From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH 1/3] tpm/tpm_crb: implement tpm crb idle state Date: Thu, 8 Sep 2016 14:11:15 +0300 Message-ID: <20160908111115.GD4712@intel.com> References: <1473247953-24617-1-git-send-email-tomas.winkler@intel.com> <1473247953-24617-2-git-send-email-tomas.winkler@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1473247953-24617-2-git-send-email-tomas.winkler-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Tomas Winkler Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net 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 oringal patch > 'tpm_crb: implement power tpm crb power management' > > Signed-off-by: Tomas Winkler > --- > 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 /Jarkko ------------------------------------------------------------------------------