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/* MN10300 System definitions
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _ASM_SYSTEM_H
#define _ASM_SYSTEM_H
#include <asm/cpu-regs.h>
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
struct task_struct;
struct thread_struct;
extern asmlinkage
struct task_struct *__switch_to(struct thread_struct *prev,
struct thread_struct *next,
struct task_struct *prev_task);
/* context switching is now performed out-of-line in switch_to.S */
#define switch_to(prev, next, last) \
do { \
current->thread.wchan = (u_long) __builtin_return_address(0); \
(last) = __switch_to(&(prev)->thread, &(next)->thread, (prev)); \
mb(); \
current->thread.wchan = 0; \
} while (0)
#define arch_align_stack(x) (x)
#define nop() asm volatile ("nop")
#endif /* !__ASSEMBLY__ */
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
* to devices.
*
* For now, "wmb()" doesn't actually do anything, as all
* Intel CPU's follow what Intel calls a *Processor Order*,
* in which all writes are seen in the program order even
* outside the CPU.
*
* I expect future Intel CPU's to have a weaker ordering,
* but I'd also expect them to finally get their act together
* and add some real memory barriers if so.
*
* Some non intel clones support out of order store. wmb() ceases to be a
* nop for these.
*/
#define mb() asm volatile ("": : :"memory")
#define rmb() mb()
#define wmb() asm volatile ("": : :"memory")
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#endif
#define set_mb(var, value) do { var = value; mb(); } while (0)
#define set_wmb(var, value) do { var = value; wmb(); } while (0)
#define read_barrier_depends() do {} while (0)
#define smp_read_barrier_depends() do {} while (0)
/*****************************************************************************/
/*
* interrupt control
* - "disabled": run in IM1/2
* - level 0 - GDB stub
* - level 1 - virtual serial DMA (if present)
* - level 5 - normal interrupt priority
* - level 6 - timer interrupt
* - "enabled": run in IM7
*/
#ifdef CONFIG_MN10300_TTYSM
#define MN10300_CLI_LEVEL EPSW_IM_2
#else
#define MN10300_CLI_LEVEL EPSW_IM_1
#endif
#define local_save_flags(x) \
do { \
typecheck(unsigned long, x); \
asm volatile( \
" mov epsw,%0 \n" \
: "=d"(x) \
); \
} while (0)
#define local_irq_disable() \
do { \
asm volatile( \
" and %0,epsw \n" \
" or %1,epsw \n" \
" nop \n" \
" nop \n" \
" nop \n" \
: \
: "i"(~EPSW_IM), "i"(EPSW_IE | MN10300_CLI_LEVEL) \
); \
} while (0)
#define local_irq_save(x) \
do { \
local_save_flags(x); \
local_irq_disable(); \
} while (0)
/*
* we make sure local_irq_enable() doesn't cause priority inversion
*/
#ifndef __ASSEMBLY__
extern unsigned long __mn10300_irq_enabled_epsw;
#endif
#define local_irq_enable() \
do { \
unsigned long tmp; \
\
asm volatile( \
" mov epsw,%0 \n" \
" and %1,%0 \n" \
" or %2,%0 \n" \
" mov %0,epsw \n" \
: "=&d"(tmp) \
: "i"(~EPSW_IM), "r"(__mn10300_irq_enabled_epsw) \
); \
} while (0)
#define local_irq_restore(x) \
do { \
typecheck(unsigned long, x); \
asm volatile( \
" mov %0,epsw \n" \
" nop \n" \
" nop \n" \
" nop \n" \
: \
: "d"(x) \
: "memory", "cc" \
); \
} while (0)
#define irqs_disabled() \
({ \
unsigned long flags; \
local_save_flags(flags); \
(flags & EPSW_IM) <= MN10300_CLI_LEVEL; \
})
/* hook to save power by halting the CPU
* - called from the idle loop
* - must reenable interrupts (which takes three instruction cycles to complete)
*/
#define safe_halt() \
do { \
asm volatile(" or %0,epsw \n" \
" nop \n" \
" nop \n" \
" bset %2,(%1) \n" \
: \
: "i"(EPSW_IE|EPSW_IM), "n"(&CPUM), "i"(CPUM_SLEEP)\
: "cc" \
); \
} while (0)
#define STI or EPSW_IE|EPSW_IM,epsw
#define CLI and ~EPSW_IM,epsw; or EPSW_IE|MN10300_CLI_LEVEL,epsw; nop; nop; nop
/*****************************************************************************/
/*
* MN10300 doesn't actually have an exchange instruction
*/
#ifndef __ASSEMBLY__
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))
static inline
unsigned long __xchg(volatile unsigned long *m, unsigned long val)
{
unsigned long retval;
unsigned long flags;
local_irq_save(flags);
retval = *m;
*m = val;
local_irq_restore(flags);
return retval;
}
#define xchg(ptr, v) \
((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
(unsigned long)(v)))
static inline unsigned long __cmpxchg(volatile unsigned long *m,
unsigned long old, unsigned long new)
{
unsigned long retval;
unsigned long flags;
local_irq_save(flags);
retval = *m;
if (retval == old)
*m = new;
local_irq_restore(flags);
return retval;
}
#define cmpxchg(ptr, o, n) \
((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
(unsigned long)(o), \
(unsigned long)(n)))
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_SYSTEM_H */
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