[PATCH v2] tpm_crb: request and relinquish locality 0

On Sun, Mar 12, 2017 at 12:47:58PM -0700, Jerry Snitselaar wrote:

Jarkko Sakkinen @ 2017-03-11 13:02 GMT:

quoted

Added two new callbacks to struct tpm_class_ops:

- request_locality
- relinquish_locality

These are called before sending and receiving data from the TPM.  We
update also tpm_tis_core to use these callbacks. Small modification to
request_locality() is done so that it returns -EBUSY instead of locality
number when check_locality() fails.

Signed-off-by: Jarkko Sakkinen <redacted>
---
 drivers/char/tpm/tpm-interface.c |  9 +++++++++
 drivers/char/tpm/tpm_crb.c       | 41 +++++++++++++++++++++++++++++++++++++++-
 drivers/char/tpm/tpm_tis_core.c  | 12 ++++--------
 include/linux/tpm.h              |  3 ++-
 4 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index e38c792..9c56581 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c

@@ -407,6 +407,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	if (chip->dev.parent)
 		pm_runtime_get_sync(chip->dev.parent);
 
+	if (chip->ops->request_locality)  {
+		rc = chip->ops->request_locality(chip, 0);
+		if (rc)
+			goto out;
+	}
+
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
 		goto out;

@@ -466,6 +472,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
 
 out:
+	if (chip->ops->relinquish_locality)
+		chip->ops->relinquish_locality(chip, 0, false);
+
 	if (chip->dev.parent)
 		pm_runtime_put_sync(chip->dev.parent);
 

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 3245618..15b22a0 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c

@@ -34,6 +34,15 @@ enum crb_defaults {
 	CRB_ACPI_START_INDEX = 1,
 };
 
+enum crb_loc_ctrl {
+	CRB_LOC_CTRL_REQUEST_ACCESS	= BIT(0),
+	CRB_LOC_CTRL_RELINQUISH		= BIT(1),
+};
+
+enum crb_loc_state {
+	CRB_LOC_STATE_LOC_ASSIGNED	= BIT(1),
+};
+
 enum crb_ctrl_req {
 	CRB_CTRL_REQ_CMD_READY	= BIT(0),
 	CRB_CTRL_REQ_GO_IDLE	= BIT(1),

@@ -172,6 +181,35 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
 	return 0;
 }
 
+static int crb_request_locality(struct tpm_chip *chip, int loc)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+	if (!priv->regs_h)
+		return 0;
+
+	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
+	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state,
+				 CRB_LOC_STATE_LOC_ASSIGNED, /* mask */
+				 CRB_LOC_STATE_LOC_ASSIGNED, /* value */

Should this mask and check bit 7 as well (tpmRegValidSts)? The
table with the definition in the PTP spec says it indicates whether
all other bits contain valid values, but the text above it doesn't
discuss the locAssigned and activeLocality bits with respect to
tpmRegValidSts, so not completely clear.

You are probably right. There's also regression with the resource
manager (in this patch not in RM) that I'll fix. Thaks for reporting
this.

/Jarkko
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