linux-kernel - Re: [PATCH v3] char: tpm: cr50: Set TPM_FIRMWARE_POWER

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Date:   Sat, 11 Dec 2021 07:06:05 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Rob Barnes <robbarnes@...gle.com>, Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] char: tpm: cr50: Set TPM_FIRMWARE_POWER_MANAGED
 based on device property

On Mon, 2021-12-06 at 12:03 +0000, Rob Barnes wrote:
> Set TPM_FIRMWARE_POWER_MANAGED flag based on 'firmware-power-managed'
> ACPI DSD property. For the CR50 TPM, this flag defaults to true when
> the property is unset.
> 
> When this flag is set to false, the CR50 TPM driver will always send
> a shutdown command whenever the system suspends.
> 
> Signed-off-by: Rob Barnes <robbarnes@...gle.com>
> ---
>  drivers/char/tpm/tpm_tis_i2c_cr50.c | 16 +++++++++++++++-
>  drivers/char/tpm/tpm_tis_spi_cr50.c | 16 +++++++++++++++-
>  2 files changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> index c89278103703..f6c0affbb456 100644
> --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
> +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> @@ -628,6 +628,19 @@ static bool tpm_cr50_i2c_req_canceled(struct tpm_chip *chip, u8 status)
>  	return status == TPM_STS_COMMAND_READY;
>  }
>  
> +static bool tpm_cr50_i2c_is_firmware_power_managed(struct device *dev)
> +{
> +	u8 val;
> +	int ret;
> +
> +	/* This flag should default true when the device property is not present */
> +	ret = device_property_read_u8(dev, "firmware-power-managed", &val);
> +	if (ret)
> +		return true;
> +
> +	return val;
> +}
> +
>  static const struct tpm_class_ops cr50_i2c = {
>  	.flags = TPM_OPS_AUTO_STARTUP,
>  	.status = &tpm_cr50_i2c_tis_status,
> @@ -686,7 +699,8 @@ static int tpm_cr50_i2c_probe(struct i2c_client *client)
>  
>  	/* cr50 is a TPM 2.0 chip */
>  	chip->flags |= TPM_CHIP_FLAG_TPM2;
> -	chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
> +	if (tpm_cr50_i2c_is_firmware_power_managed(dev))
> +		chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
>  
>  	/* Default timeouts */
>  	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
> diff --git a/drivers/char/tpm/tpm_tis_spi_cr50.c b/drivers/char/tpm/tpm_tis_spi_cr50.c
> index dae98dbeeeac..7bf123d3c537 100644
> --- a/drivers/char/tpm/tpm_tis_spi_cr50.c
> +++ b/drivers/char/tpm/tpm_tis_spi_cr50.c
> @@ -185,6 +185,19 @@ static int cr50_spi_flow_control(struct tpm_tis_spi_phy *phy,
>  	return 0;
>  }
>  
> +static bool tpm_cr50_spi_is_firmware_power_managed(struct device *dev)
> +{
> +	u8 val;
> +	int ret;
> +
> +	/* This flag should default true when the device property is not present */
> +	ret = device_property_read_u8(dev, "firmware-power-managed", &val);
> +	if (ret)
> +		return true;
> +
> +	return val;
> +}
> +
>  static int tpm_tis_spi_cr50_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
>  				     u8 *in, const u8 *out)
>  {
> @@ -309,7 +322,8 @@ int cr50_spi_probe(struct spi_device *spi)
>  	cr50_print_fw_version(&phy->priv);
>  
>  	chip = dev_get_drvdata(&spi->dev);
> -	chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
> +	if (tpm_cr50_spi_is_firmware_power_managed(&spi->dev))
> +		chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
>  
>  	return 0;
>  }

Thank you.

Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>

I applied this to my tree, and it should be visible in linux-next soon.

/Jarkko