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/*
* linux/arch/arm/mach-realview/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/errno.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>
#include <asm/unified.h>
#include <mach/board-eb.h>
#include <mach/board-pb11mp.h>
#include <mach/board-pbx.h>
#include <asm/smp_scu.h>
#include "core.h"
extern void realview_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;
/*
* Write pen_release in a way that is guaranteed to be visible to all
* observers, irrespective of whether they're taking part in coherency
* or not. This is necessary for the hotplug code to work reliably.
*/
static void write_pen_release(int val)
{
pen_release = val;
smp_wmb();
__cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
}
static void __iomem *scu_base_addr(void)
{
if (machine_is_realview_eb_mp())
return __io_address(REALVIEW_EB11MP_SCU_BASE);
else if (machine_is_realview_pb11mp())
return __io_address(REALVIEW_TC11MP_SCU_BASE);
else if (machine_is_realview_pbx() &&
(core_tile_pbx11mp() || core_tile_pbxa9mp()))
return __io_address(REALVIEW_PBX_TILE_SCU_BASE);
else
return (void __iomem *)0;
}
static DEFINE_SPINLOCK(boot_lock);
void __cpuinit platform_secondary_init(unsigned int 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
*/
gic_secondary_init(0);
/*
* let the primary processor know we're out of the
* pen, then head off into the C entry point
*/
write_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.
*/
write_pen_release(cpu);
/*
* Send the secondary CPU a soft interrupt, thereby causing
* the boot monitor to read the system wide flags register,
* and branch to the address found there.
*/
smp_cross_call(cpumask_of(cpu), 1);
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
smp_rmb();
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;
}
/*
* Initialise the CPU possible map early - this describes the CPUs
* which may be present or become present in the system.
*/
void __init smp_init_cpus(void)
{
void __iomem *scu_base = scu_base_addr();
unsigned int i, ncores;
ncores = scu_base ? scu_get_core_count(scu_base) : 1;
/* sanity check */
if (ncores > NR_CPUS) {
printk(KERN_WARNING
"Realview: no. of cores (%d) greater than configured "
"maximum of %d - clipping\n",
ncores, NR_CPUS);
ncores = NR_CPUS;
}
for (i = 0; i < ncores; i++)
set_cpu_possible(i, true);
}
void __init platform_smp_prepare_cpus(unsigned int max_cpus)
{
int i;
/*
* Initialise the present map, which describes the set of CPUs
* actually populated at the present time.
*/
for (i = 0; i < max_cpus; i++)
set_cpu_present(i, true);
scu_enable(scu_base_addr());
/*
* Write the address of secondary startup into the
* system-wide flags register. The BootMonitor waits
* until it receives a soft interrupt, and then the
* secondary CPU branches to this address.
*/
__raw_writel(BSYM(virt_to_phys(realview_secondary_startup)),
__io_address(REALVIEW_SYS_FLAGSSET));
}
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