diff options
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/Kconfig | 1 | ||||
| -rw-r--r-- | arch/mips/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/mips/kernel/pm.c | 95 |
3 files changed, 98 insertions, 0 deletions
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 5cd695f905a1..322bbe12412e 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -50,6 +50,7 @@ config MIPS select CLONE_BACKWARDS select HAVE_DEBUG_STACKOVERFLOW select HAVE_CC_STACKPROTECTOR + select CPU_PM if CPU_IDLE menu "Machine selection" diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 277dab301cea..97540a80b833 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -107,6 +107,8 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_MIPS_CM) += mips-cm.o obj-$(CONFIG_MIPS_CPC) += mips-cpc.o +obj-$(CONFIG_CPU_PM) += pm.o + # # DSP ASE supported for MIPS32 or MIPS64 Release 2 cores only. It is not # safe to unconditionnaly use the assembler -mdsp / -mdspr2 switches diff --git a/arch/mips/kernel/pm.c b/arch/mips/kernel/pm.c new file mode 100644 index 000000000000..112903f36b89 --- /dev/null +++ b/arch/mips/kernel/pm.c @@ -0,0 +1,95 @@ +/* + * Copyright (C) 2014 Imagination Technologies Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * CPU PM notifiers for saving/restoring general CPU state. + */ + +#include <linux/cpu_pm.h> +#include <linux/init.h> + +#include <asm/dsp.h> +#include <asm/fpu.h> +#include <asm/mmu_context.h> +#include <asm/watch.h> + +/** + * mips_cpu_save() - Save general CPU state. + * Ensures that general CPU context is saved, notably FPU and DSP. + */ +static int mips_cpu_save(void) +{ + /* Save FPU state */ + lose_fpu(1); + + /* Save DSP state */ + save_dsp(current); + + return 0; +} + +/** + * mips_cpu_restore() - Restore general CPU state. + * Restores important CPU context. + */ +static void mips_cpu_restore(void) +{ + unsigned int cpu = smp_processor_id(); + + /* Restore ASID */ + if (current->mm) + write_c0_entryhi(cpu_asid(cpu, current->mm)); + + /* Restore DSP state */ + restore_dsp(current); + + /* Restore UserLocal */ + if (cpu_has_userlocal) + write_c0_userlocal(current_thread_info()->tp_value); + + /* Restore watch registers */ + __restore_watch(); +} + +/** + * mips_pm_notifier() - Notifier for preserving general CPU context. + * @self: Notifier block. + * @cmd: CPU PM event. + * @v: Private data (unused). + * + * This is called when a CPU power management event occurs, and is used to + * ensure that important CPU context is preserved across a CPU power down. + */ +static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd, + void *v) +{ + int ret; + + switch (cmd) { + case CPU_PM_ENTER: + ret = mips_cpu_save(); + if (ret) + return NOTIFY_STOP; + break; + case CPU_PM_ENTER_FAILED: + case CPU_PM_EXIT: + mips_cpu_restore(); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block mips_pm_notifier_block = { + .notifier_call = mips_pm_notifier, +}; + +static int __init mips_pm_init(void) +{ + return cpu_pm_register_notifier(&mips_pm_notifier_block); +} +arch_initcall(mips_pm_init); |