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

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Message-ID: <CA+Dqm30i6axAHkB4Dagu8uN-_Vx56RiWPVYqheddLjvvYoT0dQ@mail.gmail.com>
Date:   Mon, 6 Dec 2021 16:52:39 -0700
From:   Rob Barnes <robbarnes@...gle.com>
To:     Peter Huewe <peterhuewe@....de>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Jason Gunthorpe <jgg@...pe.ca>
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        tpmdd-devel@...ts.sourceforge.net
Subject: Re: [PATCH] char: tpm: cr50: Set TPM_FIRMWARE_POWER_MANAGED based on
 device property

Including tpmdd-devel@...ts.sourceforge.net

>
> 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 | 14 +++++++++++++-
>  drivers/char/tpm/tpm_tis_spi_cr50.c | 14 +++++++++++++-
>  2 files changed, 26 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..70143cc4f4e8 100644
> --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
> +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> @@ -628,6 +628,17 @@ 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 1;
> +       return val;
> +}
> +
>  static const struct tpm_class_ops cr50_i2c = {
>         .flags = TPM_OPS_AUTO_STARTUP,
>         .status = &tpm_cr50_i2c_tis_status,
> @@ -686,7 +697,8 @@ 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..e01f7cc258ca 100644
> --- a/drivers/char/tpm/tpm_tis_spi_cr50.c
> +++ b/drivers/char/tpm/tpm_tis_spi_cr50.c
> @@ -185,6 +185,17 @@ 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 1;
> +       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 +320,8 @@ 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(dev))
> +               chip->flags |= TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED;
>
>         return 0;
>  }
> --
> 2.34.0.rc2.393.gf8c9666880-goog
>