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// SPDX-License-Identifier: GPL-2.0-only
/*
* processor thermal device interface for reading workload type hints
* from the user space. The hints are provided by the firmware.
*
* Operation:
* When user space enables workload type prediction:
* - Use mailbox to:
* Configure notification delay
* Enable processor thermal device interrupt
*
* - The predicted workload type can be read from MMIO:
* Offset 0x5B18 shows if there was an interrupt
* active for change in workload type and also
* predicted workload type.
*
* Two interface functions are provided to call when there is a
* thermal device interrupt:
* - proc_thermal_check_wt_intr():
* Check if the interrupt is for change in workload type. Called from
* interrupt context.
*
* - proc_thermal_wt_intr_callback():
* Callback for interrupt processing in thread context. This involves
* sending notification to user space that there is a change in the
* workload type.
*
* Copyright (c) 2023, Intel Corporation.
*/
#include <linux/bitfield.h>
#include <linux/pci.h>
#include "processor_thermal_device.h"
#define SOC_WT GENMASK_ULL(47, 40)
#define SOC_WT_PREDICTION_INT_ENABLE_BIT 23
#define SOC_WT_PREDICTION_INT_ACTIVE BIT(2)
/*
* Closest possible to 1 Second is 1024 ms with programmed time delay
* of 0x0A.
*/
static u8 notify_delay = 0x0A;
static u16 notify_delay_ms = 1024;
static DEFINE_MUTEX(wt_lock);
static u8 wt_enable;
/* Show current predicted workload type index */
static ssize_t workload_type_index_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct proc_thermal_device *proc_priv;
struct pci_dev *pdev = to_pci_dev(dev);
u64 status = 0;
int wt;
mutex_lock(&wt_lock);
if (!wt_enable) {
mutex_unlock(&wt_lock);
return -ENODATA;
}
proc_priv = pci_get_drvdata(pdev);
status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
mutex_unlock(&wt_lock);
wt = FIELD_GET(SOC_WT, status);
return sysfs_emit(buf, "%d\n", wt);
}
static DEVICE_ATTR_RO(workload_type_index);
static ssize_t workload_hint_enable_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%d\n", wt_enable);
}
static ssize_t workload_hint_enable_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pci_dev *pdev = to_pci_dev(dev);
u8 mode;
int ret;
if (kstrtou8(buf, 10, &mode) || mode > 1)
return -EINVAL;
mutex_lock(&wt_lock);
if (mode)
ret = processor_thermal_mbox_interrupt_config(pdev, true,
SOC_WT_PREDICTION_INT_ENABLE_BIT,
notify_delay);
else
ret = processor_thermal_mbox_interrupt_config(pdev, false,
SOC_WT_PREDICTION_INT_ENABLE_BIT, 0);
if (ret)
goto ret_enable_store;
ret = size;
wt_enable = mode;
ret_enable_store:
mutex_unlock(&wt_lock);
return ret;
}
static DEVICE_ATTR_RW(workload_hint_enable);
static ssize_t notification_delay_ms_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%u\n", notify_delay_ms);
}
static ssize_t notification_delay_ms_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct pci_dev *pdev = to_pci_dev(dev);
u16 new_tw;
int ret;
u8 tm;
/*
* Time window register value:
* Formula: (1 + x/4) * power(2,y)
* x = 2 msbs, that is [30:29] y = 5 [28:24]
* in INTR_CONFIG register.
* The result will be in milli seconds.
* Here, just keep x = 0, and just change y.
* First round up the user value to power of 2 and
* then take log2, to get "y" value to program.
*/
ret = kstrtou16(buf, 10, &new_tw);
if (ret)
return ret;
if (!new_tw)
return -EINVAL;
new_tw = roundup_pow_of_two(new_tw);
tm = ilog2(new_tw);
if (tm > 31)
return -EINVAL;
mutex_lock(&wt_lock);
/* If the workload hint was already enabled, then update with the new delay */
if (wt_enable)
ret = processor_thermal_mbox_interrupt_config(pdev, true,
SOC_WT_PREDICTION_INT_ENABLE_BIT,
tm);
if (!ret) {
ret = size;
notify_delay = tm;
notify_delay_ms = new_tw;
}
mutex_unlock(&wt_lock);
return ret;
}
static DEVICE_ATTR_RW(notification_delay_ms);
static struct attribute *workload_hint_attrs[] = {
&dev_attr_workload_type_index.attr,
&dev_attr_workload_hint_enable.attr,
&dev_attr_notification_delay_ms.attr,
NULL
};
static const struct attribute_group workload_hint_attribute_group = {
.attrs = workload_hint_attrs,
.name = "workload_hint"
};
/*
* Callback to check if the interrupt for prediction is active.
* Caution: Called from the interrupt context.
*/
bool proc_thermal_check_wt_intr(struct proc_thermal_device *proc_priv)
{
u64 int_status;
int_status = readq(proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
if (int_status & SOC_WT_PREDICTION_INT_ACTIVE)
return true;
return false;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_check_wt_intr, "INT340X_THERMAL");
/* Callback to notify user space */
void proc_thermal_wt_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_WT_PREDICTION_INT_ACTIVE))
return;
sysfs_notify(&pdev->dev.kobj, "workload_hint", "workload_type_index");
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_wt_intr_callback, "INT340X_THERMAL");
static bool workload_hint_created;
int proc_thermal_wt_hint_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv)
{
int ret;
ret = sysfs_create_group(&pdev->dev.kobj, &workload_hint_attribute_group);
if (ret)
return ret;
workload_hint_created = true;
return 0;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_wt_hint_add, "INT340X_THERMAL");
void proc_thermal_wt_hint_remove(struct pci_dev *pdev)
{
mutex_lock(&wt_lock);
if (wt_enable)
processor_thermal_mbox_interrupt_config(pdev, false,
SOC_WT_PREDICTION_INT_ENABLE_BIT,
0);
mutex_unlock(&wt_lock);
if (workload_hint_created)
sysfs_remove_group(&pdev->dev.kobj, &workload_hint_attribute_group);
workload_hint_created = false;
}
EXPORT_SYMBOL_NS_GPL(proc_thermal_wt_hint_remove, "INT340X_THERMAL");
MODULE_IMPORT_NS("INT340X_THERMAL");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Processor Thermal Work Load type hint Interface");
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