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SAMV7: Use sem_reset() instead of sem_init() to set a semaphore count

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This commit is contained in:
Gregory Nutt 2016-03-05 07:44:18 -06:00
parent 5c881e6d2e
commit d938c1cd8c
1 changed files with 10 additions and 11 deletions
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21
arch/arm/src/samv7/sam_mcan.c
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@ -55,6 +55,7 @@
#include <arch/board/board.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/semaphore.h>
#include <nuttx/can.h>
#include "cache.h"
@ -1502,7 +1503,7 @@ static void mcan_buffer_reserve(FAR struct sam_mcan_s *priv)
if (sval > 0)
{
candbg("ERROR: TX FIFOQ full but txfsem is %d\n", sval);
sem_init(&priv->txfsem, 0, 0);
sem_reset(&priv->txfsem, 0);
}
}
@ -1555,21 +1556,19 @@ static void mcan_buffer_reserve(FAR struct sam_mcan_s *priv)
tffl = priv->config->ntxfifoq;
}
/* REVISIT: There may be issues with this logic in a multi-thread
* environment. If there is only a single thread, then certainly
* sval and tff1 should match, but that may not be true in any multi-
* threaded use of this driver.
*/
if (sval != tffl)
{
candbg("ERROR: TX FIFO reports %d but txfsem is %d\n", tffl, sval);
/* REVISIT: The following is dangerous and non-standard usage of the
* semaphore count. It can only work if the count is non-negative.
* If the count because negative, then forcing it to a non-negative
* value will cause the system to hang.
*
* A proper solution might be a loop that calls sem_post() or sem_wait()
* repeteadly to adjust the count.
*/
/* Reset the semaphore count to the Tx FIFO free level. */
DEBUGASSERT(priv->txfsem.count >= 0);
sem_init(&priv->txfsem, 0, tffl);
sem_reset(&priv->txfsem, tffl);
}
#endif