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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 <linux/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 == 0)
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 __iomem *sched_io_base;
/* This is actually same as __apbt_read_clocksource(), but with
different interface */
static u32 read_sched_clock_sptimer(void)
{
return ~__raw_readl(sched_io_base + APBTMR_N_CURRENT_VALUE);
}
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);
sched_io_base = iobase;
setup_sched_clock(read_sched_clock_sptimer, 32, rate);
}
static const struct of_device_id osctimer_ids[] __initconst = {
{ .compatible = "picochip,pc3x2-timer" },
{ .compatible = "snps,dw-apb-timer-osc" },
{ .compatible = "snps,dw-apb-timer-sp" },
{ /* Sentinel */ },
};
/*
You don't have to use dw_apb_timer for scheduler clock,
this should also work fine on arm:
twd_local_timer_of_register();
arch_timer_of_register();
arch_timer_sched_clock_init();
*/
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(event_timer);
of_node_put(source_timer);
}
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