x86: move GART TLB flushing options to generic code

The GART currently implements the iommu=[no]fullflush command line
parameters which influence its IO/TLB flushing strategy. This patch
makes these parameters generic so that they can be used by the AMD IOMMU
too.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/kernel-parameters.txt

@@ -893,6 +893,10 @@ and is between 256 and 4096 characters. It is defined in the file
 		nomerge
 		forcesac
 		soft
+		fullflush
+			Flush IO/TLB at every deallocation
+		nofullflush
+			Flush IO/TLB only when addresses are reused (default)
 
 
 	intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option

Documentation/x86/x86_64/boot-options.txt

@@ -233,8 +233,6 @@ IOMMU (input/output memory management unit)
   iommu options only relevant to the AMD GART hardware IOMMU:
     <size>             Set the size of the remapping area in bytes.
     allowed            Overwrite iommu off workarounds for specific chipsets.
-    fullflush          Flush IOMMU on each allocation (default).
-    nofullflush        Don't use IOMMU fullflush.
     leak               Turn on simple iommu leak tracing (only when
                        CONFIG_IOMMU_LEAK is on). Default number of leak pages
                        is 20.

arch/x86/kernel/pci-dma.c

@@ -16,6 +16,15 @@ EXPORT_SYMBOL(dma_ops);
 
 static int iommu_sac_force __read_mostly;
 
+/*
+ * If this is disabled the IOMMU will use an optimized flushing strategy
+ * of only flushing when an mapping is reused. With it true the GART is
+ * flushed for every mapping. Problem is that doing the lazy flush seems
+ * to trigger bugs with some popular PCI cards, in particular 3ware (but
+ * has been also also seen with Qlogic at least).
+ */
+int iommu_fullflush;
+
 #ifdef CONFIG_IOMMU_DEBUG
 int panic_on_overflow __read_mostly = 1;
 int force_iommu __read_mostly = 1;
@@ -171,6 +180,10 @@ static __init int iommu_setup(char *p)
 		}
 		if (!strncmp(p, "nomerge", 7))
 			iommu_merge = 0;
+		if (!strncmp(p, "fullflush", 8))
+			iommu_fullflush = 1;
+		if (!strncmp(p, "nofullflush", 11))
+			iommu_fullflush = 0;
 		if (!strncmp(p, "forcesac", 8))
 			iommu_sac_force = 1;
 		if (!strncmp(p, "allowdac", 8))

arch/x86/kernel/pci-gart_64.c

@@ -45,15 +45,6 @@ static unsigned long iommu_pages;	/* .. and in pages */
 
 static u32 *iommu_gatt_base;		/* Remapping table */
 
-/*
- * If this is disabled the IOMMU will use an optimized flushing strategy
- * of only flushing when an mapping is reused. With it true the GART is
- * flushed for every mapping. Problem is that doing the lazy flush seems
- * to trigger bugs with some popular PCI cards, in particular 3ware (but
- * has been also also seen with Qlogic at least).
- */
-int iommu_fullflush = 1;
-
 /* Allocation bitmap for the remapping area: */
 static DEFINE_SPINLOCK(iommu_bitmap_lock);
 /* Guarded by iommu_bitmap_lock: */
@@ -901,10 +892,6 @@ void __init gart_parse_options(char *p)
 #endif
 	if (isdigit(*p) && get_option(&p, &arg))
 		iommu_size = arg;
-	if (!strncmp(p, "fullflush", 8))
-		iommu_fullflush = 1;
-	if (!strncmp(p, "nofullflush", 11))
-		iommu_fullflush = 0;
 	if (!strncmp(p, "noagp", 5))
 		no_agp = 1;
 	if (!strncmp(p, "noaperture", 10))

include/asm-x86/iommu.h

@@ -7,6 +7,7 @@ extern struct dma_mapping_ops nommu_dma_ops;
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
 extern int dmar_disabled;
+extern int iommu_fullflush;
 
 extern unsigned long iommu_num_pages(unsigned long addr, unsigned long len);