[ARM] 4298/1: fix memory barriers for DMA coherent and SMP platforms
[ARM] 4298/1: fix memory barriers for DMA coherent and SMP platforms

This patch:
- Switches mb/rmb/wmb back to being full-blown DMBs on ARM SMP systems,
  since mb/rmb/wmb are required to order Normal memory accesses as well.
- Enables the use of DMB and ISB on XSC3 (which is an ARMv5TE ISA core
  but conforms to the ARMv6 memory ordering model and supports the
  various ARMv6 barriers.)
- Makes DMA coherent platforms (only ixp23xx at the moment) map
  mb/rmb/wmb to dmb(), as on DMA coherent platforms, DMA consistent
  mappings are done as Normal mappings, which are weakly ordered.

Signed-off-by: Lennert Buytenhek <8858498612e3a522354216649776e3032dcb7e5b@wantstofly.org>
Acked-by: David Howells <ebac1d06c1688626821bb0e574a037a7a5354e49@redhat.com>
Acked-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>
Acked-by: Paul E. McKenney <1e0ce936bb9b355d257bf5790d2513c3f28be22b@linux.vnet.ibm.com>
Acked-by: Dan Williams <24ee2bf0bd8ac766c348bf1f0639943bac1535c6@intel.com>
Signed-off-by: Russell King <f6aa0246ff943bfa8602cdf60d40c481b38ed232@arm.linux.org.uk>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs