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local.h

#ifndef __M32R_LOCAL_H
#define __M32R_LOCAL_H

/*
 *  linux/include/asm-m32r/local.h
 *
 *  M32R version:
 *    Copyright (C) 2001, 2002  Hitoshi Yamamoto
 *    Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
 *    Copyright (C) 2007  Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 */

#include <linux/percpu.h>
#include <asm/assembler.h>
#include <asm/system.h>
#include <asm/local.h>

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

/*
 * Make sure gcc doesn't try to be clever and move things around
 * on us. We need to use _exactly_ the address the user gave us,
 * not some alias that contains the same information.
 */
typedef struct { volatile int counter; } local_t;

#define LOCAL_INIT(i)   { (i) }

/**
 * local_read - read local variable
 * @l: pointer of type local_t
 *
 * Atomically reads the value of @l.
 */
#define local_read(l)   ((l)->counter)

/**
 * local_set - set local variable
 * @l: pointer of type local_t
 * @i: required value
 *
 * Atomically sets the value of @l to @i.
 */
#define local_set(l, i) (((l)->counter) = (i))

/**
 * local_add_return - add long to local variable and return it
 * @i: long value to add
 * @l: pointer of type local_t
 *
 * Atomically adds @i to @l and return (@i + @l).
 */
static inline long local_add_return(long i, local_t *l)
{
      unsigned long flags;
      long result;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_add_return           \n\t"
            DCACHE_CLEAR("%0", "r4", "%1")
            "ld %0, @%1;                  \n\t"
            "add  %0, %2;                 \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (result)
            : "r" (&l->counter), "r" (i)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r4"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);

      return result;
}

/**
 * local_sub_return - subtract long from local variable and return it
 * @i: long value to subtract
 * @l: pointer of type local_t
 *
 * Atomically subtracts @i from @l and return (@l - @i).
 */
static inline long local_sub_return(long i, local_t *l)
{
      unsigned long flags;
      long result;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_sub_return           \n\t"
            DCACHE_CLEAR("%0", "r4", "%1")
            "ld %0, @%1;                  \n\t"
            "sub  %0, %2;                 \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (result)
            : "r" (&l->counter), "r" (i)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r4"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);

      return result;
}

/**
 * local_add - add long to local variable
 * @i: long value to add
 * @l: pointer of type local_t
 *
 * Atomically adds @i to @l.
 */
#define local_add(i, l) ((void) local_add_return((i), (l)))

/**
 * local_sub - subtract the local variable
 * @i: long value to subtract
 * @l: pointer of type local_t
 *
 * Atomically subtracts @i from @l.
 */
#define local_sub(i, l) ((void) local_sub_return((i), (l)))

/**
 * local_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @l: pointer of type local_t
 *
 * Atomically subtracts @i from @l and returns
 * true if the result is zero, or false for all
 * other cases.
 */
#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)

/**
 * local_inc_return - increment local variable and return it
 * @l: pointer of type local_t
 *
 * Atomically increments @l by 1 and returns the result.
 */
static inline long local_inc_return(local_t *l)
{
      unsigned long flags;
      long result;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_inc_return           \n\t"
            DCACHE_CLEAR("%0", "r4", "%1")
            "ld %0, @%1;                  \n\t"
            "addi %0, #1;                 \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (result)
            : "r" (&l->counter)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r4"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);

      return result;
}

/**
 * local_dec_return - decrement local variable and return it
 * @l: pointer of type local_t
 *
 * Atomically decrements @l by 1 and returns the result.
 */
static inline long local_dec_return(local_t *l)
{
      unsigned long flags;
      long result;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_dec_return           \n\t"
            DCACHE_CLEAR("%0", "r4", "%1")
            "ld %0, @%1;                  \n\t"
            "addi %0, #-1;          \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (result)
            : "r" (&l->counter)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r4"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);

      return result;
}

/**
 * local_inc - increment local variable
 * @l: pointer of type local_t
 *
 * Atomically increments @l by 1.
 */
#define local_inc(l) ((void)local_inc_return(l))

/**
 * local_dec - decrement local variable
 * @l: pointer of type local_t
 *
 * Atomically decrements @l by 1.
 */
#define local_dec(l) ((void)local_dec_return(l))

/**
 * local_inc_and_test - increment and test
 * @l: pointer of type local_t
 *
 * Atomically increments @l by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
#define local_inc_and_test(l) (local_inc_return(l) == 0)

/**
 * local_dec_and_test - decrement and test
 * @l: pointer of type local_t
 *
 * Atomically decrements @l by 1 and
 * returns true if the result is 0, or false for all
 * other cases.
 */
#define local_dec_and_test(l) (local_dec_return(l) == 0)

/**
 * local_add_negative - add and test if negative
 * @l: pointer of type local_t
 * @i: integer value to add
 *
 * Atomically adds @i to @l and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
#define local_add_negative(i, l) (local_add_return((i), (l)) < 0)

#define local_cmpxchg(l, o, n) (cmpxchg_local(&((l)->counter), (o), (n)))
#define local_xchg(v, new) (xchg_local(&((l)->counter), new))

/**
 * local_add_unless - add unless the number is a given value
 * @l: pointer of type local_t
 * @a: the amount to add to l...
 * @u: ...unless l is equal to u.
 *
 * Atomically adds @a to @l, so long as it was not @u.
 * Returns non-zero if @l was not @u, and zero otherwise.
 */
static inline int local_add_unless(local_t *l, long a, long u)
{
      long c, old;
      c = local_read(l);
      for (;;) {
            if (unlikely(c == (u)))
                  break;
            old = local_cmpxchg((l), c, c + (a));
            if (likely(old == c))
                  break;
            c = old;
      }
      return c != (u);
}

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)

static inline void local_clear_mask(unsigned long  mask, local_t *addr)
{
      unsigned long flags;
      unsigned long tmp;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_clear_mask           \n\t"
            DCACHE_CLEAR("%0", "r5", "%1")
            "ld %0, @%1;                  \n\t"
            "and  %0, %2;                 \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (tmp)
            : "r" (addr), "r" (~mask)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r5"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);
}

static inline void local_set_mask(unsigned long  mask, local_t *addr)
{
      unsigned long flags;
      unsigned long tmp;

      local_irq_save(flags);
      __asm__ __volatile__ (
            "# local_set_mask       \n\t"
            DCACHE_CLEAR("%0", "r5", "%1")
            "ld %0, @%1;                  \n\t"
            "or   %0, %2;                 \n\t"
            "st %0, @%1;                  \n\t"
            : "=&r" (tmp)
            : "r" (addr), "r" (mask)
            : "memory"
#ifdef CONFIG_CHIP_M32700_TS1
            , "r5"
#endif      /* CONFIG_CHIP_M32700_TS1 */
      );
      local_irq_restore(flags);
}

/* Atomic operations are already serializing on m32r */
#define smp_mb__before_local_dec()  barrier()
#define smp_mb__after_local_dec()   barrier()
#define smp_mb__before_local_inc()  barrier()
#define smp_mb__after_local_inc()   barrier()

/* Use these for per-cpu local_t variables: on some archs they are
 * much more efficient than these naive implementations.  Note they take
 * a variable, not an address.
 */

#define __local_inc(l)        ((l)->a.counter++)
#define __local_dec(l)        ((l)->a.counter++)
#define __local_add(i, l)     ((l)->a.counter += (i))
#define __local_sub(i, l)     ((l)->a.counter -= (i))

/* Use these for per-cpu local_t variables: on some archs they are
 * much more efficient than these naive implementations.  Note they take
 * a variable, not an address.
 */

/* Need to disable preemption for the cpu local counters otherwise we could
   still access a variable of a previous CPU in a non local way. */
#define cpu_local_wrap_v(l)         \
      ({ local_t res__;       \
         preempt_disable();         \
         res__ = (l);               \
         preempt_enable();          \
         res__; })
#define cpu_local_wrap(l)           \
      ({ preempt_disable();         \
         l;                   \
         preempt_enable(); })       \

#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))

#define __cpu_local_inc(l)    cpu_local_inc(l)
#define __cpu_local_dec(l)    cpu_local_dec(l)
#define __cpu_local_add(i, l) cpu_local_add((i), (l))
#define __cpu_local_sub(i, l) cpu_local_sub((i), (l))

#endif /* __M32R_LOCAL_H */

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