/*
 * k10temp.c - AMD Family 10h/11h/12h/14h/15h/16h processor hardware monitoring
 *
 * Copyright (c) 2009 Clemens Ladisch <clemens@ladisch.de>
 *
 *
 * 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 <asm/processor.h>

MODULE_DESCRIPTION("AMD Family 10h+ CPU core temperature monitor");
MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
MODULE_LICENSE("GPL");

static bool force;
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "force loading on processors with erratum 319");

/* CPUID function 0x80000001, ebx */
#define CPUID_PKGTYPE_MASK      0xf0000000
#define CPUID_PKGTYPE_F         0x00000000
#define CPUID_PKGTYPE_AM2R2_AM3 0x10000000

/* DRAM controller (PCI function 2) */
#define REG_DCT0_CONFIG_HIGH            0x094
#define  DDR3_MODE                      0x00000100

/* miscellaneous (PCI function 3) */
#define REG_HARDWARE_THERMAL_CONTROL    0x64
#define  HTC_ENABLE                     0x00000001

#define REG_REPORTED_TEMPERATURE        0xa4

#define REG_NORTHBRIDGE_CAPABILITIES    0xe8
#define  NB_CAP_HTC                     0x00000400

static ssize_t show_temp(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        u32 regval;

        pci_read_config_dword(to_pci_dev(dev),
                              REG_REPORTED_TEMPERATURE, &regval);
        return sprintf(buf, "%u\n", (regval >> 21) * 125);
}

static ssize_t show_temp_max(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", 70 * 1000);
}

static ssize_t show_temp_crit(struct device *dev,
                              struct device_attribute *devattr, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        int show_hyst = attr->index;
        u32 regval;
        int value;

        pci_read_config_dword(to_pci_dev(dev),
                              REG_HARDWARE_THERMAL_CONTROL, &regval);
        value = ((regval >> 16) & 0x7f) * 500 + 52000;
        if (show_hyst)
                value -= ((regval >> 24) & 0xf) * 500;
        return sprintf(buf, "%d\n", value);
}

static ssize_t show_name(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "k10temp\n");
}

static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
static DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_max, NULL);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp_crit, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IRUGO, show_temp_crit, NULL, 1);
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static bool has_erratum_319(struct pci_dev *pdev)
{
        u32 pkg_type, reg_dram_cfg;

        if (boot_cpu_data.x86 != 0x10)
                return false;

        /*
         * Erratum 319: The thermal sensor of Socket F/AM2+ processors
         *              may be unreliable.
         */
        pkg_type = cpuid_ebx(0x80000001) & CPUID_PKGTYPE_MASK;
        if (pkg_type == CPUID_PKGTYPE_F)
                return true;
        if (pkg_type != CPUID_PKGTYPE_AM2R2_AM3)
                return false;

        /* DDR3 memory implies socket AM3, which is good */
        pci_bus_read_config_dword(pdev->bus,
                                  PCI_DEVFN(PCI_SLOT(pdev->devfn), 2),
                                  REG_DCT0_CONFIG_HIGH, &reg_dram_cfg);
        if (reg_dram_cfg & DDR3_MODE)
                return false;

        /*
         * Unfortunately it is possible to run a socket AM3 CPU with DDR2
         * memory. We blacklist all the cores which do exist in socket AM2+
         * format. It still isn't perfect, as RB-C2 cores exist in both AM2+
         * and AM3 formats, but that's the best we can do.
         */
        return boot_cpu_data.x86_model < 4 ||
               (boot_cpu_data.x86_model == 4 && boot_cpu_data.x86_mask <= 2);
}

static int k10temp_probe(struct pci_dev *pdev,
                                   const struct pci_device_id *id)
{
        struct device *hwmon_dev;
        u32 reg_caps, reg_htc;
        int unreliable = has_erratum_319(pdev);
        int err;

        if (unreliable && !force) {
                dev_err(&pdev->dev,
                        "unreliable CPU thermal sensor; monitoring disabled\n");
                err = -ENODEV;
                goto exit;
        }

        err = device_create_file(&pdev->dev, &dev_attr_temp1_input);
        if (err)
                goto exit;
        err = device_create_file(&pdev->dev, &dev_attr_temp1_max);
        if (err)
                goto exit_remove;

        pci_read_config_dword(pdev, REG_NORTHBRIDGE_CAPABILITIES, &reg_caps);
        pci_read_config_dword(pdev, REG_HARDWARE_THERMAL_CONTROL, &reg_htc);
        if ((reg_caps & NB_CAP_HTC) && (reg_htc & HTC_ENABLE)) {
                err = device_create_file(&pdev->dev,
                                &sensor_dev_attr_temp1_crit.dev_attr);
                if (err)
                        goto exit_remove;
                err = device_create_file(&pdev->dev,
                                &sensor_dev_attr_temp1_crit_hyst.dev_attr);
                if (err)
                        goto exit_remove;
        }

        err = device_create_file(&pdev->dev, &dev_attr_name);
        if (err)
                goto exit_remove;

        hwmon_dev = hwmon_device_register(&pdev->dev);
        if (IS_ERR(hwmon_dev)) {
                err = PTR_ERR(hwmon_dev);
                goto exit_remove;
        }
        pci_set_drvdata(pdev, hwmon_dev);

        if (unreliable && force)
                dev_warn(&pdev->dev,
                         "unreliable CPU thermal sensor; check erratum 319\n");
        return 0;

exit_remove:
        device_remove_file(&pdev->dev, &dev_attr_name);
        device_remove_file(&pdev->dev, &dev_attr_temp1_input);
        device_remove_file(&pdev->dev, &dev_attr_temp1_max);
        device_remove_file(&pdev->dev,
                           &sensor_dev_attr_temp1_crit.dev_attr);
        device_remove_file(&pdev->dev,
                           &sensor_dev_attr_temp1_crit_hyst.dev_attr);
exit:
        return err;
}

static void k10temp_remove(struct pci_dev *pdev)
{
        hwmon_device_unregister(pci_get_drvdata(pdev));
        device_remove_file(&pdev->dev, &dev_attr_name);
        device_remove_file(&pdev->dev, &dev_attr_temp1_input);
        device_remove_file(&pdev->dev, &dev_attr_temp1_max);
        device_remove_file(&pdev->dev,
                           &sensor_dev_attr_temp1_crit.dev_attr);
        device_remove_file(&pdev->dev,
                           &sensor_dev_attr_temp1_crit_hyst.dev_attr);
}

static DEFINE_PCI_DEVICE_TABLE(k10temp_id_table) = {
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_11H_NB_MISC) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F3) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_M10H_F3) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
        {}
};
MODULE_DEVICE_TABLE(pci, k10temp_id_table);

static struct pci_driver k10temp_driver = {
        .name = "k10temp",
        .id_table = k10temp_id_table,
        .probe = k10temp_probe,
        .remove = k10temp_remove,
};

module_pci_driver(k10temp_driver);