net: lib: nrf_cloud_fota_poll: Improvements and fixes

This patch includes several improvements and fixes to the
nRF Cloud CoAP FOTA polling library. The changes are as follows:

- Added a new API to apply the FOTA update after download, enabling
  asynchronous use and allowing the application to control when to shut
  down the modem pre applying a new modem image.
  This improves separation of concerns and modularity.
  For synchronous use, shutdown and FOTA application are handled
  internally by the library in the same function call.

- The library now polls every 10 percent for the status of the job
  to check if it has been canceled by the cloud during download.
  Previously, the library would simply download the firmware and
  apply it without verifying whether the job had been canceled
  by the cloud.

- Minor refactoring for improved readability and maintainability
  of the code.

For an example of using the asynchronous API, see:
https://github.com/nrfconnect/Asset-Tracker-Template

Signed-off-by: Simen S. Røstad <simen.rostad@nordicsemi.no>

Author: simensrostad

include/net/nrf_cloud.h

@@ -294,6 +294,12 @@ enum nrf_cloud_fota_status {
 	NRF_CLOUD_FOTA_CANCELED = 5,
 	NRF_CLOUD_FOTA_REJECTED = 6,
 	NRF_CLOUD_FOTA_DOWNLOADING = 7,
+
+	/* Validation for Full modem FOTA needed, disconnect from LTE network and call
+	 * nrf_cloud_fota_poll_update_apply(). This event is not reported to nRF Cloud and is only
+	 * used internally to signal the application to apply the full modem FOTA update.
+	 */
+	NRF_CLOUD_FOTA_FMFU_VALIDATION_NEEDED = 8,
 };
 
 /** @brief FOTA update type. */

include/net/nrf_cloud_fota_poll.h

@@ -51,6 +51,7 @@ struct nrf_cloud_fota_poll_ctx {
 	/* Internal variables */
 	struct nrf_cloud_rest_context *rest_ctx;
 	struct k_work_delayable timeout_work;
+	struct k_work_delayable cancel_work;
 	bool is_nonblocking;
 	bool full_modem_fota_supported;
 	const char *device_id;
@@ -136,6 +137,16 @@ int nrf_cloud_fota_poll_process_pending(struct nrf_cloud_fota_poll_ctx *ctx);
  */
 int nrf_cloud_fota_poll_process(struct nrf_cloud_fota_poll_ctx *ctx);
 
+/**
+ * @brief Apply downloaded image. For full modem FOTA this must be called after the network has
+ *	  been disconnected. Only applicable in non-blocking mode.
+ *
+ * @param[in] ctx Pointer to context used for FOTA polling operations.
+ *
+ * @return 0 on success, negative value on failure.
+ */
+int nrf_cloud_fota_poll_update_apply(struct nrf_cloud_fota_poll_ctx *ctx);
+
 /** @} */
 
 #ifdef __cplusplus

subsys/net/lib/nrf_cloud/Kconfig.nrf_cloud_fota

@@ -50,6 +50,7 @@ config NRF_CLOUD_FOTA_POLL
 	bool "FOTA job polling helpers (REST/CoAP)"
 	depends on !NRF_CLOUD_FOTA
 	depends on FOTA_DOWNLOAD
+	select FOTA_DOWNLOAD_PROGRESS_EVT
 	help
 	  When enabled, nRF Cloud FOTA job polling helpers will be built.  These
 	  functions make it easy to request, download, and handle modem, boot,