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-rw-r--r--drivers/char/tpm/tpm-chip.c27
-rw-r--r--include/linux/tpm.h5
2 files changed, 32 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 242b716aed5e..f551061262c9 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -81,6 +81,33 @@ void tpm_put_ops(struct tpm_chip *chip)
EXPORT_SYMBOL_GPL(tpm_put_ops);
/**
+ * tpm_default_chip() - find a TPM chip and get a reference to it
+ */
+struct tpm_chip *tpm_default_chip(void)
+{
+ struct tpm_chip *chip, *res = NULL;
+ int chip_num = 0;
+ int chip_prev;
+
+ mutex_lock(&idr_lock);
+
+ do {
+ chip_prev = chip_num;
+ chip = idr_get_next(&dev_nums_idr, &chip_num);
+ if (chip) {
+ get_device(&chip->dev);
+ res = chip;
+ break;
+ }
+ } while (chip_prev != chip_num);
+
+ mutex_unlock(&idr_lock);
+
+ return res;
+}
+EXPORT_SYMBOL_GPL(tpm_default_chip);
+
+/**
* tpm_find_get_ops() - find and reserve a TPM chip
* @chip: a &struct tpm_chip instance, %NULL for the default chip
*
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 8eb5e5ebe136..4609b94142d4 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -63,6 +63,7 @@ extern int tpm_seal_trusted(struct tpm_chip *chip,
extern int tpm_unseal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options);
+extern struct tpm_chip *tpm_default_chip(void);
#else
static inline int tpm_is_tpm2(struct tpm_chip *chip)
{
@@ -98,5 +99,9 @@ static inline int tpm_unseal_trusted(struct tpm_chip *chip,
{
return -ENODEV;
}
+static inline struct tpm_chip *tpm_default_chip(void)
+{
+ return NULL;
+}
#endif
#endif