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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/mips/kernel/cevt-sb1250.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * Copyright (C) 2000, 2001 Broadcom Corporation

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 */

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#include <linux/clockchips.h>

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#include <linux/interrupt.h>

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#include <linux/irq.h>

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#include <linux/percpu.h>

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#include <linux/smp.h>

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#include <asm/addrspace.h>

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#include <asm/io.h>

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#include <asm/time.h>

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#include <asm/sibyte/sb1250.h>

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#include <asm/sibyte/sb1250_regs.h>

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#include <asm/sibyte/sb1250_int.h>

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#include <asm/sibyte/sb1250_scd.h>

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#define IMR_IP2_VAL	K_INT_MAP_I0

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#define IMR_IP3_VAL	K_INT_MAP_I1

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#define IMR_IP4_VAL	K_INT_MAP_I2

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/*

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 * The general purpose timer ticks at 1MHz independent if

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 * the rest of the system

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 */

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static int sibyte_shutdown(struct clock_event_device *evt)

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{

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	void __iomem *cfg;

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	cfg = IOADDR(A_SCD_TIMER_REGISTER(smp_processor_id(), R_SCD_TIMER_CFG));

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	/* Stop the timer until we actually program a shot */

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	__raw_writeq(0, cfg);

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	return 0;

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}

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static int sibyte_set_periodic(struct clock_event_device *evt)

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{

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	unsigned int cpu = smp_processor_id();

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	void __iomem *cfg, *init;

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	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));

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	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

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	__raw_writeq(0, cfg);

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	__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);

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	__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, cfg);

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	return 0;

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}

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static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)

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{

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	unsigned int cpu = smp_processor_id();

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	void __iomem *cfg, *init;

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	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));

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	init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));

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	__raw_writeq(0, cfg);

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	__raw_writeq(delta - 1, init);

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	__raw_writeq(M_SCD_TIMER_ENABLE, cfg);

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	return 0;

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}

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static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)

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{

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	unsigned int cpu = smp_processor_id();

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	struct clock_event_device *cd = dev_id;

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	void __iomem *cfg;

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	unsigned long tmode;

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	if (clockevent_state_periodic(cd))

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		tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;

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	else

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		tmode = 0;

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	/* ACK interrupt */

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	cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));

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	____raw_writeq(tmode, cfg);

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	cd->event_handler(cd);

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	return IRQ_HANDLED;

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}

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static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);

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static DEFINE_PER_CPU(char [18], sibyte_hpt_name);

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void sb1250_clockevent_init(void)

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{

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	unsigned int cpu = smp_processor_id();

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	unsigned int irq = K_INT_TIMER_0 + cpu;

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	struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);

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	unsigned char *name = per_cpu(sibyte_hpt_name, cpu);

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	unsigned long flags = IRQF_PERCPU | IRQF_TIMER;

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	/* Only have 4 general purpose timers, and we use last one as hpt */

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	BUG_ON(cpu > 2);

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	sprintf(name, "sb1250-counter-%d", cpu);

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	cd->name		= name;

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	cd->features		= CLOCK_EVT_FEAT_PERIODIC |

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				  CLOCK_EVT_FEAT_ONESHOT;

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	clockevent_set_clock(cd, V_SCD_TIMER_FREQ);

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	cd->max_delta_ns	= clockevent_delta2ns(0x7fffff, cd);

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	cd->max_delta_ticks	= 0x7fffff;

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	cd->min_delta_ns	= clockevent_delta2ns(2, cd);

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	cd->min_delta_ticks	= 2;

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	cd->rating		= 200;

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	cd->irq			= irq;

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	cd->cpumask		= cpumask_of(cpu);

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	cd->set_next_event	= sibyte_next_event;

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	cd->set_state_shutdown	= sibyte_shutdown;

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	cd->set_state_periodic	= sibyte_set_periodic;

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	cd->set_state_oneshot	= sibyte_shutdown;

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	clockevents_register_device(cd);

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	sb1250_mask_irq(cpu, irq);

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	/*

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	 * Map the timer interrupt to IP[4] of this cpu

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	 */

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	__raw_writeq(IMR_IP4_VAL,

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		     IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +

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			    (irq << 3)));

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	sb1250_unmask_irq(cpu, irq);

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	irq_set_affinity(irq, cpumask_of(cpu));

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	if (request_irq(irq, sibyte_counter_handler, flags, name, cd))

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		pr_err("Failed to request irq %d (%s)\n", irq, name);

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}

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