cregit-Linux how code gets into the kernel

Release 4.18 arch/openrisc/kernel/time.c

/*
 * OpenRISC time.c
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * Modifications for the OpenRISC architecture:
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/interrupt.h>
#include <linux/ftrace.h>

#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/irq.h>
#include <linux/io.h>

#include <asm/cpuinfo.h>

/* Test the timer ticks to count, used in sync routine */

inline void openrisc_timer_set(unsigned long count) { mtspr(SPR_TTCR, count); }

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Stafford Horne17100.00%1100.00%
Total17100.00%1100.00%

/* Set the timer to trigger in delta cycles */
inline void openrisc_timer_set_next(unsigned long delta) { u32 c; /* Read 32-bit counter value, add delta, mask off the low 28 bits. * We're guaranteed delta won't be bigger than 28 bits because the * generic timekeeping code ensures that for us. */ c = mfspr(SPR_TTCR); c += delta; c &= SPR_TTMR_TP; /* Set counter and enable interrupt. * Keep timer in continuous mode always. */ mtspr(SPR_TTMR, SPR_TTMR_CR | SPR_TTMR_IE | c); }

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Jonas Bonn3790.24%150.00%
Stafford Horne49.76%150.00%
Total41100.00%2100.00%


static int openrisc_timer_set_next_event(unsigned long delta, struct clock_event_device *dev) { openrisc_timer_set_next(delta); return 0; }

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Stafford Horne1982.61%150.00%
Jonas Bonn417.39%150.00%
Total23100.00%2100.00%

/* This is the clock event device based on the OR1K tick timer. * As the timer is being used as a continuous clock-source (required for HR * timers) we cannot enable the PERIODIC feature. The tick timer can run using * one-shot events, so no problem. */ DEFINE_PER_CPU(struct clock_event_device, clockevent_openrisc_timer);
void openrisc_clockevent_init(void) { unsigned int cpu = smp_processor_id(); struct clock_event_device *evt = &per_cpu(clockevent_openrisc_timer, cpu); struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[cpu]; mtspr(SPR_TTMR, SPR_TTMR_CR); #ifdef CONFIG_SMP evt->broadcast = tick_broadcast; #endif evt->name = "openrisc_timer_clockevent", evt->features = CLOCK_EVT_FEAT_ONESHOT, evt->rating = 300, evt->set_next_event = openrisc_timer_set_next_event, evt->cpumask = cpumask_of(cpu); /* We only have 28 bits */ clockevents_config_and_register(evt, cpuinfo->clock_frequency, 100, 0x0fffffff); }

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Stefan Kristiansson8784.47%150.00%
Jonas Bonn1615.53%150.00%
Total103100.00%2100.00%


static inline void timer_ack(void) { /* Clear the IP bit and disable further interrupts */ /* This can be done very simply... we just need to keep the timer running, so just maintain the CR bits while clearing the rest of the register */ mtspr(SPR_TTMR, SPR_TTMR_CR); }

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Jonas Bonn18100.00%1100.00%
Total18100.00%1100.00%

/* * The timer interrupt is mostly handled in generic code nowadays... this * function just acknowledges the interrupt and fires the event handler that * has been set on the clockevent device by the generic time management code. * * This function needs to be called by the timer exception handler and that's * all the exception handler needs to do. */
irqreturn_t __irq_entry timer_interrupt(struct pt_regs *regs) { struct pt_regs *old_regs = set_irq_regs(regs); unsigned int cpu = smp_processor_id(); struct clock_event_device *evt = &per_cpu(clockevent_openrisc_timer, cpu); timer_ack(); /* * update_process_times() expects us to have called irq_enter(). */ irq_enter(); evt->event_handler(evt); irq_exit(); set_irq_regs(old_regs); return IRQ_HANDLED; }

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PersonTokensPropCommitsCommitProp
Jonas Bonn5481.82%150.00%
Stefan Kristiansson1218.18%150.00%
Total66100.00%2100.00%

/** * Clocksource: Based on OpenRISC timer/counter * * This sets up the OpenRISC Tick Timer as a clock source. The tick timer * is 32 bits wide and runs at the CPU clock frequency. */
static u64 openrisc_timer_read(struct clocksource *cs) { return (u64) mfspr(SPR_TTCR); }

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Jonas Bonn1890.00%150.00%
Thomas Gleixner210.00%150.00%
Total20100.00%2100.00%

static struct clocksource openrisc_timer = { .name = "openrisc_timer", .rating = 200, .read = openrisc_timer_read, .mask = CLOCKSOURCE_MASK(32), .flags = CLOCK_SOURCE_IS_CONTINUOUS, };
static int __init openrisc_timer_init(void) { struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()]; if (clocksource_register_hz(&openrisc_timer, cpuinfo->clock_frequency)) panic("failed to register clocksource"); /* Enable the incrementer: 'continuous' mode with interrupt disabled */ mtspr(SPR_TTMR, SPR_TTMR_CR); return 0; }

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PersonTokensPropCommitsCommitProp
Jonas Bonn3673.47%150.00%
Stefan Kristiansson1326.53%150.00%
Total49100.00%2100.00%


void __init time_init(void) { u32 upr; upr = mfspr(SPR_UPR); if (!(upr & SPR_UPR_TTP)) panic("Linux not supported on devices without tick timer"); openrisc_timer_init(); openrisc_clockevent_init(); }

Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn38100.00%1100.00%
Total38100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn29063.88%125.00%
Stefan Kristiansson12026.43%125.00%
Stafford Horne429.25%125.00%
Thomas Gleixner20.44%125.00%
Total454100.00%4100.00%
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