alif/system_tick: Integrate soft timer.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

ports/alif/main.c

@@ -33,6 +33,7 @@
 #include "shared/readline/readline.h"
 #include "shared/runtime/gchelper.h"
 #include "shared/runtime/pyexec.h"
+#include "shared/runtime/softtimer.h"
 #include "shared/tinyusb/mp_usbd.h"
 #include "tusb.h"
 #include "mpuart.h"
@@ -119,6 +120,7 @@ void _start(void) {
 
     soft_reset_exit:
         mp_printf(MP_PYTHON_PRINTER, "MPY: soft reboot\n");
+        soft_timer_deinit();
         gc_sweep_all();
         mp_deinit();
     }

ports/alif/mphalport.c

@@ -31,11 +31,13 @@
 #include "py/stream.h"
 #include "extmod/misc.h"
 #include "shared/runtime/interrupt_char.h"
+#include "shared/runtime/softtimer.h"
 #include "shared/timeutils/timeutils.h"
 #include "shared/tinyusb/mp_usbd.h"
 #include "shared/tinyusb/mp_usbd_cdc.h"
 #include "tusb.h"
 #include "mpuart.h"
+#include "pendsv.h"
 #include "system_tick.h"
 
 #ifndef MICROPY_HW_STDIN_BUFFER_LEN
@@ -146,3 +148,18 @@ void mp_hal_delay_ms(mp_uint_t ms) {
 uint64_t mp_hal_time_ns(void) {
     return 0;
 }
+
+void system_tick_schedule_callback(void) {
+    pendsv_schedule_dispatch(PENDSV_DISPATCH_SOFT_TIMER, soft_timer_handler);
+}
+
+uint32_t soft_timer_get_ms(void) {
+    return mp_hal_ticks_ms();
+}
+
+void soft_timer_schedule_at_ms(uint32_t ticks_ms) {
+    int32_t ms = soft_timer_ticks_diff(ticks_ms, mp_hal_ticks_ms());
+    ms = MAX(0, ms);
+    ms = MIN(ms, 4000000); // ensure ms * 1000 doesn't overflow
+    system_tick_schedule_after_us(ms * 1000);
+}

ports/alif/system_tick.c

@@ -59,9 +59,13 @@ void system_tick_init(void) {
     utimer_control_enable(UTIMER, UTIMER_CHANNEL);
     utimer_counter_start(UTIMER, UTIMER_CHANNEL);
 
-    // Set up the UTIMER compare interrupt, to be used later.
+    // Set up the UTIMER compare A interrupt, to be used by system_tick_wfe_with_timeout_us.
     system_tick_nvic_config(2);
     UTIMER->UTIMER_CHANNEL_CFG[UTIMER_CHANNEL].UTIMER_COMPARE_CTRL_A |= COMPARE_CTRL_DRV_COMPARE_EN;
+
+    // Set up the UTIMER compare B interrupt, to be used by soft-timer.
+    system_tick_nvic_config(4);
+    UTIMER->UTIMER_CHANNEL_CFG[UTIMER_CHANNEL].UTIMER_COMPARE_CTRL_B |= COMPARE_CTRL_DRV_COMPARE_EN;
 }
 
 // COMPARE_A_BUF1
@@ -73,6 +77,17 @@ void UTIMER_IRQ90Handler(void) {
     }
 }
 
+// COMPARE_B_BUF1
+void UTIMER_IRQ92Handler(void) {
+    uint32_t chan_interrupt = UTIMER->UTIMER_CHANNEL_CFG[UTIMER_CHANNEL].UTIMER_CHAN_INTERRUPT;
+    if (chan_interrupt & CHAN_INTERRUPT_COMPARE_B_BUF1_MASK) {
+        utimer_clear_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+        utimer_mask_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+        system_tick_schedule_callback();
+        __SEV();
+    }
+}
+
 // OVER_FLOW
 void UTIMER_IRQ95Handler(void) {
     uint32_t chan_interrupt = UTIMER->UTIMER_CHANNEL_CFG[UTIMER_CHANNEL].UTIMER_CHAN_INTERRUPT;
@@ -106,7 +121,7 @@ uint64_t system_tick_get_u64(void) {
 }
 
 void system_tick_wfe_with_timeout_us(uint32_t timeout_us) {
-    // Maximum 10 second timeout, to not overflow signed 32-bit ticks when
+    // Maximum 10 second timeout, to not overflow 32-bit ticks when
     // system_core_clock_mhz==400.
     uint32_t timeout_ticks = MIN(timeout_us, 10000000) * system_core_clock_mhz;
 
@@ -126,3 +141,28 @@ void system_tick_wfe_with_timeout_us(uint32_t timeout_us) {
     // Disable the UTIMER compare interrupt.
     utimer_mask_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_A_BUF1_MASK);
 }
+
+void system_tick_schedule_after_us(uint32_t ticks_us) {
+    // Disable the interrupt in case it's still active.
+    utimer_mask_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+
+    // Maximum 10 second timeout, to not overflow 32-bit ticks when
+    // system_core_clock_mhz==400.
+    uint32_t timeout_ticks = MIN(ticks_us, 10000000) * system_core_clock_mhz;
+
+    // Set up the UTIMER compare interrupt to fire after the given timeout.
+    uint32_t cntr = utimer_get_count(UTIMER, UTIMER_CHANNEL, UTIMER_CNTR);
+    utimer_set_count(UTIMER, UTIMER_CHANNEL, UTIMER_COMPARE_B_BUF1, cntr + timeout_ticks);
+    utimer_clear_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+    utimer_unmask_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+
+    // Handle the case of short timeouts.
+    uint32_t cntr2 = utimer_get_count(UTIMER, UTIMER_CHANNEL, UTIMER_CNTR);
+    if ((uint32_t)(cntr2 - cntr) >= timeout_ticks) {
+        if (!(UTIMER->UTIMER_CHANNEL_CFG[UTIMER_CHANNEL].UTIMER_CHAN_INTERRUPT_MASK & CHAN_INTERRUPT_COMPARE_B_BUF1_MASK)) {
+            // Interrupt is still enabled, so disable it and manually call the callback.
+            utimer_mask_interrupt(UTIMER, UTIMER_CHANNEL, CHAN_INTERRUPT_COMPARE_B_BUF1_MASK);
+            system_tick_schedule_callback();
+        }
+    }
+}

ports/alif/system_tick.h

@@ -34,5 +34,7 @@ void system_tick_init(void);
 uint32_t system_tick_get_u32(void);
 uint64_t system_tick_get_u64(void);
 void system_tick_wfe_with_timeout_us(uint32_t timeout_us);
+void system_tick_schedule_after_us(uint32_t ticks_us);
+void system_tick_schedule_callback(void);
 
 #endif // MICROPY_INCLUDED_ALIF_SYSTEM_TICK_H