On Tue, Mar 28, 2017 at 05:29:38PM +0200, Enric Balletbo i Serra wrote:
> From: Bryan Freed <bfr...@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 <bfr...@chromium.org>
> [rework the patch to adapt to the feedback received]
> Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
> ---
> This is a reworked version of the original patch based on the
> suggestion made by Wolfram Sang to simply fall back to a sane minimum
> when the maximum fails.
>
> Changes since v2:
> - Do not remove faster transfers when chip is SLB9645 (Peter Huewe)
> - Remember the adapterlimit length once it fails to not generate extra
> i2c core messages (suggested by Andrew Lunn)
> Changes since v1:
> - Check the correct return value (-EOPNOTSUPP instead of -EINVAL)
> - Fall back len to I2C_SMBUS_BLOCK_MAX if fails.
>
> 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 62ee44e..fdefcdb 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
>
Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
Peter, Andrew, anyone: Tested-by?
/Jarkko
