On Thu, Jun 25, 2020 at 05:46:43PM +0300, [email protected] wrote: > From: Amir Mizinski <[email protected]> > > Added a retry mechanism on any protocol error when sending a command or > receiving a response. This was changed to comply with > the TCG PC Client Device Driver Design Principles for TPM 2.0.
We don't have to comply with this. > When sending a command, a loop is added in "tpm_tis_send_main()" that calls > "tpm_tis_send_data()" and then issues a retry attempt if any error occurs. > When receiving a response, the following new function derived from > "tpm_tis_recv()" is added: "__tpm_tis_recv()". "tpm_tis_recv()" is modified > to call "__tpm_tis_recv()" in a loop. If any error occurs, a retry is > initiated by setting TPM_STS.responseRetry and "__tpm_tis_recv()" is > called again. > In both cases a retry is attempted up to "TPM_RETRY" times. > > 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 | 62 > ++++++++++++++++++++++++++--------------- > drivers/char/tpm/tpm_tis_core.h | 1 + > 2 files changed, 41 insertions(+), 22 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 6b33620..e136467 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -305,29 +305,24 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, > size_t count) > return size; > } > > -static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) > +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; > u32 expected; > > - if (count < TPM_HEADER_SIZE) { > - size = -EIO; > - 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; > + return size; > } > > expected = be32_to_cpu(*(__be32 *) (buf + 2)); > if (expected > count || expected < TPM_HEADER_SIZE) { > size = -EIO; > - goto out; > + return size; > } > > size += recv_data(chip, &buf[TPM_HEADER_SIZE], > @@ -335,22 +330,45 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, > size_t count) > if (size < expected) { > dev_err(&chip->dev, "Unable to read remainder of result\n"); > size = -ETIME; > - goto out; > + return size; > } > > if (tpm_tis_wait_for_stat(chip, TPM_STS_VALID, TPM_STS_VALID, > chip->timeout_c, &priv->int_queue, > false) < 0) { > size = -ETIME; > - goto out; > + return size; > } > + > status = tpm_tis_status(chip); > if (status & TPM_STS_DATA_AVAIL) { /* retry? */ > dev_err(&chip->dev, "Error left over data\n"); > size = -EIO; > + return size; > + } > + > + return size; > +} > + > +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; > + int i; > + > + if (count < TPM_HEADER_SIZE) { > + size = -EIO; > goto out; > } > > + for (i = 0; i < TPM_RETRY; i++) { > + size = __tpm_tis_recv(chip, buf, count); > + 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; > @@ -375,7 +393,7 @@ 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; > } > } > > @@ -384,13 +402,13 @@ 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; > } > @@ -398,14 +416,10 @@ 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) > @@ -434,13 +448,17 @@ 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) > + 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..6cc6b76 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 { > -- > 2.7.4 > Just based on the explanation this looks like a bunch of unconsidered changes. You have explain yourself better. /Jarkko
