Microvisor Polite Deployment

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#define SYS_NT_BUFFER_SIZE_R 8 // Value in # of records, not bytes
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/*
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* Set up the system notification system -- typically in main()
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*/
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// Store the notification center handle
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MvNotificationHandle sys_notification_center_handle;
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MvSystemEventHandle  sys_event_handle;
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volatile uint32_t    current_notification_index = 0;
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volatile bool        update_pending = false;
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// Central store for system notifications
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volatile struct MvNotification sys_notification_center[SYS_NT_BUFFER_SIZE_R] __attribute__((aligned(8)));
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// Clear the notification store
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memset((void *)sys_notification_center, 0xFF, sizeof(sys_notification_center));
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// Configure a notification center for system-centric notifications
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static struct MvNotificationSetup sys_notification_config = {
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    .irq = TIM1_BRK_IRQn,
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    .buffer = (struct MvNotification *)sys_notification_center,
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    .buffer_size = sizeof(sys_notification_center)
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};
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// Ask Microvisor to establish the notification center
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// and confirm that it has accepted the request
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enum MvStatus status = mvSetupNotifications(&sys_notification_config, &sys_notification_center_handle);
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assert(status == MV_STATUS_OKAY);
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assert(sys_notification_center_handle != 0);
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// Tell Microvisor to use the new notification center for system notifications
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const struct MvOpenSystemNotificationParams sys_notification_params = {
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    .notification_handle = sys_notification_center_handle,
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    .notification_tag = 0,
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    .notification_source = MV_SYSTEMNOTIFICATIONSOURCE_UPDATE
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};
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status = mvOpenSystemNotification(&sys_notification_params, &sys_event_handle);
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assert(status == MV_STATUS_OKAY);
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assert(sys_event_handle != 0);
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// Start the notification IRQ
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NVIC_ClearPendingIRQ(TIM1_BRK_IRQn);
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NVIC_EnableIRQ(TIM1_BRK_IRQn);
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...
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while(1) {
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    if (update_pending) {
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        // Update pending -- can we go ahead?
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        // NOTE `critical_task_running()` is a dummy function not provided here
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        if (!critical_task_running()) {
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            enum MvStatus status = mvRestart(MV_RESTART_AUTOAPPLYUPDATE);
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            // If the above call succeeds, the app with restart.
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            // If not, report the failure code
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            char err_msg_buffer[40] = {0};
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            sprintf(buffer, "Application restart failed (code %lu)", status);
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            mvServerLog((const uint8_t*)buffer, (uint16_t)strlen(buffer));
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        }
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    }
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}
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...
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/*
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* Set up the notification ISR
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*/
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void TIM1_BRK_IRQHandler(void) {
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    // Check for a suitable event
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    bool got_notification = false;
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    volatile struct MvNotification notification = sys_notification_center[current_notification_index];
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    if (notification.event_type == MV_EVENTTYPE_UPDATEDOWNLOADED) {
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        // Flag there is an update pending
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        update_pending = true;
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        got_notification = true;
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    }
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    if (got_notification) {
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        // Point to the next record to be written
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        current_notification_index = (current_notification_index + 1) % SYS_NT_BUFFER_SIZE_R;
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        // Clear the current notifications event
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        // See https://www.twilio.com/docs/iot/microvisor/microvisor-notifications#buffer-overruns
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        notification.event_type = 0;
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    }
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}