hwmon: Add driver for AMD family 15h processor power information

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_crit (ProcessorPwrWatts)
* power1_input (CurrPwrWatts)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 240 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 511f1f4802f1..567dfae94bbc 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -248,6 +248,16 @@ 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 28e8d52f6379..8524db270bf0 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -48,6 +48,7 @@ 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 000000000000..523f8fb9e7d9
--- /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_watts;
+        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 = dev_get_drvdata(dev);
+
+        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_watts;
+
+        /*
+         * 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_crit(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+        struct fam15h_power_data *data = dev_get_drvdata(dev);
+
+        return sprintf(buf, "%u\n", data->processor_pwr_watts);
+}
+static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, 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_crit.attr,
+        &dev_attr_name.attr,
+        NULL
+};
+
+static const 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_watts = ((val & 0x3ff) << 6) | ((val >> 10) & 0x3f);
+        tmp *= data->tdp_to_watts;
+
+        /* 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;
+
+        dev_set_drvdata(dev, data);
+        err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
+        if (err)
+                goto exit_free_data;
+
+        data->hwmon_dev = hwmon_device_register(dev);
+        if (IS_ERR(data->hwmon_dev)) {
+                err = PTR_ERR(data->hwmon_dev);
+                goto exit_remove_group;
+        }
+
+        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;
+
+        dev = &pdev->dev;
+        data = dev_get_drvdata(dev);
+        hwmon_device_unregister(data->hwmon_dev);
+        sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
+        dev_set_drvdata(dev, 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)