tpm: tpm_tis: Add settle time for some TPMs

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, will fail. 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. For the Nuvoton TPM used in
these machines, add a delay after locality is relinquished.

Signed-off-by: Jim Broadus <jbroadus@gmail.com>
Link: https://lore.kernel.org/r/20260526232245.5409-3-jbroadus@gmail.com
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 3408b531d3b890053c7f43f54268cc1f0ec2881b..143ef160820e2d43b0624cdcf53c52993c3a221e 100644 (file)
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -178,6 +178,9 @@ 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;
 }
 
@@ -1173,6 +1176,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
        if (vendor_id == TPM_VID_IFX)
                set_bit(TPM_TIS_STATUS_VALID_RETRY, &priv->flags);
 
+       if (vendor_id == TPM_VID_WINBOND && device_id == 0x00FE)
+               set_bit(TPM_TIS_SETTLE_AFTER_RELINQUISH, &priv->flags);
+
        if (is_bsw()) {
                priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR,
                                        ILB_REMAP_SIZE);

diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index f2c77844062a83face086301436ab8a6934eafe5..aa6d78898ef31a6bba021122a402f9491756da76 100644 (file)
--- 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 {