From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
To: Pavel Machek <pavel@denx.de>,
Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Cc: "cip-dev@lists.cip-project.org" <cip-dev@lists.cip-project.org>,
Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
Biju Das <biju.das.jz@bp.renesas.com>
Subject: Backporting Renesas IA55 IRQC driver
Date: Fri, 15 Mar 2024 15:18:56 +0000 [thread overview]
Message-ID: <TYCPR01MB64784B67B1AD38E99F08C2ED9F282@TYCPR01MB6478.jpnprd01.prod.outlook.com> (raw)
Hi, CIP maintainers,
I'm trying to backport the IA55 IRQC driver [1] to v5.10.209-cip44.
The controller is connected to GIC and pin controller as follows:
┌──────────┐ ┌──────────┐
│ │ SPIX │ │
│ ├─────────►│ │
│ │ │ │
│ │ │ │
┌────────┐IRQ0-7 │ IA55 │ │ GIC │
Pin0 ───────►│ ├─────────────►│ │ │ │
│ │ │ │ PPIY │ │
... │ GPIO │ │ ├─────────►│ │
│ │GPIOINT0-127 │ │ │ │
PinN ───────►│ ├─────────────►│ │ │ │
└────────┘ └──────────┘ └──────────┘
While working on mainline driver, my colleague, Prabhakar, found that there
are issues with this kind of hierarchy due to
platform_get_resource(pdev, IORESOURCE_IRQ, ...) which relies on static
allocation of IRQ resources in DT core code causing issues
when using hierarchical interrupt domains with "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
As a result he run a cleanup campaign in mainline kernel and changed
drivers from using platform_get_resource(pdev, IORESOURCE_IRQ, ...)
to platform_get_irq(pdev, ...) (see list here [2]) and at the submitting [3].
Now we want to backport the IA55 driver to v5.10.209-cip44 (in the first instance).
At the moment we have 2 working approaches:
1/ backport all the work that Prabhakar did (I counted ~80 commits)
2/ change the mainline IA55 driver to not use the interrupts bindings
to describe the interrupts (see [4] for the mainline approach)
but another DT property (we have a working version that uses
interrupt-map and interrupt-map-mask) and adapt the
rzg2l_irqc_parse_interrupts() to do the proper mapping
The issue we see with 1 is that it affects multiple drivers but not only Renesas ones.
The issue we see with 2 is that the DT bindings are changed and we don't know
if we should keep the DTB as ABI: should a CIP DTB be able to work with a mainline
kernel? Should a mainline DTB be able to work with a CIP kernel?
Could you please share your knowledge on this?
What solution would you prefer?
Thank you,
Claudiu Beznea
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/irqchip/irq-renesas-rzg2l.c
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=Use+platform_get_irq%28%29+to+get+the+interrupt
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/of/platform.c?id=a1a2b7125e1079cfcc13a116aa3af3df2f9e002b
[4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/interrupt-controller/renesas,rzg2l-irqc.yaml#n196
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next reply other threads:[~2024-03-15 15:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-15 15:18 Claudiu Beznea [this message]
2024-03-15 18:31 ` Backporting Renesas IA55 IRQC driver Jan Kiszka
2024-03-18 12:00 ` Pavel Machek
2024-03-18 12:12 ` Pavel Machek
2024-03-18 15:49 ` Claudiu Beznea
2024-03-18 19:01 ` Pavel Machek
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