From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 32DD5C52D7C for ; Sun, 18 Aug 2024 16:19:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=e7pa/09DxXgqUkf8DtvGHybCmLcny+zZXh5eB1MJOGI=; b=Gb5aHwiFiymdJlCR3lRu68FjNo +S1aa8xMTOh/8+yYW0vOnU/4ifBbFpTXyKTrHhkaNTW/tu1NGohTlLpgpbUUVQmXn1UFIepFZHfQk yWmlc8ux0ZwJ6Uo/4qLZuvW4/KUom73BYLu2t+DKznfNHDPOSKMRNnjpOOe7kULb1xlMmJ41IC03G RaM/FyDsR5JEAyo2ZW8VIFWmDh0orOOyBO3CWe6Zfh6txjC69Mp5+Jo636FOWOYUOmlMR5ujMys6m h/i1ZGiKwwuUwoV21nG5adpNmgXwmB2pAhSJTeGvsLGfVzjSftmtKjPkssOcZXsYCoWD8Soy+Gjmv BjVtJb6A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sficP-0000000GoKv-1iyX; Sun, 18 Aug 2024 16:19:01 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sfibj-0000000GoHT-2EY1; Sun, 18 Aug 2024 16:18:21 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A91A461008; Sun, 18 Aug 2024 16:18:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBB6EC32786; Sun, 18 Aug 2024 16:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723997898; bh=wH/q17EcEM1yaX/QyJjRxmoKQTkpYh+1vI+c83h+e30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ctyjVRbNpRe4lev974iUalRA4DqpO46Do2yiZunEtwRcmp3yo0ZHP6kHW3VrFU+FV Y4I1tIa4iTf9P+SZzFQpCvf/mSt68b1PGIzWBBf0Z+ufxM/mL+y1jH3m1lCi2mBHSL acxPNNUBHzs0zHkl/S1n+yKJ01mzije5DlWPLPdSwF5BrpoJLKHFzmff/ikaCrVp/b I2TnEjvvw7LFo8cBqIRnoG3dvxplAtjz5Zro+jyajxgpZv/odJfk0uUCEX8gTazYhs 5lT1QL5ZE2i317aWsnN2AOryK3AvXWP5Aj5gQrSdtWmnHmNK7EVBmw9ENpRxhLL8dq dE+NsgFLVlhJg== Date: Sun, 18 Aug 2024 10:18:16 -0600 From: Rob Herring To: Andrew Jones Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, maz@kernel.org, mark.rutland@arm.com, saravanak@google.com, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, Anup Patel Subject: Re: [PATCH v3] of/irq: Support #msi-cells=<0> in of_msi_get_domain Message-ID: <20240818161816.GA173148-robh@kernel.org> References: <20240817074107.31153-2-ajones@ventanamicro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240817074107.31153-2-ajones@ventanamicro.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240818_091819_701060_119474C6 X-CRM114-Status: GOOD ( 28.40 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Aug 17, 2024 at 09:41:08AM +0200, Andrew Jones wrote: > An 'msi-parent' property with a single entry and no accompanying > '#msi-cells' property is considered the legacy definition as opposed > to its definition after being expanded with commit 126b16e2ad98 > ("Docs: dt: add generic MSI bindings"). However, the legacy > definition is completely compatible with the current definition and, > since of_phandle_iterator_next() tolerates missing and present-but- > zero *cells properties since commit e42ee61017f5 ("of: Let > of_for_each_phandle fallback to non-negative cell_count"), there's no > need anymore to special case the legacy definition in > of_msi_get_domain(). > > Indeed, special casing has turned out to be harmful, because, as of > commit 7c025238b47a ("dt-bindings: irqchip: Describe the IMX MU block > as a MSI controller"), MSI controller DT bindings have started > specifying '#msi-cells' as a required property (even when the value > must be zero) as an effort to make the bindings more explicit. But, > since the special casing of 'msi-parent' only uses the existence of > '#msi-cells' for its heuristic, and not whether or not it's also > nonzero, the legacy path is not taken. Furthermore, the path to > support the new, broader definition isn't taken either since that > path has been restricted to the platform-msi bus. > > But, neither the definition of 'msi-parent' nor the definition of > '#msi-cells' is platform-msi-specific (the platform-msi bus was just > the first bus that needed '#msi-cells'), so remove both the special > casing and the restriction. The code removal also requires changing > to of_parse_phandle_with_optional_args() in order to ensure the > legacy (but compatible) use of 'msi-parent' remains supported. This > not only simplifies the code but also resolves an issue with PCI > devices finding their MSI controllers on riscv, as the riscv,imsics > binding requires '#msi-cells=<0>'. > > Signed-off-by: Andrew Jones > --- > v3: > - switch to of_for_each_phandle() to further cleanup/simplify the > code [Rob] > v2: > - switch to of_parse_phandle_with_optional_args() to ensure the > absence of #msi-cells means count=0 > > drivers/of/irq.c | 35 ++++++++--------------------------- > 1 file changed, 8 insertions(+), 27 deletions(-) > > diff --git a/drivers/of/irq.c b/drivers/of/irq.c > index c94203ce65bb..b74a3f5fc4e2 100644 > --- a/drivers/of/irq.c > +++ b/drivers/of/irq.c > @@ -709,8 +709,7 @@ struct irq_domain *of_msi_map_get_device_domain(struct device *dev, u32 id, > * @np: device node for @dev > * @token: bus type for this domain > * > - * Parse the msi-parent property (both the simple and the complex > - * versions), and returns the corresponding MSI domain. > + * Parse the msi-parent property and returns the corresponding MSI domain. > * > * Returns: the MSI domain for this device (or NULL on failure). > */ > @@ -718,33 +717,15 @@ struct irq_domain *of_msi_get_domain(struct device *dev, > struct device_node *np, > enum irq_domain_bus_token token) > { > - struct device_node *msi_np; > + struct of_phandle_iterator it; > struct irq_domain *d; > + int err; > > - /* Check for a single msi-parent property */ > - msi_np = of_parse_phandle(np, "msi-parent", 0); > - if (msi_np && !of_property_read_bool(msi_np, "#msi-cells")) { > - d = irq_find_matching_host(msi_np, token); > - if (!d) > - of_node_put(msi_np); > - return d; > - } > - > - if (token == DOMAIN_BUS_PLATFORM_MSI) { > - /* Check for the complex msi-parent version */ > - struct of_phandle_args args; > - int index = 0; > - > - while (!of_parse_phandle_with_args(np, "msi-parent", > - "#msi-cells", > - index, &args)) { > - d = irq_find_matching_host(args.np, token); > - if (d) > - return d; > - > - of_node_put(args.np); > - index++; > - } > + of_for_each_phandle(&it, err, np, "msi-parent", "#msi-cells", 0) { > + d = irq_find_matching_host(it.node, token); > + if (d) > + return d; > + of_node_put(it.node); Pretty sure the iterator does this for you. I can fixup when applying. I plan to tag for stable too. Shout if you disagree with either of these. Rob