eeprom_transient.c (1931B)
1 /* Copyright 2019 Nick Brassel (tzarc) 2 * 3 * This program is free software: you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License as published by 5 * the Free Software Foundation, either version 2 of the License, or 6 * (at your option) any later version. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17 #include <stdint.h> 18 #include <string.h> 19 20 #include "eeprom_driver.h" 21 #include "eeprom_transient.h" 22 23 __attribute__((aligned(4))) static uint8_t transientBuffer[TRANSIENT_EEPROM_SIZE] = {0}; 24 25 size_t clamp_length(intptr_t offset, size_t len) { 26 if (offset + len > TRANSIENT_EEPROM_SIZE) { 27 len = TRANSIENT_EEPROM_SIZE - offset; 28 } 29 30 return len; 31 } 32 33 void eeprom_driver_init(void) {} 34 35 void eeprom_driver_format(bool erase) { 36 /* The transient eeprom driver doesn't necessarily need to be formatted before use, and it always starts up filled with zeros, due to placement in the .bss section */ 37 if (erase) { 38 eeprom_driver_erase(); 39 } 40 } 41 42 void eeprom_driver_erase(void) { 43 memset(transientBuffer, 0x00, TRANSIENT_EEPROM_SIZE); 44 } 45 46 void eeprom_read_block(void *buf, const void *addr, size_t len) { 47 intptr_t offset = (intptr_t)addr; 48 memset(buf, 0x00, len); 49 len = clamp_length(offset, len); 50 if (len > 0) { 51 memcpy(buf, &transientBuffer[offset], len); 52 } 53 } 54 55 void eeprom_write_block(const void *buf, void *addr, size_t len) { 56 intptr_t offset = (intptr_t)addr; 57 len = clamp_length(offset, len); 58 if (len > 0) { 59 memcpy(&transientBuffer[offset], buf, len); 60 } 61 }