[U-Boot] [PATCH] imx: mx7: psci: Add support for version command

[U-Boot] [PATCH] imx: mx7: psci: Add support for version command

[Trent Piepho]

This command should be supported for PSCI 1.0.  Current code results in
this message from the kernel:  "PSCIv65535.65535 detected in firmware."

This will mess up a kernel check of the PSCI version.  Currently the
kernel only cares if the version is at least 1.0 so it doesn't break
anything, as the incorrect version and correct version are both >= 1.0,
but as soon as a check for > 1.0 goes in it will fail.

CC: Anson Huang <Anson.Huang@nxp.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Signed-off-by: Trent Piepho <tpiepho@impinj.com>
---
 arch/arm/mach-imx/mx7/psci.S | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm/mach-imx/mx7/psci.S b/arch/arm/mach-imx/mx7/psci.S
index 89dcf880e8..7035f6093b 100644
--- a/arch/arm/mach-imx/mx7/psci.S
+++ b/arch/arm/mach-imx/mx7/psci.S
@@ -57,4 +57,14 @@ psci_system_off:
 3: 	wfi
 	b 3b
 
+.globl psci_version
+psci_version:
+#if defined(CONFIG_ARMV7_PSCI_1_0)
+	ldr	r0, =ARM_PSCI_VER_1_0
+#else
+#error "add support for your PSCI version"
+#endif
+
+	bx	lr
+
 	.popsection
-- 
2.14.3

[U-Boot] [PATCH] imx: mx7: psci: Add support for version command

[Stefan Agner]

On 31.05.2018 20:13, Trent Piepho wrote:
> This command should be supported for PSCI 1.0.  Current code results in
> this message from the kernel:  "PSCIv65535.65535 detected in firmware."
> 
> This will mess up a kernel check of the PSCI version.  Currently the
> kernel only cares if the version is at least 1.0 so it doesn't break
> anything, as the incorrect version and correct version are both >= 1.0,
> but as soon as a check for > 1.0 goes in it will fail.

The right direction, it can also be done in C though:

unsigned int __secure psci_version(u32 function_id)
{
	return ARM_PSCI_VER_1_0;
}

But this is not complete though, since also other callbacks need to be
supported for proper PSCI 1.0 support.

See also this discussion:
https://www.spinics.net/lists/arm-kernel/msg640337.html

I try to come up with a proper fix for this.

--
Stefan

> 
> CC: Anson Huang <Anson.Huang@nxp.com>
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> Cc: Peng Fan <peng.fan@nxp.com>
> Cc: Stefano Babic <sbabic@denx.de>
> Signed-off-by: Trent Piepho <tpiepho@impinj.com>
> ---
>  arch/arm/mach-imx/mx7/psci.S | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/mx7/psci.S b/arch/arm/mach-imx/mx7/psci.S
> index 89dcf880e8..7035f6093b 100644
> --- a/arch/arm/mach-imx/mx7/psci.S
> +++ b/arch/arm/mach-imx/mx7/psci.S
> @@ -57,4 +57,14 @@ psci_system_off:
>  3: 	wfi
>  	b 3b
>  
> +.globl psci_version
> +psci_version:
> +#if defined(CONFIG_ARMV7_PSCI_1_0)
> +	ldr	r0, =ARM_PSCI_VER_1_0
> +#else
> +#error "add support for your PSCI version"
> +#endif
> +
> +	bx	lr
> +
>  	.popsection

[U-Boot] [PATCH] imx: mx7: psci: Add support for version command

[Trent Piepho]

On Fri, 2018-06-22 at 11:09 +0200, Stefan Agner wrote:
> On 31.05.2018 20:13, Trent Piepho wrote:
> > This command should be supported for PSCI 1.0.  Current code results in
> > this message from the kernel:  "PSCIv65535.65535 detected in firmware."
> > 
> > This will mess up a kernel check of the PSCI version.  Currently the
> > kernel only cares if the version is at least 1.0 so it doesn't break
> > anything, as the incorrect version and correct version are both >= 1.0,
> > but as soon as a check for > 1.0 goes in it will fail.
> 
> The right direction, it can also be done in C though:
> 
> unsigned int __secure psci_version(u32 function_id)
> {
> 	return ARM_PSCI_VER_1_0;
> }

When the PSCI is left in RAM, does it consist of the entire u-boot
image, or is somehow just the PSCI component left?

I'm curious how placing the code in another object file affects the
PSCI binary.

> But this is not complete though, since also other callbacks need to be
> supported for proper PSCI 1.0 support.
> 
> See also this discussion:

I see this problem was known before I found it.  It would be nice if a
fix could go in before others also find it and waste time
investigating.

It is also the case the reset code in the PSCI does not work on imx7
for some time now, for boards with a reset design following NXP's
recommendations.  This is not hard to change, I've already done so
locally for our product affected by this.

Must these problems remain unaddressed until some future redesign or
major patch from NXP fixes them?