diff options
| -rw-r--r-- | ports/rp2/main.c | 1 | ||||
| -rw-r--r-- | ports/rp2/pendsv.c | 32 | ||||
| -rw-r--r-- | ports/rp2/pendsv.h | 1 |
3 files changed, 27 insertions, 7 deletions
diff --git a/ports/rp2/main.c b/ports/rp2/main.c index 668017668..5fb47cc40 100644 --- a/ports/rp2/main.c +++ b/ports/rp2/main.c @@ -76,6 +76,7 @@ int main(int argc, char **argv) { // This is a tickless port, interrupts should always trigger SEV. SCB->SCR |= SCB_SCR_SEVONPEND_Msk; + pendsv_init(); soft_timer_init(); #if MICROPY_HW_ENABLE_UART_REPL diff --git a/ports/rp2/pendsv.c b/ports/rp2/pendsv.c index e4f662715..d24b4cb01 100644 --- a/ports/rp2/pendsv.c +++ b/ports/rp2/pendsv.c @@ -25,6 +25,7 @@ */ #include <assert.h> +#include "pico/mutex.h" #include "py/mpconfig.h" #include "pendsv.h" #include "RP2040.h" @@ -34,15 +35,21 @@ #endif static pendsv_dispatch_t pendsv_dispatch_table[PENDSV_DISPATCH_NUM_SLOTS]; -static int pendsv_lock; +static recursive_mutex_t pendsv_mutex; + +void pendsv_init(void) { + recursive_mutex_init(&pendsv_mutex); +} void pendsv_suspend(void) { - pendsv_lock++; + // Recursive Mutex here as either core may call pendsv_suspend() and expect + // both mutual exclusion (other core can't enter pendsv_suspend() at the + // same time), and that no PendSV handler will run. + recursive_mutex_enter_blocking(&pendsv_mutex); } void pendsv_resume(void) { - pendsv_lock--; - assert(pendsv_lock >= 0); + recursive_mutex_exit(&pendsv_mutex); // Run pendsv if needed. Find an entry with a dispatch and call pendsv dispatch // with it. If pendsv runs it will service all slots. int count = PENDSV_DISPATCH_NUM_SLOTS; @@ -55,9 +62,11 @@ void pendsv_resume(void) { } void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f) { - assert(pendsv_lock >= 0); pendsv_dispatch_table[slot] = f; - if (pendsv_lock == 0) { + if (pendsv_mutex.enter_count == 0) { + // There is a race here where other core calls pendsv_suspend() before + // ISR can execute, but dispatch will happen later when other core + // calls pendsv_resume(). SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; } else { #if MICROPY_PY_NETWORK_CYW43 @@ -68,7 +77,14 @@ void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f) { // PendSV interrupt handler to perform background processing. void PendSV_Handler(void) { - assert(pendsv_lock == 0); + + if (!recursive_mutex_try_enter(&pendsv_mutex, NULL)) { + // Failure here means core 1 holds pendsv_mutex. ISR will + // run again after core 1 calls pendsv_resume(). + return; + } + // Core 0 should not already have locked pendsv_mutex + assert(pensv_mutex.enter_count == 1); #if MICROPY_PY_NETWORK_CYW43 CYW43_STAT_INC(PENDSV_RUN_COUNT); @@ -81,4 +97,6 @@ void PendSV_Handler(void) { f(); } } + + recursive_mutex_exit(&pendsv_mutex); } diff --git a/ports/rp2/pendsv.h b/ports/rp2/pendsv.h index c9bdb2763..a5d944021 100644 --- a/ports/rp2/pendsv.h +++ b/ports/rp2/pendsv.h @@ -47,6 +47,7 @@ enum { typedef void (*pendsv_dispatch_t)(void); +void pendsv_init(void); void pendsv_suspend(void); void pendsv_resume(void); void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f); |