v4.19.13 snapshot.
diff --git a/arch/arm/mach-spear/platsmp.c b/arch/arm/mach-spear/platsmp.c
new file mode 100644
index 0000000..39038a0
--- /dev/null
+++ b/arch/arm/mach-spear/platsmp.c
@@ -0,0 +1,131 @@
+/*
+ * arch/arm/mach-spear13xx/platsmp.c
+ *
+ * based upon linux/arch/arm/mach-realview/platsmp.c
+ *
+ * Copyright (C) 2012 ST Microelectronics Ltd.
+ * Shiraz Hashim <shiraz.linux.kernel@gmail.com>
+ *
+ * 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/delay.h>
+#include <linux/jiffies.h>
+#include <linux/io.h>
+#include <linux/smp.h>
+#include <asm/cacheflush.h>
+#include <asm/smp_scu.h>
+#include <mach/spear.h>
+#include "generic.h"
+
+/*
+ * 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 DEFINE_SPINLOCK(boot_lock);
+
+static void __iomem *scu_base = IOMEM(VA_SCU_BASE);
+
+static void spear13xx_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 spear13xx_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);
+
+ 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.
+ */
+static void __init spear13xx_smp_init_cpus(void)
+{
+ unsigned int i, ncores = scu_get_core_count(scu_base);
+
+ 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 spear13xx_smp_prepare_cpus(unsigned int max_cpus)
+{
+
+ scu_enable(scu_base);
+
+ /*
+ * Write the address of secondary startup into the system-wide location
+ * (presently it is in SRAM). The BootMonitor waits until it receives a
+ * soft interrupt, and then the secondary CPU branches to this address.
+ */
+ __raw_writel(__pa_symbol(spear13xx_secondary_startup), SYS_LOCATION);
+}
+
+const struct smp_operations spear13xx_smp_ops __initconst = {
+ .smp_init_cpus = spear13xx_smp_init_cpus,
+ .smp_prepare_cpus = spear13xx_smp_prepare_cpus,
+ .smp_secondary_init = spear13xx_secondary_init,
+ .smp_boot_secondary = spear13xx_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+ .cpu_die = spear13xx_cpu_die,
+#endif
+};