arm: berlin: add CPU hotplug support (a7b3d5a7) · Commits · 戴 / test

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>

arch/arm/mach-berlin/platsmp.c

+25 −0

Original line number	Diff line number	Diff line
		@@ -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 @@ unmap_scu:
		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);

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