On Thu, Jun 25, 2020 at 05:46:44PM +0300, amirmizi6@xxxxxxxxx wrote:
> From: Amir Mizinski <amirmizi6@xxxxxxxxx>
>
> When using I2C bus protocol, the TPM has the ability to report data
> integrity on incoming or outgoing command parameter bytes.
> According to the TCG specs, if this data validation functionality is
> enabled via the TPM_DATA_CSUM_ENABLE register, the TPM will update the
> TPM_DATA_CSUM register after reception of the last command byte and after
> the last response byte has been read.
>
> Data integrity is checked if a "verify_data_integrity" handle is defined in
> "tpm_tis_phy_ops".
>
> Co-developed-by: Christophe Ricard <christophe-h.ricard@xxxxxx>
> Signed-off-by: Christophe Ricard <christophe-h.ricard@xxxxxx>
> Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
> ---
> drivers/char/tpm/tpm_tis_core.c | 14 ++++++++++++++
> drivers/char/tpm/tpm_tis_core.h | 2 ++
> 2 files changed, 16 insertions(+)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index e136467..347c020 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -347,6 +347,13 @@ static int __tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> return size;
> }
>
> + if (priv->phy_ops->verify_data_integrity)
> + if (!priv->phy_ops->verify_data_integrity(priv, buf,
> + size)) {
> + size = -EIO;
> + return size;
> + }
> +
> return size;
> }
>
> @@ -419,6 +426,13 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
> return rc;
> }
>
> + if (priv->phy_ops->verify_data_integrity) {
> + if (!priv->phy_ops->verify_data_integrity(priv, buf, len)) {
> + rc = -EIO;
> + return rc;
> + }
> + }
> +
> return 0;
> }
>
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 6cc6b76..cd97c01 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -107,6 +107,8 @@ struct tpm_tis_phy_ops {
> int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result);
> int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result);
> int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src);
> + bool (*verify_data_integrity)(struct tpm_tis_data *data, const u8 *buf,
> + size_t len);
> };
>
> static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr,
> --
> 2.7.4
>
As I've said before, I'm not too eager to add a new callback and nothing
in the commit message rationalizes adding one.
/Jarkko
