Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2f3edfd7 authored by Shawn Guo's avatar Shawn Guo
Browse files

ARM: imx: fix sync issue between imx_cpu_die and imx_cpu_kill 



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: default avatarShawn Guo <shawn.guo@linaro.org>
Cc: <stable@vger.kernel.org>
parent 287939a3

arch/arm/mach-imx/common.h

+2 −0
Original line number Diff line number Diff line
@@ -110,6 +110,8 @@ void tzic_handle_irq(struct pt_regs *); 


extern void imx_enable_cpu(int cpu, bool enable);

extern void imx_set_cpu_jump(int cpu, void *jump_addr);

extern u32 imx_get_cpu_arg(int cpu);

extern void imx_set_cpu_arg(int cpu, u32 arg);

extern void v7_cpu_resume(void);

extern u32 *pl310_get_save_ptr(void);

#ifdef CONFIG_SMP

arch/arm/mach-imx/hotplug.c

+12 −0
Original line number Diff line number Diff line
@@ -46,11 +46,23 @@ static inline void cpu_enter_lowpower(void) 
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;

}

arch/arm/mach-imx/src.c

+12 −0
Original line number Diff line number Diff line
@@ -43,6 +43,18 @@ void imx_set_cpu_jump(int cpu, void *jump_addr) 
		       src_base + SRC_GPR1 + cpu * 8);

}



u32 imx_get_cpu_arg(int cpu)

{

	cpu = cpu_logical_map(cpu);

	return readl_relaxed(src_base + SRC_GPR1 + cpu * 8 + 4);

}



void imx_set_cpu_arg(int cpu, u32 arg)

{

	cpu = cpu_logical_map(cpu);

	writel_relaxed(arg, src_base + SRC_GPR1 + cpu * 8 + 4);

}



void imx_src_prepare_restart(void)

{

	u32 val;