From: Yao Zi <ziyao@disroot.org>
To: Drew Fustini <fustini@kernel.org>,
Michal Wilczynski <m.wilczynski@samsung.com>
Cc: Guo Ren <guoren@kernel.org>, Fu Wei <wefu@redhat.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, Icenowy Zheng <uwu@icenowy.me>
Subject: Re: [PATCH] reset: thead: Scope TH1520 reset driver to VO subsystem
Date: Wed, 13 Aug 2025 08:04:40 +0000 [thread overview]
Message-ID: <aJxGnnwlE1sWarXa@pie> (raw)
In-Reply-To: <aJrTq775sXTrsepl@x1>
On Mon, Aug 11, 2025 at 10:39:55PM -0700, Drew Fustini wrote:
> On Sun, Aug 10, 2025 at 11:14:19PM +0200, Michal Wilczynski wrote:
> > The reset controller driver for the TH1520 was using the generic
> > compatible string "thead,th1520-reset". However, the current
> > implementation only manages the resets for the Video Output (VO)
> > subsystem.
>
> Looking at Section 5.4 on Page 451 of the TH1520 System User Manual [1],
> it does seem like we would ultimately need 6 separate nodes for reset
> controllers:
Yes, this is true. And another six nodes for clock controllers (there's
already one).
> 0xFF_EF01_4000: AP_SUBSYS
> 0xFF_EC02_C000: MISC_SUBSYS
> 0xFF_E404_0000: VI_SUBSYS
> 0xFF_EF52_8000: VO_SUBSYS
> 0xFF_ECC3_0000: VP_SUBSYS
> 0xFF_EF04_0000: DSP_SUBSYS
>
> Maybe we should take this opportunity to document the bindings for all
> the resets that the REE (e.g. Linux) can control?
It's worth noting that with either mainline U-Boot or vendor U-Boot, no
core is configured to run as REE. IOW, AON_SUBSYS could be accessed by
AP cores as well.
I think introducing read-only clock support to Linux could help us to
correctly describe pvt clocks which are now replaced with a aonsys
placeholder and resolve issues like what is described in 0370395d45ca
("clk: thead: Mark essential bus clocks as CLK_IGNORE_UNUSED").
Futhermore, there may be downstream projects, e.g. U-Boot, make use of
these TEE-only devices, which could benefit if we have these devices
documented and described in devicetree, too. Thus I think the AON clock
and reset controllers should be documented as well if we're going to
document every reset/clock controller in a batch.
> It seemed like that was overkill for the 2 resets needed for the GPU,
> but, as Krzysztof noted in this thread, problems arise when bindings are
> introduced that are not complete.
>
> Thanks,
> Drew
>
> [1] https://git.beagleboard.org/beaglev-ahead/beaglev-ahead/-/blob/main/docs/TH1520%20System%20User%20Manual.pdf
Best regards,
Yao Zi
next prev parent reply other threads:[~2025-08-13 8:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20250810211419eucas1p173e5fefcfaae437d8b5531d1406ff6a6@eucas1p1.samsung.com>
2025-08-10 21:14 ` [PATCH] reset: thead: Scope TH1520 reset driver to VO subsystem Michal Wilczynski
2025-08-11 2:23 ` Yao Zi
2025-08-11 6:43 ` Krzysztof Kozlowski
2025-08-12 5:39 ` Drew Fustini
2025-08-13 8:04 ` Yao Zi [this message]
2025-08-13 18:48 ` Drew Fustini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aJxGnnwlE1sWarXa@pie \
--to=ziyao@disroot.org \
--cc=alex@ghiti.fr \
--cc=aou@eecs.berkeley.edu \
--cc=conor+dt@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=fustini@kernel.org \
--cc=guoren@kernel.org \
--cc=krzk+dt@kernel.org \
--cc=krzysztof.kozlowski@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=m.wilczynski@samsung.com \
--cc=p.zabel@pengutronix.de \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=robh@kernel.org \
--cc=uwu@icenowy.me \
--cc=wefu@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).