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tpm: Add tpm_tis_verify_crc to the tpm_tis_phy_ops protocol layer

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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: Johannes Holland <johannes.holland@infineon.com>
Signed-off-by: Johannes Holland <johannes.holland@infineon.com>
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This commit is contained in:
Alexander Steffen 2022-06-08 19:31:12 +02:00 committed by Jarkko Sakkinen
parent 2353673d8a
commit f25534a68b
2 changed files with 24 additions and 0 deletions
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14
drivers/char/tpm/tpm_tis_core.c
View file

@ -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)

10
drivers/char/tpm/tpm_tis_core.h
View file

@ -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