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![Hans de Goede](/assets/img/avatar_default.png)
sun6i and newer have an arm arch timer which is a better sched_clock source then the sun4i-timer, and sched_clock does not have priorities, so do not register the sun4i-timer sched_clock at all on sun6i and newer. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Cc: ben.dooks@codethink.co.uk Cc: digetx@gmail.com Cc: laurent.pinchart+renesas@ideasonboard.com Cc: linux-arm-kernel@lists.infradead.org Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1427746633-9137-8-git-send-email-daniel.lezcano@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
208 lines
5.5 KiB
C
208 lines
5.5 KiB
C
/*
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* Allwinner A1X SoCs timer handling.
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*
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* Copyright (C) 2012 Maxime Ripard
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* Based on code from
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* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
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* Benn Huang <benn@allwinnertech.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/irqreturn.h>
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#include <linux/sched_clock.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#define TIMER_IRQ_EN_REG 0x00
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#define TIMER_IRQ_EN(val) BIT(val)
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#define TIMER_IRQ_ST_REG 0x04
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#define TIMER_CTL_REG(val) (0x10 * val + 0x10)
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#define TIMER_CTL_ENABLE BIT(0)
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#define TIMER_CTL_RELOAD BIT(1)
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#define TIMER_CTL_CLK_SRC(val) (((val) & 0x3) << 2)
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#define TIMER_CTL_CLK_SRC_OSC24M (1)
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#define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4)
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#define TIMER_CTL_ONESHOT BIT(7)
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#define TIMER_INTVAL_REG(val) (0x10 * (val) + 0x14)
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#define TIMER_CNTVAL_REG(val) (0x10 * (val) + 0x18)
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#define TIMER_SYNC_TICKS 3
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static void __iomem *timer_base;
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static u32 ticks_per_jiffy;
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/*
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* When we disable a timer, we need to wait at least for 2 cycles of
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* the timer source clock. We will use for that the clocksource timer
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* that is already setup and runs at the same frequency than the other
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* timers, and we never will be disabled.
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*/
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static void sun4i_clkevt_sync(void)
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{
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u32 old = readl(timer_base + TIMER_CNTVAL_REG(1));
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while ((old - readl(timer_base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS)
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cpu_relax();
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}
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static void sun4i_clkevt_time_stop(u8 timer)
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{
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u32 val = readl(timer_base + TIMER_CTL_REG(timer));
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writel(val & ~TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(timer));
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sun4i_clkevt_sync();
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}
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static void sun4i_clkevt_time_setup(u8 timer, unsigned long delay)
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{
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writel(delay, timer_base + TIMER_INTVAL_REG(timer));
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}
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static void sun4i_clkevt_time_start(u8 timer, bool periodic)
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{
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u32 val = readl(timer_base + TIMER_CTL_REG(timer));
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if (periodic)
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val &= ~TIMER_CTL_ONESHOT;
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else
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val |= TIMER_CTL_ONESHOT;
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writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
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timer_base + TIMER_CTL_REG(timer));
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}
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static void sun4i_clkevt_mode(enum clock_event_mode mode,
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struct clock_event_device *clk)
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{
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switch (mode) {
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case CLOCK_EVT_MODE_PERIODIC:
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sun4i_clkevt_time_stop(0);
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sun4i_clkevt_time_setup(0, ticks_per_jiffy);
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sun4i_clkevt_time_start(0, true);
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break;
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case CLOCK_EVT_MODE_ONESHOT:
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sun4i_clkevt_time_stop(0);
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sun4i_clkevt_time_start(0, false);
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break;
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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default:
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sun4i_clkevt_time_stop(0);
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break;
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}
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}
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static int sun4i_clkevt_next_event(unsigned long evt,
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struct clock_event_device *unused)
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{
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sun4i_clkevt_time_stop(0);
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sun4i_clkevt_time_setup(0, evt - TIMER_SYNC_TICKS);
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sun4i_clkevt_time_start(0, false);
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return 0;
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}
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static struct clock_event_device sun4i_clockevent = {
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.name = "sun4i_tick",
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.rating = 350,
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.set_mode = sun4i_clkevt_mode,
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.set_next_event = sun4i_clkevt_next_event,
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};
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static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *evt = (struct clock_event_device *)dev_id;
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writel(0x1, timer_base + TIMER_IRQ_ST_REG);
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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static struct irqaction sun4i_timer_irq = {
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.name = "sun4i_timer0",
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.flags = IRQF_TIMER | IRQF_IRQPOLL,
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.handler = sun4i_timer_interrupt,
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.dev_id = &sun4i_clockevent,
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};
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static u64 notrace sun4i_timer_sched_read(void)
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{
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return ~readl(timer_base + TIMER_CNTVAL_REG(1));
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}
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static void __init sun4i_timer_init(struct device_node *node)
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{
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unsigned long rate = 0;
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struct clk *clk;
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int ret, irq;
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u32 val;
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timer_base = of_iomap(node, 0);
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if (!timer_base)
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panic("Can't map registers");
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irq = irq_of_parse_and_map(node, 0);
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if (irq <= 0)
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panic("Can't parse IRQ");
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clk = of_clk_get(node, 0);
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if (IS_ERR(clk))
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panic("Can't get timer clock");
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clk_prepare_enable(clk);
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rate = clk_get_rate(clk);
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writel(~0, timer_base + TIMER_INTVAL_REG(1));
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writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD |
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TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
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timer_base + TIMER_CTL_REG(1));
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/*
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* sched_clock_register does not have priorities, and on sun6i and
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* later there is a better sched_clock registered by arm_arch_timer.c
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*/
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if (of_machine_is_compatible("allwinner,sun4i-a10") ||
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of_machine_is_compatible("allwinner,sun5i-a13") ||
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of_machine_is_compatible("allwinner,sun5i-a10s"))
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sched_clock_register(sun4i_timer_sched_read, 32, rate);
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clocksource_mmio_init(timer_base + TIMER_CNTVAL_REG(1), node->name,
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rate, 350, 32, clocksource_mmio_readl_down);
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ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
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writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
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timer_base + TIMER_CTL_REG(0));
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/* Make sure timer is stopped before playing with interrupts */
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sun4i_clkevt_time_stop(0);
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sun4i_clockevent.cpumask = cpu_possible_mask;
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sun4i_clockevent.irq = irq;
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clockevents_config_and_register(&sun4i_clockevent, rate,
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TIMER_SYNC_TICKS, 0xffffffff);
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ret = setup_irq(irq, &sun4i_timer_irq);
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if (ret)
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pr_warn("failed to setup irq %d\n", irq);
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/* Enable timer0 interrupt */
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val = readl(timer_base + TIMER_IRQ_EN_REG);
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writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG);
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}
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CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-a10-timer",
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sun4i_timer_init);
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