[PATCH v10 3/8] tpm: tpm_tis: Add retry in case of protocol failure or data integrity (on I2C only) failure.
From: amirmizi6
Date: Thu Jun 04 2020 - 09:48:41 EST
From: Amir Mizinski <amirmizi6@xxxxxxxxx>
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 <christophe-h.ricard@xxxxxx>
Signed-off-by: Christophe Ricard <christophe-h.ricard@xxxxxx>
Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
---
drivers/char/tpm/tpm_tis_core.c | 106 ++++++++++++++++++++++++----------------
drivers/char/tpm/tpm_tis_core.h | 3 ++
2 files changed, 67 insertions(+), 42 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 6ea70ea..202714d 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -308,7 +308,7 @@ 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) {
@@ -316,39 +316,53 @@ 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(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(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;
@@ -372,7 +386,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
TPM_STS_COMMAND_READY, chip->timeout_b,
&priv->int_queue, false) < 0) {
rc = -ETIME;
- goto out_err;
+ return rc;
}
}
@@ -381,13 +395,13 @@ 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;
}
@@ -395,14 +409,10 @@ 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)
@@ -431,13 +441,25 @@ 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