7df63fcae0
Added --terse and --mailback options to the make stylecheck target. It also does continue even if it enounters a possible error. We decided on two exceptions from the linux kernel coding standard: - Empty wait while loops may end with ; on the same line. - All blocks after while, if, for have to be in brackets even if they only contain one statement. Otherwise it is easy to introduce an error. Checkpatch needs to be adapted to reflect those changes.
68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
/*
|
|
* This file is part of the libopencm3 project.
|
|
*
|
|
* Copyright (C) 2012 Fergus Noble <fergusnoble@gmail.com>
|
|
*
|
|
* This library is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Lesser General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This library 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. See the
|
|
* GNU Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <libopencm3/cm3/sync.h>
|
|
|
|
u32 __ldrex(volatile u32 *addr)
|
|
{
|
|
u32 res;
|
|
__asm__ volatile ("ldrex %0, [%1]" : "=r" (res) : "r" (addr));
|
|
return res;
|
|
}
|
|
|
|
u32 __strex(u32 val, volatile u32 *addr)
|
|
{
|
|
u32 res;
|
|
__asm__ volatile ("strex %0, %2, [%1]"
|
|
: "=&r" (res) : "r" (addr), "r" (val));
|
|
return res;
|
|
}
|
|
|
|
void __dmb()
|
|
{
|
|
__asm__ volatile ("dmb");
|
|
}
|
|
|
|
void mutex_lock(mutex_t *m)
|
|
{
|
|
u32 status = 0;
|
|
|
|
do {
|
|
/* Wait until the mutex is unlocked. */
|
|
while (__ldrex(m) != MUTEX_UNLOCKED);
|
|
|
|
/* Try to acquire it. */
|
|
status = __strex(MUTEX_LOCKED, m);
|
|
|
|
/* Did we get it? If not then try again. */
|
|
} while (status != 0);
|
|
|
|
/* Execute the mysterious Data Memory Barrier instruction! */
|
|
__dmb();
|
|
}
|
|
|
|
void mutex_unlock(mutex_t *m)
|
|
{
|
|
__dmb();
|
|
|
|
/* Free the lock. */
|
|
*m = MUTEX_UNLOCKED;
|
|
}
|
|
|