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Commit 7d35b8d0 authored by Santosh Shilimkar's avatar Santosh Shilimkar Committed by Tony Lindgren
Browse files

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: default avatarRajendra Nayak <rnayak@ti.com>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent 3f9eaf09

arch/arm/mach-omap2/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o 
# SMP support ONLY available for OMAP4

obj-$(CONFIG_SMP)			+= omap-smp.o omap-headsmp.o

obj-$(CONFIG_LOCAL_TIMERS)		+= timer-mpu.o

obj-$(CONFIG_HOTPLUG_CPU)		+= omap-hotplug.o

obj-$(CONFIG_ARCH_OMAP4)		+= omap44xx-smc.o omap4-common.o



AFLAGS_omap44xx-smc.o			:=-Wa,-march=armv7-a

arch/arm/mach-omap2/include/mach/omap4-common.h

+7 −0
Original line number Diff line number Diff line
@@ -13,6 +13,13 @@ 
#ifndef OMAP_ARCH_OMAP4_COMMON_H

#define OMAP_ARCH_OMAP4_COMMON_H



/*

 * wfi used in low power code. Directly opcode is used instead

 * of instruction to avoid mulit-omap build break

 */

#define do_wfi()			\

		__asm__ __volatile__ (".word	0xe320f003" : : : "memory")



#ifdef CONFIG_CACHE_L2X0

extern void __iomem *l2cache_base;

#endif

arch/arm/mach-omap2/omap-hotplug.c

0 → 100644
+79 −0
Original line number Diff line number Diff line 
/*

 * 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;

}

arch/arm/mach-omap2/omap-smp.c

+2 −1
Original line number Diff line number Diff line
@@ -73,9 +73,10 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) 
	 * the AuxCoreBoot1 register is updated with cpu state

	 * A barrier is added to ensure that write buffer is drained

	 */

	omap_modify_auxcoreboot0(0x200, 0x0);

	omap_modify_auxcoreboot0(0x200, 0xfffffdff);

	flush_cache_all();

	smp_wmb();

	smp_cross_call(cpumask_of(cpu));



	/*

	 * Now the secondary core is starting up let it run its