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/cpu.h>
  31 #include <asm/mipsregs.h>
  32 #include <asm/mipsmtregs.h>
  33 #include <asm/hardirq.h>
  34 #include <asm/irq.h>
  35 #include <asm/div64.h>
  36 #include <asm/setup.h>
  37 #include <asm/time.h>
  38 #include <asm/mc146818-time.h>
  39 #include <asm/msc01_ic.h>
  40 #include <asm/gic.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 void mips_timer_dispatch(void)
  50 {
  51         do_IRQ(mips_cpu_timer_irq);
  52 }
  53
  54 static void mips_perf_dispatch(void)
  55 {
  56         do_IRQ(mips_cpu_perf_irq);
  57 }
  58
  59 static unsigned int freqround(unsigned int freq, unsigned int amount)
  60 {
  61         freq += amount;
  62         freq -= freq % (amount*2);
  63         return freq;
  64 }
  65
  66 /*
  67  * Estimate CPU and GIC frequencies.
  68  */
  69 static void __init estimate_frequencies(void)
  70 {
  71         unsigned long flags;
  72         unsigned int count, start;
  73 #ifdef CONFIG_IRQ_GIC
  74         unsigned int giccount = 0, gicstart = 0;
  75 #endif
  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 #ifdef CONFIG_IRQ_GIC
  91         if (gic_present)
  92                 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), gicstart);
  93 #endif
  94
  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));
  98
  99         count = read_c0_count();
 100 #ifdef CONFIG_IRQ_GIC
 101         if (gic_present)
 102                 GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), giccount);
 103 #endif
 104
 105         local_irq_restore(flags);
 106
 107         count -= start;
 108         mips_hpt_frequency = count;
 109
 110 #ifdef CONFIG_IRQ_GIC
 111         if (gic_present) {
 112                 giccount -= gicstart;
 113                 gic_frequency = giccount;
 114         }
 115 #endif
 116 }
 117
 118 void read_persistent_clock(struct timespec *ts)
 119 {
 120         ts->tv_sec = mc146818_get_cmos_time();
 121         ts->tv_nsec = 0;
 122 }
 123
 124 static void __init plat_perf_setup(void)
 125 {
 126 #ifdef MSC01E_INT_BASE
 127         if (cpu_has_veic) {
 128                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 129                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 130         } else
 131 #endif
 132         if (cp0_perfcount_irq >= 0) {
 133                 if (cpu_has_vint)
 134                         set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
 135                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 136 #ifdef CONFIG_SMP
 137                 irq_set_handler(mips_cpu_perf_irq, handle_percpu_irq);
 138 #endif
 139         }
 140 }
 141
 142 unsigned int get_c0_compare_int(void)
 143 {
 144 #ifdef MSC01E_INT_BASE
 145         if (cpu_has_veic) {
 146                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 147                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 148         } else
 149 #endif
 150         {
 151                 if (cpu_has_vint)
 152                         set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
 153                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 154         }
 155
 156         return mips_cpu_timer_irq;
 157 }
 158
 159 static void __init init_rtc(void)
 160 {
 161         /* stop the clock whilst setting it up */
 162         CMOS_WRITE(RTC_SET | RTC_24H, RTC_CONTROL);
 163
 164         /* 32KHz time base */
 165         CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
 166
 167         /* start the clock */
 168         CMOS_WRITE(RTC_24H, RTC_CONTROL);
 169 }
 170
 171 void __init plat_time_init(void)
 172 {
 173         unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
 174         unsigned int freq;
 175
 176         init_rtc();
 177         estimate_frequencies();
 178
 179         freq = mips_hpt_frequency;
 180         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 181             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 182                 freq *= 2;
 183         freq = freqround(freq, 5000);
 184         printk("CPU frequency %d.%02d MHz\n", freq/1000000,
 185                (freq%1000000)*100/1000000);
 186
 187         mips_scroll_message();
 188
 189 #ifdef CONFIG_I8253
 190         /* Only Malta has a PIT. */
 191         setup_pit_timer();
 192 #endif
 193
 194 #ifdef CONFIG_IRQ_GIC
 195         if (gic_present) {
 196                 freq = freqround(gic_frequency, 5000);
 197                 printk("GIC frequency %d.%02d MHz\n", freq/1000000,
 198                        (freq%1000000)*100/1000000);
 199 #ifdef CONFIG_CSRC_GIC
 200                 gic_clocksource_init(gic_frequency);
 201 #endif
 202         }
 203 #endif
 204
 205         plat_perf_setup();
 206 }