fcd75f921d
When imx_cpu_die() is being called, the cpu should never return from the call but just in WFI and wait for hardware to take it down. So let's do cpu_do_idle() repeatly in the call. Doing this help improve the relibility of hotplug operation. Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
70 lines
1.5 KiB
C
70 lines
1.5 KiB
C
/*
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* Copyright 2011 Freescale Semiconductor, Inc.
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* Copyright 2011 Linaro Ltd.
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*
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* The code contained herein is licensed under the GNU General Public
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* License. You may obtain a copy of the GNU General Public License
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* Version 2 or later at the following locations:
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*
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* http://www.opensource.org/licenses/gpl-license.html
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* http://www.gnu.org/copyleft/gpl.html
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*/
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#include <linux/errno.h>
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#include <linux/jiffies.h>
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#include <asm/cp15.h>
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#include <asm/proc-fns.h>
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#include "common.h"
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static inline void cpu_enter_lowpower(void)
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{
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unsigned int v;
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asm volatile(
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"mcr p15, 0, %1, c7, c5, 0\n"
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" mcr p15, 0, %1, c7, c10, 4\n"
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/*
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* Turn off coherency
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*/
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" mrc p15, 0, %0, c1, c0, 1\n"
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" bic %0, %0, %3\n"
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" mcr p15, 0, %0, c1, c0, 1\n"
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" mrc p15, 0, %0, c1, c0, 0\n"
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" bic %0, %0, %2\n"
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" mcr p15, 0, %0, c1, c0, 0\n"
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: "=&r" (v)
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: "r" (0), "Ir" (CR_C), "Ir" (0x40)
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: "cc");
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}
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/*
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* platform-specific code to shutdown a CPU
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*
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* Called with IRQs disabled
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*/
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void imx_cpu_die(unsigned int cpu)
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{
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cpu_enter_lowpower();
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/*
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* We use the cpu jumping argument register to sync with
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* imx_cpu_kill() which is running on cpu0 and waiting for
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* the register being cleared to kill the cpu.
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*/
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imx_set_cpu_arg(cpu, ~0);
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while (1)
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cpu_do_idle();
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}
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int imx_cpu_kill(unsigned int cpu)
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{
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unsigned long timeout = jiffies + msecs_to_jiffies(50);
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while (imx_get_cpu_arg(cpu) == 0)
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if (time_after(jiffies, timeout))
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return 0;
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imx_enable_cpu(cpu, false);
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imx_set_cpu_arg(cpu, 0);
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return 1;
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}
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