117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
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/*
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* arch/arm/mach-sti/platsmp.c
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*
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* Copyright (C) 2013 STMicroelectronics (R&D) Limited.
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* http://www.st.com
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*
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* Cloned from linux/arch/arm/mach-vexpress/platsmp.c
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*
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* Copyright (C) 2002 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/errno.h>
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#include <linux/delay.h>
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#include <linux/smp.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <asm/cacheflush.h>
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#include <asm/smp_plat.h>
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#include <asm/smp_scu.h>
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#include "smp.h"
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static void write_pen_release(int val)
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{
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pen_release = val;
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smp_wmb();
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sync_cache_w(&pen_release);
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}
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static DEFINE_SPINLOCK(boot_lock);
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static void sti_secondary_init(unsigned int cpu)
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{
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trace_hardirqs_off();
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/*
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* let the primary processor know we're out of the
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* pen, then head off into the C entry point
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*/
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write_pen_release(-1);
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/*
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* Synchronise with the boot thread.
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*/
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spin_lock(&boot_lock);
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spin_unlock(&boot_lock);
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}
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static int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
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{
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unsigned long timeout;
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/*
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* set synchronisation state between this boot processor
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* and the secondary one
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*/
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spin_lock(&boot_lock);
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/*
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* The secondary processor is waiting to be released from
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* the holding pen - release it, then wait for it to flag
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* that it has been released by resetting pen_release.
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*
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* Note that "pen_release" is the hardware CPU ID, whereas
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* "cpu" is Linux's internal ID.
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*/
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write_pen_release(cpu_logical_map(cpu));
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/*
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* Send the secondary CPU a soft interrupt, thereby causing
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* it to jump to the secondary entrypoint.
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*/
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arch_send_wakeup_ipi_mask(cpumask_of(cpu));
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timeout = jiffies + (1 * HZ);
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while (time_before(jiffies, timeout)) {
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smp_rmb();
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if (pen_release == -1)
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break;
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udelay(10);
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}
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/*
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* now the secondary core is starting up let it run its
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* calibrations, then wait for it to finish
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*/
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spin_unlock(&boot_lock);
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return pen_release != -1 ? -ENOSYS : 0;
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}
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static void __init sti_smp_prepare_cpus(unsigned int max_cpus)
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{
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void __iomem *scu_base = NULL;
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struct device_node *np = of_find_compatible_node(
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NULL, NULL, "arm,cortex-a9-scu");
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if (np) {
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scu_base = of_iomap(np, 0);
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scu_enable(scu_base);
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of_node_put(np);
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}
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}
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struct smp_operations __initdata sti_smp_ops = {
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.smp_prepare_cpus = sti_smp_prepare_cpus,
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.smp_secondary_init = sti_secondary_init,
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.smp_boot_secondary = sti_boot_secondary,
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};
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