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diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
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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/hardware/gic.h>
+#include <asm/smp_scu.h>
+#include <asm/unified.h>
+
+#include <mach/hardware.h>
+#include <mach/regs-clock.h>
+#include <mach/regs-pmu.h>
+
+#include <plat/cpu.h>
+
+extern unsigned int gic_bank_offset;
+extern void exynos4_secondary_startup(void);
+
+#define CPU1_BOOT_REG (samsung_rev() == EXYNOS4210_REV_1_1 ? \
+ S5P_INFORM5 : S5P_VA_SYSRAM)
+
+/*
+ * 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)
+{
+ return (void __iomem *)(S5P_VA_SCU);
+}
+
+static DEFINE_SPINLOCK(boot_lock);
+
+static void __cpuinit exynos4_gic_secondary_init(void)
+{
+ void __iomem *dist_base = S5P_VA_GIC_DIST +
+ (gic_bank_offset * smp_processor_id());
+ void __iomem *cpu_base = S5P_VA_GIC_CPU +
+ (gic_bank_offset * smp_processor_id());
+ int i;
+
+ /*
+ * Deal with the banked PPI and SGI interrupts - disable all
+ * PPI interrupts, ensure all SGI interrupts are enabled.
+ */
+ __raw_writel(0xffff0000, dist_base + GIC_DIST_ENABLE_CLEAR);
+ __raw_writel(0x0000ffff, dist_base + GIC_DIST_ENABLE_SET);
+
+ /*
+ * Set priority on PPI and SGI interrupts
+ */
+ for (i = 0; i < 32; i += 4)
+ __raw_writel(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4 / 4);
+
+ __raw_writel(0xf0, cpu_base + GIC_CPU_PRIMASK);
+ __raw_writel(1, cpu_base + GIC_CPU_CTRL);
+}
+
+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
+ */
+ exynos4_gic_secondary_init();
+
+ /*
+ * 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_logical_map(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(BSYM(virt_to_phys(exynos4_secondary_startup)),
+ CPU1_BOOT_REG);
+ gic_raise_softirq(cpumask_of(cpu), 1);
+
+ 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_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);
+
+ set_smp_cross_call(gic_raise_softirq);
+}
+
+void __init platform_smp_prepare_cpus(unsigned int max_cpus)
+{
+
+ 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.
+ */
+ __raw_writel(BSYM(virt_to_phys(exynos4_secondary_startup)),
+ CPU1_BOOT_REG);
+}