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/irqchip/mips-gic.h>
28 #include <linux/timex.h>
29 #include <linux/mc146818rtc.h>
32 #include <asm/mipsregs.h>
33 #include <asm/mipsmtregs.h>
34 #include <asm/hardirq.h>
36 #include <asm/div64.h>
37 #include <asm/setup.h>
39 #include <asm/mc146818-time.h>
40 #include <asm/msc01_ic.h>
42 #include <asm/mips-boards/generic.h>
43 #include <asm/mips-boards/maltaint.h>
45 static int mips_cpu_timer_irq
;
46 static int mips_cpu_perf_irq
;
47 extern int cp0_perfcount_irq
;
49 static unsigned int gic_frequency
;
51 static void mips_timer_dispatch(void)
53 do_IRQ(mips_cpu_timer_irq
);
56 static void mips_perf_dispatch(void)
58 do_IRQ(mips_cpu_perf_irq
);
61 static unsigned int freqround(unsigned int freq
, unsigned int amount
)
64 freq
-= freq
% (amount
*2);
69 * Estimate CPU and GIC frequencies.
71 static void __init
estimate_frequencies(void)
74 unsigned int count
, start
;
75 cycle_t giccount
= 0, gicstart
= 0;
77 #if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
78 mips_hpt_frequency
= CONFIG_KVM_GUEST_TIMER_FREQ
* 1000000;
82 local_irq_save(flags
);
84 /* Start counter exactly on falling edge of update flag. */
85 while (CMOS_READ(RTC_REG_A
) & RTC_UIP
);
86 while (!(CMOS_READ(RTC_REG_A
) & RTC_UIP
));
88 /* Initialize counters. */
89 start
= read_c0_count();
92 gicstart
= gic_read_count();
95 /* Read counter exactly on falling edge of update flag. */
96 while (CMOS_READ(RTC_REG_A
) & RTC_UIP
);
97 while (!(CMOS_READ(RTC_REG_A
) & RTC_UIP
));
99 count
= read_c0_count();
101 giccount
= gic_read_count();
103 local_irq_restore(flags
);
106 mips_hpt_frequency
= count
;
109 giccount
-= gicstart
;
110 gic_frequency
= giccount
;
114 void read_persistent_clock(struct timespec
*ts
)
116 ts
->tv_sec
= mc146818_get_cmos_time();
120 int get_c0_fdc_int(void)
123 * Some cores claim the FDC is routable through the GIC, but it doesn't
124 * actually seem to be connected for those Malta bitstreams.
126 switch (current_cpu_type()) {
134 else if (gic_present
)
135 return gic_get_c0_fdc_int();
136 else if (cp0_fdc_irq
>= 0)
137 return MIPS_CPU_IRQ_BASE
+ cp0_fdc_irq
;
142 int get_c0_perfcount_int(void)
145 set_vi_handler(MSC01E_INT_PERFCTR
, mips_perf_dispatch
);
146 mips_cpu_perf_irq
= MSC01E_INT_BASE
+ MSC01E_INT_PERFCTR
;
147 } else if (gic_present
) {
148 mips_cpu_perf_irq
= gic_get_c0_perfcount_int();
149 } else if (cp0_perfcount_irq
>= 0) {
150 mips_cpu_perf_irq
= MIPS_CPU_IRQ_BASE
+ cp0_perfcount_irq
;
152 mips_cpu_perf_irq
= -1;
155 return mips_cpu_perf_irq
;
157 EXPORT_SYMBOL_GPL(get_c0_perfcount_int
);
159 unsigned int get_c0_compare_int(void)
162 set_vi_handler(MSC01E_INT_CPUCTR
, mips_timer_dispatch
);
163 mips_cpu_timer_irq
= MSC01E_INT_BASE
+ MSC01E_INT_CPUCTR
;
164 } else if (gic_present
) {
165 mips_cpu_timer_irq
= gic_get_c0_compare_int();
167 mips_cpu_timer_irq
= MIPS_CPU_IRQ_BASE
+ cp0_compare_irq
;
170 return mips_cpu_timer_irq
;
173 static void __init
init_rtc(void)
175 unsigned char freq
, ctrl
;
177 /* Set 32KHz time base if not already set */
178 freq
= CMOS_READ(RTC_FREQ_SELECT
);
179 if ((freq
& RTC_DIV_CTL
) != RTC_REF_CLCK_32KHZ
)
180 CMOS_WRITE(RTC_REF_CLCK_32KHZ
, RTC_FREQ_SELECT
);
182 /* Ensure SET bit is clear so RTC can run */
183 ctrl
= CMOS_READ(RTC_CONTROL
);
185 CMOS_WRITE(ctrl
& ~RTC_SET
, RTC_CONTROL
);
188 void __init
plat_time_init(void)
190 unsigned int prid
= read_c0_prid() & (PRID_COMP_MASK
| PRID_IMP_MASK
);
194 estimate_frequencies();
196 freq
= mips_hpt_frequency
;
197 if ((prid
!= (PRID_COMP_MIPS
| PRID_IMP_20KC
)) &&
198 (prid
!= (PRID_COMP_MIPS
| PRID_IMP_25KF
)))
200 freq
= freqround(freq
, 5000);
201 printk("CPU frequency %d.%02d MHz\n", freq
/1000000,
202 (freq
%1000000)*100/1000000);
204 mips_scroll_message();
207 /* Only Malta has a PIT. */
211 #ifdef CONFIG_MIPS_GIC
213 freq
= freqround(gic_frequency
, 5000);
214 printk("GIC frequency %d.%02d MHz\n", freq
/1000000,
215 (freq
%1000000)*100/1000000);
216 #ifdef CONFIG_CLKSRC_MIPS_GIC
217 gic_clocksource_init(gic_frequency
);