[PATCH v4] hwmon: Add driver for AMD family 15h processor power information

[Andreas Herrmann <herrmann.der.user@googlemail.com>]

From: Andreas Herrmann <andreas.herrmann3@amd.com>

This CPU family provides NB register values to gather following
TDP information

* ProcessorPwrWatts: Specifies in Watts the maximum amount of power
  the processor can support.
* CurrPwrWatts: Specifies in Watts the current amount of power being
  consumed by the processor.

This driver provides

* power1_max (ProcessorPwrWatts)
* power1_input (CurrPwrWatts)

Changes from v2:
 - fix format strings
 - removed paranoid checks for existense of functions 3 and 5
 - changed return type of function f15h_power_is_internal_node0
 - use power1_max instead of power1_cap
 - use dev_warn instead of WARN_ON
 - rebased against 2.6.39-rc2
 - added Documentation/hwmon/f15h_power

Changes from v3:
 - read static power information only once (during driver initialization)
 - made use of attribute groups
 - renamed f15h_power to fam15h_power

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
 Documentation/hwmon/fam15h_power |   37 ++++++
 drivers/hwmon/Kconfig            |   10 ++
 drivers/hwmon/Makefile           |    1 +
 drivers/hwmon/fam15h_power.c     |  229 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 277 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/hwmon/fam15h_power
 create mode 100644 drivers/hwmon/fam15h_power.c

At this stage I consider the _max attribute as the right one for
reporting ProcessorPwrWatts.

Hopefully I've addressed all your coments.
Please apply.


Thanks,

Andreas

diff --git a/Documentation/hwmon/fam15h_power b/Documentation/hwmon/fam15h_power
new file mode 100644
index 0000000..2f4d291
--- /dev/null
+++ b/Documentation/hwmon/fam15h_power
@@ -0,0 +1,37 @@
+Kernel driver fam15h_power
+==========================
+
+Supported chips:
+* AMD Family 15h Processors
+
+  Prefix: 'fam15h_power'
+  Addresses scanned: PCI space
+  Datasheets:
+  BIOS and Kernel Developer's Guide (BKDG) For AMD Family 15h Processors
+    (not yet published)
+
+Author: Andreas Herrmann <andreas.herrmann3@amd.com>
+
+Description
+-----------
+
+This driver permits reading of registers providing power information
+of AMD Family 15h processors.
+
+For AMD Family 15h processors the following power values can be
+calculated using different processor northbridge function registers:
+
+* BasePwrWatts: Specifies in watts the maximum amount of power
+  consumed by the processor for NB and logic external to the core.
+* ProcessorPwrWatts: Specifies in watts the maximum amount of power
+  the processor can support.
+* CurrPwrWatts: Specifies in watts the current amount of power being
+  consumed by the processor.
+
+This driver provides ProcessorPwrWatts and CurrPwrWatts:
+* power1_max (ProcessorPwrWatts)
+* power1_input (CurrPwrWatts)
+
+On multi-node processors the calculated value is for the entire
+package and not for a single node. Thus the driver creates sysfs
+attributes only for internal node0 of a multi-node processor.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 060ef63..fb3e334 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -249,6 +249,16 @@ config SENSORS_K10TEMP
 	  This driver can also be built as a module.  If so, the module
 	  will be called k10temp.
 
+config SENSORS_FAM15H_POWER
+	tristate "AMD Family 15h processor power"
+	depends on X86 && PCI
+	help
+	  If you say yes here you get support for processor power
+	  information of your AMD family 15h CPU.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called fam15h_power.
+
 config SENSORS_ASB100
 	tristate "Asus ASB100 Bach"
 	depends on X86 && I2C && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 967d0ea..236d3f9 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
 obj-$(CONFIG_SENSORS_F71805F)	+= f71805f.o
 obj-$(CONFIG_SENSORS_F71882FG)	+= f71882fg.o
 obj-$(CONFIG_SENSORS_F75375S)	+= f75375s.o
+obj-$(CONFIG_SENSORS_FAM15H_POWER) += fam15h_power.o
 obj-$(CONFIG_SENSORS_FSCHMD)	+= fschmd.o
 obj-$(CONFIG_SENSORS_G760A)	+= g760a.o
 obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
new file mode 100644
index 0000000..cb6eb99
--- /dev/null
+++ b/drivers/hwmon/fam15h_power.c
@@ -0,0 +1,229 @@
+/*
+ * fam15h_power.c - AMD Family 15h processor power monitoring
+ *
+ * Copyright (c) 2011 Advanced Micro Devices, Inc.
+ * Author: Andreas Herrmann <andreas.herrmann3@amd.com>
+ *
+ *
+ * This driver is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This driver is distributed in the hope that 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this driver; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/bitops.h>
+#include <asm/processor.h>
+
+MODULE_DESCRIPTION("AMD Family 15h CPU processor power monitor");
+MODULE_AUTHOR("Andreas Herrmann <andreas.herrmann3@amd.com>");
+MODULE_LICENSE("GPL");
+
+/* D18F3 */
+#define REG_NORTHBRIDGE_CAP		0xe8
+
+/* D18F4 */
+#define REG_PROCESSOR_TDP		0x1b8
+
+/* D18F5 */
+#define REG_TDP_RUNNING_AVERAGE		0xe0
+#define REG_TDP_LIMIT3			0xe8
+
+struct fam15h_power_data {
+	struct device *hwmon_dev;
+	unsigned int tdp_to_watt;
+	unsigned int base_tdp;
+	unsigned int processor_pwr_watts;
+};
+
+static ssize_t show_power(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	u32 val, tdp_limit, running_avg_range;
+	s32 running_avg_capture;
+	u64 curr_pwr_watts;
+	struct pci_dev *f4 = to_pci_dev(dev);
+	struct fam15h_power_data *data = pci_get_drvdata(f4);
+
+	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
+				  REG_TDP_RUNNING_AVERAGE, &val);
+	running_avg_capture = (val >> 4) & 0x3fffff;
+	running_avg_capture = sign_extend32(running_avg_capture, 22);
+	running_avg_range = val & 0xf;
+
+	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
+				  REG_TDP_LIMIT3, &val);
+
+	tdp_limit = val >> 16;
+	curr_pwr_watts = tdp_limit  + data->base_tdp -
+		(s32)(running_avg_capture >> (running_avg_range + 1));
+	curr_pwr_watts *= data->tdp_to_watt;
+
+	/*
+	 * Convert to microWatt
+	 *
+	 * power is in Watt provided as fixed point integer with
+	 * scaling factor 1/(2^16).  For conversion we use
+	 * (10^6)/(2^16) = 15625/(2^10)
+	 */
+	curr_pwr_watts = (curr_pwr_watts * 15625) >> 10;
+	return sprintf(buf, "%u\n", (unsigned int) curr_pwr_watts);
+}
+static DEVICE_ATTR(power1_input, S_IRUGO, show_power, NULL);
+
+static ssize_t show_power_max(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *f4 = to_pci_dev(dev);
+	struct fam15h_power_data *data = pci_get_drvdata(f4);
+
+	return sprintf(buf, "%u\n", data->processor_pwr_watts);
+}
+static DEVICE_ATTR(power1_max, S_IRUGO, show_power_max, NULL);
+
+static ssize_t show_name(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "fam15h_power\n");
+}
+static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+
+static struct attribute *fam15h_power_attrs[] = {
+	&dev_attr_power1_input.attr,
+	&dev_attr_power1_max.attr,
+	&dev_attr_name.attr,
+	NULL
+};
+
+static struct attribute_group fam15h_power_attr_group = {
+	.attrs	= fam15h_power_attrs,
+};
+
+static bool __devinit fam15h_power_is_internal_node0(struct pci_dev *f4)
+{
+	u32 val;
+
+	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 3),
+				  REG_NORTHBRIDGE_CAP, &val);
+	if ((val & BIT(29)) && ((val >> 30) & 3))
+		return false;
+
+	return true;
+}
+
+static void __devinit fam15h_power_init_data(struct pci_dev *f4,
+					     struct fam15h_power_data *data)
+{
+	u32 val;
+	u64 tmp;
+
+	pci_read_config_dword(f4, REG_PROCESSOR_TDP, &val);
+	data->base_tdp = val >> 16;
+	tmp = val & 0xffff;
+
+	pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
+				  REG_TDP_LIMIT3, &val);
+
+	data->tdp_to_watt = ((val & 0x3ff) << 6) | ((val >> 10) & 0x3f);
+	tmp *= data->tdp_to_watt;
+
+	/* result not allowed to be >= 256W */
+	if ((tmp>>16) >= 256)
+		dev_warn(&f4->dev, "Bogus value for ProcessorPwrWatts "
+			 "(processor_pwr_watts>=%u)\n",
+			 (unsigned int) (tmp >> 16));
+
+	/* convert to microWatt */
+	data->processor_pwr_watts = (tmp * 15625) >> 10;
+}
+
+static int __devinit fam15h_power_probe(struct pci_dev *pdev,
+					const struct pci_device_id *id)
+{
+	struct fam15h_power_data *data;
+	struct device *dev;
+	int err;
+
+	if (!fam15h_power_is_internal_node0(pdev)) {
+		err = -ENODEV;
+		goto exit;
+	}
+
+	data = kzalloc(sizeof(struct fam15h_power_data), GFP_KERNEL);
+	if (!data) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	fam15h_power_init_data(pdev, data);
+
+	dev = &pdev->dev;
+	err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
+	if (err)
+		goto exit_free_data;
+
+	data->hwmon_dev = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		goto exit_remove_group;
+	}
+	pci_set_drvdata(pdev, data);
+
+	return 0;
+
+exit_remove_group:
+	sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
+exit_free_data:
+	kfree(data);
+exit:
+	return err;
+}
+
+static void __devexit fam15h_power_remove(struct pci_dev *pdev)
+{
+	struct device *dev;
+	struct fam15h_power_data *data = pci_get_drvdata(pdev);
+
+	dev = &pdev->dev;
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
+	pci_set_drvdata(pdev, NULL);
+	kfree(data);
+}
+
+static DEFINE_PCI_DEVICE_TABLE(fam15h_power_id_table) = {
+	{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
+	{}
+};
+MODULE_DEVICE_TABLE(pci, fam15h_power_id_table);
+
+static struct pci_driver fam15h_power_driver = {
+	.name = "fam15h_power",
+	.id_table = fam15h_power_id_table,
+	.probe = fam15h_power_probe,
+	.remove = __devexit_p(fam15h_power_remove),
+};
+
+static int __init fam15h_power_init(void)
+{
+	return pci_register_driver(&fam15h_power_driver);
+}
+
+static void __exit fam15h_power_exit(void)
+{
+	pci_unregister_driver(&fam15h_power_driver);
+}
+
+module_init(fam15h_power_init)
+module_exit(fam15h_power_exit)
-- 
1.7.4.1