331 lines
8.2 KiB
C
331 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Allwinner SoCs hstimer driver.
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*
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* Copyright (C) 2013 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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#include <linux/clk.h>
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/delay.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/reset.h>
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#include <linux/slab.h>
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#include <linux/platform_device.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) (0x20 * (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_PRES(val) (((val) & 0x7) << 4)
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#define TIMER_CTL_ONESHOT BIT(7)
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#define TIMER_INTVAL_LO_REG(val) (0x20 * (val) + 0x14)
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#define TIMER_INTVAL_HI_REG(val) (0x20 * (val) + 0x18)
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#define TIMER_CNTVAL_LO_REG(val) (0x20 * (val) + 0x1c)
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#define TIMER_CNTVAL_HI_REG(val) (0x20 * (val) + 0x20)
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#define TIMER_SYNC_TICKS 3
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struct sun5i_timer {
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void __iomem *base;
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struct clk *clk;
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struct notifier_block clk_rate_cb;
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u32 ticks_per_jiffy;
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struct clocksource clksrc;
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struct clock_event_device clkevt;
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};
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#define nb_to_sun5i_timer(x) \
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container_of(x, struct sun5i_timer, clk_rate_cb)
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#define clksrc_to_sun5i_timer(x) \
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container_of(x, struct sun5i_timer, clksrc)
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#define clkevt_to_sun5i_timer(x) \
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container_of(x, struct sun5i_timer, clkevt)
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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 sun5i_clkevt_sync(struct sun5i_timer *ce)
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{
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u32 old = readl(ce->base + TIMER_CNTVAL_LO_REG(1));
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while ((old - readl(ce->base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
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cpu_relax();
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}
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static void sun5i_clkevt_time_stop(struct sun5i_timer *ce, u8 timer)
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{
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u32 val = readl(ce->base + TIMER_CTL_REG(timer));
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writel(val & ~TIMER_CTL_ENABLE, ce->base + TIMER_CTL_REG(timer));
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sun5i_clkevt_sync(ce);
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}
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static void sun5i_clkevt_time_setup(struct sun5i_timer *ce, u8 timer, u32 delay)
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{
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writel(delay, ce->base + TIMER_INTVAL_LO_REG(timer));
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}
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static void sun5i_clkevt_time_start(struct sun5i_timer *ce, u8 timer, bool periodic)
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{
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u32 val = readl(ce->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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ce->base + TIMER_CTL_REG(timer));
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}
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static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
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{
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struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
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sun5i_clkevt_time_stop(ce, 0);
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return 0;
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}
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static int sun5i_clkevt_set_oneshot(struct clock_event_device *clkevt)
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{
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struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
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sun5i_clkevt_time_stop(ce, 0);
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sun5i_clkevt_time_start(ce, 0, false);
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return 0;
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}
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static int sun5i_clkevt_set_periodic(struct clock_event_device *clkevt)
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{
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struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
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sun5i_clkevt_time_stop(ce, 0);
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sun5i_clkevt_time_setup(ce, 0, ce->ticks_per_jiffy);
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sun5i_clkevt_time_start(ce, 0, true);
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return 0;
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}
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static int sun5i_clkevt_next_event(unsigned long evt,
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struct clock_event_device *clkevt)
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{
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struct sun5i_timer *ce = clkevt_to_sun5i_timer(clkevt);
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sun5i_clkevt_time_stop(ce, 0);
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sun5i_clkevt_time_setup(ce, 0, evt - TIMER_SYNC_TICKS);
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sun5i_clkevt_time_start(ce, 0, false);
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return 0;
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}
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static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
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{
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struct sun5i_timer *ce = dev_id;
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writel(0x1, ce->base + TIMER_IRQ_ST_REG);
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ce->clkevt.event_handler(&ce->clkevt);
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return IRQ_HANDLED;
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}
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static u64 sun5i_clksrc_read(struct clocksource *clksrc)
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{
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struct sun5i_timer *cs = clksrc_to_sun5i_timer(clksrc);
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return ~readl(cs->base + TIMER_CNTVAL_LO_REG(1));
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}
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static int sun5i_rate_cb(struct notifier_block *nb,
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unsigned long event, void *data)
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{
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struct clk_notifier_data *ndata = data;
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struct sun5i_timer *cs = nb_to_sun5i_timer(nb);
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switch (event) {
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case PRE_RATE_CHANGE:
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clocksource_unregister(&cs->clksrc);
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break;
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case POST_RATE_CHANGE:
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clocksource_register_hz(&cs->clksrc, ndata->new_rate);
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clockevents_update_freq(&cs->clkevt, ndata->new_rate);
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cs->ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
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break;
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default:
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break;
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}
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return NOTIFY_DONE;
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}
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static int sun5i_setup_clocksource(struct platform_device *pdev,
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unsigned long rate)
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{
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struct sun5i_timer *cs = platform_get_drvdata(pdev);
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void __iomem *base = cs->base;
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int ret;
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writel(~0, base + TIMER_INTVAL_LO_REG(1));
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writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
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base + TIMER_CTL_REG(1));
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cs->clksrc.name = pdev->dev.of_node->name;
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cs->clksrc.rating = 340;
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cs->clksrc.read = sun5i_clksrc_read;
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cs->clksrc.mask = CLOCKSOURCE_MASK(32);
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cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
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ret = clocksource_register_hz(&cs->clksrc, rate);
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if (ret) {
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dev_err(&pdev->dev, "Couldn't register clock source.\n");
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return ret;
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}
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return 0;
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}
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static int sun5i_setup_clockevent(struct platform_device *pdev,
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unsigned long rate, int irq)
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{
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struct device *dev = &pdev->dev;
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struct sun5i_timer *ce = platform_get_drvdata(pdev);
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void __iomem *base = ce->base;
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int ret;
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u32 val;
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ce->clkevt.name = dev->of_node->name;
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ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
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ce->clkevt.set_next_event = sun5i_clkevt_next_event;
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ce->clkevt.set_state_shutdown = sun5i_clkevt_shutdown;
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ce->clkevt.set_state_periodic = sun5i_clkevt_set_periodic;
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ce->clkevt.set_state_oneshot = sun5i_clkevt_set_oneshot;
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ce->clkevt.tick_resume = sun5i_clkevt_shutdown;
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ce->clkevt.rating = 340;
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ce->clkevt.irq = irq;
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ce->clkevt.cpumask = cpu_possible_mask;
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/* Enable timer0 interrupt */
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val = readl(base + TIMER_IRQ_EN_REG);
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writel(val | TIMER_IRQ_EN(0), base + TIMER_IRQ_EN_REG);
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clockevents_config_and_register(&ce->clkevt, rate,
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TIMER_SYNC_TICKS, 0xffffffff);
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ret = devm_request_irq(dev, irq, sun5i_timer_interrupt,
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IRQF_TIMER | IRQF_IRQPOLL,
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"sun5i_timer0", ce);
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if (ret) {
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dev_err(dev, "Unable to register interrupt\n");
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return ret;
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}
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return 0;
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}
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static int sun5i_timer_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct sun5i_timer *st;
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struct reset_control *rstc;
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void __iomem *timer_base;
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struct clk *clk;
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unsigned long rate;
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int irq, ret;
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st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
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if (!st)
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return -ENOMEM;
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platform_set_drvdata(pdev, st);
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timer_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(timer_base)) {
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dev_err(dev, "Can't map registers\n");
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return PTR_ERR(timer_base);
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}
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irq = platform_get_irq(pdev, 0);
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if (irq < 0) {
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dev_err(dev, "Can't get IRQ\n");
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return irq;
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}
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clk = devm_clk_get_enabled(dev, NULL);
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if (IS_ERR(clk)) {
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dev_err(dev, "Can't get timer clock\n");
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return PTR_ERR(clk);
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}
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rate = clk_get_rate(clk);
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if (!rate) {
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dev_err(dev, "Couldn't get parent clock rate\n");
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return -EINVAL;
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}
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st->base = timer_base;
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st->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
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st->clk = clk;
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st->clk_rate_cb.notifier_call = sun5i_rate_cb;
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st->clk_rate_cb.next = NULL;
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ret = devm_clk_notifier_register(dev, clk, &st->clk_rate_cb);
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if (ret) {
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dev_err(dev, "Unable to register clock notifier.\n");
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return ret;
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}
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rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
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if (rstc)
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reset_control_deassert(rstc);
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ret = sun5i_setup_clocksource(pdev, rate);
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if (ret)
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return ret;
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ret = sun5i_setup_clockevent(pdev, rate, irq);
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if (ret)
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goto err_unreg_clocksource;
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return 0;
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err_unreg_clocksource:
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clocksource_unregister(&st->clksrc);
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return ret;
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}
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static void sun5i_timer_remove(struct platform_device *pdev)
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{
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struct sun5i_timer *st = platform_get_drvdata(pdev);
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clocksource_unregister(&st->clksrc);
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}
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static const struct of_device_id sun5i_timer_of_match[] = {
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{ .compatible = "allwinner,sun5i-a13-hstimer" },
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{ .compatible = "allwinner,sun7i-a20-hstimer" },
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{},
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};
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MODULE_DEVICE_TABLE(of, sun5i_timer_of_match);
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static struct platform_driver sun5i_timer_driver = {
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.probe = sun5i_timer_probe,
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.remove_new = sun5i_timer_remove,
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.driver = {
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.name = "sun5i-timer",
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.of_match_table = sun5i_timer_of_match,
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.suppress_bind_attrs = true,
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},
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};
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module_platform_driver(sun5i_timer_driver);
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