[v3,5/7] thermal: int340x: processor_thermal: Add workload type hint interface

diff --git a/Documentation/driver-api/thermal/intel_dptf.rst b/Documentation/driver-api/thermal/intel_dptf.rst
index 9ab4316322a1..9a2b31320f10 100644
--- a/Documentation/driver-api/thermal/intel_dptf.rst
+++ b/Documentation/driver-api/thermal/intel_dptf.rst
@@ -315,3 +315,54 @@  DPTF Fan Control
 ----------------------------------------
 
 Refer to Documentation/admin-guide/acpi/fan_performance_states.rst
+
+Workload Type Hints
+----------------------------------------
+
+The firmware in Meteor Lake processor generation is capable of predicting
+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/`
+The 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.
diff --git a/drivers/thermal/intel/int340x_thermal/Makefile b/drivers/thermal/intel/int340x_thermal/Makefile
index 7e40aebb0556..f33a3ad3bef3 100644
--- a/drivers/thermal/intel/int340x_thermal/Makefile
+++ b/drivers/thermal/intel/int340x_thermal/Makefile
@@ -11,5 +11,6 @@  obj-$(CONFIG_PROC_THERMAL_MMIO_RAPL) += processor_thermal_rapl.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_rfim.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_mbox.o
 obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_req.o
+obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_wt_hint.o
 obj-$(CONFIG_INT3406_THERMAL)	+= int3406_thermal.o
 obj-$(CONFIG_ACPI_THERMAL_REL)	+= acpi_thermal_rel.o
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
index 3f0eac6cb4da..29ed7d0f7022 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
@@ -352,6 +352,12 @@  int proc_thermal_mmio_add(struct pci_dev *pdev,
 			dev_err(&pdev->dev, "failed to add MBOX interface\n");
 			goto err_rem_rfim;
 		}
+	} else if (feature_mask & PROC_THERMAL_FEATURE_WT_HINT) {
+		ret = proc_thermal_wt_hint_add(pdev, proc_priv);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to add WT Hint\n");
+			goto err_rem_rfim;
+		}
 	}
 
 	return 0;
@@ -376,10 +382,13 @@  void proc_thermal_mmio_remove(struct pci_dev *pdev, struct proc_thermal_device *
 
 	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_WT_REQ)
 		proc_thermal_wt_req_remove(pdev);
+	else if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_WT_HINT)
+		proc_thermal_wt_hint_remove(pdev);
 }
 EXPORT_SYMBOL_GPL(proc_thermal_mmio_remove);
 
 MODULE_IMPORT_NS(INTEL_TCC);
+MODULE_IMPORT_NS(INT340X_THERMAL);
 MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
 MODULE_DESCRIPTION("Processor Thermal Reporting Device Driver");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
index 0e7725829c24..b974583c5c11 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
@@ -61,6 +61,7 @@  struct rapl_mmio_regs {
 #define PROC_THERMAL_FEATURE_DVFS	0x04
 #define PROC_THERMAL_FEATURE_WT_REQ	0x08
 #define PROC_THERMAL_FEATURE_DLVR	0x10
+#define PROC_THERMAL_FEATURE_WT_HINT	0x20
 
 #if IS_ENABLED(CONFIG_PROC_THERMAL_MMIO_RAPL)
 int proc_thermal_rapl_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
@@ -95,6 +96,12 @@  int processor_thermal_mbox_interrupt_config(struct pci_dev *pdev, bool enable, i
 					    int time_window);
 int proc_thermal_add(struct device *dev, struct proc_thermal_device *priv);
 void proc_thermal_remove(struct proc_thermal_device *proc_priv);
+
+int proc_thermal_wt_hint_add(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
+void proc_thermal_wt_hint_remove(struct pci_dev *pdev);
+void proc_thermal_wt_intr_callback(struct pci_dev *pdev, struct proc_thermal_device *proc_priv);
+bool proc_thermal_check_wt_intr(struct proc_thermal_device *proc_priv);
+
 int proc_thermal_suspend(struct device *dev);
 int proc_thermal_resume(struct device *dev);
 int proc_thermal_mmio_add(struct pci_dev *pdev,
diff --git a/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c b/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
index db30c11fd1f7..eed59630fe59 100644
--- a/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_device_pci.c
@@ -365,7 +365,8 @@  static const struct pci_device_id proc_thermal_pci_ids[] = {
 	{ PCI_DEVICE_DATA(INTEL, ADL_THERMAL, PROC_THERMAL_FEATURE_RAPL |
 	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_WT_REQ) },
 	{ PCI_DEVICE_DATA(INTEL, MTLP_THERMAL, PROC_THERMAL_FEATURE_RAPL |
-	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_DLVR) },
+	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_DLVR |
+	  PROC_THERMAL_FEATURE_WT_HINT) },
 	{ PCI_DEVICE_DATA(INTEL, RPL_THERMAL, PROC_THERMAL_FEATURE_RAPL |
 	  PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS | PROC_THERMAL_FEATURE_WT_REQ) },
 	{ },
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..389fed944c42
--- /dev/null
+++ b/drivers/thermal/intel/int340x_thermal/processor_thermal_wt_hint.c
@@ -0,0 +1,253 @@ 
+// 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:
+ *	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 the interrupt context.
+ * - proc_thermal_wt_intr_callback(): Callback for interrupt processing
+ * under 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");