clocksource/drivers/orion: Add delay_timer implementation
Add an implementation for the ARM delay timer, which is used for udelay(). This provides less CPU dependent and more accurate delays - the CPU loop on Marvell Dove appears to calibrate to around 6% too short. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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@ -15,6 +15,7 @@
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#include <linux/bitops.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/clk.h>
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#include <linux/clockchips.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/interrupt.h>
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#include <linux/of_address.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/of_irq.h>
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@ -36,6 +37,21 @@
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static void __iomem *timer_base;
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static void __iomem *timer_base;
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static unsigned long notrace orion_read_timer(void)
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{
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return ~readl(timer_base + TIMER0_VAL);
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}
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static struct delay_timer orion_delay_timer = {
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.read_current_timer = orion_read_timer,
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};
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static void orion_delay_timer_init(unsigned long rate)
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{
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orion_delay_timer.freq = rate;
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register_current_timer_delay(&orion_delay_timer);
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}
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/*
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/*
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* Free-running clocksource handling.
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* Free-running clocksource handling.
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*/
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*/
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@ -168,6 +184,9 @@ static int __init orion_timer_init(struct device_node *np)
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clockevents_config_and_register(&orion_clkevt, rate,
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clockevents_config_and_register(&orion_clkevt, rate,
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ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
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ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
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orion_delay_timer_init(rate);
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return 0;
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return 0;
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}
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}
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CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
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CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
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