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authorWolfgang Denk <wd@denx.de>2010-09-08 00:42:00 +0200
committerWolfgang Denk <wd@denx.de>2010-09-08 00:42:00 +0200
commitcf64fda38e3d71e9077e11c673bd9be449c680da (patch)
treea847fb6cd48330482642ff92e34a7329b339acd2 /arch/arm/include/asm/arch-at91/at91_gpbr.h
parent09b4a9cf4003599f2cd609587dfa5f0b754640ed (diff)
parent5c3dab97c751e43103813472283305cbfe70d3f0 (diff)
Merge branch 'at91' of git://git.denx.de/u-boot-atmel
Diffstat (limited to 'arch/arm/include/asm/arch-at91/at91_gpbr.h')
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+/*
+ * Copyright (C) 2010
+ * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
+ *
+ * General Purpose Backup Registers
+ * Based on AT91SAM9XE datasheet
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef AT91_GPBR_H
+#define AT91_GPBR_H
+
+/*
+ * The Atmel AT91SAM9 series has a small resource of 4 nonvolatile
+ * 32 Bit registers (buffered by the Vbu power).
+ *
+ * Please consider carefully before using this resource for tasks
+ * that do not really need nonvolatile registers. Maybe you can
+ * store information in EEPROM or FLASH instead.
+ *
+ * However, if you use a GPBR please document its use here and
+ * reference the define in your code!
+ *
+ * known typical uses of the GPBRs:
+ * GPBR[0]: offset for RTT timekeeping (u-boot, kernel)
+ * GPBR[1]: unused
+ * GPBR[2]: unused
+ * GPBR[3]: bootcount (u-boot)
+ */
+#define AT91_GPBR_INDEX_TIMEOFF 0
+#define AT91_GPBR_INDEX_BOOTCOUNT 3
+
+#ifndef __ASSEMBLY__
+
+typedef struct at91_gpbr {
+ u32 reg[4];
+} at91_gpbr_t;
+
+#endif /* __ASSEMBLY__ */
+
+#endif