linux-kernel - Re: [PATCH 4/5] remoteproc: meson-mx-ao-arc: Add a driver for the AO ARC remote procesor

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Message-ID: <CAFBinCBx1GtN_CYqOorfKVgXq8utXAr04ab815sVbNH5+qGBQQ@mail.gmail.com>
Date:   Tue, 23 Mar 2021 22:36:29 +0100
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     linux-remoteproc@...r.kernel.org,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, ohad@...ery.com, robh+dt@...nel.org
Subject: Re: [PATCH 4/5] remoteproc: meson-mx-ao-arc: Add a driver for the AO
 ARC remote procesor

Hi Bjorn,

On Thu, Mar 18, 2021 at 3:51 AM Bjorn Andersson
<bjorn.andersson@...aro.org> wrote:
>
> On Tue 29 Dec 19:27 CST 2020, Martin Blumenstingl wrote:
>
> > Amlogic Meson6, Meson8, Meson8b and Meson8m2 embed an ARC core in the
> > Always-On (AO) power-domain. This is typically used for waking up the
> > ARM cores after system suspend.
> >
> > The configuration is spread across three different registers:
> > - AO_REMAP_REG0 which must be programmed to zero, it's actual purpose
> >   is unknown. There is a second remap register which is not used in the
> >   vendor kernel (which served as reference for this driver).
> > - AO_CPU_CNTL is used to start and stop the ARC core.
> > - AO_SECURE_REG0 in the SECBUS2 register area with unknown purpose.
> >
> > To boot the ARC core we also need to enable it's gate clock and trigger
> > a reset.
> >
> > The actual code for this ARC core can come from an ELF binary, for
> > example by building the Zephyr RTOS for an ARC EM4 core and then taking
> > "zephyr.elf" as firmware. This executable does not have any "rsc table"
> > so we are skipping rproc_elf_load_rsc_table (rproc_ops.parse_fw) and
> > rproc_elf_find_loaded_rsc_table (rproc_ops.find_loaded_rsc_table).
> >
>
> Thanks for the patch Martin, it looks really good. Just some minor
> things as I expect a respin of the DT binding as well.
thank you for your comments.
I will send an updated series in the next few days and include all of
your suggested changes

since I sent this series (it's been a few days) I also got an update
from Amlogic so I know have better understanding of some (but
unfortunately not all) registers
so it'll be a bigger update. but don't worry: I'll include a changelog


Best regards,
Martin