// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * A hwmon driver for the Intel 5000 series chipset FB-DIMM AMB
 * temperature sensors
 * Copyright (C) 2007 IBM
 *
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */

#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/log2.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define DRVNAME "i5k_amb"

#define I5K_REG_AMB_BASE_ADDR           0x48
#define I5K_REG_AMB_LEN_ADDR            0x50
#define I5K_REG_CHAN0_PRESENCE_ADDR     0x64
#define I5K_REG_CHAN1_PRESENCE_ADDR     0x66

#define AMB_REG_TEMP_MIN_ADDR           0x80
#define AMB_REG_TEMP_MID_ADDR           0x81
#define AMB_REG_TEMP_MAX_ADDR           0x82
#define AMB_REG_TEMP_STATUS_ADDR        0x84
#define AMB_REG_TEMP_ADDR               0x85

#define AMB_CONFIG_SIZE                 2048
#define AMB_FUNC_3_OFFSET               768

static unsigned long amb_reg_temp_status(unsigned int amb)
{
        return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_STATUS_ADDR +
               AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_min(unsigned int amb)
{
        return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MIN_ADDR +
               AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_mid(unsigned int amb)
{
        return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MID_ADDR +
               AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp_max(unsigned int amb)
{
        return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_MAX_ADDR +
               AMB_CONFIG_SIZE * amb;
}

static unsigned long amb_reg_temp(unsigned int amb)
{
        return AMB_FUNC_3_OFFSET + AMB_REG_TEMP_ADDR +
               AMB_CONFIG_SIZE * amb;
}

#define MAX_MEM_CHANNELS                4
#define MAX_AMBS_PER_CHANNEL            16
#define MAX_AMBS                        (MAX_MEM_CHANNELS * \
                                         MAX_AMBS_PER_CHANNEL)
#define CHANNEL_SHIFT                   4
#define DIMM_MASK                       0xF
/*
 * Ugly hack: For some reason the highest bit is set if there
 * are _any_ DIMMs in the channel.  Attempting to read from
 * this "high-order" AMB results in a memory bus error, so
 * for now we'll just ignore that top bit, even though that
 * might prevent us from seeing the 16th DIMM in the channel.
 */
#define REAL_MAX_AMBS_PER_CHANNEL       15
#define KNOBS_PER_AMB                   6

static unsigned long amb_num_from_reg(unsigned int byte_num, unsigned int bit)
{
        return byte_num * MAX_AMBS_PER_CHANNEL + bit;
}

#define AMB_SYSFS_NAME_LEN              16
struct i5k_device_attribute {
        struct sensor_device_attribute s_attr;
        char name[AMB_SYSFS_NAME_LEN];
};

struct i5k_amb_data {
        struct device *hwmon_dev;

        unsigned long amb_base;
        unsigned long amb_len;
        u16 amb_present[MAX_MEM_CHANNELS];
        void __iomem *amb_mmio;
        struct i5k_device_attribute *attrs;
        unsigned int num_attrs;
};

static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);

static struct platform_device *amb_pdev;

static u8 amb_read_byte(struct i5k_amb_data *data, unsigned long offset)
{
        return ioread8(data->amb_mmio + offset);
}

static void amb_write_byte(struct i5k_amb_data *data, unsigned long offset,
                           u8 val)
{
        iowrite8(val, data->amb_mmio + offset);
}

static ssize_t show_amb_alarm(struct device *dev,
                             struct device_attribute *devattr,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);

        if (!(amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x20) &&
             (amb_read_byte(data, amb_reg_temp_status(attr->index)) & 0x8))
                return sprintf(buf, "1\n");
        else
                return sprintf(buf, "0\n");
}

static ssize_t store_amb_min(struct device *dev,
                             struct device_attribute *devattr,
                             const char *buf,
                             size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        unsigned long temp;
        int ret = kstrtoul(buf, 10, &temp);
        if (ret < 0)
                return ret;

        temp = temp / 500;
        if (temp > 255)
                temp = 255;

        amb_write_byte(data, amb_reg_temp_min(attr->index), temp);
        return count;
}

static ssize_t store_amb_mid(struct device *dev,
                             struct device_attribute *devattr,
                             const char *buf,
                             size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        unsigned long temp;
        int ret = kstrtoul(buf, 10, &temp);
        if (ret < 0)
                return ret;

        temp = temp / 500;
        if (temp > 255)
                temp = 255;

        amb_write_byte(data, amb_reg_temp_mid(attr->index), temp);
        return count;
}

static ssize_t store_amb_max(struct device *dev,
                             struct device_attribute *devattr,
                             const char *buf,
                             size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        unsigned long temp;
        int ret = kstrtoul(buf, 10, &temp);
        if (ret < 0)
                return ret;

        temp = temp / 500;
        if (temp > 255)
                temp = 255;

        amb_write_byte(data, amb_reg_temp_max(attr->index), temp);
        return count;
}

static ssize_t show_amb_min(struct device *dev,
                             struct device_attribute *devattr,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n",
                500 * amb_read_byte(data, amb_reg_temp_min(attr->index)));
}

static ssize_t show_amb_mid(struct device *dev,
                             struct device_attribute *devattr,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n",
                500 * amb_read_byte(data, amb_reg_temp_mid(attr->index)));
}

static ssize_t show_amb_max(struct device *dev,
                             struct device_attribute *devattr,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n",
                500 * amb_read_byte(data, amb_reg_temp_max(attr->index)));
}

static ssize_t show_amb_temp(struct device *dev,
                             struct device_attribute *devattr,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct i5k_amb_data *data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n",
                500 * amb_read_byte(data, amb_reg_temp(attr->index)));
}

static ssize_t show_label(struct device *dev,
                          struct device_attribute *devattr,
                          char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);

        return sprintf(buf, "Ch. %d DIMM %d\n", attr->index >> CHANNEL_SHIFT,
                       attr->index & DIMM_MASK);
}

static int i5k_amb_hwmon_init(struct platform_device *pdev)
{
        int i, j, k, d = 0;
        u16 c;
        int res = 0;
        int num_ambs = 0;
        struct i5k_amb_data *data = platform_get_drvdata(pdev);

        /* Count the number of AMBs found */
        /* ignore the high-order bit, see "Ugly hack" comment above */
        for (i = 0; i < MAX_MEM_CHANNELS; i++)
                num_ambs += hweight16(data->amb_present[i] & 0x7fff);

        /* Set up sysfs stuff */
        data->attrs = kzalloc(array3_size(num_ambs, KNOBS_PER_AMB,
                                          sizeof(*data->attrs)),
                              GFP_KERNEL);
        if (!data->attrs)
                return -ENOMEM;
        data->num_attrs = 0;

        for (i = 0; i < MAX_MEM_CHANNELS; i++) {
                c = data->amb_present[i];
                for (j = 0; j < REAL_MAX_AMBS_PER_CHANNEL; j++, c >>= 1) {
                        struct i5k_device_attribute *iattr;

                        k = amb_num_from_reg(i, j);
                        if (!(c & 0x1))
                                continue;
                        d++;

                        /* sysfs label */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_label", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0444;
                        iattr->s_attr.dev_attr.show = show_label;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;

                        /* Temperature sysfs knob */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_input", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0444;
                        iattr->s_attr.dev_attr.show = show_amb_temp;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;

                        /* Temperature min sysfs knob */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_min", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0644;
                        iattr->s_attr.dev_attr.show = show_amb_min;
                        iattr->s_attr.dev_attr.store = store_amb_min;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;

                        /* Temperature mid sysfs knob */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_mid", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0644;
                        iattr->s_attr.dev_attr.show = show_amb_mid;
                        iattr->s_attr.dev_attr.store = store_amb_mid;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;

                        /* Temperature max sysfs knob */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_max", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0644;
                        iattr->s_attr.dev_attr.show = show_amb_max;
                        iattr->s_attr.dev_attr.store = store_amb_max;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;

                        /* Temperature alarm sysfs knob */
                        iattr = data->attrs + data->num_attrs;
                        snprintf(iattr->name, AMB_SYSFS_NAME_LEN,
                                 "temp%d_alarm", d);
                        iattr->s_attr.dev_attr.attr.name = iattr->name;
                        iattr->s_attr.dev_attr.attr.mode = 0444;
                        iattr->s_attr.dev_attr.show = show_amb_alarm;
                        iattr->s_attr.index = k;
                        sysfs_attr_init(&iattr->s_attr.dev_attr.attr);
                        res = device_create_file(&pdev->dev,
                                                 &iattr->s_attr.dev_attr);
                        if (res)
                                goto exit_remove;
                        data->num_attrs++;
                }
        }

        res = device_create_file(&pdev->dev, &dev_attr_name.attr);
        if (res)
                goto exit_remove;

        data->hwmon_dev = hwmon_device_register(&pdev->dev);
        if (IS_ERR(data->hwmon_dev)) {
                res = PTR_ERR(data->hwmon_dev);
                goto exit_remove;
        }

        return res;

exit_remove:
        device_remove_file(&pdev->dev, &dev_attr_name.attr);
        for (i = 0; i < data->num_attrs; i++)
                device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
        kfree(data->attrs);

        return res;
}

static int i5k_amb_add(void)
{
        int res;

        /* only ever going to be one of these */
        amb_pdev = platform_device_alloc(DRVNAME, 0);
        if (!amb_pdev)
                return -ENOMEM;

        res = platform_device_add(amb_pdev);
        if (res)
                goto err;
        return 0;

err:
        platform_device_put(amb_pdev);
        return res;
}

static int i5k_find_amb_registers(struct i5k_amb_data *data,
                                            unsigned long devid)
{
        struct pci_dev *pcidev;
        u32 val32;
        int res = -ENODEV;

        /* Find AMB register memory space */
        pcidev = pci_get_device(PCI_VENDOR_ID_INTEL,
                                devid,
                                NULL);
        if (!pcidev)
                return -ENODEV;

        pci_read_config_dword(pcidev, I5K_REG_AMB_BASE_ADDR, &val32);
        if (val32 == (u32)~0)
                goto out;
        data->amb_base = val32;

        pci_read_config_dword(pcidev, I5K_REG_AMB_LEN_ADDR, &val32);
        if (val32 == (u32)~0)
                goto out;
        data->amb_len = val32;

        /* Is it big enough? */
        if (data->amb_len < AMB_CONFIG_SIZE * MAX_AMBS) {
                dev_err(&pcidev->dev, "AMB region too small!\n");
                goto out;
        }

        res = 0;
out:
        pci_dev_put(pcidev);
        return res;
}

static int i5k_channel_probe(u16 *amb_present, unsigned long dev_id)
{
        struct pci_dev *pcidev;
        u16 val16;
        int res = -ENODEV;

        /* Copy the DIMM presence map for these two channels */
        pcidev = pci_get_device(PCI_VENDOR_ID_INTEL, dev_id, NULL);
        if (!pcidev)
                return -ENODEV;

        pci_read_config_word(pcidev, I5K_REG_CHAN0_PRESENCE_ADDR, &val16);
        if (val16 == (u16)~0)
                goto out;
        amb_present[0] = val16;

        pci_read_config_word(pcidev, I5K_REG_CHAN1_PRESENCE_ADDR, &val16);
        if (val16 == (u16)~0)
                goto out;
        amb_present[1] = val16;

        res = 0;

out:
        pci_dev_put(pcidev);
        return res;
}

static struct {
        unsigned long err;
        unsigned long fbd0;
} chipset_ids[]  = {
        { PCI_DEVICE_ID_INTEL_5000_ERR, PCI_DEVICE_ID_INTEL_5000_FBD0 },
        { PCI_DEVICE_ID_INTEL_5400_ERR, PCI_DEVICE_ID_INTEL_5400_FBD0 },
        { 0, 0 }
};

#ifdef MODULE
static const struct pci_device_id i5k_amb_ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5400_ERR) },
        { 0, }
};
MODULE_DEVICE_TABLE(pci, i5k_amb_ids);
#endif

static int i5k_amb_probe(struct platform_device *pdev)
{
        struct i5k_amb_data *data;
        struct resource *reso;
        int i, res;

        data = kzalloc_obj(*data);
        if (!data)
                return -ENOMEM;

        /* Figure out where the AMB registers live */
        i = 0;
        do {
                res = i5k_find_amb_registers(data, chipset_ids[i].err);
                if (res == 0)
                        break;
                i++;
        } while (chipset_ids[i].err);

        if (res)
                goto err;

        /* Copy the DIMM presence map for the first two channels */
        res = i5k_channel_probe(&data->amb_present[0], chipset_ids[i].fbd0);
        if (res)
                goto err;

        /* Copy the DIMM presence map for the optional second two channels */
        i5k_channel_probe(&data->amb_present[2], chipset_ids[i].fbd0 + 1);

        /* Set up resource regions */
        reso = request_mem_region(data->amb_base, data->amb_len, DRVNAME);
        if (!reso) {
                res = -EBUSY;
                goto err;
        }

        data->amb_mmio = ioremap(data->amb_base, data->amb_len);
        if (!data->amb_mmio) {
                res = -EBUSY;
                goto err_map_failed;
        }

        platform_set_drvdata(pdev, data);

        res = i5k_amb_hwmon_init(pdev);
        if (res)
                goto err_init_failed;

        return res;

err_init_failed:
        iounmap(data->amb_mmio);
err_map_failed:
        release_mem_region(data->amb_base, data->amb_len);
err:
        kfree(data);
        return res;
}

static void i5k_amb_remove(struct platform_device *pdev)
{
        int i;
        struct i5k_amb_data *data = platform_get_drvdata(pdev);

        hwmon_device_unregister(data->hwmon_dev);
        device_remove_file(&pdev->dev, &dev_attr_name.attr);
        for (i = 0; i < data->num_attrs; i++)
                device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
        kfree(data->attrs);
        iounmap(data->amb_mmio);
        release_mem_region(data->amb_base, data->amb_len);
        kfree(data);
}

static struct platform_driver i5k_amb_driver = {
        .driver = {
                .name = DRVNAME,
        },
        .probe = i5k_amb_probe,
        .remove = i5k_amb_remove,
};

static int __init i5k_amb_init(void)
{
        int res;

        res = platform_driver_register(&i5k_amb_driver);
        if (res)
                return res;

        res = i5k_amb_add();
        if (res)
                platform_driver_unregister(&i5k_amb_driver);

        return res;
}

static void __exit i5k_amb_exit(void)
{
        platform_device_unregister(amb_pdev);
        platform_driver_unregister(&i5k_amb_driver);
}

MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
MODULE_DESCRIPTION("Intel 5000 chipset FB-DIMM AMB temperature sensor");
MODULE_LICENSE("GPL");

module_init(i5k_amb_init);
module_exit(i5k_amb_exit);