[V3] thermal: intel: introduce tcc cooling driver

diff --git a/drivers/thermal/intel/Kconfig b/drivers/thermal/intel/Kconfig
index ce4f59213c7a..e4299ca3423c 100644
--- a/drivers/thermal/intel/Kconfig
+++ b/drivers/thermal/intel/Kconfig
@@ -79,3 +79,14 @@  config INTEL_PCH_THERMAL
 	  Enable this to support thermal reporting on certain intel PCHs.
 	  Thermal reporting device will provide temperature reading,
 	  programmable trip points and other information.
+
+config INTEL_TCC_COOLING
+	tristate "Intel TCC offset cooling Driver"
+	depends on X86
+	help
+	  Enable this to support system cooling by adjusting the effective TCC
+	  activation temperature via the TCC Offset register, which is widely
+	  supported on modern Intel platforms.
+	  Note that, on different platforms, the behavior might be different
+	  on how fast the setting takes effect, and how much the CPU frequency
+	  is reduced.
diff --git a/drivers/thermal/intel/Makefile b/drivers/thermal/intel/Makefile
index ff2ad30ef397..5ff2afa388f7 100644
--- a/drivers/thermal/intel/Makefile
+++ b/drivers/thermal/intel/Makefile
@@ -10,4 +10,5 @@  obj-$(CONFIG_INTEL_QUARK_DTS_THERMAL)	+= intel_quark_dts_thermal.o
 obj-$(CONFIG_INT340X_THERMAL)  += int340x_thermal/
 obj-$(CONFIG_INTEL_BXT_PMIC_THERMAL) += intel_bxt_pmic_thermal.o
 obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
+obj-$(CONFIG_INTEL_TCC_COOLING)	+= intel_tcc_cooling.o
 obj-$(CONFIG_X86_THERMAL_VECTOR) += therm_throt.o
diff --git a/drivers/thermal/intel/intel_tcc_cooling.c b/drivers/thermal/intel/intel_tcc_cooling.c
new file mode 100644
index 000000000000..8ec10d55d421
--- /dev/null
+++ b/drivers/thermal/intel/intel_tcc_cooling.c
@@ -0,0 +1,129 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * cooling device driver that activates the processor throttling by
+ * programming the TCC Offset register.
+ * Copyright (c) 2021, Intel Corporation.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/thermal.h>
+#include <asm/cpu_device_id.h>
+
+#define TCC_SHIFT 24
+#define TCC_MASK	(0x3fULL<<24)
+#define TCC_PROGRAMMABLE	BIT(30)
+
+static struct thermal_cooling_device *tcc_cdev;
+
+static int tcc_get_max_state(struct thermal_cooling_device *cdev, unsigned long
+			     *state)
+{
+	*state = TCC_MASK >> TCC_SHIFT;
+	return 0;
+}
+
+static int tcc_offset_update(int tcc)
+{
+	u64 val;
+	int err;
+
+	err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
+	if (err)
+		return err;
+
+	val &= ~TCC_MASK;
+	val |= tcc << TCC_SHIFT;
+
+	err = wrmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, val);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int tcc_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
+			     *state)
+{
+	u64 val;
+	int err;
+
+	err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
+	if (err)
+		return err;
+
+	*state = (val & TCC_MASK) >> TCC_SHIFT;
+	return 0;
+}
+
+static int tcc_set_cur_state(struct thermal_cooling_device *cdev, unsigned long
+			     state)
+{
+	return tcc_offset_update(state);
+}
+
+static const struct thermal_cooling_device_ops tcc_cooling_ops = {
+	.get_max_state = tcc_get_max_state,
+	.get_cur_state = tcc_get_cur_state,
+	.set_cur_state = tcc_set_cur_state,
+};
+
+static const struct x86_cpu_id tcc_ids[] __initconst = {
+	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L, NULL),
+	X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE, NULL),
+	{}
+};
+
+MODULE_DEVICE_TABLE(x86cpu, tcc_ids);
+
+static int __init tcc_cooling_init(void)
+{
+	int ret;
+	u64 val;
+	const struct x86_cpu_id *id;
+
+	int err;
+
+	id = x86_match_cpu(tcc_ids);
+	if (!id)
+		return -ENODEV;
+
+	err = rdmsrl_safe(MSR_PLATFORM_INFO, &val);
+	if (err)
+		return err;
+
+	if (!(val & TCC_PROGRAMMABLE))
+		return -ENODEV;
+
+	pr_info("Programmable TCC Offset detected\n");
+
+	tcc_cdev =
+	    thermal_cooling_device_register("TCC Offset", NULL,
+					    &tcc_cooling_ops);
+	if (IS_ERR(tcc_cdev)) {
+		ret = PTR_ERR(tcc_cdev);
+		return ret;
+	}
+	return 0;
+}
+
+module_init(tcc_cooling_init)
+
+static void __exit tcc_cooling_exit(void)
+{
+	thermal_cooling_device_unregister(tcc_cdev);
+}
+
+module_exit(tcc_cooling_exit)
+
+MODULE_DESCRIPTION("TCC offset cooling device Driver");
+MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
+MODULE_LICENSE("GPL v2");