319 lines
7.9 KiB
C
319 lines
7.9 KiB
C
/*
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* Marvell Armada 370/XP SoC timer handling.
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*
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* Copyright (C) 2012 Marvell
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*
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* Lior Amsalem <alior@marvell.com>
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* Gregory CLEMENT <gregory.clement@free-electrons.com>
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* Thomas Petazzoni <thomas.petazzoni@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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* Timer 0 is used as free-running clocksource, while timer 1 is
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* used as clock_event_device.
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*
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* ---
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* Clocksource driver for Armada 370 and Armada XP SoC.
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* This driver implements one compatible string for each SoC, given
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* each has its own characteristics:
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*
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* * Armada 370 has no 25 MHz fixed timer.
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*
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* * Armada XP cannot work properly without such 25 MHz fixed timer as
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* doing otherwise leads to using a clocksource whose frequency varies
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* when doing cpufreq frequency changes.
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*
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* See Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt
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*/
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/kernel.h>
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/timer.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_address.h>
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/sched_clock.h>
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#include <linux/percpu.h>
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/*
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* Timer block registers.
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*/
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#define TIMER_CTRL_OFF 0x0000
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#define TIMER0_EN BIT(0)
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#define TIMER0_RELOAD_EN BIT(1)
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#define TIMER0_25MHZ BIT(11)
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#define TIMER0_DIV(div) ((div) << 19)
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#define TIMER1_EN BIT(2)
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#define TIMER1_RELOAD_EN BIT(3)
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#define TIMER1_25MHZ BIT(12)
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#define TIMER1_DIV(div) ((div) << 22)
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#define TIMER_EVENTS_STATUS 0x0004
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#define TIMER0_CLR_MASK (~0x1)
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#define TIMER1_CLR_MASK (~0x100)
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#define TIMER0_RELOAD_OFF 0x0010
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#define TIMER0_VAL_OFF 0x0014
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#define TIMER1_RELOAD_OFF 0x0018
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#define TIMER1_VAL_OFF 0x001c
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#define LCL_TIMER_EVENTS_STATUS 0x0028
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/* Global timers are connected to the coherency fabric clock, and the
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below divider reduces their incrementing frequency. */
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#define TIMER_DIVIDER_SHIFT 5
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#define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT)
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/*
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* SoC-specific data.
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*/
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static void __iomem *timer_base, *local_base;
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static unsigned int timer_clk;
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static bool timer25Mhz = true;
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/*
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* Number of timer ticks per jiffy.
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*/
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static u32 ticks_per_jiffy;
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static struct clock_event_device __percpu *armada_370_xp_evt;
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static void timer_ctrl_clrset(u32 clr, u32 set)
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{
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writel((readl(timer_base + TIMER_CTRL_OFF) & ~clr) | set,
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timer_base + TIMER_CTRL_OFF);
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}
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static void local_timer_ctrl_clrset(u32 clr, u32 set)
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{
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writel((readl(local_base + TIMER_CTRL_OFF) & ~clr) | set,
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local_base + TIMER_CTRL_OFF);
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}
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static u64 notrace armada_370_xp_read_sched_clock(void)
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{
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return ~readl(timer_base + TIMER0_VAL_OFF);
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}
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/*
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* Clockevent handling.
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*/
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static int
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armada_370_xp_clkevt_next_event(unsigned long delta,
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struct clock_event_device *dev)
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{
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/*
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* Clear clockevent timer interrupt.
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*/
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writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
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/*
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* Setup new clockevent timer value.
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*/
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writel(delta, local_base + TIMER0_VAL_OFF);
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/*
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* Enable the timer.
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*/
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local_timer_ctrl_clrset(TIMER0_RELOAD_EN,
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TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT));
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return 0;
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}
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static void
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armada_370_xp_clkevt_mode(enum clock_event_mode mode,
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struct clock_event_device *dev)
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{
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if (mode == CLOCK_EVT_MODE_PERIODIC) {
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/*
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* Setup timer to fire at 1/HZ intervals.
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*/
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writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
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writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
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/*
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* Enable timer.
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*/
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local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN |
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TIMER0_EN |
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TIMER0_DIV(TIMER_DIVIDER_SHIFT));
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} else {
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/*
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* Disable timer.
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*/
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local_timer_ctrl_clrset(TIMER0_EN, 0);
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/*
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* ACK pending timer interrupt.
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*/
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writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
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}
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}
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static int armada_370_xp_clkevt_irq;
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static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
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{
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/*
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* ACK timer interrupt and call event handler.
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*/
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struct clock_event_device *evt = dev_id;
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writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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/*
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* Setup the local clock events for a CPU.
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*/
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static int armada_370_xp_timer_setup(struct clock_event_device *evt)
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{
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u32 clr = 0, set = 0;
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int cpu = smp_processor_id();
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if (timer25Mhz)
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set = TIMER0_25MHZ;
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else
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clr = TIMER0_25MHZ;
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local_timer_ctrl_clrset(clr, set);
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evt->name = "armada_370_xp_per_cpu_tick",
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evt->features = CLOCK_EVT_FEAT_ONESHOT |
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CLOCK_EVT_FEAT_PERIODIC;
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evt->shift = 32,
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evt->rating = 300,
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evt->set_next_event = armada_370_xp_clkevt_next_event,
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evt->set_mode = armada_370_xp_clkevt_mode,
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evt->irq = armada_370_xp_clkevt_irq;
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evt->cpumask = cpumask_of(cpu);
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clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
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enable_percpu_irq(evt->irq, 0);
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return 0;
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}
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static void armada_370_xp_timer_stop(struct clock_event_device *evt)
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{
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evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
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disable_percpu_irq(evt->irq);
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}
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static int armada_370_xp_timer_cpu_notify(struct notifier_block *self,
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unsigned long action, void *hcpu)
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{
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/*
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* Grab cpu pointer in each case to avoid spurious
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* preemptible warnings
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*/
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switch (action & ~CPU_TASKS_FROZEN) {
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case CPU_STARTING:
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armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
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break;
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case CPU_DYING:
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armada_370_xp_timer_stop(this_cpu_ptr(armada_370_xp_evt));
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block armada_370_xp_timer_cpu_nb = {
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.notifier_call = armada_370_xp_timer_cpu_notify,
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};
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static void __init armada_370_xp_timer_common_init(struct device_node *np)
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{
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u32 clr = 0, set = 0;
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int res;
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timer_base = of_iomap(np, 0);
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WARN_ON(!timer_base);
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local_base = of_iomap(np, 1);
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if (timer25Mhz)
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set = TIMER0_25MHZ;
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else
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clr = TIMER0_25MHZ;
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timer_ctrl_clrset(clr, set);
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local_timer_ctrl_clrset(clr, set);
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/*
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* We use timer 0 as clocksource, and private(local) timer 0
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* for clockevents
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*/
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armada_370_xp_clkevt_irq = irq_of_parse_and_map(np, 4);
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ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
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/*
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* Set scale and timer for sched_clock.
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*/
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sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
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/*
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* Setup free-running clocksource timer (interrupts
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* disabled).
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*/
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writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
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writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
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timer_ctrl_clrset(0, TIMER0_EN | TIMER0_RELOAD_EN |
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TIMER0_DIV(TIMER_DIVIDER_SHIFT));
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clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
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"armada_370_xp_clocksource",
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timer_clk, 300, 32, clocksource_mmio_readl_down);
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register_cpu_notifier(&armada_370_xp_timer_cpu_nb);
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armada_370_xp_evt = alloc_percpu(struct clock_event_device);
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/*
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* Setup clockevent timer (interrupt-driven).
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*/
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res = request_percpu_irq(armada_370_xp_clkevt_irq,
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armada_370_xp_timer_interrupt,
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"armada_370_xp_per_cpu_tick",
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armada_370_xp_evt);
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/* Immediately configure the timer on the boot CPU */
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if (!res)
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armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt));
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}
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static void __init armada_xp_timer_init(struct device_node *np)
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{
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struct clk *clk = of_clk_get_by_name(np, "fixed");
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/* The 25Mhz fixed clock is mandatory, and must always be available */
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BUG_ON(IS_ERR(clk));
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timer_clk = clk_get_rate(clk);
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armada_370_xp_timer_common_init(np);
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}
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CLOCKSOURCE_OF_DECLARE(armada_xp, "marvell,armada-xp-timer",
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armada_xp_timer_init);
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static void __init armada_370_timer_init(struct device_node *np)
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{
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struct clk *clk = of_clk_get(np, 0);
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BUG_ON(IS_ERR(clk));
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timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
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timer25Mhz = false;
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armada_370_xp_timer_common_init(np);
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}
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CLOCKSOURCE_OF_DECLARE(armada_370, "marvell,armada-370-timer",
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armada_370_timer_init);
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