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Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , =?utf-8?q?Ilpo_J=C3=A4r?= =?utf-8?q?vinen?= Subject: [PATCH v7 1/8] PCI: Protect Link Control 2 Register with RMW locking Date: Tue, 10 Sep 2024 15:26:58 +0300 Message-Id: <20240910122705.4068-2-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 PCIe Bandwidth Controller performs RMW accesses the Link Control 2 Register which can occur concurrently to other sources of Link Control 2 Register writes. Therefore, add Link Control 2 Register among the PCI Express Capability Registers that need RMW locking. Signed-off-by: Ilpo Järvinen Reviewed-by: Lukas Wunner --- Documentation/PCI/pciebus-howto.rst | 14 +++++++++----- include/linux/pci.h | 1 + 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/Documentation/PCI/pciebus-howto.rst b/Documentation/PCI/pciebus-howto.rst index f344452651e1..375d9ce171f6 100644 --- a/Documentation/PCI/pciebus-howto.rst +++ b/Documentation/PCI/pciebus-howto.rst @@ -217,8 +217,12 @@ capability structure except the PCI Express capability structure, that is shared between many drivers including the service drivers. RMW Capability accessors (pcie_capability_clear_and_set_word(), pcie_capability_set_word(), and pcie_capability_clear_word()) protect -a selected set of PCI Express Capability Registers (Link Control -Register and Root Control Register). Any change to those registers -should be performed using RMW accessors to avoid problems due to -concurrent updates. For the up-to-date list of protected registers, -see pcie_capability_clear_and_set_word(). +a selected set of PCI Express Capability Registers: + +* Link Control Register +* Root Control Register +* Link Control 2 Register + +Any change to those registers should be performed using RMW accessors to +avoid problems due to concurrent updates. For the up-to-date list of +protected registers, see pcie_capability_clear_and_set_word(). diff --git a/include/linux/pci.h b/include/linux/pci.h index 4cf89a4b4cbc..25362d577824 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1270,6 +1270,7 @@ static inline int pcie_capability_clear_and_set_word(struct pci_dev *dev, { switch (pos) { case PCI_EXP_LNKCTL: + case PCI_EXP_LNKCTL2: case PCI_EXP_RTCTL: return pcie_capability_clear_and_set_word_locked(dev, pos, clear, set); From patchwork Tue Sep 10 12:26:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 13798408 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (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 C0077188CB1; Tue, 10 Sep 2024 12:27:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725971269; cv=none; b=OsXeLMOFSgatrE5vwKXnndLdnVdCk5ZrUE6nFpsXa+tU/e4WxMZdsyto6WysuPtl5gGm87RbvkUzlKpP9T+tV53oLtNAP8tp3Q2NcdmMUx95PhR+UyHmQC5+Ay/F3G5Hx1WhurOzcWyCDPA4BZtaiuizeEsHhVjk//ba6/Q22rI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725971269; c=relaxed/simple; bh=ut30kre0r6l6HoE6PiQwFhPgekj0Y2QkEpn/d9hdZ2k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=ZTaBHLco3ShL22XxJQDK6veM8YDSayNis/X4tMg8oLCSg7i1lFZjdiWnnKy6H459MoODPJ0fh3H5k60wMUBZrucJ8CVtgk3ErUiOZXZ69LIgATpGkYOyhWT7u5kY5KjzF29pEWRm5Y+pLceXgUSNUym17hHnvNB35twg1J5IZ8c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=AJFkpoUB; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="AJFkpoUB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1725971268; x=1757507268; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ut30kre0r6l6HoE6PiQwFhPgekj0Y2QkEpn/d9hdZ2k=; b=AJFkpoUBr2xIHSwGeLsjFMCY3syg9HFinQ7u7OvvPJUC8ENXS+z2RoZa bJkHRL5jDnkB5JlkEvk79DMZ8+mtmZ51UH+fKILuc4zSaG2ZtQWkvbLxv UbtBHoHFVyL7wFOFZ/OYAOuaOu7v1NRNmKG4TcLTkrhSLR0c5CvWkrURn sI1iqRHrqK3NaqrJJq1uSWDZK+1bWqd9o8AwgTk+nMbFZScuPfQokQRPv 2i5cyXQ9RcQvDnKgSofrmW0qLKleB2y7a0wV4Ryi7LZyRZZh9KceYTLl0 GpRtM4dtLgRaBRm4Rzxbu7G5ktm7i8WC62zNCGQNwHokKgcaG85yHan6a g==; X-CSE-ConnectionGUID: 79S3fYKqRBeFRZTeV7yh5g== X-CSE-MsgGUID: REpNjNQhS7GL6y2dyXstpQ== X-IronPort-AV: E=McAfee;i="6700,10204,11190"; a="27634268" X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="27634268" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:27:47 -0700 X-CSE-ConnectionGUID: NnTZ1qPgQSWggdq/1S9Gtg== X-CSE-MsgGUID: jHwMyIX3R7eSW+n0w4tKxA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="66968137" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.245.224]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:27:40 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , =?utf-8?q?Ilpo_J=C3=A4r?= =?utf-8?q?vinen?= Subject: [PATCH v7 2/8] PCI: Store all PCIe Supported Link Speeds Date: Tue, 10 Sep 2024 15:26:59 +0300 Message-Id: <20240910122705.4068-3-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 PCIe bandwidth controller added by a subsequent commit will require selecting PCIe Link Speeds that are lower than the Maximum Link Speed. The struct pci_bus only stores max_bus_speed. Even if PCIe r6.1 sec 8.2.1 currently disallows gaps in supported Link Speeds, the Implementation Note in PCIe r6.1 sec 7.5.3.18, recommends determining supported Link Speeds using the Supported Link Speeds Vector in the Link Capabilities 2 Register (when available) to "avoid software being confused if a future specification defines Links that do not require support for all slower speeds." Reuse code in pcie_get_speed_cap() to add pcie_get_supported_speeds() to query the Supported Link Speeds Vector of a PCIe device. The value is taken directly from the Supported Link Speeds Vector or synthetized from the Max Link Speed in the Link Capabilities Register when the Link Capabilities 2 Register is not available. The Supported Link Speeds Vector in the Link Capabilities Register 2 corresponds to the bus below on Root Ports and Downstream Ports, whereas it corresponds to the bus above on Upstream Ports and Endpoints (PCIe r6.1 sec 7.5.3.18): "Supported Link Speeds Vector - This field indicates the supported Link speed(s) of the associated Port." Add supported_speeds into the struct pci_dev that caches the Supported Link Speeds Vector. supported_speeds contains a set of Link Speeds only in the case where PCIe Link Speed can be determined. The Root Complex Integrated Endpoints do not have a well-defined Link Speed because they do not seem to implement either of the Link Capabilities Registers, which is allowed by PCIe r6.1 sec 7.5.3 (the same limitation applies to determining cur_bus_speed and max_bus_speed that are PCI_SPEED_UNKNOWN in such case). This is of no concern from PCIe bandwidth controller point of view because such devices are not attached into a PCIe Root Port that could be controlled. supported_speeds field keeps the extra reserved zero at the least significant bit to match the Link Capabilities 2 Register layouting. An attempt was made to store supported_speeds field into the struct pci_bus as an intersection of the both ends of the Link, however, the subordinate struct pci_bus is not available early enough. The Target Speed quirk (in pcie_failed_link_retrain()) can run either during initial scan or later requiring it to use the API PCIe bandwidth controller provides to set the Target Link Speed in order to co-exist with the bandwidth controller. When the Target Speed quirk is calling the bandwidth controller during initial scan, the struct pci_bus is not yet initialized. As such, storing supported_speeds into the struct pci_bus is not viable. Suggested-by: Lukas Wunner Signed-off-by: Ilpo Järvinen --- drivers/pci/pci.c | 58 ++++++++++++++++++++++++----------- drivers/pci/probe.c | 3 ++ include/linux/pci.h | 11 ++++++- include/uapi/linux/pci_regs.h | 1 + 4 files changed, 54 insertions(+), 19 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d46652760b11..699531d9d112 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6169,38 +6169,60 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, EXPORT_SYMBOL(pcie_bandwidth_available); /** - * pcie_get_speed_cap - query for the PCI device's link speed capability + * pcie_get_supported_speeds - query Supported Link Speed Vector * @dev: PCI device to query * - * Query the PCI device speed capability. Return the maximum link speed - * supported by the device. + * Query @dev supported link speeds. + * + * Implementation Note in PCIe r6.0.1 sec 7.5.3.18 recommends determining + * supported link speeds using the Supported Link Speeds Vector in the Link + * Capabilities 2 Register (when available). + * + * Link Capabilities 2 was added in PCIe r3.0, sec 7.8.18. + * + * Without Link Capabilities 2, i.e., prior to PCIe r3.0, Supported Link + * Speeds field in Link Capabilities is used and only 2.5 GT/s and 5.0 GT/s + * speeds were defined. + * + * For @dev without Supported Link Speed Vector, the field is synthetized + * from the Max Link Speed field in the Link Capabilities Register. + * + * Return: Supported Link Speeds Vector */ -enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev) +u8 pcie_get_supported_speeds(struct pci_dev *dev) { u32 lnkcap2, lnkcap; + u8 speeds; - /* - * Link Capabilities 2 was added in PCIe r3.0, sec 7.8.18. The - * implementation note there recommends using the Supported Link - * Speeds Vector in Link Capabilities 2 when supported. - * - * Without Link Capabilities 2, i.e., prior to PCIe r3.0, software - * should use the Supported Link Speeds field in Link Capabilities, - * where only 2.5 GT/s and 5.0 GT/s speeds were defined. - */ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP2, &lnkcap2); + speeds = lnkcap2 & PCI_EXP_LNKCAP2_SLS; /* PCIe r3.0-compliant */ - if (lnkcap2) - return PCIE_LNKCAP2_SLS2SPEED(lnkcap2); + if (speeds) + return speeds; pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap); + + /* Synthetize from the Max Link Speed field */ if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_5_0GB) - return PCIE_SPEED_5_0GT; + speeds = PCI_EXP_LNKCAP2_SLS_5_0GB | PCI_EXP_LNKCAP2_SLS_2_5GB; else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_2_5GB) - return PCIE_SPEED_2_5GT; + speeds = PCI_EXP_LNKCAP2_SLS_2_5GB; + + return speeds; +} - return PCI_SPEED_UNKNOWN; +/** + * pcie_get_speed_cap - query for the PCI device's link speed capability + * @dev: PCI device to query + * + * Query the PCI device speed capability. + * + * Return: the maximum link speed supported by the device. + */ +enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev) +{ + return PCIE_LNKCAP2_SLS2SPEED(dev->supported_speeds); } EXPORT_SYMBOL(pcie_get_speed_cap); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b14b9876c030..761b0538afe6 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1945,6 +1945,9 @@ int pci_setup_device(struct pci_dev *dev) set_pcie_untrusted(dev); + if (pci_is_pcie(dev)) + dev->supported_speeds = pcie_get_supported_speeds(dev); + /* "Unknown power state" */ dev->current_state = PCI_UNKNOWN; diff --git a/include/linux/pci.h b/include/linux/pci.h index 25362d577824..56ad75c4c994 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -303,6 +303,7 @@ enum pci_bus_speed { PCI_SPEED_UNKNOWN = 0xff, }; +u8 pcie_get_supported_speeds(struct pci_dev *dev); enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev); enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev); @@ -318,7 +319,14 @@ struct pci_sriov; struct pci_p2pdma; struct rcec_ea; -/* The pci_dev structure describes PCI devices */ +/* struct pci_dev - describes a PCI device + * + * @supported_speeds: PCIe Supported Link Speeds Vector (+ reserved 0 at + * LSB). 0 when the supported speeds cannot be + * determined (e.g., for Root Complex Integrated + * Endpoints without the relevant Capability + * Registers). + */ struct pci_dev { struct list_head bus_list; /* Node in per-bus list */ struct pci_bus *bus; /* Bus this device is on */ @@ -518,6 +526,7 @@ struct pci_dev { struct xarray doe_mbs; /* Data Object Exchange mailboxes */ #endif u16 acs_cap; /* ACS Capability offset */ + u8 supported_speeds; /* Supported Link Speeds Vector */ phys_addr_t rom; /* Physical address if not from BAR */ size_t romlen; /* Length if not from BAR */ /* diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 94c00996e633..b8140fc184cc 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -676,6 +676,7 @@ #define PCI_EXP_DEVSTA2 0x2a /* Device Status 2 */ #define PCI_CAP_EXP_RC_ENDPOINT_SIZEOF_V2 0x2c /* end of v2 EPs w/o link */ #define PCI_EXP_LNKCAP2 0x2c /* Link Capabilities 2 */ +#define PCI_EXP_LNKCAP2_SLS 0x000000fe /* Supported Link Speeds Vector */ #define PCI_EXP_LNKCAP2_SLS_2_5GB 0x00000002 /* Supported Speed 2.5GT/s */ #define PCI_EXP_LNKCAP2_SLS_5_0GB 0x00000004 /* Supported Speed 5GT/s */ #define PCI_EXP_LNKCAP2_SLS_8_0GB 0x00000008 /* Supported Speed 8GT/s */ From patchwork Tue Sep 10 12:27:00 2024 Content-Type: text/plain; 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10 Sep 2024 05:27:53 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , =?utf-8?q?Ilpo_J=C3=A4r?= =?utf-8?q?vinen?= Subject: [PATCH v7 3/8] PCI: Refactor pcie_update_link_speed() Date: Tue, 10 Sep 2024 15:27:00 +0300 Message-Id: <20240910122705.4068-4-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 pcie_update_link_speed() is passed the Link Status register but not all callers have that value at hand nor need the value. Refactor pcie_update_link_speed() to include reading the Link Status register and create __pcie_update_link_speed() which can be used by the hotplug code that has the register value at hand beforehand (and needs the value for other purposes). Signed-off-by: Ilpo Järvinen --- drivers/pci/hotplug/pciehp_hpc.c | 2 +- drivers/pci/pci.h | 7 ++++++- drivers/pci/probe.c | 12 +++++++----- 3 files changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 061f01f60db4..b83ed2727c2f 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -319,7 +319,7 @@ int pciehp_check_link_status(struct controller *ctrl) return -1; } - pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status); + __pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status); if (!found) { ctrl_info(ctrl, "Slot(%s): No device found\n", diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 7c06e55c5072..d723cf48c67a 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -360,7 +360,12 @@ enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev); enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev); void __pcie_print_link_status(struct pci_dev *dev, bool verbose); void pcie_report_downtraining(struct pci_dev *dev); -void pcie_update_link_speed(struct pci_bus *bus, u16 link_status); + +static inline void __pcie_update_link_speed(struct pci_bus *bus, u16 linksta) +{ + bus->cur_bus_speed = pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS]; +} +void pcie_update_link_speed(struct pci_bus *bus); /* Single Root I/O Virtualization */ struct pci_sriov { diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 761b0538afe6..1b3747069464 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -742,9 +742,13 @@ const char *pci_speed_string(enum pci_bus_speed speed) } EXPORT_SYMBOL_GPL(pci_speed_string); -void pcie_update_link_speed(struct pci_bus *bus, u16 linksta) +void pcie_update_link_speed(struct pci_bus *bus) { - bus->cur_bus_speed = pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS]; + struct pci_dev *bridge = bus->self; + u16 linksta; + + pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); + __pcie_update_link_speed(bus, linksta); } EXPORT_SYMBOL_GPL(pcie_update_link_speed); @@ -827,13 +831,11 @@ static void pci_set_bus_speed(struct pci_bus *bus) if (pci_is_pcie(bridge)) { u32 linkcap; - u16 linksta; pcie_capability_read_dword(bridge, PCI_EXP_LNKCAP, &linkcap); bus->max_bus_speed = pcie_link_speed[linkcap & PCI_EXP_LNKCAP_SLS]; - pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); - pcie_update_link_speed(bus, linksta); + pcie_update_link_speed(bus); } } From patchwork Tue Sep 10 12:27:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 13798410 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 C90B818F2D5; Tue, 10 Sep 2024 12:28:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal: i=1; a=rsa-sha256; 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d="scan'208";a="28604252" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:28:15 -0700 X-CSE-ConnectionGUID: wdpanONkT4Gojn87RMerAA== X-CSE-MsgGUID: 0c3XiSqrSE2cihw3XNJqdw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="67543078" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.245.224]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:28:07 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , =?utf-8?q?Ilpo_J=C3=A4r?= =?utf-8?q?vinen?= Subject: [PATCH v7 4/8] PCI/quirks: Abstract LBMS seen check into own function Date: Tue, 10 Sep 2024 15:27:01 +0300 Message-Id: <20240910122705.4068-5-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The Target Speed quirk in pcie_failed_link_retrain() uses the presence of LBMS bit as one of the triggering conditions effectively monopolizing the use of that bit. An upcoming change will introduce a PCIe bandwidth controller which sets up an interrupt to track LBMS. As LBMS will be cleared by the interrupt handler, the Target Speed quirk will no longer be able to observe LBMS directly. As a preparatory step for the change, extract the LBMS seen check into own function out of pcie_failed_link_retrain(). Signed-off-by: Ilpo Järvinen --- drivers/pci/quirks.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 5d57ea27dbc4..6fd9e8401c74 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -33,6 +33,11 @@ #include #include "pci.h" +static bool pcie_lbms_seen(struct pci_dev *dev, u16 lnksta) +{ + return lnksta & PCI_EXP_LNKSTA_LBMS; +} + /* * Retrain the link of a downstream PCIe port by hand if necessary. * @@ -96,8 +101,7 @@ int pcie_failed_link_retrain(struct pci_dev *dev) pcie_capability_read_word(dev, PCI_EXP_LNKCTL2, &lnkctl2); pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); - if ((lnksta & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_DLLLA)) == - PCI_EXP_LNKSTA_LBMS) { + if (!(lnksta & PCI_EXP_LNKSTA_DLLLA) && pcie_lbms_seen(dev, lnksta)) { u16 oldlnkctl2 = lnkctl2; pci_info(dev, "broken device, retraining non-functional downstream link at 2.5GT/s\n"); From patchwork Tue Sep 10 12:27:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 13798411 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 D0E431E493; Tue, 10 Sep 2024 12:28:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725971312; cv=none; b=JB842IWdd758RG94g/6coeBE0c2axHIHwmOZHctyrnAhkgS7EumoXo5yb9kNjN10F3RkH0hx7xH9QX3E+NgEtj7fdeWzCbGTu6nPCLjiKfssiD6AKgykmVy6CSfmZdwVcOchf7DysnUmmAYtOPwGrjqFFpnx+LQ29X6V/ika0Ks= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725971312; c=relaxed/simple; bh=PCCHWdkwm+KEtuH6zXmZMluHB2MloSr8fbNQUH/NKDg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=doMRH2NQ1y/RfeO9pTdx2/xkTbz3H8/LHGzV8IKhPiwjuTolSj0SjSuxHLTiLxJgBe5GoP/c2reZMEAxpqdufGnQ5mg1CXWEYg9kxzlsYxPdL3IL5FmWpdiQCViEx2g7Mb+sYUIvcPb6gLjWXE+qIMwKbZ7KJtonuHh4s4MIn3w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=UC1Y8i4I; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UC1Y8i4I" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1725971311; x=1757507311; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PCCHWdkwm+KEtuH6zXmZMluHB2MloSr8fbNQUH/NKDg=; b=UC1Y8i4I2xO8cTRfRmndGoNKdtGdLCC8WFOOwWKBYJ//xs0rzPIA1ZN9 XwKAPiU2iefa6s10raDDoBdtAvZ6LayvXIY2yPFzZ9ublOpR5Jkb0/yC/ L/27HV4yJ68YxDZjX8e7Ad/rjw2fvgujb4h494aQfc0PqUAwLlpPTqxQz s8AXHJbBRAgTM5l6kZLrhEvJUQ+gIlUQVK0QCW2rQlPlaglGulyKSlWSz EApyipXAtfbgOe7jNDP/+LMAquFZUDHB9e+ZUSicS2fQig0OUOhuHZ7cZ 47DEOmeJAlXccvS3w8xHPNVSIYBC56/K1oocLNB6CeZf8BoexEGAlKv5g g==; X-CSE-ConnectionGUID: BJrPcoSjRCOha5zGoD5uNg== X-CSE-MsgGUID: c84k1wcMTvm+GRVhJAYH3A== X-IronPort-AV: E=McAfee;i="6700,10204,11190"; a="28604311" X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="28604311" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:28:30 -0700 X-CSE-ConnectionGUID: SI7qDs4rR8mqdgmqeBJJaQ== X-CSE-MsgGUID: lQTcgyElTUGaEIPBpkya2g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="67543090" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.245.224]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:28:22 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , =?utf-8?q?Ilpo_?= =?utf-8?q?J=C3=A4rvinen?= , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , Jonathan Cameron Subject: [PATCH v7 5/8] PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller Date: Tue, 10 Sep 2024 15:27:02 +0300 Message-Id: <20240910122705.4068-6-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This mostly reverts the commit b4c7d2076b4e ("PCI/LINK: Remove bandwidth notification"). An upcoming commit extends this driver building PCIe bandwidth controller on top of it. The PCIe bandwidth notification were first added in the commit e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification") but later had to be removed. The significant changes compared with the old bandwidth notification driver include: 1) Don't print the notifications into kernel log, just keep the Link Speed cached into the struct pci_bus updated. While somewhat unfortunate, the log spam was the source of complaints that eventually lead to the removal of the bandwidth notifications driver (see the links below for further information). 2) Besides the Link Bandwidth Management Interrupt, enable also Link Autonomous Bandwidth Interrupt to cover the other source of bandwidth changes. 3) Use threaded IRQ with IRQF_ONESHOT to handle Bandwidth Notification Interrupts to address the problem fixed in the commit 3e82a7f9031f ("PCI/LINK: Supply IRQ handler so level-triggered IRQs are acked")). 4) Handle Link Speed updates robustly. Refresh the cached Link Speed when enabling Bandwidth Notification Interrupts, and solve the race between Link Speed read and LBMS/LABS update in pcie_bwnotif_irq_thread(). 5) Use concurrency safe LNKCTL RMW operations. 6) The driver is now called PCIe bwctrl (bandwidth controller) instead of just bandwidth notifications because of increased scope and functionality within the driver. 7) Coexist with the Target Link Speed quirk in pcie_failed_link_retrain(). Provide LBMS counting API for it. 8) Tweaks to variable/functions names for consistency and length reasons. Bandwidth Notifications enable the cur_bus_speed in the struct pci_bus to keep track PCIe Link Speed changes. Link: https://lore.kernel.org/all/20190429185611.121751-1-helgaas@kernel.org/ Link: https://lore.kernel.org/linux-pci/20190501142942.26972-1-keith.busch@intel.com/ Link: https://lore.kernel.org/linux-pci/20200115221008.GA191037@google.com/ Suggested-by: Lukas Wunner # Building bwctrl on top of bwnotif Signed-off-by: Ilpo Järvinen Reviewed-by: Jonathan Cameron --- MAINTAINERS | 6 + drivers/pci/hotplug/pciehp_ctrl.c | 5 + drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 15 +++ drivers/pci/pcie/Kconfig | 12 ++ drivers/pci/pcie/Makefile | 1 + drivers/pci/pcie/bwctrl.c | 190 ++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv.c | 9 +- drivers/pci/pcie/portdrv.h | 10 +- drivers/pci/quirks.c | 9 +- include/linux/pci.h | 4 + 11 files changed, 255 insertions(+), 8 deletions(-) create mode 100644 drivers/pci/pcie/bwctrl.c diff --git a/MAINTAINERS b/MAINTAINERS index 42decde38320..d2e418350883 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17669,6 +17669,12 @@ F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* +PCIE BANDWIDTH CONTROLLER +M: Ilpo Järvinen +L: linux-pci@vger.kernel.org +S: Supported +F: drivers/pci/pcie/bwctrl.c + PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron L: linux-pci@vger.kernel.org diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index dcdbfcf404dd..d603a7aa7483 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -19,6 +19,8 @@ #include #include #include + +#include "../pci.h" #include "pciehp.h" /* The following routines constitute the bulk of the @@ -127,6 +129,9 @@ static void remove_board(struct controller *ctrl, bool safe_removal) pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF, INDICATOR_NOOP); + + /* Don't carry LBMS indications across */ + pcie_reset_lbms_count(ctrl->pcie->port); } static int pciehp_enable_slot(struct controller *ctrl); diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 699531d9d112..a10ca0e80ce9 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4724,7 +4724,7 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt) * to track link speed or width changes made by hardware itself * in attempt to correct unreliable link operation. */ - pcie_capability_write_word(pdev, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS); + pcie_reset_lbms_count(pdev); return rc; } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index d723cf48c67a..869677ff752f 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -671,6 +671,21 @@ static inline void pcie_set_ecrc_checking(struct pci_dev *dev) { } static inline void pcie_ecrc_get_policy(char *str) { } #endif +#ifdef CONFIG_PCIE_BWCTRL +void pcie_reset_lbms_count(struct pci_dev *port); +int pcie_lbms_count(struct pci_dev *port, unsigned long *val); +#elif defined(CONFIG_PCI) +static inline void pcie_reset_lbms_count(struct pci_dev *port) +{ + pcie_capability_write_word(port, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS); +} + +static inline int pcie_lbms_count(struct pci_dev *port, unsigned long *val) +{ + return -EOPNOTSUPP; +} +#endif + struct pci_dev_reset_methods { u16 vendor; u16 device; diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 17919b99fa66..a8c27e37b3c7 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -146,6 +146,18 @@ config PCIE_PTM This is only useful if you have devices that support PTM, but it is safe to enable even if you don't. +config PCIE_BWCTRL + bool "PCI Express Bandwidth Controller" + depends on PCIEPORTBUS + help + This enables PCI Express Bandwidth Controller. The Bandwidth + Controller allows controlling PCIe Link Speed and listens for Link + Bandwidth Change Notifications. The current Link Speed is available + through /sys/bus/pci/devices/.../current_link_speed. + + If you know Link Width or Speed changes occur (e.g., to correct + unreliable links), you may answer Y. + config PCIE_EDR bool "PCI Express Error Disconnect Recover support" depends on PCIE_DPC && ACPI diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index 6461aa93fe76..6357bc219632 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -12,4 +12,5 @@ obj-$(CONFIG_PCIEAER_INJECT) += aer_inject.o obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_DPC) += dpc.o obj-$(CONFIG_PCIE_PTM) += ptm.o +obj-$(CONFIG_PCIE_BWCTRL) += bwctrl.o obj-$(CONFIG_PCIE_EDR) += edr.o diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c new file mode 100644 index 000000000000..1b11b5da79d4 --- /dev/null +++ b/drivers/pci/pcie/bwctrl.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * PCIe bandwidth controller + * + * Author: Alexandru Gagniuc + * + * Copyright (C) 2019 Dell Inc + * Copyright (C) 2023-2024 Intel Corporation + * + * This service port driver hooks into the Bandwidth Notification interrupt + * watching for changes or links becoming degraded in operation. It updates + * the cached Current Link Speed that is exposed to user space through sysfs. + */ + +#define dev_fmt(fmt) "bwctrl: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../pci.h" +#include "portdrv.h" + +/** + * struct pcie_bwctrl_data - PCIe bandwidth controller + * @lbms_count: Count for LBMS (since last reset) + */ +struct pcie_bwctrl_data { + atomic_t lbms_count; +}; + +/* Prevents port removal during link speed changes and LBMS count accessors */ +static DECLARE_RWSEM(pcie_bwctrl_remove_rwsem); + +static void pcie_bwnotif_enable(struct pcie_device *srv) +{ + struct pcie_bwctrl_data *data = get_service_data(srv); + struct pci_dev *port = srv->port; + u16 link_status; + int ret; + + /* Count LBMS seen so far as one */ + ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status); + if (ret == PCIBIOS_SUCCESSFUL && link_status & PCI_EXP_LNKSTA_LBMS) + atomic_inc(&data->lbms_count); + + pcie_capability_set_word(port, PCI_EXP_LNKCTL, + PCI_EXP_LNKCTL_LBMIE | PCI_EXP_LNKCTL_LABIE); + pcie_capability_write_word(port, PCI_EXP_LNKSTA, + PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_LABS); + + /* + * Update after enabling notifications & clearing status bits ensures + * link speed is up to date. + */ + pcie_update_link_speed(port->subordinate); +} + +static void pcie_bwnotif_disable(struct pci_dev *port) +{ + pcie_capability_clear_word(port, PCI_EXP_LNKCTL, + PCI_EXP_LNKCTL_LBMIE | PCI_EXP_LNKCTL_LABIE); +} + +static irqreturn_t pcie_bwnotif_irq_thread(int irq, void *context) +{ + struct pcie_device *srv = context; + struct pcie_bwctrl_data *data = get_service_data(srv); + struct pci_dev *port = srv->port; + u16 link_status, events; + int ret; + + ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status); + if (ret != PCIBIOS_SUCCESSFUL) + return IRQ_NONE; + + events = link_status & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_LABS); + if (!events) + return IRQ_NONE; + + if (events & PCI_EXP_LNKSTA_LBMS) + atomic_inc(&data->lbms_count); + + pcie_capability_write_word(port, PCI_EXP_LNKSTA, events); + + /* + * Interrupts will not be triggered from any further Link Speed + * change until LBMS is cleared by the write. Therefore, re-read the + * speed (inside pcie_update_link_speed()) after LBMS has been + * cleared to avoid missing link speed changes. + */ + pcie_update_link_speed(port->subordinate); + + return IRQ_HANDLED; +} + +void pcie_reset_lbms_count(struct pci_dev *port) +{ + struct pcie_bwctrl_data *data; + + guard(rwsem_read)(&pcie_bwctrl_remove_rwsem); + data = port->link_bwctrl; + if (data) + atomic_set(&data->lbms_count, 0); + else + pcie_capability_write_word(port, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS); +} + +int pcie_lbms_count(struct pci_dev *port, unsigned long *val) +{ + struct pcie_bwctrl_data *data; + + guard(rwsem_read)(&pcie_bwctrl_remove_rwsem); + data = port->link_bwctrl; + if (!data) + return -ENOTTY; + + *val = atomic_read(&data->lbms_count); + + return 0; +} + +static int pcie_bwnotif_probe(struct pcie_device *srv) +{ + struct pci_dev *port = srv->port; + int ret; + + struct pcie_bwctrl_data *data __free(kfree) = + kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + set_service_data(srv, data); + + ret = request_threaded_irq(srv->irq, NULL, pcie_bwnotif_irq_thread, + IRQF_SHARED | IRQF_ONESHOT, "PCIe bwctrl", srv); + if (ret) + return ret; + + port->link_bwctrl = no_free_ptr(data); + pcie_bwnotif_enable(srv); + + pci_dbg(port, "enabled with IRQ %d\n", srv->irq); + + return 0; +} + +static void pcie_bwnotif_remove(struct pcie_device *srv) +{ + struct pcie_bwctrl_data *data = get_service_data(srv); + + pcie_bwnotif_disable(srv->port); + scoped_guard(rwsem_write, &pcie_bwctrl_remove_rwsem) + srv->port->link_bwctrl = NULL; + + free_irq(srv->irq, srv); + kfree(data); +} + +static int pcie_bwnotif_suspend(struct pcie_device *srv) +{ + pcie_bwnotif_disable(srv->port); + return 0; +} + +static int pcie_bwnotif_resume(struct pcie_device *srv) +{ + pcie_bwnotif_enable(srv); + return 0; +} + +static struct pcie_port_service_driver pcie_bwctrl_driver = { + .name = "pcie_bwctrl", + .port_type = PCIE_ANY_PORT, + .service = PCIE_PORT_SERVICE_BWCTRL, + .probe = pcie_bwnotif_probe, + .suspend = pcie_bwnotif_suspend, + .resume = pcie_bwnotif_resume, + .remove = pcie_bwnotif_remove, +}; + +int __init pcie_bwctrl_init(void) +{ + return pcie_port_service_register(&pcie_bwctrl_driver); +} diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index 6af5e0425872..5e10306b6308 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -68,7 +68,7 @@ static int pcie_message_numbers(struct pci_dev *dev, int mask, */ if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP | - PCIE_PORT_SERVICE_BWNOTIF)) { + PCIE_PORT_SERVICE_BWCTRL)) { pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16); *pme = FIELD_GET(PCI_EXP_FLAGS_IRQ, reg16); nvec = *pme + 1; @@ -150,11 +150,11 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask) /* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */ if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP | - PCIE_PORT_SERVICE_BWNOTIF)) { + PCIE_PORT_SERVICE_BWCTRL)) { pcie_irq = pci_irq_vector(dev, pme); irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq; irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq; - irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq; + irqs[PCIE_PORT_SERVICE_BWCTRL_SHIFT] = pcie_irq; } if (mask & PCIE_PORT_SERVICE_AER) @@ -271,7 +271,7 @@ static int get_port_device_capability(struct pci_dev *dev) pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap); if (linkcap & PCI_EXP_LNKCAP_LBNC) - services |= PCIE_PORT_SERVICE_BWNOTIF; + services |= PCIE_PORT_SERVICE_BWCTRL; } return services; @@ -828,6 +828,7 @@ static void __init pcie_init_services(void) pcie_aer_init(); pcie_pme_init(); pcie_dpc_init(); + pcie_bwctrl_init(); pcie_hp_init(); } diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 12c89ea0313b..13366175da22 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -20,8 +20,8 @@ #define PCIE_PORT_SERVICE_HP (1 << PCIE_PORT_SERVICE_HP_SHIFT) #define PCIE_PORT_SERVICE_DPC_SHIFT 3 /* Downstream Port Containment */ #define PCIE_PORT_SERVICE_DPC (1 << PCIE_PORT_SERVICE_DPC_SHIFT) -#define PCIE_PORT_SERVICE_BWNOTIF_SHIFT 4 /* Bandwidth notification */ -#define PCIE_PORT_SERVICE_BWNOTIF (1 << PCIE_PORT_SERVICE_BWNOTIF_SHIFT) +#define PCIE_PORT_SERVICE_BWCTRL_SHIFT 4 /* Bandwidth Controller (notifications) */ +#define PCIE_PORT_SERVICE_BWCTRL (1 << PCIE_PORT_SERVICE_BWCTRL_SHIFT) #define PCIE_PORT_DEVICE_MAXSERVICES 5 @@ -51,6 +51,12 @@ int pcie_dpc_init(void); static inline int pcie_dpc_init(void) { return 0; } #endif +#ifdef CONFIG_PCIE_BWCTRL +int pcie_bwctrl_init(void); +#else +static inline int pcie_bwctrl_init(void) { return 0; } +#endif + /* Port Type */ #define PCIE_ANY_PORT (~0) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 6fd9e8401c74..64d9f8559f65 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -35,7 +35,14 @@ static bool pcie_lbms_seen(struct pci_dev *dev, u16 lnksta) { - return lnksta & PCI_EXP_LNKSTA_LBMS; + unsigned long count; + int ret; + + ret = pcie_lbms_count(dev, &count); + if (ret < 0) + return lnksta & PCI_EXP_LNKSTA_LBMS; + + return count > 0; } /* diff --git a/include/linux/pci.h b/include/linux/pci.h index 56ad75c4c994..d77816f0193f 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -314,6 +314,7 @@ struct pci_vpd { }; struct irq_affinity; +struct pcie_bwctrl_data; struct pcie_link_state; struct pci_sriov; struct pci_p2pdma; @@ -502,6 +503,9 @@ struct pci_dev { unsigned int dpc_rp_extensions:1; u8 dpc_rp_log_size; #endif +#ifdef CONFIG_PCIE_BWCTRL + struct pcie_bwctrl_data *link_bwctrl; +#endif #ifdef CONFIG_PCI_ATS union { struct pci_sriov *sriov; /* PF: SR-IOV info */ From patchwork Tue Sep 10 12:27:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Ilpo_J=C3=A4rvinen?= X-Patchwork-Id: 13798412 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (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 CE20F1E493; Tue, 10 Sep 2024 12:28:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725971329; cv=none; b=Smc3/B2+L6JCTlmM5/skf6h54pSBsJrMTdMu7zofj+0jFsiK+wIH5HTB7TsqG0wQRgZRaoCJ3WdfT8TrNjW/8QRq21pwOBktxEC7zXmJ3h5H74bU7jgoQW4knPJK75ckGPjSMmWxqrmIcx4zbEbHlZRaj9fB59Sqe+zf3hPnzW0= ARC-Message-Signature: i=1; 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d="scan'208";a="71787584" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.245.224]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:28:38 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , =?utf-8?q?Ilpo_?= =?utf-8?q?J=C3=A4rvinen?= , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET Subject: [PATCH v7 6/8] PCI/bwctrl: Add API to set PCIe Link Speed Date: Tue, 10 Sep 2024 15:27:03 +0300 Message-Id: <20240910122705.4068-7-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Currently, PCIe Link Speeds are adjusted by custom code rather than in a common function provided in PCI core. PCIe bandwidth controller (bwctrl) introduces an in-kernel API to set PCIe Link Speed. Convert Target Speed quirk to use the new API. The Target Speed quirk runs very early when bwctrl is not yet probed for a Port and can also run later when bwctrl is already setup for the Port. Also, the new API has to be available for the Target Speed quirk when bwctrl is not enabled by the config. The cases when bwctrl is not setup for the port use less locking which is handled by a few locking wrappers. The new API is also intended to be used in an upcoming commit that adds a thermal cooling device to throttle PCIe bandwidth when thermal thresholds are reached. The PCIe bandwidth control procedure is as follows. The highest speed supported by the Port and the PCIe device which is not higher than the requested speed is selected and written into the Target Link Speed in the Link Control 2 Register. Then bandwidth controller retrains the PCIe Link. Bandwidth Notifications enable the cur_bus_speed in the struct pci_bus to keep track PCIe Link Speed changes. While Bandwidth Notifications should also be generated when bandwidth controller alters the PCIe Link Speed, a few platforms do not deliver LMBS interrupt after Link Training as expected. Thus, after changing the Link Speed, bandwidth controller makes additional read for the Link Status Register to ensure cur_bus_speed is consistent with the new PCIe Link Speed. Signed-off-by: Ilpo Järvinen --- drivers/pci/pci.h | 20 ++++ drivers/pci/pcie/Makefile | 2 +- drivers/pci/pcie/bwctrl.c | 200 +++++++++++++++++++++++++++++++++++++- drivers/pci/quirks.c | 17 +--- include/linux/pci.h | 3 + 5 files changed, 226 insertions(+), 16 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 869677ff752f..7f0e71f3ce67 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -313,6 +313,17 @@ void pci_disable_bridge_window(struct pci_dev *dev); struct pci_bus *pci_bus_get(struct pci_bus *bus); void pci_bus_put(struct pci_bus *bus); +#define PCIE_LNKCAP_SLS2SPEED(lnkcap) \ +({ \ + (lnkcap == PCI_EXP_LNKCAP_SLS_64_0GB ? PCIE_SPEED_64_0GT : \ + lnkcap == PCI_EXP_LNKCAP_SLS_32_0GB ? PCIE_SPEED_32_0GT : \ + lnkcap == PCI_EXP_LNKCAP_SLS_16_0GB ? PCIE_SPEED_16_0GT : \ + lnkcap == PCI_EXP_LNKCAP_SLS_8_0GB ? PCIE_SPEED_8_0GT : \ + lnkcap == PCI_EXP_LNKCAP_SLS_5_0GB ? PCIE_SPEED_5_0GT : \ + lnkcap == PCI_EXP_LNKCAP_SLS_2_5GB ? PCIE_SPEED_2_5GT : \ + PCI_SPEED_UNKNOWN); \ +}) + /* PCIe link information from Link Capabilities 2 */ #define PCIE_LNKCAP2_SLS2SPEED(lnkcap2) \ ((lnkcap2) & PCI_EXP_LNKCAP2_SLS_64_0GB ? PCIE_SPEED_64_0GT : \ @@ -323,6 +334,15 @@ void pci_bus_put(struct pci_bus *bus); (lnkcap2) & PCI_EXP_LNKCAP2_SLS_2_5GB ? PCIE_SPEED_2_5GT : \ PCI_SPEED_UNKNOWN) +#define PCIE_LNKCTL2_TLS2SPEED(lnkctl2) \ + ((lnkctl2) == PCI_EXP_LNKCTL2_TLS_64_0GT ? PCIE_SPEED_64_0GT : \ + (lnkctl2) == PCI_EXP_LNKCTL2_TLS_32_0GT ? PCIE_SPEED_32_0GT : \ + (lnkctl2) == PCI_EXP_LNKCTL2_TLS_16_0GT ? PCIE_SPEED_16_0GT : \ + (lnkctl2) == PCI_EXP_LNKCTL2_TLS_8_0GT ? PCIE_SPEED_8_0GT : \ + (lnkctl2) == PCI_EXP_LNKCTL2_TLS_5_0GT ? PCIE_SPEED_5_0GT : \ + (lnkctl2) == PCI_EXP_LNKCTL2_TLS_2_5GT ? PCIE_SPEED_2_5GT : \ + PCI_SPEED_UNKNOWN) + /* PCIe speed to Mb/s reduced by encoding overhead */ #define PCIE_SPEED2MBS_ENC(speed) \ ((speed) == PCIE_SPEED_64_0GT ? 64000*1/1 : \ diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index 6357bc219632..e8cf58a0fa3f 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -12,5 +12,5 @@ obj-$(CONFIG_PCIEAER_INJECT) += aer_inject.o obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_DPC) += dpc.o obj-$(CONFIG_PCIE_PTM) += ptm.o -obj-$(CONFIG_PCIE_BWCTRL) += bwctrl.o +obj-y += bwctrl.o obj-$(CONFIG_PCIE_EDR) += edr.o diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 1b11b5da79d4..cc245aaf8d5e 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -7,6 +7,11 @@ * Copyright (C) 2019 Dell Inc * Copyright (C) 2023-2024 Intel Corporation * + * The PCIe bandwidth controller provides a way to alter PCIe Link Speeds + * and notify the operating system when the Link Width or Speed changes. The + * notification capability is required for all Root Ports and Downstream + * Ports supporting Link Width wider than x1 and/or multiple Link Speeds. + * * This service port driver hooks into the Bandwidth Notification interrupt * watching for changes or links becoming degraded in operation. It updates * the cached Current Link Speed that is exposed to user space through sysfs. @@ -15,9 +20,12 @@ #define dev_fmt(fmt) "bwctrl: " fmt #include +#include +#include #include #include #include +#include #include #include #include @@ -28,15 +36,198 @@ /** * struct pcie_bwctrl_data - PCIe bandwidth controller + * @set_speed_mutex: Serializes link speed changes * @lbms_count: Count for LBMS (since last reset) */ struct pcie_bwctrl_data { + struct mutex set_speed_mutex; atomic_t lbms_count; }; +#ifdef CONFIG_PCIE_BWCTRL /* Prevents port removal during link speed changes and LBMS count accessors */ static DECLARE_RWSEM(pcie_bwctrl_remove_rwsem); +static inline void pcie_bwctrl_remove_rwsem_down_read(void) +{ + down_read(&pcie_bwctrl_remove_rwsem); +} + +static inline void pcie_bwctrl_remove_rwsem_up_read(void) +{ + up_read(&pcie_bwctrl_remove_rwsem); +} + +static inline void pcie_bwctrl_port_mutex_lock(struct pci_dev *port) +{ + struct pcie_bwctrl_data *data; + + /* + * port->link_bwctrl is NULL when Target Speed quirk runs during + * boot and when bwctrl is not enabled by the config. + */ + data = port->link_bwctrl; + if (!data) + return; + + mutex_lock(&data->set_speed_mutex); +} + +static inline void pcie_bwctrl_port_mutex_unlock(struct pci_dev *port) +{ + struct pcie_bwctrl_data *data; + + /* + * port->link_bwctrl is NULL when Target Speed quirk runs during + * boot and when bwctrl is not enabled by the config. + */ + data = port->link_bwctrl; + if (!data) + return; + + mutex_unlock(&data->set_speed_mutex); +} +#else +static inline void pcie_bwctrl_remove_rwsem_down_read(void) {} +static inline void pcie_bwctrl_remove_rwsem_up_read(void) {} +static inline void pcie_bwctrl_port_mutex_lock(struct pci_dev *port) {} +static inline void pcie_bwctrl_port_mutex_unlock(struct pci_dev *port) {} +#endif /* CONFIG_PCIE_BWCTRL */ + +static bool pcie_valid_speed(enum pci_bus_speed speed) +{ + return (speed >= PCIE_SPEED_2_5GT) && (speed <= PCIE_SPEED_64_0GT); +} + +static u16 pci_bus_speed2lnkctl2(enum pci_bus_speed speed) +{ + static const u8 speed_conv[] = { + [PCIE_SPEED_2_5GT] = PCI_EXP_LNKCTL2_TLS_2_5GT, + [PCIE_SPEED_5_0GT] = PCI_EXP_LNKCTL2_TLS_5_0GT, + [PCIE_SPEED_8_0GT] = PCI_EXP_LNKCTL2_TLS_8_0GT, + [PCIE_SPEED_16_0GT] = PCI_EXP_LNKCTL2_TLS_16_0GT, + [PCIE_SPEED_32_0GT] = PCI_EXP_LNKCTL2_TLS_32_0GT, + [PCIE_SPEED_64_0GT] = PCI_EXP_LNKCTL2_TLS_64_0GT, + }; + + if (WARN_ON_ONCE(!pcie_valid_speed(speed))) + return 0; + + return speed_conv[speed]; +} + +static inline u16 pcie_supported_speeds2target_speed(u8 supported_speeds) +{ + return __fls(supported_speeds); +} + +/** + * pcie_bwctrl_select_speed - Select Target Link Speed + * @port: PCIe Port + * @speed_req: requested PCIe Link Speed + * + * Select Target Link Speed by take into account Supported Link Speeds of + * both the Root Port and the Endpoint. + * + * Return: Target Link Speed (1=2.5GT/s, 2=5GT/s, 3=8GT/s, etc.) + */ +static u16 pcie_bwctrl_select_speed(struct pci_dev *port, enum pci_bus_speed speed_req) +{ + struct pci_bus *bus = port->subordinate; + u8 desired_speeds, supported_speeds; + struct pci_dev *dev; + + desired_speeds = GENMASK(pci_bus_speed2lnkctl2(speed_req), + __fls(PCI_EXP_LNKCAP2_SLS_2_5GB)); + + supported_speeds = port->supported_speeds; + if (bus) { + down_read(&pci_bus_sem); + dev = list_first_entry_or_null(&bus->devices, struct pci_dev, bus_list); + if (dev) + supported_speeds &= dev->supported_speeds; + up_read(&pci_bus_sem); + } + if (!supported_speeds) + return PCI_EXP_LNKCAP2_SLS_2_5GB; + + return pcie_supported_speeds2target_speed(supported_speeds & desired_speeds); +} + +static int pcie_bwctrl_change_speed(struct pci_dev *port, u16 target_speed, bool use_lt) +{ + int ret; + + ret = pcie_capability_clear_and_set_word(port, PCI_EXP_LNKCTL2, + PCI_EXP_LNKCTL2_TLS, target_speed); + if (ret != PCIBIOS_SUCCESSFUL) + return pcibios_err_to_errno(ret); + + ret = pcie_retrain_link(port, use_lt); + if (ret < 0) + return ret; + + /* + * Ensure link speed updates also with platforms that have problems + * with notifications. + */ + if (port->subordinate) + pcie_update_link_speed(port->subordinate); + + return 0; +} + +/** + * pcie_set_target_speed - Set downstream Link Speed for PCIe Port + * @port: PCIe Port + * @speed_req: requested PCIe Link Speed + * @use_lt: Wait for the LT or DLLLA bit to detect the end of link training + * + * Attempts to set PCIe Port Link Speed to @speed_req. @speed_req may be + * adjusted downwards to the best speed supported by both the Port and PCIe + * Device underneath it. + * + * Return: + * * 0 - on success + * * -EINVAL - @speed_req is not a PCIe Link Speed + * * -ENODEV - @port is not controllable + * * -ETIMEDOUT - changing Link Speed took too long + * * -EAGAIN - Link Speed was changed but @speed_req was not achieved + */ +int pcie_set_target_speed(struct pci_dev *port, enum pci_bus_speed speed_req, + bool use_lt) +{ + struct pci_bus *bus = port->subordinate; + u16 target_speed; + int ret; + + if (WARN_ON_ONCE(!pcie_valid_speed(speed_req))) + return -EINVAL; + + if (bus && bus->cur_bus_speed == speed_req) + return 0; + + target_speed = pcie_bwctrl_select_speed(port, speed_req); + + pcie_bwctrl_remove_rwsem_down_read(); + pcie_bwctrl_port_mutex_lock(port); + ret = pcie_bwctrl_change_speed(port, target_speed, use_lt); + pcie_bwctrl_port_mutex_unlock(port); + pcie_bwctrl_remove_rwsem_up_read(); + + /* + * Despite setting higher speed into the Target Link Speed, empty + * bus won't train to 5GT+ speeds. + */ + if (!ret && bus && bus->cur_bus_speed != speed_req && + !list_empty(&bus->devices)) + ret = -EAGAIN; + + return ret; +} +EXPORT_SYMBOL_GPL(pcie_set_target_speed); + +#ifdef CONFIG_PCIE_BWCTRL static void pcie_bwnotif_enable(struct pcie_device *srv) { struct pcie_bwctrl_data *data = get_service_data(srv); @@ -135,6 +326,7 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) if (!data) return -ENOMEM; + mutex_init(&data->set_speed_mutex); set_service_data(srv, data); ret = request_threaded_irq(srv->irq, NULL, pcie_bwnotif_irq_thread, @@ -142,8 +334,10 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) if (ret) return ret; - port->link_bwctrl = no_free_ptr(data); - pcie_bwnotif_enable(srv); + scoped_guard(rwsem_write, &pcie_bwctrl_remove_rwsem) { + port->link_bwctrl = no_free_ptr(data); + pcie_bwnotif_enable(srv); + } pci_dbg(port, "enabled with IRQ %d\n", srv->irq); @@ -159,6 +353,7 @@ static void pcie_bwnotif_remove(struct pcie_device *srv) srv->port->link_bwctrl = NULL; free_irq(srv->irq, srv); + mutex_destroy(&data->set_speed_mutex); kfree(data); } @@ -188,3 +383,4 @@ int __init pcie_bwctrl_init(void) { return pcie_port_service_register(&pcie_bwctrl_driver); } +#endif /* CONFIG_PCIE_BWCTRL */ diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 64d9f8559f65..3bca70da1d45 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -113,16 +113,11 @@ int pcie_failed_link_retrain(struct pci_dev *dev) pci_info(dev, "broken device, retraining non-functional downstream link at 2.5GT/s\n"); - lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; - lnkctl2 |= PCI_EXP_LNKCTL2_TLS_2_5GT; - pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - - ret = pcie_retrain_link(dev, false); + ret = pcie_set_target_speed(dev, PCIE_SPEED_2_5GT, false); if (ret) { pci_info(dev, "retraining failed\n"); - pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, - oldlnkctl2); - pcie_retrain_link(dev, true); + pcie_set_target_speed(dev, PCIE_LNKCTL2_TLS2SPEED(oldlnkctl2), + true); return ret; } @@ -136,11 +131,7 @@ int pcie_failed_link_retrain(struct pci_dev *dev) pci_info(dev, "removing 2.5GT/s downstream link speed restriction\n"); pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap); - lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; - lnkctl2 |= lnkcap & PCI_EXP_LNKCAP_SLS; - pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - - ret = pcie_retrain_link(dev, false); + ret = pcie_set_target_speed(dev, PCIE_LNKCAP_SLS2SPEED(lnkcap), false); if (ret) { pci_info(dev, "retraining failed\n"); return ret; diff --git a/include/linux/pci.h b/include/linux/pci.h index d77816f0193f..3af842e6346d 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1845,6 +1845,9 @@ bool pci_aer_available(void); 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Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , =?utf-8?q?Ilpo_?= =?utf-8?q?J=C3=A4rvinen?= , Daniel Lezcano , Zhang Rui , Lukasz Luba , linux-kernel@vger.kernel.org Cc: Amit Kucheria , Christophe JAILLET , Jonathan Cameron Subject: [PATCH v7 7/8] thermal: Add PCIe cooling driver Date: Tue, 10 Sep 2024 15:27:04 +0300 Message-Id: <20240910122705.4068-8-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add a thermal cooling driver to provide path to access PCIe bandwidth controller using the usual thermal interfaces. A cooling device is instantiated for controllable PCIe Ports from the bwctrl service driver. If registering the cooling device fails, allow bwctrl's probe to succeed regardless. As cdev in that case contains IS_ERR() pseudo "pointer", clean that up inside the probe function so the remove side doesn't need to suddenly make an odd looking IS_ERR() check. The thermal side state 0 means no throttling, i.e., maximum supported PCIe Link Speed. Signed-off-by: Ilpo Järvinen Reviewed-by: Jonathan Cameron Acked-by: Rafael J. Wysocki # From the cooling device interface perspective --- MAINTAINERS | 2 + drivers/pci/pcie/bwctrl.c | 11 +++++ drivers/thermal/Kconfig | 10 +++++ drivers/thermal/Makefile | 2 + drivers/thermal/pcie_cooling.c | 80 ++++++++++++++++++++++++++++++++++ include/linux/pci-bwctrl.h | 28 ++++++++++++ 6 files changed, 133 insertions(+) create mode 100644 drivers/thermal/pcie_cooling.c create mode 100644 include/linux/pci-bwctrl.h diff --git a/MAINTAINERS b/MAINTAINERS index d2e418350883..47542dcb9259 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17674,6 +17674,8 @@ M: Ilpo Järvinen L: linux-pci@vger.kernel.org S: Supported F: drivers/pci/pcie/bwctrl.c +F: drivers/thermal/pcie_cooling.c +F: include/linux/pci-bwctrl.h PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index cc245aaf8d5e..592a14183df8 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -38,10 +39,12 @@ * struct pcie_bwctrl_data - PCIe bandwidth controller * @set_speed_mutex: Serializes link speed changes * @lbms_count: Count for LBMS (since last reset) + * @cdev: thermal cooling device associated with the port */ struct pcie_bwctrl_data { struct mutex set_speed_mutex; atomic_t lbms_count; + struct thermal_cooling_device *cdev; }; #ifdef CONFIG_PCIE_BWCTRL @@ -341,6 +344,11 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) pci_dbg(port, "enabled with IRQ %d\n", srv->irq); + /* Don't fail on errors. Don't leave IS_ERR() "pointer" into ->cdev */ + port->link_bwctrl->cdev = pcie_cooling_device_register(port); + if (IS_ERR(port->link_bwctrl->cdev)) + port->link_bwctrl->cdev = NULL; + return 0; } @@ -348,6 +356,9 @@ static void pcie_bwnotif_remove(struct pcie_device *srv) { struct pcie_bwctrl_data *data = get_service_data(srv); + if (data->cdev) + pcie_cooling_device_unregister(data->cdev); + pcie_bwnotif_disable(srv->port); scoped_guard(rwsem_write, &pcie_bwctrl_remove_rwsem) srv->port->link_bwctrl = NULL; diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index ed16897584b4..648e0478d9d6 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -211,6 +211,16 @@ config DEVFREQ_THERMAL If you want this support, you should say Y here. +config PCIE_THERMAL + bool "PCIe cooling support" + depends on PCIEPORTBUS + select PCIE_BWCTRL + help + This implements PCIe cooling mechanism through bandwidth reduction + for PCIe devices. + + If you want this support, you should say Y here. + config THERMAL_EMULATION bool "Thermal emulation mode support" help diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index ce7a4752ef52..33cb16b06ba5 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -31,6 +31,8 @@ thermal_sys-$(CONFIG_CPU_IDLE_THERMAL) += cpuidle_cooling.o # devfreq cooling thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o +thermal_sys-$(CONFIG_PCIE_THERMAL) += pcie_cooling.o + obj-$(CONFIG_K3_THERMAL) += k3_bandgap.o k3_j72xx_bandgap.o # platform thermal drivers obj-y += broadcom/ diff --git a/drivers/thermal/pcie_cooling.c b/drivers/thermal/pcie_cooling.c new file mode 100644 index 000000000000..a876d64f1582 --- /dev/null +++ b/drivers/thermal/pcie_cooling.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PCIe cooling device + * + * Copyright (C) 2023-2024 Intel Corporation + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define COOLING_DEV_TYPE_PREFIX "PCIe_Port_Link_Speed_" + +static int pcie_cooling_get_max_level(struct thermal_cooling_device *cdev, unsigned long *state) +{ + struct pci_dev *port = cdev->devdata; + + /* cooling state 0 is same as the maximum PCIe speed */ + *state = port->subordinate->max_bus_speed - PCIE_SPEED_2_5GT; + + return 0; +} + +static int pcie_cooling_get_cur_level(struct thermal_cooling_device *cdev, unsigned long *state) +{ + struct pci_dev *port = cdev->devdata; + + /* cooling state 0 is same as the maximum PCIe speed */ + *state = cdev->max_state - (port->subordinate->cur_bus_speed - PCIE_SPEED_2_5GT); + + return 0; +} + +static int pcie_cooling_set_cur_level(struct thermal_cooling_device *cdev, unsigned long state) +{ + struct pci_dev *port = cdev->devdata; + enum pci_bus_speed speed; + + /* cooling state 0 is same as the maximum PCIe speed */ + speed = (cdev->max_state - state) + PCIE_SPEED_2_5GT; + + return pcie_set_target_speed(port, speed, true); +} + +static struct thermal_cooling_device_ops pcie_cooling_ops = { + .get_max_state = pcie_cooling_get_max_level, + .get_cur_state = pcie_cooling_get_cur_level, + .set_cur_state = pcie_cooling_set_cur_level, +}; + +struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port) +{ + char *name __free(kfree) = + kasprintf(GFP_KERNEL, COOLING_DEV_TYPE_PREFIX "%s", pci_name(port)); + if (!name) + return ERR_PTR(-ENOMEM); + + return thermal_cooling_device_register(name, port, &pcie_cooling_ops); +} + +void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev) +{ + thermal_cooling_device_unregister(cdev); +} + +/* For bus_speed <-> state arithmetic */ +static_assert(PCIE_SPEED_2_5GT + 1 == PCIE_SPEED_5_0GT); +static_assert(PCIE_SPEED_5_0GT + 1 == PCIE_SPEED_8_0GT); +static_assert(PCIE_SPEED_8_0GT + 1 == PCIE_SPEED_16_0GT); +static_assert(PCIE_SPEED_16_0GT + 1 == PCIE_SPEED_32_0GT); +static_assert(PCIE_SPEED_32_0GT + 1 == PCIE_SPEED_64_0GT); + +MODULE_AUTHOR("Ilpo Järvinen "); +MODULE_DESCRIPTION("PCIe cooling driver"); diff --git a/include/linux/pci-bwctrl.h b/include/linux/pci-bwctrl.h new file mode 100644 index 000000000000..cee07127455b --- /dev/null +++ b/include/linux/pci-bwctrl.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * PCIe bandwidth controller + * + * Copyright (C) 2023-2024 Intel Corporation + */ + +#ifndef LINUX_PCI_BWCTRL_H +#define LINUX_PCI_BWCTRL_H + +#include + +struct thermal_cooling_device; 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a="24257224" X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="24257224" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:29:15 -0700 X-CSE-ConnectionGUID: PtY63CttSpCsyit5dQ7H3g== X-CSE-MsgGUID: 4fq+/sfzSd6T1DFGXU1F6Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,217,1719903600"; d="scan'208";a="104483233" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.245.224]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 05:29:07 -0700 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-pci@vger.kernel.org, Bjorn Helgaas , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Maciej W. Rozycki" , Jonathan Cameron , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , Shuah Khan , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET Subject: [PATCH v7 8/8] selftests/pcie_bwctrl: Create selftests Date: Tue, 10 Sep 2024 15:27:05 +0300 Message-Id: <20240910122705.4068-9-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> References: <20240910122705.4068-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Create selftests for PCIe BW control through the PCIe cooling device sysfs interface. First, the BW control selftest finds the PCIe Port to test with. By default, the PCIe Port with the highest Link Speed is selected but another PCIe Port can be provided with -d parameter. The actual test steps the cur_state of the cooling device one-by-one from max_state to what the cur_state was initially. The speed change is confirmed by observing the current_link_speed for the corresponding PCIe Port. Signed-off-by: Ilpo Järvinen --- MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/pcie_bwctrl/Makefile | 2 + .../pcie_bwctrl/set_pcie_cooling_state.sh | 122 ++++++++++++++++++ .../selftests/pcie_bwctrl/set_pcie_speed.sh | 67 ++++++++++ 5 files changed, 193 insertions(+) create mode 100644 tools/testing/selftests/pcie_bwctrl/Makefile create mode 100755 tools/testing/selftests/pcie_bwctrl/set_pcie_cooling_state.sh create mode 100755 tools/testing/selftests/pcie_bwctrl/set_pcie_speed.sh diff --git a/MAINTAINERS b/MAINTAINERS index 47542dcb9259..dc601dcab8c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17676,6 +17676,7 @@ S: Supported F: drivers/pci/pcie/bwctrl.c F: drivers/thermal/pcie_cooling.c F: include/linux/pci-bwctrl.h +F: tools/testing/selftests/pcie_bwctrl/ PCIE DRIVER FOR AMAZON ANNAPURNA LABS M: Jonathan Chocron diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index bc8fe9e8f7f2..086af950930c 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -69,6 +69,7 @@ TARGETS += net/openvswitch TARGETS += net/tcp_ao TARGETS += net/netfilter TARGETS += nsfs +TARGETS += pcie_bwctrl TARGETS += perf_events TARGETS += pidfd TARGETS += pid_namespace diff --git a/tools/testing/selftests/pcie_bwctrl/Makefile b/tools/testing/selftests/pcie_bwctrl/Makefile new file mode 100644 index 000000000000..3e84e26341d1 --- /dev/null +++ b/tools/testing/selftests/pcie_bwctrl/Makefile @@ -0,0 +1,2 @@ +TEST_PROGS = set_pcie_cooling_state.sh +include ../lib.mk diff --git a/tools/testing/selftests/pcie_bwctrl/set_pcie_cooling_state.sh b/tools/testing/selftests/pcie_bwctrl/set_pcie_cooling_state.sh new file mode 100755 index 000000000000..9df606552af3 --- /dev/null +++ b/tools/testing/selftests/pcie_bwctrl/set_pcie_cooling_state.sh @@ -0,0 +1,122 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later + +SYSFS= +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 +retval=0 +skipmsg="skip all tests:" + +PCIEPORTTYPE="PCIe_Port_Link_Speed" + +prerequisite() +{ + local ports + + if [ $UID != 0 ]; then + echo $skipmsg must be run as root >&2 + exit $ksft_skip + fi + + SYSFS=`mount -t sysfs | head -1 | awk '{ print $3 }'` + + if [ ! -d "$SYSFS" ]; then + echo $skipmsg sysfs is not mounted >&2 + exit $ksft_skip + fi + + if ! ls $SYSFS/class/thermal/cooling_device* > /dev/null 2>&1; then + echo $skipmsg thermal cooling devices missing >&2 + exit $ksft_skip + fi + + ports=`grep -e "^$PCIEPORTTYPE" $SYSFS/class/thermal/cooling_device*/type | wc -l` + if [ $ports -eq 0 ]; then + echo $skipmsg pcie cooling devices missing >&2 + exit $ksft_skip + fi +} + +testport= +find_pcie_port() +{ + local patt="$1" + local pcieports + local max + local cur + local delta + local bestdelta=-1 + + pcieports=`grep -l -F -e "$patt" /sys/class/thermal/cooling_device*/type` + if [ -z "$pcieports" ]; then + return + fi + pcieports=${pcieports//\/type/} + # Find the port with the highest PCIe Link Speed + for port in $pcieports; do + max=`cat $port/max_state` + cur=`cat $port/cur_state` + delta=$((max-cur)) + if [ $delta -gt $bestdelta ]; then + testport="$port" + bestdelta=$delta + fi + done +} + +sysfspcidev= +find_sysfs_pci_dev() +{ + local typefile="$1/type" + local pcidir + + pcidir="$SYSFS/bus/pci/devices/`sed -e "s|^${PCIEPORTTYPE}_||g" $typefile`" + + if [ -r "$pcidir/current_link_speed" ]; then + sysfspcidev="$pcidir/current_link_speed" + fi +} + +usage() +{ + echo "Usage $0 [ -d dev ]" + echo -e "\t-d: PCIe port BDF string (e.g., 0000:00:04.0)" +} + +pattern="$PCIEPORTTYPE" +parse_arguments() +{ + while getopts d:h opt; do + case $opt in + h) + usage "$0" + exit 0 + ;; + d) + pattern="$PCIEPORTTYPE_$OPTARG" + ;; + *) + usage "$0" + exit 0 + ;; + esac + done +} + +parse_arguments "$@" +prerequisite +find_pcie_port "$pattern" +if [ -z "$testport" ]; then + echo $skipmsg "pcie cooling device not found from sysfs" >&2 + exit $ksft_skip +fi +find_sysfs_pci_dev "$testport" +if [ -z "$sysfspcidev" ]; then + echo $skipmsg "PCIe port device not found from sysfs" >&2 + exit $ksft_skip +fi + +./set_pcie_speed.sh "$testport" "$sysfspcidev" +retval=$? + +exit $retval diff --git a/tools/testing/selftests/pcie_bwctrl/set_pcie_speed.sh b/tools/testing/selftests/pcie_bwctrl/set_pcie_speed.sh new file mode 100755 index 000000000000..584596949312 --- /dev/null +++ b/tools/testing/selftests/pcie_bwctrl/set_pcie_speed.sh @@ -0,0 +1,67 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later + +set -e + +TESTNAME=set_pcie_speed + +declare -a PCIELINKSPEED=( + "2.5 GT/s PCIe" + "5.0 GT/s PCIe" + "8.0 GT/s PCIe" + "16.0 GT/s PCIe" + "32.0 GT/s PCIe" + "64.0 GT/s PCIe" +) + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 +retval=0 + +coolingdev="$1" +statefile="$coolingdev/cur_state" +maxfile="$coolingdev/max_state" +linkspeedfile="$2" + +oldstate=`cat $statefile` +maxstate=`cat $maxfile` + +set_state() +{ + local state=$1 + local linkspeed + local expected_linkspeed + + echo $state > $statefile + + sleep 1 + + linkspeed="`cat $linkspeedfile`" + expected_linkspeed=$((maxstate-state)) + expected_str="${PCIELINKSPEED[$expected_linkspeed]}" + if [ ! "${expected_str}" = "${linkspeed}" ]; then + echo "$TESTNAME failed: expected: ${expected_str}; got ${linkspeed}" + retval=1 + fi +} + +cleanup_skip () +{ + set_state $oldstate + exit $ksft_skip +} + +trap cleanup_skip EXIT + +echo "$TESTNAME: testing states $maxstate .. $oldstate with $coolingdev" +for i in $(seq $maxstate -1 $oldstate); do + set_state "$i" +done + +trap EXIT +if [ $retval -eq 0 ]; then + echo "$TESTNAME [PASS]" +else + echo "$TESTNAME [FAIL]" +fi +exit $retval