forked from luck/tmp_suning_uos_patched
56942fec06
The current timer-based delay loop relies on the architected timer to initiate the switch away from the polling-based implementation. This is unfortunate for platforms without the architected timers but with a suitable delay source (that is, constant frequency, always powered-up and ticking as long as the CPUs are online). This patch introduces a registration mechanism for the delay timer (which provides an unconditional read_current_timer implementation) and updates the architected timer code to use the new interface. Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
525 lines
13 KiB
C
525 lines
13 KiB
C
/*
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* linux/arch/arm/kernel/arch_timer.c
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*
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* Copyright (C) 2011 ARM Ltd.
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/smp.h>
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#include <linux/cpu.h>
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#include <linux/jiffies.h>
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#include <linux/clockchips.h>
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#include <linux/interrupt.h>
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#include <linux/of_irq.h>
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#include <linux/io.h>
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#include <asm/cputype.h>
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#include <asm/delay.h>
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#include <asm/localtimer.h>
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#include <asm/arch_timer.h>
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#include <asm/system_info.h>
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#include <asm/sched_clock.h>
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static unsigned long arch_timer_rate;
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enum ppi_nr {
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PHYS_SECURE_PPI,
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PHYS_NONSECURE_PPI,
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VIRT_PPI,
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HYP_PPI,
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MAX_TIMER_PPI
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};
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static int arch_timer_ppi[MAX_TIMER_PPI];
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static struct clock_event_device __percpu **arch_timer_evt;
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static struct delay_timer arch_delay_timer;
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static bool arch_timer_use_virtual = true;
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/*
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* Architected system timer support.
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*/
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#define ARCH_TIMER_CTRL_ENABLE (1 << 0)
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#define ARCH_TIMER_CTRL_IT_MASK (1 << 1)
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#define ARCH_TIMER_CTRL_IT_STAT (1 << 2)
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#define ARCH_TIMER_REG_CTRL 0
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#define ARCH_TIMER_REG_FREQ 1
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#define ARCH_TIMER_REG_TVAL 2
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#define ARCH_TIMER_PHYS_ACCESS 0
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#define ARCH_TIMER_VIRT_ACCESS 1
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/*
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* These register accessors are marked inline so the compiler can
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* nicely work out which register we want, and chuck away the rest of
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* the code. At least it does so with a recent GCC (4.6.3).
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*/
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static inline void arch_timer_reg_write(const int access, const int reg, u32 val)
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{
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if (access == ARCH_TIMER_PHYS_ACCESS) {
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switch (reg) {
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case ARCH_TIMER_REG_CTRL:
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asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" (val));
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break;
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case ARCH_TIMER_REG_TVAL:
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asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
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break;
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}
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}
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if (access == ARCH_TIMER_VIRT_ACCESS) {
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switch (reg) {
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case ARCH_TIMER_REG_CTRL:
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asm volatile("mcr p15, 0, %0, c14, c3, 1" : : "r" (val));
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break;
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case ARCH_TIMER_REG_TVAL:
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asm volatile("mcr p15, 0, %0, c14, c3, 0" : : "r" (val));
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break;
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}
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}
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isb();
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}
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static inline u32 arch_timer_reg_read(const int access, const int reg)
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{
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u32 val = 0;
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if (access == ARCH_TIMER_PHYS_ACCESS) {
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switch (reg) {
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case ARCH_TIMER_REG_CTRL:
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asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
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break;
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case ARCH_TIMER_REG_TVAL:
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asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
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break;
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case ARCH_TIMER_REG_FREQ:
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asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val));
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break;
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}
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}
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if (access == ARCH_TIMER_VIRT_ACCESS) {
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switch (reg) {
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case ARCH_TIMER_REG_CTRL:
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asm volatile("mrc p15, 0, %0, c14, c3, 1" : "=r" (val));
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break;
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case ARCH_TIMER_REG_TVAL:
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asm volatile("mrc p15, 0, %0, c14, c3, 0" : "=r" (val));
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break;
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}
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}
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return val;
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}
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static inline cycle_t arch_timer_counter_read(const int access)
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{
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cycle_t cval = 0;
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if (access == ARCH_TIMER_PHYS_ACCESS)
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asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (cval));
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if (access == ARCH_TIMER_VIRT_ACCESS)
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asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (cval));
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return cval;
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}
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static inline cycle_t arch_counter_get_cntpct(void)
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{
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return arch_timer_counter_read(ARCH_TIMER_PHYS_ACCESS);
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}
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static inline cycle_t arch_counter_get_cntvct(void)
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{
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return arch_timer_counter_read(ARCH_TIMER_VIRT_ACCESS);
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}
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static irqreturn_t inline timer_handler(const int access,
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struct clock_event_device *evt)
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{
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unsigned long ctrl;
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ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
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if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
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ctrl |= ARCH_TIMER_CTRL_IT_MASK;
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arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
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evt->event_handler(evt);
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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}
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static irqreturn_t arch_timer_handler_virt(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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return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
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}
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static irqreturn_t arch_timer_handler_phys(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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return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
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}
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static inline void timer_set_mode(const int access, int mode)
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{
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unsigned long ctrl;
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switch (mode) {
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case CLOCK_EVT_MODE_UNUSED:
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case CLOCK_EVT_MODE_SHUTDOWN:
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ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
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ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
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arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
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break;
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default:
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break;
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}
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}
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static void arch_timer_set_mode_virt(enum clock_event_mode mode,
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struct clock_event_device *clk)
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{
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timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode);
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}
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static void arch_timer_set_mode_phys(enum clock_event_mode mode,
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struct clock_event_device *clk)
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{
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timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode);
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}
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static inline void set_next_event(const int access, unsigned long evt)
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{
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unsigned long ctrl;
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ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL);
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ctrl |= ARCH_TIMER_CTRL_ENABLE;
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ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
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arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt);
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arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl);
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}
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static int arch_timer_set_next_event_virt(unsigned long evt,
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struct clock_event_device *unused)
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{
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set_next_event(ARCH_TIMER_VIRT_ACCESS, evt);
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return 0;
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}
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static int arch_timer_set_next_event_phys(unsigned long evt,
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struct clock_event_device *unused)
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{
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set_next_event(ARCH_TIMER_PHYS_ACCESS, evt);
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return 0;
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}
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static int __cpuinit arch_timer_setup(struct clock_event_device *clk)
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{
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clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;
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clk->name = "arch_sys_timer";
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clk->rating = 450;
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if (arch_timer_use_virtual) {
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clk->irq = arch_timer_ppi[VIRT_PPI];
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clk->set_mode = arch_timer_set_mode_virt;
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clk->set_next_event = arch_timer_set_next_event_virt;
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} else {
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clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
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clk->set_mode = arch_timer_set_mode_phys;
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clk->set_next_event = arch_timer_set_next_event_phys;
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}
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clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL);
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clockevents_config_and_register(clk, arch_timer_rate,
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0xf, 0x7fffffff);
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*__this_cpu_ptr(arch_timer_evt) = clk;
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if (arch_timer_use_virtual)
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enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0);
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else {
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enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0);
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if (arch_timer_ppi[PHYS_NONSECURE_PPI])
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enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0);
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}
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return 0;
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}
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/* Is the optional system timer available? */
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static int local_timer_is_architected(void)
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{
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return (cpu_architecture() >= CPU_ARCH_ARMv7) &&
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((read_cpuid_ext(CPUID_EXT_PFR1) >> 16) & 0xf) == 1;
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}
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static int arch_timer_available(void)
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{
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unsigned long freq;
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if (!local_timer_is_architected())
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return -ENXIO;
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if (arch_timer_rate == 0) {
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freq = arch_timer_reg_read(ARCH_TIMER_PHYS_ACCESS,
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ARCH_TIMER_REG_FREQ);
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/* Check the timer frequency. */
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if (freq == 0) {
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pr_warn("Architected timer frequency not available\n");
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return -EINVAL;
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}
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arch_timer_rate = freq;
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}
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pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n",
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arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100,
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arch_timer_use_virtual ? "virt" : "phys");
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return 0;
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}
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static u32 notrace arch_counter_get_cntpct32(void)
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{
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cycle_t cnt = arch_counter_get_cntpct();
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/*
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* The sched_clock infrastructure only knows about counters
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* with at most 32bits. Forget about the upper 24 bits for the
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* time being...
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*/
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return (u32)cnt;
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}
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static u32 notrace arch_counter_get_cntvct32(void)
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{
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cycle_t cnt = arch_counter_get_cntvct();
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/*
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* The sched_clock infrastructure only knows about counters
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* with at most 32bits. Forget about the upper 24 bits for the
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* time being...
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*/
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return (u32)cnt;
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}
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static cycle_t arch_counter_read(struct clocksource *cs)
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{
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/*
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* Always use the physical counter for the clocksource.
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* CNTHCTL.PL1PCTEN must be set to 1.
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*/
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return arch_counter_get_cntpct();
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}
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static unsigned long arch_timer_read_current_timer(void)
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{
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return arch_counter_get_cntpct();
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}
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static cycle_t arch_counter_read_cc(const struct cyclecounter *cc)
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{
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/*
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* Always use the physical counter for the clocksource.
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* CNTHCTL.PL1PCTEN must be set to 1.
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*/
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return arch_counter_get_cntpct();
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}
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static struct clocksource clocksource_counter = {
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.name = "arch_sys_counter",
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.rating = 400,
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.read = arch_counter_read,
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.mask = CLOCKSOURCE_MASK(56),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static struct cyclecounter cyclecounter = {
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.read = arch_counter_read_cc,
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.mask = CLOCKSOURCE_MASK(56),
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};
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static struct timecounter timecounter;
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struct timecounter *arch_timer_get_timecounter(void)
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{
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return &timecounter;
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}
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static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
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{
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pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n",
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clk->irq, smp_processor_id());
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if (arch_timer_use_virtual)
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disable_percpu_irq(arch_timer_ppi[VIRT_PPI]);
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else {
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disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]);
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if (arch_timer_ppi[PHYS_NONSECURE_PPI])
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disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]);
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}
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clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk);
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}
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static struct local_timer_ops arch_timer_ops __cpuinitdata = {
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.setup = arch_timer_setup,
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.stop = arch_timer_stop,
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};
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static struct clock_event_device arch_timer_global_evt;
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static int __init arch_timer_register(void)
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{
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int err;
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int ppi;
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err = arch_timer_available();
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if (err)
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goto out;
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arch_timer_evt = alloc_percpu(struct clock_event_device *);
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if (!arch_timer_evt) {
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err = -ENOMEM;
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goto out;
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}
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clocksource_register_hz(&clocksource_counter, arch_timer_rate);
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cyclecounter.mult = clocksource_counter.mult;
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cyclecounter.shift = clocksource_counter.shift;
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timecounter_init(&timecounter, &cyclecounter,
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arch_counter_get_cntpct());
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if (arch_timer_use_virtual) {
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ppi = arch_timer_ppi[VIRT_PPI];
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err = request_percpu_irq(ppi, arch_timer_handler_virt,
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"arch_timer", arch_timer_evt);
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} else {
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ppi = arch_timer_ppi[PHYS_SECURE_PPI];
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err = request_percpu_irq(ppi, arch_timer_handler_phys,
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"arch_timer", arch_timer_evt);
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if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) {
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ppi = arch_timer_ppi[PHYS_NONSECURE_PPI];
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err = request_percpu_irq(ppi, arch_timer_handler_phys,
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"arch_timer", arch_timer_evt);
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if (err)
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free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
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arch_timer_evt);
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}
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}
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if (err) {
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pr_err("arch_timer: can't register interrupt %d (%d)\n",
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ppi, err);
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goto out_free;
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}
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err = local_timer_register(&arch_timer_ops);
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if (err) {
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/*
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* We couldn't register as a local timer (could be
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* because we're on a UP platform, or because some
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* other local timer is already present...). Try as a
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* global timer instead.
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*/
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arch_timer_global_evt.cpumask = cpumask_of(0);
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err = arch_timer_setup(&arch_timer_global_evt);
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}
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if (err)
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goto out_free_irq;
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/* Use the architected timer for the delay loop. */
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arch_delay_timer.read_current_timer = &arch_timer_read_current_timer;
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arch_delay_timer.freq = arch_timer_rate;
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register_current_timer_delay(&arch_delay_timer);
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return 0;
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out_free_irq:
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if (arch_timer_use_virtual)
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free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt);
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else {
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free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI],
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arch_timer_evt);
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if (arch_timer_ppi[PHYS_NONSECURE_PPI])
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free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI],
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arch_timer_evt);
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}
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out_free:
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free_percpu(arch_timer_evt);
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out:
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return err;
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}
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static const struct of_device_id arch_timer_of_match[] __initconst = {
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{ .compatible = "arm,armv7-timer", },
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{},
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};
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int __init arch_timer_of_register(void)
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{
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struct device_node *np;
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u32 freq;
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int i;
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np = of_find_matching_node(NULL, arch_timer_of_match);
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if (!np) {
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pr_err("arch_timer: can't find DT node\n");
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return -ENODEV;
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}
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/* Try to determine the frequency from the device tree or CNTFRQ */
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if (!of_property_read_u32(np, "clock-frequency", &freq))
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arch_timer_rate = freq;
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for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
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arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
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/*
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* If no interrupt provided for virtual timer, we'll have to
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* stick to the physical timer. It'd better be accessible...
|
|
*/
|
|
if (!arch_timer_ppi[VIRT_PPI]) {
|
|
arch_timer_use_virtual = false;
|
|
|
|
if (!arch_timer_ppi[PHYS_SECURE_PPI] ||
|
|
!arch_timer_ppi[PHYS_NONSECURE_PPI]) {
|
|
pr_warn("arch_timer: No interrupt available, giving up\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
return arch_timer_register();
|
|
}
|
|
|
|
int __init arch_timer_sched_clock_init(void)
|
|
{
|
|
u32 (*cnt32)(void);
|
|
int err;
|
|
|
|
err = arch_timer_available();
|
|
if (err)
|
|
return err;
|
|
|
|
if (arch_timer_use_virtual)
|
|
cnt32 = arch_counter_get_cntvct32;
|
|
else
|
|
cnt32 = arch_counter_get_cntpct32;
|
|
|
|
setup_sched_clock(cnt32, 32, arch_timer_rate);
|
|
return 0;
|
|
}
|