linux-imx

/*

 * J-Core SoC PIT/clocksource driver

 *

 * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 */

​

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/interrupt.h>

#include <linux/clockchips.h>

#include <linux/clocksource.h>

#include <linux/sched_clock.h>

#include <linux/cpu.h>

#include <linux/cpuhotplug.h>

#include <linux/of_address.h>

#include <linux/of_irq.h>

​

#define PIT_IRQ_SHIFT       12

#define PIT_PRIO_SHIFT      20

#define PIT_ENABLE_SHIFT    26

#define PIT_PRIO_MASK       0xf

​

#define REG_PITEN       0x00

#define REG_THROT       0x10

#define REG_COUNT       0x14

#define REG_BUSPD       0x18

#define REG_SECHI       0x20

#define REG_SECLO       0x24

#define REG_NSEC        0x28

​

struct jcore_pit {

    struct clock_event_device   ced;

    void __iomem            *base;

    unsigned long           periodic_delta;

    u32             enable_val;

};

​

static void __iomem *jcore_pit_base;

static struct jcore_pit __percpu *jcore_pit_percpu;

​

static notrace u64 jcore_sched_clock_read(void)

{

    u32 seclo, nsec, seclo0;

    __iomem void *base = jcore_pit_base;

​

    seclo = readl(base + REG_SECLO);

    do {

        seclo0 = seclo;

        nsec  = readl(base + REG_NSEC);

        seclo = readl(base + REG_SECLO);

    } while (seclo0 != seclo);

​

    return seclo * NSEC_PER_SEC + nsec;

}

​

static u64 jcore_clocksource_read(struct clocksource *cs)

{

    return jcore_sched_clock_read();

}

​

static int jcore_pit_disable(struct jcore_pit *pit)

{

    writel(0, pit->base + REG_PITEN);

    return 0;

}

​

static int jcore_pit_set(unsigned long delta, struct jcore_pit *pit)

{

    jcore_pit_disable(pit);

    writel(delta, pit->base + REG_THROT);

    writel(pit->enable_val, pit->base + REG_PITEN);

    return 0;

}

​

static int jcore_pit_set_state_shutdown(struct clock_event_device *ced)

{

    struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);

​

    return jcore_pit_disable(pit);

}

​

static int jcore_pit_set_state_oneshot(struct clock_event_device *ced)

{

    struct jcore_pit *pit = container_of(ced, struct jcore_pit, ced);

​

    return jcore_pit_disable(pit);

}

​