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Diffstat (limited to 'arch/arm/kernel/psci_smp.c')
| -rw-r--r-- | arch/arm/kernel/psci_smp.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c new file mode 100644 index 000000000..cb3fcaeb2 --- /dev/null +++ b/arch/arm/kernel/psci_smp.c @@ -0,0 +1,130 @@ +/* + * 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) 2012 ARM Limited + * + * Author: Will Deacon <will.deacon@arm.com> + */ + +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/of.h> +#include <linux/delay.h> +#include <linux/psci.h> + +#include <uapi/linux/psci.h> + +#include <asm/psci.h> +#include <asm/smp_plat.h> + +/* + * psci_smp assumes that the following is true about PSCI: + * + * cpu_suspend Suspend the execution on a CPU + * @state we don't currently describe affinity levels, so just pass 0. + * @entry_point the first instruction to be executed on return + * returns 0 success, < 0 on failure + * + * cpu_off Power down a CPU + * @state we don't currently describe affinity levels, so just pass 0. + * no return on successful call + * + * cpu_on Power up a CPU + * @cpuid cpuid of target CPU, as from MPIDR + * @entry_point the first instruction to be executed on return + * returns 0 success, < 0 on failure + * + * migrate Migrate the context to a different CPU + * @cpuid cpuid of target CPU, as from MPIDR + * returns 0 success, < 0 on failure + * + */ + +extern void secondary_startup(void); + +static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + if (psci_ops.cpu_on) + return psci_ops.cpu_on(cpu_logical_map(cpu), + virt_to_idmap(&secondary_startup)); + return -ENODEV; +} + +#ifdef CONFIG_HOTPLUG_CPU +int 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; +} + +void psci_cpu_die(unsigned int cpu) +{ + u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << + PSCI_0_2_POWER_STATE_TYPE_SHIFT; + + if (psci_ops.cpu_off) + psci_ops.cpu_off(state); + + /* We should never return */ + panic("psci: cpu %d failed to shutdown\n", cpu); +} + +int psci_cpu_kill(unsigned int cpu) +{ + int err, i; + + if (!psci_ops.affinity_info) + return 1; + /* + * 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. + */ + + for (i = 0; i < 10; i++) { + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); + if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { + pr_info("CPU%d killed.\n", cpu); + return 1; + } + + msleep(10); + pr_info("Retrying again to check for CPU kill\n"); + } + + pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", + cpu, err); + /* Make platform_cpu_kill() fail. */ + return 0; +} + +#endif + +bool __init psci_smp_available(void) +{ + /* is cpu_on available at least? */ + return (psci_ops.cpu_on != NULL); +} + +const struct smp_operations psci_smp_ops __initconst = { + .smp_boot_secondary = psci_boot_secondary, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_disable = psci_cpu_disable, + .cpu_die = psci_cpu_die, + .cpu_kill = psci_cpu_kill, +#endif +}; |