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arm: berlin: add CPU hotplug support 

Add cpu hotplug support for berlin SoCs such as BG2 and BG2Q. These SoC
don't support power off cpu independently, but we also want cpu hotplug
support in these SoCs. We achieve this goal by putting the dying CPU in
WFI state after the coherency is disabled, then asserting the dying CPU
reset bit to put the CPU in reset state.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
This commit is contained in:
Jisheng Zhang 2015-09-14 14:47:45 +08:00 committed by Sebastian Hesselbarth
parent ac7fc233b2
commit a7b3d5a715
1 changed files with 25 additions and 0 deletions
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25
arch/arm/mach-berlin/platsmp.c
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@ -14,6 +14,7 @@
#include <linux/of_address.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
@ -98,8 +99,32 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
iounmap(scu_base);
}
#ifdef CONFIG_HOTPLUG_CPU
static void berlin_cpu_die(unsigned int cpu)
{
v7_exit_coherency_flush(louis);
while (1)
cpu_do_idle();
}
static int berlin_cpu_kill(unsigned int cpu)
{
u32 val;
val = readl(cpu_ctrl + CPU_RESET_NON_SC);
val &= ~BIT(cpu_logical_map(cpu));
writel(val, cpu_ctrl + CPU_RESET_NON_SC);
return 1;
}
#endif
static struct smp_operations berlin_smp_ops __initdata = {
.smp_prepare_cpus = berlin_smp_prepare_cpus,
.smp_boot_secondary = berlin_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_die = berlin_cpu_die,
.cpu_kill = berlin_cpu_kill,
#endif
};
CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);