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| // 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);
| }
|
|
