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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 66 | mjames | 1 | /* |
| 2 | * nvram.c |
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| 3 | * |
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| 4 | * Created on: 4 Jun 2017 |
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| 5 | * Author: Mike |
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| 6 | */ |
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| 7 | |||
| 8 | /* Includes ------------------------------------------------------------------*/ |
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| 9 | #include "stm32l1xx_hal.h" |
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| 10 | |||
| 11 | #include "nvram.h" |
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| 12 | |||
| 13 | // NVRAM hardware erases to all 0x |
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| 14 | nvram_info_t const HARDWARE_ERASED = {.u32 = 0UL}; |
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| 15 | // Marked as erased change to all 1 |
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| 16 | nvram_info_t const MARKED_ERASED = {.u32 = ~0UL}; |
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| 17 | // marked as unusable change pattern to something in between |
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| 18 | nvram_info_t const MARKED_UNUSABLE = {.u32 = 0x55555555UL}; |
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| 19 | |||
| 20 | nvram_info_t NVRAM_Base[NVRAM_WORDS] __attribute__((section(".NVRAM_Data"))); // set by linker |
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| 21 | |||
| 22 | static void |
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| 23 | WriteNVRAM(nvram_info_t *Address, nvram_info_t data) |
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| 24 | { |
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| 25 | HAL_FLASHEx_DATAEEPROM_Unlock(); |
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| 26 | HAL_FLASHEx_DATAEEPROM_Program(FLASH_TYPEPROGRAMDATA_WORD, (uint32_t)Address, data.u32); |
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| 27 | HAL_FLASHEx_DATAEEPROM_Lock(); |
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| 28 | } |
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| 29 | |||
| 30 | static void |
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| 31 | EraseNVRAM(nvram_info_t *Address) |
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| 32 | { |
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| 33 | HAL_FLASHEx_DATAEEPROM_Unlock(); |
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| 34 | HAL_FLASHEx_DATAEEPROM_Erase(FLASH_TYPEERASEDATA_WORD, (uint32_t)Address); |
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| 35 | HAL_FLASHEx_DATAEEPROM_Lock(); |
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| 36 | } |
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| 37 | |||
| 38 | void write_nvram_data(nvram_info_t data) |
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| 39 | { |
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| 40 | int base = 0; |
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| 41 | |||
| 42 | /* search blank */ |
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| 43 | for (int ptr = 0; ptr < NVRAM_WORDS; ptr++) |
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| 44 | { |
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| 45 | // erase the entry just found |
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| 46 | if (NVRAM_Base[ptr].data.tag == data.data.tag) |
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| 47 | { |
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| 79 | mjames | 48 | // erase previous data, delete any entries that have a matching tag |
| 66 | mjames | 49 | WriteNVRAM(&NVRAM_Base[ptr], MARKED_ERASED); |
| 79 | mjames | 50 | // record the next location to the marked erased location |
| 51 | // so that future writes occur further along in the Flash |
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| 52 | if (base == 0) |
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| 53 | base = ptr; |
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| 66 | mjames | 54 | } |
| 55 | } |
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| 79 | mjames | 56 | |
| 66 | mjames | 57 | // search forward for next erased or empty element, use it |
| 58 | for (int offset = 1; offset < NVRAM_WORDS + 1; offset++) |
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| 59 | { |
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| 60 | int index = (base + offset) % NVRAM_WORDS; |
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| 61 | if (NVRAM_Base[index].u32 == MARKED_ERASED.u32 || NVRAM_Base[index].u32 == HARDWARE_ERASED.u32) |
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| 62 | { |
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| 63 | if (NVRAM_Base[index].u32 != HARDWARE_ERASED.u32) |
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| 64 | EraseNVRAM(&NVRAM_Base[index]); |
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| 65 | WriteNVRAM(&NVRAM_Base[index], data); |
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| 66 | // now check to see if it actually went |
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| 67 | if (NVRAM_Base[index].u32 != data.u32) |
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| 68 | { |
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| 69 | WriteNVRAM(&NVRAM_Base[index], MARKED_UNUSABLE); // mark as neither unused or used |
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| 70 | continue; |
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| 71 | } |
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| 72 | return; |
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| 73 | } |
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| 74 | } |
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| 75 | } |
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| 76 | |||
| 77 | nvram_info_t *find_nvram_data(uint8_t searchTag) |
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| 78 | { |
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| 79 | for (int ptr = 0; ptr < NVRAM_WORDS; ptr++) |
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| 80 | { |
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| 81 | if (NVRAM_Base[ptr].data.tag == searchTag) |
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| 82 | return &NVRAM_Base[ptr]; |
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| 83 | } |
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| 84 | return NULL; |
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| 85 | } |
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| 70 | mjames | 86 | |
| 87 | void erase_nvram() |
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| 88 | { |
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| 89 | /* search blank */ |
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| 90 | for (int ptr = 0; ptr < NVRAM_WORDS; ptr++) |
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| 91 | { |
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| 92 | EraseNVRAM(&NVRAM_Base[ptr]); |
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| 93 | } |
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| 94 | } |