This patchset introduces some functions as defined in the PSCI v0.2 spec and a corresponding DT binding to differentiate it from previous PSCI versions. Since PSCIv0.2 has standard function IDs, it is possible to statically assign them rather than depend on values from DT.
This patchset depends on the PSCI header (/uapi/linux/psci.h) introduced by http://www.spinics.net/lists/arm-kernel/msg319712.html
Changes in v7: - Add two new functions: SYSTEM_OFF and SYSTEM_RESET as defined in PSCIv0.2. - Added a delay before calling cpu_kill to avoid race with cpu_die.
Changes in v6: - rebase on top of uapi/linux/psci.h introduced by Anups patch http://www.spinics.net/lists/arm-kernel/msg319712.html - rebase on top of Catalins tree tip.
Changes in v5: - Add uapi/linux/psci.h to kbuild - ret with err if PSCI_ID_VERSION is not implemented.
Changes in v4: - Correct copyright banner format. - Check if PSCI Version ID is supported. - Add all PSCI RET codes in uapi header. - Explicitely ret 1 from psci_cpu_kill()
Changes in v3: - Roll up common functionality for getting conduit method. - Remove #defines for ARM32 and ARM64 in uapi/linux/psci.h - Remove functions not supported by PSCI v0.1 - Misc cleanups. - Add PSCI_AFFINITY_INFO return types in uapi header. - Changed function names for PSCI v0.1 and PSCI v0.2 - Added copyright info to uapi header. - Fixed args to affinity_info call. - Fix typo in psci_init definition when PSCI is not defined.
Changes in v2:
- Add AFFINITY_INFO and MIGRATE_INFO_TYPE functions. - Add binding Documentation. - Add function to get PSCI version. - Add common #defines in uapi/linux/psci.h - Implement cpu_kill and check if CPU is dead via AFFINITY_INFO. - Misc cleanups.
Changes in v1:
- Add new binding "arm, psci-0.2" - Separate conduit and PSCI function assignment methods.
*** BLURB HERE ***
Ashwin Chaugule (3): PSCI: Add initial support for PSCIv0.2 functions Documentation: devicetree: Add new binding for PSCIv0.2 ARM: Check if a CPU has gone offline
Documentation/devicetree/bindings/arm/psci.txt | 35 ++++- arch/arm/include/asm/psci.h | 7 +- arch/arm/kernel/psci.c | 196 +++++++++++++++++++----- arch/arm/kernel/psci_smp.c | 32 ++++ arch/arm64/include/asm/psci.h | 2 +- arch/arm64/kernel/psci.c | 200 ++++++++++++++++++++----- include/uapi/linux/psci.h | 5 + 7 files changed, 399 insertions(+), 78 deletions(-)
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 --- arch/arm/include/asm/psci.h | 7 +- arch/arm/kernel/psci.c | 196 +++++++++++++++++++++++++++++++++-------- arch/arm64/include/asm/psci.h | 2 +- arch/arm64/kernel/psci.c | 200 ++++++++++++++++++++++++++++++++++-------- 4 files changed, 328 insertions(+), 77 deletions(-)
diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h index c4ae171..b93e34a 100644 --- a/arch/arm/include/asm/psci.h +++ b/arch/arm/include/asm/psci.h @@ -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
diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c index 4693188..3775e62 100644 --- a/arch/arm/kernel/psci.c +++ b/arch/arm/kernel/psci.c @@ -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_MASK) + << PSCI_0_2_POWER_STATE_ID_SHIFT) | + ((state.type & PSCI_0_2_POWER_STATE_TYPE_MASK) + << PSCI_0_2_POWER_STATE_TYPE_SHIFT) | + ((state.affinity_level & PSCI_0_2_POWER_STATE_AFFL_MASK) + << PSCI_0_2_POWER_STATE_AFFL_SHIFT); }
/* @@ -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) { @@ -153,26 +156,36 @@ 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)) { @@ -180,10 +193,99 @@ void __init psci_init(void) } 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; @@ -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); } diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h index d15ab8b4..e5312ea 100644 --- a/arch/arm64/include/asm/psci.h +++ b/arch/arm64/include/asm/psci.h @@ -14,6 +14,6 @@ #ifndef __ASM_PSCI_H #define __ASM_PSCI_H
-void psci_init(void); +int psci_init(void);
#endif /* __ASM_PSCI_H */ diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index ea4828a..6045613 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -18,12 +18,16 @@ #include <linux/init.h> #include <linux/of.h> #include <linux/smp.h> +#include <linux/reboot.h> +#include <linux/pm.h> +#include <uapi/linux/psci.h>
#include <asm/compiler.h> #include <asm/cpu_ops.h> #include <asm/errno.h> #include <asm/psci.h> #include <asm/smp_plat.h> +#include <asm/system_misc.h>
#define PSCI_POWER_STATE_TYPE_STANDBY 0 #define PSCI_POWER_STATE_TYPE_POWER_DOWN 1 @@ -40,58 +44,52 @@ 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); };
static struct psci_operations psci_ops;
static int (*invoke_psci_fn)(u64, u64, u64, u64); +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_MASK) + << PSCI_0_2_POWER_STATE_ID_SHIFT) | + ((state.type & PSCI_0_2_POWER_STATE_TYPE_MASK) + << PSCI_0_2_POWER_STATE_TYPE_SHIFT) | + ((state.affinity_level & PSCI_0_2_POWER_STATE_AFFL_MASK) + << PSCI_0_2_POWER_STATE_AFFL_SHIFT); }
/* @@ -128,6 +126,14 @@ static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 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) { @@ -171,26 +177,36 @@ 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)) { @@ -198,10 +214,99 @@ void __init psci_init(void) } 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_FN64_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_FN64_CPU_ON; + psci_ops.cpu_on = psci_cpu_on; + + psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE; + psci_ops.migrate = psci_migrate; + + psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_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; @@ -224,7 +329,28 @@ 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); }
#ifdef CONFIG_SMP
The PSCI v0.2+ spec defines standard values for PSCI function IDs. Add a new binding entry so that pre v0.2 implementations can use DT entries for function IDs and v0.2+ implementations use standard entries as defined by the PSCIv0.2 specification.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org Acked-by: Rob Herring robh@kernel.org --- Documentation/devicetree/bindings/arm/psci.txt | 35 +++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt index 433afe9..d01a90b 100644 --- a/Documentation/devicetree/bindings/arm/psci.txt +++ b/Documentation/devicetree/bindings/arm/psci.txt @@ -21,7 +21,15 @@ to #0.
Main node required properties:
- - compatible : Must be "arm,psci" + - compatible : should contain at least one of: + + * "arm,psci" : for implementations complying to PSCI versions prior to + 0.2. For these cases function IDs must be provided. + + * "arm,psci-0.2" : for implementations complying to PSCI 0.2. Function + IDs are not required and should be ignored by an OS with PSCI 0.2 + support, but are permitted to be present for compatibility with + existing software when "arm,psci" is later in the compatible list.
- method : The method of calling the PSCI firmware. Permitted values are: @@ -45,6 +53,8 @@ Main node optional properties:
Example:
+Case 1: PSCI v0.1 only. + psci { compatible = "arm,psci"; method = "smc"; @@ -53,3 +63,26 @@ Example: cpu_on = <0x95c10002>; migrate = <0x95c10003>; }; + + +Case 2: PSCI v0.2 only + + psci { + compatible = "arm,psci-0.2"; + method = "smc"; + }; + +Case 3: PSCI v0.2 and PSCI v0.1. + + As described above, for compatibility with existing kernels, the + hypervisor will likely want to provide IDs, e.g. + + psci { + compatible = "arm,psci-0.2", "arm,psci"; + method = "hvc"; + + cpu_on = < arbitrary value >; + cpu_off = < arbitrary value >; + + ... + };
PSCIv0.2 adds a new function called AFFINITY_INFO, which can be used to query if a specified CPU has actually gone offline. Calling this function via cpu_kill ensures that a CPU has quiesced after a call to cpu_die.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org Reviewed-by: Rob Herring robh@kernel.org --- arch/arm/kernel/psci_smp.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/psci.h | 5 +++++ 2 files changed, 37 insertions(+)
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c index 570a48c..0b1882b 100644 --- a/arch/arm/kernel/psci_smp.c +++ b/arch/arm/kernel/psci_smp.c @@ -16,6 +16,8 @@ #include <linux/init.h> #include <linux/smp.h> #include <linux/of.h> +#include <linux/delay.h> +#include <uapi/linux/psci.h>
#include <asm/psci.h> #include <asm/smp_plat.h> @@ -66,6 +68,35 @@ void __ref psci_cpu_die(unsigned int cpu) /* We should never return */ panic("psci: cpu %d failed to shutdown\n", cpu); } + +int __ref psci_cpu_kill(unsigned int cpu) +{ + int err, retry = 0; + + 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 once more if it fails. + */ +retry_once: + err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); + + if (err != PSCI_AFFINITY_INFO_RET_OFF) { + if (!retry++) { + msleep(100); + pr_info("Retrying once more to check for CPU kill\n"); + goto retry_once; + } + pr_err("psci: Cannot kill CPU:%d, psci ret val: %d\n", + cpu, err); + /* Make platform_cpu_kill() fail. */ + return 0; + } + return 1; +} + #endif
bool __init psci_smp_available(void) @@ -78,5 +109,6 @@ struct smp_operations __initdata psci_smp_ops = { .smp_boot_secondary = psci_boot_secondary, #ifdef CONFIG_HOTPLUG_CPU .cpu_die = psci_cpu_die, + .cpu_kill = psci_cpu_kill, #endif }; diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h index a4136c3..857209b 100644 --- a/include/uapi/linux/psci.h +++ b/include/uapi/linux/psci.h @@ -74,4 +74,9 @@ #define PSCI_RET_NOT_PRESENT -7 #define PSCI_RET_DISABLED -8
+/* Return values from the PSCI_ID_AFFINITY_INFO Function. */ +#define PSCI_AFFINITY_INFO_RET_ON 0 +#define PSCI_AFFINITY_INFO_RET_OFF 1 +#define PSCI_AFFINITY_INFO_RET_ON_PENDING 2 + #endif /* _UAPI_LINUX_PSCI_H */
On Fri, Apr 25, 2014 at 12:27 PM, Ashwin Chaugule ashwin.chaugule@linaro.org wrote:
PSCIv0.2 adds a new function called AFFINITY_INFO, which can be used to query if a specified CPU has actually gone offline. Calling this function via cpu_kill ensures that a CPU has quiesced after a call to cpu_die.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org Reviewed-by: Rob Herring robh@kernel.org
arch/arm/kernel/psci_smp.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/psci.h | 5 +++++ 2 files changed, 37 insertions(+)
[...]
+retry_once:
err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);if (err != PSCI_AFFINITY_INFO_RET_OFF) {if (!retry++) {msleep(100);
It would be better to sleep 10ms 10 times rather than a single 100ms sleep. And please do this with a loop rather than a goto.
Rob
On 25 April 2014 14:01, Rob Herring robherring2@gmail.com wrote:
On Fri, Apr 25, 2014 at 12:27 PM, Ashwin Chaugule ashwin.chaugule@linaro.org wrote:
PSCIv0.2 adds a new function called AFFINITY_INFO, which can be used to query if a specified CPU has actually gone offline. Calling this function via cpu_kill ensures that a CPU has quiesced after a call to cpu_die.
Signed-off-by: Ashwin Chaugule ashwin.chaugule@linaro.org Reviewed-by: Rob Herring robh@kernel.org
arch/arm/kernel/psci_smp.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/psci.h | 5 +++++ 2 files changed, 37 insertions(+)
[...]
+retry_once:
err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);if (err != PSCI_AFFINITY_INFO_RET_OFF) {if (!retry++) {msleep(100);It would be better to sleep 10ms 10 times rather than a single 100ms sleep. And please do this with a loop rather than a goto.
Fixed in v8.
Cheers, Ashwin
-
Ashwin Chaugule -
Rob Herring