From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7295614F9C6; Fri, 12 Apr 2024 20:22:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712953338; cv=none; b=rD+7R/cTcxggeN7Awxc9EjklxDZVOtT0hKxrXgtD8ZXwlp4HYkyv4rNUjoGYq0LmcH/bRF4/D4Bnl0rGcarv509W4ie82iVObDbAOW9B0XgnkYR1t3wWMCMjHskqx3XdlVa5GFRZXKvf+5ud21ooNu1pXMoQavpa4qqI5dCxC54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712953338; c=relaxed/simple; bh=sn2OmynqMr6J7esZV94bEU0Yo+Dr7urRItKlgNXXkk8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=qhh+DVzwfvS1HMMy8VucMrmyNMPMbNMtnFnDrb2d2Auc/7qKpJ3fL2Oj8fkgMv2GmcoIn+KbmYz7B9d/r3WaFNzNwkGA8FHov+iv55PmjED/boSTRTexFMl3QSAo6BDO9qDBCUIsmTY+nQPIeT2dDcsIVjXNwASA39EblkdidJ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mBBFqL53; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mBBFqL53" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3A70C113CC; Fri, 12 Apr 2024 20:22:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712953338; bh=sn2OmynqMr6J7esZV94bEU0Yo+Dr7urRItKlgNXXkk8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=mBBFqL53k8d8ZRiCErYU+z9y7mNs9HHDllT10pZ3ClqXZjEuN0B8ebU0XrYAbSEpa QIQCzjz9kSUPV2Gm101R8qF0Fzm/d2ECYeTqOYdngkP0oFGR/IEq1gIF5QqZJLwFLh FwyDBuniceg4diUmqI1tezD9L6IV7P6ymG4dV/PcGZyQNp9isKFZpILhe3DRxFroRZ kl6wGt76+5I0oZFe7K9D9ea7a2c8J3M7XvW75EVELJ4xyJA6ycIRtQUiukrwLyTuh2 Hbb4UXqrYyQamtx23jHin0qc0HsDUuz6DG1NpfKAu+Ky81T3wDDvRZtoadLACzqpGp 0K71g/atBsARQ== Date: Fri, 12 Apr 2024 15:22:16 -0500 From: Bjorn Helgaas To: Manivannan Sadhasivam Cc: Jingoo Han , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , Marek Vasut , Yoshihiro Shimoda , Thierry Reding , Jonathan Hunter , Vidya Sagar , Vignesh Raghavendra , Richard Zhu , Lucas Stach , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Minghuan Lian , Mingkai Hu , Roy Zang , Kunihiko Hayashi , Masami Hiramatsu , Kishon Vijay Abraham I , Jesper Nilsson , Srikanth Thokala , Shawn Lin , Heiko Stuebner , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Niklas Cassel , linux-arm-kernel@axis.com, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v12 8/8] PCI: endpoint: Remove "core_init_notifier" flag Message-ID: <20240412202216.GA14590@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240327-pci-dbi-rework-v12-8-082625472414@linaro.org> On Wed, Mar 27, 2024 at 02:43:37PM +0530, Manivannan Sadhasivam wrote: > "core_init_notifier" flag is set by the glue drivers requiring refclk from > the host to complete the DWC core initialization. Also, those drivers will > send a notification to the EPF drivers once the initialization is fully > completed using the pci_epc_init_notify() API. Only then, the EPF drivers > will start functioning. > > For the rest of the drivers generating refclk locally, EPF drivers will > start functioning post binding with them. EPF drivers rely on the > 'core_init_notifier' flag to differentiate between the drivers. > Unfortunately, this creates two different flows for the EPF drivers. > > So to avoid that, let's get rid of the "core_init_notifier" flag and follow > a single initialization flow for the EPF drivers. This is done by calling > the dw_pcie_ep_init_notify() from all glue drivers after the completion of > dw_pcie_ep_init_registers() API. This will allow all the glue drivers to > send the notification to the EPF drivers once the initialization is fully > completed. Thanks for doing this! I think this is a significantly nicer solution than core_init_notifier was. One question: both qcom and tegra194 call dw_pcie_ep_init_registers() from an interrupt handler, but they register that handler in a different order with respect to dw_pcie_ep_init(). I don't know what actually starts the process that leads to the interrupt, but if it's dw_pcie_ep_init(), then one of these (qcom, I think) must be racy: qcom_pcie_ep_probe dw_pcie_ep_init <- A qcom_pcie_ep_enable_irq_resources devm_request_threaded_irq(qcom_pcie_ep_perst_irq_thread) <- B qcom_pcie_ep_perst_irq_thread qcom_pcie_perst_deassert dw_pcie_ep_init_registers tegra_pcie_dw_probe tegra_pcie_config_ep devm_request_threaded_irq(tegra_pcie_ep_pex_rst_irq) <- B dw_pcie_ep_init <- A tegra_pcie_ep_pex_rst_irq pex_ep_event_pex_rst_deassert dw_pcie_ep_init_registers Whatever the right answer is, I think qcom and tegra194 should both order dw_pcie_ep_init() and the devm_request_threaded_irq() the same way. Bjorn