1// SPDX-License-Identifier: GPL-2.0-only
  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
  9 */
 10#include <linux/kernel.h>
 11#include <linux/errno.h>
 12#include <linux/smp.h>
 13#include <asm/cp15.h>
 14#include <asm/smp_plat.h>
 15
 16#include "generic.h"
 17
 18static inline void cpu_enter_lowpower(void)
 19{
 20	unsigned int v;
 21
 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
 39static 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
 54static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
 55{
 56	for (;;) {
 57		wfi();
 58
 59		if (spear_pen_release == cpu) {
 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
 77/*
 78 * platform-specific code to shutdown a CPU
 79 *
 80 * Called with IRQs disabled
 81 */
 82void spear13xx_cpu_die(unsigned int cpu)
 83{
 84	int spurious = 0;
 85
 86	/*
 87	 * we're ready for shutdown now, so do it
 88	 */
 89	cpu_enter_lowpower();
 90	spear13xx_do_lowpower(cpu, &spurious);
 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}

  1/*
  2 * linux/arch/arm/mach-spear13xx/hotplug.c
  3 *
  4 * Copyright (C) 2012 ST Microelectronics Ltd.
  5 * Deepak Sikri <deepak.sikri@st.com>
  6 *
  7 * based upon linux/arch/arm/mach-realview/hotplug.c
  8 *
  9 * This program is free software; you can redistribute it and/or modify
 10 * it under the terms of the GNU General Public License version 2 as
 11 * published by the Free Software Foundation.
 12 */
 13#include <linux/kernel.h>
 14#include <linux/errno.h>
 15#include <linux/smp.h>
 16#include <asm/cp15.h>
 17#include <asm/smp_plat.h>
 18
 19static inline void cpu_enter_lowpower(void)
 20{
 21	unsigned int v;
 22
 23	asm volatile(
 24	"	mcr	p15, 0, %1, c7, c5, 0\n"
 25	"	dsb\n"
 26	/*
 27	 * Turn off coherency
 28	 */
 29	"	mrc	p15, 0, %0, c1, c0, 1\n"
 30	"	bic	%0, %0, #0x20\n"
 31	"	mcr	p15, 0, %0, c1, c0, 1\n"
 32	"	mrc	p15, 0, %0, c1, c0, 0\n"
 33	"	bic	%0, %0, %2\n"
 34	"	mcr	p15, 0, %0, c1, c0, 0\n"
 35	: "=&r" (v)
 36	: "r" (0), "Ir" (CR_C)
 37	: "cc", "memory");
 38}
 39
 40static inline void cpu_leave_lowpower(void)
 41{
 42	unsigned int v;
 43
 44	asm volatile("mrc	p15, 0, %0, c1, c0, 0\n"
 45	"	orr	%0, %0, %1\n"
 46	"	mcr	p15, 0, %0, c1, c0, 0\n"
 47	"	mrc	p15, 0, %0, c1, c0, 1\n"
 48	"	orr	%0, %0, #0x20\n"
 49	"	mcr	p15, 0, %0, c1, c0, 1\n"
 50	: "=&r" (v)
 51	: "Ir" (CR_C)
 52	: "cc");
 53}
 54
 55static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious)
 56{
 57	for (;;) {
 58		wfi();
 59
 60		if (pen_release == cpu) {
 61			/*
 62			 * OK, proper wakeup, we're done
 63			 */
 64			break;
 65		}
 66
 67		/*
 68		 * Getting here, means that we have come out of WFI without
 69		 * having been woken up - this shouldn't happen
 70		 *
 71		 * Just note it happening - when we're woken, we can report
 72		 * its occurrence.
 73		 */
 74		(*spurious)++;
 75	}
 76}
 77
 78/*
 79 * platform-specific code to shutdown a CPU
 80 *
 81 * Called with IRQs disabled
 82 */
 83void spear13xx_cpu_die(unsigned int cpu)
 84{
 85	int spurious = 0;
 86
 87	/*
 88	 * we're ready for shutdown now, so do it
 89	 */
 90	cpu_enter_lowpower();
 91	spear13xx_do_lowpower(cpu, &spurious);
 92
 93	/*
 94	 * bring this CPU back into the world of cache
 95	 * coherency, and then restore interrupts
 96	 */
 97	cpu_leave_lowpower();
 98
 99	if (spurious)
100		pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
101}