Re: [PATCH v4 1/3] xen/arm: Add imx8q{m,x} platform glue

[Michal Orzel <michal.orzel@xxxxxxx>]

Hi John,

On 08/04/2024 18:11, John Ernberg wrote:
> 
> 
> When using Linux for dom0 there are a bunch of drivers that need to do SMC
> SIP calls into the firmware to enable certain hardware bits like the
> watchdog.
> 
> Provide a basic platform glue that implements the needed SMC forwarding.
> 
> The format of these calls are as follows:
>  - reg 0: function ID
>  - reg 1: subfunction ID (when there's a subfunction)
>  remaining regs: args
> 
> For now we only allow Dom0 to make these calls as they are all managing
> hardware. There is no specification for these SIP calls, the IDs and names
> have been extracted from the upstream linux kernel and the vendor kernel.
> 
> Most of the SIP calls are only available for the iMX8M series of SoCs, so
> they are easy to reject and they need to be revisited when iMX8M series
> support is added.
Stale paragraph. Should be removed given that the driver targets only Q{M,XP}.

> 
> From the other calls we can reject CPUFREQ because Dom0 cannot make an
> informed decision regarding CPU frequency scaling, WAKEUP_SRC is to wake
> up from suspend, which Xen doesn't support at this time.
> 
> This leaves the TIME SIP, OTP SIPs, BUILDINFO SIP and TEMP ALARM SIP, which
> for now are allowed to Dom0.
BUILDINFO, TEMP ALARM are leftovers from previous revision.

> 
> NOTE: This code is based on code found in NXP Xen tree located here:
> https://github.com/nxp-imx/imx-xen/blob/lf-5.10.y_4.13/xen/arch/arm/platforms/imx8qm.c
> 
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> [jernberg: Add SIP call filtering]
> Signed-off-by: John Ernberg <john.ernberg@xxxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

The commit msg can be fixed on commit.

~Michal