[mirror_ubuntu-jammy-kernel.git] / arch / arm / mach-spear / hotplug.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/arch/arm/mach-spear13xx/hotplug.c
 *
 * Copyright (C) 2012 ST Microelectronics Ltd.
 * Deepak Sikri <deepak.sikri@st.com>
 *
 * based upon linux/arch/arm/mach-realview/hotplug.c
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <asm/cp15.h>
#include <asm/smp_plat.h>

#include "generic.h"

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

	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, #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", "memory");
}

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 spear13xx_do_lowpower(unsigned int cpu, int *spurious)
{
	for (;;) {
		wfi();

		if (spear_pen_release == 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 spear13xx_cpu_die(unsigned int cpu)
{
	int spurious = 0;

	/*
	 * we're ready for shutdown now, so do it
	 */
	cpu_enter_lowpower();
	spear13xx_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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
e3978dc7 VK	2	/*
	3	* linux/arch/arm/mach-spear13xx/hotplug.c
	4	*
	5	* Copyright (C) 2012 ST Microelectronics Ltd.
	6	* Deepak Sikri <deepak.sikri@st.com>
	7	*
	8	* based upon linux/arch/arm/mach-realview/hotplug.c
e3978dc7 VK	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/errno.h>
	12	#include <linux/smp.h>
e3978dc7 VK	13	#include <asm/cp15.h>
	14	#include <asm/smp_plat.h>
	15
6213f70e RK	16	#include "generic.h"
6213f70e RK	17
e3978dc7 VK	18	static inline void cpu_enter_lowpower(void)
	19	{
	20	unsigned int v;
	21
e3978dc7 VK	22	asm volatile(
	23	" mcr p15, 0, %1, c7, c5, 0\n"
	24	" dsb\n"
	25	/*
	26	* Turn off coherency
	27	*/
	28	" mrc p15, 0, %0, c1, c0, 1\n"
	29	" bic %0, %0, #0x20\n"
	30	" mcr p15, 0, %0, c1, c0, 1\n"
	31	" mrc p15, 0, %0, c1, c0, 0\n"
	32	" bic %0, %0, %2\n"
	33	" mcr p15, 0, %0, c1, c0, 0\n"
	34	: "=&r" (v)
	35	: "r" (0), "Ir" (CR_C)
	36	: "cc", "memory");
	37	}
	38
	39	static inline void cpu_leave_lowpower(void)
	40	{
	41	unsigned int v;
	42
	43	asm volatile("mrc p15, 0, %0, c1, c0, 0\n"
	44	" orr %0, %0, %1\n"
	45	" mcr p15, 0, %0, c1, c0, 0\n"
	46	" mrc p15, 0, %0, c1, c0, 1\n"
	47	" orr %0, %0, #0x20\n"
	48	" mcr p15, 0, %0, c1, c0, 1\n"
	49	: "=&r" (v)
	50	: "Ir" (CR_C)
	51	: "cc");
	52	}
	53
2d8b21d9	54	static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
e3978dc7 VK	55	{
	56	for (;;) {
	57	wfi();
	58
6213f70e	59	if (spear_pen_release == cpu) {
e3978dc7 VK	60	/*
	61	* OK, proper wakeup, we're done
	62	*/
	63	break;
	64	}
	65
	66	/*
	67	* Getting here, means that we have come out of WFI without
	68	* having been woken up - this shouldn't happen
	69	*
	70	* Just note it happening - when we're woken, we can report
	71	* its occurrence.
	72	*/
	73	(*spurious)++;
	74	}
	75	}
	76
e3978dc7 VK	77	/*
	78	* platform-specific code to shutdown a CPU
	79	*
	80	* Called with IRQs disabled
	81	*/
b96fc2f3	82	void spear13xx_cpu_die(unsigned int cpu)
e3978dc7 VK	83	{
	84	int spurious = 0;
	85
	86	/*
	87	* we're ready for shutdown now, so do it
	88	*/
	89	cpu_enter_lowpower();
2d8b21d9	90	spear13xx_do_lowpower(cpu, &spurious);
e3978dc7 VK	91
	92	/*
	93	* bring this CPU back into the world of cache
	94	* coherency, and then restore interrupts
	95	*/
	96	cpu_leave_lowpower();
	97
	98	if (spurious)
	99	pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
	100	}