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d278b09828
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 <ilpo.jarvinen@linux.intel.com> [bhelgaas: dropped data->cdev test per https://lore.kernel.org/r/ZzRm1SJTwEMRsAr8@wunner.de] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Rafael J. Wysocki <rafael@kernel.org> # From the cooling device interface perspective
81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* PCIe cooling device
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*
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* Copyright (C) 2023-2024 Intel Corporation
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*/
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#include <linux/build_bug.h>
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#include <linux/cleanup.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/pci-bwctrl.h>
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#include <linux/slab.h>
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#include <linux/sprintf.h>
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#include <linux/thermal.h>
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#define COOLING_DEV_TYPE_PREFIX "PCIe_Port_Link_Speed_"
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static int pcie_cooling_get_max_level(struct thermal_cooling_device *cdev, unsigned long *state)
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{
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struct pci_dev *port = cdev->devdata;
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/* cooling state 0 is same as the maximum PCIe speed */
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*state = port->subordinate->max_bus_speed - PCIE_SPEED_2_5GT;
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return 0;
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}
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static int pcie_cooling_get_cur_level(struct thermal_cooling_device *cdev, unsigned long *state)
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{
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struct pci_dev *port = cdev->devdata;
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/* cooling state 0 is same as the maximum PCIe speed */
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*state = cdev->max_state - (port->subordinate->cur_bus_speed - PCIE_SPEED_2_5GT);
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return 0;
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}
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static int pcie_cooling_set_cur_level(struct thermal_cooling_device *cdev, unsigned long state)
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{
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struct pci_dev *port = cdev->devdata;
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enum pci_bus_speed speed;
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/* cooling state 0 is same as the maximum PCIe speed */
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speed = (cdev->max_state - state) + PCIE_SPEED_2_5GT;
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return pcie_set_target_speed(port, speed, true);
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}
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static struct thermal_cooling_device_ops pcie_cooling_ops = {
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.get_max_state = pcie_cooling_get_max_level,
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.get_cur_state = pcie_cooling_get_cur_level,
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.set_cur_state = pcie_cooling_set_cur_level,
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};
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struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port)
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{
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char *name __free(kfree) =
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kasprintf(GFP_KERNEL, COOLING_DEV_TYPE_PREFIX "%s", pci_name(port));
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if (!name)
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return ERR_PTR(-ENOMEM);
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return thermal_cooling_device_register(name, port, &pcie_cooling_ops);
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}
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void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev)
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{
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thermal_cooling_device_unregister(cdev);
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}
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/* For bus_speed <-> state arithmetic */
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static_assert(PCIE_SPEED_2_5GT + 1 == PCIE_SPEED_5_0GT);
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static_assert(PCIE_SPEED_5_0GT + 1 == PCIE_SPEED_8_0GT);
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static_assert(PCIE_SPEED_8_0GT + 1 == PCIE_SPEED_16_0GT);
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static_assert(PCIE_SPEED_16_0GT + 1 == PCIE_SPEED_32_0GT);
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static_assert(PCIE_SPEED_32_0GT + 1 == PCIE_SPEED_64_0GT);
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MODULE_AUTHOR("Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>");
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MODULE_DESCRIPTION("PCIe cooling driver");
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