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tpm/tpm_crb: implement tpm crb idle state

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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>
This commit is contained in:
Winkler, Tomas 2016-09-15 10:27:38 +03:00 committed by Jarkko Sakkinen
parent ebfd7532e9
commit e17acbbb69
1 changed files with 69 additions and 0 deletions
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69
drivers/char/tpm/tpm_crb.c
View file

@ -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)