1 /* 2 * (C) Copyright 2010 3 * Reinhard Meyer, reinhard.meyer@emk-elektronik.de 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24 /* 25 * Date & Time support for the internal Real-time Timer 26 * of AT91SAM9260 and compatibles. 27 * Compatible with the LinuX rtc driver workaround: 28 * The RTT cannot be written to, but only reset. 29 * The actual time is the sum of RTT and one of 30 * the four GPBR registers. 31 * 32 * The at91sam9260 has 4 GPBR (0-3). 33 * For their typical use see at91_gpbr.h ! 34 * 35 * make sure u-boot and kernel use the same GPBR ! 36 */ 37 38 #include <common.h> 39 #include <command.h> 40 #include <rtc.h> 41 #include <asm/errno.h> 42 #include <asm/arch/hardware.h> 43 #include <asm/arch/io.h> 44 #include <asm/arch/at91_rtt.h> 45 #include <asm/arch/at91_gpbr.h> 46 47 #if defined(CONFIG_CMD_DATE) 48 49 int rtc_get (struct rtc_time *tmp) 50 { 51 at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; 52 at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; 53 ulong tim; 54 ulong tim2; 55 ulong off; 56 57 do { 58 tim = readl(&rtt->vr); 59 tim2 = readl(&rtt->vr); 60 } while (tim!=tim2); 61 off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); 62 /* off==0 means time is invalid, but we ignore that */ 63 to_tm (tim+off, tmp); 64 return 0; 65 } 66 67 int rtc_set (struct rtc_time *tmp) 68 { 69 at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; 70 at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; 71 ulong tim; 72 73 tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday, 74 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 75 76 /* clear alarm, set prescaler to 32768, clear counter */ 77 writel(32768+AT91_RTT_RTTRST, &rtt->mr); 78 writel(~0, &rtt->ar); 79 writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); 80 /* wait for counter clear to happen, takes less than a 1/32768th second */ 81 while (readl(&rtt->vr) != 0) 82 ; 83 return 0; 84 } 85 86 void rtc_reset (void) 87 { 88 at91_rtt_t *rtt = (at91_rtt_t *) AT91_RTT_BASE; 89 at91_gpbr_t *gpbr = (at91_gpbr_t *) AT91_GPR_BASE; 90 91 /* clear alarm, set prescaler to 32768, clear counter */ 92 writel(32768+AT91_RTT_RTTRST, &rtt->mr); 93 writel(~0, &rtt->ar); 94 writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]); 95 /* wait for counter clear to happen, takes less than a 1/32768th second */ 96 while (readl(&rtt->vr) != 0) 97 ; 98 } 99 100 #endif 101