Simplified CAN state machine.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7766 35acf78f-673a-0410-8e92-d51de3d6d3f4

1 files changed, 20 insertions, 15 deletions

diff --git a/os/hal/src/can.c b/os/hal/src/can.c
index 08cdd5172..f6ef7011f 100644
--- a/os/hal/src/can.c
+++ b/os/hal/src/can.c
@@ -85,9 +85,9 @@ void canObjectInit(CANDriver *canp) {
 

 /**

  * @brief   Configures and activates the CAN peripheral.

- * @note    Activating the CAN bus can be a slow operation this this function

- *          is not atomic, it waits internally for the initialization to

- *          complete.

+ * @note    Activating the CAN bus can be a slow operation.

+ * @note    Unlike other drivers it is not possible to restart the CAN

+ *          driver without first stopping it using canStop().

  *

  * @param[in] canp      pointer to the @p CANDriver object

  * @param[in] config    pointer to the @p CANConfig object. Depending on

@@ -100,18 +100,18 @@ void canStart(CANDriver *canp, const CANConfig *config) {
   osalDbgCheck(canp != NULL);

 

   osalSysLock();

-  osalDbgAssert((canp->state == CAN_STOP) ||

-                (canp->state == CAN_STARTING) ||

-                (canp->state == CAN_READY),

-                "invalid state");

-  while (canp->state == CAN_STARTING) {

-    osalThreadSleepS((systime_t)1);

-  }

-  if (canp->state == CAN_STOP) {

-    canp->config = config;

-    can_lld_start(canp);

-    canp->state = CAN_READY;

-  }

+  osalDbgAssert(canp->state == CAN_STOP, "invalid state");

+

+  /* Entering initialization mode. */

+  canp->state = CAN_STARTING;

+  canp->config = config;

+

+  /* Low level initialization, could be a slow process and sleeps could

+     be performed inside.*/

+  can_lld_start(canp);

+

+  /* The driver finally goes into the ready state.*/

+  canp->state = CAN_READY;

   osalSysUnlock();

 }

 

@@ -129,8 +129,13 @@ void canStop(CANDriver *canp) {
   osalSysLock();

   osalDbgAssert((canp->state == CAN_STOP) || (canp->state == CAN_READY),

                 "invalid state");

+

+  /* The low level driver is stopped.*/

   can_lld_stop(canp);

   canp->state  = CAN_STOP;

+

+  /* Threads waiting on CAN APIs are notified that the driver has been

+     stopped in order to not have stuck threads.*/

   osalThreadDequeueAllI(&canp->rxqueue, MSG_RESET);

   osalThreadDequeueAllI(&canp->txqueue, MSG_RESET);

   osalOsRescheduleS();