X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Fasm-arm%2Fdomain.h;h=4c2885abbe6c950f04d06c6345bb6358f591421b;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=da1d960387d9880f2fa602b028aca633719fc3f0;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git

diff --git a/include/asm-arm/domain.h b/include/asm-arm/domain.h
index da1d96038..4c2885abb 100644
--- a/include/asm-arm/domain.h
+++ b/include/asm-arm/domain.h
@@ -16,11 +16,29 @@
  *  DOMAIN_IO     - domain 2 includes all IO only
  *  DOMAIN_USER   - domain 1 includes all user memory only
  *  DOMAIN_KERNEL - domain 0 includes all kernel memory only
+ *
+ * The domain numbering depends on whether we support 36 physical
+ * address for I/O or not.  Addresses above the 32 bit boundary can
+ * only be mapped using supersections and supersections can only
+ * be set for domain 0.  We could just default to DOMAIN_IO as zero,
+ * but there may be systems with supersection support and no 36-bit
+ * addressing.  In such cases, we want to map system memory with
+ * supersections to reduce TLB misses and footprint.
+ *
+ * 36-bit addressing and supersections are only available on
+ * CPUs based on ARMv6+ or the Intel XSC3 core.
  */
+#ifndef CONFIG_IO_36
 #define DOMAIN_KERNEL	0
 #define DOMAIN_TABLE	0
 #define DOMAIN_USER	1
 #define DOMAIN_IO	2
+#else
+#define DOMAIN_KERNEL	2
+#define DOMAIN_TABLE	2
+#define DOMAIN_USER	1
+#define DOMAIN_IO	0
+#endif
 
 /*
  * Domain types
@@ -32,6 +50,8 @@
 #define domain_val(dom,type)	((type) << (2*(dom)))
 
 #ifndef __ASSEMBLY__
+
+#ifdef CONFIG_MMU
 #define set_domain(x)					\
 	do {						\
 	__asm__ __volatile__(				\
@@ -48,5 +68,10 @@
 	set_domain(thread->cpu_domain);				\
 	} while (0)
 
+#else
+#define set_domain(x)		do { } while (0)
+#define modify_domain(dom,type)	do { } while (0)
+#endif
+
 #endif
 #endif /* !__ASSEMBLY__ */