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Commit c7c28b0f authored by Michal Simek's avatar Michal Simek
Browse files

arm: zynq: Add hotplug support 



Signed-off-by: default avatarMichal Simek <michal.simek@xilinx.com>
parent aa7eb2bb

arch/arm/mach-zynq/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -4,4 +4,7 @@ 


# Common support

obj-y				:= common.o slcr.o

CFLAGS_REMOVE_hotplug.o		=-march=armv6k

CFLAGS_hotplug.o 		=-Wa,-march=armv7-a -mcpu=cortex-a9

obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug.o

obj-$(CONFIG_SMP)		+= headsmp.o platsmp.o

arch/arm/mach-zynq/common.h

+3 −0
Original line number Diff line number Diff line
@@ -34,4 +34,7 @@ extern struct smp_operations zynq_smp_ops __initdata; 
extern void __iomem *zynq_slcr_base;

extern void __iomem *zynq_scu_base;



/* Hotplug */

extern void zynq_platform_cpu_die(unsigned int cpu);



#endif

arch/arm/mach-zynq/hotplug.c

0 → 100644
+104 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2012-2013 Xilinx

 *

 * based on linux/arch/arm/mach-realview/hotplug.c

 *

 * 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 <asm/cacheflush.h>

#include <asm/cp15.h>

#include "common.h"



static inline void zynq_cpu_enter_lowpower(void)

{

	unsigned int v;



	flush_cache_all();

	asm volatile(

	"	mcr	p15, 0, %1, c7, c5, 0\n"

	"	dsb\n"

	/*

	 * Turn off coherency

	 */

	"	mrc	p15, 0, %0, c1, c0, 1\n"

	"	bic	%0, %0, #0x40\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)

	  : "cc");

}



static inline void zynq_cpu_leave_lowpower(void)

{

	unsigned int v;



	asm volatile(

	"	mrc	p15, 0, %0, c1, c0, 0\n"

	"	orr	%0, %0, %1\n"

	"	mcr	p15, 0, %0, c1, c0, 0\n"

	"	mrc	p15, 0, %0, c1, c0, 1\n"

	"	orr	%0, %0, #0x40\n"

	"	mcr	p15, 0, %0, c1, c0, 1\n"

	  : "=&r" (v)

	  : "Ir" (CR_C)

	  : "cc");

}



static inline void zynq_platform_do_lowpower(unsigned int cpu, int *spurious)

{

	/*

	 * there is no power-control hardware on this platform, so all

	 * we can do is put the core into WFI; this is safe as the calling

	 * code will have already disabled interrupts

	 */

	for (;;) {

		dsb();

		wfi();



		/*

		 * Getting here, means that we have come out of WFI without

		 * having been woken up - this shouldn't happen

		 *

		 * Just note it happening - when we're woken, we can report

		 * its occurrence.

		 */

		(*spurious)++;

	}

}



/*

 * platform-specific code to shutdown a CPU

 *

 * Called with IRQs disabled

 */

void zynq_platform_cpu_die(unsigned int cpu)

{

	int spurious = 0;



	/*

	 * we're ready for shutdown now, so do it

	 */

	zynq_cpu_enter_lowpower();

	zynq_platform_do_lowpower(cpu, &spurious);



	/*

	 * bring this CPU back into the world of cache

	 * coherency, and then restore interrupts

	 */

	zynq_cpu_leave_lowpower();



	if (spurious)

		pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);

}

arch/arm/mach-zynq/platsmp.c

+3 −0
Original line number Diff line number Diff line
@@ -146,4 +146,7 @@ struct smp_operations zynq_smp_ops __initdata = { 
	.smp_prepare_cpus	= zynq_smp_prepare_cpus,

	.smp_secondary_init	= zynq_secondary_init,

	.smp_boot_secondary	= zynq_boot_secondary,

#ifdef CONFIG_HOTPLUG_CPU

	.cpu_die		= zynq_platform_cpu_die,

#endif

};