[PATCH 0/4] ntb: idt: Add hwmon temperature sensor interface

[PATCH 0/4] ntb: idt: Add hwmon temperature sensor interface

[Serge Semin]

IDT PCIe-switches are equipped with an embedded temperature sensor. It
works within the range [0; 127.5]C with a resolution of 0.5C. It can
be used to monitor the chip core temperature so to have prevent it from
possible overheating. It might be very topical for the chip, since it
gets heated like in hell especially if ASPM isn't enabled.

Other than the current sampled temperatur, the sensor interface exposes
history registors with lowest and highest measured temperature, thresholds
and alarm IRQs enabled/disable bits, ADC/filter settings. The device manual
states that the switch is able to generate a msi interrupt on PCIe upstreams
if the temperature crosses one of three configurable thresholds. But in
practice we discovered that the enable/disable threshold IRQs bits interface
is very broken (see the third patch commit message), so it can't be used
to create the hwmon alarm interface. As the result we had to remove the
already available temperature sensor IRQ handler and disable the corresponding
interrupt.

Current version of the driver provides following standard hwmon sysfs
files: temperature input, lowest and highest measured temperature
with possibility to reset the history, temperature offset. The rest of the
nodes can't be safely implemented for the chip due to the described issues.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

Serge Semin (4):
  ntb: idt: Alter temperature read method
  ntb: idt: Add basic hwmon sysfs interface
  ntb: idt: Discard temperature sensor IRQ handler
  ntb: idt: Alter the driver info comments

 drivers/ntb/hw/idt/Kconfig      |   4 +-
 drivers/ntb/hw/idt/ntb_hw_idt.c | 317 ++++++++++++++++++++++++++++++++++------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  87 ++++++++++-
 3 files changed, 353 insertions(+), 55 deletions(-)

-- 
2.12.0

[PATCH 1/4] ntb: idt: Alter temperature read method

[Serge Semin]

In order to create a hwmon interface for the IDT PCIe-switch temperature
sensor the already available reader method should be improved. Particularly
we need to redesign it so one would be able to read temperature/offset
values from registers of the passed types. Since IDT sensor interface
provides temperature in unsigned format 0:7:1 (7 bits for real value
and one for fraction) we also need to have helpers for the typical sysfs
temperature data type conversion to and from this format. Even though
the IDT PCIe-switch provided temperature offset got the same but signed
type it can be translated by these methods too.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 113 ++++++++++++++++++++++++++++++++++------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  56 ++++++++++++++++++++
 2 files changed, 152 insertions(+), 17 deletions(-)

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index c1d03f951b0d..928f37877790 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -1830,22 +1830,99 @@ static int idt_ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
  */
 
 /*
+ * idt_get_deg() - convert millidegree Celsius value to just degree
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: Degree corresponding to the passed millidegree value
+ */
+static inline s8 idt_get_deg(long mdegC)
+{
+	return mdegC / 1000;
+}
+
+/*
+ * idt_get_frac() - retrieve 0/0.5 fraction of the millidegree Celsius value
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: 0/0.5 degree fraction of the passed millidegree value
+ */
+static inline u8 idt_get_deg_frac(long mdegC)
+{
+	return (mdegC % 1000) >= 500 ? 5 : 0;
+}
+
+/*
+ * idt_get_temp_fmt() - convert millidegree Celsius value to 0:7:1 format
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: 0:7:1 format acceptable by the IDT temperature sensor
+ */
+static inline u8 idt_temp_get_fmt(long mdegC)
+{
+	return (idt_get_deg(mdegC) << 1) | (idt_get_deg_frac(mdegC) ? 1 : 0);
+}
+
+/*
+ * idt_get_temp_sval() - convert temp sample to signed millidegree Celsius
+ * @data:	IN - shifted to LSB 8-bits temperature sample
+ *
+ * Return: signed millidegree Celsius
+ */
+static inline long idt_get_temp_sval(u32 data)
+{
+	return ((s8)data / 2) * 1000 + (data & 0x1 ? 500 : 0);
+}
+
+/*
+ * idt_get_temp_sval() - convert temp sample to unsigned millidegree Celsius
+ * @data:	IN - shifted to LSB 8-bits temperature sample
+ *
+ * Return: unsigned millidegree Celsius
+ */
+static inline long idt_get_temp_uval(u32 data)
+{
+	return (data / 2) * 1000 + (data & 0x1 ? 500 : 0);
+}
+
+/*
  * idt_read_temp() - read temperature from chip sensor
  * @ntb:	NTB device context.
- * @val:	OUT - integer value of temperature
- * @frac:	OUT - fraction
+ * @type:	IN - type of the temperature value to read
+ * @val:	OUT - integer value of temperature in millidegree Celsius
  */
-static void idt_read_temp(struct idt_ntb_dev *ndev, unsigned char *val,
-			  unsigned char *frac)
+static void idt_read_temp(struct idt_ntb_dev *ndev,
+			  const enum idt_temp_val type, long *val)
 {
 	u32 data;
 
-	/* Read the data from TEMP field of the TMPSTS register */
-	data = idt_sw_read(ndev, IDT_SW_TMPSTS);
-	data = GET_FIELD(TMPSTS_TEMP, data);
-	/* TEMP field has one fractional bit and seven integer bits */
-	*val = data >> 1;
-	*frac = ((data & 0x1) ? 5 : 0);
+	/* Alter the temperature field in accordance with the passed type */
+	switch (type) {
+	case IDT_TEMP_CUR:
+		data = GET_FIELD(TMPSTS_TEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_LOW:
+		data = GET_FIELD(TMPSTS_LTEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_HIGH:
+		data = GET_FIELD(TMPSTS_HTEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_OFFSET:
+		/* This is the only field with signed 0:7:1 format */
+		data = GET_FIELD(TMPADJ_OFFSET,
+				 idt_sw_read(ndev, IDT_SW_TMPADJ));
+		*val = idt_get_temp_sval(data);
+		return;
+	default:
+		data = GET_FIELD(TMPSTS_TEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	}
+
+	/* The rest of the fields accept unsigned 0:7:1 format */
+	*val = idt_get_temp_uval(data);
 }
 
 /*
@@ -1861,10 +1938,10 @@ static void idt_read_temp(struct idt_ntb_dev *ndev, unsigned char *val,
  */
 static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 {
-	unsigned char val, frac;
+	unsigned long mdeg;
 
 	/* Read the current temperature value */
-	idt_read_temp(ndev, &val, &frac);
+	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
 
 	/* Read the temperature alarm to clean the alarm status out */
 	/*(void)idt_sw_read(ndev, IDT_SW_TMPALARM);*/
@@ -1876,7 +1953,8 @@ static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 		"Temp sensor IRQ detected %#08x", ntint_sts);
 
 	/* Print temperature value to log */
-	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhu.%hhu", val, frac);
+	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhd.%hhuC",
+		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 }
 
 /*=============================================================================
@@ -2124,9 +2202,9 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 				   size_t count, loff_t *offp)
 {
 	struct idt_ntb_dev *ndev = filp->private_data;
-	unsigned char temp, frac, idx, pidx, cnt;
+	unsigned char idx, pidx, cnt;
+	unsigned long irqflags, mdeg;
 	ssize_t ret = 0, off = 0;
-	unsigned long irqflags;
 	enum ntb_speed speed;
 	enum ntb_width width;
 	char *strbuf;
@@ -2275,9 +2353,10 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 	off += scnprintf(strbuf + off, size - off, "\n");
 
 	/* Current temperature */
-	idt_read_temp(ndev, &temp, &frac);
+	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
 	off += scnprintf(strbuf + off, size - off,
-		"Switch temperature\t\t- %hhu.%hhuC\n", temp, frac);
+		"Switch temperature\t\t- %hhd.%hhuC\n",
+		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 
 	/* Copy the buffer to the User Space */
 	ret = simple_read_from_buffer(ubuf, count, offp, strbuf, off);
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 856fd182f6f4..9dfd6b11a621 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -886,12 +886,42 @@
 #define IDT_SWPxMSGCTL_PART_FLD		4
 
 /*
+ * TMPCTL register fields related constants
+ * @IDT_TMPCTL_LTH_MASK:	Low temperature threshold field mask
+ * @IDT_TMPCTL_LTH_FLD:		Low temperature threshold field offset
+ * @IDT_TMPCTL_MTH_MASK:	Middle temperature threshold field mask
+ * @IDT_TMPCTL_MTH_FLD:		Middle temperature threshold field offset
+ * @IDT_TMPCTL_HTH_MASK:	High temperature threshold field mask
+ * @IDT_TMPCTL_HTH_FLD:		High temperature threshold field offset
+ * @IDT_TMPCTL_PDOWN:		Temperature sensor power down
+ */
+#define IDT_TMPCTL_LTH_MASK		0x000000FFU
+#define IDT_TMPCTL_LTH_FLD		0
+#define IDT_TMPCTL_MTH_MASK		0x0000FF00U
+#define IDT_TMPCTL_MTH_FLD		8
+#define IDT_TMPCTL_HTH_MASK		0x00FF0000U
+#define IDT_TMPCTL_HTH_FLD		16
+#define IDT_TMPCTL_PDOWN		0x80000000U
+
+/*
  * TMPSTS register fields related constants
  * @IDT_TMPSTS_TEMP_MASK:	Current temperature field mask
  * @IDT_TMPSTS_TEMP_FLD:	Current temperature field offset
  */
 #define IDT_TMPSTS_TEMP_MASK		0x000000FFU
 #define IDT_TMPSTS_TEMP_FLD		0
+#define IDT_TMPSTS_LTEMP_MASK		0x0000FF00U
+#define IDT_TMPSTS_LTEMP_FLD		8
+#define IDT_TMPSTS_HTEMP_MASK		0x00FF0000U
+#define IDT_TMPSTS_HTEMP_FLD		16
+
+/*
+ * TMPADJ register fields related constants
+ * @IDT_TMPADJ_OFFSET_MASK:	Temperature value offset field mask
+ * @IDT_TMPADJ_OFFSET_FLD:	Temperature value offset field offset
+ */
+#define IDT_TMPADJ_OFFSET_MASK		0x000000FFU
+#define IDT_TMPADJ_OFFSET_FLD		0
 
 /*
  * Helper macro to get/set the corresponding field value
@@ -951,6 +981,32 @@
 #define IDT_DIR_SIZE_ALIGN	1
 
 /*
+ * IDT PCIe-switch temperature sensor value limits
+ * @IDT_TEMP_MIN_MDEG:	Minimal integer value of temperature
+ * @IDT_TEMP_MAX_MDEG:	Maximal integer value of temperature
+ * @IDT_TEMP_MIN_OFFSET:Minimal integer value of temperature offset
+ * @IDT_TEMP_MAX_OFFSET:Maximal integer value of temperature offset
+ */
+#define IDT_TEMP_MIN_MDEG	0
+#define IDT_TEMP_MAX_MDEG	127500
+#define IDT_TEMP_MIN_OFFSET	-64000
+#define IDT_TEMP_MAX_OFFSET	63500
+
+/*
+ * Temperature sensor values enumeration
+ * @IDT_TEMP_CUR:	Current temperature
+ * @IDT_TEMP_LOW:	Lowest historical temperature
+ * @IDT_TEMP_HIGH:	Highest historical temperature
+ * @IDT_TEMP_OFFSET:	Current temperature offset
+ */
+enum idt_temp_val {
+	IDT_TEMP_CUR,
+	IDT_TEMP_LOW,
+	IDT_TEMP_HIGH,
+	IDT_TEMP_OFFSET
+};
+
+/*
  * IDT Memory Windows type. Depending on the device settings, IDT supports
  * Direct Address Translation MW registers and Lookup Table registers
  * @IDT_MW_DIR:		Direct address translation
-- 
2.12.0

[PATCH 2/4] ntb: idt: Add basic hwmon sysfs interface

[Serge Semin]

IDT PCIe switches provide an embedded temperature sensor working
within [0; 127.5]C with resolution of 0.5C. They also can generate
a PCIe upstream interrupt in case if the temperature passes through
specified thresholds. Since this thresholds interface is very broken
the created hwmon-sysfs interface exposes only the next set of hwmon
nodes: current input temperature, lowest and highest values measured,
history resetting, value offset. HWmon alarm interface isn't provided.

IDT PCIe switch also've got an ADC/filter settings of the sensor.
This driver doesn't expose them to the hwmon-sysfs interface at the
moment, except the offset node.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 182 ++++++++++++++++++++++++++++++++++++++++
 drivers/ntb/hw/idt/ntb_hw_idt.h |  24 +++++-
 2 files changed, 205 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index 928f37877790..af767a13556a 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -49,11 +49,14 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/aer.h>
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/debugfs.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
 #include <linux/ntb.h>
 
 #include "ntb_hw_idt.h"
@@ -1926,6 +1929,153 @@ static void idt_read_temp(struct idt_ntb_dev *ndev,
 }
 
 /*
+ * idt_write_temp() - write temperature to the chip sensor register
+ * @ntb:	NTB device context.
+ * @type:	IN - type of the temperature value to change
+ * @val:	IN - integer value of temperature in millidegree Celsius
+ */
+static void idt_write_temp(struct idt_ntb_dev *ndev,
+			   const enum idt_temp_val type, const long val)
+{
+	unsigned int reg;
+	u32 data;
+	u8 fmt;
+
+	/* Retrieve the properly formatted temperature value */
+	fmt = idt_temp_get_fmt(val);
+
+	mutex_lock(&ndev->hwmon_mtx);
+	switch (type) {
+	case IDT_TEMP_LOW:
+		reg = IDT_SW_TMPALARM;
+		data = SET_FIELD(TMPALARM_LTEMP, idt_sw_read(ndev, reg), fmt) &
+			~IDT_TMPALARM_IRQ_MASK;
+		break;
+	case IDT_TEMP_HIGH:
+		reg = IDT_SW_TMPALARM;
+		data = SET_FIELD(TMPALARM_HTEMP, idt_sw_read(ndev, reg), fmt) &
+			~IDT_TMPALARM_IRQ_MASK;
+		break;
+	case IDT_TEMP_OFFSET:
+		reg = IDT_SW_TMPADJ;
+		data = SET_FIELD(TMPADJ_OFFSET, idt_sw_read(ndev, reg), fmt);
+		break;
+	default:
+		goto inval_spin_unlock;
+	}
+
+	idt_sw_write(ndev, reg, data);
+
+inval_spin_unlock:
+	mutex_unlock(&ndev->hwmon_mtx);
+}
+
+/*
+ * idt_sysfs_show_temp() - printout corresponding temperature value
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_show_temp(struct device *dev,
+				   struct device_attribute *da, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+	enum idt_temp_val type = attr->index;
+	long mdeg;
+
+	idt_read_temp(ndev, type, &mdeg);
+	return sprintf(buf, "%ld\n", mdeg);
+}
+
+/*
+ * idt_sysfs_set_temp() - set corresponding temperature value
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ * @count:	Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_set_temp(struct device *dev,
+				  struct device_attribute *da, const char *buf,
+				  size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+	enum idt_temp_val type = attr->index;
+	long mdeg;
+	int ret;
+
+	ret = kstrtol(buf, 10, &mdeg);
+	if (ret)
+		return ret;
+
+	/* Clamp the passed value in accordance with the type */
+	if (type == IDT_TEMP_OFFSET)
+		mdeg = clamp_val(mdeg, IDT_TEMP_MIN_OFFSET,
+				 IDT_TEMP_MAX_OFFSET);
+	else
+		mdeg = clamp_val(mdeg, IDT_TEMP_MIN_MDEG, IDT_TEMP_MAX_MDEG);
+
+	idt_write_temp(ndev, type, mdeg);
+
+	return count;
+}
+
+/*
+ * idt_sysfs_reset_hist() - reset temperature history
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ * @count:	Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_reset_hist(struct device *dev,
+				    struct device_attribute *da,
+				    const char *buf, size_t count)
+{
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+
+	/* Just set the maximal value to the lowest temperature field and
+	 * minimal value to the highest temperature field
+	 */
+	idt_write_temp(ndev, IDT_TEMP_LOW, IDT_TEMP_MAX_MDEG);
+	idt_write_temp(ndev, IDT_TEMP_HIGH, IDT_TEMP_MIN_MDEG);
+
+	return count;
+}
+
+/*
+ * Hwmon IDT sysfs attributes
+ */
+static SENSOR_DEVICE_ATTR(temp1_input, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_CUR);
+static SENSOR_DEVICE_ATTR(temp1_lowest, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_LOW);
+static SENSOR_DEVICE_ATTR(temp1_highest, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_HIGH);
+static SENSOR_DEVICE_ATTR(temp1_offset, 0644, idt_sysfs_show_temp,
+			  idt_sysfs_set_temp, IDT_TEMP_OFFSET);
+static DEVICE_ATTR(temp1_reset_history, 0200, NULL, idt_sysfs_reset_hist);
+
+/*
+ * Hwmon IDT sysfs attributes group
+ */
+static struct attribute *idt_temp_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_lowest.dev_attr.attr,
+	&sensor_dev_attr_temp1_highest.dev_attr.attr,
+	&sensor_dev_attr_temp1_offset.dev_attr.attr,
+	&dev_attr_temp1_reset_history.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(idt_temp);
+
+/*
  * idt_temp_isr() - temperature sensor alarm events ISR
  * @ndev:	IDT NTB hardware driver descriptor
  * @ntint_sts:	NT-function interrupt status
@@ -1957,6 +2107,35 @@ static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 }
 
+/*
+ * idt_init_temp() - initialize temperature sensor interface
+ * @ndev:	IDT NTB hardware driver descriptor
+ *
+ * Simple sensor initializarion method is responsible for device switching
+ * on and resource management based hwmon interface registration. Note, that
+ * since the device is shared we won't disable it on remove, but leave it
+ * working until the system is powered off.
+ */
+static void idt_init_temp(struct idt_ntb_dev *ndev)
+{
+	struct device *hwmon;
+
+	/* Enable sensor if it hasn't been already */
+	idt_sw_write(ndev, IDT_SW_TMPCTL, 0x0);
+
+	/* Initialize hwmon interface fields */
+	mutex_init(&ndev->hwmon_mtx);
+
+	hwmon = devm_hwmon_device_register_with_groups(&ndev->ntb.pdev->dev,
+		ndev->swcfg->name, ndev, idt_temp_groups);
+	if (IS_ERR(hwmon)) {
+		dev_err(&ndev->ntb.pdev->dev, "Couldn't create hwmon device");
+		return;
+	}
+
+	dev_dbg(&ndev->ntb.pdev->dev, "Temperature HWmon interface registered");
+}
+
 /*=============================================================================
  *                           8. ISRs related operations
  *
@@ -2651,6 +2830,9 @@ static int idt_pci_probe(struct pci_dev *pdev,
 	/* Initialize Messaging subsystem */
 	idt_init_msg(ndev);
 
+	/* Initialize hwmon interface */
+	idt_init_temp(ndev);
+
 	/* Initialize IDT interrupts handler */
 	ret = idt_init_isr(ndev);
 	if (ret != 0)
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 9dfd6b11a621..032f81cb4d44 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -47,9 +47,9 @@
 #include <linux/pci_ids.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/ntb.h>
 
-
 /*
  * Macro is used to create the struct pci_device_id that matches
  * the supported IDT PCIe-switches
@@ -907,6 +907,10 @@
  * TMPSTS register fields related constants
  * @IDT_TMPSTS_TEMP_MASK:	Current temperature field mask
  * @IDT_TMPSTS_TEMP_FLD:	Current temperature field offset
+ * @IDT_TMPSTS_LTEMP_MASK:	Lowest temperature field mask
+ * @IDT_TMPSTS_LTEMP_FLD:	Lowest temperature field offset
+ * @IDT_TMPSTS_HTEMP_MASK:	Highest temperature field mask
+ * @IDT_TMPSTS_HTEMP_FLD:	Highest temperature field offset
  */
 #define IDT_TMPSTS_TEMP_MASK		0x000000FFU
 #define IDT_TMPSTS_TEMP_FLD		0
@@ -916,6 +920,20 @@
 #define IDT_TMPSTS_HTEMP_FLD		16
 
 /*
+ * TMPALARM register fields related constants
+ * @IDT_TMPALARM_LTEMP_MASK:	Lowest temperature field mask
+ * @IDT_TMPALARM_LTEMP_FLD:	Lowest temperature field offset
+ * @IDT_TMPALARM_HTEMP_MASK:	Highest temperature field mask
+ * @IDT_TMPALARM_HTEMP_FLD:	Highest temperature field offset
+ * @IDT_TMPALARM_IRQ_MASK:	Alarm IRQ status mask
+ */
+#define IDT_TMPALARM_LTEMP_MASK		0x0000FF00U
+#define IDT_TMPALARM_LTEMP_FLD		8
+#define IDT_TMPALARM_HTEMP_MASK		0x00FF0000U
+#define IDT_TMPALARM_HTEMP_FLD		16
+#define IDT_TMPALARM_IRQ_MASK		0x3F000000U
+
+/*
  * TMPADJ register fields related constants
  * @IDT_TMPADJ_OFFSET_MASK:	Temperature value offset field mask
  * @IDT_TMPADJ_OFFSET_FLD:	Temperature value offset field offset
@@ -1100,6 +1118,8 @@ struct idt_ntb_peer {
  * @msg_mask_lock:	Message mask register lock
  * @gasa_lock:		GASA registers access lock
  *
+ * @hwmon_mtx:		Temperature sensor interface update mutex
+ *
  * @dbgfs_info:		DebugFS info node
  */
 struct idt_ntb_dev {
@@ -1127,6 +1147,8 @@ struct idt_ntb_dev {
 	spinlock_t msg_mask_lock;
 	spinlock_t gasa_lock;
 
+	struct mutex hwmon_mtx;
+
 	struct dentry *dbgfs_info;
 };
 #define to_ndev_ntb(__ntb) container_of(__ntb, struct idt_ntb_dev, ntb)
-- 
2.12.0

Re: [PATCH 2/4] ntb: idt: Add basic hwmon sysfs interface

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3410 bytes --]

Hi Serge,

I love your patch! Yet something to improve:

[auto build test ERROR on ntb/ntb-next]
[also build test ERROR on v4.18-rc4 next-20180713]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Serge-Semin/ntb-idt-Add-hwmon-temperature-sensor-interface/20180714-203042
base:   https://github.com/jonmason/ntb ntb-next
config: i386-randconfig-sb0-07142045 (attached as .config)
compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 
:::::: branch date: 4 hours ago
:::::: commit date: 4 hours ago

All errors (new ones prefixed by >>):

   drivers/ntb/hw/idt/ntb_hw_idt.o: In function `idt_init_temp':
>> drivers/ntb/hw/idt/ntb_hw_idt.c:2128: undefined reference to `devm_hwmon_device_register_with_groups'

# https://github.com/0day-ci/linux/commit/e5df08844556d4987cb936b26a0423befaf2bfcc
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout e5df08844556d4987cb936b26a0423befaf2bfcc
vim +2128 drivers/ntb/hw/idt/ntb_hw_idt.c

bf2a952d Serge Semin 2017-04-12  2108  
e5df0884 Serge Semin 2018-07-14  2109  /*
e5df0884 Serge Semin 2018-07-14  2110   * idt_init_temp() - initialize temperature sensor interface
e5df0884 Serge Semin 2018-07-14  2111   * @ndev:	IDT NTB hardware driver descriptor
e5df0884 Serge Semin 2018-07-14  2112   *
e5df0884 Serge Semin 2018-07-14  2113   * Simple sensor initializarion method is responsible for device switching
e5df0884 Serge Semin 2018-07-14  2114   * on and resource management based hwmon interface registration. Note, that
e5df0884 Serge Semin 2018-07-14  2115   * since the device is shared we won't disable it on remove, but leave it
e5df0884 Serge Semin 2018-07-14  2116   * working until the system is powered off.
e5df0884 Serge Semin 2018-07-14  2117   */
e5df0884 Serge Semin 2018-07-14  2118  static void idt_init_temp(struct idt_ntb_dev *ndev)
e5df0884 Serge Semin 2018-07-14  2119  {
e5df0884 Serge Semin 2018-07-14  2120  	struct device *hwmon;
e5df0884 Serge Semin 2018-07-14  2121  
e5df0884 Serge Semin 2018-07-14  2122  	/* Enable sensor if it hasn't been already */
e5df0884 Serge Semin 2018-07-14  2123  	idt_sw_write(ndev, IDT_SW_TMPCTL, 0x0);
e5df0884 Serge Semin 2018-07-14  2124  
e5df0884 Serge Semin 2018-07-14  2125  	/* Initialize hwmon interface fields */
e5df0884 Serge Semin 2018-07-14  2126  	mutex_init(&ndev->hwmon_mtx);
e5df0884 Serge Semin 2018-07-14  2127  
e5df0884 Serge Semin 2018-07-14 @2128  	hwmon = devm_hwmon_device_register_with_groups(&ndev->ntb.pdev->dev,
e5df0884 Serge Semin 2018-07-14  2129  		ndev->swcfg->name, ndev, idt_temp_groups);
e5df0884 Serge Semin 2018-07-14  2130  	if (IS_ERR(hwmon)) {
e5df0884 Serge Semin 2018-07-14  2131  		dev_err(&ndev->ntb.pdev->dev, "Couldn't create hwmon device");
e5df0884 Serge Semin 2018-07-14  2132  		return;
e5df0884 Serge Semin 2018-07-14  2133  	}
e5df0884 Serge Semin 2018-07-14  2134  
e5df0884 Serge Semin 2018-07-14  2135  	dev_dbg(&ndev->ntb.pdev->dev, "Temperature HWmon interface registered");
e5df0884 Serge Semin 2018-07-14  2136  }
e5df0884 Serge Semin 2018-07-14  2137  

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 31948 bytes --]

Re: [PATCH 2/4] ntb: idt: Add basic hwmon sysfs interface

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 984 bytes --]

Hi Serge,

I love your patch! Yet something to improve:

[auto build test ERROR on ntb/ntb-next]
[also build test ERROR on v4.18-rc4 next-20180713]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Serge-Semin/ntb-idt-Add-hwmon-temperature-sensor-interface/20180714-203042
base:   https://github.com/jonmason/ntb ntb-next
config: x86_64-randconfig-r0-07142336 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 
:::::: branch date: 5 hours ago
:::::: commit date: 5 hours ago

All errors (new ones prefixed by >>):

>> ERROR: "devm_hwmon_device_register_with_groups" [drivers/ntb/hw/idt/ntb_hw_idt.ko] undefined!

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 27451 bytes --]

[PATCH 3/4] ntb: idt: Discard temperature sensor IRQ handler

[Serge Semin]

IDT PCIe-switch temperature sensor interface is very broken. First
of all only a few combinations of TMPCTL threshold enable bits
really cause the interrupts unmasked. Even if an individual bit
indicates the event unmasked, corresponding IRQ just isn't generated.
Most of the threshold enable bits combinations are in fact useless and
non of them can help to create a fully functional alarm interface.
So to speak, we can't create a well defined hwmon alarms based on
the IDT PCI-switch threshold IRQs.

Secondly a single threshold IRQ (not a combination of thresholds) can
be successfully enabled without the issue described above. But in this
case we experienced an enormous number of interrupts generated by
the chip if the temperature got near the enabled threshold value. Filter
adjustment didn't help much. It also doesn't provide a hysteresis settings.
Due to the temperature sample fluctuations near the threshold the
interrupts spate makes the system nearly unusable until the temperature
value finally settled so being pushed either to be fully higher or lower
the threshold.

All of these issues makes the temperature sensor alarm interface useless
and even at some point dangerous to be used in the driver. In this case
it is safer to completely discard it and disable the temperature alarm
interrupts.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 41 +----------------------------------------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  5 ++---
 2 files changed, 3 insertions(+), 43 deletions(-)

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index af767a13556a..3d48267ae315 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -2076,38 +2076,6 @@ static struct attribute *idt_temp_attrs[] = {
 ATTRIBUTE_GROUPS(idt_temp);
 
 /*
- * idt_temp_isr() - temperature sensor alarm events ISR
- * @ndev:	IDT NTB hardware driver descriptor
- * @ntint_sts:	NT-function interrupt status
- *
- * It handles events of temperature crossing alarm thresholds. Since reading
- * of TMPALARM register clears it up, the function doesn't analyze the
- * read value, instead the current temperature value just warningly printed to
- * log.
- * The method is called from PCIe ISR bottom-half routine.
- */
-static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
-{
-	unsigned long mdeg;
-
-	/* Read the current temperature value */
-	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
-
-	/* Read the temperature alarm to clean the alarm status out */
-	/*(void)idt_sw_read(ndev, IDT_SW_TMPALARM);*/
-
-	/* Clean the corresponding interrupt bit */
-	idt_nt_write(ndev, IDT_NT_NTINTSTS, IDT_NTINTSTS_TMPSENSOR);
-
-	dev_dbg(&ndev->ntb.pdev->dev,
-		"Temp sensor IRQ detected %#08x", ntint_sts);
-
-	/* Print temperature value to log */
-	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhd.%hhuC",
-		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
-}
-
-/*
  * idt_init_temp() - initialize temperature sensor interface
  * @ndev:	IDT NTB hardware driver descriptor
  *
@@ -2189,7 +2157,7 @@ static int idt_init_isr(struct idt_ntb_dev *ndev)
 		goto err_free_vectors;
 	}
 
-	/* Unmask Message/Doorbell/SE/Temperature interrupts */
+	/* Unmask Message/Doorbell/SE interrupts */
 	ntint_mask = idt_nt_read(ndev, IDT_NT_NTINTMSK) & ~IDT_NTINTMSK_ALL;
 	idt_nt_write(ndev, IDT_NT_NTINTMSK, ntint_mask);
 
@@ -2204,7 +2172,6 @@ err_free_vectors:
 	return ret;
 }
 
-
 /*
  * idt_deinit_ist() - deinitialize PCIe interrupt handler
  * @ndev:	IDT NTB hardware driver descriptor
@@ -2265,12 +2232,6 @@ static irqreturn_t idt_thread_isr(int irq, void *devid)
 		handled = true;
 	}
 
-	/* Handle temperature sensor interrupt */
-	if (ntint_sts & IDT_NTINTSTS_TMPSENSOR) {
-		idt_temp_isr(ndev, ntint_sts);
-		handled = true;
-	}
-
 	dev_dbg(&ndev->ntb.pdev->dev, "IDT IRQs 0x%08x handled", ntint_sts);
 
 	return handled ? IRQ_HANDLED : IRQ_NONE;
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 032f81cb4d44..3517cd2e2baa 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -688,15 +688,14 @@
  * @IDT_NTINTMSK_DBELL:		Doorbell interrupt mask bit
  * @IDT_NTINTMSK_SEVENT:	Switch Event interrupt mask bit
  * @IDT_NTINTMSK_TMPSENSOR:	Temperature sensor interrupt mask bit
- * @IDT_NTINTMSK_ALL:		All the useful interrupts mask
+ * @IDT_NTINTMSK_ALL:		NTB-related interrupts mask
  */
 #define IDT_NTINTMSK_MSG		0x00000001U
 #define IDT_NTINTMSK_DBELL		0x00000002U
 #define IDT_NTINTMSK_SEVENT		0x00000008U
 #define IDT_NTINTMSK_TMPSENSOR		0x00000080U
 #define IDT_NTINTMSK_ALL \
-	(IDT_NTINTMSK_MSG | IDT_NTINTMSK_DBELL | \
-	 IDT_NTINTMSK_SEVENT | IDT_NTINTMSK_TMPSENSOR)
+	(IDT_NTINTMSK_MSG | IDT_NTINTMSK_DBELL | IDT_NTINTMSK_SEVENT)
 
 /*
  * NTGSIGNAL register fields related constants
-- 
2.12.0

[PATCH 4/4] ntb: idt: Alter the driver info comments

[Serge Semin]

Since IDT PCIe-switch temperature sensor is now always available
irregardless of the EEPROM/BIOS settings, Kconfig and in-code
description should be properly altered. In addition lets update
the driver copyright lines.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/Kconfig      |  4 +---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 11 ++++++-----
 drivers/ntb/hw/idt/ntb_hw_idt.h |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/ntb/hw/idt/Kconfig b/drivers/ntb/hw/idt/Kconfig
index b360e5613b9f..bacffd369494 100644
--- a/drivers/ntb/hw/idt/Kconfig
+++ b/drivers/ntb/hw/idt/Kconfig
@@ -23,9 +23,7 @@ config NTB_IDT
 	 BAR settings of peer NT-functions, the BAR setups can't be done over
 	 kernel PCI fixups. That's why the alternative pre-initialization
 	 techniques like BIOS using SMBus interface or EEPROM should be
-	 utilized. Additionally if one needs to have temperature sensor
-	 information printed to system log, the corresponding registers must
-	 be initialized within BIOS/EEPROM as well.
+	 utilized.
 
 	 If unsure, say N.
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index 3d48267ae315..d7a4984ed423 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -4,7 +4,7 @@
  *
  *   GPL LICENSE SUMMARY
  *
- *   Copyright (C) 2016 T-Platforms All Rights Reserved.
+ *   Copyright (C) 2016-2018 T-Platforms JSC All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify it
  *   under the terms and conditions of the GNU General Public License,
@@ -1825,10 +1825,11 @@ static int idt_ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
  *                      7. Temperature sensor operations
  *
  *    IDT PCIe-switch has an embedded temperature sensor, which can be used to
- * warn a user-space of possible chip overheating. Since workload temperature
- * can be different on different platforms, temperature thresholds as well as
- * general sensor settings must be setup in the framework of BIOS/EEPROM
- * initializations. It includes the actual sensor enabling as well.
+ * check current chip core temperature. Since a workload environment can be
+ * different on different platforms, an offset and ADC/filter settings can be
+ * specified. Although the offset configuration is only exposed to the sysfs
+ * hwmon interface at the moment. The rest of the settings can be adjusted
+ * for instance by the BIOS/EEPROM firmware.
  *=============================================================================
  */
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 3517cd2e2baa..2f1aa121b0cf 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -4,7 +4,7 @@
  *
  *   GPL LICENSE SUMMARY
  *
- *   Copyright (C) 2016 T-Platforms All Rights Reserved.
+ *   Copyright (C) 2016-2018 T-Platforms JSC All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify it
  *   under the terms and conditions of the GNU General Public License,
-- 
2.12.0

[PATCH v2 0/4] ntb: idt: Add hwmon temperature sensor interface

[Serge Semin]

IDT PCIe-switches are equipped with an embedded temperature sensor. It
works within the range [0; 127.5]C with a resolution of 0.5C. It can
be used to monitor the chip core temperature so to have prevent it from
possible overheating. It might be very topical for the chip, since it
gets heated like in hell especially if ASPM isn't enabled.

Other than the current sampled temperatur, the sensor interface exposes
history registors with lowest and highest measured temperature, thresholds
and alarm IRQs enabled/disable bits, ADC/filter settings. The device manual
states that the switch is able to generate a msi interrupt on PCIe upstreams
if the temperature crosses one of three configurable thresholds. But in
practice we discovered that the enable/disable threshold IRQs bits interface
is very broken (see the third patch commit message), so it can't be used
to create the hwmon alarm interface. As the result we had to remove the
already available temperature sensor IRQ handler and disable the corresponding
interrupt.

Current version of the driver provides following standard hwmon sysfs
files: temperature input, lowest and highest measured temperature
with possibility to reset the history, temperature offset. The rest of the
nodes can't be safely implemented for the chip due to the described issues.

Changelog v2:
- Add "select HWMON" to the NTB_IDT kconfig

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

Serge Semin (4):
  ntb: idt: Alter temperature read method
  ntb: idt: Add basic hwmon sysfs interface
  ntb: idt: Discard temperature sensor IRQ handler
  ntb: idt: Alter the driver info comments

 drivers/ntb/hw/idt/Kconfig      |   4 +-
 drivers/ntb/hw/idt/ntb_hw_idt.c | 317 ++++++++++++++++++++++++++++++++++------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  87 ++++++++++-
 3 files changed, 353 insertions(+), 55 deletions(-)

-- 
2.12.0

[PATCH v2 1/4] ntb: idt: Alter temperature read method

[Serge Semin]

In order to create a hwmon interface for the IDT PCIe-switch temperature
sensor the already available reader method should be improved. Particularly
we need to redesign it so one would be able to read temperature/offset
values from registers of the passed types. Since IDT sensor interface
provides temperature in unsigned format 0:7:1 (7 bits for real value
and one for fraction) we also need to have helpers for the typical sysfs
temperature data type conversion to and from this format. Even though
the IDT PCIe-switch provided temperature offset got the same but signed
type it can be translated by these methods too.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 113 ++++++++++++++++++++++++++++++++++------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  56 ++++++++++++++++++++
 2 files changed, 152 insertions(+), 17 deletions(-)

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index dbe72f116017..c086ae5c601c 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -1829,22 +1829,99 @@ static int idt_ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
  */
 
 /*
+ * idt_get_deg() - convert millidegree Celsius value to just degree
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: Degree corresponding to the passed millidegree value
+ */
+static inline s8 idt_get_deg(long mdegC)
+{
+	return mdegC / 1000;
+}
+
+/*
+ * idt_get_frac() - retrieve 0/0.5 fraction of the millidegree Celsius value
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: 0/0.5 degree fraction of the passed millidegree value
+ */
+static inline u8 idt_get_deg_frac(long mdegC)
+{
+	return (mdegC % 1000) >= 500 ? 5 : 0;
+}
+
+/*
+ * idt_get_temp_fmt() - convert millidegree Celsius value to 0:7:1 format
+ * @mdegC:	IN - millidegree Celsius value
+ *
+ * Return: 0:7:1 format acceptable by the IDT temperature sensor
+ */
+static inline u8 idt_temp_get_fmt(long mdegC)
+{
+	return (idt_get_deg(mdegC) << 1) | (idt_get_deg_frac(mdegC) ? 1 : 0);
+}
+
+/*
+ * idt_get_temp_sval() - convert temp sample to signed millidegree Celsius
+ * @data:	IN - shifted to LSB 8-bits temperature sample
+ *
+ * Return: signed millidegree Celsius
+ */
+static inline long idt_get_temp_sval(u32 data)
+{
+	return ((s8)data / 2) * 1000 + (data & 0x1 ? 500 : 0);
+}
+
+/*
+ * idt_get_temp_sval() - convert temp sample to unsigned millidegree Celsius
+ * @data:	IN - shifted to LSB 8-bits temperature sample
+ *
+ * Return: unsigned millidegree Celsius
+ */
+static inline long idt_get_temp_uval(u32 data)
+{
+	return (data / 2) * 1000 + (data & 0x1 ? 500 : 0);
+}
+
+/*
  * idt_read_temp() - read temperature from chip sensor
  * @ntb:	NTB device context.
- * @val:	OUT - integer value of temperature
- * @frac:	OUT - fraction
+ * @type:	IN - type of the temperature value to read
+ * @val:	OUT - integer value of temperature in millidegree Celsius
  */
-static void idt_read_temp(struct idt_ntb_dev *ndev, unsigned char *val,
-			  unsigned char *frac)
+static void idt_read_temp(struct idt_ntb_dev *ndev,
+			  const enum idt_temp_val type, long *val)
 {
 	u32 data;
 
-	/* Read the data from TEMP field of the TMPSTS register */
-	data = idt_sw_read(ndev, IDT_SW_TMPSTS);
-	data = GET_FIELD(TMPSTS_TEMP, data);
-	/* TEMP field has one fractional bit and seven integer bits */
-	*val = data >> 1;
-	*frac = ((data & 0x1) ? 5 : 0);
+	/* Alter the temperature field in accordance with the passed type */
+	switch (type) {
+	case IDT_TEMP_CUR:
+		data = GET_FIELD(TMPSTS_TEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_LOW:
+		data = GET_FIELD(TMPSTS_LTEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_HIGH:
+		data = GET_FIELD(TMPSTS_HTEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	case IDT_TEMP_OFFSET:
+		/* This is the only field with signed 0:7:1 format */
+		data = GET_FIELD(TMPADJ_OFFSET,
+				 idt_sw_read(ndev, IDT_SW_TMPADJ));
+		*val = idt_get_temp_sval(data);
+		return;
+	default:
+		data = GET_FIELD(TMPSTS_TEMP,
+				 idt_sw_read(ndev, IDT_SW_TMPSTS));
+		break;
+	}
+
+	/* The rest of the fields accept unsigned 0:7:1 format */
+	*val = idt_get_temp_uval(data);
 }
 
 /*
@@ -1860,10 +1937,10 @@ static void idt_read_temp(struct idt_ntb_dev *ndev, unsigned char *val,
  */
 static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 {
-	unsigned char val, frac;
+	unsigned long mdeg;
 
 	/* Read the current temperature value */
-	idt_read_temp(ndev, &val, &frac);
+	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
 
 	/* Read the temperature alarm to clean the alarm status out */
 	/*(void)idt_sw_read(ndev, IDT_SW_TMPALARM);*/
@@ -1875,7 +1952,8 @@ static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 		"Temp sensor IRQ detected %#08x", ntint_sts);
 
 	/* Print temperature value to log */
-	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhu.%hhu", val, frac);
+	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhd.%hhuC",
+		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 }
 
 /*=============================================================================
@@ -2123,9 +2201,9 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 				   size_t count, loff_t *offp)
 {
 	struct idt_ntb_dev *ndev = filp->private_data;
-	unsigned char temp, frac, idx, pidx, cnt;
+	unsigned char idx, pidx, cnt;
+	unsigned long irqflags, mdeg;
 	ssize_t ret = 0, off = 0;
-	unsigned long irqflags;
 	enum ntb_speed speed;
 	enum ntb_width width;
 	char *strbuf;
@@ -2274,9 +2352,10 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 	off += scnprintf(strbuf + off, size - off, "\n");
 
 	/* Current temperature */
-	idt_read_temp(ndev, &temp, &frac);
+	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
 	off += scnprintf(strbuf + off, size - off,
-		"Switch temperature\t\t- %hhu.%hhuC\n", temp, frac);
+		"Switch temperature\t\t- %hhd.%hhuC\n",
+		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 
 	/* Copy the buffer to the User Space */
 	ret = simple_read_from_buffer(ubuf, count, offp, strbuf, off);
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 856fd182f6f4..9dfd6b11a621 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -886,12 +886,42 @@
 #define IDT_SWPxMSGCTL_PART_FLD		4
 
 /*
+ * TMPCTL register fields related constants
+ * @IDT_TMPCTL_LTH_MASK:	Low temperature threshold field mask
+ * @IDT_TMPCTL_LTH_FLD:		Low temperature threshold field offset
+ * @IDT_TMPCTL_MTH_MASK:	Middle temperature threshold field mask
+ * @IDT_TMPCTL_MTH_FLD:		Middle temperature threshold field offset
+ * @IDT_TMPCTL_HTH_MASK:	High temperature threshold field mask
+ * @IDT_TMPCTL_HTH_FLD:		High temperature threshold field offset
+ * @IDT_TMPCTL_PDOWN:		Temperature sensor power down
+ */
+#define IDT_TMPCTL_LTH_MASK		0x000000FFU
+#define IDT_TMPCTL_LTH_FLD		0
+#define IDT_TMPCTL_MTH_MASK		0x0000FF00U
+#define IDT_TMPCTL_MTH_FLD		8
+#define IDT_TMPCTL_HTH_MASK		0x00FF0000U
+#define IDT_TMPCTL_HTH_FLD		16
+#define IDT_TMPCTL_PDOWN		0x80000000U
+
+/*
  * TMPSTS register fields related constants
  * @IDT_TMPSTS_TEMP_MASK:	Current temperature field mask
  * @IDT_TMPSTS_TEMP_FLD:	Current temperature field offset
  */
 #define IDT_TMPSTS_TEMP_MASK		0x000000FFU
 #define IDT_TMPSTS_TEMP_FLD		0
+#define IDT_TMPSTS_LTEMP_MASK		0x0000FF00U
+#define IDT_TMPSTS_LTEMP_FLD		8
+#define IDT_TMPSTS_HTEMP_MASK		0x00FF0000U
+#define IDT_TMPSTS_HTEMP_FLD		16
+
+/*
+ * TMPADJ register fields related constants
+ * @IDT_TMPADJ_OFFSET_MASK:	Temperature value offset field mask
+ * @IDT_TMPADJ_OFFSET_FLD:	Temperature value offset field offset
+ */
+#define IDT_TMPADJ_OFFSET_MASK		0x000000FFU
+#define IDT_TMPADJ_OFFSET_FLD		0
 
 /*
  * Helper macro to get/set the corresponding field value
@@ -951,6 +981,32 @@
 #define IDT_DIR_SIZE_ALIGN	1
 
 /*
+ * IDT PCIe-switch temperature sensor value limits
+ * @IDT_TEMP_MIN_MDEG:	Minimal integer value of temperature
+ * @IDT_TEMP_MAX_MDEG:	Maximal integer value of temperature
+ * @IDT_TEMP_MIN_OFFSET:Minimal integer value of temperature offset
+ * @IDT_TEMP_MAX_OFFSET:Maximal integer value of temperature offset
+ */
+#define IDT_TEMP_MIN_MDEG	0
+#define IDT_TEMP_MAX_MDEG	127500
+#define IDT_TEMP_MIN_OFFSET	-64000
+#define IDT_TEMP_MAX_OFFSET	63500
+
+/*
+ * Temperature sensor values enumeration
+ * @IDT_TEMP_CUR:	Current temperature
+ * @IDT_TEMP_LOW:	Lowest historical temperature
+ * @IDT_TEMP_HIGH:	Highest historical temperature
+ * @IDT_TEMP_OFFSET:	Current temperature offset
+ */
+enum idt_temp_val {
+	IDT_TEMP_CUR,
+	IDT_TEMP_LOW,
+	IDT_TEMP_HIGH,
+	IDT_TEMP_OFFSET
+};
+
+/*
  * IDT Memory Windows type. Depending on the device settings, IDT supports
  * Direct Address Translation MW registers and Lookup Table registers
  * @IDT_MW_DIR:		Direct address translation
-- 
2.12.0

[PATCH v2 2/4] ntb: idt: Add basic hwmon sysfs interface

[Serge Semin]

IDT PCIe switches provide an embedded temperature sensor working
within [0; 127.5]C with resolution of 0.5C. They also can generate
a PCIe upstream interrupt in case if the temperature passes through
specified thresholds. Since this thresholds interface is very broken
the created hwmon-sysfs interface exposes only the next set of hwmon
nodes: current input temperature, lowest and highest values measured,
history resetting, value offset. HWmon alarm interface isn't provided.

IDT PCIe switch also've got an ADC/filter settings of the sensor.
This driver doesn't expose them to the hwmon-sysfs interface at the
moment, except the offset node.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---

Changelog v2:
- Add "select HWMON" to the NTB_IDT kconfig

 drivers/ntb/hw/idt/Kconfig      |   1 +
 drivers/ntb/hw/idt/ntb_hw_idt.c | 182 ++++++++++++++++++++++++++++++++++++++++
 drivers/ntb/hw/idt/ntb_hw_idt.h |  24 +++++-
 3 files changed, 206 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/hw/idt/Kconfig b/drivers/ntb/hw/idt/Kconfig
index b360e5613b9f..2ed147368fa8 100644
--- a/drivers/ntb/hw/idt/Kconfig
+++ b/drivers/ntb/hw/idt/Kconfig
@@ -1,6 +1,7 @@
 config NTB_IDT
 	tristate "IDT PCIe-switch Non-Transparent Bridge support"
 	depends on PCI
+	select HWMON
 	help
 	 This driver supports NTB of cappable IDT PCIe-switches.
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index c086ae5c601c..f12088c6a92d 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -49,11 +49,14 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/aer.h>
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/debugfs.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
 #include <linux/ntb.h>
 
 #include "ntb_hw_idt.h"
@@ -1925,6 +1928,153 @@ static void idt_read_temp(struct idt_ntb_dev *ndev,
 }
 
 /*
+ * idt_write_temp() - write temperature to the chip sensor register
+ * @ntb:	NTB device context.
+ * @type:	IN - type of the temperature value to change
+ * @val:	IN - integer value of temperature in millidegree Celsius
+ */
+static void idt_write_temp(struct idt_ntb_dev *ndev,
+			   const enum idt_temp_val type, const long val)
+{
+	unsigned int reg;
+	u32 data;
+	u8 fmt;
+
+	/* Retrieve the properly formatted temperature value */
+	fmt = idt_temp_get_fmt(val);
+
+	mutex_lock(&ndev->hwmon_mtx);
+	switch (type) {
+	case IDT_TEMP_LOW:
+		reg = IDT_SW_TMPALARM;
+		data = SET_FIELD(TMPALARM_LTEMP, idt_sw_read(ndev, reg), fmt) &
+			~IDT_TMPALARM_IRQ_MASK;
+		break;
+	case IDT_TEMP_HIGH:
+		reg = IDT_SW_TMPALARM;
+		data = SET_FIELD(TMPALARM_HTEMP, idt_sw_read(ndev, reg), fmt) &
+			~IDT_TMPALARM_IRQ_MASK;
+		break;
+	case IDT_TEMP_OFFSET:
+		reg = IDT_SW_TMPADJ;
+		data = SET_FIELD(TMPADJ_OFFSET, idt_sw_read(ndev, reg), fmt);
+		break;
+	default:
+		goto inval_spin_unlock;
+	}
+
+	idt_sw_write(ndev, reg, data);
+
+inval_spin_unlock:
+	mutex_unlock(&ndev->hwmon_mtx);
+}
+
+/*
+ * idt_sysfs_show_temp() - printout corresponding temperature value
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_show_temp(struct device *dev,
+				   struct device_attribute *da, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+	enum idt_temp_val type = attr->index;
+	long mdeg;
+
+	idt_read_temp(ndev, type, &mdeg);
+	return sprintf(buf, "%ld\n", mdeg);
+}
+
+/*
+ * idt_sysfs_set_temp() - set corresponding temperature value
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ * @count:	Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_set_temp(struct device *dev,
+				  struct device_attribute *da, const char *buf,
+				  size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+	enum idt_temp_val type = attr->index;
+	long mdeg;
+	int ret;
+
+	ret = kstrtol(buf, 10, &mdeg);
+	if (ret)
+		return ret;
+
+	/* Clamp the passed value in accordance with the type */
+	if (type == IDT_TEMP_OFFSET)
+		mdeg = clamp_val(mdeg, IDT_TEMP_MIN_OFFSET,
+				 IDT_TEMP_MAX_OFFSET);
+	else
+		mdeg = clamp_val(mdeg, IDT_TEMP_MIN_MDEG, IDT_TEMP_MAX_MDEG);
+
+	idt_write_temp(ndev, type, mdeg);
+
+	return count;
+}
+
+/*
+ * idt_sysfs_reset_hist() - reset temperature history
+ * @dev:	Pointer to the NTB device structure
+ * @da:		Sensor device attribute structure
+ * @buf:	Buffer to print temperature out
+ * @count:	Size of the passed buffer
+ *
+ * Return: Number of written symbols or negative error
+ */
+static ssize_t idt_sysfs_reset_hist(struct device *dev,
+				    struct device_attribute *da,
+				    const char *buf, size_t count)
+{
+	struct idt_ntb_dev *ndev = dev_get_drvdata(dev);
+
+	/* Just set the maximal value to the lowest temperature field and
+	 * minimal value to the highest temperature field
+	 */
+	idt_write_temp(ndev, IDT_TEMP_LOW, IDT_TEMP_MAX_MDEG);
+	idt_write_temp(ndev, IDT_TEMP_HIGH, IDT_TEMP_MIN_MDEG);
+
+	return count;
+}
+
+/*
+ * Hwmon IDT sysfs attributes
+ */
+static SENSOR_DEVICE_ATTR(temp1_input, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_CUR);
+static SENSOR_DEVICE_ATTR(temp1_lowest, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_LOW);
+static SENSOR_DEVICE_ATTR(temp1_highest, 0444, idt_sysfs_show_temp, NULL,
+			  IDT_TEMP_HIGH);
+static SENSOR_DEVICE_ATTR(temp1_offset, 0644, idt_sysfs_show_temp,
+			  idt_sysfs_set_temp, IDT_TEMP_OFFSET);
+static DEVICE_ATTR(temp1_reset_history, 0200, NULL, idt_sysfs_reset_hist);
+
+/*
+ * Hwmon IDT sysfs attributes group
+ */
+static struct attribute *idt_temp_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_lowest.dev_attr.attr,
+	&sensor_dev_attr_temp1_highest.dev_attr.attr,
+	&sensor_dev_attr_temp1_offset.dev_attr.attr,
+	&dev_attr_temp1_reset_history.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(idt_temp);
+
+/*
  * idt_temp_isr() - temperature sensor alarm events ISR
  * @ndev:	IDT NTB hardware driver descriptor
  * @ntint_sts:	NT-function interrupt status
@@ -1956,6 +2106,35 @@ static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
 		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
 }
 
+/*
+ * idt_init_temp() - initialize temperature sensor interface
+ * @ndev:	IDT NTB hardware driver descriptor
+ *
+ * Simple sensor initializarion method is responsible for device switching
+ * on and resource management based hwmon interface registration. Note, that
+ * since the device is shared we won't disable it on remove, but leave it
+ * working until the system is powered off.
+ */
+static void idt_init_temp(struct idt_ntb_dev *ndev)
+{
+	struct device *hwmon;
+
+	/* Enable sensor if it hasn't been already */
+	idt_sw_write(ndev, IDT_SW_TMPCTL, 0x0);
+
+	/* Initialize hwmon interface fields */
+	mutex_init(&ndev->hwmon_mtx);
+
+	hwmon = devm_hwmon_device_register_with_groups(&ndev->ntb.pdev->dev,
+		ndev->swcfg->name, ndev, idt_temp_groups);
+	if (IS_ERR(hwmon)) {
+		dev_err(&ndev->ntb.pdev->dev, "Couldn't create hwmon device");
+		return;
+	}
+
+	dev_dbg(&ndev->ntb.pdev->dev, "Temperature HWmon interface registered");
+}
+
 /*=============================================================================
  *                           8. ISRs related operations
  *
@@ -2650,6 +2829,9 @@ static int idt_pci_probe(struct pci_dev *pdev,
 	/* Initialize Messaging subsystem */
 	idt_init_msg(ndev);
 
+	/* Initialize hwmon interface */
+	idt_init_temp(ndev);
+
 	/* Initialize IDT interrupts handler */
 	ret = idt_init_isr(ndev);
 	if (ret != 0)
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 9dfd6b11a621..032f81cb4d44 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -47,9 +47,9 @@
 #include <linux/pci_ids.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/ntb.h>
 
-
 /*
  * Macro is used to create the struct pci_device_id that matches
  * the supported IDT PCIe-switches
@@ -907,6 +907,10 @@
  * TMPSTS register fields related constants
  * @IDT_TMPSTS_TEMP_MASK:	Current temperature field mask
  * @IDT_TMPSTS_TEMP_FLD:	Current temperature field offset
+ * @IDT_TMPSTS_LTEMP_MASK:	Lowest temperature field mask
+ * @IDT_TMPSTS_LTEMP_FLD:	Lowest temperature field offset
+ * @IDT_TMPSTS_HTEMP_MASK:	Highest temperature field mask
+ * @IDT_TMPSTS_HTEMP_FLD:	Highest temperature field offset
  */
 #define IDT_TMPSTS_TEMP_MASK		0x000000FFU
 #define IDT_TMPSTS_TEMP_FLD		0
@@ -916,6 +920,20 @@
 #define IDT_TMPSTS_HTEMP_FLD		16
 
 /*
+ * TMPALARM register fields related constants
+ * @IDT_TMPALARM_LTEMP_MASK:	Lowest temperature field mask
+ * @IDT_TMPALARM_LTEMP_FLD:	Lowest temperature field offset
+ * @IDT_TMPALARM_HTEMP_MASK:	Highest temperature field mask
+ * @IDT_TMPALARM_HTEMP_FLD:	Highest temperature field offset
+ * @IDT_TMPALARM_IRQ_MASK:	Alarm IRQ status mask
+ */
+#define IDT_TMPALARM_LTEMP_MASK		0x0000FF00U
+#define IDT_TMPALARM_LTEMP_FLD		8
+#define IDT_TMPALARM_HTEMP_MASK		0x00FF0000U
+#define IDT_TMPALARM_HTEMP_FLD		16
+#define IDT_TMPALARM_IRQ_MASK		0x3F000000U
+
+/*
  * TMPADJ register fields related constants
  * @IDT_TMPADJ_OFFSET_MASK:	Temperature value offset field mask
  * @IDT_TMPADJ_OFFSET_FLD:	Temperature value offset field offset
@@ -1100,6 +1118,8 @@ struct idt_ntb_peer {
  * @msg_mask_lock:	Message mask register lock
  * @gasa_lock:		GASA registers access lock
  *
+ * @hwmon_mtx:		Temperature sensor interface update mutex
+ *
  * @dbgfs_info:		DebugFS info node
  */
 struct idt_ntb_dev {
@@ -1127,6 +1147,8 @@ struct idt_ntb_dev {
 	spinlock_t msg_mask_lock;
 	spinlock_t gasa_lock;
 
+	struct mutex hwmon_mtx;
+
 	struct dentry *dbgfs_info;
 };
 #define to_ndev_ntb(__ntb) container_of(__ntb, struct idt_ntb_dev, ntb)
-- 
2.12.0

[PATCH v2 3/4] ntb: idt: Discard temperature sensor IRQ handler

[Serge Semin]

IDT PCIe-switch temperature sensor interface is very broken. First
of all only a few combinations of TMPCTL threshold enable bits
really cause the interrupts unmasked. Even if an individual bit
indicates the event unmasked, corresponding IRQ just isn't generated.
Most of the threshold enable bits combinations are in fact useless and
non of them can help to create a fully functional alarm interface.
So to speak, we can't create a well defined hwmon alarms based on
the IDT PCI-switch threshold IRQs.

Secondly a single threshold IRQ (not a combination of thresholds) can
be successfully enabled without the issue described above. But in this
case we experienced an enormous number of interrupts generated by
the chip if the temperature got near the enabled threshold value. Filter
adjustment didn't help much. It also doesn't provide a hysteresis settings.
Due to the temperature sample fluctuations near the threshold the
interrupts spate makes the system nearly unusable until the temperature
value finally settled so being pushed either to be fully higher or lower
the threshold.

All of these issues makes the temperature sensor alarm interface useless
and even at some point dangerous to be used in the driver. In this case
it is safer to completely discard it and disable the temperature alarm
interrupts.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 41 +----------------------------------------
 drivers/ntb/hw/idt/ntb_hw_idt.h |  5 ++---
 2 files changed, 3 insertions(+), 43 deletions(-)

diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index f12088c6a92d..55321086d59a 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -2075,38 +2075,6 @@ static struct attribute *idt_temp_attrs[] = {
 ATTRIBUTE_GROUPS(idt_temp);
 
 /*
- * idt_temp_isr() - temperature sensor alarm events ISR
- * @ndev:	IDT NTB hardware driver descriptor
- * @ntint_sts:	NT-function interrupt status
- *
- * It handles events of temperature crossing alarm thresholds. Since reading
- * of TMPALARM register clears it up, the function doesn't analyze the
- * read value, instead the current temperature value just warningly printed to
- * log.
- * The method is called from PCIe ISR bottom-half routine.
- */
-static void idt_temp_isr(struct idt_ntb_dev *ndev, u32 ntint_sts)
-{
-	unsigned long mdeg;
-
-	/* Read the current temperature value */
-	idt_read_temp(ndev, IDT_TEMP_CUR, &mdeg);
-
-	/* Read the temperature alarm to clean the alarm status out */
-	/*(void)idt_sw_read(ndev, IDT_SW_TMPALARM);*/
-
-	/* Clean the corresponding interrupt bit */
-	idt_nt_write(ndev, IDT_NT_NTINTSTS, IDT_NTINTSTS_TMPSENSOR);
-
-	dev_dbg(&ndev->ntb.pdev->dev,
-		"Temp sensor IRQ detected %#08x", ntint_sts);
-
-	/* Print temperature value to log */
-	dev_warn(&ndev->ntb.pdev->dev, "Temperature %hhd.%hhuC",
-		idt_get_deg(mdeg), idt_get_deg_frac(mdeg));
-}
-
-/*
  * idt_init_temp() - initialize temperature sensor interface
  * @ndev:	IDT NTB hardware driver descriptor
  *
@@ -2188,7 +2156,7 @@ static int idt_init_isr(struct idt_ntb_dev *ndev)
 		goto err_free_vectors;
 	}
 
-	/* Unmask Message/Doorbell/SE/Temperature interrupts */
+	/* Unmask Message/Doorbell/SE interrupts */
 	ntint_mask = idt_nt_read(ndev, IDT_NT_NTINTMSK) & ~IDT_NTINTMSK_ALL;
 	idt_nt_write(ndev, IDT_NT_NTINTMSK, ntint_mask);
 
@@ -2203,7 +2171,6 @@ static int idt_init_isr(struct idt_ntb_dev *ndev)
 	return ret;
 }
 
-
 /*
  * idt_deinit_ist() - deinitialize PCIe interrupt handler
  * @ndev:	IDT NTB hardware driver descriptor
@@ -2264,12 +2231,6 @@ static irqreturn_t idt_thread_isr(int irq, void *devid)
 		handled = true;
 	}
 
-	/* Handle temperature sensor interrupt */
-	if (ntint_sts & IDT_NTINTSTS_TMPSENSOR) {
-		idt_temp_isr(ndev, ntint_sts);
-		handled = true;
-	}
-
 	dev_dbg(&ndev->ntb.pdev->dev, "IDT IRQs 0x%08x handled", ntint_sts);
 
 	return handled ? IRQ_HANDLED : IRQ_NONE;
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 032f81cb4d44..3517cd2e2baa 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -688,15 +688,14 @@
  * @IDT_NTINTMSK_DBELL:		Doorbell interrupt mask bit
  * @IDT_NTINTMSK_SEVENT:	Switch Event interrupt mask bit
  * @IDT_NTINTMSK_TMPSENSOR:	Temperature sensor interrupt mask bit
- * @IDT_NTINTMSK_ALL:		All the useful interrupts mask
+ * @IDT_NTINTMSK_ALL:		NTB-related interrupts mask
  */
 #define IDT_NTINTMSK_MSG		0x00000001U
 #define IDT_NTINTMSK_DBELL		0x00000002U
 #define IDT_NTINTMSK_SEVENT		0x00000008U
 #define IDT_NTINTMSK_TMPSENSOR		0x00000080U
 #define IDT_NTINTMSK_ALL \
-	(IDT_NTINTMSK_MSG | IDT_NTINTMSK_DBELL | \
-	 IDT_NTINTMSK_SEVENT | IDT_NTINTMSK_TMPSENSOR)
+	(IDT_NTINTMSK_MSG | IDT_NTINTMSK_DBELL | IDT_NTINTMSK_SEVENT)
 
 /*
  * NTGSIGNAL register fields related constants
-- 
2.12.0

[PATCH v2 4/4] ntb: idt: Alter the driver info comments

[Serge Semin]

Since IDT PCIe-switch temperature sensor is now always available
irregardless of the EEPROM/BIOS settings, Kconfig and in-code
description should be properly altered. In addition lets update
the driver copyright lines.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/ntb/hw/idt/Kconfig      |  4 +---
 drivers/ntb/hw/idt/ntb_hw_idt.c | 11 ++++++-----
 drivers/ntb/hw/idt/ntb_hw_idt.h |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/ntb/hw/idt/Kconfig b/drivers/ntb/hw/idt/Kconfig
index 2ed147368fa8..f8948cf515ce 100644
--- a/drivers/ntb/hw/idt/Kconfig
+++ b/drivers/ntb/hw/idt/Kconfig
@@ -24,9 +24,7 @@ config NTB_IDT
 	 BAR settings of peer NT-functions, the BAR setups can't be done over
 	 kernel PCI fixups. That's why the alternative pre-initialization
 	 techniques like BIOS using SMBus interface or EEPROM should be
-	 utilized. Additionally if one needs to have temperature sensor
-	 information printed to system log, the corresponding registers must
-	 be initialized within BIOS/EEPROM as well.
+	 utilized.
 
 	 If unsure, say N.
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index 55321086d59a..8706b8e0864a 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -4,7 +4,7 @@
  *
  *   GPL LICENSE SUMMARY
  *
- *   Copyright (C) 2016 T-Platforms All Rights Reserved.
+ *   Copyright (C) 2016-2018 T-Platforms JSC All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify it
  *   under the terms and conditions of the GNU General Public License,
@@ -1824,10 +1824,11 @@ static int idt_ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
  *                      7. Temperature sensor operations
  *
  *    IDT PCIe-switch has an embedded temperature sensor, which can be used to
- * warn a user-space of possible chip overheating. Since workload temperature
- * can be different on different platforms, temperature thresholds as well as
- * general sensor settings must be setup in the framework of BIOS/EEPROM
- * initializations. It includes the actual sensor enabling as well.
+ * check current chip core temperature. Since a workload environment can be
+ * different on different platforms, an offset and ADC/filter settings can be
+ * specified. Although the offset configuration is only exposed to the sysfs
+ * hwmon interface at the moment. The rest of the settings can be adjusted
+ * for instance by the BIOS/EEPROM firmware.
  *=============================================================================
  */
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.h b/drivers/ntb/hw/idt/ntb_hw_idt.h
index 3517cd2e2baa..2f1aa121b0cf 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.h
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.h
@@ -4,7 +4,7 @@
  *
  *   GPL LICENSE SUMMARY
  *
- *   Copyright (C) 2016 T-Platforms All Rights Reserved.
+ *   Copyright (C) 2016-2018 T-Platforms JSC All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify it
  *   under the terms and conditions of the GNU General Public License,
-- 
2.12.0

Re: [PATCH v2 0/4] ntb: idt: Add hwmon temperature sensor interface

[Jon Mason]

On Tue, Jul 17, 2018 at 12:24:33PM +0300, Serge Semin wrote:
> IDT PCIe-switches are equipped with an embedded temperature sensor. It
> works within the range [0; 127.5]C with a resolution of 0.5C. It can
> be used to monitor the chip core temperature so to have prevent it from
> possible overheating. It might be very topical for the chip, since it
> gets heated like in hell especially if ASPM isn't enabled.
> 
> Other than the current sampled temperatur, the sensor interface exposes
> history registors with lowest and highest measured temperature, thresholds
> and alarm IRQs enabled/disable bits, ADC/filter settings. The device manual
> states that the switch is able to generate a msi interrupt on PCIe upstreams
> if the temperature crosses one of three configurable thresholds. But in
> practice we discovered that the enable/disable threshold IRQs bits interface
> is very broken (see the third patch commit message), so it can't be used
> to create the hwmon alarm interface. As the result we had to remove the
> already available temperature sensor IRQ handler and disable the corresponding
> interrupt.
> 
> Current version of the driver provides following standard hwmon sysfs
> files: temperature input, lowest and highest measured temperature
> with possibility to reset the history, temperature offset. The rest of the
> nodes can't be safely implemented for the chip due to the described issues.
> 
> Changelog v2:
> - Add "select HWMON" to the NTB_IDT kconfig
> 
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

 was waiting on you to address the kbuild errors, and it appears you
 did already.  Somehow I missed v2 of this series and just found it now.
 Sorry :(

Applied to the ntb-next branch

Thanks,
Jon

> 
> Serge Semin (4):
>   ntb: idt: Alter temperature read method
>   ntb: idt: Add basic hwmon sysfs interface
>   ntb: idt: Discard temperature sensor IRQ handler
>   ntb: idt: Alter the driver info comments
> 
>  drivers/ntb/hw/idt/Kconfig      |   4 +-
>  drivers/ntb/hw/idt/ntb_hw_idt.c | 317 ++++++++++++++++++++++++++++++++++------
>  drivers/ntb/hw/idt/ntb_hw_idt.h |  87 ++++++++++-
>  3 files changed, 353 insertions(+), 55 deletions(-)
> 
> -- 
> 2.12.0
> 

Re: [PATCH 0/4] ntb: idt: Add hwmon temperature sensor interface

[Jon Mason]

On Sat, Jul 14, 2018 at 02:58:30PM +0300, Serge Semin wrote:
> IDT PCIe-switches are equipped with an embedded temperature sensor. It
> works within the range [0; 127.5]C with a resolution of 0.5C. It can
> be used to monitor the chip core temperature so to have prevent it from
> possible overheating. It might be very topical for the chip, since it
> gets heated like in hell especially if ASPM isn't enabled.
> 
> Other than the current sampled temperatur, the sensor interface exposes
> history registors with lowest and highest measured temperature, thresholds
> and alarm IRQs enabled/disable bits, ADC/filter settings. The device manual
> states that the switch is able to generate a msi interrupt on PCIe upstreams
> if the temperature crosses one of three configurable thresholds. But in
> practice we discovered that the enable/disable threshold IRQs bits interface
> is very broken (see the third patch commit message), so it can't be used
> to create the hwmon alarm interface. As the result we had to remove the
> already available temperature sensor IRQ handler and disable the corresponding
> interrupt.
> 
> Current version of the driver provides following standard hwmon sysfs
> files: temperature input, lowest and highest measured temperature
> with possibility to reset the history, temperature offset. The rest of the
> nodes can't be safely implemented for the chip due to the described issues.
> 
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

FYI, I'm waiting on you to correct the kbuild issues.  I have been
assuming you knew this, but given the lack of follow-up patches I am
beginning to this you might believe I'm ignoring them.  I'm not :)

Thanks,
Jon

> 
> Serge Semin (4):
>   ntb: idt: Alter temperature read method
>   ntb: idt: Add basic hwmon sysfs interface
>   ntb: idt: Discard temperature sensor IRQ handler
>   ntb: idt: Alter the driver info comments
> 
>  drivers/ntb/hw/idt/Kconfig      |   4 +-
>  drivers/ntb/hw/idt/ntb_hw_idt.c | 317 ++++++++++++++++++++++++++++++++++------
>  drivers/ntb/hw/idt/ntb_hw_idt.h |  87 ++++++++++-
>  3 files changed, 353 insertions(+), 55 deletions(-)
> 
> -- 
> 2.12.0
>