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/*
 * Arm SSE Subsystem System Timer
 *
 * Copyright (c) 2020 Linaro Limited
 * Written by Peter Maydell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 or
 * (at your option) any later version.
 */

/*
 * This is a model of the "System timer" which is documented in
 * the Arm SSE-123 Example Subsystem Technical Reference Manual:
 * https://developer.arm.com/documentation/101370/latest/
 *
 * QEMU interface:
 *  + Clock input "CLK": clock
 *  + sysbus MMIO region 0: the register bank
 *  + sysbus IRQ 0: timer interrupt
 */

#ifndef SSE_TIMER_H
#define SSE_TIMER_H

#include "hw/sysbus.h"
#include "qom/object.h"

#define TYPE_SSE_TIMER "sse-timer"
OBJECT_DECLARE_SIMPLE_TYPE(SSETimer, SSE_TIMER)

struct SSETimer {
    /*< private >*/
    SysBusDevice parent_obj;

    /*< public >*/
    MemoryRegion iomem;
    qemu_irq irq;
    Clock *clk;
    QEMUTimer timer;

    uint32_t cntfrq;
    uint32_t cntp_ctl;
    uint64_t cntp_cval;
    uint64_t cntp_aival;
    uint32_t cntp_aival_ctl;
    uint32_t cntp_aival_reload;

    /*
     * These are used for handling clock frequency changes: they are a
     * tuple of (QEMU_CLOCK_VIRTUAL timestamp, CNTPCT at that time),
     * taken when the clock frequency changes. sse_cntpct() needs them
     * to calculate the current CNTPCT.
     */
    uint64_t ns_then;
    uint64_t ticks_then;
};

#endif