![Magnus Damm](/assets/img/avatar_default.png)
Add cache flushing code to the SH-Mobile specific CPU hotplug implementation. While at it, add a cpu mask to make sure the cache flushing code is finished in platform_cpu_die() before letting the SoC-specific code in shmobile_platform_cpu_kill() proceed with turning off power. Without this code CPU hotplug offline fails when cache is enabled on Cortex-A9 based SoCs. Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/*
|
|
* SMP support for R-Mobile / SH-Mobile
|
|
*
|
|
* Copyright (C) 2010 Magnus Damm
|
|
*
|
|
* Based on realview, 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 <linux/kernel.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/delay.h>
|
|
#include <mach/common.h>
|
|
#include <asm/cacheflush.h>
|
|
|
|
static cpumask_t dead_cpus;
|
|
|
|
int platform_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 (cpumask_test_cpu(cpu, &dead_cpus))
|
|
return shmobile_platform_cpu_kill(cpu);
|
|
|
|
mdelay(1);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void platform_cpu_die(unsigned int cpu)
|
|
{
|
|
/* hardware shutdown code running on the CPU that is being offlined */
|
|
flush_cache_all();
|
|
dsb();
|
|
|
|
/* notify platform_cpu_kill() that hardware shutdown is finished */
|
|
cpumask_set_cpu(cpu, &dead_cpus);
|
|
|
|
/* wait for SoC code in platform_cpu_kill() to shut off CPU core
|
|
* power. CPU bring up starts from the reset vector.
|
|
*/
|
|
while (1) {
|
|
/*
|
|
* here's the WFI
|
|
*/
|
|
asm(".word 0xe320f003\n"
|
|
:
|
|
:
|
|
: "memory", "cc");
|
|
}
|
|
}
|
|
|
|
int platform_cpu_disable(unsigned int cpu)
|
|
{
|
|
cpumask_clear_cpu(cpu, &dead_cpus);
|
|
/*
|
|
* we don't allow CPU 0 to be shutdown (it is still too special
|
|
* e.g. clock tick interrupts)
|
|
*/
|
|
return cpu == 0 ? -EPERM : 0;
|
|
}
|