Simplified CAN state machine.

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

3 files changed, 22 insertions, 21 deletions

diff --git a/os/hal/dox/can.dox b/os/hal/dox/can.dox
index 6c39a52b3..234cb2dc6 100644
--- a/os/hal/dox/can.dox
+++ b/os/hal/dox/can.dox
@@ -48,10 +48,9 @@
     stop -> stop [label="\ncanStop()"];

     stop -> ready [label="\ncanStart()\n(fast implementation)"];

     stop -> starting [label="\ncanStart()\n(slow implementation)"];

-    starting -> starting [label="\ncanStart()\n(other thread)"];

     starting -> ready [label="\ninitialization complete\n(all threads)"];

     ready -> stop [label="\ncanStop()"];

-    ready -> ready [label="\ncanStart()\ncanReceive()\ncanTransmit()"];

+    ready -> ready [label="\ncanReceive()\ncanTransmit()"];

     ready -> sleep [label="\ncanSleep()"];

     sleep -> sleep [label="\ncanSleep()"];

     sleep -> ready [label="\ncanWakeup()"];

diff --git a/os/hal/ports/STM32/LLD/can_lld.c b/os/hal/ports/STM32/LLD/can_lld.c
index 06294ab26..44cb95281 100644
--- a/os/hal/ports/STM32/LLD/can_lld.c
+++ b/os/hal/ports/STM32/LLD/can_lld.c
@@ -429,14 +429,11 @@ void can_lld_start(CANDriver *canp) {
   }

 #endif

 

-  /* Entering initialization mode. */

-  canp->state = CAN_STARTING;

+  /* Configuring CAN. */

   canp->can->MCR = CAN_MCR_INRQ;

   while ((canp->can->MSR & CAN_MSR_INAK) == 0)

     osalThreadSleepS(1);

-  /* BTR initialization.*/

   canp->can->BTR = canp->config->btr;

-  /* MCR initialization.*/

   canp->can->MCR = canp->config->mcr;

 

   /* Interrupt sources initialization.*/

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();