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Wysocki" , linux-pm@vger.kernel.org, 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 v5 1/8] PCI: Protect Link Control 2 Register with RMW locking Date: Wed, 8 May 2024 16:47:37 +0300 Message-Id: <20240508134744.52134-2-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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 a0027e8fb0d0..cd7857dd37aa 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 16493426a04f..93faaf08965e 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1273,6 +1273,7 @@ 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 Wed May 8 13:47:38 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: 795644 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) (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 374C31A2C11; Wed, 8 May 2024 13:48:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176113; cv=none; b=JXIzOL31D4KCSYwDYnfgvyrfRtOOxUZTy5v0j2SqEmRGpGptUAtOJRIW/CWRJd5pUXS9VwGY+CJL7UNIcrG6UHHL9a2wpcjyE9njOtqKCnD7JOmm8uZUCBCVYXsy2o1zBxOXrWMwFc5eib/HW6hbixr02oYfhhMhEH7xO1TTsIE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176113; c=relaxed/simple; bh=vTjJi8RrIHlRsAWN1AG4hbmf9M558XDjrEdnmS2bFMo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=Lee+HATbnBvLOb4mDZTx7wGCW6JmWRjOX3GCoIraX5c8g6c2OMsNvTZDvkG/+iRlH1MFH47tu4uhgg+PRAdT1MW2gcT5VWAMfmQ4N1KqsAamY+e0KaiXqm3yVz3n4738mYCcvWK6H9az+fhTEdGvx8oVZ0TARR3eE+97qVGo+Sc= 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=e+IGjsYm; arc=none smtp.client-ip=192.198.163.17 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="e+IGjsYm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1715176112; x=1746712112; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=vTjJi8RrIHlRsAWN1AG4hbmf9M558XDjrEdnmS2bFMo=; b=e+IGjsYmt7p0mEU62q7n31SLKe6FPkncVYXhsfKJIzH53d0Kw5BfRy0F WUjbrJDsxTj7/0Aax49rTDaxuyj9wrGQNbQI7RpXBTyG3jhYeASnx5BdM PW1IoCQklKpyymIAvUEFYbfYntzABTS6rU9Ukw4dNCMQ5O3yIjSaz2E2h QZgHklyUdqrs5UKWXPGLhbTirCz8a26kGKPEjgq5lwUuSE+x5jg5RvsHn Nj/7tw8G9j8KidrVSjaCVaBbHIc56FxW/MPgrVufkQ379S2Q+jyW2MF4N 0cIQnzhRGwnN/N24JOTdyjHXFSScb4bU0ytA/AjwIiQTe30bwVTpBwhg5 w==; X-CSE-ConnectionGUID: 1jRZVnZPR4+vIADuG8qexw== X-CSE-MsgGUID: 6rXWvVdaTZCzgq/K4+YO9w== X-IronPort-AV: E=McAfee;i="6600,9927,11066"; a="10906428" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="10906428" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:31 -0700 X-CSE-ConnectionGUID: AmSHJzQLRuqnDWkGaf0w9A== X-CSE-MsgGUID: BXvpLrrLSQCWRGPyVjjh9Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28855196" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:26 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@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 v5 2/8] PCI: Store all PCIe Supported Link Speeds Date: Wed, 8 May 2024 16:47:38 +0300 Message-Id: <20240508134744.52134-3-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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_bus that caches the intersection of the upstream and downstream Supported Link Speeds Vectors. When the Function 0 is enumerated, calculate the intersection and set supported_speeds (as per PCIe r6.1 sec 7.5.3.18, the Multi-Function Devices must have the same speeds for all Functions). If no Upstream Port or Endpoint exists, supported_speeds is set to 2.5GT/s. 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. Suggested-by: Lukas Wunner Signed-off-by: Ilpo Järvinen --- drivers/pci/pci.c | 59 ++++++++++++++++++++++++----------- drivers/pci/probe.c | 8 +++++ drivers/pci/remove.c | 3 ++ include/linux/pci.h | 10 ++++++ include/uapi/linux/pci_regs.h | 1 + 5 files changed, 63 insertions(+), 18 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 55a5644393d6..77c13839c815 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6002,38 +6002,61 @@ 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; +} +EXPORT_SYMBOL_GPL(pcie_get_supported_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(pcie_get_supported_speeds(dev)); } EXPORT_SYMBOL(pcie_get_speed_cap); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 1325fbae2f28..1b08b3f16027 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -831,6 +831,8 @@ static void pci_set_bus_speed(struct pci_bus *bus) pcie_capability_read_dword(bridge, PCI_EXP_LNKCAP, &linkcap); bus->max_bus_speed = pcie_link_speed[linkcap & PCI_EXP_LNKCAP_SLS]; + if (bus->max_bus_speed != PCI_SPEED_UNKNOWN) + bus->supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB; pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); pcie_update_link_speed(bus, linksta); @@ -2532,6 +2534,7 @@ static void pci_set_msi_domain(struct pci_dev *dev) void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) { + u8 speeds = 0; int ret; pci_configure_device(dev); @@ -2558,11 +2561,16 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) pci_init_capabilities(dev); + if (bus->self && pci_is_pcie(dev) && PCI_FUNC(dev->devfn) == 0) { + speeds = pcie_get_supported_speeds(bus->self) & + pcie_get_supported_speeds(dev); + } /* * Add the device to our list of discovered devices * and the bus list for fixup functions, etc. */ down_write(&pci_bus_sem); + bus->supported_speeds = speeds; list_add_tail(&dev->bus_list, &bus->devices); up_write(&pci_bus_sem); diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c index d749ea8250d6..c492527e994a 100644 --- a/drivers/pci/remove.c +++ b/drivers/pci/remove.c @@ -36,6 +36,9 @@ static void pci_destroy_dev(struct pci_dev *dev) device_del(&dev->dev); down_write(&pci_bus_sem); + if (pci_is_pcie(dev) && PCI_FUNC(dev->devfn) == 0 && + dev->bus->max_bus_speed != PCI_SPEED_UNKNOWN) + dev->bus->supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB; list_del(&dev->bus_list); up_write(&pci_bus_sem); diff --git a/include/linux/pci.h b/include/linux/pci.h index 93faaf08965e..ca06a60d4dd3 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); @@ -644,6 +645,14 @@ struct pci_bus_resource { #define PCI_REGION_FLAG_MASK 0x0fU /* These bits of resource flags tell us the PCI region flags */ +/* + * @supported_speeds: PCIe Supported Link Speeds Vector (+ reserved 0 at + * LSB). Combination of downstream and upstream + * Supported Link Speeds Vectors. 0 when speed cannot + * be determined (e.g., for Root Complex Integrated + * Endpoints without the relevant Capability + * Registers). + */ struct pci_bus { struct list_head node; /* Node in list of buses */ struct pci_bus *parent; /* Parent bus this bridge is on */ @@ -664,6 +673,7 @@ struct pci_bus { unsigned char primary; /* Number of primary bridge */ unsigned char max_bus_speed; /* enum pci_bus_speed */ unsigned char cur_bus_speed; /* enum pci_bus_speed */ + u8 supported_speeds; /* Supported Link Speeds Vector */ #ifdef CONFIG_PCI_DOMAINS_GENERIC int domain_nr; #endif diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index a39193213ff2..7f929e04222b 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 Wed May 8 13:47:39 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: 795999 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) (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 5CD877D3F5; Wed, 8 May 2024 13:48:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176125; cv=none; b=Bl8RJnWLY7p9w8nPWPK8QaMaJVMXTWbUf+rPSUe03QIdwP8QBeNjeOJyBz+stIe/7zLM75HpMaS1or09Kb67wxg2HS9AGJNXUpU1UopomIVjbodTEo1YdD1bNcvYLn/sBNvMAdlsb1ju0c9S8/uptIsNER1tM8APg25aeIvvT4A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176125; c=relaxed/simple; bh=BVjR8kQOCaRR8HeUse8J/wqXd6QjtOPOLht8xEyki8E=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=ZqAXH/QwPlxZLHU1uhOSF8HRNGYKds3pkZXCDKZAY5dSVrkS4v1wtOzkRhuVo+6aVySSGrmk8P9+IovenusUMma4E9pcW7O2h9bmwM5uVJLyJmu+8vJR59ixJEu17j69mypyvGgHHHG4iiBvxZqpVqw64ZTDxYLH8CQzuLEzPOs= 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=LYkBkqYI; arc=none smtp.client-ip=192.198.163.17 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="LYkBkqYI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1715176124; x=1746712124; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=BVjR8kQOCaRR8HeUse8J/wqXd6QjtOPOLht8xEyki8E=; b=LYkBkqYImGbz95aSARmlH07FGHUakWxsJhG57RAYeSq5PNSJepXLt9Fq 1Hi+bqBiMDbl2ZuuztE590ELNeGYfno3XVecknnnzmb0Q06r7d68rWpuI H57WiSuU0TZ51yQmM/3443abv+rgfF16yR5Qlrb+OR/W8VrY+ABRTVdgn EhKhduNgfoOGDk/6dT8nfuim+Cu83N+5mijI7qJhggvWcl6Ms+Shggfza t4f7RhU0YjOb8p4AqqRBcWYPWWkj5klfMKk5foNfWMUdO5Op7cEGJIpN8 FDCnvFRwzqdeiFpnxsGObWP+wbgS6OKH39dMEY+b+/47D9l4cTRkG+fNj w==; X-CSE-ConnectionGUID: W313VmFdRbKHV/U+4zGbzA== X-CSE-MsgGUID: mODxGbbGQTygbBJvGlN/PA== X-IronPort-AV: E=McAfee;i="6600,9927,11066"; a="10906472" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="10906472" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:43 -0700 X-CSE-ConnectionGUID: i4G4k7+1QrGSuJ7/+wgkyQ== X-CSE-MsgGUID: QuTuY6MET6ydnjbFeVpomw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="29474896" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:37 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@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 v5 3/8] PCI: Refactor pcie_update_link_speed() Date: Wed, 8 May 2024 16:47:39 +0300 Message-Id: <20240508134744.52134-4-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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 into pcie_update_link_speed() 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 b1d0a1b3917d..0d818110af6d 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 48eae81a0a43..664191768395 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -297,7 +297,12 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, enum pcie_link_width *width); 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 1b08b3f16027..65413d408b3d 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); @@ -827,15 +831,13 @@ 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]; if (bus->max_bus_speed != PCI_SPEED_UNKNOWN) bus->supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB; - pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta); - pcie_update_link_speed(bus, linksta); + pcie_update_link_speed(bus); } } From patchwork Wed May 8 13:47:40 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: 795998 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (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 5A02684DED; Wed, 8 May 2024 13:48:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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a="28512703" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28512703" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:54 -0700 X-CSE-ConnectionGUID: iGvG/qzBTPOYPi9dRB9yWg== X-CSE-MsgGUID: YSi+KxecRQuYsBropfuoeA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28983288" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:48:48 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@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 v5 4/8] PCI/quirks: Abstract LBMS seen check into own function Date: Wed, 8 May 2024 16:47:40 +0300 Message-Id: <20240508134744.52134-5-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The 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 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 2ae06c7b1917..9be942623573 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. * @@ -92,8 +97,7 @@ 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)) { pci_info(dev, "broken device, retraining non-functional downstream link at 2.5GT/s\n"); lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; From patchwork Wed May 8 13:47:41 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: 795643 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (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 80A6984E10; Wed, 8 May 2024 13:49:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176147; cv=none; b=mOKOKhmSi1P54ukle/lUpVTRWm7lieFc+BsqHKRU/dbSuhAKCuDgIt4fxESuDxxLc46laH8JfQ7zoXNZB6OPoGu8i+Kuu0Ix5FOjNXrPF2J1Ud0UO07jfZwqa/eL9F839hy/DHT3+kuRaSHRo9DgfozSRB3d5bhJsj1U+QRVSRw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176147; c=relaxed/simple; bh=xMnbfMG6UmzXbuF6YbxMeVAejwYiEOepI7+TGS2R2lk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=mGE88Ymkflwe1SQRuIWVsk6d6sSvDfamnL/oPwhN+Vnc4VYzkUCIwCwvHJc0gVYsPnE3iZ5KFHhuoS6SHtQ71sZ5F8JA2f8EDyWUd4U6X5Mt6dIgb4SlBSQJGBN0sa7QDECSJVqOm4qYURK9wv0m4KVBltJ40xCcaxBEPymyw6w= 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=fBjZRZgN; arc=none smtp.client-ip=198.175.65.10 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="fBjZRZgN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1715176145; x=1746712145; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=xMnbfMG6UmzXbuF6YbxMeVAejwYiEOepI7+TGS2R2lk=; b=fBjZRZgNUD0XQrXejB/scFqirSrSELVTnWjvc6BzFIMZUNC8g34YWQ3D YqMBdVVobhSVP9aIWILtM7FXRIOVGdwEw4b7BPJEgMP8vo52oc0AFvKac 7mFld5soX95zRzl9tAO1c+Z9b9dXfCPTy/CRQqpwpwshjb/yNmUOTSt85 mops5hI5HZWDS7M2BTxOtSsSO8FXCd1Fde0mCPOi3K8KYjd3pcFiCPYy3 q0kKwe4nUu4y/A/fM4iT2bS40qGf3egOei4H6oVEPWV8YRxovfZ+oUaiX v59ZHH1s4dg9++NN+7qnYQNdpM9f80XgqRF6hkmZrSaxyxmQxk37GU5ga g==; X-CSE-ConnectionGUID: lZl1aPcjSXaUcoMGM+6ORQ== X-CSE-MsgGUID: gBa6DYFFQKOzSkpHcHQRYg== X-IronPort-AV: E=McAfee;i="6600,9927,11066"; a="28512762" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28512762" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:05 -0700 X-CSE-ConnectionGUID: q++t7zISRcqjDW17LK/ubQ== X-CSE-MsgGUID: +YwBOEczQSmAJYzWTtoHcQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28983324" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:00 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET Subject: [PATCH v5 5/8] PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller Date: Wed, 8 May 2024 16:47:41 +0300 Message-Id: <20240508134744.52134-6-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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_pci.c | 2 + drivers/pci/pci.h | 11 ++ drivers/pci/pcie/Kconfig | 12 ++ drivers/pci/pcie/Makefile | 1 + drivers/pci/pcie/bwctrl.c | 185 +++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv.c | 9 +- drivers/pci/pcie/portdrv.h | 10 +- drivers/pci/quirks.c | 7 +- include/linux/pci.h | 4 + 10 files changed, 240 insertions(+), 7 deletions(-) create mode 100644 drivers/pci/pcie/bwctrl.c diff --git a/MAINTAINERS b/MAINTAINERS index aa3b947fb080..bd420cb09821 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17099,6 +17099,12 @@ 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_pci.c b/drivers/pci/hotplug/pciehp_pci.c index ad12515a4a12..406d77d76310 100644 --- a/drivers/pci/hotplug/pciehp_pci.c +++ b/drivers/pci/hotplug/pciehp_pci.c @@ -133,5 +133,7 @@ void pciehp_unconfigure_device(struct controller *ctrl, bool presence) pci_dev_put(dev); } + pcie_reset_lbms_count(ctrl->pcie->port); + pci_unlock_rescan_remove(); } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 664191768395..416540baf27b 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -608,6 +608,17 @@ 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); +#else +static inline void pcie_reset_lbms_count(struct pci_dev *port) { } +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 8999fcebde6a..6dff10332a13 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..5afc533dd0a9 --- /dev/null +++ b/drivers/pci/pcie/bwctrl.c @@ -0,0 +1,185 @@ +// 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); + events = link_status & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_LABS); + + if (ret != PCIBIOS_SUCCESSFUL || !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); +} + +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_info(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); + + scoped_guard(rwsem_write, &pcie_bwctrl_remove_rwsem) + srv->port->link_bwctrl = NULL; + + pcie_bwnotif_disable(srv->port); + 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 14a4b89a3b83..e8a348949d70 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; @@ -829,6 +829,7 @@ static void __init pcie_init_services(void) pcie_pme_init(); pcie_dpc_init(); pcie_hp_init(); + pcie_bwctrl_init(); } static int __init pcie_portdrv_init(void) 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 9be942623573..d916aa2f2f4d 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -35,7 +35,12 @@ static bool pcie_lbms_seen(struct pci_dev *dev, u16 lnksta) { - return lnksta & PCI_EXP_LNKSTA_LBMS; + unsigned long count; + + if (pcie_lbms_count(dev, &count) < 0) + return lnksta & PCI_EXP_LNKSTA_LBMS; + + return count > 0; } /* diff --git a/include/linux/pci.h b/include/linux/pci.h index ca06a60d4dd3..406ed87fb0aa 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; @@ -494,6 +495,9 @@ 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 Wed May 8 13:47:42 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: 795997 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (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 7F46685281; Wed, 8 May 2024 13:49:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715176158; cv=none; b=BIeJAD1xUTCPknNUBJLLkEMiC+1yubd/ASjOvepMoOiIAQD1Bfys9ZnZ9oZtkeWcIHEhwva+84ApR55u56wsEiPwHKAcZUoSsJPOEfPv88zB68i83WxYky7Yly5O52Wyswf6kz13K7hISls9HRTxIa/GOUolk/WDVF+cQQFxSyU= ARC-Message-Signature: i=1; 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d="scan'208";a="28983481" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:10 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-kernel@vger.kernel.org Cc: Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET Subject: [PATCH v5 6/8] PCI/bwctrl: Add API to set PCIe Link Speed Date: Wed, 8 May 2024 16:47:42 +0300 Message-Id: <20240508134744.52134-7-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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 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 | 13 ++++ drivers/pci/pcie/Makefile | 2 +- drivers/pci/pcie/bwctrl.c | 147 ++++++++++++++++++++++++++++++++++++++ drivers/pci/quirks.c | 12 +--- include/linux/pci.h | 3 + 5 files changed, 166 insertions(+), 11 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 416540baf27b..324899fbad0a 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -270,6 +270,19 @@ 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) \ +({ \ + u32 _lnkcap = (lnkcap) & PCI_EXP_LNKCAP_SLS; \ + \ + (_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 : \ 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 5afc533dd0a9..e97665848158 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 +36,151 @@ /** * 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; }; +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; + + if (WARN_ON_ONCE(!bus->supported_speeds)) + return PCI_EXP_LNKCAP2_SLS_2_5GB; + + desired_speeds = GENMASK(pci_bus_speed2lnkctl2(speed_req), + __fls(PCI_EXP_LNKCAP2_SLS_2_5GB)); + + return pcie_supported_speeds2target_speed(bus->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. + */ + pcie_update_link_speed(port->subordinate); + + return 0; +} + +#ifdef CONFIG_PCIE_BWCTRL /* Prevents port removal during link speed changes and LBMS count accessors */ static DECLARE_RWSEM(pcie_bwctrl_remove_rwsem); +static int __pcie_set_target_speed(struct pci_dev *port, u16 target_speed, bool use_lt) +{ + struct pcie_bwctrl_data *data = NULL; + + guard(rwsem_read)(&pcie_bwctrl_remove_rwsem); + data = port->link_bwctrl; + if (!data) + return -ENODEV; + + guard(mutex)(&data->set_speed_mutex); + + return pcie_bwctrl_change_speed(port, target_speed, use_lt); +} +#else +static int __pcie_set_target_speed(struct pci_dev *port, u16 target_speed, bool use_lt) +{ + return pcie_bwctrl_change_speed(port, target_speed, use_lt); +} +#endif + +/** + * 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) +{ + u16 target_speed; + int ret; + + if (WARN_ON_ONCE(!pcie_valid_speed(speed_req))) + return -EINVAL; + + if (port->subordinate->cur_bus_speed == speed_req) + return 0; + + target_speed = pcie_bwctrl_select_speed(port, speed_req); + + ret = __pcie_set_target_speed(port, target_speed, use_lt); + if (!ret && port->subordinate->cur_bus_speed != speed_req) + 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); @@ -131,6 +275,7 @@ 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, @@ -154,6 +299,7 @@ static void pcie_bwnotif_remove(struct pcie_device *srv) pcie_bwnotif_disable(srv->port); free_irq(srv->irq, srv); + mutex_destroy(&data->set_speed_mutex); kfree(data); } @@ -183,3 +329,4 @@ 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 d916aa2f2f4d..673023c64a65 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -105,11 +105,7 @@ int pcie_failed_link_retrain(struct pci_dev *dev) if (!(lnksta & PCI_EXP_LNKSTA_DLLLA) && pcie_lbms_seen(dev, lnksta)) { 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"); return ret; @@ -125,11 +121,7 @@ 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 406ed87fb0aa..b43bbd61c437 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1876,6 +1876,9 @@ bool pci_aer_available(void); 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d="scan'208";a="28855368" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:25 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Daniel Lezcano , Zhang Rui , Lukasz Luba , linux-kernel@vger.kernel.org Cc: Amit Kucheria , Christophe JAILLET Subject: [PATCH v5 7/8] thermal: Add PCIe cooling driver Date: Wed, 8 May 2024 16:47:43 +0300 Message-Id: <20240508134744.52134-8-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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. The thermal side state 0 means no throttling, i.e., maximum supported PCIe Link Speed. Signed-off-by: Ilpo Järvinen Acked-by: Rafael J. Wysocki # From the cooling device interface perspective Reviewed-by: Jonathan Cameron --- MAINTAINERS | 2 + drivers/pci/pcie/bwctrl.c | 8 ++++ drivers/thermal/Kconfig | 10 ++++ drivers/thermal/Makefile | 2 + drivers/thermal/pcie_cooling.c | 84 ++++++++++++++++++++++++++++++++++ include/linux/pci-bwctrl.h | 28 ++++++++++++ 6 files changed, 134 insertions(+) create mode 100644 drivers/thermal/pcie_cooling.c create mode 100644 include/linux/pci-bwctrl.h diff --git a/MAINTAINERS b/MAINTAINERS index bd420cb09821..3a94ae81b13f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17104,6 +17104,8 @@ 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 e97665848158..5d1df9e6a349 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; }; static bool pcie_valid_speed(enum pci_bus_speed speed) @@ -287,6 +290,8 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) pcie_bwnotif_enable(srv); pci_info(port, "enabled with IRQ %d\n", srv->irq); + port->link_bwctrl->cdev = pcie_cooling_device_register(port); + return 0; } @@ -294,6 +299,9 @@ 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); + scoped_guard(rwsem_write, &pcie_bwctrl_remove_rwsem) srv->port->link_bwctrl = NULL; diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 204ed89a3ec9..7ddc44be4701 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 5cdf7d68687f..5b9bf8e80eb6 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..367290d57e99 --- /dev/null +++ b/drivers/thermal/pcie_cooling.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PCIe cooling device + * + * Copyright (C) 2023 Intel Corporation + */ + +#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) +{ + struct thermal_cooling_device *cdev; + char *name; + + name = kasprintf(GFP_KERNEL, COOLING_DEV_TYPE_PREFIX "%s", pci_name(port)); + if (!name) + return ERR_PTR(-ENOMEM); + + cdev = thermal_cooling_device_register(name, port, &pcie_cooling_ops); + kfree(name); + + return cdev; +} + +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; + +#ifdef CONFIG_PCIE_THERMAL +struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port); +void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev); +#else +static inline struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port) +{ + return NULL; +} +static inline void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev) +{ +} +#endif + +#endif From patchwork Wed May 8 13:47:44 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: 795996 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) (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 81B321A2C11; Wed, 8 May 2024 13:49:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.17 ARC-Seal: i=1; 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a="10906704" X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="10906704" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:43 -0700 X-CSE-ConnectionGUID: YQXKHuBjRF2jRCIHJ8tR9w== X-CSE-MsgGUID: C7Lqb68eT8iGRXzNVoD2UA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,145,1712646000"; d="scan'208";a="28855409" Received: from ijarvine-desk1.ger.corp.intel.com (HELO localhost) ([10.245.247.80]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2024 06:49:37 -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?= , Lukas Wunner , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, 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 v5 8/8] selftests/pcie_bwctrl: Create selftests Date: Wed, 8 May 2024 16:47:44 +0300 Message-Id: <20240508134744.52134-9-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> References: <20240508134744.52134-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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 3a94ae81b13f..5a3b69515256 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17106,6 +17106,7 @@ 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 e1504833654d..ac0bc8af4123 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -65,6 +65,7 @@ TARGETS += net/openvswitch TARGETS += net/tcp_ao TARGETS += 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