[mirror_ubuntu-bionic-kernel.git] / arch / arm / mach-vexpress / hotplug.c

/*
 *  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/smp_plat.h>
#include <asm/cp15.h>

#include "core.h"

static inline void cpu_enter_lowpower(void)
{
	unsigned int v;

	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");
}

static inline void 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, %2\n"
	"	mcr	p15, 0, %0, c1, c0, 1\n"
	  : "=&r" (v)
	  : "Ir" (CR_C), "Ir" (0x40)
	  : "cc");
}

static inline void 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 (;;) {
		wfi();

		if (pen_release == cpu_logical_map(cpu)) {
			/*
			 * OK, proper wakeup, we're done
			 */
			break;
		}

		/*
		 * 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 vexpress_cpu_die(unsigned int cpu)
{
	int spurious = 0;

	/*
	 * we're ready for shutdown now, so do it
	 */
	cpu_enter_lowpower();
	platform_do_lowpower(cpu, &spurious);

	/*
	 * bring this CPU back into the world of cache
	 * coherency, and then restore interrupts
	 */
	cpu_leave_lowpower();

	if (spurious)
		pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
}
Commit	Line	Data
e9882777 RK	1	/*
	2	* linux/arch/arm/mach-realview/hotplug.c
	3	*
	4	* Copyright (C) 2002 ARM Ltd.
	5	* All Rights Reserved
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/errno.h>
	13	#include <linux/smp.h>
	14
eb50439b	15	#include <asm/smp_plat.h>
15d07dc9	16	#include <asm/cp15.h>
e9882777	17
b47a1b46 BD	18	#include "core.h"
b47a1b46 BD	19
e9882777 RK	20	static inline void cpu_enter_lowpower(void)
	21	{
	22	unsigned int v;
	23
e9882777 RK	24	asm volatile(
	25	"mcr p15, 0, %1, c7, c5, 0\n"
	26	" mcr p15, 0, %1, c7, c10, 4\n"
	27	/*
	28	* Turn off coherency
	29	*/
	30	" mrc p15, 0, %0, c1, c0, 1\n"
	31	" bic %0, %0, %3\n"
	32	" mcr p15, 0, %0, c1, c0, 1\n"
	33	" mrc p15, 0, %0, c1, c0, 0\n"
	34	" bic %0, %0, %2\n"
	35	" mcr p15, 0, %0, c1, c0, 0\n"
	36	: "=&r" (v)
	37	: "r" (0), "Ir" (CR_C), "Ir" (0x40)
	38	: "cc");
	39	}
	40
	41	static inline void cpu_leave_lowpower(void)
	42	{
	43	unsigned int v;
	44
	45	asm volatile(
	46	"mrc p15, 0, %0, c1, c0, 0\n"
	47	" orr %0, %0, %1\n"
	48	" mcr p15, 0, %0, c1, c0, 0\n"
	49	" mrc p15, 0, %0, c1, c0, 1\n"
	50	" orr %0, %0, %2\n"
	51	" mcr p15, 0, %0, c1, c0, 1\n"
	52	: "=&r" (v)
	53	: "Ir" (CR_C), "Ir" (0x40)
	54	: "cc");
	55	}
	56
	57	static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
	58	{
	59	/*
	60	* there is no power-control hardware on this platform, so all
	61	* we can do is put the core into WFI; this is safe as the calling
	62	* code will have already disabled interrupts
	63	*/
	64	for (;;) {
b3377d18	65	wfi();
e9882777	66
4a139b64	67	if (pen_release == cpu_logical_map(cpu)) {
e9882777 RK	68	/*
	69	* OK, proper wakeup, we're done
	70	*/
	71	break;
	72	}
	73
	74	/*
	75	* Getting here, means that we have come out of WFI without
	76	* having been woken up - this shouldn't happen
	77	*
	78	* Just note it happening - when we're woken, we can report
	79	* its occurrence.
	80	*/
	81	(*spurious)++;
	82	}
	83	}
	84
e9882777 RK	85	/*
	86	* platform-specific code to shutdown a CPU
	87	*
	88	* Called with IRQs disabled
	89	*/
b96fc2f3	90	void vexpress_cpu_die(unsigned int cpu)
e9882777 RK	91	{
	92	int spurious = 0;
	93
	94	/*
	95	* we're ready for shutdown now, so do it
	96	*/
	97	cpu_enter_lowpower();
	98	platform_do_lowpower(cpu, &spurious);
	99
	100	/*
	101	* bring this CPU back into the world of cache
	102	* coherency, and then restore interrupts
	103	*/
	104	cpu_leave_lowpower();
	105
	106	if (spurious)
	107	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
	108	}