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Commit e7b1c963 authored by Magnus Damm's avatar Magnus Damm Committed by Simon Horman
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ARM: shmobile: Add shared SCU CPU Hotplug code 



Add CPU Hotplug functions for SCU equipped mach-shmobile SoCs.

The functions shmobile_smp_scu_cpu_die() together with
shmobile_smp_scu_cpu_kill() perform basic shutdown and
allows checking of shutdown status. These are written
to work together with SMP boot code in  headsmp-scu.S.

Signed-off-by: default avatarMagnus Damm <damm@opensource.se>
Signed-off-by: default avatarSimon Horman <horms+renesas@verge.net.au>
parent 0da60225

arch/arm/mach-shmobile/include/mach/common.h

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ extern void shmobile_boot_scu(void); 
extern void shmobile_smp_scu_prepare_cpus(unsigned int max_cpus);

extern int shmobile_smp_scu_boot_secondary(unsigned int cpu,

					   struct task_struct *idle);

extern void shmobile_smp_scu_cpu_die(unsigned int cpu);

extern int shmobile_smp_scu_cpu_kill(unsigned int cpu);

struct clk;

extern int shmobile_clk_init(void);

extern void shmobile_handle_irq_intc(struct pt_regs *);

arch/arm/mach-shmobile/platsmp-scu.c

+45 −0
Original line number Diff line number Diff line
@@ -7,9 +7,11 @@ 
 * 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/init.h>

#include <linux/io.h>

#include <linux/smp.h>

#include <asm/cacheflush.h>

#include <asm/smp_plat.h>

#include <asm/smp_scu.h>

#include <mach/common.h>
@@ -29,3 +31,46 @@ int shmobile_smp_scu_boot_secondary(unsigned int cpu, struct task_struct *idle) 
	/* do nothing for now */

	return 0;

}



#ifdef CONFIG_HOTPLUG_CPU

void shmobile_smp_scu_cpu_die(unsigned int cpu)

{

	dsb();

	flush_cache_all();



	/* disable cache coherency */

	scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);



	/* Endless loop until reset */

	while (1)

		cpu_do_idle();

}



static int shmobile_smp_scu_psr_core_disabled(int cpu)

{

	unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);



	if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)

		return 1;



	return 0;

}



int shmobile_smp_scu_cpu_kill(unsigned int cpu)

{

	int k;



	/* this function is running on another CPU than the offline target,

	 * here we need wait for shutdown code in platform_cpu_die() to

	 * finish before asking SoC-specific code to power off the CPU core.

	 */

	for (k = 0; k < 1000; k++) {

		if (shmobile_smp_scu_psr_core_disabled(cpu))

			return 1;



		mdelay(1);

	}



	return 0;

}

#endif