/*
 * Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/idr.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <sound/ac97/codec.h>
#include <sound/ac97/controller.h>
#include <sound/ac97/regs.h>

#include "ac97_core.h"

/*
 * Protects ac97_controllers and each ac97_controller structure.
 */
static DEFINE_MUTEX(ac97_controllers_mutex);
static DEFINE_IDR(ac97_adapter_idr);
static LIST_HEAD(ac97_controllers);

static struct bus_type ac97_bus_type;

static inline struct ac97_controller*
to_ac97_controller(struct device *ac97_adapter)
{
        return container_of(ac97_adapter, struct ac97_controller, adap);
}

static int ac97_unbound_ctrl_write(struct ac97_controller *adrv, int slot,
                     unsigned short reg, unsigned short val)
{
        return -ENODEV;
}

static int ac97_unbound_ctrl_read(struct ac97_controller *adrv, int slot,
                                  unsigned short reg)
{
        return -ENODEV;
}

static const struct ac97_controller_ops ac97_unbound_ctrl_ops = {
        .write = ac97_unbound_ctrl_write,
        .read = ac97_unbound_ctrl_read,
};

static struct ac97_controller ac97_unbound_ctrl = {
        .ops = &ac97_unbound_ctrl_ops,
};

static struct ac97_codec_device *
ac97_codec_find(struct ac97_controller *ac97_ctrl, unsigned int codec_num)
{
        if (codec_num >= AC97_BUS_MAX_CODECS)
                return ERR_PTR(-EINVAL);

        return ac97_ctrl->codecs[codec_num];
}

static struct device_node *
ac97_of_get_child_device(struct ac97_controller *ac97_ctrl, int idx,
                         unsigned int vendor_id)
{
        struct device_node *node;
        u32 reg;
        char compat[] = "ac97,0000,0000";

        snprintf(compat, sizeof(compat), "ac97,%04x,%04x",
                 vendor_id >> 16, vendor_id & 0xffff);

        for_each_child_of_node(ac97_ctrl->parent->of_node, node) {
                if ((idx != of_property_read_u32(node, "reg", &reg)) ||
                    !of_device_is_compatible(node, compat))
                        continue;
                return node;
        }

        return NULL;
}

static void ac97_codec_release(struct device *dev)
{
        struct ac97_codec_device *adev;
        struct ac97_controller *ac97_ctrl;

        adev = to_ac97_device(dev);
        ac97_ctrl = adev->ac97_ctrl;
        ac97_ctrl->codecs[adev->num] = NULL;
        of_node_put(dev->of_node);
        kfree(adev);
}

static int ac97_codec_add(struct ac97_controller *ac97_ctrl, int idx,
                   unsigned int vendor_id)
{
        struct ac97_codec_device *codec;
        int ret;

        codec = kzalloc(sizeof(*codec), GFP_KERNEL);
        if (!codec)
                return -ENOMEM;
        ac97_ctrl->codecs[idx] = codec;
        codec->vendor_id = vendor_id;
        codec->dev.release = ac97_codec_release;
        codec->dev.bus = &ac97_bus_type;
        codec->dev.parent = &ac97_ctrl->adap;
        codec->num = idx;
        codec->ac97_ctrl = ac97_ctrl;

        device_initialize(&codec->dev);
        dev_set_name(&codec->dev, "%s:%u", dev_name(ac97_ctrl->parent), idx);
        codec->dev.of_node = ac97_of_get_child_device(ac97_ctrl, idx,
                                                      vendor_id);

        ret = device_add(&codec->dev);
        if (ret)
                goto err_free_codec;

        return 0;
err_free_codec:
        of_node_put(codec->dev.of_node);
        put_device(&codec->dev);
        kfree(codec);
        ac97_ctrl->codecs[idx] = NULL;

        return ret;
}

unsigned int snd_ac97_bus_scan_one(struct ac97_controller *adrv,
                                   unsigned int codec_num)
{
        unsigned short vid1, vid2;
        int ret;

        ret = adrv->ops->read(adrv, codec_num, AC97_VENDOR_ID1);
        vid1 = (ret & 0xffff);
        if (ret < 0)
                return 0;

        ret = adrv->ops->read(adrv, codec_num, AC97_VENDOR_ID2);
        vid2 = (ret & 0xffff);
        if (ret < 0)
                return 0;

        dev_dbg(&adrv->adap, "%s(codec_num=%u): vendor_id=0x%08x\n",
                __func__, codec_num, AC97_ID(vid1, vid2));
        return AC97_ID(vid1, vid2);
}

static int ac97_bus_scan(struct ac97_controller *ac97_ctrl)
{
        int ret, i;
        unsigned int vendor_id;

        for (i = 0; i < AC97_BUS_MAX_CODECS; i++) {
                if (ac97_codec_find(ac97_ctrl, i))
                        continue;
                if (!(ac97_ctrl->slots_available & BIT(i)))
                        continue;
                vendor_id = snd_ac97_bus_scan_one(ac97_ctrl, i);
                if (!vendor_id)
                        continue;

                ret = ac97_codec_add(ac97_ctrl, i, vendor_id);
                if (ret < 0)
                        return ret;
        }
        return 0;
}

static int ac97_bus_reset(struct ac97_controller *ac97_ctrl)
{
        ac97_ctrl->ops->reset(ac97_ctrl);

        return 0;
}

/**
 * snd_ac97_codec_driver_register - register an AC97 codec driver
 * @dev: AC97 driver codec to register
 *
 * Register an AC97 codec driver to the ac97 bus driver, aka. the AC97 digital
 * controller.
 *
 * Returns 0 on success or error code
 */
int snd_ac97_codec_driver_register(struct ac97_codec_driver *drv)
{
        drv->driver.bus = &ac97_bus_type;
        return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(snd_ac97_codec_driver_register);

/**
 * snd_ac97_codec_driver_unregister - unregister an AC97 codec driver
 * @dev: AC97 codec driver to unregister
 *
 * Unregister a previously registered ac97 codec driver.
 */
void snd_ac97_codec_driver_unregister(struct ac97_codec_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(snd_ac97_codec_driver_unregister);

/**
 * snd_ac97_codec_get_platdata - get platform_data
 * @adev: the ac97 codec device
 *
 * For legacy platforms, in order to have platform_data in codec drivers
 * available, while ac97 device are auto-created upon probe, this retrieves the
 * platdata which was setup on ac97 controller registration.
 *
 * Returns the platform data pointer
 */
void *snd_ac97_codec_get_platdata(const struct ac97_codec_device *adev)
{
        struct ac97_controller *ac97_ctrl = adev->ac97_ctrl;

        return ac97_ctrl->codecs_pdata[adev->num];
}
EXPORT_SYMBOL_GPL(snd_ac97_codec_get_platdata);

static void ac97_ctrl_codecs_unregister(struct ac97_controller *ac97_ctrl)
{
        int i;

        for (i = 0; i < AC97_BUS_MAX_CODECS; i++)
                if (ac97_ctrl->codecs[i]) {
                        ac97_ctrl->codecs[i]->ac97_ctrl = &ac97_unbound_ctrl;
                        device_unregister(&ac97_ctrl->codecs[i]->dev);
                }
}

static ssize_t cold_reset_store(struct device *dev,
                                struct device_attribute *attr, const char *buf,
                                size_t len)
{
        struct ac97_controller *ac97_ctrl;

        mutex_lock(&ac97_controllers_mutex);
        ac97_ctrl = to_ac97_controller(dev);
        ac97_ctrl->ops->reset(ac97_ctrl);
        mutex_unlock(&ac97_controllers_mutex);
        return len;
}
static DEVICE_ATTR_WO(cold_reset);

static ssize_t warm_reset_store(struct device *dev,
                                struct device_attribute *attr, const char *buf,
                                size_t len)
{
        struct ac97_controller *ac97_ctrl;

        if (!dev)
                return -ENODEV;

        mutex_lock(&ac97_controllers_mutex);
        ac97_ctrl = to_ac97_controller(dev);
        ac97_ctrl->ops->warm_reset(ac97_ctrl);
        mutex_unlock(&ac97_controllers_mutex);
        return len;
}
static DEVICE_ATTR_WO(warm_reset);

static struct attribute *ac97_controller_device_attrs[] = {
        &dev_attr_cold_reset.attr,
        &dev_attr_warm_reset.attr,
        NULL
};

static struct attribute_group ac97_adapter_attr_group = {
        .name   = "ac97_operations",
        .attrs  = ac97_controller_device_attrs,
};

static const struct attribute_group *ac97_adapter_groups[] = {
        &ac97_adapter_attr_group,
        NULL,
};

static void ac97_del_adapter(struct ac97_controller *ac97_ctrl)
{
        mutex_lock(&ac97_controllers_mutex);
        ac97_ctrl_codecs_unregister(ac97_ctrl);
        list_del(&ac97_ctrl->controllers);
        mutex_unlock(&ac97_controllers_mutex);

        device_unregister(&ac97_ctrl->adap);
}

static void ac97_adapter_release(struct device *dev)
{
        struct ac97_controller *ac97_ctrl;

        ac97_ctrl = to_ac97_controller(dev);
        idr_remove(&ac97_adapter_idr, ac97_ctrl->nr);
        dev_dbg(&ac97_ctrl->adap, "adapter unregistered by %s\n",
                dev_name(ac97_ctrl->parent));
}

static const struct device_type ac97_adapter_type = {
        .groups         = ac97_adapter_groups,
        .release        = ac97_adapter_release,
};

static int ac97_add_adapter(struct ac97_controller *ac97_ctrl)
{
        int ret;

        mutex_lock(&ac97_controllers_mutex);
        ret = idr_alloc(&ac97_adapter_idr, ac97_ctrl, 0, 0, GFP_KERNEL);
        ac97_ctrl->nr = ret;
        if (ret >= 0) {
                dev_set_name(&ac97_ctrl->adap, "ac97-%d", ret);
                ac97_ctrl->adap.type = &ac97_adapter_type;
                ac97_ctrl->adap.parent = ac97_ctrl->parent;
                ret = device_register(&ac97_ctrl->adap);
                if (ret)
                        put_device(&ac97_ctrl->adap);
        }
        if (!ret)
                list_add(&ac97_ctrl->controllers, &ac97_controllers);
        mutex_unlock(&ac97_controllers_mutex);

        if (!ret)
                dev_dbg(&ac97_ctrl->adap, "adapter registered by %s\n",
                        dev_name(ac97_ctrl->parent));
        return ret;
}

/**
 * snd_ac97_controller_register - register an ac97 controller
 * @ops: the ac97 bus operations
 * @dev: the device providing the ac97 DC function
 * @slots_available: mask of the ac97 codecs that can be scanned and probed
 *                   bit0 => codec 0, bit1 => codec 1 ... bit 3 => codec 3
 *
 * Register a digital controller which can control up to 4 ac97 codecs. This is
 * the controller side of the AC97 AC-link, while the slave side are the codecs.
 *
 * Returns a valid controller upon success, negative pointer value upon error
 */
struct ac97_controller *snd_ac97_controller_register(
        const struct ac97_controller_ops *ops, struct device *dev,
        unsigned short slots_available, void **codecs_pdata)
{
        struct ac97_controller *ac97_ctrl;
        int ret, i;

        ac97_ctrl = kzalloc(sizeof(*ac97_ctrl), GFP_KERNEL);
        if (!ac97_ctrl)
                return ERR_PTR(-ENOMEM);

        for (i = 0; i < AC97_BUS_MAX_CODECS && codecs_pdata; i++)
                ac97_ctrl->codecs_pdata[i] = codecs_pdata[i];

        ac97_ctrl->ops = ops;
        ac97_ctrl->slots_available = slots_available;
        ac97_ctrl->parent = dev;
        ret = ac97_add_adapter(ac97_ctrl);

        if (ret)
                goto err;
        ac97_bus_reset(ac97_ctrl);
        ac97_bus_scan(ac97_ctrl);

        return ac97_ctrl;
err:
        kfree(ac97_ctrl);
        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(snd_ac97_controller_register);

/**
 * snd_ac97_controller_unregister - unregister an ac97 controller
 * @ac97_ctrl: the device previously provided to ac97_controller_register()
 *
 */
void snd_ac97_controller_unregister(struct ac97_controller *ac97_ctrl)
{
        ac97_del_adapter(ac97_ctrl);
}
EXPORT_SYMBOL_GPL(snd_ac97_controller_unregister);

#ifdef CONFIG_PM
static int ac97_pm_runtime_suspend(struct device *dev)
{
        struct ac97_codec_device *codec = to_ac97_device(dev);
        int ret = pm_generic_runtime_suspend(dev);

        if (ret == 0 && dev->driver) {
                if (pm_runtime_is_irq_safe(dev))
                        clk_disable(codec->clk);
                else
                        clk_disable_unprepare(codec->clk);
        }

        return ret;
}

static int ac97_pm_runtime_resume(struct device *dev)
{
        struct ac97_codec_device *codec = to_ac97_device(dev);
        int ret;

        if (dev->driver) {
                if (pm_runtime_is_irq_safe(dev))
                        ret = clk_enable(codec->clk);
                else
                        ret = clk_prepare_enable(codec->clk);
                if (ret)
                        return ret;
        }

        return pm_generic_runtime_resume(dev);
}
#endif /* CONFIG_PM */

static const struct dev_pm_ops ac97_pm = {
        .suspend        = pm_generic_suspend,
        .resume         = pm_generic_resume,
        .freeze         = pm_generic_freeze,
        .thaw           = pm_generic_thaw,
        .poweroff       = pm_generic_poweroff,
        .restore        = pm_generic_restore,
        SET_RUNTIME_PM_OPS(
                ac97_pm_runtime_suspend,
                ac97_pm_runtime_resume,
                NULL)
};

static int ac97_get_enable_clk(struct ac97_codec_device *adev)
{
        int ret;

        adev->clk = clk_get(&adev->dev, "ac97_clk");
        if (IS_ERR(adev->clk))
                return PTR_ERR(adev->clk);

        ret = clk_prepare_enable(adev->clk);
        if (ret)
                clk_put(adev->clk);

        return ret;
}

static void ac97_put_disable_clk(struct ac97_codec_device *adev)
{
        clk_disable_unprepare(adev->clk);
        clk_put(adev->clk);
}

static ssize_t vendor_id_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct ac97_codec_device *codec = to_ac97_device(dev);

        return sprintf(buf, "%08x", codec->vendor_id);
}
DEVICE_ATTR_RO(vendor_id);

static struct attribute *ac97_dev_attrs[] = {
        &dev_attr_vendor_id.attr,
        NULL,
};
ATTRIBUTE_GROUPS(ac97_dev);

static int ac97_bus_match(struct device *dev, struct device_driver *drv)
{
        struct ac97_codec_device *adev = to_ac97_device(dev);
        struct ac97_codec_driver *adrv = to_ac97_driver(drv);
        const struct ac97_id *id = adrv->id_table;
        int i = 0;

        if (adev->vendor_id == 0x0 || adev->vendor_id == 0xffffffff)
                return false;

        do {
                if (ac97_ids_match(id[i].id, adev->vendor_id, id[i].mask))
                        return true;
        } while (id[i++].id);

        return false;
}

static int ac97_bus_probe(struct device *dev)
{
        struct ac97_codec_device *adev = to_ac97_device(dev);
        struct ac97_codec_driver *adrv = to_ac97_driver(dev->driver);
        int ret;

        ret = ac97_get_enable_clk(adev);
        if (ret)
                return ret;

        pm_runtime_get_noresume(dev);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);

        ret = adrv->probe(adev);
        if (ret == 0)
                return 0;

        pm_runtime_disable(dev);
        pm_runtime_set_suspended(dev);
        pm_runtime_put_noidle(dev);
        ac97_put_disable_clk(adev);

        return ret;
}

static int ac97_bus_remove(struct device *dev)
{
        struct ac97_codec_device *adev = to_ac97_device(dev);
        struct ac97_codec_driver *adrv = to_ac97_driver(dev->driver);
        int ret;

        ret = pm_runtime_get_sync(dev);
        if (ret < 0)
                return ret;

        ret = adrv->remove(adev);
        pm_runtime_put_noidle(dev);
        if (ret == 0)
                ac97_put_disable_clk(adev);

        pm_runtime_disable(dev);

        return ret;
}

static struct bus_type ac97_bus_type = {
        .name           = "ac97bus",
        .dev_groups     = ac97_dev_groups,
        .match          = ac97_bus_match,
        .pm             = &ac97_pm,
        .probe          = ac97_bus_probe,
        .remove         = ac97_bus_remove,
};

static int __init ac97_bus_init(void)
{
        return bus_register(&ac97_bus_type);
}
subsys_initcall(ac97_bus_init);

static void __exit ac97_bus_exit(void)
{
        bus_unregister(&ac97_bus_type);
}
module_exit(ac97_bus_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");