1 /* SPDX-License-Identifier: GPL-2.0+ */
4 * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
6 * General Purpose Backup Registers
7 * Based on AT91SAM9XE datasheet
14 * The Atmel AT91SAM9 series has a small resource of 4 nonvolatile
15 * 32 Bit registers (buffered by the Vbu power).
17 * Please consider carefully before using this resource for tasks
18 * that do not really need nonvolatile registers. Maybe you can
19 * store information in EEPROM or FLASH instead.
21 * However, if you use a GPBR please document its use here and
22 * reference the define in your code!
24 * known typical uses of the GPBRs:
25 * GPBR[0]: offset for RTT timekeeping (u-boot, kernel)
28 * GPBR[3]: bootcount (u-boot)
30 #define AT91_GPBR_INDEX_TIMEOFF 0
31 #define AT91_GPBR_INDEX_BOOTCOUNT 3
35 typedef struct at91_gpbr {
39 #endif /* __ASSEMBLY__ */