diff options
| author | Sean Cross <sean@xobs.io> | 2020-05-21 21:46:37 +0800 |
|---|---|---|
| committer | Sean Cross <sean@xobs.io> | 2020-05-21 21:46:37 +0800 |
| commit | fd4ef233c6d9b312c3582466c68390a16ddf15fa (patch) | |
| tree | 9155810b4e9e8bbaba2329f036f962efd8d0d91e | |
| parent | 77cf4dce8f1ae03edbe275cb82e250daeba8990f (diff) | |
nrf: port: add memory barrier before wfi
ARM recommends issuing a DSB instruction propr to issuing WFI, as it is
required on many parts suchas Cortex-M7. This is effectively a no-op on
the Cortex-M4 used in most NRF parts, however it ensures that we won't
be surprised when new parts come out.
See
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dai0321a/BIHICBGB.html
for more information.
Signed-off-by: Sean Cross <sean@xobs.io>
| -rw-r--r-- | ports/nrf/supervisor/port.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/ports/nrf/supervisor/port.c b/ports/nrf/supervisor/port.c index aa138e481..36725293c 100644 --- a/ports/nrf/supervisor/port.c +++ b/ports/nrf/supervisor/port.c @@ -273,8 +273,10 @@ void port_sleep_until_interrupt(void) { // available, even though the actual handler won't fire until // we re-enable interrupts. common_hal_mcu_disable_interrupts(); - if (!tud_task_event_ready()) + if (!tud_task_event_ready()) { + __DSB(); __WFI(); + } common_hal_mcu_enable_interrupts(); } } |