----------------------------------------
Refer to Documentation/admin-guide/acpi/fan_performance_states.rst
+
+Workload Type Hints
+----------------------------------------
+
+The firmware in Meteor Lake processor generation is capable of identifying
+workload type and passing hints regarding it to the OS. A special sysfs
+interface is provided to allow user space to obtain workload type hints from
+the firmware and control the rate at which they are provided.
+
+User space can poll attribute "workload_type_index" for the current hint or
+can receive a notification whenever the value of this attribute is updated.
+
+file:`/sys/bus/pci/devices/0000:00:04.0/workload_hint/`
+Segment 0, bus 0, device 4, function 0 is reserved for the processor thermal
+device on all Intel client processors. So, the above path doesn't change
+based on the processor generation.
+
+``workload_hint_enable`` (RW)
+ Enable firmware to send workload type hints to user space.
+
+``notification_delay_ms`` (RW)
+ Minimum delay in milliseconds before firmware will notify OS. This is
+ for the rate control of notifications. This delay is between changing
+ the workload type prediction in the firmware and notifying the OS about
+ the change. The default delay is 1024 ms. The delay of 0 is invalid.
+ The delay is rounded up to the nearest power of 2 to simplify firmware
+ programming of the delay value. The read of notification_delay_ms
+ attribute shows the effective value used.
+
+``workload_type_index`` (RO)
+ Predicted workload type index. User space can get notification of
+ change via existing sysfs attribute change notification mechanism.
+
+ The supported index values and their meaning for the Meteor Lake
+ processor generation are as follows:
+
+ 0 - Idle: System performs no tasks, power and idle residency are
+ consistently low for long periods of time.
+
+ 1 – Battery Life: Power is relatively low, but the processor may
+ still be actively performing a task, such as video playback for
+ a long period of time.
+
+ 2 – Sustained: Power level that is relatively high for a long period
+ of time, with very few to no periods of idleness, which will
+ eventually exhaust RAPL Power Limit 1 and 2.
+
+ 3 – Bursty: Consumes a relatively constant average amount of power, but
+ periods of relative idleness are interrupted by bursts of
+ activity. The bursts are relatively short and the periods of
+ relative idleness between them typically prevent RAPL Power
+ Limit 1 from being exhausted.
+
+ 4 – Unknown: Can't classify.
--- /dev/null
+// 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_RES_INT_STATUS_OFFSET 0x5B18
+#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;
+
+ writeq(status & ~SOC_WT_PREDICTION_INT_ACTIVE,
+ proc_priv->mmio_base + SOC_WT_RES_INT_STATUS_OFFSET);
+ 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");
projects / users / hch / block.git / commitdiff