[PATCH] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1

[PATCH] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1

[Sascha Hauer]

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@pengutronix.de>
---
 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 = {
+		.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();
+
 	return 0;
 }
 
-- 
2.39.2

Re: [PATCH] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1

[Ahmad Fatoum]

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@pengutronix.de>
> ---
>  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.

> +		.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?
At the least, I'd prefer this to be rev >= 0xa1, so it need not be debugged
again in the future.

Thoughts?

Ahmad

> +
>  	return 0;
>  }
>  

-- 
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Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
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Re: [PATCH] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1

[Sascha Hauer]

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@pengutronix.de>
> > ---
> >  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

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1

[Sascha Hauer]

On Mon, 11 Mar 2024 09:06:24 +0100, 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.
> 
> 

Applied, thanks!

[1/1] ARM: i.MX93: ele: start TRNG on i.MX93 rev a1
      https://git.pengutronix.de/cgit/barebox/commit/?id=d27c50c131e7 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>