diff options
Diffstat (limited to 'src/drivers')
| -rw-r--r-- | src/drivers/pc80/tpm/Kconfig | 9 | ||||
| -rw-r--r-- | src/drivers/pc80/tpm/tis.c | 8 |
2 files changed, 17 insertions, 0 deletions
diff --git a/src/drivers/pc80/tpm/Kconfig b/src/drivers/pc80/tpm/Kconfig index 3bd9083802..879b4a2341 100644 --- a/src/drivers/pc80/tpm/Kconfig +++ b/src/drivers/pc80/tpm/Kconfig @@ -46,3 +46,12 @@ config TPM_DEACTIVATE depends on LPC_TPM help Deactivate TPM by issuing deactivate command. + +config TPM_RDRESP_NEED_DELAY + bool "Enable Delay Workaround for TPM" + default n + depends on LPC_TPM + help + Certain TPMs seem to need some delay when reading response + to work around a race-condition-related issue, possibly + caused by ill-programmed TPM firmware. diff --git a/src/drivers/pc80/tpm/tis.c b/src/drivers/pc80/tpm/tis.c index 9802654ee1..714b7e5ed0 100644 --- a/src/drivers/pc80/tpm/tis.c +++ b/src/drivers/pc80/tpm/tis.c @@ -595,6 +595,14 @@ static u32 tis_readresponse(u8 *buffer, size_t *len) if (offset == expected_count) break; /* We got all we need */ + /* + * Certain TPMs seem to need some delay between tis_wait_valid() + * and tis_has_valid_data(), or some race-condition-related + * issue will occur. + */ + if (IS_ENABLED(CONFIG_TPM_RDRESP_NEED_DELAY)) + udelay(10); + } while (tis_has_valid_data(locality)); /* * Make sure we indeed read all there was. */ |