dw_apb_timer_of.c

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/*
 * Copyright (C) 2012 Altera Corporation
 * Copyright (c) 2011 Picochip Ltd., Jamie Iles
 *
 * Modified from mach-picoxcell/time.c
 *
 * This program is free software; you can redistribute 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 that 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, see <http://www.gnu.org/licenses/>.
 */
#include <linux/dw_apb_timer.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>

#include <asm/mach/time.h>
#include <asm/sched_clock.h>

static void timer_get_base_and_rate(struct device_node *np,
                    void __iomem **base, u32 *rate)
{
    *base = of_iomap(np, 0);

    if (!*base)
        panic("Unable to map regs for %s", np->name);

    if (of_property_read_u32(np, "clock-freq", rate) &&
        of_property_read_u32(np, "clock-frequency", rate))
        panic("No clock-frequency property for %s", np->name);
}

static void add_clockevent(struct device_node *event_timer)
{
    void __iomem *iobase;
    struct dw_apb_clock_event_device *ced;
    u32 irq, rate;

    irq = irq_of_parse_and_map(event_timer, 0);
    if (irq == NO_IRQ)
        panic("No IRQ for clock event timer");

    timer_get_base_and_rate(event_timer, &iobase, &rate);

    ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq,
                     rate);
    if (!ced)
        panic("Unable to initialise clockevent device");

    dw_apb_clockevent_register(ced);
}

static void add_clocksource(struct device_node *source_timer)
{
    void __iomem *iobase;
    struct dw_apb_clocksource *cs;
    u32 rate;

    timer_get_base_and_rate(source_timer, &iobase, &rate);

    cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate);
    if (!cs)
        panic("Unable to initialise clocksource device");

    dw_apb_clocksource_start(cs);
    dw_apb_clocksource_register(cs);
}

static void __iomem *sched_io_base;

static u32 read_sched_clock(void)
{
    return __raw_readl(sched_io_base);
}

static const struct of_device_id sptimer_ids[] __initconst = {
    { .compatible = "picochip,pc3x2-rtc" },
    { .compatible = "snps,dw-apb-timer-sp" },
    { /* Sentinel */ },
};

static void init_sched_clock(void)
{
    struct device_node *sched_timer;
    u32 rate;

    sched_timer = of_find_matching_node(NULL, sptimer_ids);
    if (!sched_timer)
        panic("No RTC for sched clock to use");

    timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
    of_node_put(sched_timer);

    setup_sched_clock(read_sched_clock, 32, rate);
}

static const struct of_device_id osctimer_ids[] __initconst = {
    { .compatible = "picochip,pc3x2-timer" },
    { .compatible = "snps,dw-apb-timer-osc" },
    {},
};

static void __init timer_init(void)
{
    struct device_node *event_timer, *source_timer;

    event_timer = of_find_matching_node(NULL, osctimer_ids);
    if (!event_timer)
        panic("No timer for clockevent");
    add_clockevent(event_timer);

    source_timer = of_find_matching_node(event_timer, osctimer_ids);
    if (!source_timer)
        panic("No timer for clocksource");
    add_clocksource(source_timer);

    of_node_put(source_timer);

    init_sched_clock();
}

struct sys_timer dw_apb_timer = {
    .init = timer_init,
};