1 /* 2 * PowerNV Real Time Clock. 3 * 4 * Copyright 2011 IBM Corp. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 13 #include <linux/kernel.h> 14 #include <linux/time.h> 15 #include <linux/bcd.h> 16 #include <linux/rtc.h> 17 #include <linux/delay.h> 18 #include <linux/platform_device.h> 19 #include <linux/of_platform.h> 20 21 #include <asm/opal.h> 22 #include <asm/firmware.h> 23 #include <asm/machdep.h> 24 25 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm) 26 { 27 tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) + 28 bcd2bin((y_m_d >> 16) & 0xff)) - 1900; 29 tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1; 30 tm->tm_mday = bcd2bin(y_m_d & 0xff); 31 tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff); 32 tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff); 33 tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff); 34 tm->tm_wday = -1; 35 } 36 37 time64_t __init opal_get_boot_time(void) 38 { 39 struct rtc_time tm; 40 u32 y_m_d; 41 u64 h_m_s_ms; 42 __be32 __y_m_d; 43 __be64 __h_m_s_ms; 44 long rc = OPAL_BUSY; 45 46 if (!opal_check_token(OPAL_RTC_READ)) 47 return 0; 48 49 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { 50 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms); 51 if (rc == OPAL_BUSY_EVENT) { 52 mdelay(OPAL_BUSY_DELAY_MS); 53 opal_poll_events(NULL); 54 } else if (rc == OPAL_BUSY) { 55 mdelay(OPAL_BUSY_DELAY_MS); 56 } 57 } 58 if (rc != OPAL_SUCCESS) 59 return 0; 60 61 y_m_d = be32_to_cpu(__y_m_d); 62 h_m_s_ms = be64_to_cpu(__h_m_s_ms); 63 opal_to_tm(y_m_d, h_m_s_ms, &tm); 64 return rtc_tm_to_time64(&tm); 65 } 66 67 static __init int opal_time_init(void) 68 { 69 struct platform_device *pdev; 70 struct device_node *rtc; 71 72 rtc = of_find_node_by_path("/ibm,opal/rtc"); 73 if (rtc) { 74 pdev = of_platform_device_create(rtc, "opal-rtc", NULL); 75 of_node_put(rtc); 76 } else { 77 if (opal_check_token(OPAL_RTC_READ) || 78 opal_check_token(OPAL_READ_TPO)) 79 pdev = platform_device_register_simple("opal-rtc", -1, 80 NULL, 0); 81 else 82 return -ENODEV; 83 } 84 85 return PTR_ERR_OR_ZERO(pdev); 86 } 87 machine_subsys_initcall(powernv, opal_time_init); 88