On Mon, Aug 25, 2025 at 03:59:43PM -0500, Stuart Yoder wrote:
> According to the CRB over FF-A specification [1], a TPM that implements
> the ABI must comply with the TCG PTP specification. This requires support
> for the Idle and Ready states.
>
> This patch implements CRB control area requests for goIdle and
> cmdReady on FF-A based TPMs.
>
> The FF-A message used to notify the TPM of CRB updates includes a
> locality parameter, which provides a hint to the TPM about which
> locality modified the CRB. This patch adds a locality parameter
> to __crb_go_idle() and __crb_cmd_ready() to support this.
>
> [1] https://developer.arm.com/documentation/den0138/latest/
>
> Signed-off-by: Stuart Yoder <stuart.yo...@arm.com>
Perhaps a dummy question but is this "QEMU testable"? I know how
to bind swtpm to QEMU and make it appear as CRB device on x86-64.
I don't see much testing happening with these ARM CRB patches,
and if that works in the first palce I could probably add
a new board target to my BR2_EXTERNAL [1].
I can of course do "negative testing' i.e. that these don't
break x86 ;-)
> ---
> drivers/char/tpm/tpm_crb.c | 29 ++++++++++++++++++++---------
> 1 file changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 876edf2705abb..a18bae0a53717 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -133,8 +133,7 @@ static inline bool tpm_crb_has_idle(u32 start_method)
> {
> return !(start_method == ACPI_TPM2_START_METHOD ||
> start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD ||
> - start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC ||
> - start_method == ACPI_TPM2_CRB_WITH_ARM_FFA);
> + start_method == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
> }
>
> static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> @@ -191,7 +190,7 @@ static int crb_try_pluton_doorbell(struct crb_priv *priv,
> bool wait_for_complete
> *
> * Return: 0 always
> */
> -static int __crb_go_idle(struct device *dev, struct crb_priv *priv)
> +static int __crb_go_idle(struct device *dev, struct crb_priv *priv, int loc)
> {
> int rc;
>
> @@ -200,6 +199,12 @@ static int __crb_go_idle(struct device *dev, struct
> crb_priv *priv)
>
> iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
>
> + if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
> + rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, loc);
> + if (rc)
> + return rc;
> + }
> +
> rc = crb_try_pluton_doorbell(priv, true);
> if (rc)
> return rc;
> @@ -220,7 +225,7 @@ static int crb_go_idle(struct tpm_chip *chip)
> struct device *dev = &chip->dev;
> struct crb_priv *priv = dev_get_drvdata(dev);
>
> - return __crb_go_idle(dev, priv);
> + return __crb_go_idle(dev, priv, chip->locality);
> }
>
> /**
> @@ -238,7 +243,7 @@ static int crb_go_idle(struct tpm_chip *chip)
> *
> * Return: 0 on success -ETIME on timeout;
> */
> -static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv)
> +static int __crb_cmd_ready(struct device *dev, struct crb_priv *priv, int
> loc)
> {
> int rc;
>
> @@ -247,6 +252,12 @@ static int __crb_cmd_ready(struct device *dev, struct
> crb_priv *priv)
>
> iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
>
> + if (priv->sm == ACPI_TPM2_CRB_WITH_ARM_FFA) {
> + rc = tpm_crb_ffa_start(CRB_FFA_START_TYPE_COMMAND, loc);
> + if (rc)
> + return rc;
> + }
> +
> rc = crb_try_pluton_doorbell(priv, true);
> if (rc)
> return rc;
> @@ -267,7 +278,7 @@ static int crb_cmd_ready(struct tpm_chip *chip)
> struct device *dev = &chip->dev;
> struct crb_priv *priv = dev_get_drvdata(dev);
>
> - return __crb_cmd_ready(dev, priv);
> + return __crb_cmd_ready(dev, priv, chip->locality);
> }
>
> static int __crb_request_locality(struct device *dev,
> @@ -444,7 +455,7 @@ static int crb_send(struct tpm_chip *chip, u8 *buf,
> size_t len)
>
> /* Seems to be necessary for every command */
> if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON)
> - __crb_cmd_ready(&chip->dev, priv);
> + __crb_cmd_ready(&chip->dev, priv, chip->locality);
>
> memcpy_toio(priv->cmd, buf, len);
>
> @@ -672,7 +683,7 @@ static int crb_map_io(struct acpi_device *device, struct
> crb_priv *priv,
> * PTT HW bug w/a: wake up the device to access
> * possibly not retained registers.
> */
> - ret = __crb_cmd_ready(dev, priv);
> + ret = __crb_cmd_ready(dev, priv, 0);
> if (ret)
> goto out_relinquish_locality;
>
> @@ -744,7 +755,7 @@ static int crb_map_io(struct acpi_device *device, struct
> crb_priv *priv,
> if (!ret)
> priv->cmd_size = cmd_size;
>
> - __crb_go_idle(dev, priv);
> + __crb_go_idle(dev, priv, 0);
>
> out_relinquish_locality:
>
> --
> 2.34.1
>
>
[1] https://codeberg.org/jarkko/linux-tpmdd-test
BR, Jarkko
