From 0462b4477ea3260304bbcd97c64c0b704b4f0f85 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 19 Jan 2011 10:24:56 +0000 Subject: ARM: realview/vexpress: consolidate SMP bringup code Realview and Versatile Express share the same SMP bringup code, so consolidate the two implementations. Acked-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/plat-versatile/platsmp.c | 104 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 arch/arm/plat-versatile/platsmp.c (limited to 'arch/arm/plat-versatile/platsmp.c') diff --git a/arch/arm/plat-versatile/platsmp.c b/arch/arm/plat-versatile/platsmp.c new file mode 100644 index 000000000000..ba3d471d4bcf --- /dev/null +++ b/arch/arm/plat-versatile/platsmp.c @@ -0,0 +1,104 @@ +/* + * 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 +#include +#include +#include +#include +#include + +#include + +/* + * 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 __cpuinit 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 DEFINE_SPINLOCK(boot_lock); + +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 + */ + gic_secondary_init(0); + + /* + * 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); + + /* + * 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); + + /* + * 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. + */ + smp_cross_call(cpumask_of(cpu), 1); + + 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; +} -- cgit v1.2.1