dc74ae83da
The motivation for doing this is so that we can allow common_hal_mcu_disable_interrupts in IRQ context, something that works on other ports, but not on nRF with SD enabled. This is because when SD is enabled, calling sd_softdevice_is_enabled in the context of an interrupt with priority 2 or 3 causes a HardFault. We have chosen to give the USB interrupt priority 2 on nRF, the highest priority that is compatible with SD. Since at least SoftDevice s130 v2.0.1, sd_nvic_critical_region_enter/exit have been implemented as inline functions and are safe to call even if softdevice is not enabled. Reference kindly provided by danh: https://devzone.nordicsemi.com/f/nordic-q-a/29553/sd_nvic_critical_region_enter-exit-missing-in-s130-v2 Switching to these as the default/only way to enable/disable interrupts simplifies things, and fixes several problems and potential problems: * Interrupts at priority 2 or 3 could not call common_hal_mcu_disable_interrupts because the call to sd_softdevice_is_enabled would HardFault * Hypothetically, the state of sd_softdevice_is_enabled could change from the disable to the enable call, meaning the calls would not match (__disable_irq() could be balanced with sd_nvic_critical_region_exit). This also fixes a problem I believe would exist if disable() were called twice when SD is enabled. There is a single "is_nested_critical_region" flag, and the second call would set it to 1. Both of the enable() calls that followed would call critical_region_exit(1), and interrupts would not properly be reenabled. In the new version of the code, we use our own nesting_count value to track the intended state, so now nested disable()s only call critical_region_enter() once, only updating is_nested_critical_region once; and only the second enable() call will call critical_region_exit, with the right value of i_n_c_r. Finally, in port_sleep_until_interrupt, if !sd_enabled, we really do need to __disable_irq, rather than using the common_hal_mcu routines; the reason why is documented in a comment. |
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| .. | ||
| _bleio | ||
| analogio | ||
| audiobusio | ||
| audiopwmio | ||
| board | ||
| busio | ||
| digitalio | ||
| displayio | ||
| microcontroller | ||
| neopixel_write | ||
| nvm | ||
| os | ||
| pulseio | ||
| rgbmatrix | ||
| rotaryio | ||
| rtc | ||
| supervisor | ||
| watchdog | ||