From 19bdc9d061bcb71efd2b53083d96b59bbe1a1751 Mon Sep 17 00:00:00 2001 From: Magnus Damm Date: Fri, 17 Apr 2009 05:26:31 +0000 Subject: clocksource: sh_cmt clocksource support Add clocksource support to the sh_cmt driver. With this in place we can do tickless with a single CMT channel. Signed-off-by: Magnus Damm Signed-off-by: Paul Mundt --- drivers/clocksource/sh_cmt.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) (limited to 'drivers/clocksource') diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c index 02bae3994ab..c2475648961 100644 --- a/drivers/clocksource/sh_cmt.c +++ b/drivers/clocksource/sh_cmt.c @@ -47,6 +47,7 @@ struct sh_cmt_priv { unsigned long rate; spinlock_t lock; struct clock_event_device ced; + struct clocksource cs; unsigned long total_cycles; }; @@ -376,6 +377,68 @@ static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag) spin_unlock_irqrestore(&p->lock, flags); } +static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs) +{ + return container_of(cs, struct sh_cmt_priv, cs); +} + +static cycle_t sh_cmt_clocksource_read(struct clocksource *cs) +{ + struct sh_cmt_priv *p = cs_to_sh_cmt(cs); + unsigned long flags, raw; + unsigned long value; + int has_wrapped; + + spin_lock_irqsave(&p->lock, flags); + value = p->total_cycles; + raw = sh_cmt_get_counter(p, &has_wrapped); + + if (unlikely(has_wrapped)) + raw = p->match_value; + spin_unlock_irqrestore(&p->lock, flags); + + return value + raw; +} + +static int sh_cmt_clocksource_enable(struct clocksource *cs) +{ + struct sh_cmt_priv *p = cs_to_sh_cmt(cs); + int ret; + + p->total_cycles = 0; + + ret = sh_cmt_start(p, FLAG_CLOCKSOURCE); + if (ret) + return ret; + + /* TODO: calculate good shift from rate and counter bit width */ + cs->shift = 0; + cs->mult = clocksource_hz2mult(p->rate, cs->shift); + return 0; +} + +static void sh_cmt_clocksource_disable(struct clocksource *cs) +{ + sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE); +} + +static int sh_cmt_register_clocksource(struct sh_cmt_priv *p, + char *name, unsigned long rating) +{ + struct clocksource *cs = &p->cs; + + cs->name = name; + cs->rating = rating; + cs->read = sh_cmt_clocksource_read; + cs->enable = sh_cmt_clocksource_enable; + cs->disable = sh_cmt_clocksource_disable; + cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8); + cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; + pr_info("sh_cmt: %s used as clock source\n", cs->name); + clocksource_register(cs); + return 0; +} + static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced) { return container_of(ced, struct sh_cmt_priv, ced); @@ -483,6 +546,9 @@ int sh_cmt_register(struct sh_cmt_priv *p, char *name, if (clockevent_rating) sh_cmt_register_clockevent(p, name, clockevent_rating); + if (clocksource_rating) + sh_cmt_register_clocksource(p, name, clocksource_rating); + return 0; } -- cgit v1.2.3