diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index e4d3913fe330..842d7ba83101 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -48,4 +48,9 @@ config CPU_IDLE_CALXEDA help Select this to enable cpuidle on Calxeda processors. +menu "ARM64 CPU Idle Drivers" +depends on ARM64 +source "drivers/cpuidle/Kconfig.arm64" +endmenu + endif diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64 new file mode 100644 index 000000000000..b83612c67e6d --- /dev/null +++ b/drivers/cpuidle/Kconfig.arm64 @@ -0,0 +1,13 @@ +# +# ARM64 CPU Idle drivers +# + +config ARM64_CPUIDLE + bool "Generic ARM64 CPU idle Driver" + select OF_IDLE_STATES + help + Select this to enable generic cpuidle driver for ARM v8. + It provides a generic idle driver whose idle states are configured + at run-time through DT nodes. The CPUidle suspend backend is + initialized by the device tree parsing code on matching the entry + method to the respective CPU operations. diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index d41366a7838c..d3e662cde224 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -8,3 +8,7 @@ obj-$(CONFIG_OF_IDLE_STATES) += of_idle_states.o obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o + +############################################################################### +# ARM64 drivers +obj-$(CONFIG_ARM64_CPUIDLE) += cpuidle-arm64.o diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c new file mode 100644 index 000000000000..2cfde6ce3086 --- /dev/null +++ b/drivers/cpuidle/cpuidle-arm64.c @@ -0,0 +1,159 @@ +/* + * ARM64 generic CPU idle driver. + * + * Copyright (C) 2014 ARM Ltd. + * Author: Lorenzo Pieralisi + * + * 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 +#include +#include +#include +#include +#include + +#include +#include + +#include "of_idle_states.h" + +typedef int (*suspend_init_fn)(struct cpuidle_driver *, + struct device_node *[]); + +struct cpu_suspend_ops { + const char *id; + suspend_init_fn init_fn; +}; + +static const struct cpu_suspend_ops suspend_operations[] __initconst = { + {"arm,psci", psci_dt_register_idle_states}, + {} +}; + +static __init const struct cpu_suspend_ops *get_suspend_ops(const char *str) +{ + int i; + + if (!str) + return NULL; + + for (i = 0; suspend_operations[i].id; i++) + if (!strcmp(suspend_operations[i].id, str)) + return &suspend_operations[i]; + + return NULL; +} + +/* + * arm_enter_idle_state - Programs CPU to enter the specified state + * + * @dev: cpuidle device + * @drv: cpuidle driver + * @idx: state index + * + * Called from the CPUidle framework to program the device to the + * specified target state selected by the governor. + */ +static int arm_enter_idle_state(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) +{ + int ret; + + if (!idx) { + cpu_do_idle(); + return idx; + } + + cpu_pm_enter(); + /* + * Pass idle state index to cpu_suspend which in turn will call + * the CPU ops suspend protocol with idle index as a parameter. + * + * Some states would not require context to be saved and flushed + * to DRAM, so calling cpu_suspend would not be stricly necessary. + * When power domains specifications for ARM CPUs are finalized then + * this code can be optimized to prevent saving registers if not + * needed. + */ + ret = cpu_suspend(idx); + + cpu_pm_exit(); + + return ret ? -1 : idx; +} + +struct cpuidle_driver arm64_idle_driver = { + .name = "arm64_idle", + .owner = THIS_MODULE, +}; + +static struct device_node *state_nodes[CPUIDLE_STATE_MAX] __initdata; + +/* + * arm64_idle_init + * + * Registers the arm64 specific cpuidle driver with the cpuidle + * framework. It relies on core code to parse the idle states + * and initialize them using driver data structures accordingly. + */ +static int __init arm64_idle_init(void) +{ + int i, ret; + const char *entry_method; + struct device_node *idle_states_node; + const struct cpu_suspend_ops *suspend_init; + struct cpuidle_driver *drv = &arm64_idle_driver; + + idle_states_node = of_find_node_by_path("/cpus/idle-states"); + if (!idle_states_node) + return -ENOENT; + + if (of_property_read_string(idle_states_node, "entry-method", + &entry_method)) { + pr_warn(" * %s missing entry-method property\n", + idle_states_node->full_name); + of_node_put(idle_states_node); + return -EOPNOTSUPP; + } + + suspend_init = get_suspend_ops(entry_method); + if (!suspend_init) { + pr_warn("Missing suspend initializer\n"); + of_node_put(idle_states_node); + return -EOPNOTSUPP; + } + + /* + * State at index 0 is standby wfi and considered standard + * on all ARM platforms. If in some platforms simple wfi + * can't be used as "state 0", DT bindings must be implemented + * to work around this issue and allow installing a special + * handler for idle state index 0. + */ + drv->states[0].exit_latency = 1; + drv->states[0].target_residency = 1; + drv->states[0].flags = CPUIDLE_FLAG_TIME_VALID; + strncpy(drv->states[0].name, "ARM WFI", CPUIDLE_NAME_LEN); + strncpy(drv->states[0].desc, "ARM WFI", CPUIDLE_DESC_LEN); + + drv->cpumask = (struct cpumask *) cpu_possible_mask; + /* + * Start at index 1, request idle state nodes to be filled + */ + ret = of_init_idle_driver(drv, state_nodes, 1, true); + if (ret) + return ret; + + if (suspend_init->init_fn(drv, state_nodes)) + return -EOPNOTSUPP; + + for (i = 0; i < drv->state_count; i++) + drv->states[i].enter = arm_enter_idle_state; + + return cpuidle_register(drv, NULL); +} +device_initcall(arm64_idle_init);