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/*
* linux/arch/arm/mach-cintegrator/platsmp.c
*
* Copyright (C) 2002 ARM Ltd.
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <asm/atomic.h>
#include <asm/delay.h>
#include <asm/mmu_context.h>
#include <asm/procinfo.h>
#include <asm/ptrace.h>
#include <asm/smp.h>
extern void integrator_secondary_startup(void);
/*
* control for which core is the next to come out of the secondary
* boot "holding pen"
*/
volatile int __cpuinitdata pen_release = -1;
unsigned long __cpuinitdata phys_pen_release = 0;
static DEFINE_SPINLOCK(boot_lock);
void __cpuinit platform_secondary_init(unsigned int cpu)
{
/*
* the primary core may have used a "cross call" soft interrupt
* to get this processor out of WFI in the BootMonitor - make
* sure that we are no longer being sent this soft interrupt
*/
smp_cross_call_done(cpumask_of_cpu(cpu));
/*
* if any interrupts are already enabled for the primary
* core (e.g. timer irq), then they will not have been enabled
* for us: do so
*/
secondary_scan_irqs();
/*
* let the primary processor know we're out of the
* pen, then head off into the C entry point
*/
pen_release = -1;
/*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
spin_unlock(&boot_lock);
}
int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
/*
* set synchronisation state between this boot processor
* and the secondary one
*/
spin_lock(&boot_lock);
/*
* The secondary processor is waiting to be released from
* the holding pen - release it, then wait for it to flag
* that it has been released by resetting pen_release.
*
* Note that "pen_release" is the hardware CPU ID, whereas
* "cpu" is Linux's internal ID.
*/
pen_release = cpu;
/*
* XXX
*
* This is a later addition to the booting protocol: the
* bootMonitor now puts secondary cores into WFI, so
* poke_milo() no longer gets the cores moving; we need
* to send a soft interrupt to wake the secondary core.
* Use smp_cross_call() for this, since there's little
* point duplicating the code here
*/
smp_cross_call(cpumask_of_cpu(cpu));
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
if (pen_release == -1)
break;
udelay(10);
}
/*
* now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
*/
spin_unlock(&boot_lock);
return pen_release != -1 ? -ENOSYS : 0;
}
static void __init poke_milo(void)
{
extern void secondary_startup(void);
/* nobody is to be released from the pen yet */
pen_release = -1;
phys_pen_release = virt_to_phys(&pen_release);
/*
* write the address of secondary startup into the system-wide
* flags register, then clear the bottom two bits, which is what
* BootMonitor is waiting for
*/
#if 1
#define CINTEGRATOR_HDR_FLAGSS_OFFSET 0x30
__raw_writel(virt_to_phys(integrator_secondary_startup),
(IO_ADDRESS(INTEGRATOR_HDR_BASE) +
CINTEGRATOR_HDR_FLAGSS_OFFSET));
#define CINTEGRATOR_HDR_FLAGSC_OFFSET 0x34
__raw_writel(3,
(IO_ADDRESS(INTEGRATOR_HDR_BASE) +
CINTEGRATOR_HDR_FLAGSC_OFFSET));
#endif
mb();
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int ncores = get_core_count();
unsigned int cpu = smp_processor_id();
int i;
/* sanity check */
if (ncores == 0) {
printk(KERN_ERR
"Integrator/CP: strange CM count of 0? Default to 1\n");
ncores = 1;
}
if (ncores > NR_CPUS) {
printk(KERN_WARNING
"Integrator/CP: no. of cores (%d) greater than configured "
"maximum of %d - clipping\n",
ncores, NR_CPUS);
ncores = NR_CPUS;
}
/*
* start with some more config for the Boot CPU, now that
* the world is a bit more alive (which was not the case
* when smp_prepare_boot_cpu() was called)
*/
smp_store_cpu_info(cpu);
/*
* are we trying to boot more cores than exist?
*/
if (max_cpus > ncores)
max_cpus = ncores;
/*
* Initialise the possible/present maps.
* cpu_possible_map describes the set of CPUs which may be present
* cpu_present_map describes the set of CPUs populated
*/
for (i = 0; i < max_cpus; i++) {
cpu_set(i, cpu_possible_map);
cpu_set(i, cpu_present_map);
}
/*
* Do we need any more CPUs? If so, then let them know where
* to start. Note that, on modern versions of MILO, the "poke"
* doesn't actually do anything until each individual core is
* sent a soft interrupt to get it out of WFI
*/
if (max_cpus > 1)
poke_milo();
}
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