[PATCH RFC,v2] tpm_crb: request and relinquish locality 0

[Jarkko Sakkinen]

Added two new callbacks to struct tpm_class_ops:

- request_locality
- relinquish_locality

These are called before sending and receiving data from the TPM.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
This not yet v2 of this patch. I'm checking that this is what needs to be done
for tpm_tis_core before I go through testing etc. Thank you.
 drivers/char/tpm/tpm-interface.c |  9 +++++++++
 drivers/char/tpm/tpm_crb.c       | 41 +++++++++++++++++++++++++++++++++++++++-
 drivers/char/tpm/tpm_tis_core.c  | 10 +++-------
 include/linux/tpm.h              |  3 ++-
 4 files changed, 54 insertions(+), 9 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index e38c792..036843e 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);
+		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);
+
 	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 */
+				 TPM2_TIMEOUT_C)) {
+		dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static void crb_relinquish_locality(struct tpm_chip *chip, int loc, bool force)
+{
+	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+	if (!priv->regs_h)
+		return;
+
+	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
+}
+
 static u8 crb_status(struct tpm_chip *chip)
 {
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
@@ -198,7 +236,6 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 
 	memcpy_fromio(buf, priv->rsp, 6);
 	expected = be32_to_cpup((__be32 *) &buf[2]);
-
 	if (expected > count)
 		return -EIO;
 
@@ -279,6 +316,8 @@ static const struct tpm_class_ops tpm_crb = {
 	.send = crb_send,
 	.cancel = crb_cancel,
 	.req_canceled = crb_req_canceled,
+	.request_locality = crb_request_locality,
+	.relinquish_locality = crb_relinquish_locality,
 	.req_complete_mask = CRB_DRV_STS_COMPLETE,
 	.req_complete_val = CRB_DRV_STS_COMPLETE,
 };
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index fc0e9a2..505e9c5 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -73,7 +73,7 @@ static int check_locality(struct tpm_chip *chip, int l)
 	return -1;
 }
 
-static void release_locality(struct tpm_chip *chip, int l, int force)
+static void release_locality(struct tpm_chip *chip, int l, bool force)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int rc;
@@ -252,7 +252,6 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 
 out:
 	tpm_tis_ready(chip);
-	release_locality(chip, priv->locality, 0);
 	return size;
 }
 
@@ -268,9 +267,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 	size_t count = 0;
 	bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
 
-	if (request_locality(chip, 0) < 0)
-		return -EBUSY;
-
 	status = tpm_tis_status(chip);
 	if ((status & TPM_STS_COMMAND_READY) == 0) {
 		tpm_tis_ready(chip);
@@ -329,7 +325,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 
 out_err:
 	tpm_tis_ready(chip);
-	release_locality(chip, priv->locality, 0);
 	return rc;
 }
 
@@ -390,7 +385,6 @@ static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
 	return len;
 out_err:
 	tpm_tis_ready(chip);
-	release_locality(chip, priv->locality, 0);
 	return rc;
 }
 
@@ -681,6 +675,8 @@ static const struct tpm_class_ops tpm_tis = {
 	.send = tpm_tis_send,
 	.cancel = tpm_tis_ready,
 	.update_timeouts = tpm_tis_update_timeouts,
+	.request_locality = request_locality,
+	.relinquish_locality = release_locality,
 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 	.req_canceled = tpm_tis_req_canceled,
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index da158f0..65e05f9 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -48,7 +48,8 @@ struct tpm_class_ops {
 	u8 (*status) (struct tpm_chip *chip);
 	bool (*update_timeouts)(struct tpm_chip *chip,
 				unsigned long *timeout_cap);
-
+	int (*request_locality)(struct tpm_chip *chip, int loc);
+	void (*relinquish_locality)(struct tpm_chip *chip, int loc, bool force);
 };
 
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
-- 
2.9.3