diff options
author | Joel Sherrill <joel.sherrill@OARcorp.com> | 2006-04-24 16:58:41 +0000 |
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committer | Joel Sherrill <joel.sherrill@OARcorp.com> | 2006-04-24 16:58:41 +0000 |
commit | cadb5d1641059adb5bbef5900e2cefee653f2b74 (patch) | |
tree | 6353a9fe2f02c1b89b69e6cf55eef27d24710ce7 /c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c | |
parent | 2006-04-24 Joel Sherrill <joel@OARcorp.com> (diff) | |
download | rtems-cadb5d1641059adb5bbef5900e2cefee653f2b74.tar.bz2 |
2006-04-24 Jiri Gaisler <jiri@gaisler.com>
Edvin Catovic <edvin@gaisler.com>
PR bsps/972
* ChangeLog, Makefile.am, configure.ac, amba/amba.c, clock/ckinit.c,
console/Makefile.am, console/console.c, console/debugputs.c,
include/Makefile.am, include/amba.h, include/bsp.h, include/leon.h,
leon_smc91111/leon_smc91111.c, startup/bspstart.c, timer/timer.c,
tools/Makefile.am, wrapup/Makefile.am: Added Shared Memory Support
Driver. Added Leon Gaisler Research Ethernet support. Enhanced AMBA
bus support.
* console/debugprintf.c, console/spacewire.c, include/spacewire.h,
leon_greth/.cvsignore, leon_greth/Makefile.am,
leon_greth/leon_greth.c, shmsupp/.cvsignore, shmsupp/Makefile.am,
shmsupp/addrconv.c, shmsupp/getcfg.c, shmsupp/lock.c,
shmsupp/mpisr.c: New files.
Diffstat (limited to 'c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c')
-rw-r--r-- | c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c b/c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c new file mode 100644 index 0000000000..a750f818ac --- /dev/null +++ b/c/src/lib/libbsp/sparc/leon3/shmsupp/lock.c @@ -0,0 +1,97 @@ +/* Shared Memory Lock Routines + * + * This shared memory locked queue support routine need to be + * able to lock the specified locked queue. Interrupts are + * disabled while the queue is locked to prevent preemption + * and deadlock when two tasks poll for the same lock. + * previous level. + * + * COPYRIGHT (c) 1989-1999. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + * + * lock.c,v 1.9.4.1 2003/09/04 18:44:56 joel Exp + */ + +#include <rtems.h> +#include <bsp.h> +#include <shm_driver.h> + + +/* + * Shm_Initialize_lock + * + * Initialize the lock for the specified locked queue. + */ + +void Shm_Initialize_lock( + Shm_Locked_queue_Control *lq_cb +) +{ + lq_cb->lock = LQ_UNLOCKED; +} + +/* void _Shm_Lock( &lq_cb ) + * + * This shared memory locked queue support routine locks the + * specified locked queue. It disables interrupts to prevent + * a deadlock condition. + */ + +asm( + ".text\n" + ".align 4\n" +"LEON3_Atomic_Swap:\n" +" retl\n" +" swapa [%o1] 1, %o0\n" +); + + + +void Shm_Lock( + Shm_Locked_queue_Control *lq_cb +) +{ + rtems_unsigned32 isr_level; + rtems_unsigned32 *lockptr = (rtems_unsigned32 *) &lq_cb->lock; + rtems_unsigned32 lock_value; + + lock_value = SHM_LOCK_VALUE; + rtems_interrupt_disable( isr_level ); + + Shm_isrstat = isr_level; + while ( lock_value ) { + lock_value = LEON3_Atomic_Swap(lock_value, lockptr); +/* asm volatile( "" */ +/* : "=r" (lockptr), "=r" (lock_value) */ +/* : "0" (lockptr), "1" (lock_value) */ +/* ); */ + /* + * If not available, then may want to delay to reduce load on lock. + */ + +/* if ( lock_value ) */ +/* rtems_bsp_delay( 10 ); /\* approximately 10 microseconds *\/ */ + } +} + +/* + * Shm_Unlock + * + * Unlock the lock for the specified locked queue. + */ + +void Shm_Unlock( + Shm_Locked_queue_Control *lq_cb +) +{ + rtems_unsigned32 isr_level; + + lq_cb->lock = SHM_UNLOCK_VALUE; + isr_level = Shm_isrstat; + rtems_interrupt_enable( isr_level ); +} + |