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AMD K8 digital sensor - take2

PATCH New Rudolf Marek 3 participants 4 messages Aug 22, 2006 – Aug 23, 2006

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#0 lore raw

PATCH 1/1 AMD K8 digital sensor - take2

Hello Jean,

This patch adds support for the temperature sensor(s) found in AMD K8 CPUs.

Signed-off-by Rudolf Marek <r.marek at sh.cvut.cz>

All fixed & tested on quad CPU - dual dual core ;), please apply.

regards
Rudolf
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#1 lore raw

PATCH 1/1 AMD K8 digital sensor - take2

Hi Rudolf,

Quoted 7 lines · Rudolf Marek

Hello Jean,

This patch adds support for the temperature sensor(s) found in AMD K8 CPUs.

Signed-off-by Rudolf Marek <r.marek at sh.cvut.cz>

All fixed & tested on quad CPU - dual dual core ;), please apply.

This line has me thinking...
+ u32 temp[2][2]; /* core, place */

AMD and Intel are both coming out with quad-core processors soon. Some could be backward-compatible with existing dual-core sockets. In addition, some servers have four sockets (quad processor, or 8-core, etc.).

Maybe this array should be a little bigger? It will save you some trouble later. If not, it's okay to ignore this message...

HTH,
David

#2 lore raw

PATCH 1/1 AMD K8 digital sensor - take2

In reply to Rudolf Marek

Hi David,

Quoted 8 lines

This line has me thinking...
+ u32 temp[2][2]; /* core, place */

AMD and Intel are both coming out with quad-core processors soon. Some could be backward-compatible with existing dual-core sockets. In addition, some servers have four sockets (quad processor, or 8-core, etc.).

Four sockets are ok. It will appear as 4 devices, so 4 instances of this driver ;)

Quoted 2 lines

Maybe this array should be a little bigger? It will save you some trouble later. If not, it's okay to ignore this message...

Well I dont know how to switch between more than two cores anyway. The driver should handle 4temps/physical CPU.

regards
Rudolf

#3 lore raw

PATCH 1/1 AMD K8 digital sensor - take2

In reply to Rudolf Marek

Rudolf,

Quoted 5 lines

This patch adds support for the temperature sensor(s) found in AMD K8 CPUs.

Signed-off-by Rudolf Marek <r.marek at sh.cvut.cz>

All fixed & tested on quad CPU - dual dual core ;), please apply.

Sorry I still have some comments on the code...

Quoted 1 line

+#define TEMP_FROM_REG(val) ((((val >> 16) & 0xFF) - 49) * 1000)

Missing parentheses around "val".

Review

Quoted 4 lines
(quoted diff) +4 -0
+#define REG_TEMP	0xe4
+#define REG_TEMP_T	0xe6
+#define PLACE	0x40
+#define CORE	0x04

The names you chose for the register names are almost similar, it's confusing. In fact it's so confusing that I thought your code below was broken. Please find better names. Either make it clear which is the temperature value register and which is the core/sensor selection register, or don't define REG_TEMP_T at all.

While you're there it would be nice to properly align all the values. And maybe find a common prefix to PLACE and CORE to make it clear they refer to the sensor selection register (SEL_PLACE and SEL_CORE, maybe?)

Quoted 14 lines
(quoted diff) +14 -0
+
+struct k8temp_data {
+	struct class_device *class_dev;
+	struct mutex update_lock;
+	const char *name;
+	char valid;		/* zero until following fields are valid */
+	unsigned long last_updated;	/* in jiffies */
+
+	/* registers values */
+	u8 sensorsp;		/* sensor presence bits - CORE & PLACE */
+	u32 temp[2][2];		/* core, place */
+};
+
+static struct k8temp_data *k8temp_update_device(struct device *dev)

Review

Quoted 10 lines
(quoted diff) +10 -0
+{
+	struct k8temp_data *data = dev_get_drvdata(dev);
+	struct pci_dev *pdev = to_pci_dev(dev);
+	u8 tmp;
+
+	mutex_lock(&data->update_lock);
+
+	if (!data->valid
+	    || time_after(jiffies, data->last_updated + HZ)) {
+		dev_dbg(&pdev->dev, "Updating k8temp data.\n");

You can use "dev" directly. BTW I really wonder what is the point of this debug message. I know we have it in many other hardware monitoring drivers, but is it really useful? We pretty well know when the data is updated.

Review

Quoted 5 lines
(quoted diff) +5 -0
+
+		pci_read_config_byte(pdev, REG_TEMP, &tmp);
+		tmp &= ~(PLACE | CORE);		/* Select sensor 0, core0 */
+		pci_write_config_byte(pdev, REG_TEMP, tmp);
+		pci_read_config_dword(pdev, REG_TEMP, &data->temp[0][0]);

I found it very confusing to see you read the sensor selection and the temperature value from the same register, until I realized there was a byte read and a dword read and you are then using some masking/shifting to extract the part you need.

Why don't you make a _word_ read from REG_TEMP_T (0xe6) instead? This would be much clearer. At any rate, defining REG_TEMP_T and using it only during the initialization step is very confusing.

Quoted 202 lines
(quoted diff) +202 -0
+
+		if (data->sensorsp & PLACE) {
+			tmp |= PLACE;	/* Select sensor 1, core0 */
+			pci_write_config_byte(pdev, REG_TEMP, tmp);
+			pci_read_config_dword(pdev, REG_TEMP,
+					      &data->temp[0][1]);
+		}
+
+		if (data->sensorsp & CORE) {
+			tmp &= ~PLACE;	/* Select sensor 0, core1 */
+			tmp |= CORE;
+			pci_write_config_byte(pdev, REG_TEMP, tmp);
+			pci_read_config_dword(pdev, REG_TEMP,
+					      &data->temp[1][0]);
+
+			if (data->sensorsp & PLACE) {
+				tmp |= PLACE;	/* Select sensor 1, core1 */
+				pci_write_config_byte(pdev, REG_TEMP, tmp);
+				pci_read_config_dword(pdev, REG_TEMP,
+						      &data->temp[1][1]);
+			}
+		}
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+	return data;
+}
+
+/*
+ * Sysfs stuff
+ */
+
+static ssize_t show_name(struct device *dev, struct device_attribute
+			 *devattr, char *buf)
+{
+	struct k8temp_data *data = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", data->name);
+}
+
+
+static ssize_t show_temp(struct device *dev,
+			 struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute_2 *attr > +	    to_sensor_dev_attr_2(devattr);
+	int core = attr->nr;
+	int place = attr->index;
+	struct k8temp_data *data = k8temp_update_device(dev);
+	
+	return sprintf(buf, "%d\n",
+		       TEMP_FROM_REG(data->temp[core][place]));
+}
+
+/* core, place */
+
+static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp, NULL, 0, 0);
+static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp, NULL, 0, 1);
+static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp, NULL, 1, 0);
+static SENSOR_DEVICE_ATTR_2(temp4_input, S_IRUGO, show_temp, NULL, 1, 1);
+static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+
+static struct pci_device_id k8temp_ids[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
+	{ 0 },
+};
+
+static int __devinit k8temp_probe(struct pci_dev *pdev,
+				  const struct pci_device_id *id)
+{
+	int err;
+	u8 scfg, temp;
+	struct k8temp_data *data;
+	u32 cpuid = cpuid_eax(1);
+
+	/* this feature should be available since SH-C0 core */
+	if ((cpuid = 0xf40) || (cpuid = 0xf50) || (cpuid = 0xf51)) {
+		err = -ENODEV;
+		goto exit;
+	}
+
+	if (!(data = kzalloc(sizeof(struct k8temp_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	pci_read_config_byte(pdev, REG_TEMP, &scfg);
+	scfg &= ~(PLACE | CORE);		/* Select sensor 0, core0 */
+	pci_write_config_byte(pdev, REG_TEMP, scfg);
+	pci_read_config_byte(pdev, REG_TEMP, &scfg);
+
+	if (scfg & (PLACE | CORE)) {
+		dev_err(&pdev->dev, "Configuration bit(s) stuck at 1!\n");
+		err = -ENODEV;
+		goto exit_free;
+	}
+
+	scfg |= (PLACE | CORE);
+	pci_write_config_byte(pdev, REG_TEMP, scfg);
+
+	/* now we know if we can change core and/or sensor */
+	pci_read_config_byte(pdev, REG_TEMP, &data->sensorsp);
+
+	if (data->sensorsp & PLACE) {
+		scfg &= ~CORE;	/* Select sensor 1, core0 */
+		pci_write_config_byte(pdev, REG_TEMP, scfg);
+		pci_read_config_byte(pdev, REG_TEMP_T, &temp);
+		scfg |= CORE;	/* prepare for next selection */
+		if (!temp)	/* if temp is 0 -49C is not likely */
+			data->sensorsp &= ~PLACE;
+	}
+
+	if (data->sensorsp & CORE) {
+		scfg &= ~PLACE;	/* Select sensor 0, core1 */
+		pci_write_config_byte(pdev, REG_TEMP, scfg);
+		pci_read_config_byte(pdev, REG_TEMP_T, &temp);
+		if (!temp)	/* if temp is 0 -49C is not likely */
+			data->sensorsp &= ~CORE;
+	}
+
+	data->name = "k8temp";
+	mutex_init(&data->update_lock);
+	dev_set_drvdata(&pdev->dev, data);
+
+	/* Register sysfs hooks */
+	err = device_create_file(&pdev->dev,
+			   &sensor_dev_attr_temp1_input.dev_attr);
+	if (err)
+		goto exit_remove;
+
+	/* sensor can be changed and reports something */
+	if (data->sensorsp & PLACE) {
+		err = device_create_file(&pdev->dev,
+				   &sensor_dev_attr_temp2_input.dev_attr);
+		if (err)
+			goto exit_remove;
+	}
+
+	/* core can be changed and reports something */
+	if (data->sensorsp & CORE) {
+		err = device_create_file(&pdev->dev,
+				   &sensor_dev_attr_temp3_input.dev_attr);
+		if (err)
+			goto exit_remove;
+		if (data->sensorsp & PLACE)
+			err = device_create_file(&pdev->dev,
+					   &sensor_dev_attr_temp4_input.
+					   dev_attr);
+			if (err)
+				goto exit_remove;
+	}
+
+	err = device_create_file(&pdev->dev, &dev_attr_name);
+	if (err)
+		goto exit_remove;
+
+	data->class_dev = hwmon_device_register(&pdev->dev);
+
+	if (IS_ERR(data->class_dev)) {
+		err = PTR_ERR(data->class_dev);
+		goto exit_remove;
+	}
+
+	return 0;
+
+exit_remove:
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp1_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp2_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp3_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp4_input.dev_attr);
+	device_remove_file(&pdev->dev, &dev_attr_name);	
+exit_free:
+	dev_set_drvdata(&pdev->dev, NULL);
+	kfree(data);
+exit:
+	return err;
+}
+
+static void __devexit k8temp_remove(struct pci_dev *pdev)
+{
+	struct k8temp_data *data = dev_get_drvdata(&pdev->dev);
+
+	hwmon_device_unregister(data->class_dev);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp1_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp2_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp3_input.dev_attr);
+	device_remove_file(&pdev->dev,
+			   &sensor_dev_attr_temp4_input.dev_attr);
+	device_remove_file(&pdev->dev, &dev_attr_name);
+	dev_set_drvdata(&pdev->dev, NULL);
+	kfree(data);
+}
+

Review

Quoted 10 lines
(quoted diff) +10 -0
+static struct pci_driver k8temp_driver = {
+	.name = "k8temp",
+	.id_table = k8temp_ids,
+	.probe = k8temp_probe,
+	.remove = __devexit_p(k8temp_remove),
+};
+
+static int __init k8temp_init(void)
+{
+	return pci_module_init(&k8temp_driver);

Deprecated, please use pci_register_driver instead. I was going to fix it myself, but since we'll need one more iteration anyway...

Quoted 14 lines
(quoted diff) +13 -0
+}
+
+static void __exit k8temp_exit(void)
+{
+	pci_unregister_driver(&k8temp_driver);
+}
+
+MODULE_AUTHOR("Rudolf Marek <r.marek at sh.cvut.cz>");
+MODULE_DESCRIPTION("AMD K8 core temperature monitor");
+MODULE_LICENSE("GPL");
+
+module_init(k8temp_init)
+module_exit(k8temp_exit)
Signature · 1 line
Jean Delvare