[mirror_ubuntu-eoan-kernel.git] / arch / arm / mach-oxnas / 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/cp15.h>
#include <asm/smp_plat.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, #0x20\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 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, #0x20\n"
	"	mcr	p15, 0, %0, c1, c0, 1\n"
	  : "=&r" (v)
	  : "Ir" (CR_C)
	  : "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 (;;) {
		/*
		 * here's the WFI
		 */
		asm(".word	0xe320f003\n"
		    :
		    :
		    : "memory", "cc");

		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 ox820_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
af76e806 NA	1	/*
	2	* Copyright (C) 2002 ARM Ltd.
	3	* All Rights Reserved
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9	#include <linux/kernel.h>
	10	#include <linux/errno.h>
	11	#include <linux/smp.h>
	12
	13	#include <asm/cp15.h>
	14	#include <asm/smp_plat.h>
	15
	16	static inline void cpu_enter_lowpower(void)
	17	{
	18	unsigned int v;
	19
	20	asm volatile(
	21	" mcr p15, 0, %1, c7, c5, 0\n"
	22	" mcr p15, 0, %1, c7, c10, 4\n"
	23	/*
	24	* Turn off coherency
	25	*/
	26	" mrc p15, 0, %0, c1, c0, 1\n"
	27	" bic %0, %0, #0x20\n"
	28	" mcr p15, 0, %0, c1, c0, 1\n"
	29	" mrc p15, 0, %0, c1, c0, 0\n"
	30	" bic %0, %0, %2\n"
	31	" mcr p15, 0, %0, c1, c0, 0\n"
	32	: "=&r" (v)
	33	: "r" (0), "Ir" (CR_C)
	34	: "cc");
	35	}
	36
	37	static inline void cpu_leave_lowpower(void)
	38	{
	39	unsigned int v;
	40
	41	asm volatile( "mrc p15, 0, %0, c1, c0, 0\n"
	42	" orr %0, %0, %1\n"
	43	" mcr p15, 0, %0, c1, c0, 0\n"
	44	" mrc p15, 0, %0, c1, c0, 1\n"
	45	" orr %0, %0, #0x20\n"
	46	" mcr p15, 0, %0, c1, c0, 1\n"
	47	: "=&r" (v)
	48	: "Ir" (CR_C)
	49	: "cc");
	50	}
	51
	52	static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
	53	{
	54	/*
	55	* there is no power-control hardware on this platform, so all
	56	* we can do is put the core into WFI; this is safe as the calling
	57	* code will have already disabled interrupts
	58	*/
	59	for (;;) {
	60	/*
	61	* here's the WFI
	62	*/
	63	asm(".word 0xe320f003\n"
	64	:
65	:
66	: "memory", "cc");
67
68	if (pen_release == cpu_logical_map(cpu)) {
69	/*
70	* OK, proper wakeup, we're done
71	*/
72	break;
73	}
74
75	/*
76	* Getting here, means that we have come out of WFI without
77	* having been woken up - this shouldn't happen
78	*
79	* Just note it happening - when we're woken, we can report
80	* its occurrence.
81	*/
82	(*spurious)++;
83	}
84	}
85
86	/*
87	* platform-specific code to shutdown a CPU
88	*
89	* Called with IRQs disabled
90	*/
91	void ox820_cpu_die(unsigned int cpu)
92	{
93	int spurious = 0;
94
95	/*
96	* we're ready for shutdown now, so do it
97	*/
98	cpu_enter_lowpower();
99	platform_do_lowpower(cpu, &spurious);
100
101	/*
102	* bring this CPU back into the world of cache
103	* coherency, and then restore interrupts
104	*/
105	cpu_leave_lowpower();
106
107	if (spurious)
108	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
109	}