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    SubjectRE: [tpmdd-devel] [PATCH v2 3/3] tpm_crb: request and relinquish locality 0
    Date
    > 
    > CC linux-security-module
    >
    > On Sat, Dec 03, 2016 at 07:52:13PM +0200, Jarkko Sakkinen wrote:
    > > Request and relinquish locality for the driver use in order to be a
    > > better citizen in a multi locality environment like TXT. The locality
    > > is requested and relinquished as part of going into and waking up from
    > > idle.
    >
    This has nothing to do with power management, please note, that this is run via runtime_pm handlers,
    which can be disabled via sysfs and actually on server platforms runtime pm is not relevant,
    while you cannot disable locality acquire/relinquish flow.

    NACK
    > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    > > ---
    > > drivers/char/tpm/tpm_crb.c | 36 ++++++++++++++++++++++++------------
    > > 1 file changed, 24 insertions(+), 12 deletions(-)
    > >
    > > diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
    > > index f986d02..f6e0beb 100644
    > > --- a/drivers/char/tpm/tpm_crb.c
    > > +++ b/drivers/char/tpm/tpm_crb.c
    > > @@ -34,6 +34,15 @@ enum crb_defaults {
    > > CRB_ACPI_START_INDEX = 1,
    > > };
    > >
    > > +enum crb_loc_ctrl {
    > > + CRB_LOC_CTRL_REQUEST_ACCESS = BIT(0),
    > > + CRB_LOC_CTRL_RELINQUISH = BIT(1),
    > > +};
    > > +
    > > +enum crb_loc_state {
    > > + CRB_LOC_STATE_LOC_ASSIGNED = BIT(1),
    > > +};
    > > +
    > > enum crb_ctrl_req {
    > > CRB_CTRL_REQ_CMD_READY = BIT(0),
    > > CRB_CTRL_REQ_GO_IDLE = BIT(1),
    > > @@ -101,12 +110,8 @@ struct crb_priv {
    > > * @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.
    > > + * Put device to the idle state and relinquish locality. The function
    > > + does
    > > + * nothing for devices with the ACPI-start method.
    > > *
    > > * Return: 0 always
    > > */
    > > @@ -115,6 +120,7 @@ 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_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
    This is misleading this has nothing to do with go idle, what is the
    > > iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
    > > /* we don't really care when this settles */
    > >
    > > @@ -146,11 +152,8 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg,
    > u32 mask, u32 value,
    > > * @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
    > > + * Try to wake up the device and request locality. The function does
    > > + nothing
    > > + * for devices with the ACPI-start method.
    > > *
    > > * Return: 0 on success -ETIME on timeout;
    > > */
    > > @@ -165,7 +168,16 @@ static int __maybe_unused crb_cmd_ready(struct
    > device *dev,
    > > CRB_CTRL_REQ_CMD_READY /* mask */,
    > > 0, /* value */
    > > TPM2_TIMEOUT_C)) {
    > > - dev_warn(dev, "cmdReady timed out\n");
    > > + dev_warn(dev, "TPM_CRB_CTRL_REQ_x.cmdReady timed
    > out\n");
    We are always in locality 0 here, right?

    > > + return -ETIME;
    > > + }
    > > +
    > > + iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h-
    > >loc_ctrl);
    > > + if (!crb_wait_for_reg_32(&priv->regs_h->loc_state,
    > > + CRB_LOC_STATE_LOC_ASSIGNED, /* mask */
    > > + CRB_LOC_STATE_LOC_ASSIGNED, /* value */
    > > + TPM2_TIMEOUT_C)) {
    > > + dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed
    > out\n");


    > > return -ETIME;
    > > }


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