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 <andreas.herrmann3@amd.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 <andreas.herrmann3@amd.com>");
  32MODULE_LICENSE("GPL");
  33
  34/* D18F3 */
  35#define REG_NORTHBRIDGE_CAP             0xe8
  36
  37/* D18F4 */
  38#define REG_PROCESSOR_TDP               0x1b8
  39
  40/* D18F5 */
  41#define REG_TDP_RUNNING_AVERAGE         0xe0
  42#define REG_TDP_LIMIT3                  0xe8
  43
  44struct fam15h_power_data {
  45        struct device *hwmon_dev;
  46        unsigned int tdp_to_watts;
  47        unsigned int base_tdp;
  48        unsigned int processor_pwr_watts;
  49};
  50
  51static ssize_t show_power(struct device *dev,
  52                          struct device_attribute *attr, char *buf)
  53{
  54        u32 val, tdp_limit, running_avg_range;
  55        s32 running_avg_capture;
  56        u64 curr_pwr_watts;
  57        struct pci_dev *f4 = to_pci_dev(dev);
  58        struct fam15h_power_data *data = dev_get_drvdata(dev);
  59
  60        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
  61                                  REG_TDP_RUNNING_AVERAGE, &val);
  62        running_avg_capture = (val >> 4) & 0x3fffff;
  63        running_avg_capture = sign_extend32(running_avg_capture, 21);
  64        running_avg_range = (val & 0xf) + 1;
  65
  66        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
  67                                  REG_TDP_LIMIT3, &val);
  68
  69        tdp_limit = val >> 16;
  70        curr_pwr_watts = ((u64)(tdp_limit +
  71                                data->base_tdp)) << running_avg_range;
  72        curr_pwr_watts -= running_avg_capture;
  73        curr_pwr_watts *= data->tdp_to_watts;
  74
  75        /*
  76         * Convert to microWatt
  77         *
  78         * power is in Watt provided as fixed point integer with
  79         * scaling factor 1/(2^16).  For conversion we use
  80         * (10^6)/(2^16) = 15625/(2^10)
  81         */
  82        curr_pwr_watts = (curr_pwr_watts * 15625) >> (10 + running_avg_range);
  83        return sprintf(buf, "%u\n", (unsigned int) curr_pwr_watts);
  84}
  85static DEVICE_ATTR(power1_input, S_IRUGO, show_power, NULL);
  86
  87static ssize_t show_power_crit(struct device *dev,
  88                               struct device_attribute *attr, char *buf)
  89{
  90        struct fam15h_power_data *data = dev_get_drvdata(dev);
  91
  92        return sprintf(buf, "%u\n", data->processor_pwr_watts);
  93}
  94static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, NULL);
  95
  96static ssize_t show_name(struct device *dev,
  97                         struct device_attribute *attr, char *buf)
  98{
  99        return sprintf(buf, "fam15h_power\n");
 100}
 101static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 102
 103static struct attribute *fam15h_power_attrs[] = {
 104        &dev_attr_power1_input.attr,
 105        &dev_attr_power1_crit.attr,
 106        &dev_attr_name.attr,
 107        NULL
 108};
 109
 110static const struct attribute_group fam15h_power_attr_group = {
 111        .attrs  = fam15h_power_attrs,
 112};
 113
 114static bool __devinit fam15h_power_is_internal_node0(struct pci_dev *f4)
 115{
 116        u32 val;
 117
 118        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 3),
 119                                  REG_NORTHBRIDGE_CAP, &val);
 120        if ((val & BIT(29)) && ((val >> 30) & 3))
 121                return false;
 122
 123        return true;
 124}
 125
 126/*
 127 * Newer BKDG versions have an updated recommendation on how to properly
 128 * initialize the running average range (was: 0xE, now: 0x9). This avoids
 129 * counter saturations resulting in bogus power readings.
 130 * We correct this value ourselves to cope with older BIOSes.
 131 */
 132static const struct pci_device_id affected_device[] = {
 133        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
 134        { 0 }
 135};
 136
 137static void tweak_runavg_range(struct pci_dev *pdev)
 138{
 139        u32 val;
 140
 141        /*
 142         * let this quirk apply only to the current version of the
 143         * northbridge, since future versions may change the behavior
 144         */
 145        if (!pci_match_id(affected_device, pdev))
 146                return;
 147
 148        pci_bus_read_config_dword(pdev->bus,
 149                PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
 150                REG_TDP_RUNNING_AVERAGE, &val);
 151        if ((val & 0xf) != 0xe)
 152                return;
 153
 154        val &= ~0xf;
 155        val |=  0x9;
 156        pci_bus_write_config_dword(pdev->bus,
 157                PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
 158                REG_TDP_RUNNING_AVERAGE, val);
 159}
 160
 161#ifdef CONFIG_PM
 162static int fam15h_power_resume(struct pci_dev *pdev)
 163{
 164        tweak_runavg_range(pdev);
 165        return 0;
 166}
 167#else
 168#define fam15h_power_resume NULL
 169#endif
 170
 171static void __devinit fam15h_power_init_data(struct pci_dev *f4,
 172                                             struct fam15h_power_data *data)
 173{
 174        u32 val;
 175        u64 tmp;
 176
 177        pci_read_config_dword(f4, REG_PROCESSOR_TDP, &val);
 178        data->base_tdp = val >> 16;
 179        tmp = val & 0xffff;
 180
 181        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
 182                                  REG_TDP_LIMIT3, &val);
 183
 184        data->tdp_to_watts = ((val & 0x3ff) << 6) | ((val >> 10) & 0x3f);
 185        tmp *= data->tdp_to_watts;
 186
 187        /* result not allowed to be >= 256W */
 188        if ((tmp >> 16) >= 256)
 189                dev_warn(&f4->dev, "Bogus value for ProcessorPwrWatts "
 190                         "(processor_pwr_watts>=%u)\n",
 191                         (unsigned int) (tmp >> 16));
 192
 193        /* convert to microWatt */
 194        data->processor_pwr_watts = (tmp * 15625) >> 10;
 195}
 196
 197static int __devinit fam15h_power_probe(struct pci_dev *pdev,
 198                                        const struct pci_device_id *id)
 199{
 200        struct fam15h_power_data *data;
 201        struct device *dev;
 202        int err;
 203
 204        /*
 205         * though we ignore every other northbridge, we still have to
 206         * do the tweaking on _each_ node in MCM processors as the counters
 207         * are working hand-in-hand
 208         */
 209        tweak_runavg_range(pdev);
 210
 211        if (!fam15h_power_is_internal_node0(pdev)) {
 212                err = -ENODEV;
 213                goto exit;
 214        }
 215
 216        data = kzalloc(sizeof(struct fam15h_power_data), GFP_KERNEL);
 217        if (!data) {
 218                err = -ENOMEM;
 219                goto exit;
 220        }
 221        fam15h_power_init_data(pdev, data);
 222        dev = &pdev->dev;
 223
 224        dev_set_drvdata(dev, data);
 225        err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
 226        if (err)
 227                goto exit_free_data;
 228
 229        data->hwmon_dev = hwmon_device_register(dev);
 230        if (IS_ERR(data->hwmon_dev)) {
 231                err = PTR_ERR(data->hwmon_dev);
 232                goto exit_remove_group;
 233        }
 234
 235        return 0;
 236
 237exit_remove_group:
 238        sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
 239exit_free_data:
 240        kfree(data);
 241exit:
 242        return err;
 243}
 244
 245static void __devexit fam15h_power_remove(struct pci_dev *pdev)
 246{
 247        struct device *dev;
 248        struct fam15h_power_data *data;
 249
 250        dev = &pdev->dev;
 251        data = dev_get_drvdata(dev);
 252        hwmon_device_unregister(data->hwmon_dev);
 253        sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
 254        dev_set_drvdata(dev, NULL);
 255        kfree(data);
 256}
 257
 258static DEFINE_PCI_DEVICE_TABLE(fam15h_power_id_table) = {
 259        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
 260        {}
 261};
 262MODULE_DEVICE_TABLE(pci, fam15h_power_id_table);
 263
 264static struct pci_driver fam15h_power_driver = {
 265        .name = "fam15h_power",
 266        .id_table = fam15h_power_id_table,
 267        .probe = fam15h_power_probe,
 268        .remove = __devexit_p(fam15h_power_remove),
 269        .resume = fam15h_power_resume,
 270};
 271
 272module_pci_driver(fam15h_power_driver);
 273
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