fam15h_power.c

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/*
 * fam15h_power.c - AMD Family 15h processor power monitoring
 *
 * Copyright (c) 2011 Advanced Micro Devices, Inc.
 * Author: Andreas Herrmann <[email protected]>
 *
 *
 * 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 <[email protected]>");
MODULE_LICENSE("GPL");

/* Family 16h Northbridge's function 4 PCI ID */
#define PCI_DEVICE_ID_AMD_16H_NB_F4 0x1534

/* 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, 21);
    running_avg_range = (val & 0xf) + 1;

    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 = ((u64)(tdp_limit +
                data->base_tdp)) << running_avg_range;
    curr_pwr_watts -= running_avg_capture;
    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 + running_avg_range);
    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;
}

/*
 * Newer BKDG versions have an updated recommendation on how to properly
 * initialize the running average range (was: 0xE, now: 0x9). This avoids
 * counter saturations resulting in bogus power readings.
 * We correct this value ourselves to cope with older BIOSes.
 */
static const struct pci_device_id affected_device[] = {
    { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
    { 0 }
};

static void tweak_runavg_range(struct pci_dev *pdev)
{
    u32 val;

    /*
     * let this quirk apply only to the current version of the
     * northbridge, since future versions may change the behavior
     */
    if (!pci_match_id(affected_device, pdev))
        return;

    pci_bus_read_config_dword(pdev->bus,
        PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
        REG_TDP_RUNNING_AVERAGE, &val);
    if ((val & 0xf) != 0xe)
        return;

    val &= ~0xf;
    val |=  0x9;
    pci_bus_write_config_dword(pdev->bus,
        PCI_DEVFN(PCI_SLOT(pdev->devfn), 5),
        REG_TDP_RUNNING_AVERAGE, val);
}

#ifdef CONFIG_PM
static int fam15h_power_resume(struct pci_dev *pdev)
{
    tweak_runavg_range(pdev);
    return 0;
}
#else
#define fam15h_power_resume NULL
#endif

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 = &pdev->dev;
    int err;

    /*
     * though we ignore every other northbridge, we still have to
     * do the tweaking on _each_ node in MCM processors as the counters
     * are working hand-in-hand
     */
    tweak_runavg_range(pdev);

    if (!fam15h_power_is_internal_node0(pdev))
        return -ENODEV;

    data = devm_kzalloc(dev, sizeof(struct fam15h_power_data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    fam15h_power_init_data(pdev, data);

    dev_set_drvdata(dev, data);
    err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
    if (err)
        return err;

    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);
    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);
}

static DEFINE_PCI_DEVICE_TABLE(fam15h_power_id_table) = {
    { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
    { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_16H_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),
    .resume = fam15h_power_resume,
};

module_pci_driver(fam15h_power_driver);