Messages in this thread | | | From | "Winkler, Tomas" <> | Subject | RE: [PATCH v3 1/4] tpm/tpm_crb: implement tpm crb idle state | Date | Thu, 15 Sep 2016 06:28:27 +0000 |
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> Subject: Re: [PATCH v3 1/4] tpm/tpm_crb: implement tpm crb idle state > > On Mon, Sep 12, 2016 at 04:04:18PM +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.sakkinen@linux.intel.com> oringal > > patch: > > 'tpm_crb: implement power tpm crb power management' > > > > > > Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> > > --- > > V2: do not export the functions via tpm ops > > V3: fix lower case corruption; adjust function documentation > > > > 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)); > > Since this is HW specific this is right thing to do and not abuse > wait_for_tpm_stat. However, this should be documented to the commit > message. I will respin just this patch and not the whole series, as the fix is only in the commit message. Tomas
> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > /Jarkko
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