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 5A46F237EA9; Wed, 4 Dec 2024 17:13:51 +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=1733332431; cv=none; b=UAS6JTg0+AlCh7h2Wxqouq3CT5q79RWGxpUbAHWvEwkEi2TdCU8cVVe79VZi02vlCHNocVaKYv9L8Tnv+0dvq30A0ekDsRkIXFlkxbhgy2a7DZ7Pmt56rikC2+Hpc0okisio9UcOprpaBu7e7oF9zoQh8B3RqEDRaMGIxuRnNtk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733332431; c=relaxed/simple; bh=8M/Jum5fWN8HQfQEjzcs3WHILNDZXYw63L8S27jfc1k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gC/S1Hoi0Zj9J/JEb95/er2brbSwoUcuXf0ctAVtePeO6IFPp4uo2B9eb8IdfBeDF96JctfueN/bK55sYM71XiFk16pPpXuodTgHOWoVcP53qDqNrnIY4/Sj3sW3nUCBeCW7f4AUoSb/JfylGs9Y7Ar5vjJcqNiCjiwIM++thDE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vcjvr3iw; 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="Vcjvr3iw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8460C4CECD; Wed, 4 Dec 2024 17:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733332430; bh=8M/Jum5fWN8HQfQEjzcs3WHILNDZXYw63L8S27jfc1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vcjvr3iwoJK2OtfkovHJQeDKkrwKwC1O3S/519oKN54dBGIBfJEbRszM+oBqB+0By ueuDMu7OWJwnYHcV2ZMfvKYM3ECa2HO5QNa+w917BmwROtzg2arH85TFShTZsYTz0r 9ouLzSonA8PxOqHX2mVVYk+EtV1rBPjrwHPVIqF5MwHOZ0eb99/NFN6jH0k7Ihq9dZ vpG+G0vKCeMN3VJv4nkuYP9Px82i5G8Ur8SG4UjTcr2Qbk4yau64pz3n8LtcZ3xvab OJzpVkLhYTwGfRJQY1vS+LwOH7wmP9hFDi6eL2Zte3mp09hwaCe37gL2KtvaGWom41 yVU9L2q9wLWOQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Keith Busch , Bjorn Helgaas , Alex Williamson , Amey Narkhede , Sasha Levin , ilpo.jarvinen@linux.intel.com, mariusz.tkaczyk@linux.intel.com, stuart.w.hayes@gmail.com, linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 2/4] PCI: Add 'reset_subordinate' to reset hierarchy below bridge Date: Wed, 4 Dec 2024 11:02:23 -0500 Message-ID: <20241204160227.2217428-2-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241204160227.2217428-1-sashal@kernel.org> References: <20241204160227.2217428-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.286 Content-Transfer-Encoding: 8bit From: Keith Busch [ Upstream commit 2fa046449a82a7d0f6d9721dd83e348816038444 ] The "bus" and "cxl_bus" reset methods reset a device by asserting Secondary Bus Reset on the bridge leading to the device. These only work if the device is the only device below the bridge. Add a sysfs 'reset_subordinate' attribute on bridges that can assert Secondary Bus Reset regardless of how many devices are below the bridge. This resets all the devices below a bridge in a single command, including the locking and config space save/restore that reset methods normally do. This may be the only way to reset devices that don't support other reset methods (ACPI, FLR, PM reset, etc). Link: https://lore.kernel.org/r/20241025222755.3756162-1-kbusch@meta.com Signed-off-by: Keith Busch [bhelgaas: commit log, add capable(CAP_SYS_ADMIN) check] Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson Reviewed-by: Amey Narkhede Signed-off-by: Sasha Levin --- Documentation/ABI/testing/sysfs-bus-pci | 11 +++++++++++ drivers/pci/pci-sysfs.c | 26 +++++++++++++++++++++++++ drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 1 + 4 files changed, 39 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 8bfee557e50ea..e84434d48dcf0 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -125,6 +125,17 @@ Description: will be present in sysfs. Writing 1 to this file will perform reset. +What: /sys/bus/pci/devices/.../reset_subordinate +Date: October 2024 +Contact: linux-pci@vger.kernel.org +Description: + This is visible only for bridge devices. If you want to reset + all devices attached through the subordinate bus of a specific + bridge device, writing 1 to this will try to do it. This will + affect all devices attached to the system through this bridge + similiar to writing 1 to their individual "reset" file, so use + with caution. + What: /sys/bus/pci/devices/.../vpd Date: February 2008 Contact: Ben Hutchings diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 90d5a29a6ff3d..131c6d7e86f8f 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -505,6 +505,31 @@ static ssize_t bus_rescan_store(struct device *dev, static struct device_attribute dev_attr_bus_rescan = __ATTR(rescan, 0200, NULL, bus_rescan_store); +static ssize_t reset_subordinate_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct pci_bus *bus = pdev->subordinate; + unsigned long val; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (kstrtoul(buf, 0, &val) < 0) + return -EINVAL; + + if (val) { + int ret = __pci_reset_bus(bus); + + if (ret) + return ret; + } + + return count; +} +static DEVICE_ATTR_WO(reset_subordinate); + #if defined(CONFIG_PM) && defined(CONFIG_ACPI) static ssize_t d3cold_allowed_store(struct device *dev, struct device_attribute *attr, @@ -628,6 +653,7 @@ static struct attribute *pci_dev_attrs[] = { static struct attribute *pci_bridge_attrs[] = { &dev_attr_subordinate_bus_number.attr, &dev_attr_secondary_bus_number.attr, + &dev_attr_reset_subordinate.attr, NULL, }; diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 41050a35631fa..ad5bd17f77a3b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5538,7 +5538,7 @@ EXPORT_SYMBOL_GPL(pci_probe_reset_bus); * * Same as above except return -EAGAIN if the bus cannot be locked */ -static int __pci_reset_bus(struct pci_bus *bus) +int __pci_reset_bus(struct pci_bus *bus) { int rc; diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 725d2b0d45693..7a737ef76e6de 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -41,6 +41,7 @@ int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai, int pci_probe_reset_function(struct pci_dev *dev); int pci_bridge_secondary_bus_reset(struct pci_dev *dev); int pci_bus_error_reset(struct pci_dev *dev); +int __pci_reset_bus(struct pci_bus *bus); #define PCI_PM_D2_DELAY 200 #define PCI_PM_D3_WAIT 10 -- 2.43.0