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/*
* Copyright (C) 2010-2011 ARM Limited. All rights reserved.
*
* This program is free software and is provided to you under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation, and any use by you of this program is subject to the terms of such GNU licence.
*
* A copy of the licence is included with the program, and can also be obtained from Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/**
* @file mali_osk_locks.c
* Implemenation of the OS abstraction layer for the kernel device driver
*/
/* needed to detect kernel version specific code */
#include <linux/version.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
#include <linux/semaphore.h>
#else /* pre 2.6.26 the file was in the arch specific location */
#include <asm/semaphore.h>
#endif
#include <linux/slab.h>
#include "mali_osk.h"
#include "mali_kernel_common.h"
/* These are all the locks we implement: */
typedef enum
{
_MALI_OSK_INTERNAL_LOCKTYPE_SPIN, /* Mutex, implicitly non-interruptable, use spin_lock/spin_unlock */
_MALI_OSK_INTERNAL_LOCKTYPE_SPIN_IRQ, /* Mutex, IRQ version of spinlock, use spin_lock_irqsave/spin_unlock_irqrestore */
_MALI_OSK_INTERNAL_LOCKTYPE_MUTEX, /* Interruptable, use up()/down_interruptable() */
_MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT, /* Non-Interruptable, use up()/down() */
_MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT_RW, /* Non-interruptable, Reader/Writer, use {up,down}{read,write}() */
/* Linux supports, but we do not support:
* Non-Interruptable Reader/Writer spinlock mutexes - RW optimization will be switched off
*/
/* Linux does not support:
* One-locks, of any sort - no optimization for this fact will be made.
*/
} _mali_osk_internal_locktype;
struct _mali_osk_lock_t_struct
{
_mali_osk_internal_locktype type;
unsigned long flags;
union
{
spinlock_t spinlock;
struct semaphore sema;
struct rw_semaphore rw_sema;
} obj;
MALI_DEBUG_CODE(
/** original flags for debug checking */
_mali_osk_lock_flags_t orig_flags;
_mali_osk_lock_mode_t locked_as;
); /* MALI_DEBUG_CODE */
};
_mali_osk_lock_t *_mali_osk_lock_init( _mali_osk_lock_flags_t flags, u32 initial, u32 order )
{
_mali_osk_lock_t *lock = NULL;
/* Validate parameters: */
/* Flags acceptable */
MALI_DEBUG_ASSERT( 0 == ( flags & ~(_MALI_OSK_LOCKFLAG_SPINLOCK
| _MALI_OSK_LOCKFLAG_SPINLOCK_IRQ
| _MALI_OSK_LOCKFLAG_NONINTERRUPTABLE
| _MALI_OSK_LOCKFLAG_READERWRITER
| _MALI_OSK_LOCKFLAG_ORDERED
| _MALI_OSK_LOCKFLAG_ONELOCK )) );
/* Spinlocks are always non-interruptable */
MALI_DEBUG_ASSERT( (((flags & _MALI_OSK_LOCKFLAG_SPINLOCK) || (flags & _MALI_OSK_LOCKFLAG_SPINLOCK_IRQ)) && (flags & _MALI_OSK_LOCKFLAG_NONINTERRUPTABLE))
|| !(flags & _MALI_OSK_LOCKFLAG_SPINLOCK));
/* Parameter initial SBZ - for future expansion */
MALI_DEBUG_ASSERT( 0 == initial );
lock = kmalloc(sizeof(_mali_osk_lock_t), GFP_KERNEL);
if ( NULL == lock )
{
return lock;
}
/* Determine type of mutex: */
/* defaults to interruptable mutex if no flags are specified */
if ( (flags & _MALI_OSK_LOCKFLAG_SPINLOCK) )
{
/* Non-interruptable Spinlocks override all others */
lock->type = _MALI_OSK_INTERNAL_LOCKTYPE_SPIN;
spin_lock_init( &lock->obj.spinlock );
}
else if ( (flags & _MALI_OSK_LOCKFLAG_SPINLOCK_IRQ ) )
{
lock->type = _MALI_OSK_INTERNAL_LOCKTYPE_SPIN_IRQ;
lock->flags = 0;
spin_lock_init( &lock->obj.spinlock );
}
else if ( (flags & _MALI_OSK_LOCKFLAG_NONINTERRUPTABLE)
&& (flags & _MALI_OSK_LOCKFLAG_READERWRITER) )
{
lock->type = _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT_RW;
init_rwsem( &lock->obj.rw_sema );
}
else
{
/* Usual mutex types */
if ( (flags & _MALI_OSK_LOCKFLAG_NONINTERRUPTABLE) )
{
lock->type = _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT;
}
else
{
lock->type = _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX;
}
/* Initially unlocked */
sema_init( &lock->obj.sema, 1 );
}
MALI_DEBUG_CODE(
/* Debug tracking of flags */
lock->orig_flags = flags;
lock->locked_as = _MALI_OSK_LOCKMODE_UNDEF;
); /* MALI_DEBUG_CODE */
return lock;
}
_mali_osk_errcode_t _mali_osk_lock_wait( _mali_osk_lock_t *lock, _mali_osk_lock_mode_t mode)
{
_mali_osk_errcode_t err = _MALI_OSK_ERR_OK;
/* Parameter validation */
MALI_DEBUG_ASSERT_POINTER( lock );
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_RW == mode
|| _MALI_OSK_LOCKMODE_RO == mode );
/* Only allow RO locks when the initial object was a Reader/Writer lock
* Since information is lost on the internal locktype, we use the original
* information, which is only stored when built for DEBUG */
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_RW == mode
|| (_MALI_OSK_LOCKMODE_RO == mode && (_MALI_OSK_LOCKFLAG_READERWRITER & lock->orig_flags)) );
switch ( lock->type )
{
case _MALI_OSK_INTERNAL_LOCKTYPE_SPIN:
spin_lock(&lock->obj.spinlock);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_SPIN_IRQ:
spin_lock_irqsave(&lock->obj.spinlock, lock->flags);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX:
if ( down_interruptible(&lock->obj.sema) )
{
err = _MALI_OSK_ERR_RESTARTSYSCALL;
}
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT:
down(&lock->obj.sema);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT_RW:
if (mode == _MALI_OSK_LOCKMODE_RO)
{
down_read(&lock->obj.rw_sema);
}
else
{
down_write(&lock->obj.rw_sema);
}
break;
default:
/* Reaching here indicates a programming error, so you will not get here
* on non-DEBUG builds */
MALI_DEBUG_PRINT_ERROR( ("Invalid internal lock type: %.8X", lock->type ) );
break;
}
/* DEBUG tracking of previously locked state - occurs after lock obtained */
MALI_DEBUG_CODE(
if ( _MALI_OSK_ERR_OK == err )
{
/* Assert that this is not currently locked */
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_UNDEF == lock->locked_as );
lock->locked_as = mode;
}
); /* MALI_DEBUG_CODE */
return err;
}
void _mali_osk_lock_signal( _mali_osk_lock_t *lock, _mali_osk_lock_mode_t mode )
{
/* Parameter validation */
MALI_DEBUG_ASSERT_POINTER( lock );
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_RW == mode
|| _MALI_OSK_LOCKMODE_RO == mode );
/* Only allow RO locks when the initial object was a Reader/Writer lock
* Since information is lost on the internal locktype, we use the original
* information, which is only stored when built for DEBUG */
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_RW == mode
|| (_MALI_OSK_LOCKMODE_RO == mode && (_MALI_OSK_LOCKFLAG_READERWRITER & lock->orig_flags)) );
/* For DEBUG only, assert that we previously locked this, and in the same way (RW/RO) */
MALI_DEBUG_ASSERT( mode == lock->locked_as );
/* DEBUG tracking of previously locked state - occurs before lock released */
MALI_DEBUG_CODE( lock->locked_as = _MALI_OSK_LOCKMODE_UNDEF );
switch ( lock->type )
{
case _MALI_OSK_INTERNAL_LOCKTYPE_SPIN:
spin_unlock(&lock->obj.spinlock);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_SPIN_IRQ:
spin_unlock_irqrestore(&lock->obj.spinlock, lock->flags);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX:
/* FALLTHROUGH */
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT:
up(&lock->obj.sema);
break;
case _MALI_OSK_INTERNAL_LOCKTYPE_MUTEX_NONINT_RW:
if (mode == _MALI_OSK_LOCKMODE_RO)
{
up_read(&lock->obj.rw_sema);
}
else
{
up_write(&lock->obj.rw_sema);
}
break;
default:
/* Reaching here indicates a programming error, so you will not get here
* on non-DEBUG builds */
MALI_DEBUG_PRINT_ERROR( ("Invalid internal lock type: %.8X", lock->type ) );
break;
}
}
void _mali_osk_lock_term( _mali_osk_lock_t *lock )
{
/* Parameter validation */
MALI_DEBUG_ASSERT_POINTER( lock );
/* For DEBUG only, assert that this is not currently locked */
MALI_DEBUG_ASSERT( _MALI_OSK_LOCKMODE_UNDEF == lock->locked_as );
/* Linux requires no explicit termination of spinlocks, semaphores, or rw_semaphores */
kfree(lock);
}
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