This commit adds PECI cputemp hwmon driver.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Alan Cox <redacted>
Cc: Andrew Jeffery <redacted>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jason M Biils <redacted>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Miguel Ojeda <redacted>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stef van Os <redacted>
Signed-off-by: Jae Hyun Yoo <redacted>
Reviewed-by: Haiyue Wang <redacted>
Reviewed-by: James Feist <redacted>
Reviewed-by: Vernon Mauery <redacted>
Acked-by: Guenter Roeck <linux@roeck-us.net>
---
Changes since v10:
- Added Skylake Xeon D support.
- Added DTS temperature which is more thermal control friendlier than Die
   temperature.
- Fixed minor bugs and style issues.

  drivers/hwmon/Kconfig        |  14 ++
  drivers/hwmon/Makefile       |   1 +
  drivers/hwmon/peci-cputemp.c | 448 +++++++++++++++++++++++++++++++++++
  drivers/hwmon/peci-hwmon.h   |  46 ++++
  4 files changed, 509 insertions(+)
  create mode 100644 drivers/hwmon/peci-cputemp.c
  create mode 100644 drivers/hwmon/peci-hwmon.h

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 23dfe848979a..b6604759579c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig

@@ -1349,6 +1349,20 @@ config SENSORS_PCF8591
  	  These devices are hard to detect and rarely found on mainstream
  	  hardware. If unsure, say N.
  
+config SENSORS_PECI_CPUTEMP
+	tristate "PECI CPU temperature monitoring client"
+	depends on PECI
+	select MFD_INTEL_PECI_CLIENT
+	help
+	  If you say yes here you get support for the generic Intel PECI
+	  cputemp driver which provides Digital Thermal Sensor (DTS) thermal
+	  readings of the CPU package and CPU cores that are accessible using
+	  the PECI Client Command Suite via the processor PECI client.
+	  Check <file:Documentation/hwmon/peci-cputemp.rst> for details.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called peci-cputemp.
+
  source "drivers/hwmon/pmbus/Kconfig"
  
  config SENSORS_PWM_FAN

diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 6db5db9cdc29..d6fea48697af 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile

@@ -144,6 +144,7 @@ obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
  obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
  obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
  obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
+obj-$(CONFIG_SENSORS_PECI_CPUTEMP)	+= peci-cputemp.o
  obj-$(CONFIG_SENSORS_POWR1220)  += powr1220.o
  obj-$(CONFIG_SENSORS_PWM_FAN)	+= pwm-fan.o
  obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON)	+= raspberrypi-hwmon.o

diff --git a/drivers/hwmon/peci-cputemp.c b/drivers/hwmon/peci-cputemp.c
new file mode 100644
index 000000000000..70ced9f9299f
--- /dev/null
+++ b/drivers/hwmon/peci-cputemp.c

@@ -0,0 +1,448 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018-2019 Intel Corporation
+
+#include <linux/hwmon.h>
+#include <linux/jiffies.h>
+#include <linux/mfd/intel-peci-client.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include "peci-hwmon.h"
+
+#define DEFAULT_CHANNEL_NUMS   5
+#define CORETEMP_CHANNEL_NUMS  CORE_NUMS_MAX

+	/*
+	 * Processors return a value of the core DTS reading in 10.6 format
+	 * (10 bits signed decimal, 6 bits fractional).
+	 * Error codes:
+	 *   0x8000: General sensor error
+	 *   0x8001: Reserved
+	 *   0x8002: Underflow on reading value
+	 *   0x8003-0x81ff: Reserved
+	 */
+	if (core_dts_margin >= 0x8000 && core_dts_margin <= 0x81ff)
+		return -EIO;
+
+	core_dts_margin = ten_dot_six_to_millidegree(core_dts_margin);
+
+	/* Note that the tjmax should be available before calling it */
+	priv->temp.core[core_index].value = priv->temp.tjmax.value +
+					    core_dts_margin;
+
+	peci_sensor_mark_updated(&priv->temp.core[core_index]);
+
+	return 0;
+}
+
+static int cputemp_read_string(struct device *dev,
+			       enum hwmon_sensor_types type,
+			       u32 attr, int channel, const char **str)
+{
+	if (attr != hwmon_temp_label)
+		return -EOPNOTSUPP;
+
+	*str = cputemp_label[channel];
+
+	return 0;
+}
+
+static int cputemp_read(struct device *dev,
+			enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	struct peci_cputemp *priv = dev_get_drvdata(dev);
+	int ret, core_index;
+
+	if (channel >= CPUTEMP_CHANNEL_NUMS ||
+	    !(priv->temp_config[channel] & BIT(attr)))
+		return -EOPNOTSUPP;
+
+	ret = get_temp_targets(priv);
+	if (ret)
+		return ret;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		switch (channel) {
+		case channel_die:
+			ret = get_die_temp(priv);
+			if (ret)
+				break;
+
+			*val = priv->temp.die.value;
+			break;
+		case channel_dts:
+			ret = get_dts(priv);
+			if (ret)
+				break;
+
+			*val = priv->temp.dts.value;
+			break;
+		case channel_tcontrol:
+			*val = priv->temp.tcontrol.value;
+			break;
+		case channel_tthrottle:
+			*val = priv->temp.tthrottle.value;
+			break;
+		case channel_tjmax:
+			*val = priv->temp.tjmax.value;
+			break;
+		default:
+			core_index = channel - DEFAULT_CHANNEL_NUMS;
+			ret = get_core_temp(priv, core_index);
+			if (ret)
+				break;
+
+			*val = priv->temp.core[core_index].value;
+			break;
+		}
+		break;
+	case hwmon_temp_max:
+		*val = priv->temp.tcontrol.value;
+		break;
+	case hwmon_temp_crit:
+		*val = priv->temp.tjmax.value;
+		break;
+	case hwmon_temp_crit_hyst:
+		*val = priv->temp.tjmax.value - priv->temp.tcontrol.value;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+static umode_t cputemp_is_visible(const void *data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	const struct peci_cputemp *priv = data;
+
+	if (channel < ARRAY_SIZE(priv->temp_config) &&
+	    (priv->temp_config[channel] & BIT(attr)) &&
+	    (channel < DEFAULT_CHANNEL_NUMS ||
+	     (channel >= DEFAULT_CHANNEL_NUMS &&
+	      (priv->core_mask & BIT(channel - DEFAULT_CHANNEL_NUMS)))))
+		return 0444;
+
+	return 0;
+}
+
+static const struct hwmon_ops cputemp_ops = {
+	.is_visible = cputemp_is_visible,
+	.read_string = cputemp_read_string,
+	.read = cputemp_read,
+};
+
+static int check_resolved_cores(struct peci_cputemp *priv)
+{
+	struct peci_rd_pci_cfg_local_msg msg;
+	int ret;
+
+	/* Get the RESOLVED_CORES register value */
+	msg.addr = priv->mgr->client->addr;
+	msg.device = 30;
+	msg.function = 3;
+	msg.rx_len = 4;
+	msg.bus = 1;
+	msg.reg = 0xb4;
+
+	ret = peci_command(priv->mgr->client->adapter,
+			   PECI_CMD_RD_PCI_CFG_LOCAL, &msg);
+	if (msg.cc != PECI_DEV_CC_SUCCESS)
+		ret = -EAGAIN;
+	if (ret)
+		return ret;
+
+	priv->core_mask = le32_to_cpup((__le32 *)msg.pci_config);
+	if (!priv->core_mask)
+		return -EAGAIN;
+
+	dev_dbg(priv->dev, "Scanned resolved cores: 0x%llx\n", priv->core_mask);
+
+	return 0;
+}
+
+static int create_core_temp_info(struct peci_cputemp *priv)
+{
+	int ret, i;
+
+	ret = check_resolved_cores(priv);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < priv->gen_info->core_max; i++)
+		if (priv->core_mask & BIT(i))
+			while (priv->config_idx <= i + DEFAULT_CHANNEL_NUMS)
+				priv->temp_config[priv->config_idx++] =
+					config_table[channel_core];
+
+	return 0;
+}
+
+static int peci_cputemp_probe(struct platform_device *pdev)
+{
+	struct peci_client_manager *mgr = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct peci_cputemp *priv;
+	struct device *hwmon_dev;
+	int ret;
+
+	if ((mgr->client->adapter->cmd_mask &
+	    (BIT(PECI_CMD_GET_TEMP) | BIT(PECI_CMD_RD_PKG_CFG))) !=
+	    (BIT(PECI_CMD_GET_TEMP) | BIT(PECI_CMD_RD_PKG_CFG)))
+		return -ENODEV;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, priv);
+	priv->mgr = mgr;
+	priv->dev = dev;
+	priv->gen_info = mgr->gen_info;
+
+	snprintf(priv->name, PECI_NAME_SIZE, "peci_cputemp.cpu%d",
+		 mgr->client->addr - PECI_BASE_ADDR);
+
+	priv->temp_config[priv->config_idx++] = config_table[channel_die];
+	priv->temp_config[priv->config_idx++] = config_table[channel_dts];
+	priv->temp_config[priv->config_idx++] = config_table[channel_tcontrol];
+	priv->temp_config[priv->config_idx++] = config_table[channel_tthrottle];
+	priv->temp_config[priv->config_idx++] = config_table[channel_tjmax];
+
+	ret = create_core_temp_info(priv);
+	if (ret)
+		dev_dbg(dev, "Skipped creating core temp info\n");
+
+	priv->chip.ops = &cputemp_ops;
+	priv->chip.info = priv->info;
+
+	priv->info[0] = &priv->temp_info;
+
+	priv->temp_info.type = hwmon_temp;
+	priv->temp_info.config = priv->temp_config;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(priv->dev,
+							 priv->name,
+							 priv,
+							 &priv->chip,
+							 NULL);
+
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	dev_dbg(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), priv->name);
+
+	return 0;
+}
+
+static const struct platform_device_id peci_cputemp_ids[] = {
+	{ .name = "peci-cputemp", .driver_data = 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, peci_cputemp_ids);
+
+static struct platform_driver peci_cputemp_driver = {
+	.probe    = peci_cputemp_probe,
+	.id_table = peci_cputemp_ids,
+	.driver   = { .name = KBUILD_MODNAME, },
+};
+module_platform_driver(peci_cputemp_driver);
+
+MODULE_AUTHOR("Jae Hyun Yoo [off-list ref]");
+MODULE_DESCRIPTION("PECI cputemp driver");
+MODULE_LICENSE("GPL v2");

diff --git a/drivers/hwmon/peci-hwmon.h b/drivers/hwmon/peci-hwmon.h
new file mode 100644
index 000000000000..e0e3c901c6e4
--- /dev/null
+++ b/drivers/hwmon/peci-hwmon.h

@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018-2019 Intel Corporation */
+
+#ifndef __PECI_HWMON_H
+#define __PECI_HWMON_H
+
+#include <linux/peci.h>
+
+#define TEMP_TYPE_PECI   6 /* Sensor type 6: Intel PECI */
+#define UPDATE_INTERVAL  HZ
+
+/**
+ * struct peci_sensor_data - PECI sensor information
+ * @valid: flag to indicate the sensor value is valid
+ * @value: sensor value in millidegree Celsius
+ * @last_updated: time of the last update in jiffies
+ */
+struct peci_sensor_data {
+	uint  valid;
+	s32   value;
+	ulong last_updated;
+};
+
+/**
+ * peci_sensor_need_update - check whether sensor update is needed or not
+ * @sensor: pointer to sensor data struct
+ *
+ * Return: true if update is needed, false if not.
+ */
+static inline bool peci_sensor_need_update(struct peci_sensor_data *sensor)
+{
+	return !sensor->valid ||
+	       time_after(jiffies, sensor->last_updated + UPDATE_INTERVAL);
+}
+
+/**
+ * peci_sensor_mark_updated - mark the sensor is updated
+ * @sensor: pointer to sensor data struct
+ */
+static inline void peci_sensor_mark_updated(struct peci_sensor_data *sensor)
+{
+	sensor->valid = 1;
+	sensor->last_updated = jiffies;
+}
+
+#endif /* __PECI_HWMON_H */