Changeset 0130f653 in rtems

Timestamp:

Sep 13, 2005, 1:13:34 PM (15 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

4a243b5

Parents:

b5496de

Message:

2005-09-12 Thomas Doerfler <Thomas.Doerfler@…>

PR 527/bsps
PR 822/bsps

• mpc8xx/clock/clock.c: Currently the MBX8xx BSP does not boot, because some logical errors are in the startup code. Additionally, the mpc8xx shared clock driver does not support the clocking scheme of some of the board variants, which are clocked from a 32768Hz (!) external crystal.

Location:

c/src/lib/libcpu/powerpc

Files:

• ChangeLog (modified) (1 diff)
• mpc8xx/clock/clock.c (modified) (1 diff)

c/src/lib/libcpu/powerpc/ChangeLog

@@ +1 @@
+2005-09-12      Thomas Doerfler <Thomas.Doerfler@imd-systems.de>
+
+        PR 527/bsps
+        PR 822/bsps
+        * mpc8xx/clock/clock.c: Currently the MBX8xx BSP does not boot,
+        because some logical errors are in the startup code. Additionally,
+        the mpc8xx shared clock driver does not support the clocking scheme
+        of some of the board variants, which are clocked from a 32768Hz (!)
+        external crystal.
+
 2005-08-12      Phil Torre <ptorre@zetron.com>
 

c/src/lib/libcpu/powerpc/mpc8xx/clock/clock.c

@@ -72 +72 @@
   unsigned desiredLevel;
   uint32_t   pit_value;
-  
-  pit_value = (rtems_configuration_get_microseconds_per_tick() *
-               rtems_cpu_configuration_get_clicks_per_usec()) - 1 ;
-  
+  rtems_unsigned32 mf_value;
+  rtems_unsigned32 extclk_value;
+  rtems_boolean force_prescaler = FALSE;
+  if (rtems_cpu_configuration_get_clicks_per_usec() == 0) {
+    /*
+     * oscclk is too low for PIT, compute extclk and derive PIT from there
+     */
+    mf_value  = m8xx.plprcr >> 20;    
+    pit_value = (_CPU_Table.clock_speed
+                 / (mf_value+1) 
+                 / 1000
+                 / 4
+                 * rtems_configuration_get_microseconds_per_tick()
+                 / 1000);
+    m8xx.sccr |=  (1<<23);
+    force_prescaler = TRUE;
+  }
+  else {
+    pit_value = (rtems_configuration_get_microseconds_per_tick() *
+                 rtems_cpu_configuration_get_clicks_per_usec());
+  
+    m8xx.sccr &= ~(1<<23);
+  }
+if ((pit_value > 0xffff) || force_prescaler){
+    /*
+     * try to activate prescaler
+     * NOTE: divider generates odd values now...
+     */
+    pit_value = pit_value / 128;
+    m8xx.sccr |= (1<<24);
+  }
+  else {
+    m8xx.sccr &= ~(1<<24);
+  }
+
   if (pit_value > 0xffff) {           /* pit is only 16 bits long */
     rtems_fatal_error_occurred(-1);
   }
-  m8xx.sccr &= ~(1<<24);
-  m8xx.pitc = pit_value;
+  m8xx.pitc = pit_value - 1;
 
   desiredLevel = BSP_get_clock_irq_level();