[SeaBIOS] [PATCH v1 3/3] tpm: Handle unimplemented TIS_REG_IFACE_ID in tis_get_tpm_version()

[Stefan Berger]

On 02/27/2018 02:17 PM, Stephen Douthit wrote:
> If a device reports 0xf in the InterfaceType field of the TPM_INTERFACE_ID,
> then the rest of the fields are invalid, and the InterfaceVersion field of
> the TPM_INTF_CAPABILITY register must be checked instead.
>
> Signed-off-by: Stephen Douthit <stephend at silicom-usa.com>
> ---
>   src/hw/tpm_drivers.c | 20 +++++++++++++++-----
>   1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
> index da8bb63..ed58bf5 100644
> --- a/src/hw/tpm_drivers.c
> +++ b/src/hw/tpm_drivers.c
> @@ -142,13 +142,23 @@ static u32 tis_probe(void)
>
>   static TPMVersion tis_get_tpm_version(void)
>   {
> -    /* TPM 2 has an interface register */
> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
> -
> -    if ((ifaceid & 0xf) == 0) {
> -        /* TPM 2 */
> +    u32 reg = readl(TIS_REG(0, TIS_REG_IFACE_ID));
> +
> +    /*
> +     * FIFO interface as defined in TIS1.3 is active
> +     * Interface capabilities are defined in TIS_REG_INTF_CAPABILITY
> +     */
> +    if ((reg & 0xf) == 0xf) {
> +        reg = readl(TIS_REG(0, TIS_REG_INTF_CAPABILITY));
> +        /* Interface 1.3 for TPM 2.0 */
> +        if (((reg >> 28) & 0x7) == 3)
> +            return TPM_VERSION_2;
> +    }
> +    /* FIFO interface as defined in PTP for TPM 2.0 is active */
> +    else if ((reg & 0xf) == 0) {
>           return TPM_VERSION_2;
>       }
> +
>       return TPM_VERSION_1_2;
>   }
>
Tested it with QEMU TPM 2 and TPM 1.2:

Tested-by: Stefan Berger <stefanb at linux.vnet.ibm.com>

Reviewed-by: Stefan Berger <stefanb at linux.vnet.ibm.com>