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[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 <buytenh@wantstofly.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Lennert Buytenhek 2007-03-31 12:03:20 +01:00 committed by Russell King
parent 9a4d93d49d
commit 398e692fd5
1 changed files with 18 additions and 16 deletions
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34
include/asm-arm/system.h
View File

@ -3,6 +3,7 @@
#ifdef __KERNEL__
#include <asm/memory.h>
#define CPU_ARCH_UNKNOWN 0
#define CPU_ARCH_ARMv3 1
@ -154,7 +155,7 @@ extern unsigned int user_debug;
#define vectors_high() (0)
#endif
#if __LINUX_ARM_ARCH__ >= 6
#if defined(CONFIG_CPU_XSC3) || __LINUX_ARM_ARCH__ >= 6
#define isb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
: : "r" (0) : "memory")
#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
@ -168,22 +169,23 @@ extern unsigned int user_debug;
#define dmb() __asm__ __volatile__ ("" : : : "memory")
#endif
#define mb() barrier()
#define rmb() barrier()
#define wmb() barrier()
#define read_barrier_depends() do { } while(0)
#ifdef CONFIG_SMP
#define smp_mb() dmb()
#define smp_rmb() dmb()
#define smp_wmb() dmb()
#define smp_read_barrier_depends() read_barrier_depends()
#ifndef CONFIG_SMP
#define mb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define rmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define wmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() read_barrier_depends()
#endif /* CONFIG_SMP */
#define mb() dmb()
#define rmb() dmb()
#define wmb() dmb()
#define smp_mb() dmb()
#define smp_rmb() dmb()
#define smp_wmb() dmb()
#endif
#define read_barrier_depends() do { } while(0)
#define smp_read_barrier_depends() do { } while(0)
#define set_mb(var, value) do { var = value; smp_mb(); } while (0)
#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");