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PSCI: Add initial support for PSCIv0.2 functions
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The PSCIv0.2 spec defines standard values of function IDs
and introduces a few new functions. Detect version of PSCI
and appropriately select the right PSCI functions.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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Ashwin Chaugule committed May 15, 2014
1 parent 4447a20 commit e71246a
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Showing 4 changed files with 328 additions and 77 deletions.
7 changes: 5 additions & 2 deletions arch/arm/include/asm/psci.h
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Original file line number Diff line number Diff line change
Expand Up @@ -29,16 +29,19 @@ struct psci_operations {
int (*cpu_off)(struct psci_power_state state);
int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
int (*migrate)(unsigned long cpuid);
int (*affinity_info)(unsigned long target_affinity,
unsigned long lowest_affinity_level);
int (*migrate_info_type)(void);
};

extern struct psci_operations psci_ops;
extern struct smp_operations psci_smp_ops;

#ifdef CONFIG_ARM_PSCI
void psci_init(void);
int psci_init(void);
bool psci_smp_available(void);
#else
static inline void psci_init(void) { }
static inline int psci_init(void) { }
static inline bool psci_smp_available(void) { return false; }
#endif

Expand Down
196 changes: 159 additions & 37 deletions arch/arm/kernel/psci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,63 +17,58 @@

#include <linux/init.h>
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/pm.h>
#include <uapi/linux/psci.h>

#include <asm/compiler.h>
#include <asm/errno.h>
#include <asm/opcodes-sec.h>
#include <asm/opcodes-virt.h>
#include <asm/psci.h>
#include <asm/system_misc.h>

struct psci_operations psci_ops;

static int (*invoke_psci_fn)(u32, u32, u32, u32);
typedef int (*psci_initcall_t)(const struct device_node *);

enum psci_function {
PSCI_FN_CPU_SUSPEND,
PSCI_FN_CPU_ON,
PSCI_FN_CPU_OFF,
PSCI_FN_MIGRATE,
PSCI_FN_AFFINITY_INFO,
PSCI_FN_MIGRATE_INFO_TYPE,
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

static int psci_to_linux_errno(int errno)
{
switch (errno) {
case PSCI_RET_SUCCESS:
return 0;
case PSCI_RET_EOPNOTSUPP:
case PSCI_RET_NOT_SUPPORTED:
return -EOPNOTSUPP;
case PSCI_RET_EINVAL:
case PSCI_RET_INVALID_PARAMS:
return -EINVAL;
case PSCI_RET_EPERM:
case PSCI_RET_DENIED:
return -EPERM;
};

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);
return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
& PSCI_0_2_POWER_STATE_ID_MASK) |
((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
& PSCI_0_2_POWER_STATE_TYPE_MASK) |
((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
& PSCI_0_2_POWER_STATE_AFFL_MASK);
}

/*
Expand Down Expand Up @@ -110,6 +105,14 @@ static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1,
return function_id;
}

static int psci_get_version(void)
{
int err;

err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
return err;
}

static int psci_cpu_suspend(struct psci_power_state state,
unsigned long entry_point)
{
Expand Down Expand Up @@ -153,37 +156,136 @@ static int psci_migrate(unsigned long cpuid)
return psci_to_linux_errno(err);
}

static const struct of_device_id psci_of_match[] __initconst = {
{ .compatible = "arm,psci", },
{},
};
static int psci_affinity_info(unsigned long target_affinity,
unsigned long lowest_affinity_level)
{
int err;
u32 fn;

fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
return err;
}

void __init psci_init(void)
static int psci_migrate_info_type(void)
{
struct device_node *np;
const char *method;
u32 id;
int err;
u32 fn;

np = of_find_matching_node(NULL, psci_of_match);
if (!np)
return;
fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
err = invoke_psci_fn(fn, 0, 0, 0);
return err;
}

static int get_set_conduit_method(struct device_node *np)
{
const char *method;

pr_info("probing function IDs from device-tree\n");
pr_info("probing for conduit method from DT.\n");

if (of_property_read_string(np, "method", &method)) {
pr_warning("missing \"method\" property\n");
goto out_put_node;
pr_warn("missing \"method\" property\n");
return -ENXIO;
}

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);
pr_warn("invalid \"method\" property: %s\n", method);
return -EINVAL;
}
return 0;
}

static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
{
invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
}

static void psci_sys_poweroff(void)
{
invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
}

/*
* PSCI Function IDs for v0.2+ are well defined so use
* standard values.
*/
static int psci_0_2_init(struct device_node *np)
{
int err, ver;

err = get_set_conduit_method(np);

if (err)
goto out_put_node;

ver = psci_get_version();

if (ver == PSCI_RET_NOT_SUPPORTED) {
/* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
err = -EOPNOTSUPP;
goto out_put_node;
} else {
pr_info("PSCIv%d.%d detected in firmware.\n",
PSCI_VERSION_MAJOR(ver),
PSCI_VERSION_MINOR(ver));

if (PSCI_VERSION_MAJOR(ver) == 0 &&
PSCI_VERSION_MINOR(ver) < 2) {
err = -EINVAL;
pr_err("Conflicting PSCI version detected.\n");
goto out_put_node;
}
}

pr_info("Using standard PSCI v0.2 function IDs\n");
psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN_CPU_SUSPEND;
psci_ops.cpu_suspend = psci_cpu_suspend;

psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
psci_ops.cpu_off = psci_cpu_off;

psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN_CPU_ON;
psci_ops.cpu_on = psci_cpu_on;

psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN_MIGRATE;
psci_ops.migrate = psci_migrate;

psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN_AFFINITY_INFO;
psci_ops.affinity_info = psci_affinity_info;

psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
PSCI_0_2_FN_MIGRATE_INFO_TYPE;
psci_ops.migrate_info_type = psci_migrate_info_type;

arm_pm_restart = psci_sys_reset;

pm_power_off = psci_sys_poweroff;

out_put_node:
of_node_put(np);
return err;
}

/*
* PSCI < v0.2 get PSCI Function IDs via DT.
*/
static int psci_0_1_init(struct device_node *np)
{
u32 id;
int err;

err = get_set_conduit_method(np);

if (err)
goto out_put_node;

pr_info("Using PSCI v0.1 Function IDs from DT\n");

if (!of_property_read_u32(np, "cpu_suspend", &id)) {
psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
psci_ops.cpu_suspend = psci_cpu_suspend;
Expand All @@ -206,5 +308,25 @@ void __init psci_init(void)

out_put_node:
of_node_put(np);
return;
return err;
}

static const struct of_device_id psci_of_match[] __initconst = {
{ .compatible = "arm,psci", .data = psci_0_1_init},
{ .compatible = "arm,psci-0.2", .data = psci_0_2_init},
{},
};

int __init psci_init(void)
{
struct device_node *np;
const struct of_device_id *matched_np;
psci_initcall_t init_fn;

np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
if (!np)
return -ENODEV;

init_fn = (psci_initcall_t)matched_np->data;
return init_fn(np);
}
2 changes: 1 addition & 1 deletion arch/arm64/include/asm/psci.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,6 @@
#ifndef __ASM_PSCI_H
#define __ASM_PSCI_H

void psci_init(void);
int psci_init(void);

#endif /* __ASM_PSCI_H */
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