2 * Carsten Langgaard, carstenl@mips.com
3 * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved.
5 * This program is free software; you can distribute it and/or modify it
6 * under the terms of the GNU General Public License (Version 2) as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
18 * Setting up the clock on the MIPS boards.
20 #include <linux/types.h>
21 #include <linux/i8253.h>
22 #include <linux/init.h>
23 #include <linux/kernel_stat.h>
24 #include <linux/sched.h>
25 #include <linux/spinlock.h>
26 #include <linux/interrupt.h>
27 #include <linux/timex.h>
28 #include <linux/mc146818rtc.h>
30 #include <asm/mipsregs.h>
31 #include <asm/mipsmtregs.h>
32 #include <asm/hardirq.h>
34 #include <asm/div64.h>
35 #include <asm/setup.h>
37 #include <asm/mc146818-time.h>
38 #include <asm/msc01_ic.h>
41 #include <asm/mips-boards/generic.h>
42 #include <asm/mips-boards/prom.h>
44 #include <asm/mips-boards/maltaint.h>
46 unsigned long cpu_khz;
49 static int mips_cpu_timer_irq;
50 static int mips_cpu_perf_irq;
51 extern int cp0_perfcount_irq;
53 static void mips_timer_dispatch(void)
55 do_IRQ(mips_cpu_timer_irq);
58 static void mips_perf_dispatch(void)
60 do_IRQ(mips_cpu_perf_irq);
63 static unsigned int freqround(unsigned int freq, unsigned int amount)
66 freq -= freq % (amount*2);
71 * Estimate CPU and GIC frequencies.
73 static void __init estimate_frequencies(void)
76 unsigned int count, start;
77 unsigned int giccount = 0, gicstart = 0;
79 local_irq_save(flags);
81 /* Start counter exactly on falling edge of update flag. */
82 while (CMOS_READ(RTC_REG_A) & RTC_UIP);
83 while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
85 /* Initialize counters. */
86 start = read_c0_count();
88 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), gicstart);
90 /* Read counter exactly on falling edge of update flag. */
91 while (CMOS_READ(RTC_REG_A) & RTC_UIP);
92 while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
94 count = read_c0_count();
96 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), giccount);
98 local_irq_restore(flags);
102 giccount -= gicstart;
104 mips_hpt_frequency = count;
106 gic_frequency = giccount;
109 void read_persistent_clock(struct timespec *ts)
111 ts->tv_sec = mc146818_get_cmos_time();
115 static void __init plat_perf_setup(void)
117 #ifdef MSC01E_INT_BASE
119 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
120 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
123 if (cp0_perfcount_irq >= 0) {
125 set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
126 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
128 irq_set_handler(mips_cpu_perf_irq, handle_percpu_irq);
133 unsigned int __cpuinit get_c0_compare_int(void)
135 #ifdef MSC01E_INT_BASE
137 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
138 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
143 set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
144 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
147 return mips_cpu_timer_irq;
150 void __init plat_time_init(void)
152 unsigned int prid = read_c0_prid() & 0xffff00;
155 estimate_frequencies();
157 freq = mips_hpt_frequency;
158 if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
159 (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
161 freq = freqround(freq, 5000);
162 pr_debug("CPU frequency %d.%02d MHz\n", freq/1000000,
163 (freq%1000000)*100/1000000);
164 cpu_khz = freq / 1000;
167 freq = freqround(gic_frequency, 5000);
168 pr_debug("GIC frequency %d.%02d MHz\n", freq/1000000,
169 (freq%1000000)*100/1000000);
170 gic_clocksource_init(gic_frequency);
172 init_r4k_clocksource();
175 /* Only Malta has a PIT. */
179 mips_scroll_message();