mirror of
https://github.com/torvalds/linux.git
synced 2024-12-11 21:52:04 +00:00
2f3edfd7e2
There is a sync issue with hotplug operation. It's possible that when imx_cpu_kill gets running on primary core, the imx_cpu_die execution on the core which is to be killed hasn't been finished yet. The problem will very likely be hit when running suspend without no_console_suspend setting on kernel cmdline. It uses cpu jumping argument register to sync imx_cpu_die and imx_cpu_kill. The register will be set in imx_cpu_die and imx_cpu_kill will wait for the register being cleared to actually kill the cpu. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Cc: <stable@vger.kernel.org>
69 lines
1.5 KiB
C
69 lines
1.5 KiB
C
/*
|
|
* Copyright 2011 Freescale Semiconductor, Inc.
|
|
* Copyright 2011 Linaro Ltd.
|
|
*
|
|
* The code contained herein is licensed under the GNU General Public
|
|
* License. You may obtain a copy of the GNU General Public License
|
|
* Version 2 or later at the following locations:
|
|
*
|
|
* http://www.opensource.org/licenses/gpl-license.html
|
|
* http://www.gnu.org/copyleft/gpl.html
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/cp15.h>
|
|
|
|
#include "common.h"
|
|
|
|
static inline void cpu_enter_lowpower(void)
|
|
{
|
|
unsigned int v;
|
|
|
|
flush_cache_all();
|
|
asm volatile(
|
|
"mcr p15, 0, %1, c7, c5, 0\n"
|
|
" mcr p15, 0, %1, c7, c10, 4\n"
|
|
/*
|
|
* Turn off coherency
|
|
*/
|
|
" mrc p15, 0, %0, c1, c0, 1\n"
|
|
" bic %0, %0, %3\n"
|
|
" mcr p15, 0, %0, c1, c0, 1\n"
|
|
" mrc p15, 0, %0, c1, c0, 0\n"
|
|
" bic %0, %0, %2\n"
|
|
" mcr p15, 0, %0, c1, c0, 0\n"
|
|
: "=&r" (v)
|
|
: "r" (0), "Ir" (CR_C), "Ir" (0x40)
|
|
: "cc");
|
|
}
|
|
|
|
/*
|
|
* platform-specific code to shutdown a CPU
|
|
*
|
|
* Called with IRQs disabled
|
|
*/
|
|
void imx_cpu_die(unsigned int cpu)
|
|
{
|
|
cpu_enter_lowpower();
|
|
/*
|
|
* We use the cpu jumping argument register to sync with
|
|
* imx_cpu_kill() which is running on cpu0 and waiting for
|
|
* the register being cleared to kill the cpu.
|
|
*/
|
|
imx_set_cpu_arg(cpu, ~0);
|
|
cpu_do_idle();
|
|
}
|
|
|
|
int imx_cpu_kill(unsigned int cpu)
|
|
{
|
|
unsigned long timeout = jiffies + msecs_to_jiffies(50);
|
|
|
|
while (imx_get_cpu_arg(cpu) == 0)
|
|
if (time_after(jiffies, timeout))
|
|
return 0;
|
|
imx_enable_cpu(cpu, false);
|
|
imx_set_cpu_arg(cpu, 0);
|
|
return 1;
|
|
}
|