/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* Do not include directly; use <asm/atomic.h>.
*/
#ifndef _ASM_TILE_ATOMIC_32_H
#define _ASM_TILE_ATOMIC_32_H
#include <arch/chip.h>
#ifndef __ASSEMBLY__
/* Tile-specific routines to support <asm/atomic.h>. */
int _atomic_xchg(atomic_t *v, int n);
int _atomic_xchg_add(atomic_t *v, int i);
int _atomic_xchg_add_unless(atomic_t *v, int a, int u);
int _atomic_cmpxchg(atomic_t *v, int o, int n);
/**
* atomic_xchg - atomically exchange contents of memory with a new value
* @v: pointer of type atomic_t
* @i: integer value to store in memory
*
* Atomically sets @v to @i and returns old @v
*/
static inline int atomic_xchg(atomic_t *v, int n)
{
smp_mb(); /* barrier for proper semantics */
return _atomic_xchg(v, n);
}
/**
* atomic_cmpxchg - atomically exchange contents of memory if it matches
* @v: pointer of type atomic_t
* @o: old value that memory should have
* @n: new value to write to memory if it matches
*
* Atomically checks if @v holds @o and replaces it with @n if so.
* Returns the old value at @v.
*/
static inline int atomic_cmpxchg(atomic_t *v, int o, int n)
{
smp_mb(); /* barrier for proper semantics */
return _atomic_cmpxchg(v, o, n);
}
/**
* atomic_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v.
*/
static inline void atomic_add(int i, atomic_t *v)
{
_atomic_xchg_add(v, i);
}
/**
* atomic_add_return - add integer and return
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns @i + @v
*/
static inline int atomic_add_return(int i, atomic_t *v)
{
smp_mb(); /* barrier for proper semantics */
return _atomic_xchg_add(v, i) + i;
}
/**
* atomic_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as @v was not already @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
smp_mb(); /* barrier for proper semantics */
return _atomic_xchg_add_unless(v, a, u) != u;
}
/**
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*
* atomic_set() can't be just a raw store, since it would be lost if it
* fell between the load and store of one of the other atomic ops.
*/
static inline void atomic_set(atomic_t *v, int n)
{
_atomic_xchg(v, n);
}
#define xchg(ptr, x) ((typeof(*(ptr))) \
((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
atomic_xchg((atomic_t *)(ptr), (long)(x)) : \
__xchg_called_with_bad_pointer()))
#define cmpxchg(ptr, o, n) ((typeof(*(ptr))) \
((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
atomic_cmpxchg((atomic_t *)(ptr), (long)(o), (long)(n)) : \
__cmpxchg_called_with_bad_pointer()))
/* A 64bit atomic type */
typedef struct {
u64 __aligned(8) counter;
} atomic64_t;
#define ATOMIC64_INIT(val) { (val) }
u64 _atomic64_xchg(atomic64_t *v, u64 n);
u64 _atomic64_xchg_add(atomic64_t *v, u64 i);
u64 _atomic64_xchg_add_unless(atomic64_t *v, u64 a, u64 u);
u64 _atomic64_cmpxchg(atomic64_t *v, u64 o, u64 n);
/**
* atomic64_read - read atomic variable
* @v: pointer of type atomic64_t
*
* Atomically reads the value of @v.
*/
static inline u64 atomic64_read(const atomic64_t *v)
{
/*
* Requires an atomic op to read both 32-bit parts consistently.
* Casting away const is safe since the atomic support routines
* do not write to memory if the value has not been modified.
*/
return _atomic64_xchg_add((atomic64_t *)v, 0);
}
/**
* atomic64_xchg - atomically exchange contents of memory with a new value
* @v: pointer of type atomic64_t
* @i: integer value to store in memory
*
* Atomically sets @v to @i and returns old @v
*/
static inline u64 atomic64_xchg(atomic64_t *v, u64 n)
{
smp_mb(); /* barrier for proper semantics */
return _atomic64_xchg(v, n);
}
/**
* atomic64_cmpxchg - atomically exchange contents of memory if it matches
* @v: pointer of type atomic64_t
* @o: old value that memory should have
* @n: new value to write to memory if it matches
*
* Atomically checks if @v holds @o and replaces it with @n if so.
* Returns the old value at @v.
*/
static inline u64 atomic64_cmpxchg(atomic64_t *v, u64 o, u64 n)
{
smp_mb(); /* barrier for proper semantics */
return _atomic64_cmpxchg(v, o, n);
}
/**
* atomic64_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic64_t
*
* Atomically adds @i to @v.
*/
static inline void atomic64_add(u64 i, atomic64_t *v)
{
_atomic64_xchg_add(v, i);
}
/**
* atomic64_add_return - add integer and return
* @v: pointer of type atomic64_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns @i + @v
*/
static inline u64 atomic64_add_return(u64 i, atomic64_t *v)
{
smp_mb(); /* barrier for proper semantics */
return _atomic64_xchg_add(v, i) + i;
}
/**
* atomic64_add_unless - add unless the number is already a given value
* @v: pointer of type atomic64_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as @v was not already @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static inline u64 atomic64_add_unless(atomic64_t *v, u64 a, u64 u)
{
smp_mb(); /* barrier for proper semantics */
return _atomic64_xchg_add_unless(v, a, u) != u;
}
/**
* atomic64_set - set atomic variable
* @v: pointer of type atomic64_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*
* atomic64_set() can't be just a raw store, since it would be lost if it
* fell between the load and store of one of the other atomic ops.
*/
static inline void atomic64_set(atomic64_t *v, u64 n)
{
_atomic64_xchg(v, n);
}
#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
#define atomic64_inc(v) atomic64_add(1LL, (v))
#define atomic64_inc_return(v) atomic64_add_return(1LL, (v))
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
#define atomic64_sub_return(i, v) atomic64_add_return(-(i), (v))
#define atomic64_sub_and_test(a, v) (atomic64_sub_return((a), (v)) == 0)
#define atomic64_sub(i, v) atomic64_add(-(i), (v))
#define atomic64_dec(v) atomic64_sub(1LL, (v))
#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v))
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
/*
* We need to barrier before modifying the word, since the _atomic_xxx()
* routines just tns the lock and then read/modify/write of the word.
* But after the word is updated, the routine issues an "mf" before returning,
* and since it's a function call, we don't even need a compiler barrier.
*/
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__before_atomic_inc() smp_mb()
#define smp_mb__after_atomic_dec() do { } while (0)
#define smp_mb__after_atomic_inc() do { } while (0)
/*
* Support "tns" atomic integers. These are atomic integers that can
* hold any value but "1". They are more efficient than regular atomic
* operations because the "lock" (aka acquire) step is a single "tns"
* in the uncontended case, and the "unlock" (aka release) step is a
* single "store" without an mf. (However, note that on tilepro the
* "tns" will evict the local cache line, so it's not all upside.)
*
* Note that you can ONLY observe the value stored in the pointer
* using these operations; a direct read of the value may confusingly
* return the special value "1".
*/
int __tns_atomic_acquire(atomic_t *);
void __tns_atomic_release(atomic_t *p, int v);
static inline void tns_atomic_set(atomic_t *v, int i)
{
__tns_atomic_acquire(v);
__tns_atomic_release(v, i);
}
static inline int tns_atomic_cmpxchg(atomic_t *v, int o, int n)
{
int ret = __tns_atomic_acquire(v);
__tns_atomic_release(v, (ret == o) ? n : ret);
return ret;
}
static inline int tns_atomic_xchg(atomic_t *v, int n)
{
int ret = __tns_atomic_acquire(v);
__tns_atomic_release(v, n);
return ret;
}
#endif /* !__ASSEMBLY__ */
/*
* Internal definitions only beyond this point.
*/
#define ATOMIC_LOCKS_FOUND_VIA_TABLE() \
(!CHIP_HAS_CBOX_HOME_MAP() && defined(CONFIG_SMP))
#if ATOMIC_LOCKS_FOUND_VIA_TABLE()
/* Number of entries in atomic_lock_ptr[]. */
#define ATOMIC_HASH_L1_SHIFT 6
#define ATOMIC_HASH_L1_SIZE (1 << ATOMIC_HASH_L1_SHIFT)
/* Number of locks in each struct pointed to by atomic_lock_ptr[]. */
#define ATOMIC_HASH_L2_SHIFT (CHIP_L2_LOG_LINE_SIZE() - 2)
#define ATOMIC_HASH_L2_SIZE (1 << ATOMIC_HASH_L2_SHIFT)
#else /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
/*
* Number of atomic locks in atomic_locks[]. Must be a power of two.
* There is no reason for more than PAGE_SIZE / 8 entries, since that
* is the maximum number of pointer bits we can use to index this.
* And we cannot have more than PAGE_SIZE / 4, since this has to
* fit on a single page and each entry takes 4 bytes.
*/
#define ATOMIC_HASH_SHIFT (PAGE_SHIFT - 3)
#define ATOMIC_HASH_SIZE (1 << ATOMIC_HASH_SHIFT)
#ifndef __ASSEMBLY__
extern int atomic_locks[];
#endif
#endif /* ATOMIC_LOCKS_FOUND_VIA_TABLE() */
/*
* All the code that may fault while holding an atomic lock must
* place the pointer to the lock in ATOMIC_LOCK_REG so the fault code
* can correctly release and reacquire the lock. Note that we
* mention the register number in a comment in "lib/atomic_asm.S" to help
* assembly coders from using this register by mistake, so if it
* is changed here, change that comment as well.
*/
#define ATOMIC_LOCK_REG 20
#define ATOMIC_LOCK_REG_NAME r20
#ifndef __ASSEMBLY__
/* Called from setup to initialize a hash table to point to per_cpu locks. */
void __init_atomic_per_cpu(void);
#ifdef CONFIG_SMP
/* Support releasing the atomic lock in do_page_fault_ics(). */
void __atomic_fault_unlock(int *lock_ptr);
#endif
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_TILE_ATOMIC_32_H */
