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Commit e17acbbb authored by Winkler, Tomas's avatar Winkler, Tomas Committed by Jarkko Sakkinen
Browse files

tpm/tpm_crb: implement tpm crb idle state 



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: default avatarTomas Winkler <tomas.winkler@intel.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent ebfd7532

drivers/char/tpm/tpm_crb.c

+69 −0
Original line number Diff line number Diff line
@@ -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)