timer.c

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/*
 * Copyright (C) ST-Ericsson SA 2011
 *
 * License Terms: GNU General Public License v2
 * Author: Mattias Wallin <[email protected]> for ST-Ericsson
 */
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/clksrc-dbx500-prcmu.h>
#include <linux/of.h>
#include <linux/of_address.h>

#include <asm/smp_twd.h>

#include <plat/mtu.h>

#include <mach/setup.h>
#include <mach/hardware.h>
#include <mach/irqs.h>

#ifdef CONFIG_HAVE_ARM_TWD
static DEFINE_TWD_LOCAL_TIMER(u8500_twd_local_timer,
                  U8500_TWD_BASE, IRQ_LOCALTIMER);

static void __init ux500_twd_init(void)
{
    struct twd_local_timer *twd_local_timer;
    int err;

    /* Use this to switch local timer base if changed in new ASICs */
    twd_local_timer = &u8500_twd_local_timer;

    if (of_have_populated_dt())
        twd_local_timer_of_register();
    else {
        err = twd_local_timer_register(twd_local_timer);
        if (err)
            pr_err("twd_local_timer_register failed %d\n", err);
    }
}
#else
#define ux500_twd_init()    do { } while(0)
#endif

const static struct of_device_id prcmu_timer_of_match[] __initconst = {
    { .compatible = "stericsson,db8500-prcmu-timer-4", },
    { },
};

static void __init ux500_timer_init(void)
{
    void __iomem *mtu_timer_base;
    void __iomem *prcmu_timer_base;
    void __iomem *tmp_base;
    struct device_node *np;

    if (cpu_is_u8500_family() || cpu_is_ux540_family()) {
        mtu_timer_base = __io_address(U8500_MTU0_BASE);
        prcmu_timer_base = __io_address(U8500_PRCMU_TIMER_4_BASE);
    } else {
        ux500_unknown_soc();
    }

    /* TODO: Once MTU has been DT:ed place code above into else. */
    if (of_have_populated_dt()) {
#ifdef CONFIG_OF
        np = of_find_matching_node(NULL, prcmu_timer_of_match);
        if (!np)
#endif
            goto dt_fail;

        tmp_base = of_iomap(np, 0);
        if (!tmp_base)
            goto dt_fail;

        prcmu_timer_base = tmp_base;
    }

dt_fail:
    /* Doing it the old fashioned way. */

    /*
     * Here we register the timerblocks active in the system.
     * Localtimers (twd) is started when both cpu is up and running.
     * MTU register a clocksource, clockevent and sched_clock.
     * Since the MTU is located in the VAPE power domain
     * it will be cleared in sleep which makes it unsuitable.
     * We however need it as a timer tick (clockevent)
     * during boot to calibrate delay until twd is started.
     * RTC-RTT have problems as timer tick during boot since it is
     * depending on delay which is not yet calibrated. RTC-RTT is in the
     * always-on powerdomain and is used as clockevent instead of twd when
     * sleeping.
     * The PRCMU timer 4 register a clocksource and
     * sched_clock with higher rating then MTU since is always-on.
     *
     */

    nmdk_timer_init(mtu_timer_base);
    clksrc_dbx500_prcmu_init(prcmu_timer_base);
    ux500_twd_init();
}

static void ux500_timer_reset(void)
{
    nmdk_clkevt_reset();
    nmdk_clksrc_reset();
}

struct sys_timer ux500_timer = {
    .init       = ux500_timer_init,
    .resume     = ux500_timer_reset,
};