| Message ID | 1473924458-29062-1-git-send-email-tomas.winkler@intel.com |
|---|---|
| State | New |
| Headers | show |
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.sakkinen@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.winkler@intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@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 > ------------------------------------------------------------------------------
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)
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> 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.winkler@intel.com> --- 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(+)