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rp2/rp2_pio: Make PIO IRQ handlers have lazy initialisation.

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This change has no impact on vanilla MicroPython builds, but is intended to
avoid RP2's PIO implementation from trampling PIO usage in USER_C_MODULES.

This is consistent with PIOs tracking of used state machines and managed
programs, and makes working with PIO in USER_C_MODULES much less of an
uphill battle.

Since PIO deinit runs before gc_sweep_all it's impossible to work around
this wrinkle otherwise.  A module finalizer does not get the opportunity to
put the PIOs back into a state which wont crash rp2_pio_deinit.

Changes are:
- init: Avoid exclusive handlers being added to all PIOs and add them only
  when needed.
- deinit: Only remove handlers we have set.
- rp2_pio_irq: Add the exlusive handler if needed.
- rp2_state_machine_irq: Add the exclusive handler if needed.

Signed-off-by: Phil Howard <phil@gadgetoid.com>
This commit is contained in:
Phil Howard 2024-07-08 15:34:18 +01:00 committed by Damien George
parent e7ff0b8a31
commit ad3552ae2c
1 changed files with 27 additions and 5 deletions
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32
ports/rp2/rp2_pio.c
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@ -104,6 +104,23 @@ static void pio1_irq0(void) {
pio_irq0(pio1);
}
// Returns the correct irq0 handler wrapper for a given pio
static inline irq_handler_t rp2_pio_get_irq_handler(PIO pio) {
return pio == pio0 ? pio0_irq0 : pio1_irq0;
}
// Add the irq0 handler if it's not added, and if no other handler is present
void rp2_pio_irq_set_exclusive_handler(PIO pio, uint irq) {
irq_handler_t current = irq_get_exclusive_handler(irq);
// If the IRQ is set and isn't our handler, or a shared handler is set, then raise an error
if ((current && current != rp2_pio_get_irq_handler(pio)) || irq_has_shared_handler(irq)) {
mp_raise_ValueError("irq claimed by external resource");
// If the IRQ is not set, add our handler
} else if (!current) {
irq_set_exclusive_handler(irq, rp2_pio_get_irq_handler(pio));
}
}
// Calls pio_add_program() and keeps track of used instruction memory.
static uint rp2_pio_add_managed_program(PIO pio, struct pio_program *pio_program) {
uint offset = pio_add_program(pio, pio_program);
@ -143,15 +160,18 @@ void rp2_pio_init(void) {
// Set up interrupts.
memset(MP_STATE_PORT(rp2_pio_irq_obj), 0, sizeof(MP_STATE_PORT(rp2_pio_irq_obj)));
memset(MP_STATE_PORT(rp2_state_machine_irq_obj), 0, sizeof(MP_STATE_PORT(rp2_state_machine_irq_obj)));
irq_set_exclusive_handler(PIO0_IRQ_0, pio0_irq0);
irq_set_exclusive_handler(PIO1_IRQ_0, pio1_irq0);
}
void rp2_pio_deinit(void) {
// Disable and clear interrupts.
irq_set_mask_enabled((1u << PIO0_IRQ_0) | (1u << PIO1_IRQ_0), false);
irq_remove_handler(PIO0_IRQ_0, pio0_irq0);
irq_remove_handler(PIO1_IRQ_0, pio1_irq0);
if (irq_get_exclusive_handler(PIO0_IRQ_0) == pio0_irq0) {
irq_set_enabled(PIO0_IRQ_0, false);
irq_remove_handler(PIO0_IRQ_0, pio0_irq0);
}
if (irq_get_exclusive_handler(PIO1_IRQ_0) == pio1_irq0) {
irq_set_enabled(PIO1_IRQ_0, false);
irq_remove_handler(PIO1_IRQ_0, pio1_irq0);
}
rp2_state_machine_reset_all();
@ -379,6 +399,7 @@ static mp_obj_t rp2_pio_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_t *k
// Enable IRQ if a handler is given.
if (args[ARG_handler].u_obj != mp_const_none) {
rp2_pio_irq_set_exclusive_handler(self->pio, self->irq);
self->pio->inte0 = irq->trigger;
irq_set_enabled(self->irq, true);
}
@ -872,6 +893,7 @@ static mp_obj_t rp2_state_machine_irq(size_t n_args, const mp_obj_t *pos_args, m
}
if (self->pio->inte0) {
rp2_pio_irq_set_exclusive_handler(self->pio, self->irq);
irq_set_enabled(self->irq, true);
}
}