linux-kernel - Re: [PATCH v4 RESEND 2/2] tpm: do not suspend/resume if power stays on

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Date:   Mon, 3 Jul 2017 16:00:50 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Rob Herring <robh+dt@...nel.org>, Peter Huewe <peterhuewe@....de>,
        tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        Sonny Rao <sonnyrao@...omium.org>, groeck@...omium.org
Subject: Re: [PATCH v4 RESEND 2/2] tpm: do not suspend/resume if power stays
 on

On Tue, Jun 27, 2017 at 12:27:24PM +0200, Enric Balletbo i Serra wrote:
> 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@...omium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> Reviewed-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
> Changes since v3.
>   - Rebased on top of linux-next
>  Rob Herring
>   - Split DT binding from code patch as is preferred.
> Changes since v2:
>  Jarkko Sakkinen
>   - Add a new TPM_CHIP_FLAG_ALWAYS_POWERED flag instead of using a boolean variable.
>   - Remove a trailing newline.
> Changes since v1:
>  Jason Gunthorpe :
>   - Move the code to handle suspend/resume in the common chip code.
> 
>  drivers/char/tpm/tpm-interface.c | 3 +++
>  drivers/char/tpm/tpm.h           | 1 +
>  drivers/char/tpm/tpm_of.c        | 3 +++
>  3 files changed, 7 insertions(+)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index be54159..34ec7ce 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -1099,6 +1099,9 @@ int tpm_pm_suspend(struct device *dev)
>  	if (chip == NULL)
>  		return -ENODEV;
>  
> +	if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
> +		return 0;
> +
>  	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
>  		tpm2_shutdown(chip, TPM2_SU_STATE);
>  		return 0;
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index af05c14..b44d39c 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -170,6 +170,7 @@ enum tpm_chip_flags {
>  	TPM_CHIP_FLAG_IRQ		= BIT(2),
>  	TPM_CHIP_FLAG_VIRTUAL		= BIT(3),
>  	TPM_CHIP_FLAG_HAVE_TIMEOUTS	= BIT(4),
> +	TPM_CHIP_FLAG_ALWAYS_POWERED	= BIT(5),
>  };
>  
>  struct tpm_bios_log {
> diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
> index de57d4a..aadb7f4 100644
> --- a/drivers/char/tpm/tpm_of.c
> +++ b/drivers/char/tpm/tpm_of.c
> @@ -36,6 +36,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
>  	else
>  		return -ENODEV;
>  
> +	if (of_property_read_bool(np, "powered-while-suspended"))
> +		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
> +
>  	sizep = of_get_property(np, "linux,sml-size", NULL);
>  	basep = of_get_property(np, "linux,sml-base", NULL);
>  	if (sizep == NULL && basep == NULL)
> -- 
> 2.9.3

Applied.

/Jarkko