Implemented exceptions and timer management functions to remove dependencies from newlib

c/src/lib/libbsp/patmos/pasim/clock/ckinit.c

@@ -22,10 +22,6 @@
 #include <rtems.h>
 #include <bsp.h>
 
-#include <machine/patmos.h>
-#include <machine/exceptions.h>
-#include <machine/rtc.h>
-
 void Clock_exit( void );
 rtems_isr Clock_isr( rtems_vector_number vector )__attribute__((naked));
 
@@ -52,10 +48,9 @@ uint32_t         Clock_isrs;              /* ISRs until next tick */
 
 rtems_device_major_number rtems_clock_major = ~0;
 rtems_device_minor_number rtems_clock_minor;
-/* cycles from RTEMS start to Install_clock routine */
-uint64_t cycles_offset;
-/* CPU frequency in MHZ */
-uint32_t freq;
+
+/* usecs from RTEMS start to Install_clock routine */
+uint64_t usecs_bias;
 /* timestamp of the last tick in usec */
 uint64_t usec_offset;
 
@@ -67,6 +62,36 @@ rtems_isr_entry  Old_ticker;
 
 void Clock_exit( void );
 
+/*
+ * Get the current RTC microsecond value
+ */
+uint64_t get_cpu_usecs(void) {
+  unsigned ulo, uhi;
+
+  _iodev_ptr_t hi_usec = (_iodev_ptr_t)(__PATMOS_RTC_TIME_UP_ADDR);
+  _iodev_ptr_t lo_usec = (_iodev_ptr_t)(__PATMOS_RTC_TIME_LOW_ADDR);
+
+  // Order is important here
+  ulo = *lo_usec;
+  uhi = *hi_usec;
+
+  return (((unsigned long long) uhi) << 32) | ulo;
+}
+
+/*
+ * Set the timeout for the clock timer. The RTC will trigger an interrupt once
+ * the cycle counter reaches the given value.
+ */
+static inline void arm_usec_timer(uint64_t timestamp) {
+
+  _iodev_ptr_t hi_usec = (_iodev_ptr_t)(__PATMOS_RTC_TIME_UP_ADDR);
+  _iodev_ptr_t lo_usec = (_iodev_ptr_t)(__PATMOS_RTC_TIME_LOW_ADDR);
+
+  // Order is important here
+  *lo_usec = (unsigned)timestamp;
+  *hi_usec = (unsigned)(timestamp>>32);
+}
+
 void set_usec_timer (uint64_t time_warp)
 {
 
@@ -78,21 +103,9 @@ void set_usec_timer (uint64_t time_warp)
 	arm_usec_timer(usec_offset);
 }
 
-uint32_t get_cpu_freq_mhz(void)
-{
-	return get_cpu_freq()/1000000;
-}
-
 uint32_t bsp_clock_nanoseconds_since_last_tick(void)
 {
-	/*uint64_t volatile cycles_since_first_tick = (uint64_t)Clock_driver_ticks*rtems_configuration_get_microseconds_per_tick()*freq;
-	uint64_t volatile cycles_since_program_start = get_cpu_cycles();
-	uint64_t volatile cycles_since_last_tick = cycles_since_program_start - cycles_since_first_tick - cycles_offset;
-	uint64_t volatile microseconds_since_last_tick = cycles_since_last_tick*1000;
-	uint64_t nsecs = microseconds_since_last_tick / ((uint64_t)freq);*/
-
-	uint64_t nsecs = ((get_cpu_cycles() - ((uint64_t)Clock_driver_ticks*rtems_configuration_get_microseconds_per_tick()*freq) - cycles_offset)
-				* 1000) / ((uint64_t)freq);
+	uint64_t nsecs = (get_cpu_usecs() - usecs_bias - Clock_driver_ticks*rtems_configuration_get_microseconds_per_tick())*1000;
 
 	return (uint32_t) nsecs;
 }
@@ -324,13 +337,14 @@ void Install_clock(
 	Clock_driver_ticks = 0;
 	Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
 
-	exc_register(EXC_INTR_USEC, (uint32_t)clock_isr);
+	// set the isr routine
+	set_exc_handler(EXC_INTR_USEC, (uint32_t)clock_isr);
 	// clear pending flags
 	intr_clear_all_pending();
 	// unmask interrupt
 	intr_unmask(EXC_INTR_USEC);
 	// enable interrupts
-	intr_enable();
+	patmos_enable_interrupts();
 
 #if defined(Clock_driver_nanoseconds_since_last_tick)
 	rtems_clock_set_nanoseconds_extension(
@@ -338,19 +352,15 @@ void Install_clock(
 	);
 #endif
 
-	freq = get_cpu_freq_mhz();
-
 	/*
-	 * reset the cpu_cycles count to determine clock_nanoseconds_since_last_tick
+	 * reset the cpu_usecs count to determine clock_nanoseconds_since_last_tick
 	 */
-	cycles_offset = get_cpu_cycles();
+	usecs_bias = get_cpu_usecs();
 
 	usec_offset = get_cpu_usecs();	
 
 	set_usec_timer(rtems_configuration_get_microseconds_per_tick());
 
-
-
 	/*
 	 *  Schedule the clock cleanup routine to execute if the application exits.
 	 */

c/src/lib/libbsp/patmos/pasim/include/pasim.h

@@ -118,6 +118,8 @@ extern char _uart_base; /* linker symbol giving the address of the UART */
 
 extern char _timer_base; /* linker symbol giving the address of the RTC */
 
+extern uint64_t get_cpu_usecs (void);
+
 extern void set_usec_timer (uint64_t time_warp);
 
 /* Address to access the cycle counter low register of the RTC */

c/src/lib/libbsp/patmos/pasim/timer/timer.c

@@ -18,8 +18,6 @@
 
 #include <bsp.h>
 
-#include <machine/rtc.h>
-
 bool benchmark_timer_find_average_overhead;
 
 #define AVG_OVERHEAD      0  /* It typically takes 0 microseconds */
@@ -33,7 +31,7 @@ void benchmark_timer_initialize(void)
 	/*
 	 *  Timer runs long and accurate enough not to require an interrupt.
 	 */
-	timer_offset = get_cpu_cycles();
+	timer_offset = get_cpu_usecs();
 }
 
 int benchmark_timer_read(void)
@@ -44,7 +42,7 @@ int benchmark_timer_read(void)
 	 *  Read the timer and see how many clicks it has been since we started.
 	 */
 
-	total = (get_cpu_cycles() - timer_offset)/get_cpu_freq_mhz();
+	total = get_cpu_usecs() - timer_offset;
 
 	if ( benchmark_timer_find_average_overhead == true )
 		return total;          /* in one microsecond units */

c/src/lib/libcpu/patmos/exceptions/exceptions.c

@@ -20,6 +20,8 @@
 #include <rtems.h>
 #include <bsp.h>
 
+#include "exceptions.h"
+
 /*
  * Enable interrupts
  */
@@ -33,3 +35,27 @@ void patmos_enable_interrupts(void){
 void patmos_disable_interrupts(void){
   EXC_STATUS &= ~1;
 }
+
+/*
+ * Register a function as exception handler.
+ *   n - The exception to register the function for
+ *   fun - The exception handler
+ */
+void set_exc_handler(unsigned n, exc_handler_t fun){
+  EXC_VEC(n) = (unsigned)fun;
+}
+
+/*
+ * Clear the pending flag of all interrupts
+ */
+void intr_clear_all_pending(void){
+  EXC_PEND = 0;
+}
+
+/*
+ * Unmask a particular interrupts
+ * 	 n - The interrupt to be unmasked
+ */
+void intr_unmask(unsigned n){
+  EXC_MASK |= (1 << n);
+}

c/src/lib/libcpu/patmos/exceptions/exceptions.h

@@ -14,10 +14,34 @@
 #ifndef __PATMOS_EXCEPTIONS_h
 #define __PATMOS_EXCEPTIONS_h
 
+/*
+ * The exception handler type
+ */
+typedef void (*exc_handler_t)(void);
+
+/*
+ * The exception vector array
+ */
+#define EXC_VEC(I) (((_IODEV exc_handler_t volatile * const)(&_excunit_base+0x80))[I])
+
+/*
+ * Various named exception vector entry numbers
+ */
+#define EXC_ILLEGAL_OP       0
+#define EXC_ILLEGAL_ADDRESS  1
+#define EXC_INTR_CLOCK       16
+#define EXC_INTR_USEC        17
+
 void patmos_enable_interrupts(void);
 
 void patmos_disable_interrupts(void);
 
+void set_exc_handler(unsigned n, exc_handler_t fun);
+
+void intr_clear_all_pending(void);
+
+void intr_unmask(unsigned n);
+
 #endif
 
 /* end of include file */