MicroBit as BLE gamepad
Fork of nRF51822 by
Diff: source/nRF5xGap.h
- Revision:
- 480:cf44bb89e3f1
- Parent:
- 479:f6e4a3f0a09a
- Child:
- 481:1762975cb3cb
diff -r f6e4a3f0a09a -r cf44bb89e3f1 source/nRF5xGap.h --- a/source/nRF5xGap.h Thu Nov 26 15:02:39 2015 +0000 +++ b/source/nRF5xGap.h Thu Nov 26 15:02:39 2015 +0000 @@ -113,84 +113,64 @@ #endif private: +#ifdef YOTTA_CFG_MBED_OS + /* + * In mbed OS, all user-facing BLE events (interrupts) are posted to the + * MINAR scheduler to be executed as callbacks in thread mode. MINAR guards + * its critical sections from interrupts by acquiring CriticalSectionLock, + * which results in a call to sd_nvic_critical_region_enter(). Thus, it is + * safe to invoke MINAR APIs from interrupt context as long as those + * interrupts are blocked by sd_nvic_critical_region_enter(). + * + * Radio notifications are a special case for the above. The Radio + * Notification IRQ is handled at a very high priority--higher than the + * level blocked by sd_nvic_critical_region_enter(). Thus Radio Notification + * events can preempt MINAR's critical sections. Using MINAR APIs (such as + * posting an event) directly in processRadioNotification() may result in a + * race condition ending in a hard-fault. + * + * The solution is to *not* call MINAR APIs directly from the Radio + * Notification handling; i.e. to do the bulk of RadioNotification + * processing at a reduced priority which respects MINAR's critical + * sections. Unfortunately, on a cortex-M0, there is no clean way to demote + * priority for the currently executing interrupt--we wouldn't want to + * demote the radio notification handling anyway because it is sensitive to + * timing, and the system expects to finish this handling very quickly. The + * workaround is to employ a Timeout to trigger + * postRadioNotificationCallback() after a very short delay (~0 us) and post + * the MINAR callback that context. + * + * !!!WARNING!!! Radio notifications are very time critical events. The + * current solution is expected to work under the assumption that + * postRadioNotificationCalback() will be executed BEFORE the next radio + * notification event is generated. + */ + bool radioNotificationCallbackParam; /* parameter to be passed into the Timeout-generated radio notification callback. */ Timeout radioNotificationTimeout; /* - * A helper function to post radio notification callbacks with low interrupt priority. + * A helper function to post radio notification callbacks through MINAR when using mbed OS. */ void postRadioNotificationCallback(void) { -#ifdef YOTTA_CFG_MBED_OS - /* - * In mbed OS, all user-facing BLE events (interrupts) are posted to the - * MINAR scheduler to be executed as callbacks in thread mode. MINAR guards - * its critical sections from interrupts by acquiring CriticalSectionLock, - * which results in a call to sd_nvic_critical_region_enter(). Thus, it is - * safe to invoke MINAR APIs from interrupt context as long as those - * interrupts are blocked by sd_nvic_critical_region_enter(). - * - * Radio notifications are a special case for the above. The Radio - * Notification IRQ is handled at a very high priority--higher than the - * level blocked by sd_nvic_critical_region_enter(). Thus Radio Notification - * events can preempt MINAR's critical sections. Using MINAR APIs (such as - * posting an event) directly in processRadioNotification() may result in a - * race condition ending in a hard-fault. - * - * The solution is to *not* call MINAR APIs directly from the Radio - * Notification handling; i.e. to do the bulk of RadioNotification - * processing at a reduced priority which respects MINAR's critical - * sections. Unfortunately, on a cortex-M0, there is no clean way to demote - * priority for the currently executing interrupt--we wouldn't want to - * demote the radio notification handling anyway because it is sensitive to - * timing, and the system expects to finish this handling very quickly. The - * workaround is to employ a Timeout to trigger - * postRadioNotificationCallback() after a very short delay (~0 us) and post - * the MINAR callback that context. - * - * !!!WARNING!!! Radio notifications are very time critical events. The - * current solution is expected to work under the assumption that - * postRadioNotificationCalback() will be executed BEFORE the next radio - * notification event is generated. - */ minar::Scheduler::postCallback( mbed::util::FunctionPointer1<void, bool>(&radioNotificationCallback, &FunctionPointerWithContext<bool>::call).bind(radioNotificationCallbackParam) ); -#else - /* - * In mbed classic, all user-facing BLE events execute callbacks in interrupt - * mode. Radio Notifications are a special case because its IRQ is handled at - * a very high priority. Thus Radio Notification events can preempt other - * operations that require interaction with the SoftDevice such as advertising - * payload updates and changing the Gap state. Therefore, executing a Radio - * Notification callback directly from processRadioNotification() may result - * in a race condition ending in a hard-fault. - * - * The solution is to *not* execute the Radio Notification callback directly - * from the Radio Notification handling; i.e. to do the bulk of the - * Radio Notification processing at a reduced priority. Unfortunately, on a - * cortex-M0, there is no clean way to demote priority for the currently - * executing interrupt--we wouldn't want to demote the radio notification - * handling anyway because it is sensitive to timing, and the system expects - * to finish this handling very quickly. The workaround is to employ a Timeout - * to trigger postRadioNotificationCallback() after a very short delay (~0 us) - * and execute the callback in that context. - * - * !!!WARNING!!! Radio notifications are very time critical events. The - * current solution is expected to work under the assumption that - * postRadioNotificationCalback() will be executed BEFORE the next radio - * notification event is generated. - */ - radioNotificationCallback.call(radioNotificationCallbackParam); + } #endif /* #ifdef YOTTA_CFG_MBED_OS */ - } /** * A helper function to process radio-notification events; to be called internally. * @param param [description] */ void processRadioNotificationEvent(bool param) { +#ifdef YOTTA_CFG_MBED_OS + /* When using mbed OS the callback to the user-defined function will be posted through minar */ radioNotificationCallbackParam = param; radioNotificationTimeout.attach_us(this, &nRF5xGap::postRadioNotificationCallback, 0); +#else + radioNotificationCallback.call(param); +#endif } friend void radioNotificationStaticCallback(bool param); /* allow invocations of processRadioNotificationEvent() */