drivers/thermal/intel/intel_pch_thermal.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* intel_pch_thermal.c - Intel PCH Thermal driver
  *
  * Copyright (c) 2015, Intel Corporation.
  *
  * Authors:
  *     Tushar Dave <tushar.n.dave@intel.com>
  */

 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/pm.h>
 #include <linux/suspend.h>
 #include <linux/thermal.h>
 #include <linux/types.h>
 #include <linux/units.h>

 /* Intel PCH thermal Device IDs */
 #define PCH_THERMAL_DID_HSW_1	0x9C24 /* Haswell PCH */
 #define PCH_THERMAL_DID_HSW_2	0x8C24 /* Haswell PCH */
 #define PCH_THERMAL_DID_WPT	0x9CA4 /* Wildcat Point */
 #define PCH_THERMAL_DID_SKL	0x9D31 /* Skylake PCH */
 #define PCH_THERMAL_DID_SKL_H	0xA131 /* Skylake PCH 100 series */
 #define PCH_THERMAL_DID_CNL	0x9Df9 /* CNL PCH */
 #define PCH_THERMAL_DID_CNL_H	0xA379 /* CNL-H PCH */
 #define PCH_THERMAL_DID_CNL_LP	0x02F9 /* CNL-LP PCH */
 #define PCH_THERMAL_DID_CML_H	0X06F9 /* CML-H PCH */
 #define PCH_THERMAL_DID_LWB	0xA1B1 /* Lewisburg PCH */

 /* Wildcat Point-LP  PCH Thermal registers */
 #define WPT_TEMP	0x0000	/* Temperature */
 #define WPT_TSC	0x04	/* Thermal Sensor Control */
 #define WPT_TSS	0x06	/* Thermal Sensor Status */
 #define WPT_TSEL	0x08	/* Thermal Sensor Enable and Lock */
 #define WPT_TSREL	0x0A	/* Thermal Sensor Report Enable and Lock */
 #define WPT_TSMIC	0x0C	/* Thermal Sensor SMI Control */
 #define WPT_CTT	0x0010	/* Catastrophic Trip Point */
 #define WPT_TSPM	0x001C	/* Thermal Sensor Power Management */
 #define WPT_TAHV	0x0014	/* Thermal Alert High Value */
 #define WPT_TALV	0x0018	/* Thermal Alert Low Value */
 #define WPT_TL		0x00000040	/* Throttle Value */
 #define WPT_PHL	0x0060	/* PCH Hot Level */
 #define WPT_PHLC	0x62	/* PHL Control */
 #define WPT_TAS	0x80	/* Thermal Alert Status */
 #define WPT_TSPIEN	0x82	/* PCI Interrupt Event Enables */
 #define WPT_TSGPEN	0x84	/* General Purpose Event Enables */

 /*  Wildcat Point-LP  PCH Thermal Register bit definitions */
 #define WPT_TEMP_TSR	0x01ff	/* Temp TS Reading */
 #define WPT_TSC_CPDE	0x01	/* Catastrophic Power-Down Enable */
 #define WPT_TSS_TSDSS	0x10	/* Thermal Sensor Dynamic Shutdown Status */
 #define WPT_TSS_GPES	0x08	/* GPE status */
 #define WPT_TSEL_ETS	0x01    /* Enable TS */
 #define WPT_TSEL_PLDB	0x80	/* TSEL Policy Lock-Down Bit */
 #define WPT_TL_TOL	0x000001FF	/* T0 Level */
 #define WPT_TL_T1L	0x1ff00000	/* T1 Level */
 #define WPT_TL_TTEN	0x20000000	/* TT Enable */

 /* Resolution of 1/2 degree C and an offset of -50C */
 #define PCH_TEMP_OFFSET	(-50)
 #define GET_WPT_TEMP(x)	((x) * MILLIDEGREE_PER_DEGREE / 2 + WPT_TEMP_OFFSET)
 #define WPT_TEMP_OFFSET	(PCH_TEMP_OFFSET * MILLIDEGREE_PER_DEGREE)
 #define GET_PCH_TEMP(x)	(((x) / 2) + PCH_TEMP_OFFSET)

 /* Amount of time for each cooling delay, 100ms by default for now */
 static unsigned int delay_timeout = 100;
 module_param(delay_timeout, int, 0644);
 MODULE_PARM_DESC(delay_timeout, "amount of time delay for each iteration.");

 /* Number of iterations for cooling delay, 600 counts by default for now */
 static unsigned int delay_cnt = 600;
 module_param(delay_cnt, int, 0644);
 MODULE_PARM_DESC(delay_cnt, "total number of iterations for time delay.");

 static char driver_name[] = "Intel PCH thermal driver";

 struct pch_thermal_device {
 	void __iomem *hw_base;
 	const struct pch_dev_ops *ops;
 	struct pci_dev *pdev;
 	struct thermal_zone_device *tzd;
 	int crt_trip_id;
 	unsigned long crt_temp;
 	int hot_trip_id;
 	unsigned long hot_temp;
 	int psv_trip_id;
 	unsigned long psv_temp;
 	bool bios_enabled;
 };

 #ifdef CONFIG_ACPI

 /*
  * On some platforms, there is a companion ACPI device, which adds
  * passive trip temperature using _PSV method. There is no specific
  * passive temperature setting in MMIO interface of this PCI device.
  */
 static void pch_wpt_add_acpi_psv_trip(struct pch_thermal_device *ptd,
 				      int *nr_trips)
 {
 	struct acpi_device *adev;

 	ptd->psv_trip_id = -1;

 	adev = ACPI_COMPANION(&ptd->pdev->dev);
 	if (adev) {
 		unsigned long long r;
 		acpi_status status;

 		status = acpi_evaluate_integer(adev->handle, "_PSV", NULL,
 					       &r);
 		if (ACPI_SUCCESS(status)) {
 			unsigned long trip_temp;

 			trip_temp = deci_kelvin_to_millicelsius(r);
 			if (trip_temp) {
 				ptd->psv_temp = trip_temp;
 				ptd->psv_trip_id = *nr_trips;
 				++(*nr_trips);
 			}
 		}
 	}
 }
 #else
 static void pch_wpt_add_acpi_psv_trip(struct pch_thermal_device *ptd,
 				      int *nr_trips)
 {
 	ptd->psv_trip_id = -1;

 }
 #endif

 static int pch_wpt_init(struct pch_thermal_device *ptd, int *nr_trips)
 {
 	u8 tsel;
 	u16 trip_temp;

 	*nr_trips = 0;

 	/* Check if BIOS has already enabled thermal sensor */
 	if (WPT_TSEL_ETS & readb(ptd->hw_base + WPT_TSEL)) {
 		ptd->bios_enabled = true;
 		goto read_trips;
 	}

 	tsel = readb(ptd->hw_base + WPT_TSEL);
 	/*
 	 * When TSEL's Policy Lock-Down bit is 1, TSEL become RO.
 	 * If so, thermal sensor cannot enable. Bail out.
 	 */
 	if (tsel & WPT_TSEL_PLDB) {
 		dev_err(&ptd->pdev->dev, "Sensor can't be enabled\n");
 		return -ENODEV;
 	}

 	writeb(tsel|WPT_TSEL_ETS, ptd->hw_base + WPT_TSEL);
 	if (!(WPT_TSEL_ETS & readb(ptd->hw_base + WPT_TSEL))) {
 		dev_err(&ptd->pdev->dev, "Sensor can't be enabled\n");
 		return -ENODEV;
 	}

 read_trips:
 	ptd->crt_trip_id = -1;
 	trip_temp = readw(ptd->hw_base + WPT_CTT);
 	trip_temp &= 0x1FF;
 	if (trip_temp) {
 		ptd->crt_temp = GET_WPT_TEMP(trip_temp);
 		ptd->crt_trip_id = 0;
 		++(*nr_trips);
 	}

 	ptd->hot_trip_id = -1;
 	trip_temp = readw(ptd->hw_base + WPT_PHL);
 	trip_temp &= 0x1FF;
 	if (trip_temp) {
 		ptd->hot_temp = GET_WPT_TEMP(trip_temp);
 		ptd->hot_trip_id = *nr_trips;
 		++(*nr_trips);
 	}

 	pch_wpt_add_acpi_psv_trip(ptd, nr_trips);

 	return 0;
 }

 static int pch_wpt_get_temp(struct pch_thermal_device *ptd, int *temp)
 {
 	*temp = GET_WPT_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));

 	return 0;
 }

 /* Cool the PCH when it's overheat in .suspend_noirq phase */
 static int pch_wpt_suspend(struct pch_thermal_device *ptd)
 {
 	u8 tsel;
 	int pch_delay_cnt = 0;
 	u16 pch_thr_temp, pch_cur_temp;

 	/* Shutdown the thermal sensor if it is not enabled by BIOS */
 	if (!ptd->bios_enabled) {
 		tsel = readb(ptd->hw_base + WPT_TSEL);
 		writeb(tsel & 0xFE, ptd->hw_base + WPT_TSEL);
 		return 0;
 	}

 	/* Do not check temperature if it is not s2idle */
 	if (pm_suspend_via_firmware())
 		return 0;

 	/* Get the PCH temperature threshold value */
 	pch_thr_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TSPM));

 	/* Get the PCH current temperature value */
 	pch_cur_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));

 	/*
 	 * If current PCH temperature is higher than configured PCH threshold
 	 * value, run some delay loop with sleep to let the current temperature
 	 * go down below the threshold value which helps to allow system enter
 	 * lower power S0ix suspend state. Even after delay loop if PCH current
 	 * temperature stays above threshold, notify the warning message
 	 * which helps to indentify the reason why S0ix entry was rejected.
 	 */
 	while (pch_delay_cnt < delay_cnt) {
 		if (pch_cur_temp < pch_thr_temp)
 			break;

 		if (pm_wakeup_pending()) {
 			dev_warn(&ptd->pdev->dev, "Wakeup event detected, abort cooling\n");
 			return 0;
 		}

 		pch_delay_cnt++;
 		dev_dbg(&ptd->pdev->dev,
 			"CPU-PCH current temp [%dC] higher than the threshold temp [%dC], sleep %d times for %d ms duration\n",
 			pch_cur_temp, pch_thr_temp, pch_delay_cnt, delay_timeout);
 		msleep(delay_timeout);
 		/* Read the PCH current temperature for next cycle. */
 		pch_cur_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));
 	}

 	if (pch_cur_temp >= pch_thr_temp)
 		dev_warn(&ptd->pdev->dev,
 			"CPU-PCH is hot [%dC] after %d ms delay. S0ix might fail\n",
 			pch_cur_temp, pch_delay_cnt * delay_timeout);
 	else {
 		if (pch_delay_cnt)
 			dev_info(&ptd->pdev->dev,
 				"CPU-PCH is cool [%dC] after %d ms delay\n",
 				pch_cur_temp, pch_delay_cnt * delay_timeout);
 		else
 			dev_info(&ptd->pdev->dev,
 				"CPU-PCH is cool [%dC]\n",
 				pch_cur_temp);
 	}

 	return 0;
 }

 static int pch_wpt_resume(struct pch_thermal_device *ptd)
 {
 	u8 tsel;

 	if (ptd->bios_enabled)
 		return 0;

 	tsel = readb(ptd->hw_base + WPT_TSEL);

 	writeb(tsel | WPT_TSEL_ETS, ptd->hw_base + WPT_TSEL);

 	return 0;
 }

 struct pch_dev_ops {
 	int (*hw_init)(struct pch_thermal_device *ptd, int *nr_trips);
 	int (*get_temp)(struct pch_thermal_device *ptd, int *temp);
 	int (*suspend)(struct pch_thermal_device *ptd);
 	int (*resume)(struct pch_thermal_device *ptd);
 };


 /* dev ops for Wildcat Point */
 static const struct pch_dev_ops pch_dev_ops_wpt = {
 	.hw_init = pch_wpt_init,
 	.get_temp = pch_wpt_get_temp,
 	.suspend = pch_wpt_suspend,
 	.resume = pch_wpt_resume,
 };

 static int pch_thermal_get_temp(struct thermal_zone_device *tzd, int *temp)
 {
 	struct pch_thermal_device *ptd = tzd->devdata;

 	return	ptd->ops->get_temp(ptd, temp);
 }

 static int pch_get_trip_type(struct thermal_zone_device *tzd, int trip,
 			     enum thermal_trip_type *type)
 {
 	struct pch_thermal_device *ptd = tzd->devdata;

 	if (ptd->crt_trip_id == trip)
 		*type = THERMAL_TRIP_CRITICAL;
 	else if (ptd->hot_trip_id == trip)
 		*type = THERMAL_TRIP_HOT;
 	else if (ptd->psv_trip_id == trip)
 		*type = THERMAL_TRIP_PASSIVE;
 	else
 		return -EINVAL;

 	return 0;
 }

 static int pch_get_trip_temp(struct thermal_zone_device *tzd, int trip, int *temp)
 {
 	struct pch_thermal_device *ptd = tzd->devdata;

 	if (ptd->crt_trip_id == trip)
 		*temp = ptd->crt_temp;
 	else if (ptd->hot_trip_id == trip)
 		*temp = ptd->hot_temp;
 	else if (ptd->psv_trip_id == trip)
 		*temp = ptd->psv_temp;
 	else
 		return -EINVAL;

 	return 0;
 }

 static void pch_critical(struct thermal_zone_device *tzd)
 {
 	dev_dbg(&tzd->device, "%s: critical temperature reached\n", tzd->type);
 }

 static struct thermal_zone_device_ops tzd_ops = {
 	.get_temp = pch_thermal_get_temp,
 	.get_trip_type = pch_get_trip_type,
 	.get_trip_temp = pch_get_trip_temp,
 	.critical = pch_critical,
 };

 enum board_ids {
 	board_hsw,
 	board_wpt,
 	board_skl,
 	board_cnl,
 	board_cml,
 	board_lwb,
 };

 static const struct board_info {
 	const char *name;
 	const struct pch_dev_ops *ops;
 } board_info[] = {
 	[board_hsw] = {
 		.name = "pch_haswell",
 		.ops = &pch_dev_ops_wpt,
 	},
 	[board_wpt] = {
 		.name = "pch_wildcat_point",
 		.ops = &pch_dev_ops_wpt,
 	},
 	[board_skl] = {
 		.name = "pch_skylake",
 		.ops = &pch_dev_ops_wpt,
 	},
 	[board_cnl] = {
 		.name = "pch_cannonlake",
 		.ops = &pch_dev_ops_wpt,
 	},
 	[board_cml] = {
 		.name = "pch_cometlake",
 		.ops = &pch_dev_ops_wpt,
 	},
 	[board_lwb] = {
 		.name = "pch_lewisburg",
 		.ops = &pch_dev_ops_wpt,
 	},
 };

 static int intel_pch_thermal_probe(struct pci_dev *pdev,
 				   const struct pci_device_id *id)
 {
 	enum board_ids board_id = id->driver_data;
 	const struct board_info *bi = &board_info[board_id];
 	struct pch_thermal_device *ptd;
 	int err;
 	int nr_trips;

 	ptd = devm_kzalloc(&pdev->dev, sizeof(*ptd), GFP_KERNEL);
 	if (!ptd)
 		return -ENOMEM;

 	ptd->ops = bi->ops;

 	pci_set_drvdata(pdev, ptd);
 	ptd->pdev = pdev;

 	err = pci_enable_device(pdev);
 	if (err) {
 		dev_err(&pdev->dev, "failed to enable pci device\n");
 		return err;
 	}

 	err = pci_request_regions(pdev, driver_name);
 	if (err) {
 		dev_err(&pdev->dev, "failed to request pci region\n");
 		goto error_disable;
 	}

 	ptd->hw_base = pci_ioremap_bar(pdev, 0);
 	if (!ptd->hw_base) {
 		err = -ENOMEM;
 		dev_err(&pdev->dev, "failed to map mem base\n");
 		goto error_release;
 	}

 	err = ptd->ops->hw_init(ptd, &nr_trips);
 	if (err)
 		goto error_cleanup;

 	ptd->tzd = thermal_zone_device_register(bi->name, nr_trips, 0, ptd,
 						&tzd_ops, NULL, 0, 0);
 	if (IS_ERR(ptd->tzd)) {
 		dev_err(&pdev->dev, "Failed to register thermal zone %s\n",
 			bi->name);
 		err = PTR_ERR(ptd->tzd);
 		goto error_cleanup;
 	}
 	err = thermal_zone_device_enable(ptd->tzd);
 	if (err)
 		goto err_unregister;

 	return 0;

 err_unregister:
 	thermal_zone_device_unregister(ptd->tzd);
 error_cleanup:
 	iounmap(ptd->hw_base);
 error_release:
 	pci_release_regions(pdev);
 error_disable:
 	pci_disable_device(pdev);
 	dev_err(&pdev->dev, "pci device failed to probe\n");
 	return err;
 }

 static void intel_pch_thermal_remove(struct pci_dev *pdev)
 {
 	struct pch_thermal_device *ptd = pci_get_drvdata(pdev);

 	thermal_zone_device_unregister(ptd->tzd);
 	iounmap(ptd->hw_base);
 	pci_set_drvdata(pdev, NULL);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 }

 static int intel_pch_thermal_suspend_noirq(struct device *device)
 {
 	struct pch_thermal_device *ptd = dev_get_drvdata(device);

 	return ptd->ops->suspend(ptd);
 }

 static int intel_pch_thermal_resume(struct device *device)
 {
 	struct pch_thermal_device *ptd = dev_get_drvdata(device);

 	return ptd->ops->resume(ptd);
 }

 static const struct pci_device_id intel_pch_thermal_id[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_HSW_1),
 		.driver_data = board_hsw, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_HSW_2),
 		.driver_data = board_hsw, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_WPT),
 		.driver_data = board_wpt, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_SKL),
 		.driver_data = board_skl, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_SKL_H),
 		.driver_data = board_skl, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL),
 		.driver_data = board_cnl, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL_H),
 		.driver_data = board_cnl, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL_LP),
 		.driver_data = board_cnl, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CML_H),
 		.driver_data = board_cml, },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_LWB),
 		.driver_data = board_lwb, },
 	{ 0, },
 };
 MODULE_DEVICE_TABLE(pci, intel_pch_thermal_id);

 static const struct dev_pm_ops intel_pch_pm_ops = {
 	.suspend_noirq = intel_pch_thermal_suspend_noirq,
 	.resume = intel_pch_thermal_resume,
 };

 static struct pci_driver intel_pch_thermal_driver = {
 	.name		= "intel_pch_thermal",
 	.id_table	= intel_pch_thermal_id,
 	.probe		= intel_pch_thermal_probe,
 	.remove		= intel_pch_thermal_remove,
 	.driver.pm	= &intel_pch_pm_ops,
 };

 module_pci_driver(intel_pch_thermal_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Intel PCH Thermal driver");
	// SPDX-License-Identifier: GPL-2.0-only
	/* intel_pch_thermal.c - Intel PCH Thermal driver
	*
	* Copyright (c) 2015, Intel Corporation.
	*
	* Authors:
	* Tushar Dave <tushar.n.dave@intel.com>
	*/

	#include <linux/acpi.h>
	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/pci.h>
	#include <linux/pm.h>
	#include <linux/suspend.h>
	#include <linux/thermal.h>
	#include <linux/types.h>
	#include <linux/units.h>

	/* Intel PCH thermal Device IDs */
	#define PCH_THERMAL_DID_HSW_1 0x9C24 /* Haswell PCH */
	#define PCH_THERMAL_DID_HSW_2 0x8C24 /* Haswell PCH */
	#define PCH_THERMAL_DID_WPT 0x9CA4 /* Wildcat Point */
	#define PCH_THERMAL_DID_SKL 0x9D31 /* Skylake PCH */
	#define PCH_THERMAL_DID_SKL_H 0xA131 /* Skylake PCH 100 series */
	#define PCH_THERMAL_DID_CNL 0x9Df9 /* CNL PCH */
	#define PCH_THERMAL_DID_CNL_H 0xA379 /* CNL-H PCH */
	#define PCH_THERMAL_DID_CNL_LP 0x02F9 /* CNL-LP PCH */
	#define PCH_THERMAL_DID_CML_H 0X06F9 /* CML-H PCH */
	#define PCH_THERMAL_DID_LWB 0xA1B1 /* Lewisburg PCH */

	/* Wildcat Point-LP PCH Thermal registers */
	#define WPT_TEMP 0x0000 /* Temperature */
	#define WPT_TSC 0x04 /* Thermal Sensor Control */
	#define WPT_TSS 0x06 /* Thermal Sensor Status */
	#define WPT_TSEL 0x08 /* Thermal Sensor Enable and Lock */
	#define WPT_TSREL 0x0A /* Thermal Sensor Report Enable and Lock */
	#define WPT_TSMIC 0x0C /* Thermal Sensor SMI Control */
	#define WPT_CTT 0x0010 /* Catastrophic Trip Point */
	#define WPT_TSPM 0x001C /* Thermal Sensor Power Management */
	#define WPT_TAHV 0x0014 /* Thermal Alert High Value */
	#define WPT_TALV 0x0018 /* Thermal Alert Low Value */
	#define WPT_TL 0x00000040 /* Throttle Value */
	#define WPT_PHL 0x0060 /* PCH Hot Level */
	#define WPT_PHLC 0x62 /* PHL Control */
	#define WPT_TAS 0x80 /* Thermal Alert Status */
	#define WPT_TSPIEN 0x82 /* PCI Interrupt Event Enables */
	#define WPT_TSGPEN 0x84 /* General Purpose Event Enables */

	/* Wildcat Point-LP PCH Thermal Register bit definitions */
	#define WPT_TEMP_TSR 0x01ff /* Temp TS Reading */
	#define WPT_TSC_CPDE 0x01 /* Catastrophic Power-Down Enable */
	#define WPT_TSS_TSDSS 0x10 /* Thermal Sensor Dynamic Shutdown Status */
	#define WPT_TSS_GPES 0x08 /* GPE status */
	#define WPT_TSEL_ETS 0x01 /* Enable TS */
	#define WPT_TSEL_PLDB 0x80 /* TSEL Policy Lock-Down Bit */
	#define WPT_TL_TOL 0x000001FF /* T0 Level */
	#define WPT_TL_T1L 0x1ff00000 /* T1 Level */
	#define WPT_TL_TTEN 0x20000000 /* TT Enable */

	/* Resolution of 1/2 degree C and an offset of -50C */
	#define PCH_TEMP_OFFSET (-50)
	#define GET_WPT_TEMP(x) ((x) * MILLIDEGREE_PER_DEGREE / 2 + WPT_TEMP_OFFSET)
	#define WPT_TEMP_OFFSET (PCH_TEMP_OFFSET * MILLIDEGREE_PER_DEGREE)
	#define GET_PCH_TEMP(x) (((x) / 2) + PCH_TEMP_OFFSET)

	/* Amount of time for each cooling delay, 100ms by default for now */
	static unsigned int delay_timeout = 100;
	module_param(delay_timeout, int, 0644);
	MODULE_PARM_DESC(delay_timeout, "amount of time delay for each iteration.");

	/* Number of iterations for cooling delay, 600 counts by default for now */
	static unsigned int delay_cnt = 600;
	module_param(delay_cnt, int, 0644);
	MODULE_PARM_DESC(delay_cnt, "total number of iterations for time delay.");

	static char driver_name[] = "Intel PCH thermal driver";

	struct pch_thermal_device {
	void __iomem *hw_base;
	const struct pch_dev_ops *ops;
	struct pci_dev *pdev;
	struct thermal_zone_device *tzd;
	int crt_trip_id;
	unsigned long crt_temp;
	int hot_trip_id;
	unsigned long hot_temp;
	int psv_trip_id;
	unsigned long psv_temp;
	bool bios_enabled;
	};

	#ifdef CONFIG_ACPI

	/*
	* On some platforms, there is a companion ACPI device, which adds
	* passive trip temperature using _PSV method. There is no specific
	* passive temperature setting in MMIO interface of this PCI device.
	*/
	static void pch_wpt_add_acpi_psv_trip(struct pch_thermal_device *ptd,
	int *nr_trips)
	{
	struct acpi_device *adev;

	ptd->psv_trip_id = -1;

	adev = ACPI_COMPANION(&ptd->pdev->dev);
	if (adev) {
	unsigned long long r;
	acpi_status status;

	status = acpi_evaluate_integer(adev->handle, "_PSV", NULL,
	&r);
	if (ACPI_SUCCESS(status)) {
	unsigned long trip_temp;

	trip_temp = deci_kelvin_to_millicelsius(r);
	if (trip_temp) {
	ptd->psv_temp = trip_temp;
	ptd->psv_trip_id = *nr_trips;
	++(*nr_trips);
	}
	}
	}
	}
	#else
	static void pch_wpt_add_acpi_psv_trip(struct pch_thermal_device *ptd,
	int *nr_trips)
	{
	ptd->psv_trip_id = -1;

	}
	#endif

	static int pch_wpt_init(struct pch_thermal_device ptd, int nr_trips)
	{
	u8 tsel;
	u16 trip_temp;

	*nr_trips = 0;

	/* Check if BIOS has already enabled thermal sensor */
	if (WPT_TSEL_ETS & readb(ptd->hw_base + WPT_TSEL)) {
	ptd->bios_enabled = true;
	goto read_trips;
	}

	tsel = readb(ptd->hw_base + WPT_TSEL);
	/*
	* When TSEL's Policy Lock-Down bit is 1, TSEL become RO.
	* If so, thermal sensor cannot enable. Bail out.
	*/
	if (tsel & WPT_TSEL_PLDB) {
	dev_err(&ptd->pdev->dev, "Sensor can't be enabled\n");
	return -ENODEV;
	}

	writeb(tsel\|WPT_TSEL_ETS, ptd->hw_base + WPT_TSEL);
	if (!(WPT_TSEL_ETS & readb(ptd->hw_base + WPT_TSEL))) {
	dev_err(&ptd->pdev->dev, "Sensor can't be enabled\n");
	return -ENODEV;
	}

	read_trips:
	ptd->crt_trip_id = -1;
	trip_temp = readw(ptd->hw_base + WPT_CTT);
	trip_temp &= 0x1FF;
	if (trip_temp) {
	ptd->crt_temp = GET_WPT_TEMP(trip_temp);
	ptd->crt_trip_id = 0;
	++(*nr_trips);
	}

	ptd->hot_trip_id = -1;
	trip_temp = readw(ptd->hw_base + WPT_PHL);
	trip_temp &= 0x1FF;
	if (trip_temp) {
	ptd->hot_temp = GET_WPT_TEMP(trip_temp);
	ptd->hot_trip_id = *nr_trips;
	++(*nr_trips);
	}

	pch_wpt_add_acpi_psv_trip(ptd, nr_trips);

	return 0;
	}

	static int pch_wpt_get_temp(struct pch_thermal_device ptd, int temp)
	{
	*temp = GET_WPT_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));

	return 0;
	}

	/* Cool the PCH when it's overheat in .suspend_noirq phase */
	static int pch_wpt_suspend(struct pch_thermal_device *ptd)
	{
	u8 tsel;
	int pch_delay_cnt = 0;
	u16 pch_thr_temp, pch_cur_temp;

	/* Shutdown the thermal sensor if it is not enabled by BIOS */
	if (!ptd->bios_enabled) {
	tsel = readb(ptd->hw_base + WPT_TSEL);
	writeb(tsel & 0xFE, ptd->hw_base + WPT_TSEL);
	return 0;
	}

	/* Do not check temperature if it is not s2idle */
	if (pm_suspend_via_firmware())
	return 0;

	/* Get the PCH temperature threshold value */
	pch_thr_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TSPM));

	/* Get the PCH current temperature value */
	pch_cur_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));

	/*
	* If current PCH temperature is higher than configured PCH threshold
	* value, run some delay loop with sleep to let the current temperature
	* go down below the threshold value which helps to allow system enter
	* lower power S0ix suspend state. Even after delay loop if PCH current
	* temperature stays above threshold, notify the warning message
	* which helps to indentify the reason why S0ix entry was rejected.
	*/
	while (pch_delay_cnt < delay_cnt) {
	if (pch_cur_temp < pch_thr_temp)
	break;

	if (pm_wakeup_pending()) {
	dev_warn(&ptd->pdev->dev, "Wakeup event detected, abort cooling\n");
	return 0;
	}

	pch_delay_cnt++;
	dev_dbg(&ptd->pdev->dev,
	"CPU-PCH current temp [%dC] higher than the threshold temp [%dC], sleep %d times for %d ms duration\n",
	pch_cur_temp, pch_thr_temp, pch_delay_cnt, delay_timeout);
	msleep(delay_timeout);
	/* Read the PCH current temperature for next cycle. */
	pch_cur_temp = GET_PCH_TEMP(WPT_TEMP_TSR & readw(ptd->hw_base + WPT_TEMP));
	}

	if (pch_cur_temp >= pch_thr_temp)
	dev_warn(&ptd->pdev->dev,
	"CPU-PCH is hot [%dC] after %d ms delay. S0ix might fail\n",
	pch_cur_temp, pch_delay_cnt * delay_timeout);
	else {
	if (pch_delay_cnt)
	dev_info(&ptd->pdev->dev,
	"CPU-PCH is cool [%dC] after %d ms delay\n",
	pch_cur_temp, pch_delay_cnt * delay_timeout);
	else
	dev_info(&ptd->pdev->dev,
	"CPU-PCH is cool [%dC]\n",
	pch_cur_temp);
	}

	return 0;
	}

	static int pch_wpt_resume(struct pch_thermal_device *ptd)
	{
	u8 tsel;

	if (ptd->bios_enabled)
	return 0;

	tsel = readb(ptd->hw_base + WPT_TSEL);

	writeb(tsel \| WPT_TSEL_ETS, ptd->hw_base + WPT_TSEL);

	return 0;
	}

	struct pch_dev_ops {
	int (hw_init)(struct pch_thermal_device ptd, int *nr_trips);
	int (get_temp)(struct pch_thermal_device ptd, int *temp);
	int (suspend)(struct pch_thermal_device ptd);
	int (resume)(struct pch_thermal_device ptd);
	};


	/* dev ops for Wildcat Point */
	static const struct pch_dev_ops pch_dev_ops_wpt = {
	.hw_init = pch_wpt_init,
	.get_temp = pch_wpt_get_temp,
	.suspend = pch_wpt_suspend,
	.resume = pch_wpt_resume,
	};

	static int pch_thermal_get_temp(struct thermal_zone_device tzd, int temp)
	{
	struct pch_thermal_device *ptd = tzd->devdata;

	return ptd->ops->get_temp(ptd, temp);
	}

	static int pch_get_trip_type(struct thermal_zone_device *tzd, int trip,
	enum thermal_trip_type *type)
	{
	struct pch_thermal_device *ptd = tzd->devdata;

	if (ptd->crt_trip_id == trip)
	*type = THERMAL_TRIP_CRITICAL;
	else if (ptd->hot_trip_id == trip)
	*type = THERMAL_TRIP_HOT;
	else if (ptd->psv_trip_id == trip)
	*type = THERMAL_TRIP_PASSIVE;
	else
	return -EINVAL;

	return 0;
	}

	static int pch_get_trip_temp(struct thermal_zone_device tzd, int trip, int temp)
	{
	struct pch_thermal_device *ptd = tzd->devdata;

	if (ptd->crt_trip_id == trip)
	*temp = ptd->crt_temp;
	else if (ptd->hot_trip_id == trip)
	*temp = ptd->hot_temp;
	else if (ptd->psv_trip_id == trip)
	*temp = ptd->psv_temp;
	else
	return -EINVAL;

	return 0;
	}

	static void pch_critical(struct thermal_zone_device *tzd)
	{
	dev_dbg(&tzd->device, "%s: critical temperature reached\n", tzd->type);
	}

	static struct thermal_zone_device_ops tzd_ops = {
	.get_temp = pch_thermal_get_temp,
	.get_trip_type = pch_get_trip_type,
	.get_trip_temp = pch_get_trip_temp,
	.critical = pch_critical,
	};

	enum board_ids {
	board_hsw,
	board_wpt,
	board_skl,
	board_cnl,
	board_cml,
	board_lwb,
	};

	static const struct board_info {
	const char *name;
	const struct pch_dev_ops *ops;
	} board_info[] = {
	[board_hsw] = {
	.name = "pch_haswell",
	.ops = &pch_dev_ops_wpt,
	},
	[board_wpt] = {
	.name = "pch_wildcat_point",
	.ops = &pch_dev_ops_wpt,
	},
	[board_skl] = {
	.name = "pch_skylake",
	.ops = &pch_dev_ops_wpt,
	},
	[board_cnl] = {
	.name = "pch_cannonlake",
	.ops = &pch_dev_ops_wpt,
	},
	[board_cml] = {
	.name = "pch_cometlake",
	.ops = &pch_dev_ops_wpt,
	},
	[board_lwb] = {
	.name = "pch_lewisburg",
	.ops = &pch_dev_ops_wpt,
	},
	};

	static int intel_pch_thermal_probe(struct pci_dev *pdev,
	const struct pci_device_id *id)
	{
	enum board_ids board_id = id->driver_data;
	const struct board_info *bi = &board_info[board_id];
	struct pch_thermal_device *ptd;
	int err;
	int nr_trips;

	ptd = devm_kzalloc(&pdev->dev, sizeof(*ptd), GFP_KERNEL);
	if (!ptd)
	return -ENOMEM;

	ptd->ops = bi->ops;

	pci_set_drvdata(pdev, ptd);
	ptd->pdev = pdev;

	err = pci_enable_device(pdev);
	if (err) {
	dev_err(&pdev->dev, "failed to enable pci device\n");
	return err;
	}

	err = pci_request_regions(pdev, driver_name);
	if (err) {
	dev_err(&pdev->dev, "failed to request pci region\n");
	goto error_disable;
	}

	ptd->hw_base = pci_ioremap_bar(pdev, 0);
	if (!ptd->hw_base) {
	err = -ENOMEM;
	dev_err(&pdev->dev, "failed to map mem base\n");
	goto error_release;
	}

	err = ptd->ops->hw_init(ptd, &nr_trips);
	if (err)
	goto error_cleanup;

	ptd->tzd = thermal_zone_device_register(bi->name, nr_trips, 0, ptd,
	&tzd_ops, NULL, 0, 0);
	if (IS_ERR(ptd->tzd)) {
	dev_err(&pdev->dev, "Failed to register thermal zone %s\n",
	bi->name);
	err = PTR_ERR(ptd->tzd);
	goto error_cleanup;
	}
	err = thermal_zone_device_enable(ptd->tzd);
	if (err)
	goto err_unregister;

	return 0;

	err_unregister:
	thermal_zone_device_unregister(ptd->tzd);
	error_cleanup:
	iounmap(ptd->hw_base);
	error_release:
	pci_release_regions(pdev);
	error_disable:
	pci_disable_device(pdev);
	dev_err(&pdev->dev, "pci device failed to probe\n");
	return err;
	}

	static void intel_pch_thermal_remove(struct pci_dev *pdev)
	{
	struct pch_thermal_device *ptd = pci_get_drvdata(pdev);

	thermal_zone_device_unregister(ptd->tzd);
	iounmap(ptd->hw_base);
	pci_set_drvdata(pdev, NULL);
	pci_release_regions(pdev);
	pci_disable_device(pdev);
	}

	static int intel_pch_thermal_suspend_noirq(struct device *device)
	{
	struct pch_thermal_device *ptd = dev_get_drvdata(device);

	return ptd->ops->suspend(ptd);
	}

	static int intel_pch_thermal_resume(struct device *device)
	{
	struct pch_thermal_device *ptd = dev_get_drvdata(device);

	return ptd->ops->resume(ptd);
	}

	static const struct pci_device_id intel_pch_thermal_id[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_HSW_1),
	.driver_data = board_hsw, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_HSW_2),
	.driver_data = board_hsw, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_WPT),
	.driver_data = board_wpt, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_SKL),
	.driver_data = board_skl, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_SKL_H),
	.driver_data = board_skl, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL),
	.driver_data = board_cnl, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL_H),
	.driver_data = board_cnl, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CNL_LP),
	.driver_data = board_cnl, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_CML_H),
	.driver_data = board_cml, },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCH_THERMAL_DID_LWB),
	.driver_data = board_lwb, },
	{ 0, },
	};
	MODULE_DEVICE_TABLE(pci, intel_pch_thermal_id);

	static const struct dev_pm_ops intel_pch_pm_ops = {
	.suspend_noirq = intel_pch_thermal_suspend_noirq,
	.resume = intel_pch_thermal_resume,
	};

	static struct pci_driver intel_pch_thermal_driver = {
	.name = "intel_pch_thermal",
	.id_table = intel_pch_thermal_id,
	.probe = intel_pch_thermal_probe,
	.remove = intel_pch_thermal_remove,
	.driver.pm = &intel_pch_pm_ops,
	};

	module_pci_driver(intel_pch_thermal_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("Intel PCH Thermal driver");