Re: [PATCH] tpm/tpm_crb: revamp starting method setting.

From: Jarkko Sakkinen
Date: Wed Oct 05 2016 - 11:19:58 EST


On Wed, Oct 05, 2016 at 04:12:08PM +0300, Tomas Winkler wrote:
> Encapsulate the start method parsing in a single function
> and add needed debug printouts.
> It eliminates small issue with useless double checking for
> ACPI_TPM2_MEMORY_MAPPED.

Start method is trival to check from TPM2 dump. I'm not sure which
problem is this commit trying to solve.

/Jarkko

> Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
> ---
> drivers/char/tpm/tpm_crb.c | 65 +++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 50 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index aa0ef742ac03..aeec313384d7 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -381,6 +381,52 @@ out:
> return ret;
> }
>
> +/**
> + * crb_start_method - parse starting method
> + *
> + * @device: acpi device
> + * @sm: starting method
> + *
> + * Return 0 if supported starting method was not found
> + * CRB_FL_CRB_START or CRB_FL_ACPI_START otherwise
> + */
> +static unsigned int crb_start_method(struct acpi_device *device, u32 sm)
> +{
> + struct device *dev = &device->dev;
> + u32 flags;
> +
> + switch (sm) {
> + /* Should the FIFO driver handle this? */
> + case ACPI_TPM2_MEMORY_MAPPED:
> + dev_dbg(dev, "starting method[%d]: MM\n", sm);
> + return 0;
> + case ACPI_TPM2_COMMAND_BUFFER:
> + flags = CRB_FL_CRB_START;
> + dev_dbg(dev, "starting method[%d]: CB\n", sm);
> + break;
> + case ACPI_TPM2_START_METHOD:
> + flags = CRB_FL_ACPI_START;
> + dev_dbg(dev, "starting method[%d]: SM\n", sm);
> + break;
> + case ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD:
> + flags = CRB_FL_ACPI_START;
> + dev_dbg(dev, "starting method[%d]: CB w/ SM\n",
> + sm);
> + break;
> + default:
> + return 0;
> + }
> +
> + /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
> + * report only ACPI start but in practice seems to require both
> + * ACPI start and CRB start.
> + */
> + if (!strcmp(acpi_device_hid(device), "MSFT0101"))
> + flags |= CRB_FL_CRB_START;
> +
> + return flags;
> +}
> +
> static int crb_acpi_add(struct acpi_device *device)
> {
> struct acpi_table_tpm2 *buf;
> @@ -388,7 +434,7 @@ static int crb_acpi_add(struct acpi_device *device)
> struct tpm_chip *chip;
> struct device *dev = &device->dev;
> acpi_status status;
> - u32 sm;
> + unsigned int sm;
> int rc;
>
> status = acpi_get_table(ACPI_SIG_TPM2, 1,
> @@ -398,26 +444,15 @@ static int crb_acpi_add(struct acpi_device *device)
> return -EINVAL;
> }
>
> - /* Should the FIFO driver handle this? */
> - sm = buf->start_method;
> - if (sm == ACPI_TPM2_MEMORY_MAPPED)
> + sm = crb_start_method(device, buf->start_method);
> + if (!sm)
> return -ENODEV;
>
> priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
>
> - /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
> - * report only ACPI start but in practice seems to require both
> - * ACPI start and CRB start.
> - */
> - if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
> - !strcmp(acpi_device_hid(device), "MSFT0101"))
> - priv->flags |= CRB_FL_CRB_START;
> -
> - if (sm == ACPI_TPM2_START_METHOD ||
> - sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
> - priv->flags |= CRB_FL_ACPI_START;
> + priv->flags = sm;
>
> rc = crb_map_io(device, priv, buf);
> if (rc)
> --
> 2.7.4
>