Some TPMs fail to grant locality when requested immediately after being relinquished. In this case, the TPM_ACCESS_REQUEST_USE bit of the TPM_ACCESS register is cleared immediately without setting TPM_ACCESS_ACTIVE_LOCALITY.
This issue can be seen at boot since tpm_chip_start, called right after locality is relinquished, fails. This causes the probe to fail: tpm_tis MSFT0101:00: probe with driver tpm_tis failed with error -1 This occurs on some older Dell Latitudes and maybe others. To work around this, add a "settle" boolean param to tpm_tis. When this is enabled, a delay is added after locality is relinquished. Signed-off-by: Jim Broadus <[email protected]> --- Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ drivers/char/tpm/tpm_tis.c | 7 +++++++ drivers/char/tpm/tpm_tis_core.c | 3 +++ drivers/char/tpm/tpm_tis_core.h | 1 + 4 files changed, 18 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 4d0f545fb3ec..5b7111033fbb 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -7651,6 +7651,13 @@ Kernel parameters defined by Trusted Computing Group (TCG) see https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/ + tpm_tis.settle= [HW,TPM] + Format: <bool> + When enabled, this adds a delay after locality is + relinquished. Some TPMs will fail to grant locality if + requested immediately after being relinquished. This + causes the probe to fail. + tp_printk [FTRACE] Have the tracepoints sent to printk as well as the tracing ring buffer. This is useful for early boot up diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c index 9aa230a63616..8ac0ea78570e 100644 --- a/drivers/char/tpm/tpm_tis.c +++ b/drivers/char/tpm/tpm_tis.c @@ -101,6 +101,10 @@ module_param(force, bool, 0444); MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry"); #endif +static bool settle; +module_param(settle, bool, 0444); +MODULE_PARM_DESC(settle, "Add settle time after relinquish"); + #if defined(CONFIG_PNP) && defined(CONFIG_ACPI) static int has_hid(struct acpi_device *dev, const char *hid) { @@ -242,6 +246,9 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info) if (itpm || is_itpm(ACPI_COMPANION(dev))) set_bit(TPM_TIS_ITPM_WORKAROUND, &phy->priv.flags); + if (settle) + set_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &phy->priv.flags); + return tpm_tis_core_init(dev, &phy->priv, irq, &tpm_tcg, ACPI_HANDLE(dev)); } diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 21d79ad3b164..fbeee085098e 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -171,6 +171,9 @@ static int __tpm_tis_relinquish_locality(struct tpm_tis_data *priv, int l) { tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY); + if (test_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &priv->flags)) + tpm_msleep(TPM_TIMEOUT); + return 0; } diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index 6c3aa480396b..413cac5e0f31 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -90,6 +90,7 @@ enum tpm_tis_flags { TPM_TIS_DEFAULT_CANCELLATION = 2, TPM_TIS_IRQ_TESTED = 3, TPM_TIS_STATUS_VALID_RETRY = 4, + TPM_TIS_SETTLE_AFTER_RELINQUISH = 5, }; struct tpm_tis_data { -- 2.54.0
