On Thu, Sep 15, 2016 at 10:27:38AM +0300, Tomas Winkler wrote:
> 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.sakki...@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.wink...@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
What about callback names? I've been thinking to name them simply as
'runtime_suspend' and 'runtime_resume'. I can do renaming.
/Jarkko
> ---
> V2: do not export the functions via tpm ops
> V3: fix lower case corruption; adjust function documentation
> V4: comment on wait_for_tpm_stat.
>
> drivers/char/tpm/tpm_crb.c | 69
> ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 6e9d1bca712f..b6923a8b3ff7 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)
> --
> 2.7.4
>
