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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/arm/mach-shmobile/platsmp-scu.c
Initial import
Diffstat (limited to 'arch/arm/mach-shmobile/platsmp-scu.c')
-rw-r--r--arch/arm/mach-shmobile/platsmp-scu.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/arch/arm/mach-shmobile/platsmp-scu.c b/arch/arm/mach-shmobile/platsmp-scu.c
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+++ b/arch/arm/mach-shmobile/platsmp-scu.c
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+/*
+ * SMP support for SoCs with SCU covered by mach-shmobile
+ *
+ * Copyright (C) 2013 Magnus Damm
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/smp.h>
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+#include "common.h"
+
+static int shmobile_smp_scu_notifier_call(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ /* For this particular CPU register SCU SMP boot vector */
+ shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
+ (unsigned long)shmobile_scu_base);
+ break;
+ };
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block shmobile_smp_scu_notifier = {
+ .notifier_call = shmobile_smp_scu_notifier_call,
+};
+
+void __init shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)
+{
+ /* install boot code shared by all CPUs */
+ shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
+ shmobile_boot_arg = MPIDR_HWID_BITMASK;
+
+ /* enable SCU and cache coherency on booting CPU */
+ scu_enable(shmobile_scu_base);
+ scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
+
+ /* Use CPU notifier for reset vector control */
+ register_cpu_notifier(&shmobile_smp_scu_notifier);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void shmobile_smp_scu_cpu_die(unsigned int cpu)
+{
+ /* For this particular CPU deregister boot vector */
+ shmobile_smp_hook(cpu, 0, 0);
+
+ dsb();
+ flush_cache_all();
+
+ /* disable cache coherency */
+ scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
+
+ /* jump to shared mach-shmobile sleep / reset code */
+ shmobile_smp_sleep();
+}
+
+static int shmobile_smp_scu_psr_core_disabled(int cpu)
+{
+ unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
+
+ if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
+ return 1;
+
+ return 0;
+}
+
+int shmobile_smp_scu_cpu_kill(unsigned int cpu)
+{
+ int k;
+
+ /* this function is running on another CPU than the offline target,
+ * here we need wait for shutdown code in platform_cpu_die() to
+ * finish before asking SoC-specific code to power off the CPU core.
+ */
+ for (k = 0; k < 1000; k++) {
+ if (shmobile_smp_scu_psr_core_disabled(cpu))
+ return 1;
+
+ mdelay(1);
+ }
+
+ return 0;
+}
+#endif