From patchwork Sat Oct 9 10:49:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dongdong Liu X-Patchwork-Id: 12547471 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A4E4C4332F for ; Sat, 9 Oct 2021 10:52:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1460F60F6C for ; Sat, 9 Oct 2021 10:52:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231869AbhJIKyy (ORCPT ); Sat, 9 Oct 2021 06:54:54 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:24230 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232364AbhJIKyt (ORCPT ); Sat, 9 Oct 2021 06:54:49 -0400 Received: from dggeme758-chm.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4HRMLr4JrqzQj5G; Sat, 9 Oct 2021 18:51:48 +0800 (CST) Received: from SZX1000464847.huawei.com (10.21.59.169) by dggeme758-chm.china.huawei.com (10.3.19.104) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Sat, 9 Oct 2021 18:52:51 +0800 From: Dongdong Liu To: , , , , , , , CC: , Subject: [PATCH V10 4/8] PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices Date: Sat, 9 Oct 2021 18:49:34 +0800 Message-ID: <20211009104938.48225-5-liudongdong3@huawei.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20211009104938.48225-1-liudongdong3@huawei.com> References: <20211009104938.48225-1-liudongdong3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.21.59.169] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme758-chm.china.huawei.com (10.3.19.104) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org PCIe spec 5.0 r1.0 section 2.2.6.2 says: If an Endpoint supports sending Requests to other Endpoints (as opposed to host memory), the Endpoint must not send 10-Bit Tag Requests to another given Endpoint unless an implementation-specific mechanism determines that the Endpoint supports 10-Bit Tag Completer capability. Add a 10bit_tag sysfs file, write 0 to disable 10-Bit Tag Requester when the driver does not bind the device. The typical use case is for p2pdma when the peer device does not support 10-Bit Tag Completer. Write 1 to enable 10-Bit Tag Requester when RC supports 10-Bit Tag Completer capability. The typical use case is for host memory targeted by DMA Requests. The 10bit_tag file content indicate current status of 10-Bit Tag Requester Enable. Signed-off-by: Dongdong Liu --- Documentation/ABI/testing/sysfs-bus-pci | 18 +++++- drivers/pci/pci-sysfs.c | 78 +++++++++++++++++++++++++ drivers/pci/pci.h | 2 + drivers/pci/probe.c | 14 +++++ 4 files changed, 111 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index d4ae03296861..0c26346d1069 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -156,7 +156,7 @@ Description: binary file containing the Vital Product Data for the device. It should follow the VPD format defined in PCI Specification 2.1 or 2.2, but users should consider - that some devices may have incorrectly formatted data. + that some devices may have incorrectly formatted data. If the underlying VPD has a writable section then the corresponding section of this file will be writable. @@ -424,3 +424,19 @@ Description: The file is writable if the PF is bound to a driver that implements ->sriov_set_msix_vec_count(). + +What: /sys/bus/pci/devices/.../10bit_tag +Date: September 2021 +Contact: Dongdong Liu +Description: + The file will be visible when the device supports 10-Bit Tag + Requester. The file is readable, the value indicate current + status of 10-Bit Tag Requester Enable. + 1 - enabled, 0 - disabled. + + The file is also writable, write 0 to disable 10-Bit Tag + Requester when the driver does not bind the device. The typical + use case is for p2pdma when the peer device does not support + 10-Bit Tag Completer. Write 1 to enable 10-Bit Tag Requester + when RC supports 10-Bit Tag Completer capability. The typical + use case is for host memory targeted by DMA Requests. diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 7fb5cd17cc98..f571e4a0eb4c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -306,6 +306,55 @@ static ssize_t enable_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(enable); +static ssize_t pci_10bit_tag_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pci_dev *pdev = to_pci_dev(dev); + bool enable; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (kstrtobool(buf, &enable) < 0) + return -EINVAL; + + if (pdev->driver) + return -EBUSY; + + if (!pcie_rp_10bit_tag_cmp_supported(pdev)) + return -EPERM; + + if (enable) + pcie_capability_set_word(pdev, PCI_EXP_DEVCTL2, + PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN); + else + pcie_capability_clear_word(pdev, PCI_EXP_DEVCTL2, + PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN); + + return count; +} + +static ssize_t pci_10bit_tag_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct pci_dev *pdev = to_pci_dev(dev); + u16 ctl; + int ret; + + ret = pcie_capability_read_word(pdev, PCI_EXP_DEVCTL2, &ctl); + if (ret) + return -EINVAL; + + return sysfs_emit(buf, "%u\n", + !!(ctl & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN)); +} + +static struct device_attribute dev_attr_10bit_tag = __ATTR(10bit_tag, 0644, + pci_10bit_tag_show, + pci_10bit_tag_store); + #ifdef CONFIG_NUMA static ssize_t numa_node_store(struct device *dev, struct device_attribute *attr, const char *buf, @@ -635,6 +684,11 @@ static struct attribute *pcie_dev_attrs[] = { NULL, }; +static struct attribute *pcie_dev_10bit_tag_attrs[] = { + &dev_attr_10bit_tag.attr, + NULL, +}; + static struct attribute *pcibus_attrs[] = { &dev_attr_bus_rescan.attr, &dev_attr_cpuaffinity.attr, @@ -1482,6 +1536,24 @@ static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj, return 0; } +static umode_t pcie_dev_10bit_tag_attrs_is_visible(struct kobject *kobj, + struct attribute *a, int n) +{ + struct device *dev = kobj_to_dev(kobj); + struct pci_dev *pdev = to_pci_dev(dev); + + if (pdev->is_virtfn) + return 0; + + if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ENDPOINT) + return 0; + + if (!(pdev->devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_REQ)) + return 0; + + return a->mode; +} + static const struct attribute_group pci_dev_group = { .attrs = pci_dev_attrs, }; @@ -1522,6 +1594,11 @@ static const struct attribute_group pcie_dev_attr_group = { .is_visible = pcie_dev_attrs_are_visible, }; +static const struct attribute_group pcie_dev_10bit_tag_attr_group = { + .attrs = pcie_dev_10bit_tag_attrs, + .is_visible = pcie_dev_10bit_tag_attrs_is_visible, +}; + static const struct attribute_group *pci_dev_attr_groups[] = { &pci_dev_attr_group, &pci_dev_hp_attr_group, @@ -1531,6 +1608,7 @@ static const struct attribute_group *pci_dev_attr_groups[] = { #endif &pci_bridge_attr_group, &pcie_dev_attr_group, + &pcie_dev_10bit_tag_attr_group, #ifdef CONFIG_PCIEAER &aer_stats_attr_group, #endif diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 1cce56c2aea0..f719a41dfc7f 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -264,6 +264,8 @@ struct device *pci_get_host_bridge_device(struct pci_dev *dev); void pci_put_host_bridge_device(struct device *dev); int pci_configure_extended_tags(struct pci_dev *dev, void *ign); +bool pcie_rp_10bit_tag_cmp_supported(struct pci_dev *dev); + bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, int crs_timeout); bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl, diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 7259ad774ac8..705dd4e85df5 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2042,6 +2042,20 @@ static void pci_configure_mps(struct pci_dev *dev) p_mps, mps, mpss); } +bool pcie_rp_10bit_tag_cmp_supported(struct pci_dev *dev) +{ + struct pci_dev *root; + + root = pcie_find_root_port(dev); + if (!root) + return false; + + if (!(root->devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP)) + return false; + + return true; +} + int pci_configure_extended_tags(struct pci_dev *dev, void *ign) { struct pci_host_bridge *host;