linux/arch/arm/mach-sa1100/time.c

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/*
* linux/arch/arm/mach-sa1100/time.c
*
* Copyright (C) 1998 Deborah Wallach.
* Twiddles (C) 1999 Hugo Fiennes <hugo@empeg.com>
*
* 2000/03/29 (C) Nicolas Pitre <nico@fluxnic.net>
* Rewritten: big cleanup, much simpler, better HZ accuracy.
*
*/
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/timex.h>
#include <linux/clockchips.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
#include <mach/hardware.h>
#include <mach/irqs.h>
static u32 notrace sa1100_read_sched_clock(void)
{
return readl_relaxed(OSCR);
}
#define MIN_OSCR_DELTA 2
static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* Disarm the compare/match, signal the event. */
writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER);
writel_relaxed(OSSR_M0, OSSR);
c->event_handler(c);
return IRQ_HANDLED;
}
static int
sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
{
unsigned long next, oscr;
writel_relaxed(readl_relaxed(OIER) | OIER_E0, OIER);
next = readl_relaxed(OSCR) + delta;
writel_relaxed(next, OSMR0);
oscr = readl_relaxed(OSCR);
return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
static void
sa1100_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
{
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER);
writel_relaxed(OSSR_M0, OSSR);
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
}
}
static struct clock_event_device ckevt_sa1100_osmr0 = {
.name = "osmr0",
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 200,
.set_next_event = sa1100_osmr0_set_next_event,
.set_mode = sa1100_osmr0_set_mode,
};
static struct irqaction sa1100_timer_irq = {
.name = "ost0",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = sa1100_ost0_interrupt,
.dev_id = &ckevt_sa1100_osmr0,
};
static void __init sa1100_timer_init(void)
{
writel_relaxed(0, OIER);
writel_relaxed(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);
ARM: 7205/2: sched_clock: allow sched_clock to be selected at runtime sched_clock() is yet another blocker on the road to the single image. This patch implements an idea by Russell King: http://www.spinics.net/lists/linux-omap/msg49561.html Instead of asking the platform to implement both sched_clock() itself and the rollover callback, simply register a read() function, and let the ARM code care about sched_clock() itself, the conversion to ns and the rollover. sched_clock() uses this read() function as an indirection to the platform code. If the platform doesn't provide a read(), the code falls back to the jiffy counter (just like the default sched_clock). This allow some simplifications and possibly some footprint gain when multiple platforms are compiled in. Among the drawbacks, the removal of the *_fixed_sched_clock optimization which could negatively impact some platforms (sa1100, tegra, versatile and omap). Tested on 11MPCore, OMAP4 and Tegra. Cc: Imre Kaloz <kaloz@openwrt.org> Cc: Eric Miao <eric.y.miao@gmail.com> Cc: Colin Cross <ccross@android.com> Cc: Erik Gilling <konkers@android.com> Cc: Olof Johansson <olof@lixom.net> Cc: Sascha Hauer <kernel@pengutronix.de> Cc: Alessandro Rubini <rubini@unipv.it> Cc: STEricsson <STEricsson_nomadik_linux@list.st.com> Cc: Lennert Buytenhek <kernel@wantstofly.org> Cc: Ben Dooks <ben-linux@fluff.org> Tested-by: Jamie Iles <jamie@jamieiles.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Krzysztof Halasa <khc@pm.waw.pl> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-12-15 11:19:23 +00:00
setup_sched_clock(sa1100_read_sched_clock, 32, 3686400);
clockevents_calc_mult_shift(&ckevt_sa1100_osmr0, 3686400, 4);
ckevt_sa1100_osmr0.max_delta_ns =
clockevent_delta2ns(0x7fffffff, &ckevt_sa1100_osmr0);
ckevt_sa1100_osmr0.min_delta_ns =
clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_sa1100_osmr0) + 1;
ckevt_sa1100_osmr0.cpumask = cpumask_of(0);
setup_irq(IRQ_OST0, &sa1100_timer_irq);
clocksource_mmio_init(OSCR, "oscr", CLOCK_TICK_RATE, 200, 32,
clocksource_mmio_readl_up);
clockevents_register_device(&ckevt_sa1100_osmr0);
}
#ifdef CONFIG_PM
unsigned long osmr[4], oier;
static void sa1100_timer_suspend(void)
{
osmr[0] = readl_relaxed(OSMR0);
osmr[1] = readl_relaxed(OSMR1);
osmr[2] = readl_relaxed(OSMR2);
osmr[3] = readl_relaxed(OSMR3);
oier = readl_relaxed(OIER);
}
static void sa1100_timer_resume(void)
{
writel_relaxed(0x0f, OSSR);
writel_relaxed(osmr[0], OSMR0);
writel_relaxed(osmr[1], OSMR1);
writel_relaxed(osmr[2], OSMR2);
writel_relaxed(osmr[3], OSMR3);
writel_relaxed(oier, OIER);
/*
* OSMR0 is the system timer: make sure OSCR is sufficiently behind
*/
writel_relaxed(OSMR0 - LATCH, OSCR);
}
#else
#define sa1100_timer_suspend NULL
#define sa1100_timer_resume NULL
#endif
struct sys_timer sa1100_timer = {
.init = sa1100_timer_init,
.suspend = sa1100_timer_suspend,
.resume = sa1100_timer_resume,
};