From patchwork Fri Mar 12 17:34:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amey Narkhede X-Patchwork-Id: 1452250 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=RF1TURJa; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DxtLs29wSz9sRR for ; Sat, 13 Mar 2021 04:37:57 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232836AbhCLRhY (ORCPT ); Fri, 12 Mar 2021 12:37:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232057AbhCLRgy (ORCPT ); Fri, 12 Mar 2021 12:36:54 -0500 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBDE9C061761; Fri, 12 Mar 2021 09:36:53 -0800 (PST) Received: by mail-pj1-x1030.google.com with SMTP id lr10-20020a17090b4b8ab02900dd61b95c5eso8813967pjb.4; Fri, 12 Mar 2021 09:36:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Zjhsutfaeg2zNXMNMCFjuL9SYJCyEz5Q4XqI1wTv0Ik=; b=RF1TURJaNG+GldM5/SQ5joAXkkFNDBuM6+XdowZkvodau/rvsnvyF73wAIafTxZqBO 8rC+JnPWv17QtUrQTGLCn5KLUGMBbaCI16q2z8FcQyOi38KYGJcUmvLPZpz/dOnb2+RW c3/+v1daRTRlp1Ox1h+BdTUvcQmo6Iv1Dr+ifqoiyAzlE4EhPFos6ippfrB8U5D2Rtuz I0fgFtnbj0JB0mkreB86chsonVUecAX97iELeurqJxxfzgRBtgPUQLS+GBqQnBS4e3g3 ZvQKSejG9CkqckJb6TieLKtyZshMR7rjLwpTIs3YUqMxQTTXnnNH82TAbPDCno1IsKA/ Pybg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Zjhsutfaeg2zNXMNMCFjuL9SYJCyEz5Q4XqI1wTv0Ik=; b=tyNOzVNOkLeD0HjB0A8zDsnbdAiLmVX6hQU0Zm4LGrhEiaNVfAZ2ag8jQBqGCf4not YN/ny77HI/yJldm4X6bGibUDhoNOJF/020YyL5qBnf2OQSm8whuarGYghPEdYcgZi+KU XIivJ2J3s9H8YIWCWL1RF3bKBXsppWUdQZzSk6C0gYDTVUTB2Tbs8nbyR9BhKuBraZ/Y Svk4Y3Yuvr0lOAdpEOwPq/emzX3FAdopptTs5MiJnhEq2/AHZqH+oDUeNzfgEUxA2V+T wOigJKxq667im9zbd0yPkbXMcU+XuXeVSAgmfeuPgDSn/iCWBWBdyt0OBfEzmRgo6voi KYzA== X-Gm-Message-State: AOAM533euhx0kCk7KG86tWKIlHqq4FKZXcNW8pWTwSprdTCICW4eRh9G RRfKu/ts5uEfmvtK34HBvuE= X-Google-Smtp-Source: ABdhPJxTH/NXED/lfZqHjFsm4/PGtY8ZKPZbRVS/szN/fl0IfyyToFyhfbcnYUS3XB1iCAI5DPxfKg== X-Received: by 2002:a17:902:7444:b029:e4:30bf:8184 with SMTP id e4-20020a1709027444b02900e430bf8184mr115558plt.45.1615570613463; Fri, 12 Mar 2021 09:36:53 -0800 (PST) Received: from localhost.localdomain ([103.248.31.144]) by smtp.googlemail.com with ESMTPSA id l10sm180045pfc.125.2021.03.12.09.36.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Mar 2021 09:36:53 -0800 (PST) From: ameynarkhede03@gmail.com To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, raphael.norwitz@nutanix.com, Amey Narkhede Subject: [PATCH 4/4] PCI/sysfs: Allow userspace to query and set device reset mechanism Date: Fri, 12 Mar 2021 23:04:52 +0530 Message-Id: <20210312173452.3855-5-ameynarkhede03@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210312173452.3855-1-ameynarkhede03@gmail.com> References: <20210312173452.3855-1-ameynarkhede03@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Amey Narkhede Add reset_methods_enabled bitmap to struct pci_dev to keep track of user preferred device reset mechanisms. Add reset_method sysfs attribute to query and set user preferred device reset mechanisms. Signed-off-by: Amey Narkhede --- Reviewed-by: Alex Williamson Reviewed-by: Raphael Norwitz Documentation/ABI/testing/sysfs-bus-pci | 15 ++++++ drivers/pci/pci-sysfs.c | 66 +++++++++++++++++++++++-- drivers/pci/pci.c | 3 +- include/linux/pci.h | 2 + 4 files changed, 82 insertions(+), 4 deletions(-) -- 2.30.2 diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 25c9c3977..ae53ecd2e 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -121,6 +121,21 @@ Description: child buses, and re-discover devices removed earlier from this part of the device tree. +What: /sys/bus/pci/devices/.../reset_method +Date: March 2021 +Contact: Amey Narkhede +Description: + Some devices allow an individual function to be reset + without affecting other functions in the same slot. + For devices that have this support, a file named reset_method + will be present in sysfs. Reading this file will give names + of the device supported reset methods. Currently used methods + are enclosed in brackets. Writing the name of any of the device + supported reset method to this file will set the reset method to + be used when resetting the device. Writing "none" to this file + will disable ability to reset the device and writing "default" + will return to the original value. + What: /sys/bus/pci/devices/.../reset Date: July 2009 Contact: Michael S. Tsirkin diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 78d2c130c..3cd06d1c0 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1304,6 +1304,59 @@ static const struct bin_attribute pcie_config_attr = { .write = pci_write_config, }; +static ssize_t reset_method_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + const struct pci_reset_fn_method *reset; + struct pci_dev *pdev = to_pci_dev(dev); + ssize_t len = 0; + int i; + + for (i = 0, reset = pci_reset_fn_methods; reset->reset_fn; i++, reset++) { + if (pdev->reset_methods_enabled & (1 << i)) + len += sysfs_emit_at(buf, len, "[%s] ", reset->name); + else if (pdev->reset_methods & (1 << i)) + len += sysfs_emit_at(buf, len, "%s ", reset->name); + } + + return len; +} + +static ssize_t reset_method_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + const struct pci_reset_fn_method *reset = pci_reset_fn_methods; + struct pci_dev *pdev = to_pci_dev(dev); + u8 reset_mechanism; + int i = 0; + + /* Writing none disables reset */ + if (sysfs_streq(buf, "none")) { + reset_mechanism = 0; + } else if (sysfs_streq(buf, "default")) { + /* Writing default returns to initial value */ + reset_mechanism = pdev->reset_methods; + } else { + reset_mechanism = 0; + for (; reset->reset_fn; i++, reset++) { + if (sysfs_streq(buf, reset->name)) { + reset_mechanism = 1 << i; + break; + } + } + if (!reset_mechanism || !(pdev->reset_methods & reset_mechanism)) + return -EINVAL; + } + + pdev->reset_methods_enabled = reset_mechanism; + + return count; +} + +static DEVICE_ATTR_RW(reset_method); + static ssize_t reset_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -1337,11 +1390,16 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev) if (dev->reset_methods) { retval = device_create_file(&dev->dev, &dev_attr_reset); if (retval) - goto error; + goto err_reset; + retval = device_create_file(&dev->dev, &dev_attr_reset_method); + if (retval) + goto err_method; } return 0; -error: +err_method: + device_remove_file(&dev->dev, &dev_attr_reset); +err_reset: pcie_vpd_remove_sysfs_dev_files(dev); return retval; } @@ -1417,8 +1475,10 @@ int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev) static void pci_remove_capabilities_sysfs(struct pci_dev *dev) { pcie_vpd_remove_sysfs_dev_files(dev); - if (dev->reset_methods) + if (dev->reset_methods) { device_remove_file(&dev->dev, &dev_attr_reset); + device_remove_file(&dev->dev, &dev_attr_reset_method); + } } /** diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b7f6c6588..81cebea56 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5106,7 +5106,7 @@ int __pci_reset_function_locked(struct pci_dev *dev) might_sleep(); for (i = 0, reset = pci_reset_fn_methods; reset->reset_fn; i++, reset++) { - if (!(dev->reset_methods & (1 << i))) + if (!(dev->reset_methods_enabled & (1 << i))) continue; /* @@ -5153,6 +5153,7 @@ void pci_init_reset_methods(struct pci_dev *dev) else if (rc != -ENOTTY) break; } + dev->reset_methods_enabled = dev->reset_methods; } /** diff --git a/include/linux/pci.h b/include/linux/pci.h index a2f003f4e..400f614e0 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -335,6 +335,8 @@ struct pci_dev { * See pci_reset_fn_methods array in pci.c */ u8 __bitwise reset_methods; /* bitmap for device supported reset capabilities */ + /* bitmap for user enabled and device supported reset capabilities */ + u8 __bitwise reset_methods_enabled; #ifdef CONFIG_PCIEAER u16 aer_cap; /* AER capability offset */ struct aer_stats *aer_stats; /* AER stats for this device */