On Thu, Sep 08, 2016 at 02:11:15PM +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 07, 2016 at 02:32:31PM +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.
> >
> > 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));
>
> What's the problem of using wait_for_tpm_stat like:
>
> http://git.infradead.org/users/jjs/linux-tpmdd.git/commitdiff/7a1172b5b3cb38083ae931309db216db3c528efe
I'm proponent for my version since it's less intrusive change and adds
less ad-hoc code to the CRB driver.
Would you mind if I would construct v3 with two patches from this patch
set and my version with some tweaks from your code that are needed for
the workaround?
/Jarkko
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