This is based on wait_startup() from the Linux tpm_tis driver.

Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
Tested-by: Stephen Douthit <stephend@silicom-usa.com>
---
 src/hw/tpm_drivers.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
index 8d6fc33..789d70a 100644
--- a/src/hw/tpm_drivers.c
+++ b/src/hw/tpm_drivers.c
@@ -86,6 +86,11 @@ static u32 wait_reg8(u8* reg, u32 time, u8 mask, u8 expect)
     return rc;
 }
 
+static u32 tis_wait_access(u8 locty, u32 time, u8 mask, u8 expect)
+{
+    return wait_reg8(TIS_REG(locty, TIS_REG_ACCESS), time, mask, expect);
+}
+
 static u32 tis_wait_sts(u8 locty, u32 time, u8 mask, u8 expect)
 {
     return wait_reg8(TIS_REG(locty, TIS_REG_STS), time, mask, expect);
@@ -102,7 +107,13 @@ static u32 tis_probe(void)
     if (!CONFIG_TCGBIOS)
         return 0;
 
-    u32 rc = 0;
+    /* Wait for the interface to report it's ready */
+    u32 rc = tis_wait_access(0, TIS_DEFAULT_TIMEOUT_A,
+                             TIS_ACCESS_TPM_REG_VALID_STS,
+                             TIS_ACCESS_TPM_REG_VALID_STS);
+    if (rc)
+        return 0;
+
     u32 didvid = readl(TIS_REG(0, TIS_REG_DID_VID));
 
     if ((didvid != 0) && (didvid != 0xffffffff))
-- 
2.14.3


_______________________________________________
SeaBIOS mailing list
SeaBIOS@seabios.org
https://mail.coreboot.org/mailman/listinfo/seabios

On 02/26/2018 03:37 PM, Stephen Douthit wrote:
> This is based on wait_startup() from the Linux tpm_tis driver.
>
> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
> ---
>   src/hw/tpm_drivers.c | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
> index 8d6fc33..789d70a 100644
> --- a/src/hw/tpm_drivers.c
> +++ b/src/hw/tpm_drivers.c
> @@ -86,6 +86,11 @@ static u32 wait_reg8(u8* reg, u32 time, u8 mask, u8 expect)
>       return rc;
>   }
>
> +static u32 tis_wait_access(u8 locty, u32 time, u8 mask, u8 expect)
> +{
> +    return wait_reg8(TIS_REG(locty, TIS_REG_ACCESS), time, mask, expect);
> +}
> +
>   static u32 tis_wait_sts(u8 locty, u32 time, u8 mask, u8 expect)
>   {
>       return wait_reg8(TIS_REG(locty, TIS_REG_STS), time, mask, expect);
> @@ -102,7 +107,13 @@ static u32 tis_probe(void)
>       if (!CONFIG_TCGBIOS)
>           return 0;
>
> -    u32 rc = 0;
> +    /* Wait for the interface to report it's ready */
> +    u32 rc = tis_wait_access(0, TIS_DEFAULT_TIMEOUT_A,
> +                             TIS_ACCESS_TPM_REG_VALID_STS,
> +                             TIS_ACCESS_TPM_REG_VALID_STS);
> +    if (rc)
> +        return 0;
> +
>       u32 didvid = readl(TIS_REG(0, TIS_REG_DID_VID));
>
>       if ((didvid != 0) && (didvid != 0xffffffff))


On QEMU that VALID flag is always set.

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



_______________________________________________
SeaBIOS mailing list
SeaBIOS@seabios.org
https://mail.coreboot.org/mailman/listinfo/seabios