root/arch/arm/mach-imx/hotplug.c

DEFINITIONS

1. cpu_enter_lowpower
2. imx_cpu_die
3. imx_cpu_kill

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2011 Freescale Semiconductor, Inc.
   4  * Copyright 2011 Linaro Ltd.
   5  */
   6 
   7 #include <linux/errno.h>
   8 #include <linux/jiffies.h>
   9 #include <asm/cp15.h>
  10 #include <asm/proc-fns.h>
  11 
  12 #include "common.h"
  13 
  14 static inline void cpu_enter_lowpower(void)
  15 {
  16         unsigned int v;
  17 
  18         asm volatile(
  19                 "mcr    p15, 0, %1, c7, c5, 0\n"
  20         "       mcr     p15, 0, %1, c7, c10, 4\n"
  21         /*
  22          * Turn off coherency
  23          */
  24         "       mrc     p15, 0, %0, c1, c0, 1\n"
  25         "       bic     %0, %0, %3\n"
  26         "       mcr     p15, 0, %0, c1, c0, 1\n"
  27         "       mrc     p15, 0, %0, c1, c0, 0\n"
  28         "       bic     %0, %0, %2\n"
  29         "       mcr     p15, 0, %0, c1, c0, 0\n"
  30           : "=&r" (v)
  31           : "r" (0), "Ir" (CR_C), "Ir" (0x40)
  32           : "cc");
  33 }
  34 
  35 /*
  36  * platform-specific code to shutdown a CPU
  37  *
  38  * Called with IRQs disabled
  39  */
  40 void imx_cpu_die(unsigned int cpu)
  41 {
  42         cpu_enter_lowpower();
  43         /*
  44          * We use the cpu jumping argument register to sync with
  45          * imx_cpu_kill() which is running on cpu0 and waiting for
  46          * the register being cleared to kill the cpu.
  47          */
  48         imx_set_cpu_arg(cpu, ~0);
  49 
  50         while (1)
  51                 cpu_do_idle();
  52 }
  53 
  54 int imx_cpu_kill(unsigned int cpu)
  55 {
  56         unsigned long timeout = jiffies + msecs_to_jiffies(50);
  57 
  58         while (imx_get_cpu_arg(cpu) == 0)
  59                 if (time_after(jiffies, timeout))
  60                         return 0;
  61         imx_enable_cpu(cpu, false);
  62         imx_set_cpu_arg(cpu, 0);
  63         return 1;
  64 }