kernel/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                 gic_start_count();
  92                 gicstart = gic_read_count();
  93         }
  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         if (gic_present)
 101                 giccount = gic_read_count();
 102
 103         local_irq_restore(flags);
 104
 105         count -= start;
 106         mips_hpt_frequency = count;
 107
 108         if (gic_present) {
 109                 giccount -= gicstart;
 110                 gic_frequency = giccount;
 111         }
 112 }
 113
 114 void read_persistent_clock(struct timespec *ts)
 115 {
 116         ts->tv_sec = mc146818_get_cmos_time();
 117         ts->tv_nsec = 0;
 118 }
 119
 120 int get_c0_fdc_int(void)
 121 {
 122         int mips_cpu_fdc_irq;
 123
 124         if (cpu_has_veic)
 125                 mips_cpu_fdc_irq = -1;
 126         else if (gic_present)
 127                 mips_cpu_fdc_irq = gic_get_c0_fdc_int();
 128         else if (cp0_fdc_irq >= 0)
 129                 mips_cpu_fdc_irq = MIPS_CPU_IRQ_BASE + cp0_fdc_irq;
 130         else
 131                 mips_cpu_fdc_irq = -1;
 132
 133         return mips_cpu_fdc_irq;
 134 }
 135
 136 int get_c0_perfcount_int(void)
 137 {
 138         if (cpu_has_veic) {
 139                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 140                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 141         } else if (gic_present) {
 142                 mips_cpu_perf_irq = gic_get_c0_perfcount_int();
 143         } else if (cp0_perfcount_irq >= 0) {
 144                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 145         } else {
 146                 mips_cpu_perf_irq = -1;
 147         }
 148
 149         return mips_cpu_perf_irq;
 150 }
 151 EXPORT_SYMBOL_GPL(get_c0_perfcount_int);
 152
 153 unsigned int get_c0_compare_int(void)
 154 {
 155         if (cpu_has_veic) {
 156                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 157                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 158         } else if (gic_present) {
 159                 mips_cpu_timer_irq = gic_get_c0_compare_int();
 160         } else {
 161                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 162         }
 163
 164         return mips_cpu_timer_irq;
 165 }
 166
 167 static void __init init_rtc(void)
 168 {
 169         unsigned char freq, ctrl;
 170
 171         /* Set 32KHz time base if not already set */
 172         freq = CMOS_READ(RTC_FREQ_SELECT);
 173         if ((freq & RTC_DIV_CTL) != RTC_REF_CLCK_32KHZ)
 174                 CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
 175
 176         /* Ensure SET bit is clear so RTC can run */
 177         ctrl = CMOS_READ(RTC_CONTROL);
 178         if (ctrl & RTC_SET)
 179                 CMOS_WRITE(ctrl & ~RTC_SET, RTC_CONTROL);
 180 }
 181
 182 void __init plat_time_init(void)
 183 {
 184         unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
 185         unsigned int freq;
 186
 187         init_rtc();
 188         estimate_frequencies();
 189
 190         freq = mips_hpt_frequency;
 191         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 192             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 193                 freq *= 2;
 194         freq = freqround(freq, 5000);
 195         printk("CPU frequency %d.%02d MHz\n", freq/1000000,
 196                (freq%1000000)*100/1000000);
 197
 198         mips_scroll_message();
 199
 200 #ifdef CONFIG_I8253
 201         /* Only Malta has a PIT. */
 202         setup_pit_timer();
 203 #endif
 204
 205 #ifdef CONFIG_MIPS_GIC
 206         if (gic_present) {
 207                 freq = freqround(gic_frequency, 5000);
 208                 printk("GIC frequency %d.%02d MHz\n", freq/1000000,
 209                        (freq%1000000)*100/1000000);
 210 #ifdef CONFIG_CLKSRC_MIPS_GIC
 211                 gic_clocksource_init(gic_frequency);
 212 #endif
 213         }
 214 #endif
 215 }