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/*
* arch/arm/mach-ox820/rps-time.c
*
* Copyright (C) 2009 Oxford Semiconductor Ltd
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/sched_clock.h>
#include <mach/hardware.h>
enum {
TIMER_LOAD = 0,
TIMER_CURR = 4,
TIMER_CTRL = 8,
TIMER_CLRINT = 0xC,
TIMER_BITS = 24,
TIMER_MAX_VAL = (1 << TIMER_BITS) - 1,
TIMER_PERIODIC = (1 << 6),
TIMER_ENABLE = (1 << 7),
TIMER_DIV1 = (0 << 2),
TIMER_DIV16 = (1 << 2),
TIMER_DIV256 = (2 << 2),
TIMER1_OFFSET = 0,
TIMER2_OFFSET = 0x20,
};
static u64 notrace rps_read_sched_clock(void)
{
return ~readl_relaxed(RPSA_TIMER2_VAL);
}
static void __init rps_clocksource_init(void __iomem *base, ulong ref_rate)
{
int ret;
ulong clock_rate;
/* use prescale 16 */
clock_rate = ref_rate / 16;
iowrite32(TIMER_MAX_VAL, base + TIMER_LOAD);
iowrite32(TIMER_PERIODIC | TIMER_ENABLE | TIMER_DIV16,
base + TIMER_CTRL);
ret = clocksource_mmio_init(base + TIMER_CURR, "rps_clocksource_timer",
clock_rate, 250, TIMER_BITS,
clocksource_mmio_readl_down);
if (ret)
panic("can't register clocksource\n");
sched_clock_register(rps_read_sched_clock, TIMER_BITS, clock_rate);
}
static void __init rps_timer_init(struct device_node *np)
{
struct clk *refclk;
unsigned long ref_rate;
void __iomem *base;
refclk = of_clk_get(np, 0);
if (IS_ERR(refclk) || clk_prepare_enable(refclk))
panic("rps_timer_init: failed to get refclk\n");
ref_rate = clk_get_rate(refclk);
base = of_iomap(np, 0);
if (!base)
panic("rps_timer_init: failed to map io\n");
rps_clocksource_init(base + TIMER2_OFFSET, ref_rate);
}
CLOCKSOURCE_OF_DECLARE(nas782x, "plxtech,nas782x-rps-timer", rps_timer_init);
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