On Mon, Mar 11, 2024 at 09:20:07AM +0100, Ahmad Fatoum wrote:
> Hello Sascha,
>
> On 11.03.24 09:06, Sascha Hauer wrote:
> > On i.MX93 a0 the TRNG seems to be started automatically. On rev a1 it's
> > not and OP-TEE panics with "Cannot retrieve random data from ELE". Start
> > the TRNG to let OP-TEE startup successfully.
> >
> > Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > ---
> > arch/arm/mach-imx/ele.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/arch/arm/mach-imx/ele.c b/arch/arm/mach-imx/ele.c
> > index ab3958cbd3..f8093fc694 100644
> > --- a/arch/arm/mach-imx/ele.c
> > +++ b/arch/arm/mach-imx/ele.c
> > @@ -165,6 +165,23 @@ int ele_get_info(struct ele_get_info_data *info)
> > return ret;
> > }
> >
> > +static int ele_get_start_trng(void)
> > +{
> > + struct ele_msg msg = {
>
> strange indentation.
Fixed.
>
> > + .version = ELE_VERSION,
> > + .tag = ELE_CMD_TAG,
> > + .size = 1,
> > + .command = ELE_START_RNG,
> > + };
> > + int ret;
> > +
> > + ret = ele_call(&msg);
> > + if (ret)
> > + pr_err("Could not start TRNG, response 0x%x\n", msg.data[0]);
> > +
> > + return ret;
> > +}
> > +
> > int imx93_ele_load_fw(void *bl33)
> > {
> > struct ele_get_info_data info = {};
> > @@ -204,6 +221,9 @@ int imx93_ele_load_fw(void *bl33)
> > pr_err("Could not start ELE firmware: ret %d, response 0x%x\n",
> > ret, msg.data[0]);
> >
> > + if (rev == 0xa1)
> > + ele_get_start_trng();
>
> Does it hurt to start it unconditionally, even if it's already enabled?
I don't know and I don't have the a0 board available at the moment. I'll
test this once I have the board connected again, but for now I think
I'll only do this for the a1 board where I know it's needed.
> At the least, I'd prefer this to be rev >= 0xa1, so it need not be debugged
> again in the future.
Changed that. We don't know what we have to do on a new SoC revision anyway,
so it could be wrong either way. Note this is directly below this code:
switch (rev) {
case 0xa0:
get_builtin_firmware_ext(mx93a0_ahab_container_img, bl33, &firmware, &size);
break;
case 0xa1:
get_builtin_firmware_ext(mx93a1_ahab_container_img, bl33, &firmware, &size);
break;
default:
pr_err("Unknown unhandled SoC revision %2x\n", rev);
return -EINVAL;
}
So we'll need to touch this place anyway once we get a new SoC revision.
Sascha
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