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 6C14BCEE350 for ; Tue, 18 Nov 2025 20:06:32 +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:References: 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: List-Owner; bh=Z+p3aNRhdeRp/QNqlh+IWdh6IAAyLnO0jerVShLL8FM=; b=Kc1XFvOVVocwTU P6NwcGsH4aUV1/nSjipNMulJd4hDrbnmcCC0ugfaA/EvTQ6OB1juSKVb3IqJyFy/rY73NsQMzze43 yCcigLhTMLACKmggQJ0OzQZxAoNz2vW/mHhguN4UHw4GoI7jgxe+ysvMJezcy6+kLrVc8ytxWnoDk 3RzRqXZ5s08/QyBLId+IeuIe+ArSNkT5hnWuztoQj+N9Ac93Fo1/HJ6JG2eZnWw/FBZtNMvTNlNgl iYO2Qpmpbtr5JrC39GB85IiyQaxjynG/Sm1AKQ3eWrE3hcujvn3dKWjN7jZh/7VLT9T6UeQaWXwgt pRabJ6eFWQGxcNvFlgsQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLRy3-000000013XI-2zWy; Tue, 18 Nov 2025 20:06:23 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLRy1-000000013Wn-1c4b; Tue, 18 Nov 2025 20:06:22 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 2AABD40ADA; Tue, 18 Nov 2025 20:06:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF55DC4CEF5; Tue, 18 Nov 2025 20:06:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763496378; bh=OWueXLv1GkidpSobbWOxzP1bNyno7+0tNkEr7FL03sw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kUurIK0Z0sKXeHJdsUgGZ2LIf1F7YrKZt2nQRR4Isz709nmFMo/qoMDiEkAtB0a0q qiccU3CYAvBKFHEkPzn4DND9yaXDM9f9Q3No5h2j1xvWeMjaE3cD7XKzlhTVNLIVF5 LsMX1t/AS2eJNIE704QaNBpZSI559hShgvQ/QPMUMqpCpsxEhDFqNT7XShwrd2NWrj l8IDJLQhluW8axVX9tzEZ4A/bHphXCNCkjM2T5PLydmqgMVCGYs55/f/NhT9fC7rUk Gn+NggMtGQLfqe24VnT0aic3x1CFUnLoIY6e97PtARFNVHdy+tVjrmBZkpGLAYtoiP B0mkVjNKqwvCA== Date: Tue, 18 Nov 2025 21:06:08 +0100 From: Niklas Cassel To: Bjorn Helgaas Cc: Shawn Lin , Manivannan Sadhasivam , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Heiko Stuebner , Kever Yang , Simon Xue , Damien Le Moal , Dragan Simic , FUKAUMI Naoki , Diederik de Haas , Richard Zhu , Frank Li , Lucas Stach , Shawn Guo , Sascha Hauer , Fabio Estevam , Conor Dooley , Krzysztof Kozlowski , Thierry Reding , Jonathan Hunter , Hans Zhang , linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, kernel@pengutronix.de, Bjorn Helgaas Subject: Re: [PATCH 2/4] PCI: tegra194: Remove unnecessary L1SS disable code Message-ID: References: <20251118185917.GA2583698@bhelgaas> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20251118185917.GA2583698@bhelgaas> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251118_120621_490415_86630E84 X-CRM114-Status: GOOD ( 24.63 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On Tue, Nov 18, 2025 at 12:59:17PM -0600, Bjorn Helgaas wrote: > On Wed, Nov 12, 2025 at 09:29:20AM +0100, Niklas Cassel wrote: > > On Tue, Nov 11, 2025 at 04:16:09PM -0600, Bjorn Helgaas wrote: > > > From: Bjorn Helgaas > > > > > > The DWC core clears the L1 Substates Supported bits unless the driver sets > > > the "dw_pcie.l1ss_support" flag. > > > > > > The tegra194 init_host_aspm() sets "dw_pcie.l1ss_support" if the platform > > > has the "supports-clkreq" DT property. If "supports-clkreq" is absent, > > > "dw_pcie.l1ss_support" is not set, and the DWC core will clear the L1 > > > Substates Supported bits. > > > > > > The tegra194 code to clear the L1 Substates Supported bits is unnecessary, > > > so remove it. > > > > > > Signed-off-by: Bjorn Helgaas > > > --- > > > > Since init_host_aspm() is now the only place using struct tegra_pcie_dw > > struct member cfg_link_cap_l1sub, I think that you can remove this struct > > member, and instead make this a local variable in init_host_aspm(). > > It looks like tegra_pcie_ep_irq_thread() also uses it, although I'm > dubious about that. > > It's odd that software would be responsible for sending LTR messages, > but I guess this only happens for tegra194_pcie_dw_ep_of_data, and > apparently it's fixed (".has_ltr_req_fix" for tegra234. > > And odd that we would read the capability register on every interrupt > even though this driver is the only thing that can change it, so we > should be able to cache the value in init_host_aspm(). Yes, sorry, my thinking was that this code in tegra_pcie_ep_irq_thread(): /* If EP doesn't advertise L1SS, just return */ val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub); if (!(val & (PCI_L1SS_CAP_ASPM_L1_1 | PCI_L1SS_CAP_ASPM_L1_2))) return IRQ_HANDLED; after your patch can be replaced with: /* If EP doesn't advertise L1SS, just return */ if (!pci->l1ss_support) return IRQ_HANDLED; Since we already know that if !pci->l1ss_support, these bits will be cleared by DWC common code. So, after that, we could replace the struct tegra_pcie_dw struct member cfg_link_cap_l1sub with a local variable in init_host_aspm(). Kind regards, Niklas _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip