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Subject[PATCH] tpm, tpm_crb: remove redundant CRB_FL_CRB_START flag
Date
Because all the existing hardware have HID MSFT0101 we end up always
setting CRB_FL_CRB_START flag as a workaround for 4th Gen Core CPUs.
Even if ACPI start is used, the driver will always issue also CRB start.

This commit makes the invocation of CRB start unconditional.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
drivers/char/tpm/tpm_crb.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 65040d7..5928ec8 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -72,7 +72,6 @@ enum crb_status {

enum crb_flags {
CRB_FL_ACPI_START = BIT(0),
- CRB_FL_CRB_START = BIT(1),
};

struct crb_priv {
@@ -226,8 +225,11 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
/* Make sure that cmd is populated before issuing start. */
wmb();

- if (priv->flags & CRB_FL_CRB_START)
- iowrite32(CRB_START_INVOKE, &priv->cca->start);
+
+ /* At least some of the 4th Gen Core CPUs that report only needing ACPI
+ * start require also CRB start so we always set it just in case.
+ */
+ iowrite32(CRB_START_INVOKE, &priv->cca->start);

if (priv->flags & CRB_FL_ACPI_START)
rc = crb_do_acpi_start(chip);
@@ -407,14 +409,6 @@ static int crb_acpi_add(struct acpi_device *device)
if (!priv)
return -ENOMEM;

- /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
- * report only ACPI start but in practice seems to require both
- * ACPI start and CRB start.
- */
- if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
- !strcmp(acpi_device_hid(device), "MSFT0101"))
- priv->flags |= CRB_FL_CRB_START;
-
if (sm == ACPI_TPM2_START_METHOD ||
sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
priv->flags |= CRB_FL_ACPI_START;
--
2.9.3
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