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author | Winkler, Tomas <tomas.winkler@intel.com> | 2016-09-15 07:27:38 (GMT) |
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committer | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2016-09-16 12:47:36 (GMT) |
commit | e17acbbb69d30836a8c12e2c09bbefab8656693e (patch) | |
tree | ec99a60f272655fbeb33d08eb6fd81183d819ede /drivers/char/tpm | |
parent | ebfd7532e985818a327906e011f3e43c8ddfdd74 (diff) | |
download | linux-e17acbbb69d30836a8c12e2c09bbefab8656693e.tar.xz |
tpm/tpm_crb: implement tpm crb idle state
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.
Based on Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
original patch:
'tpm_crb: implement power tpm crb power management'
To keep the implementation local to the hw we don't use wait_for_tpm_stat
for polling the TPM_CRB_CTRL_REQ.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm')
-rw-r--r-- | drivers/char/tpm/tpm_crb.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index a7c870a..466d12b 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -83,6 +83,75 @@ struct crb_priv { u32 cmd_size; }; +/** + * crb_go_idle - request tpm crb device to go the idle state + * + * @dev: crb device + * @priv: crb private data + * + * 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. + * + * The function does nothing for devices with ACPI-start method. + * + * Return: 0 always + */ +static int __maybe_unused 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; +} + +/** + * crb_cmd_ready - request tpm crb device to enter ready state + * + * @dev: crb device + * @priv: crb private data + * + * 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 + * + * Return: 0 on success -ETIME on timeout; + */ +static int __maybe_unused 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(50, 100); + } 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 SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume); static u8 crb_status(struct tpm_chip *chip) |