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

#include <linux/ipmi.h>
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/err.h>

#define REFRESH_INTERVAL        (2 * HZ)
#define DRVNAME                 "ibmpex"

#define PEX_GET_VERSION         1
#define PEX_GET_SENSOR_COUNT    2
#define PEX_GET_SENSOR_NAME     3
#define PEX_RESET_HIGH_LOW      4
#define PEX_GET_SENSOR_DATA     6

#define PEX_NET_FUNCTION        0x3A
#define PEX_COMMAND             0x3C

static inline u16 extract_value(const char *data, int offset)
{
        return be16_to_cpup((__be16 *)&data[offset]);
}

#define TEMP_SENSOR             1
#define POWER_SENSOR            2

#define PEX_SENSOR_TYPE_LEN     3
static u8 const power_sensor_sig[] = {0x70, 0x77, 0x72};
static u8 const temp_sensor_sig[]  = {0x74, 0x65, 0x6D};

#define PEX_MULT_LEN            2
static u8 const watt_sensor_sig[]  = {0x41, 0x43};

#define PEX_NUM_SENSOR_FUNCS    3
static const char * const sensor_name_suffixes[] = {
        "",
        "_lowest",
        "_highest"
};

static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
static void ibmpex_register_bmc(int iface, struct device *dev);
static void ibmpex_bmc_gone(int iface);

struct ibmpex_sensor_data {
        int                     in_use;
        s16                     values[PEX_NUM_SENSOR_FUNCS];
        int                     multiplier;

        struct sensor_device_attribute_2        attr[PEX_NUM_SENSOR_FUNCS];
};

struct ibmpex_bmc_data {
        struct list_head        list;
        struct device           *hwmon_dev;
        struct device           *bmc_device;
        struct mutex            lock;
        bool                    valid;
        unsigned long           last_updated;   /* In jiffies */

        struct ipmi_addr        address;
        struct completion       read_complete;
        struct ipmi_user        *user;
        int                     interface;

        struct kernel_ipmi_msg  tx_message;
        unsigned char           tx_msg_data[IPMI_MAX_MSG_LENGTH];
        long                    tx_msgid;

        unsigned char           rx_msg_data[IPMI_MAX_MSG_LENGTH];
        unsigned long           rx_msg_len;
        unsigned char           rx_result;
        int                     rx_recv_type;

        unsigned char           sensor_major;
        unsigned char           sensor_minor;

        unsigned char           num_sensors;
        struct ibmpex_sensor_data       *sensors;
};

struct ibmpex_driver_data {
        struct list_head        bmc_data;
        struct ipmi_smi_watcher bmc_events;
        struct ipmi_user_hndl   ipmi_hndlrs;
};

static struct ibmpex_driver_data driver_data = {
        .bmc_data = LIST_HEAD_INIT(driver_data.bmc_data),
        .bmc_events = {
                .owner = THIS_MODULE,
                .new_smi = ibmpex_register_bmc,
                .smi_gone = ibmpex_bmc_gone,
        },
        .ipmi_hndlrs = {
                .ipmi_recv_hndl = ibmpex_msg_handler,
        },
};

static int ibmpex_send_message(struct ibmpex_bmc_data *data)
{
        int err;

        err = ipmi_validate_addr(&data->address, sizeof(data->address));
        if (err)
                goto out;

        data->tx_msgid++;
        err = ipmi_request_settime(data->user, &data->address, data->tx_msgid,
                                   &data->tx_message, data, 0, 0, 0);
        if (err)
                goto out1;

        return 0;
out1:
        dev_err(data->bmc_device, "request_settime=%x\n", err);
        return err;
out:
        dev_err(data->bmc_device, "validate_addr=%x\n", err);
        return err;
}

static int ibmpex_ver_check(struct ibmpex_bmc_data *data)
{
        data->tx_msg_data[0] = PEX_GET_VERSION;
        data->tx_message.data_len = 1;
        ibmpex_send_message(data);

        wait_for_completion(&data->read_complete);

        if (data->rx_result || data->rx_msg_len != 6)
                return -ENOENT;

        data->sensor_major = data->rx_msg_data[0];
        data->sensor_minor = data->rx_msg_data[1];

        dev_info(data->bmc_device,
                 "Found BMC with sensor interface v%d.%d %d-%02d-%02d on interface %d\n",
                 data->sensor_major,
                 data->sensor_minor,
                 extract_value(data->rx_msg_data, 2),
                 data->rx_msg_data[4],
                 data->rx_msg_data[5],
                 data->interface);

        return 0;
}

static int ibmpex_query_sensor_count(struct ibmpex_bmc_data *data)
{
        data->tx_msg_data[0] = PEX_GET_SENSOR_COUNT;
        data->tx_message.data_len = 1;
        ibmpex_send_message(data);

        wait_for_completion(&data->read_complete);

        if (data->rx_result || data->rx_msg_len != 1)
                return -ENOENT;

        return data->rx_msg_data[0];
}

static int ibmpex_query_sensor_name(struct ibmpex_bmc_data *data, int sensor)
{
        data->tx_msg_data[0] = PEX_GET_SENSOR_NAME;
        data->tx_msg_data[1] = sensor;
        data->tx_message.data_len = 2;
        ibmpex_send_message(data);

        wait_for_completion(&data->read_complete);

        if (data->rx_result || data->rx_msg_len < 1)
                return -ENOENT;

        return 0;
}

static int ibmpex_query_sensor_data(struct ibmpex_bmc_data *data, int sensor)
{
        data->tx_msg_data[0] = PEX_GET_SENSOR_DATA;
        data->tx_msg_data[1] = sensor;
        data->tx_message.data_len = 2;
        ibmpex_send_message(data);

        wait_for_completion(&data->read_complete);

        if (data->rx_result || data->rx_msg_len < 26) {
                dev_err(data->bmc_device, "Error reading sensor %d.\n",
                        sensor);
                return -ENOENT;
        }

        return 0;
}

static int ibmpex_reset_high_low_data(struct ibmpex_bmc_data *data)
{
        data->tx_msg_data[0] = PEX_RESET_HIGH_LOW;
        data->tx_message.data_len = 1;
        ibmpex_send_message(data);

        wait_for_completion(&data->read_complete);

        return 0;
}

static void ibmpex_update_device(struct ibmpex_bmc_data *data)
{
        int i, err;

        mutex_lock(&data->lock);
        if (time_before(jiffies, data->last_updated + REFRESH_INTERVAL) &&
            data->valid)
                goto out;

        for (i = 0; i < data->num_sensors; i++) {
                if (!data->sensors[i].in_use)
                        continue;
                err = ibmpex_query_sensor_data(data, i);
                if (err)
                        continue;
                data->sensors[i].values[0] =
                        extract_value(data->rx_msg_data, 16);
                data->sensors[i].values[1] =
                        extract_value(data->rx_msg_data, 18);
                data->sensors[i].values[2] =
                        extract_value(data->rx_msg_data, 20);
        }

        data->last_updated = jiffies;
        data->valid = true;

out:
        mutex_unlock(&data->lock);
}

static struct ibmpex_bmc_data *get_bmc_data(int iface)
{
        struct ibmpex_bmc_data *p, *next;

        list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
                if (p->interface == iface)
                        return p;

        return NULL;
}

static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);

static ssize_t ibmpex_show_sensor(struct device *dev,
                                  struct device_attribute *devattr,
                                  char *buf)
{
        struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
        struct ibmpex_bmc_data *data = dev_get_drvdata(dev);
        int mult = data->sensors[attr->index].multiplier;
        ibmpex_update_device(data);

        return sprintf(buf, "%d\n",
                       data->sensors[attr->index].values[attr->nr] * mult);
}

static ssize_t ibmpex_high_low_store(struct device *dev,
                                     struct device_attribute *devattr,
                                     const char *buf, size_t count)
{
        struct ibmpex_bmc_data *data = dev_get_drvdata(dev);

        ibmpex_reset_high_low_data(data);

        return count;
}

static SENSOR_DEVICE_ATTR_WO(reset_high_low, ibmpex_high_low, 0);

static int is_power_sensor(const char *sensor_id, int len)
{
        if (len < PEX_SENSOR_TYPE_LEN)
                return 0;

        if (!memcmp(sensor_id, power_sensor_sig, PEX_SENSOR_TYPE_LEN))
                return 1;
        return 0;
}

static int is_temp_sensor(const char *sensor_id, int len)
{
        if (len < PEX_SENSOR_TYPE_LEN)
                return 0;

        if (!memcmp(sensor_id, temp_sensor_sig, PEX_SENSOR_TYPE_LEN))
                return 1;
        return 0;
}

static int power_sensor_multiplier(struct ibmpex_bmc_data *data,
                                   const char *sensor_id, int len)
{
        int i;

        if (data->sensor_major == 2)
                return 1000000;

        for (i = PEX_SENSOR_TYPE_LEN; i < len - 1; i++)
                if (!memcmp(&sensor_id[i], watt_sensor_sig, PEX_MULT_LEN))
                        return 1000000;

        return 100000;
}

static int create_sensor(struct ibmpex_bmc_data *data, int type,
                         int counter, int sensor, int func)
{
        int err;
        char *n;

        n = kmalloc(32, GFP_KERNEL);
        if (!n)
                return -ENOMEM;

        if (type == TEMP_SENSOR)
                sprintf(n, "temp%d_input%s",
                        counter, sensor_name_suffixes[func]);
        else if (type == POWER_SENSOR)
                sprintf(n, "power%d_average%s",
                        counter, sensor_name_suffixes[func]);

        sysfs_attr_init(&data->sensors[sensor].attr[func].dev_attr.attr);
        data->sensors[sensor].attr[func].dev_attr.attr.name = n;
        data->sensors[sensor].attr[func].dev_attr.attr.mode = 0444;
        data->sensors[sensor].attr[func].dev_attr.show = ibmpex_show_sensor;
        data->sensors[sensor].attr[func].index = sensor;
        data->sensors[sensor].attr[func].nr = func;

        err = device_create_file(data->bmc_device,
                                 &data->sensors[sensor].attr[func].dev_attr);
        if (err) {
                data->sensors[sensor].attr[func].dev_attr.attr.name = NULL;
                kfree(n);
                return err;
        }

        return 0;
}

static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
{
        int i, j, err;
        int sensor_type;
        int sensor_counter;
        int num_power = 0;
        int num_temp = 0;

        err = ibmpex_query_sensor_count(data);
        if (err <= 0)
                return -ENOENT;
        data->num_sensors = err;

        data->sensors = kzalloc_objs(*data->sensors, data->num_sensors);
        if (!data->sensors)
                return -ENOMEM;

        for (i = 0; i < data->num_sensors; i++) {
                err = ibmpex_query_sensor_name(data, i);
                if (err)
                        continue;

                if (is_power_sensor(data->rx_msg_data, data->rx_msg_len)) {
                        sensor_type = POWER_SENSOR;
                        num_power++;
                        sensor_counter = num_power;
                        data->sensors[i].multiplier =
                                power_sensor_multiplier(data,
                                                        data->rx_msg_data,
                                                        data->rx_msg_len);
                } else if (is_temp_sensor(data->rx_msg_data,
                                          data->rx_msg_len)) {
                        sensor_type = TEMP_SENSOR;
                        num_temp++;
                        sensor_counter = num_temp;
                        data->sensors[i].multiplier = 1000;
                } else
                        continue;

                data->sensors[i].in_use = 1;

                /* Create attributes */
                for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
                        err = create_sensor(data, sensor_type, sensor_counter,
                                            i, j);
                        if (err)
                                goto exit_remove;
                }
        }

        err = device_create_file(data->bmc_device,
                        &sensor_dev_attr_reset_high_low.dev_attr);
        if (err)
                goto exit_remove;

        err = device_create_file(data->bmc_device, &dev_attr_name.attr);
        if (err)
                goto exit_remove;

        return 0;

exit_remove:
        device_remove_file(data->bmc_device,
                           &sensor_dev_attr_reset_high_low.dev_attr);
        device_remove_file(data->bmc_device, &dev_attr_name.attr);
        for (i = 0; i < data->num_sensors; i++)
                for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
                        if (!data->sensors[i].attr[j].dev_attr.attr.name)
                                continue;
                        device_remove_file(data->bmc_device,
                                &data->sensors[i].attr[j].dev_attr);
                        kfree(data->sensors[i].attr[j].dev_attr.attr.name);
                }

        kfree(data->sensors);
        return err;
}

static void ibmpex_register_bmc(int iface, struct device *dev)
{
        struct ibmpex_bmc_data *data;
        int err;

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

        data->address.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
        data->address.channel = IPMI_BMC_CHANNEL;
        data->address.data[0] = 0;
        data->interface = iface;
        data->bmc_device = dev;

        /* Create IPMI messaging interface user */
        err = ipmi_create_user(data->interface, &driver_data.ipmi_hndlrs,
                               data, &data->user);
        if (err < 0) {
                dev_err(dev,
                        "Unable to register user with IPMI interface %d\n",
                        data->interface);
                goto out;
        }

        mutex_init(&data->lock);

        /* Initialize message */
        data->tx_msgid = 0;
        init_completion(&data->read_complete);
        data->tx_message.netfn = PEX_NET_FUNCTION;
        data->tx_message.cmd = PEX_COMMAND;
        data->tx_message.data = data->tx_msg_data;

        /* Does this BMC support PowerExecutive? */
        err = ibmpex_ver_check(data);
        if (err)
                goto out_user;

        /* Register the BMC as a HWMON class device */
        data->hwmon_dev = hwmon_device_register(data->bmc_device);

        if (IS_ERR(data->hwmon_dev)) {
                dev_err(data->bmc_device,
                        "Unable to register hwmon device for IPMI interface %d\n",
                        data->interface);
                goto out_user;
        }

        /* finally add the new bmc data to the bmc data list */
        dev_set_drvdata(dev, data);
        list_add_tail(&data->list, &driver_data.bmc_data);

        /* Now go find all the sensors */
        err = ibmpex_find_sensors(data);
        if (err) {
                dev_err(data->bmc_device, "Error %d finding sensors\n", err);
                goto out_register;
        }

        return;

out_register:
        list_del(&data->list);
        hwmon_device_unregister(data->hwmon_dev);
out_user:
        ipmi_destroy_user(data->user);
out:
        kfree(data);
}

static void ibmpex_bmc_delete(struct ibmpex_bmc_data *data)
{
        int i, j;

        device_remove_file(data->bmc_device,
                           &sensor_dev_attr_reset_high_low.dev_attr);
        device_remove_file(data->bmc_device, &dev_attr_name.attr);
        for (i = 0; i < data->num_sensors; i++)
                for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
                        if (!data->sensors[i].attr[j].dev_attr.attr.name)
                                continue;
                        device_remove_file(data->bmc_device,
                                &data->sensors[i].attr[j].dev_attr);
                        kfree(data->sensors[i].attr[j].dev_attr.attr.name);
                }

        list_del(&data->list);
        dev_set_drvdata(data->bmc_device, NULL);
        hwmon_device_unregister(data->hwmon_dev);
        ipmi_destroy_user(data->user);
        kfree(data->sensors);
        kfree(data);
}

static void ibmpex_bmc_gone(int iface)
{
        struct ibmpex_bmc_data *data = get_bmc_data(iface);

        if (!data)
                return;

        ibmpex_bmc_delete(data);
}

static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
{
        struct ibmpex_bmc_data *data = user_msg_data;

        if (msg->msgid != data->tx_msgid) {
                dev_err(data->bmc_device,
                        "Mismatch between received msgid (%02x) and transmitted msgid (%02x)!\n",
                        (int)msg->msgid,
                        (int)data->tx_msgid);
                ipmi_free_recv_msg(msg);
                return;
        }

        data->rx_recv_type = msg->recv_type;
        if (msg->msg.data_len > 0)
                data->rx_result = msg->msg.data[0];
        else
                data->rx_result = IPMI_UNKNOWN_ERR_COMPLETION_CODE;

        if (msg->msg.data_len > 1) {
                data->rx_msg_len = msg->msg.data_len - 1;
                memcpy(data->rx_msg_data, msg->msg.data + 1, data->rx_msg_len);
        } else
                data->rx_msg_len = 0;

        ipmi_free_recv_msg(msg);
        complete(&data->read_complete);
}

static int __init ibmpex_init(void)
{
        return ipmi_smi_watcher_register(&driver_data.bmc_events);
}

static void __exit ibmpex_exit(void)
{
        struct ibmpex_bmc_data *p, *next;

        ipmi_smi_watcher_unregister(&driver_data.bmc_events);
        list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
                ibmpex_bmc_delete(p);
}

MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
MODULE_DESCRIPTION("IBM PowerExecutive power/temperature sensor driver");
MODULE_LICENSE("GPL");

module_init(ibmpex_init);
module_exit(ibmpex_exit);

MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3350-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3550-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3650-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3655-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3755-*");