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rp2/mpnetworkport: Fix lost CYW43 WiFi events when using both cores.

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There's a very odd but predictable sequence of events that breaks Wi-Fi
when using both cores:

1) CPU1 calls pendsv_suspend() - for example sleep() causes
   a softtimer node to be inserted, which calls pendsv_suspend().
2) CYW43 sends wakeup IRQ. CPU0 GPIO IRQ handler schedules PendSV
   and disables the GPIO IRQ on CPU0, to re-enable after
   cyw43_poll() runs and completes.
3) CPU0 PendSV_Handler runs, sees pendsv is suspended, exits.
4) CPU1 calls pendsv_resume() and pendsv_resume() sees PendSV
   is pending and triggers it on CPU1.
5) CPU1 runs PendSV_Handler, runs cyw43_poll(), and at the end
   it re-enables the IRQ *but now on CPU1*.

However CPU1 has GPIO IRQs disabled, so the CYW43 interrupt never runs
again...

The fix in this commit is to always enable/disable the interrupt on CPU0.
This isn't supported by the pico-sdk, but it is supported by the hardware.

Fixes issue #16779.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>
This commit is contained in:
Angus Gratton
2025-03-12 16:24:55 +11:00
committed by Damien George
parent dd7a950bbc
commit 6fa498cba1
1 changed files with 29 additions and 5 deletions
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34
ports/rp2/mpnetworkport.c
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@@ -59,13 +59,36 @@ static soft_timer_entry_t mp_network_soft_timer;
volatile int cyw43_has_pending = 0;
// The Pico SDK only lets us set GPIO wake on the current running CPU, but the
// hardware doesn't have this limit. We need to always enable/disable the pin
// interrupt on CPU0, regardless of which CPU runs PendSV and
// cyw43_post_poll_hook(). See feature request at https://github.com/raspberrypi/pico-sdk/issues/2354
static void gpio_set_cpu0_host_wake_irq_enabled(bool enable) {
// This is a re-implementation of gpio_set_irq_enabled() and _gpio_set_irq_enabled()
// from the pico-sdk, but with the core, gpio, and event type hardcoded to shrink
// code size.
io_bank0_irq_ctrl_hw_t *irq_ctrl_base = &io_bank0_hw->proc0_irq_ctrl;
uint32_t gpio = CYW43_PIN_WL_HOST_WAKE;
uint32_t events = CYW43_IRQ_LEVEL;
io_rw_32 *en_reg = &irq_ctrl_base->inte[gpio / 8];
events <<= 4 * (gpio % 8);
if (enable) {
hw_set_bits(en_reg, events);
} else {
hw_clear_bits(en_reg, events);
}
}
// GPIO IRQ always runs on CPU0
static void gpio_irq_handler(void) {
uint32_t events = gpio_get_irq_event_mask(CYW43_PIN_WL_HOST_WAKE);
if (events & CYW43_IRQ_LEVEL) {
// As we use a high level interrupt, it will go off forever until it's serviced.
// So disable the interrupt until this is done. It's re-enabled again by
// CYW43_POST_POLL_HOOK which is called at the end of cyw43_poll_func.
gpio_set_irq_enabled(CYW43_PIN_WL_HOST_WAKE, CYW43_IRQ_LEVEL, false);
// As we use a level interrupt (and can't use an edge interrupt
// as CYW43_PIN_WL_HOST_WAKE is also a SPI data pin), we need to disable
// the interrupt to stop it re-triggering until after PendSV run
// cyw43_poll(). It is re-enabled in cyw43_post_poll_hook(), implemented
// below.
gpio_set_cpu0_host_wake_irq_enabled(false);
cyw43_has_pending = 1;
__sev();
pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, cyw43_poll);
@@ -81,9 +104,10 @@ void cyw43_irq_init(void) {
#endif
}
// This hook will run on whichever CPU serviced the PendSV interrupt
void cyw43_post_poll_hook(void) {
cyw43_has_pending = 0;
gpio_set_irq_enabled(CYW43_PIN_WL_HOST_WAKE, CYW43_IRQ_LEVEL, true);
gpio_set_cpu0_host_wake_irq_enabled(true);
}
#endif