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-rw-r--r--arch/arm/mach-ux500/platsmp.c169
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c
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+++ b/arch/arm/mach-ux500/platsmp.c
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+/*
+ * Copyright (C) 2002 ARM Ltd.
+ * Copyright (C) 2008 STMicroelctronics.
+ * Copyright (C) 2009 ST-Ericsson.
+ * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
+ *
+ * This file is based on arm realview platform
+ *
+ * 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/smp.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#include "setup.h"
+
+#include "db8500-regs.h"
+#include "id.h"
+
+/* This is called from headsmp.S to wakeup the secondary core */
+extern void u8500_secondary_startup(void);
+
+/*
+ * 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();
+ sync_cache_w(&pen_release);
+}
+
+static void __iomem *scu_base_addr(void)
+{
+ if (cpu_is_u8500_family() || cpu_is_ux540_family())
+ return __io_address(U8500_SCU_BASE);
+ else
+ ux500_unknown_soc();
+
+ return NULL;
+}
+
+static DEFINE_SPINLOCK(boot_lock);
+
+static void ux500_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 ux500_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.
+ */
+ write_pen_release(cpu_logical_map(cpu));
+
+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+ timeout = jiffies + (1 * HZ);
+ while (time_before(jiffies, timeout)) {
+ if (pen_release == -1)
+ break;
+ }
+
+ /*
+ * 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 wakeup_secondary(void)
+{
+ void __iomem *backupram;
+
+ if (cpu_is_u8500_family() || cpu_is_ux540_family())
+ backupram = __io_address(U8500_BACKUPRAM0_BASE);
+ else
+ ux500_unknown_soc();
+
+ /*
+ * write the address of secondary startup into the backup ram register
+ * at offset 0x1FF4, then write the magic number 0xA1FEED01 to the
+ * backup ram register at offset 0x1FF0, which is what boot rom code
+ * is waiting for. This would wake up the secondary core from WFE
+ */
+#define UX500_CPU1_JUMPADDR_OFFSET 0x1FF4
+ __raw_writel(virt_to_phys(u8500_secondary_startup),
+ backupram + UX500_CPU1_JUMPADDR_OFFSET);
+
+#define UX500_CPU1_WAKEMAGIC_OFFSET 0x1FF0
+ __raw_writel(0xA1FEED01,
+ backupram + UX500_CPU1_WAKEMAGIC_OFFSET);
+
+ /* make sure write buffer is drained */
+ mb();
+}
+
+/*
+ * Initialise the CPU possible map early - this describes the CPUs
+ * which may be present or become present in the system.
+ */
+static void __init ux500_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);
+}
+
+static void __init ux500_smp_prepare_cpus(unsigned int max_cpus)
+{
+
+ scu_enable(scu_base_addr());
+ wakeup_secondary();
+}
+
+struct smp_operations ux500_smp_ops __initdata = {
+ .smp_init_cpus = ux500_smp_init_cpus,
+ .smp_prepare_cpus = ux500_smp_prepare_cpus,
+ .smp_secondary_init = ux500_secondary_init,
+ .smp_boot_secondary = ux500_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+ .cpu_die = ux500_cpu_die,
+#endif
+};