From patchwork Tue Feb 6 12:27:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lad Prabhakar X-Patchwork-Id: 13547172 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id C62EAC48297 for ; Tue, 6 Feb 2024 12:28:15 +0000 (UTC) Received: from relmlie5.idc.renesas.com (relmlie5.idc.renesas.com [210.160.252.171]) by mx.groups.io with SMTP id smtpd.web11.20157.1707222466534019812 for ; Tue, 06 Feb 2024 04:28:06 -0800 Authentication-Results: mx.groups.io; dkim=none (message not signed); spf=pass (domain: bp.renesas.com, ip: 210.160.252.171, mailfrom: prabhakar.mahadev-lad.rj@bp.renesas.com) X-IronPort-AV: E=Sophos;i="6.05,247,1701097200"; d="scan'208";a="193048726" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 06 Feb 2024 21:28:05 +0900 Received: from Ubuntu-22.. (unknown [10.226.93.78]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id 2C85C4005E16; Tue, 6 Feb 2024 21:28:03 +0900 (JST) From: Lad Prabhakar To: cip-dev@lists.cip-project.org, Nobuhiro Iwamatsu , Pavel Machek Cc: Biju Das Subject: [PATCH v2 5.10.y-cip 14/44] of/irq: Use interrupts-extended to find parent Date: Tue, 6 Feb 2024 12:27:04 +0000 Message-Id: <20240206122734.13477-15-prabhakar.mahadev-lad.rj@bp.renesas.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240206122734.13477-1-prabhakar.mahadev-lad.rj@bp.renesas.com> References: <20240206122734.13477-1-prabhakar.mahadev-lad.rj@bp.renesas.com> MIME-Version: 1.0 List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Tue, 06 Feb 2024 12:28:15 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/14798 From: Samuel Holland commit e91033621d56e055803c4c4ba507fbbb2d145a7f upstream. The RISC-V PLIC binding uses interrupts-extended to specify its parent domain(s). That binding does not allow the interrupt-parent property to appear in the irqchip node. This prevents of_irq_init from properly detecting the irqchip hierarchy. If no interrupt-parent property is present in the enclosing bus or root node, then desc->interrupt_parent will be NULL for both the per-CPU RISC-V INTC (the actual root domain) and the RISC-V PLIC. Similarly, if the bus or root node specifies `interrupt-parent = <&plic>`, then of_irq_init will hit the `desc->interrupt_parent == np` check, and again all parents will be NULL. So things happen to work today for some boards due to Makefile ordering. However, things break when another irqchip ("foo") is stacked on top of the PLIC. The bus or root node will have `interrupt-parent = <&foo>`, since that is what all of the other peripherals need. When of_irq_init runs, it will try to find the PLIC's parent domain. of_irq_find_parent will fall back to using the interrupt-parent property of the PLIC's parent node (i.e. the bus or root node), and of_irq_init will see "foo" as the PLIC's parent domain. But this is wrong, because "foo" is actually the PLIC's child domain! So of_irq_init wrongly attempts to init the stacked irqchip before the PLIC. This fails and breaks booting. Fix this by using the first node referenced by interrupts-extended as the parent when that property is present. This allows of_irq_init to see the relationship between the PLIC and the per-CPU RISC-V INTC, and thus only the RISC-V INTC is (correctly) considered a root domain. Signed-off-by: Samuel Holland Signed-off-by: Rob Herring Link: https://lore.kernel.org/r/20220412051529.6293-1-samuel@sholland.org Signed-off-by: Lad Prabhakar Reviewed-by: Nobuhiro Iwamatsu --- drivers/of/irq.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/of/irq.c b/drivers/of/irq.c index 352e14b007e78..7f84e7649dc5b 100644 --- a/drivers/of/irq.c +++ b/drivers/of/irq.c @@ -507,9 +507,18 @@ void __init of_irq_init(const struct of_device_id *matches) desc->irq_init_cb = match->data; desc->dev = of_node_get(np); - desc->interrupt_parent = of_irq_find_parent(np); - if (desc->interrupt_parent == np) + /* + * interrupts-extended can reference multiple parent domains. + * Arbitrarily pick the first one; assume any other parents + * are the same distance away from the root irq controller. + */ + desc->interrupt_parent = of_parse_phandle(np, "interrupts-extended", 0); + if (!desc->interrupt_parent) + desc->interrupt_parent = of_irq_find_parent(np); + if (desc->interrupt_parent == np) { + of_node_put(desc->interrupt_parent); desc->interrupt_parent = NULL; + } list_add_tail(&desc->list, &intc_desc_list); }