| Reinhard Meyer | c9c7606 | 2010-07-27 16:22:09 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 |
| 3 | * Reinhard Meyer, reinhard.meyer@emk-elektronik.de |
| 4 | * |
| 5 | * General Purpose Backup Registers |
| 6 | * Based on AT91SAM9XE datasheet |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; either version 2 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | */ |
| 13 | |
| 14 | #ifndef AT91_GPBR_H |
| 15 | #define AT91_GPBR_H |
| 16 | |
| 17 | /* |
| 18 | * The Atmel AT91SAM9 series has a small resource of 4 nonvolatile |
| 19 | * 32 Bit registers (buffered by the Vbu power). |
| 20 | * |
| 21 | * Please consider carefully before using this resource for tasks |
| 22 | * that do not really need nonvolatile registers. Maybe you can |
| 23 | * store information in EEPROM or FLASH instead. |
| 24 | * |
| 25 | * However, if you use a GPBR please document its use here and |
| 26 | * reference the define in your code! |
| 27 | * |
| 28 | * known typical uses of the GPBRs: |
| 29 | * GPBR[0]: offset for RTT timekeeping (u-boot, kernel) |
| 30 | * GPBR[1]: unused |
| 31 | * GPBR[2]: unused |
| 32 | * GPBR[3]: bootcount (u-boot) |
| 33 | */ |
| 34 | #define AT91_GPBR_INDEX_TIMEOFF 0 |
| 35 | #define AT91_GPBR_INDEX_BOOTCOUNT 3 |
| 36 | |
| 37 | #ifndef __ASSEMBLY__ |
| 38 | |
| 39 | typedef struct at91_gpbr { |
| 40 | u32 reg[4]; |
| 41 | } at91_gpbr_t; |
| 42 | |
| 43 | #endif /* __ASSEMBLY__ */ |
| 44 | |
| 45 | #endif |