1 files changed, 255 insertions, 0 deletions
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_wt_hint.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_wt_hint.c
new file mode 100644
index 000000000000..9d5e4c169d1b
--- /dev/null
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_wt_hint.c
@@ -0,0 +1,255 @@
+// 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");