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ARM: psci: add probe function to discover presence of a psci implementation

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This patch adds a probe function to check if the secure firmware has an
implementation of the Power State Coordination Interface.

'bL_platform_power_ops' will be implemented by:

a. a native backend when Linux runs in secure world
b. a psci backend which relies on the secure firmware to implement the
   power ops

presence of b. will be indicated by the psci device node in the device tree.
The device node is expected to be populated by the secure firmware if it
supports psci. If the native backend detects a psci node then it bails out
allowing the psci backend to be registered.

Also a dummy 'psci_probe' function is added for the case when psci support
is not included. This prevents the build from breaking for tc2 and the
rtsm platforms.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
This commit is contained in:
Achin Gupta
2012-12-16 23:11:32 +00:00
committed by Jon Medhurst
parent 4e57b6c98d
commit 25366fe14f
2 changed files with 21 additions and 0 deletions
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8
arch/arm/include/asm/psci.h
View File

@@ -37,4 +37,12 @@ struct psci_operations {
extern struct psci_operations psci_ops;
#ifdef CONFIG_ARM_PSCI
extern int __init psci_probe(void);
#else
static inline int psci_probe(void)
{
return -ENODEV;
}
#endif
#endif /* __ASM_ARM_PSCI_H */

13
arch/arm/kernel/psci.c
View File

@@ -212,3 +212,16 @@ out_put_node:
return 0;
}
early_initcall(psci_init);
int __init psci_probe(void)
{
struct device_node *np;
int ret = -ENODEV;
np = of_find_matching_node(NULL, psci_of_match);
if (np)
ret = 0;
of_node_put(np);
return ret;
}