Am 5. April 2017 11:03:27 MESZ schrieb Jarkko Sakkinen
<jarkko.sakki...@linux.intel.com>:
>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?
>
Not yet, I'll put it on my list to test.
Hopefully by next tuesday.
Peter
>/Jarkko
--
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