From 1437e590d75a23b57a5d613bf037bb1f07d082d5 Mon Sep 17 00:00:00 2001
From: utzig <utzig@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Sat, 26 Jul 2014 13:26:47 +0000
Subject: [PATCH] [AVR] Add preliminary tickless support to HAL

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7101 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/ports/AVR/avr_timers.h |   7 ++
 os/hal/ports/AVR/hal_lld.c    |  48 -----------
 os/hal/ports/AVR/hal_lld.h    |  45 ----------
 os/hal/ports/AVR/st_lld.c     | 155 ++++++++++++++++++++++++++++++++++
 os/hal/ports/AVR/st_lld.h     |  29 +++++--
 5 files changed, 186 insertions(+), 98 deletions(-)

diff --git a/os/hal/ports/AVR/avr_timers.h b/os/hal/ports/AVR/avr_timers.h
index 26b891937..b0a137ddd 100644
--- a/os/hal/ports/AVR/avr_timers.h
+++ b/os/hal/ports/AVR/avr_timers.h
@@ -17,6 +17,13 @@
 #ifndef _AVR_TIMERS_H_
 #define _AVR_TIMERS_H_
 
+#include "mcuconf.h"
+
+#if ((NIL_CFG_ST_TIMEDELTA > 0 || CH_CFG_ST_TIMEDELTA > 0) && \
+     (AVR_GPT_USE_TIM1 || AVR_PWM_USE_TIM1 || AVR_ICU_USE_TIM1))
+  #error "Timer 1 cannot be used by drivers when running in tickless mode."
+#endif
+
 #if ((AVR_GPT_USE_TIM1 && AVR_PWM_USE_TIM1) || \
      (AVR_GPT_USE_TIM1 && AVR_ICU_USE_TIM1) || \
      (AVR_PWM_USE_TIM1 && AVR_ICU_USE_TIM1))
diff --git a/os/hal/ports/AVR/hal_lld.c b/os/hal/ports/AVR/hal_lld.c
index 894d5dcc5..c3b90dd6b 100644
--- a/os/hal/ports/AVR/hal_lld.c
+++ b/os/hal/ports/AVR/hal_lld.c
@@ -40,21 +40,6 @@
 /* Driver interrupt handlers.                                                */
 /*===========================================================================*/
 
-/**
- * @brief   Timer0 interrupt handler.
- */
-OSAL_IRQ_HANDLER(AVR_TIMER_VECT) {
-
-  OSAL_IRQ_PROLOGUE();
-
-  osalSysLockFromISR();
-  osalOsTimerHandlerI();
-  osalSysUnlockFromISR();
-
-  OSAL_IRQ_EPILOGUE();
-}
-
-
 /*===========================================================================*/
 /* Driver exported functions.                                                */
 /*===========================================================================*/
@@ -65,39 +50,6 @@ OSAL_IRQ_HANDLER(AVR_TIMER_VECT) {
  * @notapi
  */
 void hal_lld_init(void) {
-
-  /*
-   * Timer 0 setup.
-   */
-#if defined(TCCR0B) /* Timer has multiple output comparators                       */
-  TCCR0A  = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
-            (0 << COM0A1) | (0 << COM0A0) |              /* OC0A disabled.   */
-            (0 << COM0B1) | (0 << COM0B0);               /* OC0B disabled.   */
-  TCCR0B  = (0 << WGM02) | AVR_TIMER_PRESCALER_BITS;     /* CTC mode.        */
-  OCR0A   = AVR_TIMER_COUNTER - 1;
-  TCNT0   = 0;                                           /* Reset counter.   */
-  TIFR0   = (1 << OCF0A);                                /* Reset pending.   */
-  TIMSK0  = (1 << OCIE0A);                               /* IRQ on compare.  */
-
-#elif defined(TCCR0A) /* AT90CAN doesn't have TCCR0B and slightly different TCCR0A */
-  TCCR0A  = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
-            (0 << COM0A1) | (0 << COM0A0);               /* OC0A disabled.   */
-  OCR0A   = AVR_TIMER_COUNTER - 1;
-  TCNT0   = 0;                                           /* Reset counter.   */
-  TIFR0   = (1 << OCF0A);                                /* Reset pending.   */
-  TIMSK0  = (1 << OCIE0A);                               /* IRQ on compare.  */
-
-#elif defined(TCCR0) /* Timer has single output comparator                   */
-  TCCR0   = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
-            (0 << COM01) | (0 << COM00) |                /* OC0A disabled.   */
-            AVR_TIMER_PRESCALER_BITS;
-  OCR0    = AVR_TIMER_COUNTER - 1;
-  TCNT0   = 0;                                           /* Reset counter.   */
-  TIFR    = (1 << OCF0);                                 /* Reset pending.   */
-  TIMSK   = (1 << OCIE0);                                /* IRQ on compare.  */
-#else
-  #error "Neither TCCR0A nor TCCR0 registers are defined"
-#endif
 }
 
 /** @} */
diff --git a/os/hal/ports/AVR/hal_lld.h b/os/hal/ports/AVR/hal_lld.h
index c72063ac0..5685943f3 100644
--- a/os/hal/ports/AVR/hal_lld.h
+++ b/os/hal/ports/AVR/hal_lld.h
@@ -39,59 +39,14 @@
  */
 #define PLATFORM_NAME "AVR"
 
-/**
- * @brief  Timer maximum value 
- */
-#define AVR_TIMER_COUNTER_MAX 255
-
 /*===========================================================================*/
 /* Driver pre-compile time settings.                                         */
 /*===========================================================================*/
 
-/* Work out what the timer interrupt is called on this MCU */
-#ifdef TIMER0_COMPA_vect
-  #define AVR_TIMER_VECT TIMER0_COMPA_vect
-#elif defined(TIMER_COMPA_vect)
-  #define AVR_TIMER_VECT TIMER_COMPA_vect
-#elif defined(TIMER0_COMP_vect)
-  #define AVR_TIMER_VECT TIMER0_COMP_vect
-#else
-  #error "Cannot find interrupt vector name for timer"
-#endif
-
 /*===========================================================================*/
 /* Derived constants and error checks.                                       */
 /*===========================================================================*/
 
-/* Find the most suitable prescaler setting for the desired OSAL_ST_FREQUENCY */
-#if ((F_CPU / OSAL_ST_FREQUENCY) <= AVR_TIMER_COUNTER_MAX)
-  #define AVR_TIMER_PRESCALER 1
-  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(0<<CS01)|(1<<CS00); /* CLK      */
-#elif ((F_CPU / OSAL_ST_FREQUENCY / 8) <= AVR_TIMER_COUNTER_MAX)
-  #define AVR_TIMER_PRESCALER 8
-  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(1<<CS01)|(0<<CS00); /* CLK/8    */
-#elif ((F_CPU / OSAL_ST_FREQUENCY / 64) <= AVR_TIMER_COUNTER_MAX)
-  #define AVR_TIMER_PRESCALER 64
-  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(1<<CS01)|(1<<CS00); /* CLK/64   */
-#elif ((F_CPU / OSAL_ST_FREQUENCY / 256) <= AVR_TIMER_COUNTER_MAX)
-  #define AVR_TIMER_PRESCALER 256
-  #define AVR_TIMER_PRESCALER_BITS (1<<CS02)|(0<<CS01)|(0<<CS00); /* CLK/256  */
-#elif ((F_CPU / OSAL_ST_FREQUENCY / 1024) <= AVR_TIMER_COUNTER_MAX)
-  #define AVR_TIMER_PRESCALER 1024
-  #define AVR_TIMER_PRESCALER_BITS (1<<CS02)|(0<<CS01)|(1<<CS00); /* CLK/1024 */
-#else
-  #error "Frequency too low for timer, please set OSAL_ST_FREQUENCY to a higher value"
-#endif
-
-#define AVR_TIMER_COUNTER (F_CPU / OSAL_ST_FREQUENCY / AVR_TIMER_PRESCALER)
-
-/* Test if OSAL_ST_FREQUENCY can be matched exactly using this timer */
-#define F_CPU_ (AVR_TIMER_COUNTER * AVR_TIMER_PRESCALER * OSAL_ST_FREQUENCY)
-#if (F_CPU_ != F_CPU)
-  #warning "OSAL_ST_FREQUENCY cannot be generated exactly using timer"
-#endif
-#undef F_CPU_
-
 /*===========================================================================*/
 /* Driver data structures and types.                                         */
 /*===========================================================================*/
diff --git a/os/hal/ports/AVR/st_lld.c b/os/hal/ports/AVR/st_lld.c
index 463ff8b8a..349d7307e 100644
--- a/os/hal/ports/AVR/st_lld.c
+++ b/os/hal/ports/AVR/st_lld.c
@@ -30,6 +30,11 @@
 /* Driver local definitions.                                                 */
 /*===========================================================================*/
 
+/**
+ * @brief  Timer maximum value
+ */
+#define AVR_TIMER_COUNTER_MAX 255
+
 /*===========================================================================*/
 /* Driver exported variables.                                                */
 /*===========================================================================*/
@@ -42,6 +47,60 @@
 /* Driver local variables and types.                                         */
 /*===========================================================================*/
 
+#if (OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC) || defined(__DOXYGEN__)
+
+/* Work out what the timer interrupt is called on this MCU */
+#ifdef TIMER0_COMPA_vect
+  #define AVR_TIMER_VECT TIMER0_COMPA_vect
+#elif defined(TIMER_COMPA_vect)
+  #define AVR_TIMER_VECT TIMER_COMPA_vect
+#elif defined(TIMER0_COMP_vect)
+  #define AVR_TIMER_VECT TIMER0_COMP_vect
+#else
+  #error "Cannot find interrupt vector name for timer"
+#endif
+
+/* Find the most suitable prescaler setting for the desired OSAL_ST_FREQUENCY */
+#if ((F_CPU / OSAL_ST_FREQUENCY) <= AVR_TIMER_COUNTER_MAX)
+  #define AVR_TIMER_PRESCALER 1
+  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(0<<CS01)|(1<<CS00); /* CLK      */
+#elif ((F_CPU / OSAL_ST_FREQUENCY / 8) <= AVR_TIMER_COUNTER_MAX)
+  #define AVR_TIMER_PRESCALER 8
+  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(1<<CS01)|(0<<CS00); /* CLK/8    */
+#elif ((F_CPU / OSAL_ST_FREQUENCY / 64) <= AVR_TIMER_COUNTER_MAX)
+  #define AVR_TIMER_PRESCALER 64
+  #define AVR_TIMER_PRESCALER_BITS (0<<CS02)|(1<<CS01)|(1<<CS00); /* CLK/64   */
+#elif ((F_CPU / OSAL_ST_FREQUENCY / 256) <= AVR_TIMER_COUNTER_MAX)
+  #define AVR_TIMER_PRESCALER 256
+  #define AVR_TIMER_PRESCALER_BITS (1<<CS02)|(0<<CS01)|(0<<CS00); /* CLK/256  */
+#elif ((F_CPU / OSAL_ST_FREQUENCY / 1024) <= AVR_TIMER_COUNTER_MAX)
+  #define AVR_TIMER_PRESCALER 1024
+  #define AVR_TIMER_PRESCALER_BITS (1<<CS02)|(0<<CS01)|(1<<CS00); /* CLK/1024 */
+#else
+  #error "Frequency too low for timer, please set OSAL_ST_FREQUENCY to a higher value"
+#endif
+
+#define AVR_TIMER_COUNTER (F_CPU / OSAL_ST_FREQUENCY / AVR_TIMER_PRESCALER)
+
+/* Test if OSAL_ST_FREQUENCY can be matched exactly using this timer */
+#define F_CPU_ (AVR_TIMER_COUNTER * AVR_TIMER_PRESCALER * OSAL_ST_FREQUENCY)
+#if (F_CPU_ != F_CPU)
+  #warning "OSAL_ST_FREQUENCY cannot be generated exactly using timer"
+#endif
+#undef F_CPU_
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC */
+
+#if (OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING) || defined(__DOXYGEN__)
+
+/* FIXME: Prescaler is now fixed in 1024.
+ *        Should add support for calculating best value according to
+ *        user requested configuration.
+ */
+#define PRESCALER (_BV(CS12) | _BV(CS10))
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING */
+
 /*===========================================================================*/
 /* Driver local functions.                                                   */
 /*===========================================================================*/
@@ -50,6 +109,44 @@
 /* Driver interrupt handlers.                                                */
 /*===========================================================================*/
 
+#if (OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC) || defined(__DOXYGEN__)
+
+/**
+ * @brief Timer handler for periodic mode.
+ */
+OSAL_IRQ_HANDLER(AVR_TIMER_VECT) {
+
+  OSAL_IRQ_PROLOGUE();
+
+  osalSysLockFromISR();
+  osalOsTimerHandlerI();
+  osalSysUnlockFromISR();
+
+  OSAL_IRQ_EPILOGUE();
+}
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC */
+
+#if (OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING) || defined(__DOXYGEN__)
+
+/**
+ * @brief Timer handler for free running mode.
+ */
+OSAL_IRQ_HANDLER(TIMER1_COMPA_vect) {
+
+  OSAL_IRQ_PROLOGUE();
+
+  // TODO: reset status if required
+
+  osalSysLockFromISR();
+  osalOsTimerHandlerI();
+  osalSysUnlockFromISR();
+
+  OSAL_IRQ_EPILOGUE();
+}
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING */
+
 /*===========================================================================*/
 /* Driver exported functions.                                                */
 /*===========================================================================*/
@@ -60,6 +157,64 @@
  * @notapi
  */
 void st_lld_init(void) {
+
+#if (OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING) || defined(__DOXYGEN__)
+
+  /*
+   * Periodic mode uses Timer 1 (16 bit).
+   */
+
+  /* CTC mode, no clock source */
+  TCCR1A  = 0;
+  TCCR1B  = _BV(WGM12);
+
+  /* start disabled */
+  TCCR1C  = 0;
+  OCR1A   = 0;
+  TCNT1   = 0;
+  TIFR1   = _BV(OCF1A);                                  /* Reset pending.   */
+  TIMSK1  = 0;
+  TCCR1B  = PRESCALER;
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING */
+
+#if (OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC) || defined(__DOXYGEN__)
+
+  /*
+   * Periodic mode uses Timer 0 (8 bit).
+   */
+#if defined(TCCR0B) /* Timer has multiple output comparators                       */
+  TCCR0A  = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
+            (0 << COM0A1) | (0 << COM0A0) |              /* OC0A disabled.   */
+            (0 << COM0B1) | (0 << COM0B0);               /* OC0B disabled.   */
+  TCCR0B  = (0 << WGM02) | AVR_TIMER_PRESCALER_BITS;     /* CTC mode.        */
+  OCR0A   = AVR_TIMER_COUNTER - 1;
+  TCNT0   = 0;                                           /* Reset counter.   */
+  TIFR0   = (1 << OCF0A);                                /* Reset pending.   */
+  TIMSK0  = (1 << OCIE0A);                               /* IRQ on compare.  */
+
+#elif defined(TCCR0A) /* AT90CAN doesn't have TCCR0B and slightly different TCCR0A */
+  TCCR0A  = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
+            (0 << COM0A1) | (0 << COM0A0);               /* OC0A disabled.   */
+  OCR0A   = AVR_TIMER_COUNTER - 1;
+  TCNT0   = 0;                                           /* Reset counter.   */
+  TIFR0   = (1 << OCF0A);                                /* Reset pending.   */
+  TIMSK0  = (1 << OCIE0A);                               /* IRQ on compare.  */
+
+#elif defined(TCCR0) /* Timer has single output comparator                   */
+  TCCR0   = (1 << WGM01) | (0 << WGM00) |                /* CTC mode.        */
+            (0 << COM01) | (0 << COM00) |                /* OC0A disabled.   */
+            AVR_TIMER_PRESCALER_BITS;
+  OCR0    = AVR_TIMER_COUNTER - 1;
+  TCNT0   = 0;                                           /* Reset counter.   */
+  TIFR    = (1 << OCF0);                                 /* Reset pending.   */
+  TIMSK   = (1 << OCIE0);                                /* IRQ on compare.  */
+#else
+  #error "Neither TCCR0A nor TCCR0 registers are defined"
+#endif
+
+#endif /* OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC */
+
 }
 
 #endif /* OSAL_ST_MODE != OSAL_ST_MODE_NONE */
diff --git a/os/hal/ports/AVR/st_lld.h b/os/hal/ports/AVR/st_lld.h
index 024135c8f..6b47596ba 100644
--- a/os/hal/ports/AVR/st_lld.h
+++ b/os/hal/ports/AVR/st_lld.h
@@ -27,6 +27,9 @@
 #ifndef _ST_LLD_H_
 #define _ST_LLD_H_
 
+#include "mcuconf.h"
+#include "avr_timers.h"
+
 /*===========================================================================*/
 /* Driver constants.                                                         */
 /*===========================================================================*/
@@ -35,10 +38,19 @@
 /* Driver pre-compile time settings.                                         */
 /*===========================================================================*/
 
+/*
+ * TODO: for models that have many timers,
+ *       could add AVR_ST_USE_TIMER
+ */
+
 /*===========================================================================*/
 /* Derived constants and error checks.                                       */
 /*===========================================================================*/
 
+/*
+ * TODO: error checks for valid timer selected
+ */
+
 /*===========================================================================*/
 /* Driver data structures and types.                                         */
 /*===========================================================================*/
@@ -72,7 +84,7 @@ extern "C" {
  */
 static inline systime_t st_lld_get_counter(void) {
 
-  return (systime_t)0;
+  return (systime_t) TCNT1;
 }
 
 /**
@@ -86,7 +98,13 @@ static inline systime_t st_lld_get_counter(void) {
  */
 static inline void st_lld_start_alarm(systime_t time) {
 
-  (void)time;
+  OCR1A = (uint16_t) time;
+
+  /* Reset pending. */
+  TIFR1 = _BV(OCF1A);
+
+  /* enable interrupt */
+  TIMSK1 = _BV(OCIE1A);
 }
 
 /**
@@ -96,6 +114,7 @@ static inline void st_lld_start_alarm(systime_t time) {
  */
 static inline void st_lld_stop_alarm(void) {
 
+  TIMSK1 = 0;
 }
 
 /**
@@ -107,7 +126,7 @@ static inline void st_lld_stop_alarm(void) {
  */
 static inline void st_lld_set_alarm(systime_t time) {
 
-  (void)time;
+  OCR1A = (uint16_t) time;
 }
 
 /**
@@ -119,7 +138,7 @@ static inline void st_lld_set_alarm(systime_t time) {
  */
 static inline systime_t st_lld_get_alarm(void) {
 
-  return (systime_t)0;
+  return (systime_t) OCR1A;
 }
 
 /**
@@ -133,7 +152,7 @@ static inline systime_t st_lld_get_alarm(void) {
  */
 static inline bool st_lld_is_alarm_active(void) {
 
-  return false;
+  return (bool) ((TIMSK1 & _BV(OCIE1A)) != 0);
 }
 
 #endif /* _ST_LLD_H_ */