// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control.  SMU "satellite" controller sensors.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

#include <asm/smu.h>
#include <asm/pmac_low_i2c.h>

#include "windfarm.h"

#define VERSION "1.0"

/* If the cache is older than 800ms we'll refetch it */
#define MAX_AGE         msecs_to_jiffies(800)

struct wf_sat {
        struct kref             ref;
        int                     nr;
        struct mutex            mutex;
        unsigned long           last_read; /* jiffies when cache last updated */
        u8                      cache[16];
        struct list_head        sensors;
        struct i2c_client       *i2c;
        struct device_node      *node;
};

static struct wf_sat *sats[2];

struct wf_sat_sensor {
        struct list_head        link;
        int                     index;
        int                     index2;         /* used for power sensors */
        int                     shift;
        struct wf_sat           *sat;
        struct wf_sensor        sens;
};

#define wf_to_sat(c)    container_of(c, struct wf_sat_sensor, sens)

struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
                                                  unsigned int *size)
{
        struct wf_sat *sat;
        int err;
        unsigned int i, len;
        u8 *buf;
        u8 data[4];

        /* TODO: Add the resulting partition to the device-tree */

        if (sat_id > 1 || (sat = sats[sat_id]) == NULL)
                return NULL;

        err = i2c_smbus_write_word_data(sat->i2c, 8, id << 8);
        if (err) {
                printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
                return NULL;
        }

        err = i2c_smbus_read_word_data(sat->i2c, 9);
        if (err < 0) {
                printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
                return NULL;
        }
        len = err;
        if (len == 0) {
                printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
                return NULL;
        }

        len = le16_to_cpu(len);
        len = (len + 3) & ~3;
        buf = kmalloc(len, GFP_KERNEL);
        if (buf == NULL)
                return NULL;

        for (i = 0; i < len; i += 4) {
                err = i2c_smbus_read_i2c_block_data(sat->i2c, 0xa, 4, data);
                if (err < 0) {
                        printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
                               err);
                        goto fail;
                }
                buf[i] = data[1];
                buf[i+1] = data[0];
                buf[i+2] = data[3];
                buf[i+3] = data[2];
        }

        printk(KERN_DEBUG "sat %d partition %x:", sat_id, id);
        print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
                       16, 1, buf, len, false);
        if (size)
                *size = len;
        return (struct smu_sdbp_header *) buf;

 fail:
        kfree(buf);
        return NULL;
}
EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);

/* refresh the cache */
static int wf_sat_read_cache(struct wf_sat *sat)
{
        int err;

        err = i2c_smbus_read_i2c_block_data(sat->i2c, 0x3f, 16, sat->cache);
        if (err < 0)
                return err;
        sat->last_read = jiffies;

#ifdef LOTSA_DEBUG
        {
                int i;
                printk(KERN_DEBUG "wf_sat_get: data is");
                print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
                               16, 1, sat->cache, 16, false);
        }
#endif
        return 0;
}

static int wf_sat_sensor_get(struct wf_sensor *sr, s32 *value)
{
        struct wf_sat_sensor *sens = wf_to_sat(sr);
        struct wf_sat *sat = sens->sat;
        int i, err;
        s32 val;

        if (sat->i2c == NULL)
                return -ENODEV;

        mutex_lock(&sat->mutex);
        if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
                err = wf_sat_read_cache(sat);
                if (err)
                        goto fail;
        }

        i = sens->index * 2;
        val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
        if (sens->index2 >= 0) {
                i = sens->index2 * 2;
                /* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
                val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
        }

        *value = val;
        err = 0;

 fail:
        mutex_unlock(&sat->mutex);
        return err;
}

static void wf_sat_release(struct kref *ref)
{
        struct wf_sat *sat = container_of(ref, struct wf_sat, ref);

        if (sat->nr >= 0)
                sats[sat->nr] = NULL;
        of_node_put(sat->node);
        kfree(sat);
}

static void wf_sat_sensor_release(struct wf_sensor *sr)
{
        struct wf_sat_sensor *sens = wf_to_sat(sr);
        struct wf_sat *sat = sens->sat;

        kfree(sens);
        kref_put(&sat->ref, wf_sat_release);
}

static const struct wf_sensor_ops wf_sat_ops = {
        .get_value      = wf_sat_sensor_get,
        .release        = wf_sat_sensor_release,
        .owner          = THIS_MODULE,
};

static int wf_sat_probe(struct i2c_client *client)
{
        struct device_node *dev = client->dev.of_node;
        struct wf_sat *sat;
        struct wf_sat_sensor *sens;
        const u32 *reg;
        const char *loc;
        u8 chip, core;
        struct device_node *child;
        int shift, cpu, index;
        char *name;
        int vsens[2], isens[2];

        sat = kzalloc_obj(struct wf_sat);
        if (sat == NULL)
                return -ENOMEM;
        sat->nr = -1;
        sat->node = of_node_get(dev);
        kref_init(&sat->ref);
        mutex_init(&sat->mutex);
        sat->i2c = client;
        INIT_LIST_HEAD(&sat->sensors);
        i2c_set_clientdata(client, sat);

        vsens[0] = vsens[1] = -1;
        isens[0] = isens[1] = -1;
        for_each_child_of_node(dev, child) {
                reg = of_get_property(child, "reg", NULL);
                loc = of_get_property(child, "location", NULL);
                if (reg == NULL || loc == NULL)
                        continue;

                /* the cooked sensors are between 0x30 and 0x37 */
                if (*reg < 0x30 || *reg > 0x37)
                        continue;
                index = *reg - 0x30;

                /* expect location to be CPU [AB][01] ... */
                if (strncmp(loc, "CPU ", 4) != 0)
                        continue;
                chip = loc[4] - 'A';
                core = loc[5] - '0';
                if (chip > 1 || core > 1) {
                        printk(KERN_ERR "wf_sat_create: don't understand "
                               "location %s for %pOF\n", loc, child);
                        continue;
                }
                cpu = 2 * chip + core;
                if (sat->nr < 0)
                        sat->nr = chip;
                else if (sat->nr != chip) {
                        printk(KERN_ERR "wf_sat_create: can't cope with "
                               "multiple CPU chips on one SAT (%s)\n", loc);
                        continue;
                }

                if (of_node_is_type(child, "voltage-sensor")) {
                        name = "cpu-voltage";
                        shift = 4;
                        vsens[core] = index;
                } else if (of_node_is_type(child, "current-sensor")) {
                        name = "cpu-current";
                        shift = 8;
                        isens[core] = index;
                } else if (of_node_is_type(child, "temp-sensor")) {
                        name = "cpu-temp";
                        shift = 10;
                } else
                        continue;       /* hmmm shouldn't happen */

                /* the +16 is enough for "cpu-voltage-n" */
                sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
                if (sens == NULL) {
                        printk(KERN_ERR "wf_sat_create: couldn't create "
                               "%s sensor %d (no memory)\n", name, cpu);
                        continue;
                }
                sens->index = index;
                sens->index2 = -1;
                sens->shift = shift;
                sens->sat = sat;
                sens->sens.ops = &wf_sat_ops;
                sens->sens.name = (char *) (sens + 1);
                snprintf((char *)sens->sens.name, 16, "%s-%d", name, cpu);

                if (wf_register_sensor(&sens->sens))
                        kfree(sens);
                else {
                        list_add(&sens->link, &sat->sensors);
                        kref_get(&sat->ref);
                }
        }

        /* make the power sensors */
        for (core = 0; core < 2; ++core) {
                if (vsens[core] < 0 || isens[core] < 0)
                        continue;
                cpu = 2 * sat->nr + core;
                sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
                if (sens == NULL) {
                        printk(KERN_ERR "wf_sat_create: couldn't create power "
                               "sensor %d (no memory)\n", cpu);
                        continue;
                }
                sens->index = vsens[core];
                sens->index2 = isens[core];
                sens->shift = 0;
                sens->sat = sat;
                sens->sens.ops = &wf_sat_ops;
                sens->sens.name = (char *) (sens + 1);
                snprintf((char *)sens->sens.name, 16, "cpu-power-%d", cpu);

                if (wf_register_sensor(&sens->sens))
                        kfree(sens);
                else {
                        list_add(&sens->link, &sat->sensors);
                        kref_get(&sat->ref);
                }
        }

        if (sat->nr >= 0)
                sats[sat->nr] = sat;

        return 0;
}

static void wf_sat_remove(struct i2c_client *client)
{
        struct wf_sat *sat = i2c_get_clientdata(client);
        struct wf_sat_sensor *sens;

        /* release sensors */
        while(!list_empty(&sat->sensors)) {
                sens = list_first_entry(&sat->sensors,
                                        struct wf_sat_sensor, link);
                list_del(&sens->link);
                wf_unregister_sensor(&sens->sens);
        }
        sat->i2c = NULL;
        kref_put(&sat->ref, wf_sat_release);
}

static const struct i2c_device_id wf_sat_id[] = {
        { "MAC,smu-sat" },
        { }
};
MODULE_DEVICE_TABLE(i2c, wf_sat_id);

static const struct of_device_id wf_sat_of_id[] = {
        { .compatible = "smu-sat", },
        { }
};
MODULE_DEVICE_TABLE(of, wf_sat_of_id);

static struct i2c_driver wf_sat_driver = {
        .driver = {
                .name           = "wf_smu_sat",
                .of_match_table = wf_sat_of_id,
        },
        .probe          = wf_sat_probe,
        .remove         = wf_sat_remove,
        .id_table       = wf_sat_id,
};

module_i2c_driver(wf_sat_driver);

MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
MODULE_LICENSE("GPL");