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Diffstat (limited to 'arch/arm/kernel/psci.c')
-rw-r--r--arch/arm/kernel/psci.c49
1 files changed, 45 insertions, 4 deletions
diff --git a/arch/arm/kernel/psci.c b/arch/arm/kernel/psci.c
index 36531643cc2c..0daf4f252284 100644
--- a/arch/arm/kernel/psci.c
+++ b/arch/arm/kernel/psci.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/of.h>
+#include <linux/string.h>
#include <asm/compiler.h>
#include <asm/errno.h>
@@ -26,6 +27,11 @@
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 {
@@ -42,6 +48,7 @@ static u32 psci_function_id[PSCI_FN_MAX];
#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)
{
@@ -54,6 +61,8 @@ static int psci_to_linux_errno(int errno)
return -EINVAL;
case PSCI_RET_EPERM:
return -EPERM;
+ case PSCI_RET_EALREADYON:
+ return -EAGAIN;
};
return -EINVAL;
@@ -158,15 +167,18 @@ static const struct of_device_id psci_of_match[] __initconst = {
{},
};
-static int __init psci_init(void)
+void __init psci_init(void)
{
struct device_node *np;
const char *method;
u32 id;
+ if (psci == PSCI_SUP_DISABLED)
+ return;
+
np = of_find_matching_node(NULL, psci_of_match);
if (!np)
- return 0;
+ return;
pr_info("probing function IDs from device-tree\n");
@@ -206,6 +218,35 @@ static int __init psci_init(void)
out_put_node:
of_node_put(np);
- return 0;
+ return;
+}
+
+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_initcall(psci_init);
+early_param("psci", early_psci);