arch/mips/mips-boards/generic/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
  21 #include <linux/types.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/time.h>
  28 #include <linux/timex.h>
  29 #include <linux/mc146818rtc.h>
  30
  31 #include <asm/mipsregs.h>
  32 #include <asm/mipsmtregs.h>
  33 #include <asm/hardirq.h>
  34 #include <asm/i8253.h>
  35 #include <asm/irq.h>
  36 #include <asm/div64.h>
  37 #include <asm/cpu.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/prom.h>
  44
  45 #ifdef CONFIG_MIPS_ATLAS
  46 #include <asm/mips-boards/atlasint.h>
  47 #endif
  48 #ifdef CONFIG_MIPS_MALTA
  49 #include <asm/mips-boards/maltaint.h>
  50 #endif
  51 #ifdef CONFIG_MIPS_SEAD
  52 #include <asm/mips-boards/seadint.h>
  53 #endif
  54
  55 unsigned long cpu_khz;
  56
  57 static int mips_cpu_timer_irq;
  58 extern int cp0_perfcount_irq;
  59
  60 static void mips_timer_dispatch(void)
  61 {
  62         do_IRQ(mips_cpu_timer_irq);
  63 }
  64
  65 static void mips_perf_dispatch(void)
  66 {
  67         do_IRQ(cp0_perfcount_irq);
  68 }
  69
  70 /*
  71  * Estimate CPU frequency.  Sets mips_hpt_frequency as a side-effect
  72  */
  73 static unsigned int __init estimate_cpu_frequency(void)
  74 {
  75         unsigned int prid = read_c0_prid() & 0xffff00;
  76         unsigned int count;
  77
  78 #if defined(CONFIG_MIPS_SEAD) || defined(CONFIG_MIPS_SIM)
  79         /*
  80          * The SEAD board doesn't have a real time clock, so we can't
  81          * really calculate the timer frequency
  82          * For now we hardwire the SEAD board frequency to 12MHz.
  83          */
  84
  85         if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
  86             (prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
  87                 count = 12000000;
  88         else
  89                 count = 6000000;
  90 #endif
  91 #if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA)
  92         unsigned long flags;
  93         unsigned int start;
  94
  95         local_irq_save(flags);
  96
  97         /* Start counter exactly on falling edge of update flag */
  98         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
  99         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
 100
 101         /* Start r4k counter. */
 102         start = read_c0_count();
 103
 104         /* Read counter exactly on falling edge of update flag */
 105         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 106         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
 107
 108         count = read_c0_count() - start;
 109
 110         /* restore interrupts */
 111         local_irq_restore(flags);
 112 #endif
 113
 114         mips_hpt_frequency = count;
 115         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 116             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 117                 count *= 2;
 118
 119         count += 5000;    /* round */
 120         count -= count%10000;
 121
 122         return count;
 123 }
 124
 125 unsigned long read_persistent_clock(void)
 126 {
 127         return mc146818_get_cmos_time();
 128 }
 129
 130 void __init plat_perf_setup(void)
 131 {
 132         cp0_perfcount_irq = -1;
 133
 134 #ifdef MSC01E_INT_BASE
 135         if (cpu_has_veic) {
 136                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 137                 cp0_perfcount_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 138         } else
 139 #endif
 140         if (cp0_perfcount_irq >= 0) {
 141                 if (cpu_has_vint)
 142                         set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
 143 #ifdef CONFIG_SMP
 144                 set_irq_handler(cp0_perfcount_irq, handle_percpu_irq);
 145 #endif
 146         }
 147 }
 148
 149 unsigned int __cpuinit get_c0_compare_int(void)
 150 {
 151 #ifdef MSC01E_INT_BASE
 152         if (cpu_has_veic) {
 153                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 154                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 155         } else
 156 #endif
 157         {
 158                 if (cpu_has_vint)
 159                         set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
 160                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 161         }
 162
 163         return mips_cpu_timer_irq;
 164 }
 165
 166 void __init plat_time_init(void)
 167 {
 168         unsigned int est_freq;
 169
 170         /* Set Data mode - binary. */
 171         CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
 172
 173         est_freq = estimate_cpu_frequency();
 174
 175         printk("CPU frequency %d.%02d MHz\n", est_freq/1000000,
 176                (est_freq%1000000)*100/1000000);
 177
 178         cpu_khz = est_freq / 1000;
 179
 180         mips_scroll_message();
 181 #ifdef CONFIG_I8253             /* Only Malta has a PIT */
 182         setup_pit_timer();
 183 #endif
 184
 185         plat_perf_setup();
 186 }