Improved parameter checks for bit rate function.

c/src/lib/libbsp/powerpc/gen5200/ChangeLog

@@ -1,3 +1,8 @@
+2008-09-04	Sebastian Huber <sebastian.huber@embedded-brains.de>
+
+	* include/mscan-base.h, mscan/mscan-base.c, mscan/mscan.c,
+	mscan/mscan_int.h: Improved parameter checks for bit rate function.
+
 2008-09-03	Joel Sherrill <joel.sherrill@oarcorp.com>
 
 	* Makefile.am, bestcomm/load_task.c,

c/src/lib/libbsp/powerpc/gen5200/include/mscan-base.h

@@ -31,7 +31,11 @@
  * @{
  */
 
-#define MSCAN_BIT_RATE_DEFAULT 100000
+#define MSCAN_BIT_RATE_MIN 10000
+
+#define MSCAN_BIT_RATE_MAX 1000000
+
+#define MSCAN_BIT_RATE_DEFAULT 125000
 
 #define MSCAN_FILTER_NUMBER_MIN 0
 
@@ -231,13 +235,13 @@ typedef struct {
   uint8_t tier;
 } mscan_context;
 
-void mscan_enable( mscan *m, unsigned bit_rate);
+bool mscan_enable( mscan *m, unsigned bit_rate);
 
 void mscan_disable( mscan *m);
 
 void mscan_interrupts_disable( mscan *m);
 
-void mscan_set_bit_rate( mscan *m, unsigned bit_rate);
+bool mscan_set_bit_rate( mscan *m, unsigned bit_rate);
 
 void mscan_initialization_mode_enter( mscan *m, mscan_context *context);
 

c/src/lib/libbsp/powerpc/gen5200/mscan/mscan-base.c

@@ -139,21 +139,33 @@ static uint8_t prescaler_calculation(
  * @brief Sets the bit rate for the MSCAN module @a m to @a can_bit_rate
  * in [bits/s].
  */
-void mscan_set_bit_rate( mscan *m, unsigned can_bit_rate)
+bool mscan_set_bit_rate( mscan *m, unsigned can_bit_rate)
 {
   mscan_context context;
-  uint32_t prescale_val = 0;
+  unsigned prescale_val = 0;
   uint8_t tq_no,
     tseg_1,
     tseg_2,
     sseg;
 
+  if (can_bit_rate < MSCAN_BIT_RATE_MIN || can_bit_rate > MSCAN_BIT_RATE_MAX) {
+    return false;
+  }
+
   /* Enter initialization mode */
   mscan_initialization_mode_enter( m, &context);
 
   /* get optimized prescaler value */
   prescale_val = prescaler_calculation(can_bit_rate, IPB_CLOCK, &tq_no);
 
+  /* Check prescaler value */
+  if (prescale_val > 64) {
+    /* Leave initialization mode */
+    mscan_initialization_mode_leave( m, &context);
+    
+    return false;
+  }
+
   /* get time segment length from time segment table */
   tseg_1 = can_time_segment_table[tq_no - MIN_NO_OF_TQ][TSEG_1];
   tseg_2 = can_time_segment_table[tq_no - MIN_NO_OF_TQ][TSEG_2];
@@ -185,6 +197,8 @@ void mscan_set_bit_rate( mscan *m, unsigned can_bit_rate)
 
   /* Leave initialization mode */
   mscan_initialization_mode_leave( m, &context);
+
+  return true;
 }
 
 /**
@@ -280,8 +294,10 @@ void mscan_sleep_mode_leave( mscan *m)
  *
  * The module is set to listen only mode.
  */
-void mscan_enable( mscan *m, unsigned bit_rate)
+bool mscan_enable( mscan *m, unsigned bit_rate)
 {
+  bool s = true;
+
   /* Disable the module */
   mscan_disable( m);
 
@@ -295,13 +311,15 @@ void mscan_enable( mscan *m, unsigned bit_rate)
   mscan_filter_clear( m);
 
   /* Set bit rate and leave initialization mode */
-  mscan_set_bit_rate( m, bit_rate);
+  s = mscan_set_bit_rate( m, bit_rate);
 
   /* Clear all flags */
   m->ctl0 = CTL0_RXFRM;
 
   /* Disable interrupts */
   mscan_interrupts_disable( m);
+
+  return s;
 }
 
 /**

c/src/lib/libbsp/powerpc/gen5200/mscan/mscan.c

@@ -495,7 +495,7 @@ void mpc5200_mscan_perform_initialization_mode_settings(mscan *m)
   mscan_context context;
 
   /* perform all can bit time settings */
-  mscan_set_bit_rate(m, CAN_BIT_RATE);
+  (void) mscan_set_bit_rate(m, MSCAN_BIT_RATE_DEFAULT);
 
   /* Enter initialization mode */
   mscan_initialization_mode_enter( m, &context);
@@ -1185,26 +1185,17 @@ rtems_device_driver mscan_control(rtems_device_major_number major,
 
       /* set can bitrate */
     case MSCAN_SET_BAUDRATE:
-
-      /* check bitrate settings */
-      if (((ctrl_parms->ctrl_can_bitrate) >= CAN_BIT_RATE_MIN)
-          && ((ctrl_parms->ctrl_can_bitrate) <= CAN_BIT_RATE_MAX)) {
-
-        /* perform all can bit time settings */
-        mscan_set_bit_rate(m, ctrl_parms->ctrl_can_bitrate);
-
-        /* enable ints. */
-        mscan_interrupts_enable(m);
-
-        /* wait for bus sync. */
-        mpc5200_mscan_wait_sync(m);
-
-        return RTEMS_SUCCESSFUL;
-      } else {
-
+      /* perform all can bit time settings */
+      if (!mscan_set_bit_rate(m, ctrl_parms->ctrl_can_bitrate)) {
         return RTEMS_UNSATISFIED;
       }
 
+      /* enable ints. */
+      mscan_interrupts_enable(m);
+
+      /* wait for bus sync. */
+      mpc5200_mscan_wait_sync(m);
+
       break;
 
     case SET_TX_BUF_NO:

c/src/lib/libbsp/powerpc/gen5200/mscan/mscan_int.h

@@ -39,10 +39,6 @@ extern "C" {
 #define MSCAN_NORMAL_MODE            4
 #define MSCAN_SLEEP_MODE             8
 
-#define CAN_BIT_RATE_MAX         1000000
-#define CAN_BIT_RATE_MIN         100000
-#define CAN_BIT_RATE             100000
-
 #define MSCAN_RX_BUFF_NOACTIVE   (0 << 4)
 #define MSCAN_RX_BUFF_EMPTY      (1 << 6)
 #define MSCAN_RX_BUFF_FULL       (1 << 5)