526a677069
It's running early during the bootup process so interrupts are still off. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/kernel_stat.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/mc146818rtc.h>
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#include <linux/smp.h>
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#include <linux/timex.h>
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#include <asm/hardirq.h>
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#include <asm/div64.h>
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#include <asm/cpu.h>
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#include <asm/time.h>
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#include <asm/irq.h>
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#include <asm/mc146818-time.h>
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#include <asm/msc01_ic.h>
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#include <asm/mips-boards/generic.h>
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#include <asm/mips-boards/prom.h>
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#include <asm/mips-boards/simint.h>
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unsigned long cpu_khz;
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/*
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* Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect
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*/
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static unsigned int __init estimate_cpu_frequency(void)
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{
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unsigned int prid = read_c0_prid() & 0xffff00;
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unsigned int count;
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#if 1
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/*
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* hardwire the board frequency to 12MHz.
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*/
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if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
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(prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
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count = 12000000;
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else
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count = 6000000;
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#else
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unsigned int flags;
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local_irq_save(flags);
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/* Start counter exactly on falling edge of update flag */
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while (CMOS_READ(RTC_REG_A) & RTC_UIP);
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while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
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/* Start r4k counter. */
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write_c0_count(0);
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/* Read counter exactly on falling edge of update flag */
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while (CMOS_READ(RTC_REG_A) & RTC_UIP);
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while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
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count = read_c0_count();
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/* restore interrupts */
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local_irq_restore(flags);
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#endif
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mips_hpt_frequency = count;
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if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
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(prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
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count *= 2;
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count += 5000; /* round */
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count -= count%10000;
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return count;
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}
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static int mips_cpu_timer_irq;
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static void mips_timer_dispatch(void)
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{
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do_IRQ(mips_cpu_timer_irq);
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}
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unsigned __init get_c0_compare_int(void)
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{
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#ifdef MSC01E_INT_BASE
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if (cpu_has_veic) {
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set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
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mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
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} else {
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#endif
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if (cpu_has_vint)
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set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
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mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
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}
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return mips_cpu_timer_irq;
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}
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void __init plat_time_init(void)
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{
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unsigned int est_freq;
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/* Set Data mode - binary. */
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CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
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est_freq = estimate_cpu_frequency();
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printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000,
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(est_freq % 1000000) * 100 / 1000000);
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cpu_khz = est_freq / 1000;
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}
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