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shared/runtime/softtimer: Generalise soft_timer to work without SysTick. 

If a port defines MICROPY_SOFT_TIMER_TICKS_MS then soft_timer assumes a
SysTick back end, and provides a soft_timer_next variable that sets when
the next call to soft_timer_handler() should occur.

Otherwise, a port should provide soft_timer_get_ms() and
soft_timer_schedule_at_ms() with appropriate semantics (see comments).

Existing users of soft_timer should continue to work as they did.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2023-11-14 13:19:31 +11:00
parent 9c7067d9ad
commit 516cc280e0
4 changed files with 63 additions and 38 deletions
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3
ports/renesas-ra/mphalport.h
View File

@ -29,6 +29,9 @@
#include "pin.h"
#include "py/ringbuf.h"
#define MICROPY_PY_PENDSV_ENTER uint32_t atomic_state = raise_irq_pri(IRQ_PRI_PENDSV)
#define MICROPY_PY_PENDSV_EXIT restore_irq_pri(atomic_state)
#define MICROPY_HW_USB_CDC_TX_TIMEOUT (500)
extern const unsigned char mp_hal_status_to_errno_table[4];

3
ports/samd/mphalport.h
View File

@ -35,6 +35,9 @@
#include "hpl_time_measure.h"
#include "sam.h"
#define MICROPY_PY_PENDSV_ENTER uint32_t atomic_state = raise_irq_pri(IRQ_PRI_PENDSV)
#define MICROPY_PY_PENDSV_EXIT restore_irq_pri(atomic_state)
#define MICROPY_HW_USB_CDC_TX_TIMEOUT (500)
extern int mp_interrupt_char;

75
shared/runtime/softtimer.c
View File

@ -30,42 +30,43 @@
#include "py/runtime.h"
#include "softtimer.h"
#ifdef MICROPY_SOFT_TIMER_TICKS_MS
extern __IO uint32_t MICROPY_SOFT_TIMER_TICKS_MS;
volatile uint32_t soft_timer_next;
static inline uint32_t soft_timer_get_ms(void) {
return MICROPY_SOFT_TIMER_TICKS_MS;
}
static void soft_timer_schedule_at_ms(uint32_t ticks_ms) {
uint32_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
uint32_t uw_tick = MICROPY_SOFT_TIMER_TICKS_MS;
if (soft_timer_ticks_diff(ticks_ms, uw_tick) <= 0) {
soft_timer_next = uw_tick + 1;
} else {
soft_timer_next = ticks_ms;
}
MICROPY_END_ATOMIC_SECTION(atomic_state);
}
#endif
// Pointer to the pairheap of soft timer objects.
// This may contain bss/data pointers as well as GC-heap pointers,
// and is explicitly GC traced by soft_timer_gc_mark_all().
STATIC soft_timer_entry_t *soft_timer_heap;
static inline int32_t ticks_diff(uint32_t t1, uint32_t t0) {
// t1 is after t0 (i.e. positive result) if there exists a uint32_t X <= INT_MAX
// such that t0 + X = t1. Otherwise t1 is interpreted to be earlier than
// t0 (negative result).
return t1 - t0;
}
STATIC int soft_timer_lt(mp_pairheap_t *n1, mp_pairheap_t *n2) {
soft_timer_entry_t *e1 = (soft_timer_entry_t *)n1;
soft_timer_entry_t *e2 = (soft_timer_entry_t *)n2;
return ticks_diff(e1->expiry_ms, e2->expiry_ms) < 0;
}
STATIC void soft_timer_schedule_systick(uint32_t ticks_ms) {
uint32_t irq_state = disable_irq();
uint32_t uw_tick = MICROPY_SOFT_TIMER_TICKS_MS;
if (ticks_diff(ticks_ms, uw_tick) <= 0) {
soft_timer_next = uw_tick + 1;
} else {
soft_timer_next = ticks_ms;
}
enable_irq(irq_state);
return soft_timer_ticks_diff(e1->expiry_ms, e2->expiry_ms) < 0;
}
void soft_timer_deinit(void) {
// Pop off all the nodes which are allocated on the GC-heap.
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
MICROPY_PY_PENDSV_ENTER;
soft_timer_entry_t *heap_from = soft_timer_heap;
soft_timer_entry_t *heap_to = (soft_timer_entry_t *)mp_pairheap_new(soft_timer_lt);
while (heap_from != NULL) {
@ -76,14 +77,14 @@ void soft_timer_deinit(void) {
}
}
soft_timer_heap = heap_to;
restore_irq_pri(irq_state);
MICROPY_PY_PENDSV_EXIT;
}
// Must be executed at IRQ_PRI_PENDSV
void soft_timer_handler(void) {
uint32_t ticks_ms = MICROPY_SOFT_TIMER_TICKS_MS;
uint32_t ticks_ms = soft_timer_get_ms();
soft_timer_entry_t *heap = soft_timer_heap;
while (heap != NULL && ticks_diff(heap->expiry_ms, ticks_ms) <= 0) {
while (heap != NULL && soft_timer_ticks_diff(heap->expiry_ms, ticks_ms) <= 0) {
soft_timer_entry_t *entry = heap;
heap = (soft_timer_entry_t *)mp_pairheap_pop(soft_timer_lt, &heap->pairheap);
if (entry->flags & SOFT_TIMER_FLAG_PY_CALLBACK) {
@ -97,19 +98,17 @@ void soft_timer_handler(void) {
}
}
soft_timer_heap = heap;
if (heap == NULL) {
// No more timers left, set largest delay possible
soft_timer_next = MICROPY_SOFT_TIMER_TICKS_MS;
} else {
// Set soft_timer_next so SysTick calls us back at the correct time
soft_timer_schedule_systick(heap->expiry_ms);
// Schedule the port's timer to call us back at the correct time.
if (heap != NULL) {
soft_timer_schedule_at_ms(heap->expiry_ms);
}
}
void soft_timer_gc_mark_all(void) {
// Mark all soft timer nodes that are allocated on the GC-heap.
// To avoid deep C recursion, pop and recreate the pairheap as nodes are marked.
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
MICROPY_PY_PENDSV_ENTER;
soft_timer_entry_t *heap_from = soft_timer_heap;
soft_timer_entry_t *heap_to = (soft_timer_entry_t *)mp_pairheap_new(soft_timer_lt);
while (heap_from != NULL) {
@ -121,7 +120,7 @@ void soft_timer_gc_mark_all(void) {
heap_to = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &heap_to->pairheap, &entry->pairheap);
}
soft_timer_heap = heap_to;
restore_irq_pri(irq_state);
MICROPY_PY_PENDSV_EXIT;
}
void soft_timer_static_init(soft_timer_entry_t *entry, uint16_t mode, uint32_t delta_ms, void (*cb)(soft_timer_entry_t *)) {
@ -134,18 +133,18 @@ void soft_timer_static_init(soft_timer_entry_t *entry, uint16_t mode, uint32_t d
void soft_timer_insert(soft_timer_entry_t *entry, uint32_t initial_delta_ms) {
mp_pairheap_init_node(soft_timer_lt, &entry->pairheap);
entry->expiry_ms = MICROPY_SOFT_TIMER_TICKS_MS + initial_delta_ms;
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
entry->expiry_ms = soft_timer_get_ms() + initial_delta_ms;
MICROPY_PY_PENDSV_ENTER;
soft_timer_heap = (soft_timer_entry_t *)mp_pairheap_push(soft_timer_lt, &soft_timer_heap->pairheap, &entry->pairheap);
if (entry == soft_timer_heap) {
// This new timer became the earliest one so set soft_timer_next
soft_timer_schedule_systick(entry->expiry_ms);
// This new timer became the earliest one so schedule a callback.
soft_timer_schedule_at_ms(entry->expiry_ms);
}
restore_irq_pri(irq_state);
MICROPY_PY_PENDSV_EXIT;
}
void soft_timer_remove(soft_timer_entry_t *entry) {
uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV);
MICROPY_PY_PENDSV_ENTER;
soft_timer_heap = (soft_timer_entry_t *)mp_pairheap_delete(soft_timer_lt, &soft_timer_heap->pairheap, &entry->pairheap);
restore_irq_pri(irq_state);
MICROPY_PY_PENDSV_EXIT;
}

20
shared/runtime/softtimer.h
View File

@ -48,6 +48,13 @@ typedef struct _soft_timer_entry_t {
extern volatile uint32_t soft_timer_next;
static inline int32_t soft_timer_ticks_diff(uint32_t t1, uint32_t t0) {
// t1 is after t0 (i.e. positive result) if there exists a uint32_t X <= INT_MAX
// such that t0 + X = t1. Otherwise t1 is interpreted to be earlier than
// t0 (negative result).
return t1 - t0;
}
void soft_timer_deinit(void);
void soft_timer_handler(void);
void soft_timer_gc_mark_all(void);
@ -63,4 +70,17 @@ static inline void soft_timer_reinsert(soft_timer_entry_t *entry, uint32_t initi
soft_timer_insert(entry, initial_delta_ms);
}
#if !defined(MICROPY_SOFT_TIMER_TICKS_MS)
// IF MICROPY_SOFT_TIMER_TICKS_MS is not defined then the port must provide the
// following timer functions:
// - soft_timer_get_ms() must return a 32-bit millisecond counter that wraps around.
// - soft_timer_schedule_at_ms(ticks_ms) must schedule a callback of soft_timer_handler()
// when the above millisecond counter reaches the given ticks_ms value. If ticks_ms
// is behind the current counter (using int32_t arithmetic) then the callback should
// be scheduled immediately. The callback of soft_timer_handler() should be made at
// pend-SV IRQ level, or equivalent.
uint32_t soft_timer_get_ms(void);
void soft_timer_schedule_at_ms(uint32_t ticks_ms);
#endif
#endif // MICROPY_INCLUDED_SHARED_RUNTIME_SOFTTIMER_H