[PATCHv3 1/1] thermal: intel Quark SoC X1000 DTS thermal driver

[Ong Boon Leong]

In Intel Quark SoC X1000, there is one on-die digital temperature sensor(DTS).
The DTS offers both hot & critical trip points.

However, in current distribution of UEFI BIOS for Quark platform, only
critical trip point is configured to be 105 degree Celsius (based on Quark
SW ver1.0.1 and hot trip point is not used due to lack of IRQ.

There is no active cooling device for Quark SoC, so Quark SoC thermal
management logic expects Linux distro to orderly power-off when temperature
of the DTS exceeds the configured critical trip point.

Kernel param "polling_delay" in milliseconds is used to control the frequency
the DTS temperature is read by thermal framework. It defaults to 2-second.
To change it, use kernel boot param "intel_quark_dts_thermal.polling_delay=X".

User interacts with Quark SoC DTS thermal driver through sysfs via:
/sys/class/thermal/thermal_zone0/

For example:
 - to read DTS temperature
   $ cat temp
 - to read critical trip point
   $ cat trip_point_0_temp
 - to read trip point type
   $ cat trip_point_0_type
 - to emulate temperature raise to test orderly shutdown by Linux distro
   $ echo 105 > emul_temp

Tested-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
Signed-off-by: Ong Boon Leong <boon.leong.ong@xxxxxxxxx>
Reviewed-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
---
 drivers/thermal/Kconfig                   |   10 +
 drivers/thermal/Makefile                  |    1 +
 drivers/thermal/intel_quark_dts_thermal.c |  434 +++++++++++++++++++++++++++++
 3 files changed, 445 insertions(+)
 create mode 100644 drivers/thermal/intel_quark_dts_thermal.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index f554d25..f192b2b 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -229,6 +229,16 @@ config INTEL_SOC_DTS_THERMAL
 	  notification methods.The other trip is a critical trip point, which
 	  was set by the driver based on the TJ MAX temperature.
 
+config INTEL_QUARK_DTS_THERMAL
+	tristate "Intel Quark DTS thermal driver"
+	depends on X86_INTEL_QUARK
+	help
+	  Enable this to register Intel Quark SoC (e.g. X1000) platform digital
+	  temperature sensor (DTS). For X1000 SoC, it has one on-die DTS.
+	  The DTS will be registered as a thermal zone. There are two trip points:
+	  hot & critical. The critical trip point default value is set by
+	  underlying BIOS/Firmware.
+
 config INT340X_THERMAL
 	tristate "ACPI INT340X thermal drivers"
 	depends on X86 && ACPI
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 39c4fe8..50c5991 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
 obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
 obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
 obj-$(CONFIG_INTEL_SOC_DTS_THERMAL)	+= intel_soc_dts_thermal.o
+obj-$(CONFIG_INTEL_QUARK_DTS_THERMAL)	+= intel_quark_dts_thermal.o
 obj-$(CONFIG_TI_SOC_THERMAL)	+= ti-soc-thermal/
 obj-$(CONFIG_INT340X_THERMAL)  += int340x_thermal/
 obj-$(CONFIG_ST_THERMAL)	+= st/
diff --git a/drivers/thermal/intel_quark_dts_thermal.c b/drivers/thermal/intel_quark_dts_thermal.c
new file mode 100644
index 0000000..ca605ed
--- /dev/null
+++ b/drivers/thermal/intel_quark_dts_thermal.c
@@ -0,0 +1,434 @@
+/*
+ * intel_quark_dts_thermal.c
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * Quark DTS thermal driver is implemented by referencing
+ * intel_soc_dts_thermal.c.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/thermal.h>
+#include <asm/cpu_device_id.h>
+#include <asm/iosf_mbi.h>
+
+#define X86_FAMILY_QUARK	0x5
+#define X86_MODEL_QUARK_X1000	0x9
+
+/* DTS reset is programmed via QRK_MBI_UNIT_SOC */
+#define QRK_DTS_REG_OFFSET_RESET	0x34
+#define QRK_DTS_RESET_BIT		BIT(0)
+
+/* DTS enable is programmed via QRK_MBI_UNIT_RMU */
+#define QRK_DTS_REG_OFFSET_ENABLE	0xB0
+#define QRK_DTS_ENABLE_BIT		BIT(15)
+
+/* Temperature Register is read via QRK_MBI_UNIT_RMU */
+#define QRK_DTS_REG_OFFSET_TEMP		0xB1
+#define QRK_DTS_MASK_TEMP		0xFF
+#define QRK_DTS_OFFSET_TEMP		0
+#define QRK_DTS_OFFSET_REL_TEMP		16
+#define QRK_DTS_TEMP_BASE		50
+
+/* Programmable Trip Point Register is configured via QRK_MBI_UNIT_RMU */
+#define QRK_DTS_REG_OFFSET_PTPS		0xB2
+#define QRK_DTS_MASK_TP_THRES		0xFF
+#define QRK_DTS_SHIFT_TP		8
+#define QRK_DTS_ID_TP_CRITICAL		0
+#define QRK_DTS_SAFE_TP_THRES		105
+
+/* Thermal Sensor Register Lock */
+#define QRK_DTS_REG_OFFSET_LOCK		0x71
+#define QRK_DTS_LOCK_BIT		BIT(5)
+
+/* Quark DTS has 2 trip points: hot & catastrophic */
+#define QRK_MAX_DTS_TRIPS	2
+/* If DTS not locked, all trip points are configurable */
+#define QRK_DTS_WR_MASK_SET	0x3
+/* If DTS locked, all trip points are not configurable */
+#define QRK_DTS_WR_MASK_CLR	0
+
+#define DEFAULT_POLL_DELAY	2000
+
+struct soc_sensor_entry {
+	bool locked;
+	u32 store_ptps;
+	u32 store_dts_enable;
+	enum thermal_device_mode mode;
+	struct thermal_zone_device *tzone;
+};
+
+static struct soc_sensor_entry *soc_dts;
+
+static int polling_delay = DEFAULT_POLL_DELAY;
+module_param(polling_delay, int, 0644);
+MODULE_PARM_DESC(polling_delay,
+	"Polling interval for checking trip points (in milliseconds)");
+
+static DEFINE_MUTEX(dts_update_mutex);
+
+static int soc_dts_enable(struct thermal_zone_device *tzd)
+{
+	u32 out;
+	struct soc_sensor_entry *aux_entry = tzd->devdata;
+	int ret;
+
+	ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_ENABLE, &out);
+	if (ret)
+		return ret;
+
+	if (out & QRK_DTS_ENABLE_BIT) {
+		aux_entry->mode = THERMAL_DEVICE_ENABLED;
+		return 0;
+	}
+
+	if (!aux_entry->locked) {
+		out |= QRK_DTS_ENABLE_BIT;
+		ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_WRITE,
+					QRK_DTS_REG_OFFSET_ENABLE, out);
+		if (ret)
+			return ret;
+
+		aux_entry->mode = THERMAL_DEVICE_ENABLED;
+	} else {
+		aux_entry->mode = THERMAL_DEVICE_DISABLED;
+		pr_info("DTS is locked. Cannot enable DTS\n");
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int soc_dts_disable(struct thermal_zone_device *tzd)
+{
+	u32 out;
+	struct soc_sensor_entry *aux_entry = tzd->devdata;
+	int ret;
+
+	ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_ENABLE, &out);
+	if (ret)
+		return ret;
+
+	if (!(out & QRK_DTS_ENABLE_BIT)) {
+		aux_entry->mode = THERMAL_DEVICE_DISABLED;
+		return 0;
+	}
+
+	if (!aux_entry->locked) {
+		out &= ~QRK_DTS_ENABLE_BIT;
+		ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_WRITE,
+					QRK_DTS_REG_OFFSET_ENABLE, out);
+
+		if (ret)
+			return ret;
+
+		aux_entry->mode = THERMAL_DEVICE_DISABLED;
+	} else {
+		aux_entry->mode = THERMAL_DEVICE_ENABLED;
+		pr_info("DTS is locked. Cannot disable DTS\n");
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int _get_trip_temp(int trip, unsigned long *temp)
+{
+	int status;
+	u32 out;
+
+	mutex_lock(&dts_update_mutex);
+	status = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+				QRK_DTS_REG_OFFSET_PTPS, &out);
+	mutex_unlock(&dts_update_mutex);
+
+	if (status)
+		return status;
+
+	/*
+	 * Thermal Sensor Programmable Trip Point Register has 8-bit
+	 * fields for critical (catastrophic) and hot set trip point
+	 * thresholds. The threshold value is always offset by its
+	 * temperature base (50 degree Celsius).
+	 */
+	*temp = (out >> (trip * QRK_DTS_SHIFT_TP)) & QRK_DTS_MASK_TP_THRES;
+	*temp -= QRK_DTS_TEMP_BASE;
+
+	return 0;
+}
+
+static inline int sys_get_trip_temp(struct thermal_zone_device *tzd,
+				int trip, unsigned long *temp)
+{
+	return _get_trip_temp(trip, temp);
+}
+
+static inline int sys_get_crit_temp(struct thermal_zone_device *tzd,
+				unsigned long *temp)
+{
+	return _get_trip_temp(QRK_DTS_ID_TP_CRITICAL, temp);
+}
+
+static int update_trip_temp(struct soc_sensor_entry *aux_entry,
+				int trip, unsigned long temp)
+{
+	u32 out;
+	u32 temp_out;
+	u32 store_ptps;
+	int ret;
+
+	mutex_lock(&dts_update_mutex);
+	if (aux_entry->locked) {
+		ret = -EPERM;
+		goto failed;
+	}
+
+	ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+				QRK_DTS_REG_OFFSET_PTPS, &store_ptps);
+	if (ret)
+		goto failed;
+
+	/*
+	 * Protection against unsafe trip point thresdhold value.
+	 * As Quark X1000 data-sheet does not provide any recommendation
+	 * regarding the safe trip point threshold value to use, we choose
+	 * the safe value according to the threshold value set by UEFI BIOS.
+	 */
+	if (temp > QRK_DTS_SAFE_TP_THRES)
+		temp = QRK_DTS_SAFE_TP_THRES;
+
+	/*
+	 * Thermal Sensor Programmable Trip Point Register has 8-bit
+	 * fields for critical (catastrophic) and hot set trip point
+	 * thresholds. The threshold value is always offset by its
+	 * temperature base (50 degree Celsius).
+	 */
+	temp_out = temp + QRK_DTS_TEMP_BASE;
+	out = (store_ptps & ~(QRK_DTS_MASK_TP_THRES <<
+		(trip * QRK_DTS_SHIFT_TP)));
+	out |= (temp_out & QRK_DTS_MASK_TP_THRES) <<
+		(trip * QRK_DTS_SHIFT_TP);
+
+	ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_WRITE,
+				QRK_DTS_REG_OFFSET_PTPS, out);
+
+failed:
+	mutex_unlock(&dts_update_mutex);
+	return ret;
+}
+
+static inline int sys_set_trip_temp(struct thermal_zone_device *tzd, int trip,
+				unsigned long temp)
+{
+	return update_trip_temp(tzd->devdata, trip, temp);
+}
+
+static int sys_get_trip_type(struct thermal_zone_device *thermal,
+		int trip, enum thermal_trip_type *type)
+{
+	if (trip)
+		*type = THERMAL_TRIP_HOT;
+	else
+		*type = THERMAL_TRIP_CRITICAL;
+
+	return 0;
+}
+
+static int sys_get_curr_temp(struct thermal_zone_device *tzd,
+				unsigned long *temp)
+{
+	u32 out;
+	int ret;
+
+	mutex_lock(&dts_update_mutex);
+	ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_TEMP, &out);
+	mutex_unlock(&dts_update_mutex);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * Thermal Sensor Temperature Register has 8-bit field
+	 * for temperature value (offset by temperature base
+	 * 50 degree Celsius).
+	 */
+	out = (out >> QRK_DTS_OFFSET_TEMP) & QRK_DTS_MASK_TEMP;
+	*temp = out - QRK_DTS_TEMP_BASE;
+
+	return 0;
+}
+
+static int sys_get_mode(struct thermal_zone_device *tzd,
+				enum thermal_device_mode *mode)
+{
+	struct soc_sensor_entry *aux_entry = tzd->devdata;
+	*mode = aux_entry->mode;
+	return 0;
+}
+
+static int sys_set_mode(struct thermal_zone_device *tzd,
+				enum thermal_device_mode mode)
+{
+	struct soc_sensor_entry *aux_entry = tzd->devdata;
+	int ret;
+
+	mutex_lock(&dts_update_mutex);
+	if (mode == THERMAL_DEVICE_ENABLED)
+		ret = soc_dts_enable(tzd);
+	else
+		ret = soc_dts_disable(tzd);
+	mutex_unlock(&dts_update_mutex);
+
+	return ret;
+}
+
+static struct thermal_zone_device_ops tzone_ops = {
+	.get_temp = sys_get_curr_temp,
+	.get_trip_temp = sys_get_trip_temp,
+	.get_trip_type = sys_get_trip_type,
+	.set_trip_temp = sys_set_trip_temp,
+	.get_crit_temp = sys_get_crit_temp,
+	.get_mode = sys_get_mode,
+	.set_mode = sys_set_mode,
+};
+
+static void free_soc_dts(struct soc_sensor_entry *aux_entry)
+{
+	if (aux_entry) {
+		if (!aux_entry->locked) {
+			mutex_lock(&dts_update_mutex);
+			iosf_mbi_write(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_WRITE,
+					QRK_DTS_REG_OFFSET_ENABLE,
+					aux_entry->store_dts_enable);
+
+			iosf_mbi_write(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_WRITE,
+					QRK_DTS_REG_OFFSET_PTPS,
+					aux_entry->store_ptps);
+			mutex_unlock(&dts_update_mutex);
+		}
+		thermal_zone_device_unregister(aux_entry->tzone);
+		kfree(aux_entry);
+	}
+}
+
+static struct soc_sensor_entry *alloc_soc_dts(void)
+{
+	struct soc_sensor_entry *aux_entry;
+	int err;
+	u32 out;
+	int wr_mask;
+
+	aux_entry = kzalloc(sizeof(*aux_entry), GFP_KERNEL);
+	if (!aux_entry) {
+		err = -ENOMEM;
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Check if DTS register is locked */
+	err = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_LOCK,
+					&out);
+	if (err)
+		goto err_ret;
+
+	if (out & QRK_DTS_LOCK_BIT) {
+		aux_entry->locked = true;
+		wr_mask = QRK_DTS_WR_MASK_CLR;
+	} else {
+		aux_entry->locked = false;
+		wr_mask = QRK_DTS_WR_MASK_SET;
+	}
+
+	/* Store DTS default state if DTS registers are not locked */
+	if (!aux_entry->locked) {
+		/* Store DTS default enable for restore on exit */
+		err = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_ENABLE,
+					&aux_entry->store_dts_enable);
+		if (err)
+			goto err_ret;
+
+		/* Store DTS default PTPS register for restore on exit */
+		err = iosf_mbi_read(QRK_MBI_UNIT_RMU, QRK_MBI_RMU_READ,
+					QRK_DTS_REG_OFFSET_PTPS,
+					&aux_entry->store_ptps);
+		if (err)
+			goto err_ret;
+	}
+
+	aux_entry->tzone = thermal_zone_device_register("quark_dts",
+			QRK_MAX_DTS_TRIPS,
+			wr_mask,
+			aux_entry, &tzone_ops, NULL, 0, polling_delay);
+	if (IS_ERR(aux_entry->tzone)) {
+		err = PTR_ERR(aux_entry->tzone);
+		goto err_ret;
+	}
+
+	mutex_lock(&dts_update_mutex);
+	err = soc_dts_enable(aux_entry->tzone);
+	mutex_unlock(&dts_update_mutex);
+	if (err)
+		goto err_aux_status;
+
+	return aux_entry;
+
+err_aux_status:
+	thermal_zone_device_unregister(aux_entry->tzone);
+err_ret:
+	kfree(aux_entry);
+	return ERR_PTR(err);
+}
+
+static const struct x86_cpu_id qrk_thermal_ids[] __initconst  = {
+	{ X86_VENDOR_INTEL, X86_FAMILY_QUARK, X86_MODEL_QUARK_X1000 },
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, qrk_thermal_ids);
+
+static int __init intel_quark_thermal_init(void)
+{
+	int err = 0;
+
+	if (!x86_match_cpu(qrk_thermal_ids) || !iosf_mbi_available())
+		return -ENODEV;
+
+	soc_dts = alloc_soc_dts();
+	if (IS_ERR(soc_dts)) {
+		err = PTR_ERR(soc_dts);
+		goto err_free;
+	}
+
+	return 0;
+
+err_free:
+	free_soc_dts(soc_dts);
+	return err;
+}
+
+static void __exit intel_quark_thermal_exit(void)
+{
+	free_soc_dts(soc_dts);
+}
+
+module_init(intel_quark_thermal_init)
+module_exit(intel_quark_thermal_exit)
+
+MODULE_DESCRIPTION("Intel Quark DTS Thermal Driver");
+MODULE_AUTHOR("Ong Boon Leong <boon.leong.ong@xxxxxxxxx>");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
1.7.9.5

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