Merge pull request #4089 from dkm/pr/timer

Reworking timer in lm4f120, fix #4077

boards/ek-lm4f120xl/include/periph_conf.h

@@ -42,19 +42,26 @@ extern "C" {
  */
 #define TIMER_NUMOF         (2U)
 #define TIMER_0_EN          1
-#define TIMER_1_EN          0
+#define TIMER_1_EN          1
 #define TIMER_IRQ_PRIO      1
 
-/* Timer 0 configuration */
+/* Timer 0 configuration
+ *
+ * WTIMER0 is a 32/64bits timer.
+ * We use timer_a as TIMER_0
+ */
 #define TIMER_0_CHANNELS    1
-#define TIMER_0_PRESCALER   (39U)
 #define TIMER_0_MAX_VALUE   (0xffffffff)
 #define TIMER_0_ISR         isr_wtimer0a
 #define TIMER_0_IRQ_CHAN    Timer0A_IRQn
 
-/* Timer 1 configuration */
+/* Timer 1 configuration
+ *
+ * WTIMER1 is a 32/64bits timer.
+ * We use timer_a as TIMER_1
+ */
+
 #define TIMER_1_CHANNELS    1
-#define TIMER_1_PRESCALER   (39U)
 #define TIMER_1_MAX_VALUE   (0xffffffff)
 #define TIMER_1_ISR         isr_wtimer1a
 #define TIMER_1_IRQ_CHAN    Timer1A_IRQn

cpu/lm4f120/periph/timer.c

 /*
  * Copyright (C) 2015 Rakendra Thapa <rakendrathapa@gmail.com
+ *               2015 Marc Poulhiès <dkm@kataplop.net>
  *
  * This file is subject to the terms and conditions of the GNU Lesser General
  * Public License v2.1. See the file LICENSE in the top level directory for more
@@ -14,6 +15,7 @@
  * @brief       Implementation of the low-level timer driver for the LM4F120
  *
  * @author      Rakendra Thapa <rakendrathapa@gmail.com>
+ *              Marc Poulhiès <dkm@kataplop.net>
  */
 
 #include <stdint.h>
@@ -27,132 +29,363 @@
 
 #define ENABLE_DEBUG (0)
 #include "debug.h"
+
 /* guard file in case no timers are defined */
-#if TIMER_0_EN
+#if TIMER_NUMOF
 
 /**
  * @brief Struct holding the configuration data
  * @{
  */
 typedef struct {
-    void (*cb)(int);            /**< timeout callback */
+    void (*cb)(int);        /**< timeout callback */
+    unsigned int divisor;   /**< software clock divisor */
 } timer_conf_t;
 
 static timer_conf_t config[TIMER_NUMOF];
 /**@}*/
 
+#include "hw_timer.h"
+
+/* Missing from driverlib */
+static inline unsigned long
+PRIV_TimerPrescaleSnapshotGet(unsigned long ulbase, unsigned long ultimer) {
+    return((ultimer == TIMER_A) ? HWREG(ulbase + TIMER_O_TAPS) :
+           HWREG(ulbase + TIMER_O_TBPS));
+}
+
+static inline unsigned long long _scaled_to_ll_value(unsigned int uncorrected, unsigned int divisor)
+{
+    const unsigned long long scaledv = (unsigned long long) uncorrected * divisor;
+    return scaledv;
+}
+
+static inline unsigned int _llvalue_to_scaled_value(unsigned long long corrected, unsigned int divisor)
+{
+    const unsigned long long scaledv = corrected / divisor;
+    return scaledv;
+}
+
 int timer_init(tim_t dev, unsigned int us_per_tick, void (*callback)(int))
 {
-    if (dev == TIMER_0) {
-        config[dev].cb = callback;                          /* User Function */
-        ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_WTIMER0);  /* Activate Timer0 */
-        WTIMER0_CTL_R &= ~0x00000001;                       /* Disable timer0A during setup */
-        WTIMER0_CFG_R  = TIMER_CFG_16_BIT;
-        WTIMER0_TAMR_R = TIMER_TAMR_TAMR_PERIOD;            /* Configure for periodic mode */
-        WTIMER0_TAPR_R = TIMER_0_PRESCALER;                 /* 1us timer0A */
-        WTIMER0_ICR_R  = 0x00000001;                        /* clear timer0A timeout flag */
-        WTIMER0_IMR_R |= 0x00000001;                        /* arm timeout interrupt */
-        ROM_IntPrioritySet(INT_WTIMER0A, 32);
-        timer_irq_enable(dev);
-        timer_start(dev);
-        DEBUG("startTimeout Value=0x%lx\n", ROM_TimerValueGet(WTIMER0_BASE, TIMER_A));
-        return 1;
-    }
-    return -1;
+    if (dev >= TIMER_NUMOF){
+        return -1;
+    }
+
+    config[dev].cb = callback;                          /* User Function */
+    config[dev].divisor = us_per_tick * ROM_SysCtlClockGet()/1000000;
+
+    unsigned int sysctl_timer;
+    unsigned int timer_base;
+    unsigned int timer_side = TIMER_A;
+    unsigned int timer_cfg = TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PERIODIC_UP | TIMER_TAMR_TAMIE;
+    unsigned int timer_max_val;
+    unsigned int timer_intbit = TIMER_TIMA_TIMEOUT | TIMER_TIMA_MATCH;
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        sysctl_timer = SYSCTL_PERIPH_WTIMER0;
+        timer_base = WTIMER0_BASE;
+        timer_max_val = TIMER_0_MAX_VALUE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        sysctl_timer = SYSCTL_PERIPH_WTIMER1;
+        timer_base = WTIMER1_BASE;
+        timer_max_val = TIMER_1_MAX_VALUE;
+        break;
+#endif
+    default:
+        return -1; /* unreachable */
+    }
+
+
+    ROM_SysCtlPeripheralEnable(sysctl_timer);
+
+    ROM_TimerDisable(timer_base, timer_side);
+    ROM_TimerConfigure(timer_base, timer_cfg);
+
+    unsigned long long lltimer_val_max = _scaled_to_ll_value(timer_max_val, config[dev].divisor);
+
+    ROM_TimerPrescaleSet(timer_base, timer_side, lltimer_val_max >> 32);
+    ROM_TimerLoadSet(timer_base, timer_side, lltimer_val_max & 0xFFFFFFFF);
+    ROM_TimerIntClear(timer_base, timer_intbit);
+
+    ROM_TimerIntEnable(timer_base, timer_intbit);
+
+    timer_irq_enable(dev);
+    timer_start(dev);
+
+    return 0;
 }
 
 int timer_set(tim_t dev, int channel, unsigned int timeout)
 {
-    if (dev == TIMER_0) {
-        unsigned int now = timer_read(dev);
-        DEBUG("timer_set now=0x%x\n",now);
-        DEBUG("timer_set timeout=0x%x\n", timeout);
-        return timer_set_absolute(dev, channel, now+timeout);
+    unsigned int corrected_now;
+    int retval;
+
+    if (dev >= TIMER_NUMOF){
+        return -1;
     }
-    return -1;
+
+    corrected_now = timer_read(dev);
+    retval = timer_set_absolute(dev, channel, corrected_now+timeout);
+
+    return retval;
 }
 
 int timer_set_absolute(tim_t dev, int channel, unsigned int value)
 {
-    if (dev == TIMER_0) {
-        WTIMER0_TAILR_R = 0x00000000 | value;               /* period; Reload value */
-        DEBUG("Setting timer absolute value=0x%x\n", value);
-        return 1;
+    unsigned int timer_base;
+    unsigned int timer_side = TIMER_A;
+    unsigned long long scaledv;
+
+    if (dev >= TIMER_NUMOF){
+        return -1;
+    }
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        break;
+#endif
+    default:
+        return -1; /* unreachable */
+        break;
+    }
+    ROM_TimerDisable(timer_base, timer_side);
+
+    scaledv = _scaled_to_ll_value(value, config[dev].divisor);
+
+    if (scaledv>>32){
+        ROM_TimerPrescaleMatchSet(timer_base, timer_side, scaledv >> 32);
     }
-    return -1;
+    else {
+        ROM_TimerPrescaleMatchSet(timer_base, timer_side, 0);
+    }
+
+    ROM_TimerMatchSet(timer_base, timer_side, (unsigned long) (scaledv & 0xFFFFFFFF));
+    ROM_TimerEnable(timer_base, timer_side);
+
+    return 1;
 }
 
 int timer_clear(tim_t dev, int channel)
 {
-    if (dev == TIMER_0){
-        WTIMER0_ICR_R = TIMER_ICR_TATOCINT;
-        return 1;
+    unsigned int timer_intbit = TIMER_TIMA_TIMEOUT;
+    unsigned int timer_base;
+
+    if (dev >= TIMER_NUMOF){
+        return -1;
     }
-    return -1;
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        break;
+#endif
+    default:
+        return -1; /* unreachable */
+        break;
+    }
+
+    ROM_TimerIntClear(timer_base, timer_intbit);
+    return 1;
 }
 
 unsigned int timer_read(tim_t dev)
 {
-    if (dev == TIMER_0) {
-        unsigned int currTimer0Val=0;
-        unsigned int loadTimer0Val=0;
-        currTimer0Val = (unsigned int)ROM_TimerValueGet(WTIMER0_BASE, TIMER_A);
-        loadTimer0Val = (unsigned int)ROM_TimerLoadGet(WTIMER0_BASE, TIMER_A);
-        DEBUG("WTIMER0_TAILR_R=0x%lx\t currTimer0Val=0x%x\t loadTimer0Val=0x%x\n", WTIMER0_TAILR_R, currTimer0Val, loadTimer0Val);
-        return (loadTimer0Val - currTimer0Val);
+    unsigned int timer_base;
+    unsigned int timer_side = TIMER_A;
+    unsigned long long high_bits, high_bits_dup;
+    unsigned long long low_bits;
+    unsigned long long total;
+    unsigned int scaled_value;
+
+    if (dev >= TIMER_NUMOF){
+        return -1;
     }
-    return 0;
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        break;
+#endif
+    default:
+        return -1; /* unreachable */
+        break;
+    }
+
+    /* handle overflow happening between the 2 register reads */
+    do {
+      high_bits = ((unsigned long long)PRIV_TimerPrescaleSnapshotGet(timer_base, timer_side)) << 32;
+      low_bits = (unsigned long long)ROM_TimerValueGet(timer_base, timer_side);
+      high_bits_dup = ((unsigned long long)PRIV_TimerPrescaleSnapshotGet(timer_base, timer_side)) << 32;
+    } while (high_bits != high_bits_dup);
+
+    total = high_bits + low_bits;
+    DEBUG("Combined %lx:%lx\n", (unsigned long) (total>>32), (unsigned long) (total & 0xFFFFFFFF));
+
+    scaled_value = _llvalue_to_scaled_value(total, config[dev].divisor);
+
+    return scaled_value;
 }
 
 void timer_start(tim_t dev)
 {
-    if (dev == TIMER_0) {
-        ROM_TimerEnable(WTIMER0_BASE, TIMER_A);
+    unsigned int timer_base;
+    unsigned int timer_side = TIMER_A;
+
+    if (dev >= TIMER_NUMOF){
+        return ;
+    }
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        break;
+#endif
+    default:
+        return; /* unreachable */
     }
+
+    ROM_TimerEnable(timer_base, timer_side);
 }
 
 void timer_stop(tim_t dev)
 {
-    if (dev == TIMER_0) {
-        ROM_TimerDisable(WTIMER0_BASE, TIMER_A);
+    unsigned int timer_base;
+    unsigned int timer_side = TIMER_A;
+
+    if (dev >= TIMER_NUMOF){
+        return;
+    }
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        break;
+#endif
+    default:
+        return; /* unreachable */
     }
+
+    ROM_TimerDisable(timer_base, timer_side);
 }
 
 void timer_irq_enable(tim_t dev)
 {
-    if (dev == TIMER_0) {
-        ROM_IntEnable(INT_WTIMER0A);
-        ROM_TimerIntEnable(WTIMER0_BASE, TIMER_TIMA_TIMEOUT);
+    unsigned int timer_intbase;
+
+    if (dev >= TIMER_NUMOF){
+        return;
+    }
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_intbase = INT_WTIMER0A;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_intbase = INT_WTIMER1A;
+        break;
+#endif
+    default:
+        return; /* unreachable */
     }
+
+    ROM_IntPrioritySet(timer_intbase, 32);
+    ROM_IntEnable(timer_intbase);
 }
 
 void timer_irq_disable(tim_t dev)
 {
-    if (dev == TIMER_0) {
-        ROM_IntDisable(INT_WTIMER0A);
+    unsigned int timer_base;
+    unsigned int timer_intbit = TIMER_TIMA_TIMEOUT;
+    unsigned int timer_intbase;
+
+    if (dev >= TIMER_NUMOF){
+        return;
+    }
+
+    switch(dev){
+#if TIMER_0_EN
+    case TIMER_0:
+        timer_base = WTIMER0_BASE;
+        timer_intbase = INT_WTIMER0A;
+        break;
+#endif
+#if TIMER_1_EN
+    case TIMER_1:
+        timer_base = WTIMER1_BASE;
+        timer_intbase = INT_WTIMER1A;
+        break;
+#endif
+    default:
+        return; /* unreachable */
     }
+
+    ROM_IntEnable(timer_intbase);
+    ROM_TimerIntDisable(timer_base, timer_intbit);
 }
 
 #if TIMER_0_EN
-void isr_timer0a(void)
+void isr_wtimer0a(void)
 {
-    TIMER0_ICR_R = TIMER_ICR_TATOCINT;
+    /* Clears both IT */
+    ROM_TimerIntClear(WTIMER0_BASE, TIMER_TIMA_TIMEOUT | TIMER_TIMA_MATCH);
     config[TIMER_0].cb(0);
-
     if (sched_context_switch_request){
         thread_yield();
     }
 }
-void isr_wtimer0a(void)
+#endif /* TIMER_0_EN */
+
+#if TIMER_1_EN
+void isr_wtimer1a(void)
 {
-    WTIMER0_ICR_R = TIMER_ICR_TATOCINT;
+    ROM_TimerIntClear(WTIMER1_BASE, TIMER_TIMA_TIMEOUT | TIMER_TIMA_MATCH);
 
-    config[TIMER_0].cb(0);
+    config[TIMER_1].cb(0);
     if (sched_context_switch_request){
         thread_yield();
     }
 }
-#endif /* TIMER_0_EN */
+#endif /* TIMER_1_EN */
 
-#endif /* TIMER_0_EN */
+#endif /* TIMER_NUMOF */
 /** @} */