From 04af8a399fa40310f831b4f1dc9f757085f41983 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 18 Oct 2024 17:47:48 +0300 Subject: PCI: Protect Link Control 2 Register with RMW locking MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 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. Link: https://lore.kernel.org/r/20241018144755.7875-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Reviewed-by: Jonathan Cameron --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/pci.h b/include/linux/pci.h index 573b4c4c2be6..be5ed534c39c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1274,6 +1274,7 @@ 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); -- cgit v1.2.3 From d2bd39c0456b75be9dfc7d774b8d021355c26ae3 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 18 Oct 2024 17:47:49 +0300 Subject: PCI: Store all PCIe Supported Link Speeds MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 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 synthesized 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. Root Complex Integrated Endpoints do not have a well-defined Link Speed because they do not 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. The supported_speeds field keeps the extra reserved zero at the least significant bit to match the Link Capabilities 2 Register layout. An attempt was made to store supported_speeds field into the struct pci_bus as an intersection of 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 provided by the PCIe bandwidth controller 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 Link: https://lore.kernel.org/r/20241018144755.7875-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen [bhelgaas: move pcie_get_supported_speeds() decl to drivers/pci/pci.h] Signed-off-by: Bjorn Helgaas Reviewed-by: Jonathan Cameron --- drivers/pci/pci.c | 58 +++++++++++++++++++++++++++++++------------ drivers/pci/pci.h | 1 + drivers/pci/probe.c | 3 +++ include/linux/pci.h | 10 +++++++- include/uapi/linux/pci_regs.h | 1 + 5 files changed, 56 insertions(+), 17 deletions(-) (limited to 'include/linux') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7d85c04fbba2..3d67e8b50ba2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6189,38 +6189,64 @@ 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 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 synthesized + * from the Max Link Speed field in the Link Capabilities Register. + * + * Return: Supported Link Speeds Vector (+ reserved 0 at LSB). */ -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. + * Speeds retain the reserved 0 at LSB before PCIe Supported Link + * Speeds Vector to allow using SLS Vector bit defines directly. */ 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); + + /* Synthesize 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 PCI_SPEED_UNKNOWN; + return speeds; +} + +/** + * 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/pci.h b/drivers/pci/pci.h index 14d00ce45bfa..d0a46ecf7289 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -373,6 +373,7 @@ static inline int pcie_dev_speed_mbps(enum pci_bus_speed speed) return -EINVAL; } +u8 pcie_get_supported_speeds(struct pci_dev *dev); const char *pci_speed_string(enum pci_bus_speed speed); enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev); enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev); diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 4f68414c3086..af153a8e8225 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1947,6 +1947,9 @@ 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 be5ed534c39c..99c6fa30d25b 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -318,7 +318,14 @@ 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 */ @@ -522,6 +529,7 @@ struct pci_dev { struct npem *npem; /* Native PCIe Enclosure Management */ #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 12323b3334a9..f3c9de0a497c 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -678,6 +678,7 @@ #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 */ -- cgit v1.2.3 From 665745f274870c921020f610e2c99a3b1613519b Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 18 Oct 2024 17:47:52 +0300 Subject: PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. PCIe bandwidth notifications 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 in 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, also enable Link Autonomous Bandwidth Interrupt to cover the other source of bandwidth changes. 3) 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(). 4) Use concurrency safe LNKCTL RMW operations. 5) The driver is now called PCIe bwctrl (bandwidth controller) instead of just bandwidth notifications because of increased scope and functionality within the driver. 6) Coexist with the Target Link Speed quirk in pcie_failed_link_retrain(). Provide LBMS counting API for it. 7) 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. [bhelgaas: This is based on previous work by Alexandru Gagniuc ; see e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification")] Link: https://lore.kernel.org/r/20241018144755.7875-7-ilpo.jarvinen@linux.intel.com 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 [bhelgaas: squash fix to drop IRQF_ONESHOT and convert to hardirq handler: https://lore.kernel.org/r/20241115165717.15233-1-ilpo.jarvinen@linux.intel.com] Signed-off-by: Bjorn Helgaas Tested-by: Stefan Wahren Reviewed-by: Jonathan Cameron --- MAINTAINERS | 6 ++ drivers/pci/hotplug/pciehp_ctrl.c | 5 + drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 11 +++ drivers/pci/pcie/Makefile | 2 +- drivers/pci/pcie/bwctrl.c | 186 ++++++++++++++++++++++++++++++++++++++ drivers/pci/pcie/portdrv.c | 9 +- drivers/pci/pcie/portdrv.h | 6 +- drivers/pci/quirks.c | 9 +- include/linux/pci.h | 2 + 10 files changed, 229 insertions(+), 9 deletions(-) create mode 100644 drivers/pci/pcie/bwctrl.c (limited to 'include/linux') diff --git a/MAINTAINERS b/MAINTAINERS index c27f3190737f..8c555b3325d6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17933,6 +17933,12 @@ 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 3d67e8b50ba2..f85f380cdb9b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4740,7 +4740,7 @@ 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 8137ad2fead8..8ec189c8f3f5 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -698,6 +698,17 @@ static inline void pcie_set_ecrc_checking(struct pci_dev *dev) { } static inline void pcie_ecrc_get_policy(char *str) { } #endif +#ifdef CONFIG_PCIEPORTBUS +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/Makefile b/drivers/pci/pcie/Makefile index 6461aa93fe76..53ccab62314d 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -4,7 +4,7 @@ pcieportdrv-y := portdrv.o rcec.o -obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o +obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o bwctrl.o obj-y += aspm.o obj-$(CONFIG_PCIEAER) += aer.o err.o diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c new file mode 100644 index 000000000000..b3da24900271 --- /dev/null +++ b/drivers/pci/pcie/bwctrl.c @@ -0,0 +1,186 @@ +// 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 LBMS count accessors */ +static DECLARE_RWSEM(pcie_bwctrl_lbms_rwsem); + +static void pcie_bwnotif_enable(struct pcie_device *srv) +{ + struct pcie_bwctrl_data *data = srv->port->link_bwctrl; + 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(int irq, void *context) +{ + struct pcie_device *srv = context; + struct pcie_bwctrl_data *data = srv->port->link_bwctrl; + 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_lbms_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_lbms_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 = devm_kzalloc(&srv->device, + sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + ret = devm_request_irq(&srv->device, srv->irq, pcie_bwnotif_irq, + IRQF_SHARED, "PCIe bwctrl", srv); + if (ret) + return ret; + + scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) { + 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) +{ + pcie_bwnotif_disable(srv->port); + scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) + srv->port->link_bwctrl = NULL; +} + +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..bd29d1cc7b8b 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 +51,8 @@ int pcie_dpc_init(void); static inline int pcie_dpc_init(void) { return 0; } #endif +int pcie_bwctrl_init(void); + /* Port Type */ #define PCIE_ANY_PORT (~0) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index a560ea403b8e..e6d502dca939 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 99c6fa30d25b..579b28833429 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -313,6 +313,7 @@ struct pci_vpd { }; struct irq_affinity; +struct pcie_bwctrl_data; struct pcie_link_state; struct pci_sriov; struct pci_p2pdma; @@ -502,6 +503,7 @@ struct pci_dev { unsigned int dpc_rp_extensions:1; u8 dpc_rp_log_size; #endif + struct pcie_bwctrl_data *link_bwctrl; #ifdef CONFIG_PCI_ATS union { struct pci_sriov *sriov; /* PF: SR-IOV info */ -- cgit v1.2.3 From de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 18 Oct 2024 17:47:53 +0300 Subject: PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, PCIe Link Speeds are adjusted by custom code rather than in a common function provided in PCI core. The PCIe bandwidth controller (bwctrl) introduces an in-kernel API, pcie_set_target_speed(), 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, which requires the per port mutex (set_speed_mutex) to be only taken if the bwctrl setup is already complete. 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. Link: https://lore.kernel.org/r/20241018144755.7875-8-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen [bhelgaas: squash devm_mutex_init() error checking from https://lore.kernel.org/r/20241030163139.2111689-1-andriy.shevchenko@linux.intel.com, drop export of pcie_set_target_speed()] Signed-off-by: Bjorn Helgaas Reviewed-by: Jonathan Cameron --- drivers/pci/pci.h | 20 ++++++ drivers/pci/pcie/bwctrl.c | 180 ++++++++++++++++++++++++++++++++++++++++++++-- drivers/pci/quirks.c | 17 ++--- include/linux/pci.h | 10 +++ 4 files changed, 208 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 8ec189c8f3f5..7573f81f58c4 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -331,6 +331,17 @@ 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 : \ @@ -341,6 +352,15 @@ 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/bwctrl.c b/drivers/pci/pcie/bwctrl.c index b3da24900271..3cd3e2d066c9 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 @@ -28,14 +36,166 @@ /** * 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; }; -/* Prevents port removal during LBMS count accessors */ +/* + * Prevent port removal during LBMS count accessors and Link Speed changes. + * + * These have to be differentiated because pcie_bwctrl_change_speed() calls + * pcie_retrain_link() which uses LBMS count reset accessor on success + * (using just one rwsem triggers "possible recursive locking detected" + * warning). + */ static DECLARE_RWSEM(pcie_bwctrl_lbms_rwsem); +static DECLARE_RWSEM(pcie_bwctrl_setspeed_rwsem); + +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 + * + * Attempt 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); + + scoped_guard(rwsem_read, &pcie_bwctrl_setspeed_rwsem) { + struct pcie_bwctrl_data *data = port->link_bwctrl; + + /* + * port->link_bwctrl is NULL during initial scan when called + * e.g. from the Target Speed quirk. + */ + if (data) + mutex_lock(&data->set_speed_mutex); + + ret = pcie_bwctrl_change_speed(port, target_speed, use_lt); + + if (data) + mutex_unlock(&data->set_speed_mutex); + } + + /* + * 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; +} static void pcie_bwnotif_enable(struct pcie_device *srv) { @@ -136,14 +296,20 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) if (!data) return -ENOMEM; + ret = devm_mutex_init(&srv->device, &data->set_speed_mutex); + if (ret) + return ret; + ret = devm_request_irq(&srv->device, srv->irq, pcie_bwnotif_irq, IRQF_SHARED, "PCIe bwctrl", srv); if (ret) return ret; - scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) { - port->link_bwctrl = no_free_ptr(data); - pcie_bwnotif_enable(srv); + scoped_guard(rwsem_write, &pcie_bwctrl_setspeed_rwsem) { + scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) { + port->link_bwctrl = no_free_ptr(data); + pcie_bwnotif_enable(srv); + } } pci_dbg(port, "enabled with IRQ %d\n", srv->irq); @@ -154,8 +320,10 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) static void pcie_bwnotif_remove(struct pcie_device *srv) { pcie_bwnotif_disable(srv->port); - scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) - srv->port->link_bwctrl = NULL; + + scoped_guard(rwsem_write, &pcie_bwctrl_setspeed_rwsem) + scoped_guard(rwsem_write, &pcie_bwctrl_lbms_rwsem) + srv->port->link_bwctrl = NULL; } static int pcie_bwnotif_suspend(struct pcie_device *srv) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index e6d502dca939..dcf1c86a5488 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 579b28833429..4f02d9f91399 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1797,9 +1797,19 @@ static inline int pci_irqd_intx_xlate(struct irq_domain *d, #ifdef CONFIG_PCIEPORTBUS extern bool pcie_ports_disabled; extern bool pcie_ports_native; + +int pcie_set_target_speed(struct pci_dev *port, enum pci_bus_speed speed_req, + bool use_lt); #else #define pcie_ports_disabled true #define pcie_ports_native false + +static inline int pcie_set_target_speed(struct pci_dev *port, + enum pci_bus_speed speed_req, + bool use_lt) +{ + return -EOPNOTSUPP; +} #endif #define PCIE_LINK_STATE_L0S (BIT(0) | BIT(1)) /* Upstr/dwnstr L0s */ -- cgit v1.2.3 From d278b098282d1327f6e1be82aacb18457a4d244d Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Fri, 18 Oct 2024 17:47:54 +0300 Subject: thermal: Add PCIe cooling driver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Link: https://lore.kernel.org/r/20241018144755.7875-9-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen [bhelgaas: dropped data->cdev test per https://lore.kernel.org/r/ZzRm1SJTwEMRsAr8@wunner.de] Signed-off-by: Bjorn Helgaas Reviewed-by: Jonathan Cameron Acked-by: Rafael J. Wysocki # From the cooling device interface perspective --- MAINTAINERS | 2 ++ drivers/pci/pcie/bwctrl.c | 12 +++++++ drivers/thermal/Kconfig | 9 +++++ 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 (limited to 'include/linux') diff --git a/MAINTAINERS b/MAINTAINERS index 8c555b3325d6..393ed7ce5ea1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17938,6 +17938,8 @@ 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 3cd3e2d066c9..b59cacc740fa 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; }; /* @@ -314,11 +317,20 @@ 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; } static void pcie_bwnotif_remove(struct pcie_device *srv) { + struct pcie_bwctrl_data *data = srv->port->link_bwctrl; + + pcie_cooling_device_unregister(data->cdev); + pcie_bwnotif_disable(srv->port); scoped_guard(rwsem_write, &pcie_bwctrl_setspeed_rwsem) diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 61e7ae524b1f..d3f9686e26e7 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -220,6 +220,15 @@ config DEVFREQ_THERMAL If you want this support, you should say Y here. +config PCIE_THERMAL + bool "PCIe cooling support" + depends on PCIEPORTBUS + 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 41c4d56beb40..210c16c91461 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; + +#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 -- cgit v1.2.3