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Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLSDP-000000014MR-2Mtk; Tue, 18 Nov 2025 20:22:15 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLSDO-000000014Lr-1iG0; Tue, 18 Nov 2025 20:22:14 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 7D4E0601B0; Tue, 18 Nov 2025 20:22:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9819DC2BC86; Tue, 18 Nov 2025 20:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763497333; bh=m/y5HsGDFoNmN0W5o2ZWtHNb/BQMArPMLKv4Hr2h3S8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=CMrjatDwWqdM/v1dfj1rdQS5VbA8KTQeF2MCab2sKZ+pRRyFCtoXrwdXRWP/MXJWb e2YL4Z9l8u4EMzOLcmz95mCYQJwYpOaExEL3/aF1iyxGNrbGwOdnq/v+TJ0wawd8Br 60iotRVM03mtDzt6h01lahKDWUrBddEOgZru4vSf6Zuc6o8glHkqkIWb2cRA8Q1qdA WQtnOsFvOWYnZMMenGPUjUISmMbm4yMlBPp2M0frhiOpea+0EKQLY/5DnMxqPewZPp 6F4QjGFzap+UESXlGdEOIK1E69TzlX5xOcyFcsqbBwramyit9tpnxvgkZ9DJGJ/Umw 2vfGPd/xT6S/Q== Date: Tue, 18 Nov 2025 14:22:10 -0600 From: Bjorn Helgaas To: Manivannan Sadhasivam Cc: Niklas Cassel , Shawn Lin , 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 1/4] PCI: dwc: Advertise L1 PM Substates only if driver requests it Message-ID: <20251118202210.GA2586610@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <22srj63j7fzmsebwxwjnnxnpmdn2iwxo36gkrl36gdm7ge2xif@dmrdbfgu3hn3> 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 Wed, Nov 12, 2025 at 11:21:07PM +0530, Manivannan Sadhasivam wrote: > On Wed, Nov 12, 2025 at 09:22:36AM +0100, Niklas Cassel wrote: > > On Tue, Nov 11, 2025 at 04:16:08PM -0600, Bjorn Helgaas wrote: > > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > > > @@ -1060,6 +1060,8 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp) > > > PCI_COMMAND_MASTER | PCI_COMMAND_SERR; > > > dw_pcie_writel_dbi(pci, PCI_COMMAND, val); > > > > > > + dw_pcie_config_l1ss(pci); > > > --- a/drivers/pci/controller/dwc/pcie-qcom.c > > > +++ b/drivers/pci/controller/dwc/pcie-qcom.c > > > @@ -1067,6 +1067,8 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie) > > > val &= ~REQ_NOT_ENTR_L1; > > > writel(val, pcie->parf + PARF_PM_CTRL); > > > > > > + pci->l1ss_support = true; > > > + > > > val = readl(pcie->parf + PARF_AXI_MSTR_WR_ADDR_HALT_V2); > > > val |= EN; > > > writel(val, pcie->parf + PARF_AXI_MSTR_WR_ADDR_HALT_V2); > > > > While it seems like ops_2_7_0 is the only type that explicitly does a > > register write to enable L1ss, other versions might have the register > > as enabled by default, so it would be nice if Mani could confirm exactly > > which versions that should set l1ss_support = true. > > > > Yes, on the rest of the platforms, this bit is supposed to be enabled by > default. AFAIK, all Qcom platforms should support L1SS, atleast the > non-IPQ/APQ ones. > > We should set it for below cfgs: > > cfg_fw_managed > cfg_sc8280xp > cfg_1_34_0 > cfg_1_9_0 > cfg_2_7_0 Except for cfg_fw_managed, the above are all covered by qcom_pcie_init_2_7_0(), either via ops_2_7_0, ops_1_9_0, or ops_1_21_0. cfg_fw_managed is harder because we don't use dw_pcie_host_init() or dw_pcie_setup_rc(). We do allocate a struct dw_pcie (where l1ss_support is) in qcom_pcie_ecam_host_init(), but only so we can call dw_pcie_msi_host_init() and dw_pcie_msi_init(). Neither of those seems like a logical place to fiddle with L1SS support. Open to suggestions. Bjorn