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 AE4EBC433F5 for ; Tue, 25 Jan 2022 16:58:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Owner; bh=vzu7YeeRMsf+BVjOcchkW3GUoY+YcaWLIbM9HBND1qs=; b=4cDIEoUuX23vyG VEccEoJ5Bstka5xGCVH2e8p3KdhPhK7u0LdV/bjHE6ZRgJgaB5pyj8i8q5G2GqVvEsLSwqn5+7qjX GLXwJF0JQr+H9sRIEFC1E/A6KonICtBFigIw7NMWURp1iZfcG8SGeqzPeGXqy1xmzcyrM5UK4tGNu hMsLZyb45h/J5UAvy40sgkc9kxYNQcTPkOoXUTiCy5q/pz8ZtbjX/PjbT3TKXO3pYH4QaGyyfnvdw 5v3Zxpte1GWy1VaxsWiIjHehTAwydOGgj4uoufkfLyWr6lAmnIF7bQPPUttB9lEba9Ebl+rx+3Zmy mCzAGfOzPrJDnw1tGK8g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nCP8y-008ogf-2M; Tue, 25 Jan 2022 16:58:08 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nCP8i-008oc3-9v; Tue, 25 Jan 2022 16:57:54 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0365AB81912; Tue, 25 Jan 2022 16:57:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D488C340E0; Tue, 25 Jan 2022 16:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643129869; bh=6XkwXgsw19qj7USLrufn0h/tjB7gak8V19SNDIbm7V8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=LJ678dooB3UE1J+39GaMMyngBcQRH9jk6vt/5V1WPObw1WTcNf87X/MvOI02+KCsk ZSGZbwVHwrnXd5ybU5Caxd0VIqT6wHtu7sshlroYRQHKp1zinrqKA6QIUZMONlsOrH jxPNE1B1lqteRYJ0ePeUInqCQs0p0uuITFc37fJlRN87P+q8s1W2GGk3UN8SgYxxkI S/f4p1PTvgTGq/tpMhI6MHdjFZi5QsIq3xkZKXNJ+B+yFExbGB1F3PC+AL+jJO0Nl8 QGkStm965gjNBUgErdUUe00An9cLRjJYjawdvvi79/WnvnMXB+in8AV0A9yVPGpsVR hCtO/WYvAK7DQ== Date: Tue, 25 Jan 2022 10:57:48 -0600 From: Bjorn Helgaas To: qizhong cheng Cc: Ryder Lee , Jianjun Wang , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, chuanjia.liu@mediatek.com Subject: Re: [PATCH] PCI: mediatek: Change MSI interrupt processing sequence Message-ID: <20220125165748.GA1458116@bhelgaas> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220123033306.29799-1-qizhong.cheng@mediatek.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220125_085752_512876_473CFA84 X-CRM114-Status: GOOD ( 21.14 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org All patches change *something*. Can you update the subject line so it says something specific about the change? Maybe something like "Clear MSI status before dispatching handler"? On Sun, Jan 23, 2022 at 11:33:06AM +0800, qizhong cheng wrote: > As an edge-triggered interrupts, its interrupt status should be cleared > before dispatch to the handler of device. I'm not an IRQ expert, but the reasoning that "we should clear the MSI interrupt status before dispatching the handler because MSI is an edge-triggered interrupt" doesn't seem completely convincing because your code will now look like this: /* Clear the INTx */ writel(1 << bit, port->base + PCIE_INT_STATUS); generic_handle_domain_irq(port->irq_domain, bit - INTX_SHIFT); ... /* Clear MSI interrupt status */ writel(MSI_STATUS, port->base + PCIE_INT_STATUS); generic_handle_domain_irq(port->inner_domain, bit); You clear interrupt status before dispatching the handler for *both* level-triggered INTx interrupts and edge-triggered MSI interrupts. So it doesn't seem that simply being edge-triggered is the critical factor here. > Signed-off-by: qizhong cheng > --- > drivers/pci/controller/pcie-mediatek.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > index 2f3f974977a3..705ea33758b1 100644 > --- a/drivers/pci/controller/pcie-mediatek.c > +++ b/drivers/pci/controller/pcie-mediatek.c > @@ -624,12 +624,12 @@ static void mtk_pcie_intr_handler(struct irq_desc *desc) > if (status & MSI_STATUS){ > unsigned long imsi_status; > > + /* Clear MSI interrupt status */ > + writel(MSI_STATUS, port->base + PCIE_INT_STATUS); > while ((imsi_status = readl(port->base + PCIE_IMSI_STATUS))) { > for_each_set_bit(bit, &imsi_status, MTK_MSI_IRQS_NUM) > generic_handle_domain_irq(port->inner_domain, bit); > } > - /* Clear MSI interrupt status */ > - writel(MSI_STATUS, port->base + PCIE_INT_STATUS); > } > } > > -- > 2.25.1 > > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-mediatek _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek