arch/mips/mti-malta/malta-time.c

   1 /*
   2  * Carsten Langgaard, carstenl@mips.com
   3  * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
   4  *
   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.
   8  *
   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
  12  *  for more details.
  13  *
  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.
  17  *
  18  * Setting up the clock on the MIPS boards.
  19  */
  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>
  30
  31 #include <asm/cpu.h>
  32 #include <asm/mipsregs.h>
  33 #include <asm/mipsmtregs.h>
  34 #include <asm/hardirq.h>
  35 #include <asm/irq.h>
  36 #include <asm/div64.h>
  37 #include <asm/setup.h>
  38 #include <asm/time.h>
  39 #include <asm/mc146818-time.h>
  40 #include <asm/msc01_ic.h>
  41
  42 #include <asm/mips-boards/generic.h>
  43 #include <asm/mips-boards/maltaint.h>
  44
  45 static int mips_cpu_timer_irq;
  46 static int mips_cpu_perf_irq;
  47 extern int cp0_perfcount_irq;
  48
  49 static unsigned int gic_frequency;
  50
  51 static void mips_timer_dispatch(void)
  52 {
  53         do_IRQ(mips_cpu_timer_irq);
  54 }
  55
  56 static void mips_perf_dispatch(void)
  57 {
  58         do_IRQ(mips_cpu_perf_irq);
  59 }
  60
  61 static unsigned int freqround(unsigned int freq, unsigned int amount)
  62 {
  63         freq += amount;
  64         freq -= freq % (amount*2);
  65         return freq;
  66 }
  67
  68 /*
  69  * Estimate CPU and GIC frequencies.
  70  */
  71 static void __init estimate_frequencies(void)
  72 {
  73         unsigned long flags;
  74         unsigned int count, start;
  75         cycle_t giccount = 0, gicstart = 0;
  76
  77 #if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
  78         mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
  79         return;
  80 #endif
  81
  82         local_irq_save(flags);
  83
  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));
  87
  88         /* Initialize counters. */
  89         start = read_c0_count();
  90         if (gic_present)
  91                 gicstart = gic_read_count();
  92
  93         /* Read counter exactly on falling edge of update flag. */
  94         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
  95         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
  96
  97         count = read_c0_count();
  98         if (gic_present)
  99                 giccount = gic_read_count();
 100
 101         local_irq_restore(flags);
 102
 103         count -= start;
 104         mips_hpt_frequency = count;
 105
 106         if (gic_present) {
 107                 giccount -= gicstart;
 108                 gic_frequency = giccount;
 109         }
 110 }
 111
 112 void read_persistent_clock(struct timespec *ts)
 113 {
 114         ts->tv_sec = mc146818_get_cmos_time();
 115         ts->tv_nsec = 0;
 116 }
 117
 118 int get_c0_perfcount_int(void)
 119 {
 120         if (cpu_has_veic) {
 121                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 122                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 123         } else if (gic_present) {
 124                 mips_cpu_perf_irq = gic_get_c0_perfcount_int();
 125         } else if (cp0_perfcount_irq >= 0) {
 126                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 127         } else {
 128                 mips_cpu_perf_irq = -1;
 129         }
 130
 131         return mips_cpu_perf_irq;
 132 }
 133
 134 unsigned int get_c0_compare_int(void)
 135 {
 136         if (cpu_has_veic) {
 137                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 138                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 139         } else if (gic_present) {
 140                 mips_cpu_timer_irq = gic_get_c0_compare_int();
 141         } else {
 142                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 143         }
 144
 145         return mips_cpu_timer_irq;
 146 }
 147
 148 static void __init init_rtc(void)
 149 {
 150         /* stop the clock whilst setting it up */
 151         CMOS_WRITE(RTC_SET | RTC_24H, RTC_CONTROL);
 152
 153         /* 32KHz time base */
 154         CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
 155
 156         /* start the clock */
 157         CMOS_WRITE(RTC_24H, RTC_CONTROL);
 158 }
 159
 160 void __init plat_time_init(void)
 161 {
 162         unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
 163         unsigned int freq;
 164
 165         init_rtc();
 166         estimate_frequencies();
 167
 168         freq = mips_hpt_frequency;
 169         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 170             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 171                 freq *= 2;
 172         freq = freqround(freq, 5000);
 173         printk("CPU frequency %d.%02d MHz\n", freq/1000000,
 174                (freq%1000000)*100/1000000);
 175
 176         mips_scroll_message();
 177
 178 #ifdef CONFIG_I8253
 179         /* Only Malta has a PIT. */
 180         setup_pit_timer();
 181 #endif
 182
 183 #ifdef CONFIG_MIPS_GIC
 184         if (gic_present) {
 185                 freq = freqround(gic_frequency, 5000);
 186                 printk("GIC frequency %d.%02d MHz\n", freq/1000000,
 187                        (freq%1000000)*100/1000000);
 188 #ifdef CONFIG_CLKSRC_MIPS_GIC
 189                 gic_clocksource_init(gic_frequency);
 190 #endif
 191         }
 192 #endif
 193 }