diff options
Diffstat (limited to 'include/asm-arm/domain.h')
| -rw-r--r-- | include/asm-arm/domain.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/include/asm-arm/domain.h b/include/asm-arm/domain.h index da1d960387d9..f8ea2de4848e 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 |