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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: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Magnus Damm 2013-07-31 16:07:49 +09:00 committed by Simon Horman
parent 0da60225de
commit e7b1c96384
2 changed files with 47 additions and 0 deletions
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2
arch/arm/mach-shmobile/include/mach/common.h
View File

@ -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 *);

45
arch/arm/mach-shmobile/platsmp-scu.c
View File

@ -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