344 lines
8.8 KiB
C
344 lines
8.8 KiB
C
/*
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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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* 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/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/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) (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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};
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#define to_sun5i_timer(x) \
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container_of(x, struct sun5i_timer, clk_rate_cb)
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struct sun5i_timer_clksrc {
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struct sun5i_timer timer;
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struct clocksource clksrc;
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};
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#define to_sun5i_timer_clksrc(x) \
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container_of(x, struct sun5i_timer_clksrc, clksrc)
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struct sun5i_timer_clkevt {
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struct sun5i_timer timer;
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struct clock_event_device clkevt;
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};
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#define to_sun5i_timer_clkevt(x) \
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container_of(x, struct sun5i_timer_clkevt, 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_clkevt *ce)
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{
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u32 old = readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1));
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while ((old - readl(ce->timer.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_clkevt *ce, u8 timer)
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{
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u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
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writel(val & ~TIMER_CTL_ENABLE, ce->timer.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_clkevt *ce, u8 timer, u32 delay)
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{
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writel(delay, ce->timer.base + TIMER_INTVAL_LO_REG(timer));
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}
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static void sun5i_clkevt_time_start(struct sun5i_timer_clkevt *ce, u8 timer, bool periodic)
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{
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u32 val = readl(ce->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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ce->timer.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_clkevt *ce = to_sun5i_timer_clkevt(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_clkevt *ce = to_sun5i_timer_clkevt(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_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
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sun5i_clkevt_time_stop(ce, 0);
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sun5i_clkevt_time_setup(ce, 0, ce->timer.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_clkevt *ce = to_sun5i_timer_clkevt(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_clkevt *ce = (struct sun5i_timer_clkevt *)dev_id;
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writel(0x1, ce->timer.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 int sun5i_rate_cb_clksrc(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 *timer = to_sun5i_timer(nb);
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struct sun5i_timer_clksrc *cs = container_of(timer, struct sun5i_timer_clksrc, timer);
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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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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 __init sun5i_setup_clocksource(struct device_node *node,
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void __iomem *base,
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struct clk *clk, int irq)
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{
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struct sun5i_timer_clksrc *cs;
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unsigned long rate;
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int ret;
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cs = kzalloc(sizeof(*cs), GFP_KERNEL);
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if (!cs)
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return -ENOMEM;
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ret = clk_prepare_enable(clk);
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if (ret) {
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pr_err("Couldn't enable parent clock\n");
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goto err_free;
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}
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rate = clk_get_rate(clk);
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cs->timer.base = base;
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cs->timer.clk = clk;
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cs->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clksrc;
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cs->timer.clk_rate_cb.next = NULL;
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ret = clk_notifier_register(clk, &cs->timer.clk_rate_cb);
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if (ret) {
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pr_err("Unable to register clock notifier.\n");
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goto err_disable_clk;
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}
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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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ret = clocksource_mmio_init(base + TIMER_CNTVAL_LO_REG(1), node->name,
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rate, 340, 32, clocksource_mmio_readl_down);
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if (ret) {
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pr_err("Couldn't register clock source.\n");
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goto err_remove_notifier;
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}
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return 0;
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err_remove_notifier:
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clk_notifier_unregister(clk, &cs->timer.clk_rate_cb);
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err_disable_clk:
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clk_disable_unprepare(clk);
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err_free:
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kfree(cs);
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return ret;
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}
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static int sun5i_rate_cb_clkevt(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 *timer = to_sun5i_timer(nb);
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struct sun5i_timer_clkevt *ce = container_of(timer, struct sun5i_timer_clkevt, timer);
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if (event == POST_RATE_CHANGE) {
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clockevents_update_freq(&ce->clkevt, ndata->new_rate);
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ce->timer.ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
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}
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return NOTIFY_DONE;
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}
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static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem *base,
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struct clk *clk, int irq)
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{
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struct sun5i_timer_clkevt *ce;
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unsigned long rate;
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int ret;
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u32 val;
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ce = kzalloc(sizeof(*ce), GFP_KERNEL);
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if (!ce)
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return -ENOMEM;
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ret = clk_prepare_enable(clk);
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if (ret) {
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pr_err("Couldn't enable parent clock\n");
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goto err_free;
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}
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rate = clk_get_rate(clk);
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ce->timer.base = base;
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ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
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ce->timer.clk = clk;
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ce->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clkevt;
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ce->timer.clk_rate_cb.next = NULL;
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ret = clk_notifier_register(clk, &ce->timer.clk_rate_cb);
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if (ret) {
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pr_err("Unable to register clock notifier.\n");
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goto err_disable_clk;
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}
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ce->clkevt.name = 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 = request_irq(irq, sun5i_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
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"sun5i_timer0", ce);
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if (ret) {
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pr_err("Unable to register interrupt\n");
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goto err_remove_notifier;
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}
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return 0;
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err_remove_notifier:
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clk_notifier_unregister(clk, &ce->timer.clk_rate_cb);
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err_disable_clk:
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clk_disable_unprepare(clk);
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err_free:
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kfree(ce);
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return ret;
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}
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static void __init sun5i_timer_init(struct device_node *node)
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{
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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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int irq;
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timer_base = of_io_request_and_map(node, 0, of_node_full_name(node));
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if (IS_ERR(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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rstc = of_reset_control_get(node, NULL);
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if (!IS_ERR(rstc))
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reset_control_deassert(rstc);
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sun5i_setup_clocksource(node, timer_base, clk, irq);
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sun5i_setup_clockevent(node, timer_base, clk, irq);
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}
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CLOCKSOURCE_OF_DECLARE(sun5i_a13, "allwinner,sun5i-a13-hstimer",
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sun5i_timer_init);
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CLOCKSOURCE_OF_DECLARE(sun7i_a20, "allwinner,sun7i-a20-hstimer",
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sun5i_timer_init);
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