From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BC16B78289; Thu, 3 Oct 2024 10:31:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727951471; cv=none; b=g2RUo0ypY9VcW8d/dRHOYzkId5POQEIeqO8tT2zy2P3+Y1B1ko1YvYCwRkPEaws8v5gGuFL/F88f7YsobvdEkuC1hYMWgyTza+Qu8QT1aYYBJ02swUpThpBqEj4G8VJlO4luqtpbbTi6TTL5sByoAeiDM+0NC3dhXysJ6oG127c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727951471; c=relaxed/simple; bh=syiU2xxnWa7hq7jVo9NrqEqzZ+mdHNHoKDzLtmQtYI0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PvCP7V9PUvHY7BFzYlt5Rq6MbR1N6yktAHifg0BJuoVn9rkbfz2LrfG+TqtmCH/GA/aDQnSja/ZVWiQYs0sG6Fy1Dk5cz+Z6828TPZ19OzQtpALo3MQqJJrGHJ5tqB/4CoJhnHzFzf82FiJ4fcDykCKm6rFteeTvVrQx6pD/iSU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A5006339; Thu, 3 Oct 2024 03:31:38 -0700 (PDT) Received: from [10.57.85.26] (unknown [10.57.85.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7C2393F64C; Thu, 3 Oct 2024 03:31:03 -0700 (PDT) Message-ID: Date: Thu, 3 Oct 2024 11:30:58 +0100 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] PCI: Add enable_device() and disable_device() callbacks for bridges To: Frank Li , Bjorn Helgaas , Richard Zhu , Lucas Stach , Lorenzo Pieralisi , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Manivannan Sadhasivam , Rob Herring , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev, alyssa@rosenzweig.io, bpf@vger.kernel.org, broonie@kernel.org, jgg@ziepe.ca, joro@8bytes.org, lgirdwood@gmail.com, maz@kernel.org, p.zabel@pengutronix.de, will@kernel.org References: <20240930-imx95_lut-v2-0-3b6467ba539a@nxp.com> <20240930-imx95_lut-v2-1-3b6467ba539a@nxp.com> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20240930-imx95_lut-v2-1-3b6467ba539a@nxp.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024-09-30 8:42 pm, Frank Li wrote: > Some PCIe bridges require special handling when enabling or disabling > PCIe devices. For example, on the i.MX95 platform, a lookup table must be > configured to inform the hardware how to convert pci_device_id to stream > (bus master) ID, which is used by the IOMMU and MSI controller to identify > bus master device. > > Enablement will be failure when there is not enough lookup table resource. > Avoid DMA write to wrong position. That is the reason why pci_fixup_enable > can't work since not return value for fixup function. > > Signed-off-by: Frank Li > --- > Change from v1 to v2 > - move enable(disable)device ops to pci_host_bridge > --- > drivers/pci/pci.c | 14 ++++++++++++++ > include/linux/pci.h | 2 ++ > 2 files changed, 16 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 7d85c04fbba2a..fcdeb12622568 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2056,6 +2056,7 @@ int __weak pcibios_enable_device(struct pci_dev *dev, int bars) > static int do_pci_enable_device(struct pci_dev *dev, int bars) > { > int err; > + struct pci_host_bridge *host_bridge; > struct pci_dev *bridge; > u16 cmd; > u8 pin; > @@ -2068,6 +2069,13 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars) > if (bridge) > pcie_aspm_powersave_config_link(bridge); > > + host_bridge = pci_find_host_bridge(dev->bus); > + if (host_bridge && host_bridge->enable_device) { > + err = host_bridge->enable_device(host_bridge, dev); If the intent is that this call may allocate host bridge resources, what about the existing error returns below? Should those now have a cleanup path to avoid a potential resource leak from here? Thanks, Robin. > + if (err) > + return err; > + } > + > err = pcibios_enable_device(dev, bars); > if (err < 0) > return err; > @@ -2262,12 +2270,18 @@ void pci_disable_enabled_device(struct pci_dev *dev) > */ > void pci_disable_device(struct pci_dev *dev) > { > + struct pci_host_bridge *host_bridge; > + > dev_WARN_ONCE(&dev->dev, atomic_read(&dev->enable_cnt) <= 0, > "disabling already-disabled device"); > > if (atomic_dec_return(&dev->enable_cnt) != 0) > return; > > + host_bridge = pci_find_host_bridge(dev->bus); > + if (host_bridge && host_bridge->disable_device) > + host_bridge->disable_device(host_bridge, dev); > + > do_pci_disable_device(dev); > > dev->is_busmaster = 0; > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 573b4c4c2be61..ac15b02e14ddd 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -578,6 +578,8 @@ struct pci_host_bridge { > u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */ > int (*map_irq)(const struct pci_dev *, u8, u8); > void (*release_fn)(struct pci_host_bridge *); > + int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); > + void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); > void *release_data; > unsigned int ignore_reset_delay:1; /* For entire hierarchy */ > unsigned int no_ext_tags:1; /* No Extended Tags */ >