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/timex.h>
  28 #include <linux/mc146818rtc.h>
  29
  30 #include <asm/mipsregs.h>
  31 #include <asm/mipsmtregs.h>
  32 #include <asm/hardirq.h>
  33 #include <asm/irq.h>
  34 #include <asm/div64.h>
  35 #include <asm/setup.h>
  36 #include <asm/time.h>
  37 #include <asm/mc146818-time.h>
  38 #include <asm/msc01_ic.h>
  39 #include <asm/gic.h>
  40
  41 #include <asm/mips-boards/generic.h>
  42 #include <asm/mips-boards/prom.h>
  43
  44 #include <asm/mips-boards/maltaint.h>
  45
  46 unsigned long cpu_khz;
  47 int gic_frequency;
  48
  49 static int mips_cpu_timer_irq;
  50 static int mips_cpu_perf_irq;
  51 extern int cp0_perfcount_irq;
  52
  53 static void mips_timer_dispatch(void)
  54 {
  55         do_IRQ(mips_cpu_timer_irq);
  56 }
  57
  58 static void mips_perf_dispatch(void)
  59 {
  60         do_IRQ(mips_cpu_perf_irq);
  61 }
  62
  63 static unsigned int freqround(unsigned int freq, unsigned int amount)
  64 {
  65         freq += amount;
  66         freq -= freq % (amount*2);
  67         return freq;
  68 }
  69
  70 /*
  71  * Estimate CPU and GIC frequencies.
  72  */
  73 static void __init estimate_frequencies(void)
  74 {
  75         unsigned long flags;
  76         unsigned int count, start;
  77         unsigned int giccount = 0, gicstart = 0;
  78
  79 #if defined (CONFIG_KVM_GUEST) && defined (CONFIG_KVM_HOST_FREQ)
  80         unsigned int prid = read_c0_prid() & 0xffff00;
  81
  82         /*
  83          * XXXKYMA: hardwire the CPU frequency to Host Freq/4
  84          */
  85         count = (CONFIG_KVM_HOST_FREQ * 1000000) >> 3;
  86         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
  87             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
  88                 count *= 2;
  89
  90         mips_hpt_frequency = count;
  91         return;
  92 #endif
  93
  94         local_irq_save(flags);
  95
  96         /* Start counter exactly on falling edge of update flag. */
  97         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
  98         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
  99
 100         /* Initialize counters. */
 101         start = read_c0_count();
 102         if (gic_present)
 103                 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), gicstart);
 104
 105         /* Read counter exactly on falling edge of update flag. */
 106         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 107         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
 108
 109         count = read_c0_count();
 110         if (gic_present)
 111                 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), giccount);
 112
 113         local_irq_restore(flags);
 114
 115         count -= start;
 116         if (gic_present)
 117                 giccount -= gicstart;
 118
 119         mips_hpt_frequency = count;
 120         if (gic_present)
 121                 gic_frequency = giccount;
 122 }
 123
 124 void read_persistent_clock(struct timespec *ts)
 125 {
 126         ts->tv_sec = mc146818_get_cmos_time();
 127         ts->tv_nsec = 0;
 128 }
 129
 130 static void __init plat_perf_setup(void)
 131 {
 132 #ifdef MSC01E_INT_BASE
 133         if (cpu_has_veic) {
 134                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 135                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 136         } else
 137 #endif
 138         if (cp0_perfcount_irq >= 0) {
 139                 if (cpu_has_vint)
 140                         set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
 141                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 142 #ifdef CONFIG_SMP
 143                 irq_set_handler(mips_cpu_perf_irq, handle_percpu_irq);
 144 #endif
 145         }
 146 }
 147
 148 unsigned int __cpuinit get_c0_compare_int(void)
 149 {
 150 #ifdef MSC01E_INT_BASE
 151         if (cpu_has_veic) {
 152                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 153                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 154         } else
 155 #endif
 156         {
 157                 if (cpu_has_vint)
 158                         set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
 159                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 160         }
 161
 162         return mips_cpu_timer_irq;
 163 }
 164
 165 void __init plat_time_init(void)
 166 {
 167         unsigned int prid = read_c0_prid() & 0xffff00;
 168         unsigned int freq;
 169
 170         estimate_frequencies();
 171
 172         freq = mips_hpt_frequency;
 173         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 174             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 175                 freq *= 2;
 176         freq = freqround(freq, 5000);
 177         pr_debug("CPU frequency %d.%02d MHz\n", freq/1000000,
 178                (freq%1000000)*100/1000000);
 179         cpu_khz = freq / 1000;
 180
 181         if (gic_present) {
 182                 freq = freqround(gic_frequency, 5000);
 183                 pr_debug("GIC frequency %d.%02d MHz\n", freq/1000000,
 184                        (freq%1000000)*100/1000000);
 185                 gic_clocksource_init(gic_frequency);
 186         } else
 187                 init_r4k_clocksource();
 188
 189 #ifdef CONFIG_I8253
 190         /* Only Malta has a PIT. */
 191         setup_pit_timer();
 192 #endif
 193
 194         mips_scroll_message();
 195
 196         plat_perf_setup();
 197 }