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// SPDX-License-Identifier: GPL-2.0-only
/*
* PCIe cooling device
*
* Copyright (C) 2023-2024 Intel Corporation
*/
#include <linux/build_bug.h>
#include <linux/cleanup.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci-bwctrl.h>
#include <linux/slab.h>
#include <linux/sprintf.h>
#include <linux/thermal.h>
#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 <ilpo.jarvinen@linux.intel.com>");
MODULE_DESCRIPTION("PCIe cooling driver");
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