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/math64.h>
  25 #include <linux/sched.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/irqchip/mips-gic.h>
  29 #include <linux/timex.h>
  30 #include <linux/mc146818rtc.h>
  31
  32 #include <asm/cpu.h>
  33 #include <asm/mipsregs.h>
  34 #include <asm/mipsmtregs.h>
  35 #include <asm/hardirq.h>
  36 #include <asm/irq.h>
  37 #include <asm/div64.h>
  38 #include <asm/setup.h>
  39 #include <asm/time.h>
  40 #include <asm/mc146818-time.h>
  41 #include <asm/msc01_ic.h>
  42
  43 #include <asm/mips-boards/generic.h>
  44 #include <asm/mips-boards/maltaint.h>
  45
  46 static int mips_cpu_timer_irq;
  47 static int mips_cpu_perf_irq;
  48 extern int cp0_perfcount_irq;
  49
  50 static unsigned int gic_frequency;
  51
  52 static void mips_timer_dispatch(void)
  53 {
  54         do_IRQ(mips_cpu_timer_irq);
  55 }
  56
  57 static void mips_perf_dispatch(void)
  58 {
  59         do_IRQ(mips_cpu_perf_irq);
  60 }
  61
  62 static unsigned int freqround(unsigned int freq, unsigned int amount)
  63 {
  64         freq += amount;
  65         freq -= freq % (amount*2);
  66         return freq;
  67 }
  68
  69 /*
  70  * Estimate CPU and GIC frequencies.
  71  */
  72 static void __init estimate_frequencies(void)
  73 {
  74         unsigned long flags;
  75         unsigned int count, start;
  76         unsigned char secs1, secs2, ctrl;
  77         int secs;
  78         cycle_t giccount = 0, gicstart = 0;
  79
  80 #if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
  81         mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
  82         return;
  83 #endif
  84
  85         local_irq_save(flags);
  86
  87         if (gic_present)
  88                 gic_start_count();
  89
  90         /*
  91          * Read counters exactly on rising edge of update flag.
  92          * This helps get an accurate reading under virtualisation.
  93          */
  94         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
  95         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
  96         start = read_c0_count();
  97         if (gic_present)
  98                 gicstart = gic_read_count();
  99
 100         /* Wait for falling edge before reading RTC. */
 101         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 102         secs1 = CMOS_READ(RTC_SECONDS);
 103
 104         /* Read counters again exactly on rising edge of update flag. */
 105         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
 106         count = read_c0_count();
 107         if (gic_present)
 108                 giccount = gic_read_count();
 109
 110         /* Wait for falling edge before reading RTC again. */
 111         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 112         secs2 = CMOS_READ(RTC_SECONDS);
 113
 114         ctrl = CMOS_READ(RTC_CONTROL);
 115
 116         local_irq_restore(flags);
 117
 118         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 119                 secs1 = bcd2bin(secs1);
 120                 secs2 = bcd2bin(secs2);
 121         }
 122         secs = secs2 - secs1;
 123         if (secs < 1)
 124                 secs += 60;
 125
 126         count -= start;
 127         count /= secs;
 128         mips_hpt_frequency = count;
 129
 130         if (gic_present) {
 131                 giccount = div_u64(giccount - gicstart, secs);
 132                 gic_frequency = giccount;
 133         }
 134 }
 135
 136 void read_persistent_clock(struct timespec *ts)
 137 {
 138         ts->tv_sec = mc146818_get_cmos_time();
 139         ts->tv_nsec = 0;
 140 }
 141
 142 int get_c0_fdc_int(void)
 143 {
 144         /*
 145          * Some cores claim the FDC is routable through the GIC, but it doesn't
 146          * actually seem to be connected for those Malta bitstreams.
 147          */
 148         switch (current_cpu_type()) {
 149         case CPU_INTERAPTIV:
 150         case CPU_PROAPTIV:
 151                 return -1;
 152         };
 153
 154         if (cpu_has_veic)
 155                 return -1;
 156         else if (gic_present)
 157                 return gic_get_c0_fdc_int();
 158         else if (cp0_fdc_irq >= 0)
 159                 return MIPS_CPU_IRQ_BASE + cp0_fdc_irq;
 160         else
 161                 return -1;
 162 }
 163
 164 int get_c0_perfcount_int(void)
 165 {
 166         if (cpu_has_veic) {
 167                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 168                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 169         } else if (gic_present) {
 170                 mips_cpu_perf_irq = gic_get_c0_perfcount_int();
 171         } else if (cp0_perfcount_irq >= 0) {
 172                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 173         } else {
 174                 mips_cpu_perf_irq = -1;
 175         }
 176
 177         return mips_cpu_perf_irq;
 178 }
 179 EXPORT_SYMBOL_GPL(get_c0_perfcount_int);
 180
 181 unsigned int get_c0_compare_int(void)
 182 {
 183         if (cpu_has_veic) {
 184                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 185                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 186         } else if (gic_present) {
 187                 mips_cpu_timer_irq = gic_get_c0_compare_int();
 188         } else {
 189                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 190         }
 191
 192         return mips_cpu_timer_irq;
 193 }
 194
 195 static void __init init_rtc(void)
 196 {
 197         unsigned char freq, ctrl;
 198
 199         /* Set 32KHz time base if not already set */
 200         freq = CMOS_READ(RTC_FREQ_SELECT);
 201         if ((freq & RTC_DIV_CTL) != RTC_REF_CLCK_32KHZ)
 202                 CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
 203
 204         /* Ensure SET bit is clear so RTC can run */
 205         ctrl = CMOS_READ(RTC_CONTROL);
 206         if (ctrl & RTC_SET)
 207                 CMOS_WRITE(ctrl & ~RTC_SET, RTC_CONTROL);
 208 }
 209
 210 void __init plat_time_init(void)
 211 {
 212         unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
 213         unsigned int freq;
 214
 215         init_rtc();
 216         estimate_frequencies();
 217
 218         freq = mips_hpt_frequency;
 219         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 220             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 221                 freq *= 2;
 222         freq = freqround(freq, 5000);
 223         printk("CPU frequency %d.%02d MHz\n", freq/1000000,
 224                (freq%1000000)*100/1000000);
 225
 226         mips_scroll_message();
 227
 228 #ifdef CONFIG_I8253
 229         /* Only Malta has a PIT. */
 230         setup_pit_timer();
 231 #endif
 232
 233 #ifdef CONFIG_MIPS_GIC
 234         if (gic_present) {
 235                 freq = freqround(gic_frequency, 5000);
 236                 printk("GIC frequency %d.%02d MHz\n", freq/1000000,
 237                        (freq%1000000)*100/1000000);
 238 #ifdef CONFIG_CLKSRC_MIPS_GIC
 239                 gic_clocksource_init(gic_frequency);
 240 #endif
 241         }
 242 #endif
 243 }