[PATCH] tpm_crb: request and relinquish locality 0

From: Jarkko Sakkinen
Date: Fri Mar 10 2017 - 18:58:31 EST


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>
---
drivers/char/tpm/tpm-interface.c | 9 +++++++++
drivers/char/tpm/tpm_crb.c | 41 +++++++++++++++++++++++++++++++++++++++-
include/linux/tpm.h | 3 ++-
3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index bd2128e..ae6aafa 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -369,6 +369,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
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 = chip->ops->send(chip, (u8 *) buf, count);
if (rc < 0) {
dev_err(&chip->dev,
@@ -410,6 +416,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
dev_err(&chip->dev,
"tpm_transmit: tpm_recv: error %zd\n", rc);
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..89dc8a176 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)
+{
+ 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)
+{
+ 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/include/linux/tpm.h b/include/linux/tpm.h
index da158f0..0ac6ea6 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);
+ void (*relinquish_locality)(struct tpm_chip *chip);
};

#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
--
2.9.3