| Message ID | 20220525165849.7789-3-Alexander.Steffen@infineon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tpm_tis_i2c | expand |
On Wed, 2022-05-25 at 18:58 +0200, Alexander Steffen wrote: > 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> > --- > drivers/char/tpm/tpm_tis_core.c | 14 ++++++++++++++ > drivers/char/tpm/tpm_tis_core.h | 10 ++++++++++ > 2 files changed, 24 insertions(+) > > 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 Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> BR, Jarkko
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