIG_IOMMU
         iommu_hole_init();
 #endif
 
diff --git a/drivers/char/agp/Kconfig b/drivers/char/agp/Kconfig
index 46685a540772..9826a399fa02 100644
--- a/drivers/char/agp/Kconfig
+++ b/drivers/char/agp/Kconfig
@@ -55,9 +55,9 @@ config AGP_AMD
           X on AMD Irongate, 761, and 762 chipsets.
 
 config AGP_AMD64
-        tristate "AMD Opteron/Athlon64 on-CPU GART support" if !GART_IOMMU
+        tristate "AMD Opteron/Athlon64 on-CPU GART support" if !IOMMU
         depends on AGP && X86
-        default y if GART_IOMMU
+        default y if IOMMU
         help
           This option gives you AGP support for the GLX component of
           X using the on-CPU northbridge of the AMD Athlon64/Opteron CPUs.
diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index 229d015757f9..f690ee8cb732 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -292,7 +292,7 @@ static int __devinit aperture_valid(u64 aper, u32 size)
 /*
  * W*s centric BIOS sometimes only set up the aperture in the AGP
  * bridge, not the northbridge. On AMD64 this is handled early
- * in aperture.c, but when GART_IOMMU is not enabled or we run
+ * in aperture.c, but when IOMMU is not enabled or we run
  * on a 32bit kernel this needs to be redone.
  * Unfortunately it is impossible to fix the aperture here because it's too late
  * to allocate that much memory. But at least error out cleanly instead of
@@ -775,7 +775,7 @@ static void __exit agp_amd64_cleanup(void)
 
 /* On AMD64 the PCI driver needs to initialize this driver early
    for the IOMMU, so it has to be called via a backdoor. */
-#ifndef CONFIG_GART_IOMMU
+#ifndef CONFIG_IOMMU
 module_init(agp_amd64_init);
 module_exit(agp_amd64_cleanup);
 #endif
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index 35b0a6ebd3f5..7cea514e810a 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -104,8 +104,11 @@ static int aac_alloc_comm(struct aac_dev *dev, void **commaddr, unsigned long co
          * always true on real computers. It also has some slight problems
          * with the GART on x86-64. I've btw never tried DMA from PCI space
          * on this platform but don't be surprised if its problematic.
+         * [AK: something is very very wrong when a driver tests this symbol.
+         *  Someone should figure out what the comment writer really meant here and fix
+         *  the code. Or just remove that bad code. ]
          */
-#ifndef CONFIG_GART_IOMMU
+#ifndef CONFIG_IOMMU
         if ((num_physpages << (PAGE_SHIFT - 12)) <= AAC_MAX_HOSTPHYSMEMPAGES) {
                 init->HostPhysMemPages = 
                         cpu_to_le32(num_physpages << (PAGE_SHIFT-12));
diff --git a/include/asm-x86_64/pci.h b/include/asm-x86_64/pci.h
index 2db0620d5449..3374d34c4acd 100644
--- a/include/asm-x86_64/pci.h
+++ b/include/asm-x86_64/pci.h
@@ -52,7 +52,7 @@ extern int iommu_setup(char *opt);
  */
 #define PCI_DMA_BUS_IS_PHYS (dma_ops->is_phys)
 
-#ifdef CONFIG_GART_IOMMU
+#ifdef CONFIG_IOMMU
 
 /*
  * x86-64 always supports DAC, but sometimes it is useful to force
diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h
index 8abf2a43c944..1064533e0959 100644
--- a/include/asm-x86_64/proto.h
+++ b/include/asm-x86_64/proto.h
@@ -116,7 +116,7 @@ extern int skip_ioapic_setup;
 extern int acpi_ht;
 extern int acpi_disabled;
 
-#ifdef CONFIG_GART_IOMMU
+#ifdef CONFIG_IOMMU
 extern int fallback_aper_order;
 extern int fallback_aper_force;
 extern int iommu_aperture;