linux/drivers/clocksource/dw_apb_timer_of.c

128 lines
3.3 KiB
C
Raw Normal View History

/*
* 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)
{
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
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" },
{},
};
void __init dw_apb_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();
}