// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control. SMU based controls
 *
 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *                    <benh@kernel.crashing.org>
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/completion.h>
#include <linux/of.h>

#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>
#include <asm/smu.h>

#include "windfarm.h"

#define VERSION "0.4"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif

static int smu_supports_new_fans_ops = 1;

/*
 * SMU fans control object
 */

static LIST_HEAD(smu_fans);

struct smu_fan_control {
        struct list_head        link;
        int                     fan_type;       /* 0 = rpm, 1 = pwm */
        u32                     reg;            /* index in SMU */
        s32                     value;          /* current value */
        s32                     min, max;       /* min/max values */
        struct wf_control       ctrl;
};
#define to_smu_fan(c) container_of(c, struct smu_fan_control, ctrl)

static int smu_set_fan(int pwm, u8 id, u16 value)
{
        struct smu_cmd cmd;
        u8 buffer[16];
        DECLARE_COMPLETION_ONSTACK(comp);
        int rc;

        /* Fill SMU command structure */
        cmd.cmd = SMU_CMD_FAN_COMMAND;

        /* The SMU has an "old" and a "new" way of setting the fan speed
         * Unfortunately, I found no reliable way to know which one works
         * on a given machine model. After some investigations it appears
         * that MacOS X just tries the new one, and if it fails fallbacks
         * to the old ones ... Ugh.
         */
 retry:
        if (smu_supports_new_fans_ops) {
                buffer[0] = 0x30;
                buffer[1] = id;
                *((u16 *)(&buffer[2])) = value;
                cmd.data_len = 4;
        } else {
                if (id > 7)
                        return -EINVAL;
                /* Fill argument buffer */
                memset(buffer, 0, 16);
                buffer[0] = pwm ? 0x10 : 0x00;
                buffer[1] = 0x01 << id;
                *((u16 *)&buffer[2 + id * 2]) = value;
                cmd.data_len = 14;
        }

        cmd.reply_len = 16;
        cmd.data_buf = cmd.reply_buf = buffer;
        cmd.status = 0;
        cmd.done = smu_done_complete;
        cmd.misc = &comp;

        rc = smu_queue_cmd(&cmd);
        if (rc)
                return rc;
        wait_for_completion(&comp);

        /* Handle fallback (see comment above) */
        if (cmd.status != 0 && smu_supports_new_fans_ops) {
                printk(KERN_WARNING "windfarm: SMU failed new fan command "
                       "falling back to old method\n");
                smu_supports_new_fans_ops = 0;
                goto retry;
        }

        return cmd.status;
}

static void smu_fan_release(struct wf_control *ct)
{
        struct smu_fan_control *fct = to_smu_fan(ct);

        kfree(fct);
}

static int smu_fan_set(struct wf_control *ct, s32 value)
{
        struct smu_fan_control *fct = to_smu_fan(ct);

        if (value < fct->min)
                value = fct->min;
        if (value > fct->max)
                value = fct->max;
        fct->value = value;

        return smu_set_fan(fct->fan_type, fct->reg, value);
}

static int smu_fan_get(struct wf_control *ct, s32 *value)
{
        struct smu_fan_control *fct = to_smu_fan(ct);
        *value = fct->value; /* todo: read from SMU */
        return 0;
}

static s32 smu_fan_min(struct wf_control *ct)
{
        struct smu_fan_control *fct = to_smu_fan(ct);
        return fct->min;
}

static s32 smu_fan_max(struct wf_control *ct)
{
        struct smu_fan_control *fct = to_smu_fan(ct);
        return fct->max;
}

static const struct wf_control_ops smu_fan_ops = {
        .set_value      = smu_fan_set,
        .get_value      = smu_fan_get,
        .get_min        = smu_fan_min,
        .get_max        = smu_fan_max,
        .release        = smu_fan_release,
        .owner          = THIS_MODULE,
};

static struct smu_fan_control *smu_fan_create(struct device_node *node,
                                              int pwm_fan)
{
        struct smu_fan_control *fct;
        const s32 *v;
        const u32 *reg;
        const char *l;

        fct = kmalloc_obj(struct smu_fan_control);
        if (fct == NULL)
                return NULL;
        fct->ctrl.ops = &smu_fan_ops;
        l = of_get_property(node, "location", NULL);
        if (l == NULL)
                goto fail;

        fct->fan_type = pwm_fan;
        fct->ctrl.type = pwm_fan ? WF_CONTROL_PWM_FAN : WF_CONTROL_RPM_FAN;

        /* We use the name & location here the same way we do for SMU sensors,
         * see the comment in windfarm_smu_sensors.c. The locations are a bit
         * less consistent here between the iMac and the desktop models, but
         * that is good enough for our needs for now at least.
         *
         * One problem though is that Apple seem to be inconsistent with case
         * and the kernel doesn't have strcasecmp =P
         */

        fct->ctrl.name = NULL;

        /* Names used on desktop models */
        if (!strcmp(l, "Rear Fan 0") || !strcmp(l, "Rear Fan") ||
            !strcmp(l, "Rear fan 0") || !strcmp(l, "Rear fan") ||
            !strcmp(l, "CPU A EXHAUST"))
                fct->ctrl.name = "cpu-rear-fan-0";
        else if (!strcmp(l, "Rear Fan 1") || !strcmp(l, "Rear fan 1") ||
                 !strcmp(l, "CPU B EXHAUST"))
                fct->ctrl.name = "cpu-rear-fan-1";
        else if (!strcmp(l, "Front Fan 0") || !strcmp(l, "Front Fan") ||
                 !strcmp(l, "Front fan 0") || !strcmp(l, "Front fan") ||
                 !strcmp(l, "CPU A INTAKE"))
                fct->ctrl.name = "cpu-front-fan-0";
        else if (!strcmp(l, "Front Fan 1") || !strcmp(l, "Front fan 1") ||
                 !strcmp(l, "CPU B INTAKE"))
                fct->ctrl.name = "cpu-front-fan-1";
        else if (!strcmp(l, "CPU A PUMP"))
                fct->ctrl.name = "cpu-pump-0";
        else if (!strcmp(l, "CPU B PUMP"))
                fct->ctrl.name = "cpu-pump-1";
        else if (!strcmp(l, "Slots Fan") || !strcmp(l, "Slots fan") ||
                 !strcmp(l, "EXPANSION SLOTS INTAKE"))
                fct->ctrl.name = "slots-fan";
        else if (!strcmp(l, "Drive Bay") || !strcmp(l, "Drive bay") ||
                 !strcmp(l, "DRIVE BAY A INTAKE"))
                fct->ctrl.name = "drive-bay-fan";
        else if (!strcmp(l, "BACKSIDE"))
                fct->ctrl.name = "backside-fan";

        /* Names used on iMac models */
        if (!strcmp(l, "System Fan") || !strcmp(l, "System fan"))
                fct->ctrl.name = "system-fan";
        else if (!strcmp(l, "CPU Fan") || !strcmp(l, "CPU fan"))
                fct->ctrl.name = "cpu-fan";
        else if (!strcmp(l, "Hard Drive") || !strcmp(l, "Hard drive"))
                fct->ctrl.name = "drive-bay-fan";
        else if (!strcmp(l, "HDD Fan")) /* seen on iMac G5 iSight */
                fct->ctrl.name = "hard-drive-fan";
        else if (!strcmp(l, "ODD Fan")) /* same */
                fct->ctrl.name = "optical-drive-fan";

        /* Unrecognized fan, bail out */
        if (fct->ctrl.name == NULL)
                goto fail;

        /* Get min & max values*/
        v = of_get_property(node, "min-value", NULL);
        if (v == NULL)
                goto fail;
        fct->min = *v;
        v = of_get_property(node, "max-value", NULL);
        if (v == NULL)
                goto fail;
        fct->max = *v;

        /* Get "reg" value */
        reg = of_get_property(node, "reg", NULL);
        if (reg == NULL)
                goto fail;
        fct->reg = *reg;

        if (wf_register_control(&fct->ctrl))
                goto fail;

        return fct;
 fail:
        kfree(fct);
        return NULL;
}


static int __init smu_controls_init(void)
{
        struct device_node *smu, *fans, *fan;

        if (!smu_present())
                return -ENODEV;

        smu = of_find_node_by_type(NULL, "smu");
        if (smu == NULL)
                return -ENODEV;

        /* Look for RPM fans */
        for_each_child_of_node(smu, fans)
                if (of_node_name_eq(fans, "rpm-fans") ||
                    of_device_is_compatible(fans, "smu-rpm-fans"))
                        break;
        for_each_child_of_node(fans, fan) {
                struct smu_fan_control *fct;

                fct = smu_fan_create(fan, 0);
                if (fct == NULL) {
                        printk(KERN_WARNING "windfarm: Failed to create SMU "
                               "RPM fan %pOFn\n", fan);
                        continue;
                }
                list_add(&fct->link, &smu_fans);
        }
        of_node_put(fans);


        /* Look for PWM fans */
        for_each_child_of_node(smu, fans)
                if (of_node_name_eq(fans, "pwm-fans"))
                        break;
        for_each_child_of_node(fans, fan) {
                struct smu_fan_control *fct;

                fct = smu_fan_create(fan, 1);
                if (fct == NULL) {
                        printk(KERN_WARNING "windfarm: Failed to create SMU "
                               "PWM fan %pOFn\n", fan);
                        continue;
                }
                list_add(&fct->link, &smu_fans);
        }
        of_node_put(fans);
        of_node_put(smu);

        return 0;
}

static void __exit smu_controls_exit(void)
{
        struct smu_fan_control *fct;

        while (!list_empty(&smu_fans)) {
                fct = list_entry(smu_fans.next, struct smu_fan_control, link);
                list_del(&fct->link);
                wf_unregister_control(&fct->ctrl);
        }
}


module_init(smu_controls_init);
module_exit(smu_controls_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("SMU control objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");