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Diffstat (limited to 'arch/arm64/kernel/psci.c')
| -rw-r--r-- | arch/arm64/kernel/psci.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c new file mode 100644 index 000000000..3ebb2a56e --- /dev/null +++ b/arch/arm64/kernel/psci.c @@ -0,0 +1,129 @@ +/* + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) 2013 ARM Limited + * + * Author: Will Deacon <will.deacon@arm.com> + */ + +#define pr_fmt(fmt) "psci: " fmt + +#include <linux/init.h> +#include <linux/of.h> +#include <linux/smp.h> +#include <linux/delay.h> +#include <linux/psci.h> +#include <linux/mm.h> + +#include <uapi/linux/psci.h> + +#include <asm/compiler.h> +#include <asm/cpu_ops.h> +#include <asm/errno.h> +#include <asm/smp_plat.h> + +static int __init cpu_psci_cpu_init(unsigned int cpu) +{ + return 0; +} + +static int __init cpu_psci_cpu_prepare(unsigned int cpu) +{ + if (!psci_ops.cpu_on) { + pr_err("no cpu_on method, not booting CPU%d\n", cpu); + return -ENODEV; + } + + return 0; +} + +static int cpu_psci_cpu_boot(unsigned int cpu) +{ + int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry)); + if (err) + pr_err("failed to boot CPU%d (%d)\n", cpu, err); + + return err; +} + +#ifdef CONFIG_HOTPLUG_CPU +static int cpu_psci_cpu_disable(unsigned int cpu) +{ + /* Fail early if we don't have CPU_OFF support */ + if (!psci_ops.cpu_off) + return -EOPNOTSUPP; + + /* Trusted OS will deny CPU_OFF */ + if (psci_tos_resident_on(cpu)) + return -EPERM; + + return 0; +} + +static void cpu_psci_cpu_die(unsigned int cpu) +{ + /* + * There are no known implementations of PSCI actually using the + * power state field, pass a sensible default for now. + */ + u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << + PSCI_0_2_POWER_STATE_TYPE_SHIFT; + + psci_ops.cpu_off(state); +} + +static int cpu_psci_cpu_kill(unsigned int cpu) +{ + int err; + unsigned long start, end; + + if (!psci_ops.affinity_info) + return 0; + /* + * cpu_kill could race with cpu_die and we can + * potentially end up declaring this cpu undead + * while it is dying. So, try again a few times. + */ + + start = jiffies; + end = start + msecs_to_jiffies(100); + do { + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); + if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { + pr_info("CPU%d killed (polled %d ms)\n", cpu, + jiffies_to_msecs(jiffies - start)); + return 0; + } + + usleep_range(100, 1000); + } while (time_before(jiffies, end)); + + pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", + cpu, err); + return -ETIMEDOUT; +} +#endif + +const struct cpu_operations cpu_psci_ops = { + .name = "psci", +#ifdef CONFIG_CPU_IDLE + .cpu_init_idle = psci_cpu_init_idle, + .cpu_suspend = psci_cpu_suspend_enter, +#endif + .cpu_init = cpu_psci_cpu_init, + .cpu_prepare = cpu_psci_cpu_prepare, + .cpu_boot = cpu_psci_cpu_boot, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_disable = cpu_psci_cpu_disable, + .cpu_die = cpu_psci_cpu_die, + .cpu_kill = cpu_psci_cpu_kill, +#endif +}; + |