nrfConfigParamsPersistence.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2015 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #if defined(TARGET_NRF51822) || defined(TARGET_NRF52832) /* Persistent storage supported on nrf51 and nrf52 platforms */
00018 
00019 extern "C" {
00020     #include "fstorage.h"
00021 }
00022 
00023 #include "nrf_error.h"
00024 #include "../../EddystoneService.h"
00025 #include <cstddef>
00026 
00027 /**
00028  * Nordic specific structure used to store params persistently.
00029  * It extends EddystoneService::EddystoneParams_t with a persistence signature.
00030  */
00031 struct PersistentParams_t {
00032     EddystoneService::EddystoneParams_t params;
00033     uint32_t                         persistenceSignature; /* This isn't really a parameter, but having the expected
00034                                                             * magic value in this field indicates persistence. */
00035 
00036     static const uint32_t MAGIC = 0x1BEAC000;              /* Magic that identifies persistence */
00037 };
00038 
00039 /**
00040  * The following is a module-local variable to hold configuration parameters for
00041  * short periods during flash access. This is necessary because the fstorage
00042  * APIs don't copy in the memory provided as data source. The memory cannot be
00043  * freed or reused by the application until this flash access is complete. The
00044  * load and store operations in this module initialize persistentParams and then
00045  * pass it on to the 'fstorage' APIs.
00046  */
00047 static PersistentParams_t persistentParams;
00048 
00049 /**
00050  * Dummy callback handler needed by Nordic's fstorage module. This is called
00051  * after every flash access.
00052  */
00053 static void fs_evt_handler(fs_evt_t const * const evt, fs_ret_t result)
00054 {
00055     /* Supress compiler warnings */
00056     (void) evt;
00057     (void) result;
00058 }
00059 
00060 FS_REGISTER_CFG(fs_config_t fs_config) = {
00061     NULL,              // Begin pointer (set by fs_init)
00062     NULL,              // End pointer (set by fs_init)
00063     &fs_evt_handler,   // Function for event callbacks.
00064     1,                 // Number of physical flash pages required.
00065     0xFE               // Priority for flash usage.
00066 };
00067 
00068 
00069 void loadPersistentParams(void) {
00070     // copy from flash into persistent params struct
00071     memcpy(&persistentParams, fs_config.p_start_addr, sizeof(PersistentParams_t));
00072 }
00073 
00074 /* Platform-specific implementation for persistence on the nRF5x. Based on the
00075  * fstorage module provided by the Nordic SDK. */
00076 bool loadEddystoneServiceConfigParams(EddystoneService::EddystoneParams_t *paramsP)
00077 {
00078     static bool fstorageInited = false;
00079     if (!fstorageInited) {
00080         fs_init();
00081         fstorageInited = true;
00082     }
00083 
00084     loadPersistentParams();
00085 
00086     if ((persistentParams.persistenceSignature != PersistentParams_t::MAGIC)) {
00087         // On failure zero out and let the service reset to defaults
00088         memset(paramsP, 0, sizeof(EddystoneService::EddystoneParams_t));
00089         return false;
00090     }
00091 
00092     memcpy(paramsP, &persistentParams.params, sizeof(EddystoneService::EddystoneParams_t));
00093     return true;
00094 }
00095 
00096 /* Platform-specific implementation for persistence on the nRF5x. Based on the
00097  * fstorage module provided by the Nordic SDK. */
00098 void saveEddystoneServiceConfigParams(const EddystoneService::EddystoneParams_t *paramsP)
00099 {
00100     memcpy(&persistentParams.params, paramsP, sizeof(EddystoneService::EddystoneParams_t));
00101     if (persistentParams.persistenceSignature != PersistentParams_t::MAGIC) {
00102         persistentParams.persistenceSignature = PersistentParams_t::MAGIC;
00103     } else {
00104         fs_erase(&fs_config, fs_config.p_start_addr, sizeof(PersistentParams_t) / 4);
00105     }
00106 
00107     fs_store(&fs_config,
00108              fs_config.p_start_addr,
00109              reinterpret_cast<uint32_t *>(&persistentParams),
00110              sizeof(PersistentParams_t) / 4);
00111 }
00112 
00113 #endif /* #ifdef TARGET_NRF51822 */