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| author | Alexander Steffen <Alexander.Steffen@infineon.com> | 2022-06-08 19:31:12 +0200 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko@kernel.org> | 2022-08-03 23:56:19 +0300 |
| commit | f25534a68b8e1ed8266d23b464a3b512364b124d (patch) | |
| tree | e6b0e4eca4ed8a8f8ed6c70e6c28ffa4da8a6197 /drivers/char | |
| parent | 2353673d8a025a6ba3b3aa3917a3a98944e64702 (diff) | |
| download | lwn-f25534a68b8e1ed8266d23b464a3b512364b124d.tar.gz lwn-f25534a68b8e1ed8266d23b464a3b512364b124d.zip | |
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: 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>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/tpm/tpm_tis_core.c | 14 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm_tis_core.h | 10 |
2 files changed, 24 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index dc56b976d816..757623bacfd5 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -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) diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index 6c203f36b8a1..66a5a13cd1df 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -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 |