Merge pull request cnlohr#837 from cnlohr/add_safe_timer_64_functions

Add 64-bit safe timer functions for 32- and 64-bit timers

Author: cnlohr

ch32fun/ch32fun.c

@@ -1868,6 +1868,45 @@ void DelaySysTick( uint32_t n )
 #endif
 }
 
+
+// Computes a 64-bit SysTick timestamp from the current CPU.
+// If the CPU supports a 64-bit SysTick, then it will make sure it
+// did not race condition.  If it's a 32-bit SysTick, a virtual
+// high word will be generated and incremented any time a wraparound
+// is detected. 
+//
+// In general, please do not use this function.  In 99% of cases, using 32-bit
+// functions with proper rollover is better. For instance you can use
+// TimeElapsed32( start, end ).
+//
+// This should only be used when you must act on time periods exceeding 2^31
+// ticks.
+//
+uint64_t funSysTick64( void )
+{
+	uint32_t base = funSysTick32();
+#ifdef funSysTickHigh
+
+	uint32_t high = funSysTickHigh();
+	uint32_t check = funSysTick32();
+
+	// If and only if check is higher than base can we guarantee high is
+	// valid and matches the check.
+	if( check >= base )
+		return ((uint64_t)high<<32) | check;
+
+	// Else we need a new high.
+	return (((uint64_t)(funSysTickHigh()))<<32) | check;
+#else
+	static uint32_t lastBase;
+	static uint32_t high;
+	if( base < lastBase ) { printf( "Trigger\n" );high++; }
+	lastBase = base;
+printf( "%d %d\n", lastBase, high );
+	return ((uint64_t)high<<32) | base;
+#endif
+}
+
 #if defined(CH32H41x)
 void StartV5F(v5f_main function)
 {

ch32fun/ch32fun.h

@@ -24,7 +24,11 @@
 	4. Delays
 		Delay_Us(n)
 		Delay_Ms(n)
-		DelaySysTick( uint32_t n );
+		DelaySysTick( uint32_t n )
+		TimeElapsed32( uint32_t now, uint32_t start);
+		TimeElapsed32U( now, start ); // For if events could be in the future.
+		funSysTick32()
+		funSysTick64()
 
 	5. printf
 		printf, _write may be semihosted, or printed to UART.
@@ -889,7 +893,20 @@ extern "C" {
 #define Ticks_from_Us(n)	((n) * DELAY_US_TIME)
 #define Ticks_from_Ms(n)	((n) * DELAY_MS_TIME)
 
-#define TimeElapsed32(now,start)  ((uint32_t)((uint32_t)(now)-(uint32_t)(start)))
+#define TimeElapsed32(now,start)  ((int32_t)((uint32_t)(now)-(uint32_t)(start)))
+#define TimeElapsed32u(now,start)  ((uint32_t)((uint32_t)(now)-(uint32_t)(start)))
+
+// #define funSysTick32() is defined per-architecture.
+
+// Get a 64-bit timestamp.  Please in general try to use 32-bit timestamps
+// whenever possible.  Use functions that automatically handle rollover
+// correctly like TimeElapsed32( start, end ).  Only use this in cases where
+// you must act on time periods exceeding 2^31 ticks.
+//
+// Also, if you are on a platform without a hardware 64-bit timer, you must
+// call this function at least once every 2^32 ticks to make sure MSBs aren't
+// lost.
+uint64_t funSysTick64( void );
 
 // Add a certain number of nops.  Note: These are usually executed in pairs
 // and take two cycles, so you typically would use 0, 2, 4, etc.
@@ -1010,7 +1027,6 @@ RV_STATIC_INLINE void funPinAF(u32 pin, u32 af)
 
 #if defined(__riscv) || defined(__riscv__) || defined( CH32V003FUN_BASE )
 
-
 // Stuff that can only be compiled on device (not for the programmer, or other host programs)
 
 // Initialize the ADC calibrate it and set some sane defaults.

ch32fun/ch32h41xhw.h

@@ -299,18 +299,31 @@ typedef enum IRQn
 
 #define DEFAULT_INTERRUPT_VECTOR_CONTENTS BASE_VECTOR "\n.option pop;\n"
 
-
-
 /* memory mapped structure for SysTick */
 typedef struct
 {
 	__IO uint32_t CTLR;
 	__IO uint32_t SR;
-	__IO uint64_t CNT;
-	uint32_t RESERVED0;
-	__IO uint64_t CMP;
+	union
+	{
+		struct
+		{
+			__IO uint32_t CNTL;
+			__IO uint32_t CNTH;
+			__IO uint32_t CMPL;
+			__IO uint32_t CMPH;
+		};
+		struct
+		{
+			__IO uint64_t CNT;
+			__IO uint64_t CMP;
+		};
+	};
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNTL)
+#define funSysTickHigh() (SysTick->CNTH)
+
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32l103hw.h

@@ -165,6 +165,7 @@ typedef struct
 	__IO uint64_t CMP;
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNT)
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32v003hw.h

@@ -101,6 +101,7 @@ typedef struct
     uint32_t RESERVED1;
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNT)
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32v10xhw.h

@@ -168,6 +168,9 @@ typedef struct __attribute__((packed))
   };
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNTL)
+#define funSysTickHigh() (SysTick->CNTH)
+
 #endif /* __ASSEMBLER__*/
 
 #define HardFault_IRQn    EXC_IRQn

ch32fun/ch32v20xhw.h

@@ -200,6 +200,7 @@ typedef struct
 	__IO uint64_t CMP;
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNT)
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32v30xhw.h

@@ -260,6 +260,7 @@ typedef struct
 	__IO uint64_t CMP;
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNT)
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32x00xhw.h

@@ -109,6 +109,7 @@ typedef struct
     uint32_t RESERVED1;
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNT)
 
 #endif /* __ASSEMBLER__*/
 

ch32fun/ch32x03xhw.h

@@ -149,6 +149,8 @@ typedef struct
   };
 } SysTick_Type;
 
+#define funSysTick32() (SysTick->CNTL)
+#define funSysTickHigh() (SysTick->CNTH)
 
 #endif /* __ASSEMBLER__*/