irqflags.h

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/* MN10300 IRQ flag handling
 *
 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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_IRQFLAGS_H
#define _ASM_IRQFLAGS_H

#include <asm/cpu-regs.h>
#ifndef __ASSEMBLY__
#include <linux/smp.h>
#endif

/*
 * interrupt control
 * - "disabled": run in IM1/2
 *   - level 0 - kernel debugger
 *   - level 1 - virtual serial DMA (if present)
 *   - level 5 - normal interrupt priority
 *   - level 6 - timer interrupt
 * - "enabled":  run in IM7
 */
#define MN10300_CLI_LEVEL   (CONFIG_LINUX_CLI_LEVEL << EPSW_IM_SHIFT)

#ifndef __ASSEMBLY__

static inline unsigned long arch_local_save_flags(void)
{
    unsigned long flags;

    asm volatile("mov epsw,%0" : "=d"(flags));
    return flags;
}

static inline void arch_local_irq_disable(void)
{
    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)
        : "memory");
}

static inline unsigned long arch_local_irq_save(void)
{
    unsigned long flags;

    flags = arch_local_save_flags();
    arch_local_irq_disable();
    return flags;
}

/*
 * we make sure arch_irq_enable() doesn't cause priority inversion
 */
extern unsigned long __mn10300_irq_enabled_epsw[];

static inline void arch_local_irq_enable(void)
{
    unsigned long tmp;
    int cpu = raw_smp_processor_id();

    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[cpu])
        : "memory", "cc");
}

static inline void arch_local_irq_restore(unsigned long flags)
{
    asm volatile(
        "   mov %0,epsw \n"
        "   nop     \n"
        "   nop     \n"
        "   nop     \n"
        :
        : "d"(flags)
        : "memory", "cc");
}

static inline bool arch_irqs_disabled_flags(unsigned long flags)
{
    return (flags & (EPSW_IE | EPSW_IM)) != (EPSW_IE | EPSW_IM_7);
}

static inline bool arch_irqs_disabled(void)
{
    return arch_irqs_disabled_flags(arch_local_save_flags());
}

/*
 * Hook to save power by halting the CPU
 * - called from the idle loop
 * - must reenable interrupts (which takes three instruction cycles to complete)
 */
static inline void arch_safe_halt(void)
{
#ifdef CONFIG_SMP
    arch_local_irq_enable();
#else
    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");
#endif
}

#define __sleep_cpu()               \
do {                        \
    asm volatile(               \
        "   bset    %1,(%0)\n"  \
        "1: btst    %1,(%0)\n"  \
        "   bne 1b\n"       \
        :               \
        : "i"(&CPUM), "i"(CPUM_SLEEP)   \
        : "cc"              \
        );              \
} while (0)

static inline void arch_local_cli(void)
{
    asm volatile(
        "   and %0,epsw     \n"
        "   nop         \n"
        "   nop         \n"
        "   nop         \n"
        :
        : "i"(~EPSW_IE)
        : "memory"
        );
}

static inline unsigned long arch_local_cli_save(void)
{
    unsigned long flags = arch_local_save_flags();
    arch_local_cli();
    return flags;
}

static inline void arch_local_sti(void)
{
    asm volatile(
        "   or  %0,epsw     \n"
        :
        : "i"(EPSW_IE)
        : "memory");
}

static inline void arch_local_change_intr_mask_level(unsigned long level)
{
    asm volatile(
        "   and %0,epsw     \n"
        "   or  %1,epsw     \n"
        :
        : "i"(~EPSW_IM), "i"(EPSW_IE | level)
        : "cc", "memory");
}

#else /* !__ASSEMBLY__ */

#define LOCAL_SAVE_FLAGS(reg)           \
    mov epsw,reg

#define LOCAL_IRQ_DISABLE               \
    and ~EPSW_IM,epsw;              \
    or  EPSW_IE|MN10300_CLI_LEVEL,epsw;     \
    nop;                        \
    nop;                        \
    nop

#define LOCAL_IRQ_ENABLE        \
    or  EPSW_IE|EPSW_IM_7,epsw

#define LOCAL_IRQ_RESTORE(reg)  \
    mov reg,epsw

#define LOCAL_CLI_SAVE(reg) \
    mov epsw,reg;   \
    and ~EPSW_IE,epsw;  \
    nop;            \
    nop;            \
    nop

#define LOCAL_CLI       \
    and ~EPSW_IE,epsw;  \
    nop;            \
    nop;            \
    nop

#define LOCAL_STI       \
    or  EPSW_IE,epsw

#define LOCAL_CHANGE_INTR_MASK_LEVEL(level) \
    and ~EPSW_IM,epsw;          \
    or  EPSW_IE|(level),epsw

#endif /* __ASSEMBLY__ */
#endif /* _ASM_IRQFLAGS_H */