/*
 * fam15h_power.c - AMD Family 15h processor power monitoring
 *
 * Copyright (c) 2011 Advanced Micro Devices, Inc.
 * Author: Andreas Herrmann <herrmann.der.user@googlemail.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>
#include <asm/msr.h>

MODULE_DESCRIPTION("AMD Family 15h CPU processor power monitor");
MODULE_AUTHOR("Andreas Herrmann <herrmann.der.user@googlemail.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

#define FAM15H_MIN_NUM_ATTRS            2
#define FAM15H_NUM_GROUPS               2

#define MSR_F15H_CU_MAX_PWR_ACCUMULATOR 0xc001007b

#define PCI_DEVICE_ID_AMD_15H_M70H_NB_F4 0x15b4

struct fam15h_power_data {
        struct pci_dev *pdev;
        unsigned int tdp_to_watts;
        unsigned int base_tdp;
        unsigned int processor_pwr_watts;
        unsigned int cpu_pwr_sample_ratio;
        const struct attribute_group *groups[FAM15H_NUM_GROUPS];
        struct attribute_group group;
        /* maximum accumulated power of a compute unit */
        u64 max_cu_acc_power;
};

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 fam15h_power_data *data = dev_get_drvdata(dev);
        struct pci_dev *f4 = data->pdev;

        pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
                                  REG_TDP_RUNNING_AVERAGE, &val);

        /*
         * On Carrizo and later platforms, TdpRunAvgAccCap bit field
         * is extended to 4:31 from 4:25.
         */
        if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model >= 0x60) {
                running_avg_capture = val >> 4;
                running_avg_capture = sign_extend32(running_avg_capture, 27);
        } else {
                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);

        /*
         * On Carrizo and later platforms, ApmTdpLimit bit field
         * is extended to 16:31 from 16:28.
         */
        if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model >= 0x60)
                tdp_limit = val >> 16;
        else
                tdp_limit = (val >> 16) & 0x1fff;

        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 int fam15h_power_init_attrs(struct pci_dev *pdev,
                                   struct fam15h_power_data *data)
{
        int n = FAM15H_MIN_NUM_ATTRS;
        struct attribute **fam15h_power_attrs;
        struct cpuinfo_x86 *c = &boot_cpu_data;

        if (c->x86 == 0x15 &&
            (c->x86_model <= 0xf ||
             (c->x86_model >= 0x60 && c->x86_model <= 0x7f)))
                n += 1;

        fam15h_power_attrs = devm_kcalloc(&pdev->dev, n,
                                          sizeof(*fam15h_power_attrs),
                                          GFP_KERNEL);

        if (!fam15h_power_attrs)
                return -ENOMEM;

        n = 0;
        fam15h_power_attrs[n++] = &dev_attr_power1_crit.attr;
        if (c->x86 == 0x15 &&
            (c->x86_model <= 0xf ||
             (c->x86_model >= 0x60 && c->x86_model <= 0x7f)))
                fam15h_power_attrs[n++] = &dev_attr_power1_input.attr;

        data->group.attrs = fam15h_power_attrs;

        return 0;
}

static bool should_load_on_this_node(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 int fam15h_power_init_data(struct pci_dev *f4,
                                  struct fam15h_power_data *data)
{
        u32 val, eax, ebx, ecx, edx;
        u64 tmp;
        int ret;

        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;

        ret = fam15h_power_init_attrs(f4, data);
        if (ret)
                return ret;

        cpuid(0x80000007, &eax, &ebx, &ecx, &edx);

        /* CPUID Fn8000_0007:EDX[12] indicates to support accumulated power */
        if (!(edx & BIT(12)))
                return 0;

        /*
         * determine the ratio of the compute unit power accumulator
         * sample period to the PTSC counter period by executing CPUID
         * Fn8000_0007:ECX
         */
        data->cpu_pwr_sample_ratio = ecx;

        if (rdmsrl_safe(MSR_F15H_CU_MAX_PWR_ACCUMULATOR, &tmp)) {
                pr_err("Failed to read max compute unit power accumulator MSR\n");
                return -ENODEV;
        }

        data->max_cu_acc_power = tmp;

        return 0;
}

static int fam15h_power_probe(struct pci_dev *pdev,
                              const struct pci_device_id *id)
{
        struct fam15h_power_data *data;
        struct device *dev = &pdev->dev;
        struct device *hwmon_dev;
        int ret;

        /*
         * 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 (!should_load_on_this_node(pdev))
                return -ENODEV;

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

        ret = fam15h_power_init_data(pdev, data);
        if (ret)
                return ret;

        data->pdev = pdev;

        data->groups[0] = &data->group;

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, "fam15h_power",
                                                           data,
                                                           &data->groups[0]);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct pci_device_id fam15h_power_id_table[] = {
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_M70H_NB_F4) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_16H_M30H_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,
        .resume = fam15h_power_resume,
};

module_pci_driver(fam15h_power_driver);