diff options
Diffstat (limited to 'arch/arm/kernel/psci.c')
| -rw-r--r-- | arch/arm/kernel/psci.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c new file mode 100644 index 000000000000..1180801468d8 --- /dev/null +++ b/arch/arm/kernel/psci.c @@ -0,0 +1,253 @@ +/* + * 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> + */ + +#define pr_fmt(fmt) "psci: " fmt + +#include <linux/init.h> +#include <linux/of.h> +#include <linux/string.h> + +#include <asm/compiler.h> +#include <asm/errno.h> +#include <asm/opcodes-sec.h> +#include <asm/opcodes-virt.h> +#include <asm/psci.h> + +struct psci_operations psci_ops; + +/* Type of psci support. Currently can only be enabled or disabled */ +#define PSCI_SUP_DISABLED 0 +#define PSCI_SUP_ENABLED 1 + +static unsigned int psci; +static int (*invoke_psci_fn)(u32, u32, u32, u32); + +enum psci_function { + PSCI_FN_CPU_SUSPEND, + PSCI_FN_CPU_ON, + PSCI_FN_CPU_OFF, + PSCI_FN_MIGRATE, + PSCI_FN_MAX, +}; + +static u32 psci_function_id[PSCI_FN_MAX]; + +#define PSCI_RET_SUCCESS 0 +#define PSCI_RET_EOPNOTSUPP -1 +#define PSCI_RET_EINVAL -2 +#define PSCI_RET_EPERM -3 +#define PSCI_RET_EALREADYON -4 + +static int psci_to_linux_errno(int errno) +{ + switch (errno) { + case PSCI_RET_SUCCESS: + return 0; + case PSCI_RET_EOPNOTSUPP: + return -EOPNOTSUPP; + case PSCI_RET_EINVAL: + return -EINVAL; + case PSCI_RET_EPERM: + return -EPERM; + case PSCI_RET_EALREADYON: + return -EAGAIN; + }; + + return -EINVAL; +} + +#define PSCI_POWER_STATE_ID_MASK 0xffff +#define PSCI_POWER_STATE_ID_SHIFT 0 +#define PSCI_POWER_STATE_TYPE_MASK 0x1 +#define PSCI_POWER_STATE_TYPE_SHIFT 16 +#define PSCI_POWER_STATE_AFFL_MASK 0x3 +#define PSCI_POWER_STATE_AFFL_SHIFT 24 + +static u32 psci_power_state_pack(struct psci_power_state state) +{ + return ((state.id & PSCI_POWER_STATE_ID_MASK) + << PSCI_POWER_STATE_ID_SHIFT) | + ((state.type & PSCI_POWER_STATE_TYPE_MASK) + << PSCI_POWER_STATE_TYPE_SHIFT) | + ((state.affinity_level & PSCI_POWER_STATE_AFFL_MASK) + << PSCI_POWER_STATE_AFFL_SHIFT); +} + +/* + * The following two functions are invoked via the invoke_psci_fn pointer + * and will not be inlined, allowing us to piggyback on the AAPCS. + */ +static noinline int __invoke_psci_fn_hvc(u32 function_id, u32 arg0, u32 arg1, + u32 arg2) +{ + asm volatile( + __asmeq("%0", "r0") + __asmeq("%1", "r1") + __asmeq("%2", "r2") + __asmeq("%3", "r3") + __HVC(0) + : "+r" (function_id) + : "r" (arg0), "r" (arg1), "r" (arg2)); + + return function_id; +} + +static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1, + u32 arg2) +{ + asm volatile( + __asmeq("%0", "r0") + __asmeq("%1", "r1") + __asmeq("%2", "r2") + __asmeq("%3", "r3") + __SMC(0) + : "+r" (function_id) + : "r" (arg0), "r" (arg1), "r" (arg2)); + + return function_id; +} + +static int psci_cpu_suspend(struct psci_power_state state, + unsigned long entry_point) +{ + int err; + u32 fn, power_state; + + fn = psci_function_id[PSCI_FN_CPU_SUSPEND]; + power_state = psci_power_state_pack(state); + err = invoke_psci_fn(fn, power_state, entry_point, 0); + return psci_to_linux_errno(err); +} + +static int psci_cpu_off(struct psci_power_state state) +{ + int err; + u32 fn, power_state; + + fn = psci_function_id[PSCI_FN_CPU_OFF]; + power_state = psci_power_state_pack(state); + err = invoke_psci_fn(fn, power_state, 0, 0); + return psci_to_linux_errno(err); +} + +static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point) +{ + int err; + u32 fn; + + fn = psci_function_id[PSCI_FN_CPU_ON]; + err = invoke_psci_fn(fn, cpuid, entry_point, 0); + return psci_to_linux_errno(err); +} + +static int psci_migrate(unsigned long cpuid) +{ + int err; + u32 fn; + + fn = psci_function_id[PSCI_FN_MIGRATE]; + err = invoke_psci_fn(fn, cpuid, 0, 0); + return psci_to_linux_errno(err); +} + +static const struct of_device_id psci_of_match[] __initconst = { + { .compatible = "arm,psci", }, + {}, +}; + +static int __init psci_init(void) +{ + struct device_node *np; + const char *method; + u32 id; + + if (psci == PSCI_SUP_DISABLED) + return 0; + + np = of_find_matching_node(NULL, psci_of_match); + if (!np) + return 0; + + pr_info("probing function IDs from device-tree\n"); + + if (of_property_read_string(np, "method", &method)) { + pr_warning("missing \"method\" property\n"); + goto out_put_node; + } + + if (!strcmp("hvc", method)) { + invoke_psci_fn = __invoke_psci_fn_hvc; + } else if (!strcmp("smc", method)) { + invoke_psci_fn = __invoke_psci_fn_smc; + } else { + pr_warning("invalid \"method\" property: %s\n", method); + goto out_put_node; + } + + if (!of_property_read_u32(np, "cpu_suspend", &id)) { + psci_function_id[PSCI_FN_CPU_SUSPEND] = id; + psci_ops.cpu_suspend = psci_cpu_suspend; + } + + if (!of_property_read_u32(np, "cpu_off", &id)) { + psci_function_id[PSCI_FN_CPU_OFF] = id; + psci_ops.cpu_off = psci_cpu_off; + } + + if (!of_property_read_u32(np, "cpu_on", &id)) { + psci_function_id[PSCI_FN_CPU_ON] = id; + psci_ops.cpu_on = psci_cpu_on; + } + + if (!of_property_read_u32(np, "migrate", &id)) { + psci_function_id[PSCI_FN_MIGRATE] = id; + psci_ops.migrate = psci_migrate; + } + +out_put_node: + of_node_put(np); + return 0; +} +early_initcall(psci_init); + +int __init psci_probe(void) +{ + struct device_node *np; + int ret = -ENODEV; + + if (psci == PSCI_SUP_ENABLED) { + np = of_find_matching_node(NULL, psci_of_match); + if (np) + ret = 0; + } + + of_node_put(np); + return ret; +} + +static int __init early_psci(char *val) +{ + int ret = 0; + + if (strcmp(val, "enable") == 0) + psci = PSCI_SUP_ENABLED; + else if (strcmp(val, "disable") == 0) + psci = PSCI_SUP_DISABLED; + else + ret = -EINVAL; + + return ret; +} +early_param("psci", early_psci); |