RT #72064. Added timer support to the stm3220g-eval port.

cpu/arm_cortexm3/stm32f2/timer.c

@@ -21,14 +21,26 @@
 
 #include <common.h>
 
+/* HCLK/8 */
+#define SYSTICK_FREQ	(clock_get(CLOCK_HCLK)/8)
+
+/* Internal tick units */
+static unsigned long long timestamp;	/* Monotonic incrementing timer */
+static ulong              lastdec;	/* Last decrementer snapshot */
+
 /*
  * Init timer.
  */
 int timer_init(void)
 {
-	/*
-	 * TBD
-	 */
+	volatile struct cm3_systick *systick =
+		(volatile struct cm3_systick *)CM3_SYSTICK_BASE;
+
+	systick->load = CM3_SYSTICK_LOAD_RELOAD_MSK - 1;
+	systick->val = 0;
+	/* Use external clock, no ints */
+	systick->ctrl = CM3_SYSTICK_CTRL_EN;
+	timestamp = 0;
 
 	return 0;
 }
@@ -38,11 +50,18 @@ int timer_init(void)
  */
 unsigned long get_timer(unsigned long base)
 {
-	/*
-	 * TBD
-	 */
+	volatile struct cm3_systick *systick =
+		(volatile struct cm3_systick *)CM3_SYSTICK_BASE;
+	ulong now = systick->val;
 
-	return 0;
+	if (lastdec >= now)
+		timestamp += lastdec - now;
+	else
+		timestamp += lastdec + CM3_SYSTICK_LOAD_RELOAD_MSK - 1 - now;
+
+	lastdec = now;
+
+	return timestamp / (SYSTICK_FREQ / 1000) - base;
 }
 
 /*
@@ -50,9 +69,10 @@ unsigned long get_timer(unsigned long base)
  */
 void reset_timer(void)
 {
-	/*
-	 * TBD
-	 */
+	volatile struct cm3_systick *systick =
+		(volatile struct cm3_systick *)(CM3_SYSTICK_BASE);
+	lastdec = systick->val;
+	timestamp = 0;
 }
 
 /*
@@ -60,9 +80,24 @@ void reset_timer(void)
  */
 void __udelay(unsigned long usec)
 {
-	/*
-	 * TBD
-	 */
+	ulong clc, tmp;
+	volatile struct cm3_systick *systick =
+		(volatile struct cm3_systick *)(CM3_SYSTICK_BASE);
+
+
+	clc = usec * (SYSTICK_FREQ / 1000000);
+
+	/* get current timestamp */
+	tmp = systick->val;
+
+	if (tmp < clc) {
+		/* loop till event */
+		while (systick->val < tmp ||
+			   systick->val > (CM3_SYSTICK_LOAD_RELOAD_MSK - 1 -
+				clc + tmp)) ;	/* nop */
+	} else {
+		while (systick->val > (tmp - clc)) ;
+	}
 }
 
 /*
@@ -71,9 +106,5 @@ void __udelay(unsigned long usec)
  */
 unsigned long get_tbclk(void)
 {
-	/*
-	 * TBD
-	 */
-
-	return 0;
+	return SYSTICK_FREQ;
 }