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/libfdt.h>
  25 #include <linux/math64.h>
  26 #include <linux/sched.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/interrupt.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 #include <asm/mips-cps.h>
  43
  44 #include <asm/mips-boards/generic.h>
  45 #include <asm/mips-boards/maltaint.h>
  46
  47 static int mips_cpu_timer_irq;
  48 static int mips_cpu_perf_irq;
  49 extern int cp0_perfcount_irq;
  50
  51 static unsigned int gic_frequency;
  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 char secs1, secs2, ctrl;
  78         int secs;
  79         u64 giccount = 0, gicstart = 0;
  80
  81 #if defined(CONFIG_KVM_GUEST) && CONFIG_KVM_GUEST_TIMER_FREQ
  82         mips_hpt_frequency = CONFIG_KVM_GUEST_TIMER_FREQ * 1000000;
  83         return;
  84 #endif
  85
  86         local_irq_save(flags);
  87
  88         if (mips_gic_present())
  89                 clear_gic_config(GIC_CONFIG_COUNTSTOP);
  90
  91         /*
  92          * Read counters exactly on rising edge of update flag.
  93          * This helps get an accurate reading under virtualisation.
  94          */
  95         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
  96         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
  97         start = read_c0_count();
  98         if (mips_gic_present())
  99                 gicstart = read_gic_counter();
 100
 101         /* Wait for falling edge before reading RTC. */
 102         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 103         secs1 = CMOS_READ(RTC_SECONDS);
 104
 105         /* Read counters again exactly on rising edge of update flag. */
 106         while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
 107         count = read_c0_count();
 108         if (mips_gic_present())
 109                 giccount = read_gic_counter();
 110
 111         /* Wait for falling edge before reading RTC again. */
 112         while (CMOS_READ(RTC_REG_A) & RTC_UIP);
 113         secs2 = CMOS_READ(RTC_SECONDS);
 114
 115         ctrl = CMOS_READ(RTC_CONTROL);
 116
 117         local_irq_restore(flags);
 118
 119         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 120                 secs1 = bcd2bin(secs1);
 121                 secs2 = bcd2bin(secs2);
 122         }
 123         secs = secs2 - secs1;
 124         if (secs < 1)
 125                 secs += 60;
 126
 127         count -= start;
 128         count /= secs;
 129         mips_hpt_frequency = count;
 130
 131         if (mips_gic_present()) {
 132                 giccount = div_u64(giccount - gicstart, secs);
 133                 gic_frequency = giccount;
 134         }
 135 }
 136
 137 void read_persistent_clock(struct timespec *ts)
 138 {
 139         ts->tv_sec = mc146818_get_cmos_time();
 140         ts->tv_nsec = 0;
 141 }
 142
 143 int get_c0_fdc_int(void)
 144 {
 145         /*
 146          * Some cores claim the FDC is routable through the GIC, but it doesn't
 147          * actually seem to be connected for those Malta bitstreams.
 148          */
 149         switch (current_cpu_type()) {
 150         case CPU_INTERAPTIV:
 151         case CPU_PROAPTIV:
 152                 return -1;
 153         };
 154
 155         if (cpu_has_veic)
 156                 return -1;
 157         else if (mips_gic_present())
 158                 return gic_get_c0_fdc_int();
 159         else if (cp0_fdc_irq >= 0)
 160                 return MIPS_CPU_IRQ_BASE + cp0_fdc_irq;
 161         else
 162                 return -1;
 163 }
 164
 165 int get_c0_perfcount_int(void)
 166 {
 167         if (cpu_has_veic) {
 168                 set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 169                 mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
 170         } else if (mips_gic_present()) {
 171                 mips_cpu_perf_irq = gic_get_c0_perfcount_int();
 172         } else if (cp0_perfcount_irq >= 0) {
 173                 mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
 174         } else {
 175                 mips_cpu_perf_irq = -1;
 176         }
 177
 178         return mips_cpu_perf_irq;
 179 }
 180 EXPORT_SYMBOL_GPL(get_c0_perfcount_int);
 181
 182 unsigned int get_c0_compare_int(void)
 183 {
 184         if (cpu_has_veic) {
 185                 set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
 186                 mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
 187         } else if (mips_gic_present()) {
 188                 mips_cpu_timer_irq = gic_get_c0_compare_int();
 189         } else {
 190                 mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
 191         }
 192
 193         return mips_cpu_timer_irq;
 194 }
 195
 196 static void __init init_rtc(void)
 197 {
 198         unsigned char freq, ctrl;
 199
 200         /* Set 32KHz time base if not already set */
 201         freq = CMOS_READ(RTC_FREQ_SELECT);
 202         if ((freq & RTC_DIV_CTL) != RTC_REF_CLCK_32KHZ)
 203                 CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_FREQ_SELECT);
 204
 205         /* Ensure SET bit is clear so RTC can run */
 206         ctrl = CMOS_READ(RTC_CONTROL);
 207         if (ctrl & RTC_SET)
 208                 CMOS_WRITE(ctrl & ~RTC_SET, RTC_CONTROL);
 209 }
 210
 211 #ifdef CONFIG_CLKSRC_MIPS_GIC
 212 static u32 gic_frequency_dt;
 213
 214 static struct property gic_frequency_prop = {
 215         .name = "clock-frequency",
 216         .length = sizeof(u32),
 217         .value = &gic_frequency_dt,
 218 };
 219
 220 static void update_gic_frequency_dt(void)
 221 {
 222         struct device_node *node;
 223
 224         gic_frequency_dt = cpu_to_be32(gic_frequency);
 225
 226         node = of_find_compatible_node(NULL, NULL, "mti,gic-timer");
 227         if (!node) {
 228                 pr_err("mti,gic-timer device node not found\n");
 229                 return;
 230         }
 231
 232         if (of_update_property(node, &gic_frequency_prop) < 0)
 233                 pr_err("error updating gic frequency property\n");
 234 }
 235
 236 #endif
 237
 238 void __init plat_time_init(void)
 239 {
 240         unsigned int prid = read_c0_prid() & (PRID_COMP_MASK | PRID_IMP_MASK);
 241         unsigned int freq;
 242
 243         init_rtc();
 244         estimate_frequencies();
 245
 246         freq = mips_hpt_frequency;
 247         if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
 248             (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
 249                 freq *= 2;
 250         freq = freqround(freq, 5000);
 251         printk("CPU frequency %d.%02d MHz\n", freq/1000000,
 252                (freq%1000000)*100/1000000);
 253
 254         mips_scroll_message();
 255
 256 #ifdef CONFIG_I8253
 257         /* Only Malta has a PIT. */
 258         setup_pit_timer();
 259 #endif
 260
 261         if (mips_gic_present()) {
 262                 freq = freqround(gic_frequency, 5000);
 263                 printk("GIC frequency %d.%02d MHz\n", freq/1000000,
 264                        (freq%1000000)*100/1000000);
 265 #ifdef CONFIG_CLKSRC_MIPS_GIC
 266                 update_gic_frequency_dt();
 267                 timer_probe();
 268 #endif
 269         }
 270 }