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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 9 | 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 | * Converted to use two 1K pages of STM32L1 Block Erasable Flash memory |
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| 6 | * instead of 4k of genuine word erasable NVRAM |
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| 7 | * on 1 Mar 2023 |
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| 8 | * Author: Mike |
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| 9 | */ |
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| 10 | |||
| 11 | /* Includes ------------------------------------------------------------------*/ |
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| 12 | #include "stm32f1xx_hal.h" |
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| 13 | |||
| 14 | #include "nvram.h" |
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| 15 | |||
| 16 | // erase page size on STM32F103 is 1kbytes |
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| 17 | #define NVRAM_PAGESIZE (1024 / sizeof(nvram_info_t)) |
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| 18 | |||
| 19 | // decided to allocate 2 pages of Flash as NVRAM |
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| 20 | #define NVRAM_WORDS (2 * NVRAM_PAGESIZE) |
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| 21 | |||
| 22 | // NVRAM hardware erases to all 0x |
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| 23 | nvram_info_t const HARDWARE_ERASED = {.u16 = 0UL}; |
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| 24 | // Marked as erased change to all 1 |
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| 25 | nvram_info_t const MARKED_ERASED = {.u16 = ~0UL}; |
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| 26 | |||
| 27 | // allocate the memory for storing the NVRAM data |
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| 28 | nvram_info_t NVRAM_Base[NVRAM_WORDS] __attribute__((section(".nvram"))); // set by linker |
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| 29 | |||
| 30 | static void |
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| 31 | WriteNVRAM(nvram_info_t *Address, nvram_info_t data) |
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| 32 | { |
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| 33 | HAL_FLASH_Unlock(); |
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| 34 | HAL_FLASH_Program(FLASH_TYPEPROGRAM_HALFWORD, (uint32_t)Address, data.u16); |
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| 35 | HAL_FLASH_Lock(); |
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| 36 | } |
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| 37 | |||
| 38 | static void |
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| 39 | EraseNVRAM(nvram_info_t *Address) |
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| 40 | { |
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| 41 | FLASH_EraseInitTypeDef erase = {.TypeErase = FLASH_TYPEERASE_PAGES, .PageAddress = Address, .NbPages = 1}; |
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| 42 | uint32_t err; |
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| 43 | HAL_FLASH_Unlock(); |
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| 44 | HAL_FLASHEx_Erase(&erase, &err); |
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| 45 | HAL_FLASH_Lock(); |
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| 46 | } |
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| 47 | |||
| 48 | // returns true if page crossed , used to trigger erasure of |
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| 49 | // the other page after copying out all data from other page to new page |
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| 50 | |||
| 51 | static uint8_t _write_nvram_data(nvram_info_t data, int *pIndex) |
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| 52 | { |
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| 53 | int base = *pIndex; |
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| 54 | uint8_t pageCrossed = 0; |
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| 55 | |||
| 56 | /* search blank */ |
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| 57 | for (int ptr = 0; ptr < NVRAM_WORDS; ptr++) |
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| 58 | { |
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| 59 | int index = (ptr + base) % NVRAM_WORDS; |
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| 60 | // erase the entry just found |
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| 61 | if (NVRAM_Base[index].data.tag == data.data.tag) |
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| 62 | { |
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| 63 | // erase previous data |
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| 64 | WriteNVRAM(&NVRAM_Base[index], MARKED_ERASED); |
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| 65 | base = ptr; |
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| 66 | break; |
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| 67 | } |
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| 68 | } |
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| 69 | // search forward for next erased or empty element, use it |
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| 70 | for (int offset = 1; offset < NVRAM_WORDS + 1; offset++) |
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| 71 | { |
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| 72 | int index = (base + offset) % NVRAM_WORDS; |
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| 73 | |||
| 74 | if (NVRAM_Base[index].u16 == HARDWARE_ERASED.u16) |
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| 75 | { |
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| 76 | // if we cross a page by incrementing into it need action |
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| 77 | if (index % NVRAM_PAGESIZE == 0) |
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| 78 | pageCrossed = 1; |
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| 79 | |||
| 80 | WriteNVRAM(&NVRAM_Base[index], data); |
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| 81 | // now check to see if it actually wrote correctly |
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| 82 | if (NVRAM_Base[index].u16 != data.u16) |
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| 83 | { |
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| 84 | WriteNVRAM(&NVRAM_Base[index], MARKED_ERASED); // Set to all 1 if the data did not write properly |
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| 85 | continue; |
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| 86 | } |
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| 87 | // record where the data was written |
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| 88 | *pIndex = index; |
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| 89 | return pageCrossed; |
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| 90 | } |
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| 91 | } |
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| 92 | // if it gets here, failure. |
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| 93 | return 0; |
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| 94 | } |
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| 95 | |||
| 96 | void write_nvram_data(nvram_info_t data) |
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| 97 | { |
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| 98 | int index = 0; |
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| 99 | // try the easy case - returns 0 , no further action |
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| 100 | if (!_write_nvram_data(data, &index)) |
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| 101 | return; |
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| 102 | // Returns 1, crossed page boundary with write of new data. |
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| 103 | // Now have the index pointing into the page where we need to copy the data to |
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| 104 | // for any data in the other page, copy it to the new page |
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| 105 | int oldPageBase = index >= NVRAM_PAGESIZE ? 0 : NVRAM_PAGESIZE; |
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| 106 | for (int i = oldPageBase; i < oldPageBase + NVRAM_WORDS; i++) |
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| 107 | { |
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| 108 | if (NVRAM_Base[i].u16 != HARDWARE_ERASED.u16 && NVRAM_Base[i].u16 != MARKED_ERASED.u16) |
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| 109 | { |
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| 110 | int base = i; |
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| 111 | // copy data forwards |
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| 112 | _write_nvram_data(NVRAM_Base[i], &base); |
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| 113 | } |
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| 114 | // erase the page we just copied out of |
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| 115 | EraseNVRAM(&NVRAM_Base[oldPageBase]); |
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| 116 | } |
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| 117 | } |
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| 118 | |||
| 119 | nvram_info_t *find_nvram_data(uint8_t searchTag) |
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| 120 | { |
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| 121 | for (int ptr = 0; ptr < NVRAM_WORDS; ptr++) |
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| 122 | { |
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| 123 | if (NVRAM_Base[ptr].data.tag == searchTag) |
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| 124 | return &NVRAM_Base[ptr]; |
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| 125 | } |
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| 126 | return NULL; |
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| 127 | } |