linux/drivers/hwmon/fam15h_power.c
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   1/*
   2 * fam15h_power.c - AMD Family 15h processor power monitoring
   3 *
   4 * Copyright (c) 2011 Advanced Micro Devices, Inc.
   5 * Author: Andreas Herrmann <herrmann.der.user@googlemail.com>
   6 *
   7 *
   8 * This driver is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License; either
  10 * version 2 of the License, or (at your option) any later version.
  11 *
  12 * This driver is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  15 * See the GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this driver; if not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21#include <linux/err.h>
  22#include <linux/hwmon.h>
  23#include <linux/hwmon-sysfs.h>
  24#include <linux/init.h>
  25#include <linux/module.h>
  26#include <linux/pci.h>
  27#include <linux/bitops.h>
  28#include <asm/processor.h>
  29
  30MODULE_DESCRIPTION("AMD Family 15h CPU processor power monitor");
  31MODULE_AUTHOR("Andreas Herrmann <herrmann.der.user@googlemail.com>");
  32MODULE_LICENSE("GPL");
  33
  34/* Family 16h Northbridge's function 4 PCI ID */
  35#define PCI_DEVICE_ID_AMD_16H_NB_F4     0x1534
  36
  37/* D18F3 */
  38#define REG_NORTHBRIDGE_CAP             0xe8
  39
  40/* D18F4 */
  41#define REG_PROCESSOR_TDP               0x1b8
  42
  43/* D18F5 */
  44#define REG_TDP_RUNNING_AVERAGE         0xe0
  45#define REG_TDP_LIMIT3                  0xe8
  46
  47struct fam15h_power_data {
  48        struct device *hwmon_dev;
  49        unsigned int tdp_to_watts;
  50        unsigned int base_tdp;
  51        unsigned int processor_pwr_watts;
  52};
  53
  54static ssize_t show_power(struct device *dev,
  55                          struct device_attribute *attr, char *buf)
  56{
  57        u32 val, tdp_limit, running_avg_range;
  58        s32 running_avg_capture;
  59        u64 curr_pwr_watts;
  60        struct pci_dev *f4 = to_pci_dev(dev);
  61        struct fam15h_power_data *data = dev_get_drvdata(dev);
  62
  63        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
  64                                  REG_TDP_RUNNING_AVERAGE, &val);
  65        running_avg_capture = (val >> 4) & 0x3fffff;
  66        running_avg_capture = sign_extend32(running_avg_capture, 21);
  67        running_avg_range = (val & 0xf) + 1;
  68
  69        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
  70                                  REG_TDP_LIMIT3, &val);
  71
  72        tdp_limit = val >> 16;
  73        curr_pwr_watts = ((u64)(tdp_limit +
  74                                data->base_tdp)) << running_avg_range;
  75        curr_pwr_watts -= running_avg_capture;
  76        curr_pwr_watts *= data->tdp_to_watts;
  77
  78        /*
  79         * Convert to microWatt
  80         *
  81         * power is in Watt provided as fixed point integer with
  82         * scaling factor 1/(2^16).  For conversion we use
  83         * (10^6)/(2^16) = 15625/(2^10)
  84         */
  85        curr_pwr_watts = (curr_pwr_watts * 15625) >> (10 + running_avg_range);
  86        return sprintf(buf, "%u\n", (unsigned int) curr_pwr_watts);
  87}
  88static DEVICE_ATTR(power1_input, S_IRUGO, show_power, NULL);
  89
  90static ssize_t show_power_crit(struct device *dev,
  91                               struct device_attribute *attr, char *buf)
  92{
  93        struct fam15h_power_data *data = dev_get_drvdata(dev);
  94
  95        return sprintf(buf, "%u\n", data->processor_pwr_watts);
  96}
  97static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, NULL);
  98
  99static ssize_t show_name(struct device *dev,
 100                         struct device_attribute *attr, char *buf)
 101{
 102        return sprintf(buf, "fam15h_power\n");
 103}
 104static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 105
 106static struct attribute *fam15h_power_attrs[] = {
 107        &dev_attr_power1_input.attr,
 108        &dev_attr_power1_crit.attr,
 109        &dev_attr_name.attr,
 110        NULL
 111};
 112
 113static const struct attribute_group fam15h_power_attr_group = {
 114        .attrs  = fam15h_power_attrs,
 115};
 116
 117static bool fam15h_power_is_internal_node0(struct pci_dev *f4)
 118{
 119        u32 val;
 120
 121        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 3),
 122                                  REG_NORTHBRIDGE_CAP, &val);
 123        if ((val & BIT(29)) && ((val >> 30) & 3))
 124                return false;
 125
 126        return true;
 127}
 128
 129/*
 130 * Newer BKDG versions have an updated recommendation on how to properly
 131 * initialize the running average range (was: 0xE, now: 0x9). This avoids
 132 * counter saturations resulting in bogus power readings.
 133 * We correct this value ourselves to cope with older BIOSes.
 134 */
 135static const struct pci_device_id affected_device[] = {
 136        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
 137        { 0 }
 138};
 139
 140static void tweak_runavg_range(struct pci_dev *pdev)
 141{
 142        u32 val;
 143
 144        /*
 145         * let this quirk apply only to the current version of the
 146         * northbridge, since future versions may change the behavior
 147         */
 148        if (!pci_match_id(affected_device, pdev))
 149                return;
 150
 151        pci_bus_read_config_dword(pdev->bus,
 152                PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
 153                REG_TDP_RUNNING_AVERAGE, &val);
 154        if ((val & 0xf) != 0xe)
 155                return;
 156
 157        val &= ~0xf;
 158        val |=  0x9;
 159        pci_bus_write_config_dword(pdev->bus,
 160                PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
 161                REG_TDP_RUNNING_AVERAGE, val);
 162}
 163
 164#ifdef CONFIG_PM
 165static int fam15h_power_resume(struct pci_dev *pdev)
 166{
 167        tweak_runavg_range(pdev);
 168        return 0;
 169}
 170#else
 171#define fam15h_power_resume NULL
 172#endif
 173
 174static void fam15h_power_init_data(struct pci_dev *f4,
 175                                             struct fam15h_power_data *data)
 176{
 177        u32 val;
 178        u64 tmp;
 179
 180        pci_read_config_dword(f4, REG_PROCESSOR_TDP, &val);
 181        data->base_tdp = val >> 16;
 182        tmp = val & 0xffff;
 183
 184        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
 185                                  REG_TDP_LIMIT3, &val);
 186
 187        data->tdp_to_watts = ((val & 0x3ff) << 6) | ((val >> 10) & 0x3f);
 188        tmp *= data->tdp_to_watts;
 189
 190        /* result not allowed to be >= 256W */
 191        if ((tmp >> 16) >= 256)
 192                dev_warn(&f4->dev,
 193                         "Bogus value for ProcessorPwrWatts (processor_pwr_watts>=%u)\n",
 194                         (unsigned int) (tmp >> 16));
 195
 196        /* convert to microWatt */
 197        data->processor_pwr_watts = (tmp * 15625) >> 10;
 198}
 199
 200static int fam15h_power_probe(struct pci_dev *pdev,
 201                                        const struct pci_device_id *id)
 202{
 203        struct fam15h_power_data *data;
 204        struct device *dev = &pdev->dev;
 205        int err;
 206
 207        /*
 208         * though we ignore every other northbridge, we still have to
 209         * do the tweaking on _each_ node in MCM processors as the counters
 210         * are working hand-in-hand
 211         */
 212        tweak_runavg_range(pdev);
 213
 214        if (!fam15h_power_is_internal_node0(pdev))
 215                return -ENODEV;
 216
 217        data = devm_kzalloc(dev, sizeof(struct fam15h_power_data), GFP_KERNEL);
 218        if (!data)
 219                return -ENOMEM;
 220
 221        fam15h_power_init_data(pdev, data);
 222
 223        dev_set_drvdata(dev, data);
 224        err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
 225        if (err)
 226                return err;
 227
 228        data->hwmon_dev = hwmon_device_register(dev);
 229        if (IS_ERR(data->hwmon_dev)) {
 230                err = PTR_ERR(data->hwmon_dev);
 231                goto exit_remove_group;
 232        }
 233
 234        return 0;
 235
 236exit_remove_group:
 237        sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
 238        return err;
 239}
 240
 241static void fam15h_power_remove(struct pci_dev *pdev)
 242{
 243        struct device *dev;
 244        struct fam15h_power_data *data;
 245
 246        dev = &pdev->dev;
 247        data = dev_get_drvdata(dev);
 248        hwmon_device_unregister(data->hwmon_dev);
 249        sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
 250}
 251
 252static DEFINE_PCI_DEVICE_TABLE(fam15h_power_id_table) = {
 253        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
 254        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
 255        {}
 256};
 257MODULE_DEVICE_TABLE(pci, fam15h_power_id_table);
 258
 259static struct pci_driver fam15h_power_driver = {
 260        .name = "fam15h_power",
 261        .id_table = fam15h_power_id_table,
 262        .probe = fam15h_power_probe,
 263        .remove = fam15h_power_remove,
 264        .resume = fam15h_power_resume,
 265};
 266
 267module_pci_driver(fam15h_power_driver);
 268
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