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SubjectRe: [PATCH v2 1/2] tpm: do not suspend/resume if power stays on
On Wed, May 30, 2018 at 11:44:39PM +0300, Jarkko Sakkinen wrote:
> From: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>
> commit b5d0ebc99bf5d0801a5ecbe958caa3d68b8eaee8 upstream
>
> The suspend/resume behavior of the TPM can be controlled by setting
> "powered-while-suspended" in the DTS. This is useful for the cases
> when hardware does not power-off the TPM.
>
> Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: James Morris <james.l.morris@oracle.com>
> ---
> drivers/char/tpm/tpm-chip.c | 12 ++++++++++++
> drivers/char/tpm/tpm-interface.c | 3 +++
> drivers/char/tpm/tpm.h | 1 +
> 3 files changed, 16 insertions(+)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index a0d9ac6b6cc9..a8d7220f613c 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -324,8 +324,20 @@ static void tpm1_chip_unregister(struct tpm_chip *chip)
> */
> int tpm_chip_register(struct tpm_chip *chip)
> {
> +#ifdef CONFIG_TCG_IBMVTPM
> + struct device_node *np;
> +#endif
> int rc;
>
> +#ifdef CONFIG_TCG_IBMVTPM
> + np = of_find_node_by_name(NULL, "vtpm");
> + if (!np)
> + return -ENODEV;
> + if (of_property_read_bool(np, "powered-while-suspended"))
> + chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
> + of_node_put(np);
> +#endif

I'll have to revise this as more config flag should be CONFIG_OF
and property should be conditionally read if the node is found.
Then it can be relocated without interference.

/Jarkko

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