1 files changed, 43 insertions, 0 deletions
diff --git a/nuttx/arch/c5471/src/up_timerisr.c b/nuttx/arch/c5471/src/up_timerisr.c
index b636d1084..ab1155b71 100644
--- a/nuttx/arch/c5471/src/up_timerisr.c
+++ b/nuttx/arch/c5471/src/up_timerisr.c
@@ -41,7 +41,30 @@
 #include <sys/types.h>
 #include <debug.h>
 #include <nuttx/arch.h>
+#include "clock_internal.h"
 #include "up_internal.h"
+#include "c5471.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/* We want the general purpose timer running at the rate
+ * MSEC_PER_TICK. The C5471 clock is 47.5MHz and we're using
+ * a timer PTV value of 3 (3 == divide incoming frequency by
+ * 16) which then yields a 16 bitCLKS_PER_INT value
+ * of 29687.
+ *
+ *   47500000 / 16 = 2968750 clocks/sec
+ *   2968750 / 100 = 29687   clocks/ 100Hz interrupt
+ *
+ */
+
+#define CLKS_PER_INT       29687
+#define CLKS_PER_INT_SHIFT 5
+#define AR                 0x00000010
+#define ST                 0x00000008
+#define PTV                0x00000003
 
 /************************************************************
  * Private Types
@@ -91,3 +114,23 @@ int up_timerisr(int irq, uint32 *regs)
    current_regs = saved_regs;
    return 0;
 }
+
+void up_timerinit(void)
+{
+  uint32 val;
+
+  up_disable_irq(C5471_IRQ_SYSTIMER);
+
+  /* Start the general purpose timer running in auto-reload mode
+   * so that an interrupt is generated at the rate MSEC_PER_TICK.
+   */
+
+  val = ((CLKS_PER_INT-1) << CLKS_PER_INT_SHIFT) | AR | ST | PTV;
+  putreg32(val, C5471_TIMER2_CTRL);
+
+  /* Attach and enable the timer interrupt */
+
+  irq_attach(C5471_IRQ_SYSTIMER, (xcpt_t)up_timerisr);
+  up_enable_irq(C5471_IRQ_SYSTIMER);
+}
+