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// SPDX-License-Identifier: GPL-2.0-only
/*
* Processor thermal device module for registering and processing
* power floor. When the hardware reduces the power to the minimum
* possible, the power floor is notified via an interrupt.
*
* Operation:
* When user space enables power floor reporting:
* - Use mailbox to:
* Enable processor thermal device interrupt
*
* - Current status of power floor is read from offset 0x5B18
* bit 39.
*
* Two interface functions are provided to call when there is a
* thermal device interrupt:
* - proc_thermal_power_floor_intr():
* Check if the interrupt is for change in power floor.
* Called from interrupt context.
*
* - proc_thermal_power_floor_intr_callback():
* Callback for interrupt processing in thread context. This involves
* sending notification to user space that there is a change in the
* power floor status.
*
* Copyright (c) 2023, Intel Corporation.
*/
#include <linux/pci.h>
#include "processor_thermal_device.h"
#define SOC_POWER_FLOOR_STATUS BIT(39)
#define SOC_POWER_FLOOR_SHIFT 39
#define SOC_POWER_FLOOR_INT_ENABLE_BIT 31
#define SOC_POWER_FLOOR_INT_ACTIVE BIT(3)
int proc_thermal_read_power_floor_status(struct proc_thermal_device *proc_priv)
{
u64 status = 0;
status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
return (status & SOC_POWER_FLOOR_STATUS) >> SOC_POWER_FLOOR_SHIFT;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_read_power_floor_status, INT340X_THERMAL);
static bool enable_state;
static DEFINE_MUTEX(pf_lock);
int proc_thermal_power_floor_set_state(struct proc_thermal_device *proc_priv, bool enable)
{
int ret = 0;
mutex_lock(&pf_lock);
if (enable_state == enable)
goto pf_unlock;
/*
* Time window parameter is not applicable to power floor interrupt configuration.
* Hence use -1 for time window.
*/
ret = processor_thermal_mbox_interrupt_config(to_pci_dev(proc_priv->dev), enable,
SOC_POWER_FLOOR_INT_ENABLE_BIT, -1);
if (!ret)
enable_state = enable;
pf_unlock:
mutex_unlock(&pf_lock);
return ret;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_set_state, INT340X_THERMAL);
bool proc_thermal_power_floor_get_state(struct proc_thermal_device *proc_priv)
{
return enable_state;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_get_state, INT340X_THERMAL);
/**
* proc_thermal_check_power_floor_intr() - Check power floor interrupt.
* @proc_priv: Processor thermal device instance.
*
* Callback to check if the interrupt for power floor is active.
*
* Context: Called from interrupt context.
*
* Return: true if power floor is active, false when not active.
*/
bool proc_thermal_check_power_floor_intr(struct proc_thermal_device *proc_priv)
{
u64 int_status;
int_status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
return !!(int_status & SOC_POWER_FLOOR_INT_ACTIVE);
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_check_power_floor_intr, INT340X_THERMAL);
/**
* proc_thermal_power_floor_intr_callback() - Process power floor notification
* @pdev: PCI device instance
* @proc_priv: Processor thermal device instance.
*
* Check if the power floor interrupt is active, if active send notification to
* user space for the attribute "power_limits", so that user can read the attribute
* and take action.
*
* Context: Called from interrupt thread context.
*
* Return: None.
*/
void proc_thermal_power_floor_intr_callback(struct pci_dev *pdev,
struct proc_thermal_device *proc_priv)
{
u64 status;
status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
if (!(status & SOC_POWER_FLOOR_INT_ACTIVE))
return;
sysfs_notify(&pdev->dev.kobj, "power_limits", "power_floor_status");
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_power_floor_intr_callback, INT340X_THERMAL);
MODULE_IMPORT_NS(INT340X_THERMAL);
MODULE_LICENSE("GPL");
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