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
> 

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