/* * Carsten Langgaard, carstenl@mips.com * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. * * This program is free software; you can distribute it and/or modify it * under the terms of the GNU General Public License (Version 2) as * published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. * * Setting up the clock on the MIPS boards. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_MIPS_ATLAS #include #endif #ifdef CONFIG_MIPS_MALTA #include #endif #ifdef CONFIG_MIPS_SEAD #include #endif unsigned long cpu_khz; static int mips_cpu_timer_irq; extern int cp0_perfcount_irq; extern void smtc_timer_broadcast(void); static void mips_timer_dispatch(void) { do_IRQ(mips_cpu_timer_irq); } static void mips_perf_dispatch(void) { do_IRQ(cp0_perfcount_irq); } /* * Redeclare until I get around mopping the timer code insanity on MIPS. */ extern int null_perf_irq(void); extern int (*perf_irq)(void); /* * Possibly handle a performance counter interrupt. * Return true if the timer interrupt should not be checked */ static inline int handle_perf_irq (int r2) { /* * The performance counter overflow interrupt may be shared with the * timer interrupt (cp0_perfcount_irq < 0). If it is and a * performance counter has overflowed (perf_irq() == IRQ_HANDLED) * and we can't reliably determine if a counter interrupt has also * happened (!r2) then don't check for a timer interrupt. */ return (cp0_perfcount_irq < 0) && perf_irq() == IRQ_HANDLED && !r2; } irqreturn_t mips_timer_interrupt(int irq, void *dev_id) { int cpu = smp_processor_id(); #ifdef CONFIG_MIPS_MT_SMTC /* * In an SMTC system, one Count/Compare set exists per VPE. * Which TC within a VPE gets the interrupt is essentially * random - we only know that it shouldn't be one with * IXMT set. Whichever TC gets the interrupt needs to * send special interprocessor interrupts to the other * TCs to make sure that they schedule, etc. * * That code is specific to the SMTC kernel, not to * the a particular platform, so it's invoked from * the general MIPS timer_interrupt routine. */ /* * We could be here due to timer interrupt, * perf counter overflow, or both. */ (void) handle_perf_irq(1); if (read_c0_cause() & (1 << 30)) { /* * There are things we only want to do once per tick * in an "MP" system. One TC of each VPE will take * the actual timer interrupt. The others will get * timer broadcast IPIs. We use whoever it is that takes * the tick on VPE 0 to run the full timer_interrupt(). */ if (cpu_data[cpu].vpe_id == 0) { timer_interrupt(irq, NULL); } else { write_c0_compare(read_c0_count() + (mips_hpt_frequency/HZ)); local_timer_interrupt(irq, dev_id); } smtc_timer_broadcast(); } #else /* CONFIG_MIPS_MT_SMTC */ int r2 = cpu_has_mips_r2; if (handle_perf_irq(r2)) goto out; if (r2 && ((read_c0_cause() & (1 << 30)) == 0)) goto out; if (cpu == 0) { /* * CPU 0 handles the global timer interrupt job and process * accounting resets count/compare registers to trigger next * timer int. */ timer_interrupt(irq, NULL); } else { /* Everyone else needs to reset the timer int here as ll_local_timer_interrupt doesn't */ /* * FIXME: need to cope with counter underflow. * More support needs to be added to kernel/time for * counter/timer interrupts on multiple CPU's */ write_c0_compare(read_c0_count() + (mips_hpt_frequency/HZ)); /* * Other CPUs should do profiling and process accounting */ local_timer_interrupt(irq, dev_id); } out: #endif /* CONFIG_MIPS_MT_SMTC */ return IRQ_HANDLED; } /* * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect */ static unsigned int __init estimate_cpu_frequency(void) { unsigned int prid = read_c0_prid() & 0xffff00; unsigned int count; #if defined(CONFIG_MIPS_SEAD) || defined(CONFIG_MIPS_SIM) /* * The SEAD board doesn't have a real time clock, so we can't * really calculate the timer frequency * For now we hardwire the SEAD board frequency to 12MHz. */ if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) || (prid == (PRID_COMP_MIPS | PRID_IMP_25KF))) count = 12000000; else count = 6000000; #endif #if defined(CONFIG_MIPS_ATLAS) || defined(CONFIG_MIPS_MALTA) unsigned long flags; unsigned int start; local_irq_save(flags); /* Start counter exactly on falling edge of update flag */ while (CMOS_READ(RTC_REG_A) & RTC_UIP); while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); /* Start r4k counter. */ start = read_c0_count(); /* Read counter exactly on falling edge of update flag */ while (CMOS_READ(RTC_REG_A) & RTC_UIP); while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); count = read_c0_count() - start; /* restore interrupts */ local_irq_restore(flags); #endif mips_hpt_frequency = count; if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) && (prid != (PRID_COMP_MIPS | PRID_IMP_25KF))) count *= 2; count += 5000; /* round */ count -= count%10000; return count; } unsigned long read_persistent_clock(void) { return mc146818_get_cmos_time(); } void __init plat_time_init(void) { unsigned int est_freq; /* Set Data mode - binary. */ CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL); est_freq = estimate_cpu_frequency (); printk("CPU frequency %d.%02d MHz\n", est_freq/1000000, (est_freq%1000000)*100/1000000); cpu_khz = est_freq / 1000; mips_scroll_message(); } irqreturn_t mips_perf_interrupt(int irq, void *dev_id) { return perf_irq(); } static struct irqaction perf_irqaction = { .handler = mips_perf_interrupt, .flags = IRQF_DISABLED | IRQF_PERCPU, .name = "performance", }; void __init plat_perf_setup(struct irqaction *irq) { cp0_perfcount_irq = -1; #ifdef MSC01E_INT_BASE if (cpu_has_veic) { set_vi_handler (MSC01E_INT_PERFCTR, mips_perf_dispatch); cp0_perfcount_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR; } else #endif if (cp0_perfcount_irq >= 0) { if (cpu_has_vint) set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch); #ifdef CONFIG_MIPS_MT_SMTC setup_irq_smtc(cp0_perfcount_irq, irq, 0x100 << cp0_perfcount_irq); #else setup_irq(cp0_perfcount_irq, irq); #endif /* CONFIG_MIPS_MT_SMTC */ #ifdef CONFIG_SMP set_irq_handler(cp0_perfcount_irq, handle_percpu_irq); #endif } } void __init plat_timer_setup(struct irqaction *irq) { #ifdef MSC01E_INT_BASE if (cpu_has_veic) { set_vi_handler (MSC01E_INT_CPUCTR, mips_timer_dispatch); mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR; } else #endif { if (cpu_has_vint) set_vi_handler(cp0_compare_irq, mips_timer_dispatch); mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq; } /* we are using the cpu counter for timer interrupts */ irq->handler = mips_timer_interrupt; /* we use our own handler */ #ifdef CONFIG_MIPS_MT_SMTC setup_irq_smtc(mips_cpu_timer_irq, irq, 0x100 << cp0_compare_irq); #else setup_irq(mips_cpu_timer_irq, irq); #endif /* CONFIG_MIPS_MT_SMTC */ #ifdef CONFIG_SMP set_irq_handler(mips_cpu_timer_irq, handle_percpu_irq); #endif plat_perf_setup(&perf_irqaction); }