text: /*
   * Copyright (C) 2004-2006 Atmel Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #ifndef __ASM_AVR32_SYSTEM_H
  #define __ASM_AVR32_SYSTEM_H
  
  #include <linux/compiler.h>
  #include <linux/linkage.h>
  #include <linux/types.h>
  
  #include <asm/ptrace.h>
  #include <asm/sysreg.h>
  
  #define xchg(ptr,x) \
  	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  
  #define nop() asm volatile("nop")
  
  #define mb()			asm volatile("" : : : "memory")
  #define rmb()			mb()
  #define wmb()			asm volatile("sync 0" : : : "memory")
  #define read_barrier_depends()  do { } while(0)
  #define set_mb(var, value)      do { var = value; mb(); } while(0)
  
  /*
   * Help PathFinder and other Nexus-compliant debuggers keep track of
   * the current PID by emitting an Ownership Trace Message each time we
   * switch task.
   */
  #ifdef CONFIG_OWNERSHIP_TRACE
  #include <asm/ocd.h>
  #define finish_arch_switch(prev)			\
  	do {						\
  		__mtdr(DBGREG_PID, prev->pid);		\
  		__mtdr(DBGREG_PID, current->pid);	\
  	} while(0)
  #endif
  
  /*
   * switch_to(prev, next, last) should switch from task `prev' to task
   * `next'. `prev' will never be the same as `next'.
   *
   * We just delegate everything to the __switch_to assembly function,
   * which is implemented in arch/avr32/kernel/switch_to.S
   *
   * mb() tells GCC not to cache `current' across this call.
   */
  struct cpu_context;
  struct task_struct;
  extern struct task_struct *__switch_to(struct task_struct *,
  				       struct cpu_context *,
  				       struct cpu_context *);
  #define switch_to(prev, next, last)					\
  	do {								\
  		last = __switch_to(prev, &prev->thread.cpu_context + 1,	\
  				   &next->thread.cpu_context);		\
  	} while (0)
  
  #ifdef CONFIG_SMP
  # error "The AVR32 port does not support SMP"
  #else
  # define smp_mb()		barrier()
  # define smp_rmb()		barrier()
  # define smp_wmb()		barrier()
  # define smp_read_barrier_depends() do { } while(0)
  #endif
  
  #include <linux/irqflags.h>
  
  extern void __xchg_called_with_bad_pointer(void);
  
  #ifdef __CHECKER__
  extern unsigned long __builtin_xchg(void *ptr, unsigned long x);
  #endif
  
  #define xchg_u32(val, m) __builtin_xchg((void *)m, val)
  
  static inline unsigned long __xchg(unsigned long x,
  				       volatile void *ptr,
  				       int size)
  {
  	switch(size) {
  	case 4:
  		return xchg_u32(x, ptr);
  	default:
  		__xchg_called_with_bad_pointer();
  		return x;
  	}
  }
  
  static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
  					  unsigned long new)
  {
  	__u32 ret;
  
  	asm volatile(
  		"1:	ssrf	5\n"
  		"	ld.w	%[ret], %[m]\n"
  		"	cp.w	%[ret], %[old]\n"
  		"	brne	2f\n"
  		"	stcond	%[m], %[new]\n"
  		"	brne	1b\n"
  		"2:\n"
  		: [ret] "=&r"(ret), [m] "=m"(*m)
  		: "m"(m), [old] "ir"(old), [new] "r"(new)
  		: "memory", "cc");
  	return ret;
  }
  
  extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
          volatile int * m, unsigned long old, unsigned long new);
  #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
  
  /* This function doesn't exist, so you'll get a linker error
     if something tries to do an invalid cmpxchg().  */
  extern void __cmpxchg_called_with_bad_pointer(void);
  
  #define __HAVE_ARCH_CMPXCHG 1
  
  static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
  				      unsigned long new, int size)
  {
  	switch (size) {
  	case 4:
  		return __cmpxchg_u32(ptr, old, new);
  	case 8:
  		return __cmpxchg_u64(ptr, old, new);
  	}
  
  	__cmpxchg_called_with_bad_pointer();
  	return old;
  }
  
  #define cmpxchg(ptr, old, new)					\
  	((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old),	\
  				   (unsigned long)(new),	\
  				   sizeof(*(ptr))))
  
  struct pt_regs;
  void NORET_TYPE die(const char *str, struct pt_regs *regs, long err);
  void _exception(long signr, struct pt_regs *regs, int code,
  		unsigned long addr);
  
  #define arch_align_stack(x)	(x)
  
  #endif /* __ASM_AVR32_SYSTEM_H */
  