irqflags.h

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/* FR-V interrupt 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

/*
 * interrupt flag manipulation
 * - use virtual interrupt management since touching the PSR is slow
 *   - ICC2.Z: T if interrupts virtually disabled
 *   - ICC2.C: F if interrupts really disabled
 * - if Z==1 upon interrupt:
 *   - C is set to 0
 *   - interrupts are really disabled
 *   - entry.S returns immediately
 * - uses TIHI (TRAP if Z==0 && C==0) #2 to really reenable interrupts
 *   - if taken, the trap:
 *     - sets ICC2.C
 *     - enables interrupts
 */
static inline void arch_local_irq_disable(void)
{
    /* set Z flag, but don't change the C flag */
    asm volatile("  andcc   gr0,gr0,gr0,icc2    \n"
             :
             :
             : "memory", "icc2"
             );
}

static inline void arch_local_irq_enable(void)
{
    /* clear Z flag and then test the C flag */
    asm volatile("  oricc   gr0,#1,gr0,icc2     \n"
             "  tihi    icc2,gr0,#2     \n"
             :
             :
             : "memory", "icc2"
             );
}

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

    asm volatile("movsg ccr,%0"
             : "=r"(flags)
             :
             : "memory");

    /* shift ICC2.Z to bit 0 */
    flags >>= 26;

    /* make flags 1 if interrupts disabled, 0 otherwise */
    return flags & 1UL;

}

static inline unsigned long arch_local_irq_save(void)
{
    unsigned long flags = arch_local_save_flags();
    arch_local_irq_disable();
    return flags;
}

static inline void arch_local_irq_restore(unsigned long flags)
{
    /* load the Z flag by turning 1 if disabled into 0 if disabled
     * and thus setting the Z flag but not the C flag */
    asm volatile("  xoricc  %0,#1,gr0,icc2      \n"
             /* then trap if Z=0 and C=0 */
             "  tihi    icc2,gr0,#2     \n"
             :
             : "r"(flags)
             : "memory", "icc2"
             );

}

static inline bool arch_irqs_disabled_flags(unsigned long flags)
{
    return flags;
}

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

/*
 * real interrupt flag manipulation
 */
#define __arch_local_irq_disable()          \
do {                            \
    unsigned long psr;              \
    asm volatile("  movsg   psr,%0      \n" \
             "  andi    %0,%2,%0    \n" \
             "  ori %0,%1,%0    \n" \
             "  movgs   %0,psr      \n" \
             : "=r"(psr)            \
             : "i" (PSR_PIL_14), "i" (~PSR_PIL) \
             : "memory");           \
} while (0)

#define __arch_local_irq_enable()           \
do {                            \
    unsigned long psr;              \
    asm volatile("  movsg   psr,%0      \n" \
             "  andi    %0,%1,%0    \n" \
             "  movgs   %0,psr      \n" \
             : "=r"(psr)            \
             : "i" (~PSR_PIL)           \
             : "memory");           \
} while (0)

#define __arch_local_save_flags(flags)      \
do {                        \
    typecheck(unsigned long, flags);    \
    asm("movsg psr,%0"          \
        : "=r"(flags)           \
        :                   \
        : "memory");            \
} while (0)

#define __arch_local_irq_save(flags)            \
do {                            \
    unsigned long npsr;             \
    typecheck(unsigned long, flags);        \
    asm volatile("  movsg   psr,%0      \n" \
             "  andi    %0,%3,%1    \n" \
             "  ori %1,%2,%1    \n" \
             "  movgs   %1,psr      \n" \
             : "=r"(flags), "=r"(npsr)      \
             : "i" (PSR_PIL_14), "i" (~PSR_PIL) \
             : "memory");           \
} while (0)

#define __arch_local_irq_restore(flags)         \
do {                            \
    typecheck(unsigned long, flags);        \
    asm volatile("  movgs   %0,psr      \n" \
             :                  \
             : "r" (flags)          \
             : "memory");           \
} while (0)

#define __arch_irqs_disabled()          \
    ((__get_PSR() & PSR_PIL) >= PSR_PIL_14)

#endif /* _ASM_IRQFLAGS_H */