94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*
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* SMP support for SoCs with SCU covered by mach-shmobile
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*
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* Copyright (C) 2013 Magnus Damm
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/cpu.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/smp.h>
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#include <asm/cacheflush.h>
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#include <asm/smp_plat.h>
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#include <asm/smp_scu.h>
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#include "common.h"
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static phys_addr_t shmobile_scu_base_phys;
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static void __iomem *shmobile_scu_base;
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static int shmobile_scu_cpu_prepare(unsigned int cpu)
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{
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/* For this particular CPU register SCU SMP boot vector */
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shmobile_smp_hook(cpu, __pa_symbol(shmobile_boot_scu),
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shmobile_scu_base_phys);
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return 0;
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}
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void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,
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unsigned int max_cpus)
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{
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/* install boot code shared by all CPUs */
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shmobile_boot_fn = __pa_symbol(shmobile_smp_boot);
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/* enable SCU and cache coherency on booting CPU */
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shmobile_scu_base_phys = scu_base_phys;
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shmobile_scu_base = ioremap(scu_base_phys, PAGE_SIZE);
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scu_enable(shmobile_scu_base);
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scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
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/* Use CPU notifier for reset vector control */
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cpuhp_setup_state_nocalls(CPUHP_ARM_SHMOBILE_SCU_PREPARE,
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"arm/shmobile-scu:prepare",
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shmobile_scu_cpu_prepare, NULL);
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}
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#ifdef CONFIG_HOTPLUG_CPU
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void shmobile_smp_scu_cpu_die(unsigned int cpu)
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{
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/* For this particular CPU deregister boot vector */
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shmobile_smp_hook(cpu, 0, 0);
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dsb();
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flush_cache_all();
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/* disable cache coherency */
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scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
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/* jump to shared mach-shmobile sleep / reset code */
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shmobile_smp_sleep();
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}
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static int shmobile_smp_scu_psr_core_disabled(int cpu)
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{
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unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
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if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
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return 1;
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return 0;
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}
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int shmobile_smp_scu_cpu_kill(unsigned int cpu)
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{
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int k;
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/* this function is running on another CPU than the offline target,
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* here we need wait for shutdown code in platform_cpu_die() to
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* finish before asking SoC-specific code to power off the CPU core.
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*/
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for (k = 0; k < 1000; k++) {
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if (shmobile_smp_scu_psr_core_disabled(cpu))
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return 1;
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mdelay(1);
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}
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return 0;
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}
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#endif
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