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/* linux/arch/arm/mach-exynos4/platsmp.c
*
* Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* Cloned from linux/arch/arm/mach-vexpress/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 <asm/smp_plat.h>
#include <asm/smp_scu.h>
#include <mach/hardware.h>
#include <mach/regs-clock.h>
#include <mach/regs-pmu.h>
#include <plat/cpu.h>
#include "common.h"
extern void exynos4_secondary_startup(void);
static inline void __iomem *cpu_boot_reg_base(void)
{
if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
return S5P_INFORM5;
return S5P_VA_SYSRAM;
}
static inline void __iomem *cpu_boot_reg(int cpu)
{
void __iomem *boot_reg;
boot_reg = cpu_boot_reg_base();
if (soc_is_exynos4412())
boot_reg += 4*cpu;
return boot_reg;
}
/*
* 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)
{
return (void __iomem *)(S5P_VA_SCU);
}
static DEFINE_SPINLOCK(boot_lock);
static void __cpuinit exynos_secondary_init(unsigned int cpu)
{
/*
* 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);
}
static int __cpuinit exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
unsigned long timeout;
unsigned long phys_cpu = cpu_logical_map(cpu);
/*
* 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(phys_cpu);
if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN)) {
__raw_writel(S5P_CORE_LOCAL_PWR_EN,
S5P_ARM_CORE1_CONFIGURATION);
timeout = 10;
/* wait max 10 ms until cpu1 is on */
while ((__raw_readl(S5P_ARM_CORE1_STATUS)
& S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN) {
if (timeout-- == 0)
break;
mdelay(1);
}
if (timeout == 0) {
printk(KERN_ERR "cpu1 power enable failed");
spin_unlock(&boot_lock);
return -ETIMEDOUT;
}
}
/*
* 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.
*/
timeout = jiffies + (1 * HZ);
while (time_before(jiffies, timeout)) {
smp_rmb();
__raw_writel(virt_to_phys(exynos4_secondary_startup),
cpu_boot_reg(phys_cpu));
arch_send_wakeup_ipi_mask(cpumask_of(cpu));
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.
*/
static void __init exynos_smp_init_cpus(void)
{
void __iomem *scu_base = scu_base_addr();
unsigned int i, ncores;
if (soc_is_exynos5250())
ncores = 2;
else
ncores = scu_base ? scu_get_core_count(scu_base) : 1;
/* sanity check */
if (ncores > nr_cpu_ids) {
pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
ncores, nr_cpu_ids);
ncores = nr_cpu_ids;
}
for (i = 0; i < ncores; i++)
set_cpu_possible(i, true);
}
static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
{
int i;
if (!(soc_is_exynos5250() || soc_is_exynos5440()))
scu_enable(scu_base_addr());
/*
* Write the address of secondary startup into the
* system-wide flags register. The boot monitor waits
* until it receives a soft interrupt, and then the
* secondary CPU branches to this address.
*/
for (i = 1; i < max_cpus; ++i)
__raw_writel(virt_to_phys(exynos4_secondary_startup),
cpu_boot_reg(cpu_logical_map(i)));
}
struct smp_operations exynos_smp_ops __initdata = {
.smp_init_cpus = exynos_smp_init_cpus,
.smp_prepare_cpus = exynos_smp_prepare_cpus,
.smp_secondary_init = exynos_secondary_init,
.smp_boot_secondary = exynos_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = exynos_cpu_die,
#endif
};
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