This patch implements the cpu_suspend cpu operations method through the PSCI CPU_SUSPEND API. The PSCI implementation translates the idle state index passed by the cpu_suspend core call into a valid PSCI state according to the PSCI states initialized at boot by the PSCI protocol backend.
Entry point is set to cpu_resume physical address, that represents the default kernel execution address following a CPU reset. Idle state index 0 is initialized to power state standby WFI so that if called by the idle driver it provides the default behaviour. Signed-off-by: Lorenzo Pieralisi <[email protected]> --- arch/arm64/include/asm/psci.h | 6 +++ arch/arm64/kernel/idle_states.c | 1 + arch/arm64/kernel/psci.c | 84 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+) diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h index e5312ea..b8ec598 100644 --- a/arch/arm64/include/asm/psci.h +++ b/arch/arm64/include/asm/psci.h @@ -14,6 +14,12 @@ #ifndef __ASM_PSCI_H #define __ASM_PSCI_H +struct idle_state; + int psci_init(void); +int __init psci_register_idle_states(struct cpumask *cpumask, + struct idle_state *idle_states, + unsigned int count); + #endif /* __ASM_PSCI_H */ diff --git a/arch/arm64/kernel/idle_states.c b/arch/arm64/kernel/idle_states.c index 0386cff..eb1e912 100644 --- a/arch/arm64/kernel/idle_states.c +++ b/arch/arm64/kernel/idle_states.c @@ -31,6 +31,7 @@ struct protocol_init { }; static const struct protocol_init protocols[] __initconst = { + {"arm,psci", psci_register_idle_states}, {} }; diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 4f97db3..fe01589 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -18,12 +18,15 @@ #include <linux/init.h> #include <linux/of.h> #include <linux/smp.h> +#include <linux/slab.h> #include <asm/compiler.h> #include <asm/cpu_ops.h> #include <asm/errno.h> +#include <asm/idle_states.h> #include <asm/psci.h> #include <asm/smp_plat.h> +#include <asm/suspend.h> #define PSCI_POWER_STATE_TYPE_STANDBY 0 #define PSCI_POWER_STATE_TYPE_POWER_DOWN 1 @@ -54,6 +57,8 @@ enum psci_function { PSCI_FN_MAX, }; +static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state); + static u32 psci_function_id[PSCI_FN_MAX]; #define PSCI_RET_SUCCESS 0 @@ -94,6 +99,17 @@ static u32 psci_power_state_pack(struct psci_power_state state) << PSCI_POWER_STATE_AFFL_SHIFT); } +static void psci_power_state_unpack(u32 power_state, + struct psci_power_state *state) +{ + state->id = (power_state >> PSCI_POWER_STATE_ID_SHIFT) + & PSCI_POWER_STATE_ID_MASK; + state->type = (power_state >> PSCI_POWER_STATE_TYPE_SHIFT) + & PSCI_POWER_STATE_TYPE_MASK; + state->affinity_level = (power_state >> PSCI_POWER_STATE_AFFL_SHIFT) + & PSCI_POWER_STATE_AFFL_MASK; +} + /* * The following two functions are invoked via the invoke_psci_fn pointer * and will not be inlined, allowing us to piggyback on the AAPCS. @@ -176,6 +192,59 @@ static const struct of_device_id psci_of_match[] __initconst = { {}, }; +int __init psci_register_idle_states(struct cpumask *cpumask, + struct idle_state *idle_states, + unsigned int count) +{ + int cpu, i; + struct psci_power_state *psci_states; + const struct cpu_operations *cpu_ops_ptr; + + if (!idle_states) + return -EINVAL; + /* + * This is belt-and-braces: make sure that if the idle + * specified protocol is psci, the cpu_ops have been + * initialized to psci operations. Anything else is + * a recipe for mayhem. + */ + for_each_cpu(cpu, cpumask) { + cpu_ops_ptr = cpu_ops[cpu]; + if (WARN_ON(!cpu_ops_ptr || strcmp(cpu_ops_ptr->name, "psci"))) + return -EOPNOTSUPP; + } + + psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); + + if (!psci_states) { + pr_warn("psci idle state allocation failed\n"); + return -ENOMEM; + } + + for_each_cpu(cpu, cpumask) { + if (per_cpu(psci_power_state, cpu)) { + pr_warn("idle states already initialized on cpu %u\n", + cpu); + continue; + } + per_cpu(psci_power_state, cpu) = psci_states; + } + + /* + * Index 0 is always considered as standby wfi + */ + psci_states[0].type = PSCI_POWER_STATE_TYPE_STANDBY; + + for (i = 1; i < count; i++) { + pr_debug("psci-power-state %#x index %u\n", + idle_states[i].state->param, i); + psci_power_state_unpack(idle_states[i].state->param, + &psci_states[i]); + } + + return 0; +} + int __init psci_init(void) { struct device_node *np; @@ -282,6 +351,18 @@ static void cpu_psci_cpu_die(unsigned int cpu) } #endif +#ifdef CONFIG_ARM64_CPU_SUSPEND +static int cpu_psci_cpu_suspend(unsigned long index) +{ + struct psci_power_state *state = __get_cpu_var(psci_power_state); + + if (!state) + return -EOPNOTSUPP; + + return psci_ops.cpu_suspend(state[index], virt_to_phys(cpu_resume)); +} +#endif + const struct cpu_operations cpu_psci_ops = { .name = "psci", .cpu_init = cpu_psci_cpu_init, @@ -291,6 +372,9 @@ const struct cpu_operations cpu_psci_ops = { .cpu_disable = cpu_psci_cpu_disable, .cpu_die = cpu_psci_cpu_die, #endif +#ifdef CONFIG_ARM64_CPU_SUSPEND + .cpu_suspend = cpu_psci_cpu_suspend, +#endif }; #endif -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
