Commit f25534a6 authored by Alexander Steffen's avatar Alexander Steffen Committed by Jarkko Sakkinen
Browse files

tpm: Add tpm_tis_verify_crc to the tpm_tis_phy_ops protocol layer 



Some TPMs, e.g. those implementing the I2C variant of TIS, can verify
data transfers to/from the FIFO with a CRC. The CRC is calculated over
the entirety of the FIFO register. Since the phy_ops layer is not aware
when the core layer is done reading/writing the FIFO, CRC verification
must be triggered from the core layer. To this end, add an optional
phy_ops API call.

Co-developed-by: default avatarJohannes Holland <johannes.holland@infineon.com>
Signed-off-by: default avatarJohannes Holland <johannes.holland@infineon.com>
Signed-off-by: default avatarAlexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 2353673d

drivers/char/tpm/tpm_tis_core.c

+14 −0
Original line number Diff line number Diff line
@@ -289,6 +289,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) 
	int size = 0;

	int status;

	u32 expected;

	int rc;



	if (count < TPM_HEADER_SIZE) {

		size = -EIO;
@@ -328,6 +329,13 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) 
		goto out;

	}



	rc = tpm_tis_verify_crc(priv, (size_t)size, buf);

	if (rc < 0) {

		dev_err(&chip->dev, "CRC mismatch for response.\n");

		size = rc;

		goto out;

	}



out:

	tpm_tis_ready(chip);

	return size;
@@ -443,6 +451,12 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) 
	if (rc < 0)

		return rc;



	rc = tpm_tis_verify_crc(priv, len, buf);

	if (rc < 0) {

		dev_err(&chip->dev, "CRC mismatch for command.\n");

		return rc;

	}



	/* go and do it */

	rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);

	if (rc < 0)

drivers/char/tpm/tpm_tis_core.h

+10 −0
Original line number Diff line number Diff line
@@ -121,6 +121,8 @@ struct tpm_tis_phy_ops { 
			  u8 *result, enum tpm_tis_io_mode mode);

	int (*write_bytes)(struct tpm_tis_data *data, u32 addr, u16 len,

			   const u8 *value, enum tpm_tis_io_mode mode);

	int (*verify_crc)(struct tpm_tis_data *data, size_t len,

			  const u8 *value);

};



static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr,
@@ -188,6 +190,14 @@ static inline int tpm_tis_write32(struct tpm_tis_data *data, u32 addr, 
	return rc;

}



static inline int tpm_tis_verify_crc(struct tpm_tis_data *data, size_t len,

				     const u8 *value)

{

	if (!data->phy_ops->verify_crc)

		return 0;

	return data->phy_ops->verify_crc(data, len, value);

}



static inline bool is_bsw(void)

{

#ifdef CONFIG_X86