linux/arch/arm/mach-omap2/omap-hotplug.c
Santosh Shilimkar 7d35b8d09f omap4: hotplug: Add basic CPU hotplug support
This patch adds cpu hotplug support for OMAP4430. Only CPU inactive
state is supported as a low power state in the basic hot-plug support

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2010-08-02 13:18:19 +03:00

80 lines
1.7 KiB
C

/*
* OMAP4 SMP cpu-hotplug support
*
* Copyright (C) 2010 Texas Instruments, Inc.
* Author:
* Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* Platform file needed for the OMAP4 SMP. This file is based on arm
* realview smp platform.
* Copyright (c) 2002 ARM Limited.
*
* 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/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <asm/cacheflush.h>
#include <mach/omap4-common.h>
static DECLARE_COMPLETION(cpu_killed);
int platform_cpu_kill(unsigned int cpu)
{
return wait_for_completion_timeout(&cpu_killed, 5000);
}
/*
* platform-specific code to shutdown a CPU
* Called with IRQs disabled
*/
void platform_cpu_die(unsigned int cpu)
{
unsigned int this_cpu = hard_smp_processor_id();
if (cpu != this_cpu) {
pr_crit("platform_cpu_die running on %u, should be %u\n",
this_cpu, cpu);
BUG();
}
pr_notice("CPU%u: shutdown\n", cpu);
complete(&cpu_killed);
flush_cache_all();
dsb();
/*
* we're ready for shutdown now, so do it
*/
if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0)
printk(KERN_CRIT "Secure clear status failed\n");
for (;;) {
/*
* Execute WFI
*/
do_wfi();
if (omap_read_auxcoreboot0() == cpu) {
/*
* OK, proper wakeup, we're done
*/
break;
}
pr_debug("CPU%u: spurious wakeup call\n", cpu);
}
}
int platform_cpu_disable(unsigned int cpu)
{
/*
* we don't allow CPU 0 to be shutdown (it is still too special
* e.g. clock tick interrupts)
*/
return cpu == 0 ? -EPERM : 0;
}