From: Reinhard Meyer info@emk-elektronik.de
--- arch/arm/include/asm/arch-at91/at91_gpbr.h | 45 +++++++++++++ arch/arm/include/asm/arch-at91/at91_rtt.h | 36 ++++++++++ drivers/rtc/Makefile | 1 + drivers/rtc/at91sam9_rtt.c | 100 ++++++++++++++++++++++++++++ 4 files changed, 182 insertions(+), 0 deletions(-) create mode 100644 arch/arm/include/asm/arch-at91/at91_gpbr.h create mode 100644 arch/arm/include/asm/arch-at91/at91_rtt.h create mode 100644 drivers/rtc/at91sam9_rtt.c
diff --git a/arch/arm/include/asm/arch-at91/at91_gpbr.h b/arch/arm/include/asm/arch-at91/at91_gpbr.h new file mode 100644 index 0000000..cf1d790 --- /dev/null +++ b/arch/arm/include/asm/arch-at91/at91_gpbr.h @@ -0,0 +1,45 @@ +/* + * 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 diff --git a/arch/arm/include/asm/arch-at91/at91_rtt.h b/arch/arm/include/asm/arch-at91/at91_rtt.h new file mode 100644 index 0000000..e0253ef --- /dev/null +++ b/arch/arm/include/asm/arch-at91/at91_rtt.h @@ -0,0 +1,36 @@ +/* + * Copyright (C) 2010 + * Reinhard Meyer, reinhard.meyer@emk-elektronik.de + * + * Real-time Timer + * 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_RTT_H +#define AT91_RTT_H + +#ifndef __ASSEMBLY__ + +typedef struct at91_rtt { + u32 mr; /* Mode Register RW 0x00008000 */ + u32 ar; /* Alarm Register RW 0xFFFFFFFF */ + u32 vr; /* Value Register RO 0x00000000 */ + u32 sr; /* Status Register RO 0x00000000 */ +} at91_rtt_t; + +#endif /* __ASSEMBLY__ */ + +#define AT91_RTT_MR_RTPRES 0x0000ffff +#define AT91_RTT_MR_ALMIEN 0x00010000 +#define AT91_RTT_RTTINCIEN 0x00020000 +#define AT91_RTT_RTTRST 0x00040000 + +#define AT91_RTT_SR_ALMS 0x00000001 +#define AT91_RTT_SR_RTTINC 0x00000002 + +#endif diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 772a49a..98734db 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -27,6 +27,7 @@ include $(TOPDIR)/config.mk
LIB = $(obj)librtc.a
+COBJS-$(CONFIG_RTC_AT91SAM9_RTT) += at91sam9_rtt.o COBJS-$(CONFIG_RTC_BFIN) += bfin_rtc.o COBJS-y += date.o COBJS-$(CONFIG_RTC_DS12887) += ds12887.o diff --git a/drivers/rtc/at91sam9_rtt.c b/drivers/rtc/at91sam9_rtt.c new file mode 100644 index 0000000..de8e30d --- /dev/null +++ b/drivers/rtc/at91sam9_rtt.c @@ -0,0 +1,100 @@ +/* + * (C) Copyright 2010 + * Reinhard Meyer, reinhard.meyer@emk-elektronik.de + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/* + * Date & Time support for the internal Real-time Timer + * of AT91SAM9260 and compatibles. + * Compatible with the LinuX rtc driver workaround: + * The RTT cannot be written to, but only reset. + * The actual time is the sum of RTT and one of + * the four GPBR registers. + * + * The at91sam9260 has 4 GPBR (0-3). + * For their typical use see at91_gpbr.h ! + * + * make sure u-boot and kernel use the same GPBR ! + */ + +#include <common.h> +#include <command.h> +#include <rtc.h> +#include <asm/errno.h> +#include <asm/arch/hardware.h> +#include <asm/arch/io.h> +#include <asm/arch/at91_rtt.h> +#include <asm/arch/at91_gpbr.h> + +#if defined(CONFIG_CMD_DATE) + +int rtc_get (struct rtc_time *tmp) +{ + at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; + at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; + ulong tim; + ulong tim2; + ulong off; + + do { + tim = readl(&rtt->vr); + tim2 = readl(&rtt->vr); + } while (tim!=tim2); + off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); + /* off==0 means time is invalid, but we ignore that */ + to_tm (tim+off, tmp); + return 0; +} + +int rtc_set (struct rtc_time *tmp) +{ + at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; + at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; + ulong tim; + + tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); + + /* clear alarm, set prescaler to 32768, clear counter */ + writel(32768+AT91_RTT_RTTRST, &rtt->mr); + writel(~0, &rtt->ar); + writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); + /* wait for counter clear to happen, takes less than a 1/32768th second */ + while (readl(&rtt->vr) != 0) + ; + return 0; +} + +void rtc_reset (void) +{ + at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; + at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; + + /* clear alarm, set prescaler to 32768, clear counter */ + writel(32768+AT91_RTT_RTTRST, &rtt->mr); + writel(~0, &rtt->ar); + writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); + /* wait for counter clear to happen, takes less than a 1/32768th second */ + while (readl(&rtt->vr) != 0) + ; +} + +#endif