1/* 2 * DEC I/O ASIC's counter clocksource 3 * 4 * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20#include <linux/clocksource.h> 21#include <linux/init.h> 22 23#include <asm/ds1287.h> 24#include <asm/time.h> 25#include <asm/dec/ioasic.h> 26#include <asm/dec/ioasic_addrs.h> 27 28static cycle_t dec_ioasic_hpt_read(struct clocksource *cs) 29{ 30 return ioasic_read(IO_REG_FCTR); 31} 32 33static struct clocksource clocksource_dec = { 34 .name = "dec-ioasic", 35 .read = dec_ioasic_hpt_read, 36 .mask = CLOCKSOURCE_MASK(32), 37 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 38}; 39 40void __init dec_ioasic_clocksource_init(void) 41{ 42 unsigned int freq; 43 u32 start, end; 44 int i = HZ / 10; 45 46 47 while (!ds1287_timer_state()) 48 ; 49 50 start = dec_ioasic_hpt_read(&clocksource_dec); 51 52 while (i--) 53 while (!ds1287_timer_state()) 54 ; 55 56 end = dec_ioasic_hpt_read(&clocksource_dec); 57 58 freq = (end - start) * 10; 59 printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); 60 61 clocksource_dec.rating = 200 + freq / 10000000; 62 clocksource_set_clock(&clocksource_dec, freq); 63 64 clocksource_register(&clocksource_dec); 65} 66