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- /*
- * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
- *
- * 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 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., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * You can also choose to distribute this program under the terms of
- * the Unmodified Binary Distribution Licence (as given in the file
- * COPYING.UBDL), provided that you have satisfied its requirements.
- */
-
- FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
- /** @file
- *
- * RTC-based time source
- *
- */
-
- #include <stdint.h>
- #include <time.h>
- #include <rtc.h>
- #include <ipxe/time.h>
-
- /**
- * Read RTC register
- *
- * @v address Register address
- * @ret data Data
- */
- static unsigned int rtc_readb ( int address ) {
- outb ( address, CMOS_ADDRESS );
- return inb ( CMOS_DATA );
- }
-
- /**
- * Check if RTC update is in progress
- *
- * @ret is_busy RTC update is in progress
- */
- static int rtc_is_busy ( void ) {
- return ( rtc_readb ( RTC_STATUS_A ) & RTC_STATUS_A_UPDATE_IN_PROGRESS );
- }
-
- /**
- * Read RTC BCD register
- *
- * @v address Register address
- * @ret value Value
- */
- static unsigned int rtc_readb_bcd ( int address ) {
- unsigned int bcd;
-
- bcd = rtc_readb ( address );
- return ( bcd - ( 6 * ( bcd >> 4 ) ) );
- }
-
- /**
- * Read RTC time
- *
- * @ret time Time, in seconds
- */
- static time_t rtc_read_time ( void ) {
- unsigned int status_b;
- int is_binary;
- int is_24hour;
- unsigned int ( * read_component ) ( int address );
- struct tm tm;
- int is_pm;
- unsigned int hour;
- time_t time;
-
- /* Wait for any in-progress update to complete */
- while ( rtc_is_busy() ) {}
-
- /* Determine RTC mode */
- status_b = rtc_readb ( RTC_STATUS_B );
- is_binary = ( status_b & RTC_STATUS_B_BINARY );
- is_24hour = ( status_b & RTC_STATUS_B_24_HOUR );
- read_component = ( is_binary ? rtc_readb : rtc_readb_bcd );
-
- /* Read time values */
- tm.tm_sec = read_component ( RTC_SEC );
- tm.tm_min = read_component ( RTC_MIN );
- hour = read_component ( RTC_HOUR );
- if ( ! is_24hour ) {
- is_pm = ( hour >= 80 );
- hour = ( ( ( ( hour & 0x7f ) % 80 ) % 12 ) +
- ( is_pm ? 12 : 0 ) );
- }
- tm.tm_hour = hour;
- tm.tm_mday = read_component ( RTC_MDAY );
- tm.tm_mon = ( read_component ( RTC_MON ) - 1 );
- tm.tm_year = ( read_component ( RTC_YEAR ) +
- 100 /* Assume we are in the 21st century, since
- * this code was written in 2012 */ );
-
- DBGC ( RTC_STATUS_A, "RTCTIME is %04d-%02d-%02d %02d:%02d:%02d "
- "(%s,%d-hour)\n", ( tm.tm_year + 1900 ), ( tm.tm_mon + 1 ),
- tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec,
- ( is_binary ? "binary" : "BCD" ), ( is_24hour ? 24 : 12 ) );
-
- /* Convert to seconds since the Epoch */
- time = mktime ( &tm );
-
- return time;
- }
-
- /**
- * Get current time in seconds
- *
- * @ret time Time, in seconds
- */
- static time_t rtc_now ( void ) {
- time_t time = 0;
- time_t last_time;
-
- /* Read time until we get two matching values in a row, in
- * case we end up reading a corrupted value in the middle of
- * an update.
- */
- do {
- last_time = time;
- time = rtc_read_time();
- } while ( time != last_time );
-
- return time;
- }
-
- PROVIDE_TIME ( rtc, time_now, rtc_now );
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