[tpmdd-devel,v3] tpm: Apply a sane minimum adapterlimit value for retransmission.

Message ID 20170522092011.8937-1-enric.balletbo@collabora.com
State New
Headers show

Commit Message

Enric Balletbo i Serra May 22, 2017, 9:20 a.m.
From: Bryan Freed <bfreed@chromium.org>

When the I2C Infineon part is attached to an I2C adapter that imposes
a size limitation, large requests will fail with -EOPNOTSUPP. Retry
them with a sane minimum size without re-issuing the 0x05 command
as this appears to occasionally put the TPM in a bad state.

Signed-off-by: Bryan Freed <bfreed@chromium.org>
[rework the patch to adapt to the feedback received]
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
The purpose of this resend is only a reminder for if this can be accepted
for the next merge window as I missed last merge. Thanks.

 drivers/char/tpm/tpm_i2c_infineon.c | 76 +++++++++++++++++++++++++++----------
 1 file changed, 56 insertions(+), 20 deletions(-)

Comments

Jarkko Sakkinen May 24, 2017, 7:10 p.m. | #1
On Mon, May 22, 2017 at 11:20:11AM +0200, Enric Balletbo i Serra wrote:
> From: Bryan Freed <bfreed@chromium.org>
> 
> When the I2C Infineon part is attached to an I2C adapter that imposes
> a size limitation, large requests will fail with -EOPNOTSUPP. Retry
> them with a sane minimum size without re-issuing the 0x05 command
> as this appears to occasionally put the TPM in a bad state.
> 
> Signed-off-by: Bryan Freed <bfreed@chromium.org>
> [rework the patch to adapt to the feedback received]
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Acked-by: Andrew Lunn <andrew@lunn.ch>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Applied and should be available also in linux-next very soon.

/Jarkko

> ---
> The purpose of this resend is only a reminder for if this can be accepted
> for the next merge window as I missed last merge. Thanks.
> 
>  drivers/char/tpm/tpm_i2c_infineon.c | 76 +++++++++++++++++++++++++++----------
>  1 file changed, 56 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
> index dc47fa2..79d6bbb 100644
> --- a/drivers/char/tpm/tpm_i2c_infineon.c
> +++ b/drivers/char/tpm/tpm_i2c_infineon.c
> @@ -70,6 +70,7 @@ struct tpm_inf_dev {
>  	u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
>  	struct tpm_chip *chip;
>  	enum i2c_chip_type chip_type;
> +	unsigned int adapterlimit;
>  };
>  
>  static struct tpm_inf_dev tpm_dev;
> @@ -111,6 +112,7 @@ static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
>  
>  	int rc = 0;
>  	int count;
> +	unsigned int msglen = len;
>  
>  	/* Lock the adapter for the duration of the whole sequence. */
>  	if (!tpm_dev.client->adapter->algo->master_xfer)
> @@ -131,27 +133,61 @@ static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
>  			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
>  		}
>  	} else {
> -		/* slb9635 protocol should work in all cases */
> -		for (count = 0; count < MAX_COUNT; count++) {
> -			rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
> -			if (rc > 0)
> -				break;	/* break here to skip sleep */
> -
> -			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
> -		}
> -
> -		if (rc <= 0)
> -			goto out;
> -
> -		/* After the TPM has successfully received the register address
> -		 * it needs some time, thus we're sleeping here again, before
> -		 * retrieving the data
> +		/* Expect to send one command message and one data message, but
> +		 * support looping over each or both if necessary.
>  		 */
> -		for (count = 0; count < MAX_COUNT; count++) {
> -			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
> -			rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
> -			if (rc > 0)
> -				break;
> +		while (len > 0) {
> +			/* slb9635 protocol should work in all cases */
> +			for (count = 0; count < MAX_COUNT; count++) {
> +				rc = __i2c_transfer(tpm_dev.client->adapter,
> +						    &msg1, 1);
> +				if (rc > 0)
> +					break;	/* break here to skip sleep */
> +
> +				usleep_range(SLEEP_DURATION_LOW,
> +					     SLEEP_DURATION_HI);
> +			}
> +
> +			if (rc <= 0)
> +				goto out;
> +
> +			/* After the TPM has successfully received the register
> +			 * address it needs some time, thus we're sleeping here
> +			 * again, before retrieving the data
> +			 */
> +			for (count = 0; count < MAX_COUNT; count++) {
> +				if (tpm_dev.adapterlimit) {
> +					msglen = min_t(unsigned int,
> +						       tpm_dev.adapterlimit,
> +						       len);
> +					msg2.len = msglen;
> +				}
> +				usleep_range(SLEEP_DURATION_LOW,
> +					     SLEEP_DURATION_HI);
> +				rc = __i2c_transfer(tpm_dev.client->adapter,
> +						    &msg2, 1);
> +				if (rc > 0) {
> +					/* Since len is unsigned, make doubly
> +					 * sure we do not underflow it.
> +					 */
> +					if (msglen > len)
> +						len = 0;
> +					else
> +						len -= msglen;
> +					msg2.buf += msglen;
> +					break;
> +				}
> +				/* If the I2C adapter rejected the request (e.g
> +				 * when the quirk read_max_len < len) fall back
> +				 * to a sane minimum value and try again.
> +				 */
> +				if (rc == -EOPNOTSUPP)
> +					tpm_dev.adapterlimit =
> +							I2C_SMBUS_BLOCK_MAX;
> +			}
> +
> +			if (rc <= 0)
> +				goto out;
>  		}
>  	}
>  
> -- 
> 2.9.3
> 

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot

Patch

diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
index dc47fa2..79d6bbb 100644
--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -70,6 +70,7 @@  struct tpm_inf_dev {
 	u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
 	struct tpm_chip *chip;
 	enum i2c_chip_type chip_type;
+	unsigned int adapterlimit;
 };
 
 static struct tpm_inf_dev tpm_dev;
@@ -111,6 +112,7 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 
 	int rc = 0;
 	int count;
+	unsigned int msglen = len;
 
 	/* Lock the adapter for the duration of the whole sequence. */
 	if (!tpm_dev.client->adapter->algo->master_xfer)
@@ -131,27 +133,61 @@  static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
 			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 		}
 	} else {
-		/* slb9635 protocol should work in all cases */
-		for (count = 0; count < MAX_COUNT; count++) {
-			rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
-			if (rc > 0)
-				break;	/* break here to skip sleep */
-
-			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
-		}
-
-		if (rc <= 0)
-			goto out;
-
-		/* After the TPM has successfully received the register address
-		 * it needs some time, thus we're sleeping here again, before
-		 * retrieving the data
+		/* Expect to send one command message and one data message, but
+		 * support looping over each or both if necessary.
 		 */
-		for (count = 0; count < MAX_COUNT; count++) {
-			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
-			rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
-			if (rc > 0)
-				break;
+		while (len > 0) {
+			/* slb9635 protocol should work in all cases */
+			for (count = 0; count < MAX_COUNT; count++) {
+				rc = __i2c_transfer(tpm_dev.client->adapter,
+						    &msg1, 1);
+				if (rc > 0)
+					break;	/* break here to skip sleep */
+
+				usleep_range(SLEEP_DURATION_LOW,
+					     SLEEP_DURATION_HI);
+			}
+
+			if (rc <= 0)
+				goto out;
+
+			/* After the TPM has successfully received the register
+			 * address it needs some time, thus we're sleeping here
+			 * again, before retrieving the data
+			 */
+			for (count = 0; count < MAX_COUNT; count++) {
+				if (tpm_dev.adapterlimit) {
+					msglen = min_t(unsigned int,
+						       tpm_dev.adapterlimit,
+						       len);
+					msg2.len = msglen;
+				}
+				usleep_range(SLEEP_DURATION_LOW,
+					     SLEEP_DURATION_HI);
+				rc = __i2c_transfer(tpm_dev.client->adapter,
+						    &msg2, 1);
+				if (rc > 0) {
+					/* Since len is unsigned, make doubly
+					 * sure we do not underflow it.
+					 */
+					if (msglen > len)
+						len = 0;
+					else
+						len -= msglen;
+					msg2.buf += msglen;
+					break;
+				}
+				/* If the I2C adapter rejected the request (e.g
+				 * when the quirk read_max_len < len) fall back
+				 * to a sane minimum value and try again.
+				 */
+				if (rc == -EOPNOTSUPP)
+					tpm_dev.adapterlimit =
+							I2C_SMBUS_BLOCK_MAX;
+			}
+
+			if (rc <= 0)
+				goto out;
 		}
 	}