1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Processor thermal device module for registering and processing
4  * power floor. When the hardware reduces the power to the minimum
5  * possible, the power floor is notified via an interrupt.
6  *
7  * Operation:
8  * When user space enables power floor reporting:
9  * - Use mailbox to:
10  *	Enable processor thermal device interrupt
11  *
12  * - Current status of power floor is read from offset 0x5B18
13  *   bit 39.
14  *
15  * Two interface functions are provided to call when there is a
16  * thermal device interrupt:
17  * - proc_thermal_power_floor_intr():
18  *	Check if the interrupt is for change in power floor.
19  *	Called from interrupt context.
20  *
21  * - proc_thermal_power_floor_intr_callback():
22  *	Callback for interrupt processing in thread context. This involves
23  *	sending notification to user space that there is a change in the
24  *	power floor status.
25  *
26  * Copyright (c) 2023, Intel Corporation.
27  */
28 
29 #include <linux/pci.h>
30 #include "processor_thermal_device.h"
31 
32 #define SOC_POWER_FLOOR_STATUS		BIT(39)
33 #define SOC_POWER_FLOOR_SHIFT		39
34 
35 #define SOC_POWER_FLOOR_INT_ENABLE_BIT	31
36 #define SOC_POWER_FLOOR_INT_ACTIVE	BIT(3)
37 
38 int proc_thermal_read_power_floor_status(struct proc_thermal_device *proc_priv)
39 {
40 	u64 status = 0;
41 
42 	status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
43 	return (status & SOC_POWER_FLOOR_STATUS) >> SOC_POWER_FLOOR_SHIFT;
44 }
45 EXPORT_SYMBOL_NS_GPL(proc_thermal_read_power_floor_status, "INT340X_THERMAL");
46 
47 static bool enable_state;
48 static DEFINE_MUTEX(pf_lock);
49 
50 int proc_thermal_power_floor_set_state(struct proc_thermal_device *proc_priv, bool enable)
51 {
52 	int ret = 0;
53 
54 	mutex_lock(&pf_lock);
55 	if (enable_state == enable)
56 		goto pf_unlock;
57 
58 	/*
59 	 * Time window parameter is not applicable to power floor interrupt configuration.
60 	 * Hence use -1 for time window.
61 	 */
62 	ret = processor_thermal_mbox_interrupt_config(to_pci_dev(proc_priv->dev), enable,
63 						      SOC_POWER_FLOOR_INT_ENABLE_BIT, -1);
64 	if (!ret)
65 		enable_state = enable;
66 
67 pf_unlock:
68 	mutex_unlock(&pf_lock);
69 
70 	return ret;
71 }
72 EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_set_state, "INT340X_THERMAL");
73 
74 bool proc_thermal_power_floor_get_state(struct proc_thermal_device *proc_priv)
75 {
76 	return enable_state;
77 }
78 EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_get_state, "INT340X_THERMAL");
79 
80 /**
81  * proc_thermal_check_power_floor_intr() - Check power floor interrupt.
82  * @proc_priv: Processor thermal device instance.
83  *
84  * Callback to check if the interrupt for power floor is active.
85  *
86  * Context: Called from interrupt context.
87  *
88  * Return: true if power floor is active, false when not active.
89  */
90 bool proc_thermal_check_power_floor_intr(struct proc_thermal_device *proc_priv)
91 {
92 	u64 int_status;
93 
94 	int_status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
95 	return !!(int_status & SOC_POWER_FLOOR_INT_ACTIVE);
96 }
97 EXPORT_SYMBOL_NS_GPL(proc_thermal_check_power_floor_intr, "INT340X_THERMAL");
98 
99 /**
100  * proc_thermal_power_floor_intr_callback() - Process power floor notification
101  * @pdev:	PCI device instance
102  * @proc_priv: Processor thermal device instance.
103  *
104  * Check if the power floor interrupt is active, if active send notification to
105  * user space for the attribute "power_limits", so that user can read the attribute
106  * and take action.
107  *
108  * Context: Called from interrupt thread context.
109  *
110  * Return: None.
111  */
112 void proc_thermal_power_floor_intr_callback(struct pci_dev *pdev,
113 					    struct proc_thermal_device *proc_priv)
114 {
115 	u64 status;
116 
117 	status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
118 	if (!(status & SOC_POWER_FLOOR_INT_ACTIVE))
119 		return;
120 
121 	sysfs_notify(&pdev->dev.kobj, "power_limits", "power_floor_status");
122 }
123 EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_intr_callback, "INT340X_THERMAL");
124 
125 MODULE_IMPORT_NS("INT340X_THERMAL");
126 MODULE_LICENSE("GPL");
127 MODULE_DESCRIPTION("Processor Thermal power floor notification Interface");
128