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 @@ -80,6 +80,33 @@ 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