1 // SPDX-License-Identifier: GPL-2.0+
8  * Copyright (C) 2023-2024 Intel Corporation
30 #include <linux/pci-bwctrl.h>
39  * struct pcie_bwctrl_data - PCIe bandwidth controller
79  * pcie_bwctrl_select_speed - Select Target Link Speed
90 	struct pci_bus *bus = port->subordinate;  in pcie_bwctrl_select_speed()
97 	supported_speeds = port->supported_speeds;  in pcie_bwctrl_select_speed()
100 		dev = list_first_entry_or_null(&bus->devices, struct pci_dev, bus_list);  in pcie_bwctrl_select_speed()
102 			supported_speeds &= dev->supported_speeds;  in pcie_bwctrl_select_speed()
124  * pcie_set_target_speed - Set downstream Link Speed for PCIe Port
134  * * 0		- on success
135  * * -EINVAL	- @speed_req is not a PCIe Link Speed
136  * * -ENODEV	- @port is not controllable
137  * * -ETIMEDOUT	- changing Link Speed took too long
138  * * -EAGAIN	- Link Speed was changed but @speed_req was not achieved
143 	struct pci_bus *bus = port->subordinate;  in pcie_set_target_speed()
148 		return -EINVAL;  in pcie_set_target_speed()
150 	if (bus && bus->cur_bus_speed == speed_req)  in pcie_set_target_speed()
156 		struct pcie_bwctrl_data *data = port->link_bwctrl;  in pcie_set_target_speed()
159 		 * port->link_bwctrl is NULL during initial scan when called  in pcie_set_target_speed()
160 		 * e.g. from the Target Speed quirk.  in pcie_set_target_speed()
163 			mutex_lock(&data->set_speed_mutex);  in pcie_set_target_speed()
168 			mutex_unlock(&data->set_speed_mutex);  in pcie_set_target_speed()
175 	if (!ret && bus && bus->cur_bus_speed != speed_req &&  in pcie_set_target_speed()
176 	    !list_empty(&bus->devices))  in pcie_set_target_speed()
177 		ret = -EAGAIN;  in pcie_set_target_speed()
184 	struct pci_dev *port = srv->port;  in pcie_bwnotif_enable()
191 		set_bit(PCI_LINK_LBMS_SEEN, &port->priv_flags);  in pcie_bwnotif_enable()
199 	 * Update after enabling notifications & clearing status bits ensures  in pcie_bwnotif_enable()
202 	pcie_update_link_speed(port->subordinate);  in pcie_bwnotif_enable()
211 static irqreturn_t pcie_bwnotif_irq(int irq, void *context)  in pcie_bwnotif_irq()  argument
214 	struct pci_dev *port = srv->port;  in pcie_bwnotif_irq()
227 		set_bit(PCI_LINK_LBMS_SEEN, &port->priv_flags);  in pcie_bwnotif_irq()
233 	 * change until LBMS is cleared by the write. Therefore, re-read the  in pcie_bwnotif_irq()
237 	pcie_update_link_speed(port->subordinate);  in pcie_bwnotif_irq()
244 	clear_bit(PCI_LINK_LBMS_SEEN, &port->priv_flags);  in pcie_reset_lbms()
250 	struct pci_dev *port = srv->port;  in pcie_bwnotif_probe()
254 	if (!port->subordinate)  in pcie_bwnotif_probe()
255 		return -ENODEV;  in pcie_bwnotif_probe()
257 	struct pcie_bwctrl_data *data = devm_kzalloc(&srv->device,  in pcie_bwnotif_probe()
260 		return -ENOMEM;  in pcie_bwnotif_probe()
262 	ret = devm_mutex_init(&srv->device, &data->set_speed_mutex);  in pcie_bwnotif_probe()
267 		port->link_bwctrl = data;  in pcie_bwnotif_probe()
269 		ret = request_irq(srv->irq, pcie_bwnotif_irq,  in pcie_bwnotif_probe()
272 			port->link_bwctrl = NULL;  in pcie_bwnotif_probe()
279 	pci_dbg(port, "enabled with IRQ %d\n", srv->irq);  in pcie_bwnotif_probe()
281 	/* Don't fail on errors. Don't leave IS_ERR() "pointer" into ->cdev */  in pcie_bwnotif_probe()
282 	port->link_bwctrl->cdev = pcie_cooling_device_register(port);  in pcie_bwnotif_probe()
283 	if (IS_ERR(port->link_bwctrl->cdev))  in pcie_bwnotif_probe()
284 		port->link_bwctrl->cdev = NULL;  in pcie_bwnotif_probe()
291 	struct pcie_bwctrl_data *data = srv->port->link_bwctrl;  in pcie_bwnotif_remove()
293 	pcie_cooling_device_unregister(data->cdev);  in pcie_bwnotif_remove()
296 		pcie_bwnotif_disable(srv->port);  in pcie_bwnotif_remove()
298 		free_irq(srv->irq, srv);  in pcie_bwnotif_remove()
300 		srv->port->link_bwctrl = NULL;  in pcie_bwnotif_remove()
306 	pcie_bwnotif_disable(srv->port);  in pcie_bwnotif_suspend()