The register TPM_CRB_CTRL_REQ_x contains bits goIdle and cmdReady for
SW to indicate that the device can enter or should exit the idle state.
The legacy ACPI-start (SMI + DMA) based devices do not support these
bits and the idle state management is not exposed to the host SW.
Thus, this functionality only is enabled only for a CRB start (MMIO)
based devices.
We introduce two new callbacks for command ready and go idle for TPM CRB
device which are called across TPM transactions.
Based on Jarkko Sakkinen <jarkko.sakki...@linux.intel.com> oringal patch
'tpm_crb: implement power tpm crb power management'
Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
---
drivers/char/tpm/tpm-interface.c | 21 +++++++++++
drivers/char/tpm/tpm_crb.c | 77 ++++++++++++++++++++++++++++++++++++++++
include/linux/tpm.h | 3 +-
3 files changed, 100 insertions(+), 1 deletion(-)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index fd863ff30f79..c78dca5ce7a6 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -327,6 +327,20 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip
*chip,
}
EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
+static inline int tpm_go_idle(struct tpm_chip *chip)
+{
+ if (!chip->ops->idle)
+ return 0;
+ return chip->ops->idle(chip);
+}
+
+static inline int tpm_cmd_ready(struct tpm_chip *chip)
+{
+ if (!chip->ops->ready)
+ return 0;
+ return chip->ops->ready(chip);
+}
+
/*
* Internal kernel interface to transmit TPM commands
*/
@@ -353,6 +367,10 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf,
size_t bufsiz,
if (!(flags & TPM_TRANSMIT_UNLOCKED))
mutex_lock(&chip->tpm_mutex);
+ rc = tpm_cmd_ready(chip);
+ if (rc)
+ goto out;
+
rc = chip->ops->send(chip, (u8 *) buf, count);
if (rc < 0) {
dev_err(&chip->dev,
@@ -394,8 +412,11 @@ out_recv:
dev_err(&chip->dev,
"tpm_transmit: tpm_recv: error %zd\n", rc);
out:
+ tpm_go_idle(chip);
+
if (!(flags & TPM_TRANSMIT_UNLOCKED))
mutex_unlock(&chip->tpm_mutex);
+
return rc;
}
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 82a3ccd52a3a..98a7fdfe9936 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -83,6 +83,81 @@ struct crb_priv {
u8 __iomem *rsp;
};
+/**
+ * __crb_go_idle - write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
+ * The device should respond within TIMEOUT_C by clearing the bit.
+ * Anyhow, we do not wait here as a consequent CMD_READY request
+ * will be handled correctly even if idle was not completed.
+ *
+ * @dev: tpm device
+ * @priv: crb private context
+ *
+ * Return: 0 always
+ */
+static int __crb_go_idle(struct device *dev, struct crb_priv *priv)
+{
+ if (priv->flags & CRB_FL_ACPI_START)
+ return 0;
+ iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->cca->req);
+ /* we don't really care when this settles */
+
+ return 0;
+}
+
+static int crb_go_idle(struct tpm_chip *chip)
+{
+ struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+ return __crb_go_idle(&chip->dev, priv);
+}
+
+/**
+ * __crb_cmd_ready - write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
+ * and poll till the device acknowledge it by clearing the bit.
+ * The device should respond within TIMEOUT_C.
+ *
+ * The function does nothing for devices with ACPI-start method
+ *
+ * @dev: tpm device
+ * @priv: crb private context
+ *
+ * Return: 0 on success -ETIME on timeout;
+ */
+static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv)
+{
+ ktime_t stop, start;
+
+ if (priv->flags & CRB_FL_ACPI_START)
+ return 0;
+
+ iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->cca->req);
+
+ start = ktime_get();
+ stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
+ do {
+ if (!(ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY)) {
+ dev_dbg(dev, "cmdReady in %lld usecs\n",
+ ktime_to_us(ktime_sub(ktime_get(), start)));
+ return 0;
+ }
+ usleep_range(500, 1000);
+ } while (ktime_before(ktime_get(), stop));
+
+ if (ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY) {
+ dev_warn(dev, "cmdReady timed out\n");
+ return -ETIME;
+ }
+
+ return 0;
+}
+
+static int crb_cmd_ready(struct tpm_chip *chip)
+{
+ struct crb_priv *priv = dev_get_drvdata(&chip->dev);
+
+ return __crb_cmd_ready(&chip->dev, priv);
+}
+
static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
static u8 crb_status(struct tpm_chip *chip)
@@ -193,6 +268,8 @@ static const struct tpm_class_ops tpm_crb = {
.recv = crb_recv,
.send = crb_send,
.cancel = crb_cancel,
+ .ready = crb_cmd_ready,
+ .idle = crb_go_idle,
.req_canceled = crb_req_canceled,
.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 da158f06e0b2..1ed9ff6a5d48 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 (*idle)(struct tpm_chip *chip);
+ int (*ready)(struct tpm_chip *chip);
};
#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
--
2.7.4
------------------------------------------------------------------------------
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