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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/arm/plat-versatile/platsmp.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/arm/plat-versatile/platsmp.c')
-rw-r--r--kernel/arch/arm/plat-versatile/platsmp.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/kernel/arch/arm/plat-versatile/platsmp.c b/kernel/arch/arm/plat-versatile/platsmp.c
new file mode 100644
index 000000000..b4a8d54fc
--- /dev/null
+++ b/kernel/arch/arm/plat-versatile/platsmp.c
@@ -0,0 +1,91 @@
+/*
+ * linux/arch/arm/plat-versatile/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 <asm/cacheflush.h>
+#include <asm/smp_plat.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_RAW_SPINLOCK(boot_lock);
+
+void versatile_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.
+ */
+ raw_spin_lock(&boot_lock);
+ raw_spin_unlock(&boot_lock);
+}
+
+int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ unsigned long timeout;
+
+ /*
+ * Set synchronisation state between this boot processor
+ * and the secondary one
+ */
+ raw_spin_lock(&boot_lock);
+
+ /*
+ * This is really belt and braces; we hold unintended secondary
+ * CPUs in the holding pen until we're ready for them. However,
+ * since we haven't sent them a soft interrupt, they shouldn't
+ * be there.
+ */
+ write_pen_release(cpu_logical_map(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.
+ */
+ arch_send_wakeup_ipi_mask(cpumask_of(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
+ */
+ raw_spin_unlock(&boot_lock);
+
+ return pen_release != -1 ? -ENOSYS : 0;
+}