From: Amir Mizinski <[email protected]> The FIFO protocol described in the TCG PC Client Device Driver Design Principles for TPM 2.0 advises retrying sending a command or receiving a response using the FIFO protocol in case of any error in the protocol.
Add a retry mechanism on any protocol error. In addition, in case of a data integrity issue in the I2C bus protocol, check after sending a command completion or receiving a response from the TPM. Co-developed-by: Christophe Ricard <[email protected]> Signed-off-by: Christophe Ricard <[email protected]> Signed-off-by: Amir Mizinski <[email protected]> --- drivers/char/tpm/tpm_tis_core.c | 107 ++++++++++++++++++++++++---------------- drivers/char/tpm/tpm_tis_core.h | 3 ++ 2 files changed, 67 insertions(+), 43 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index c725b68..97eae72 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -312,7 +312,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); int size = 0; - int status; + int status, i; u32 expected; if (count < TPM_HEADER_SIZE) { @@ -320,40 +320,53 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) goto out; } - size = recv_data(chip, buf, TPM_HEADER_SIZE); - /* read first 10 bytes, including tag, paramsize, and result */ - if (size < TPM_HEADER_SIZE) { - dev_err(&chip->dev, "Unable to read header\n"); - goto out; - } + for (i = 0; i < TPM_RETRY; i++) { + size = recv_data(chip, buf, TPM_HEADER_SIZE); + /* read first 10 bytes, including tag, paramsize, and result */ + if (size < TPM_HEADER_SIZE) { + dev_err(&chip->dev, "Unable to read header\n"); + goto retry; + } - expected = be32_to_cpu(*(__be32 *) (buf + 2)); - if (expected > count || expected < TPM_HEADER_SIZE) { - size = -EIO; - goto out; - } + expected = be32_to_cpu(*(__be32 *) (buf + 2)); + if (expected > count || expected < TPM_HEADER_SIZE) { + size = -EIO; + goto retry; + } - size += recv_data(chip, &buf[TPM_HEADER_SIZE], - expected - TPM_HEADER_SIZE); - if (size < expected) { - dev_err(&chip->dev, "Unable to read remainder of result\n"); - size = -ETIME; - goto out; - } + size += recv_data(chip, &buf[TPM_HEADER_SIZE], + expected - TPM_HEADER_SIZE); + if (size < expected) { + dev_err(&chip->dev, "Unable to read remainder of result\n"); + size = -ETIME; + goto retry; + } - if (wait_for_tpm_stat_result(chip, TPM_STS_VALID, - TPM_STS_VALID, chip->timeout_c, - &priv->int_queue, false) < 0) { - size = -ETIME; - goto out; - } - status = tpm_tis_status(chip); - if (status & TPM_STS_DATA_AVAIL) { /* retry? */ - dev_err(&chip->dev, "Error left over data\n"); - size = -EIO; - goto out; - } + if (wait_for_tpm_stat_result(chip, TPM_STS_VALID, + TPM_STS_VALID, chip->timeout_c, + &priv->int_queue, false) < 0) { + size = -ETIME; + goto retry; + } + status = tpm_tis_status(chip); + if (status & TPM_STS_DATA_AVAIL) { /* retry? */ + dev_err(&chip->dev, "Error left over data\n"); + size = -EIO; + goto retry; + } + + if (priv->phy_ops->verify_data_integrity) + if (!priv->phy_ops->verify_data_integrity(priv, buf, + size)) + size = -EIO; +retry: + if (size <= 0) + tpm_tis_write8(priv, TPM_STS(priv->locality), + TPM_STS_RESPONSE_RETRY); + else + goto out; + } out: tpm_tis_ready(chip); return size; @@ -378,7 +391,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) chip->timeout_b, &priv->int_queue, false) < 0) { rc = -ETIME; - goto out_err; + return rc; } } @@ -387,13 +400,13 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) if (burstcnt < 0) { dev_err(&chip->dev, "Unable to read burstcount\n"); rc = burstcnt; - goto out_err; + return rc; } burstcnt = min_t(int, burstcnt, len - count); rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality), burstcnt, buf + count); if (rc < 0) - goto out_err; + return rc; count += burstcnt; } @@ -401,14 +414,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) TPM_STS_VALID, chip->timeout_a, &priv->int_queue, false) < 0) { rc = -ETIME; - goto out_err; + return rc; } return 0; - -out_err: - tpm_tis_ready(chip); - return rc; } static void disable_interrupts(struct tpm_chip *chip) @@ -437,13 +446,25 @@ static void disable_interrupts(struct tpm_chip *chip) static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); - int rc; + int rc, i; u32 ordinal; unsigned long dur; - rc = tpm_tis_send_data(chip, buf, len); - if (rc < 0) - return rc; + for (i = 0; i < TPM_RETRY; i++) { + rc = tpm_tis_send_data(chip, buf, len); + if (rc < 0) + continue; + if (priv->phy_ops->verify_data_integrity) { + if (!priv->phy_ops->verify_data_integrity(priv, buf, + len)){ + rc = -EIO; + continue; + } + } + break; + } + if (i == TPM_RETRY) + goto out_err; /* go and do it */ rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO); diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index d06c65b..cd97c01 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -34,6 +34,7 @@ enum tis_status { TPM_STS_GO = 0x20, TPM_STS_DATA_AVAIL = 0x10, TPM_STS_DATA_EXPECT = 0x08, + TPM_STS_RESPONSE_RETRY = 0x02, }; enum tis_int_flags { @@ -106,6 +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
